security/selinux/ss/services.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Implementation of the security services.
   4  *
   5  * Authors : Stephen Smalley, <stephen.smalley.work@gmail.com>
   6  *           James Morris <jmorris@redhat.com>
   7  *
   8  * Updated: Trusted Computer Solutions, Inc. <dgoeddel@trustedcs.com>
   9  *
  10  *      Support for enhanced MLS infrastructure.
  11  *      Support for context based audit filters.
  12  *
  13  * Updated: Frank Mayer <mayerf@tresys.com> and Karl MacMillan <kmacmillan@tresys.com>
  14  *
  15  *      Added conditional policy language extensions
  16  *
  17  * Updated: Hewlett-Packard <paul@paul-moore.com>
  18  *
  19  *      Added support for NetLabel
  20  *      Added support for the policy capability bitmap
  21  *
  22  * Updated: Chad Sellers <csellers@tresys.com>
  23  *
  24  *  Added validation of kernel classes and permissions
  25  *
  26  * Updated: KaiGai Kohei <kaigai@ak.jp.nec.com>
  27  *
  28  *  Added support for bounds domain and audit messaged on masked permissions
  29  *
  30  * Updated: Guido Trentalancia <guido@trentalancia.com>
  31  *
  32  *  Added support for runtime switching of the policy type
  33  *
  34  * Copyright (C) 2008, 2009 NEC Corporation
  35  * Copyright (C) 2006, 2007 Hewlett-Packard Development Company, L.P.
  36  * Copyright (C) 2004-2006 Trusted Computer Solutions, Inc.
  37  * Copyright (C) 2003 - 2004, 2006 Tresys Technology, LLC
  38  * Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com>
  39  */
  40 #include <linux/kernel.h>
  41 #include <linux/slab.h>
  42 #include <linux/string.h>
  43 #include <linux/spinlock.h>
  44 #include <linux/rcupdate.h>
  45 #include <linux/errno.h>
  46 #include <linux/in.h>
  47 #include <linux/sched.h>
  48 #include <linux/audit.h>
  49 #include <linux/vmalloc.h>
  50 #include <linux/lsm_hooks.h>
  51 #include <net/netlabel.h>
  52
  53 #include "flask.h"
  54 #include "avc.h"
  55 #include "avc_ss.h"
  56 #include "security.h"
  57 #include "context.h"
  58 #include "policydb.h"
  59 #include "sidtab.h"
  60 #include "services.h"
  61 #include "conditional.h"
  62 #include "mls.h"
  63 #include "objsec.h"
  64 #include "netlabel.h"
  65 #include "xfrm.h"
  66 #include "ebitmap.h"
  67 #include "audit.h"
  68 #include "policycap_names.h"
  69 #include "ima.h"
  70
  71 struct selinux_policy_convert_data {
  72         struct convert_context_args args;
  73         struct sidtab_convert_params sidtab_params;
  74 };
  75
  76 /* Forward declaration. */
  77 static int context_struct_to_string(struct policydb *policydb,
  78                                     struct context *context,
  79                                     char **scontext,
  80                                     u32 *scontext_len);
  81
  82 static int sidtab_entry_to_string(struct policydb *policydb,
  83                                   struct sidtab *sidtab,
  84                                   struct sidtab_entry *entry,
  85                                   char **scontext,
  86                                   u32 *scontext_len);
  87
  88 static void context_struct_compute_av(struct policydb *policydb,
  89                                       struct context *scontext,
  90                                       struct context *tcontext,
  91                                       u16 tclass,
  92                                       struct av_decision *avd,
  93                                       struct extended_perms *xperms);
  94
  95 static int selinux_set_mapping(struct policydb *pol,
  96                                const struct security_class_mapping *map,
  97                                struct selinux_map *out_map)
  98 {
  99         u16 i, j;
 100         bool print_unknown_handle = false;
 101
 102         /* Find number of classes in the input mapping */
 103         if (!map)
 104                 return -EINVAL;
 105         i = 0;
 106         while (map[i].name)
 107                 i++;
 108
 109         /* Allocate space for the class records, plus one for class zero */
 110         out_map->mapping = kcalloc(++i, sizeof(*out_map->mapping), GFP_ATOMIC);
 111         if (!out_map->mapping)
 112                 return -ENOMEM;
 113
 114         /* Store the raw class and permission values */
 115         j = 0;
 116         while (map[j].name) {
 117                 const struct security_class_mapping *p_in = map + (j++);
 118                 struct selinux_mapping *p_out = out_map->mapping + j;
 119                 u16 k;
 120
 121                 /* An empty class string skips ahead */
 122                 if (!strcmp(p_in->name, "")) {
 123                         p_out->num_perms = 0;
 124                         continue;
 125                 }
 126
 127                 p_out->value = string_to_security_class(pol, p_in->name);
 128                 if (!p_out->value) {
 129                         pr_info("SELinux:  Class %s not defined in policy.\n",
 130                                p_in->name);
 131                         if (pol->reject_unknown)
 132                                 goto err;
 133                         p_out->num_perms = 0;
 134                         print_unknown_handle = true;
 135                         continue;
 136                 }
 137
 138                 k = 0;
 139                 while (p_in->perms[k]) {
 140                         /* An empty permission string skips ahead */
 141                         if (!*p_in->perms[k]) {
 142                                 k++;
 143                                 continue;
 144                         }
 145                         p_out->perms[k] = string_to_av_perm(pol, p_out->value,
 146                                                             p_in->perms[k]);
 147                         if (!p_out->perms[k]) {
 148                                 pr_info("SELinux:  Permission %s in class %s not defined in policy.\n",
 149                                        p_in->perms[k], p_in->name);
 150                                 if (pol->reject_unknown)
 151                                         goto err;
 152                                 print_unknown_handle = true;
 153                         }
 154
 155                         k++;
 156                 }
 157                 p_out->num_perms = k;
 158         }
 159
 160         if (print_unknown_handle)
 161                 pr_info("SELinux: the above unknown classes and permissions will be %s\n",
 162                        pol->allow_unknown ? "allowed" : "denied");
 163
 164         out_map->size = i;
 165         return 0;
 166 err:
 167         kfree(out_map->mapping);
 168         out_map->mapping = NULL;
 169         return -EINVAL;
 170 }
 171
 172 /*
 173  * Get real, policy values from mapped values
 174  */
 175
 176 static u16 unmap_class(struct selinux_map *map, u16 tclass)
 177 {
 178         if (tclass < map->size)
 179                 return map->mapping[tclass].value;
 180
 181         return tclass;
 182 }
 183
 184 /*
 185  * Get kernel value for class from its policy value
 186  */
 187 static u16 map_class(struct selinux_map *map, u16 pol_value)
 188 {
 189         u16 i;
 190
 191         for (i = 1; i < map->size; i++) {
 192                 if (map->mapping[i].value == pol_value)
 193                         return i;
 194         }
 195
 196         return SECCLASS_NULL;
 197 }
 198
 199 static void map_decision(struct selinux_map *map,
 200                          u16 tclass, struct av_decision *avd,
 201                          int allow_unknown)
 202 {
 203         if (tclass < map->size) {
 204                 struct selinux_mapping *mapping = &map->mapping[tclass];
 205                 unsigned int i, n = mapping->num_perms;
 206                 u32 result;
 207
 208                 for (i = 0, result = 0; i < n; i++) {
 209                         if (avd->allowed & mapping->perms[i])
 210                                 result |= (u32)1<<i;
 211                         if (allow_unknown && !mapping->perms[i])
 212                                 result |= (u32)1<<i;
 213                 }
 214                 avd->allowed = result;
 215
 216                 for (i = 0, result = 0; i < n; i++)
 217                         if (avd->auditallow & mapping->perms[i])
 218                                 result |= (u32)1<<i;
 219                 avd->auditallow = result;
 220
 221                 for (i = 0, result = 0; i < n; i++) {
 222                         if (avd->auditdeny & mapping->perms[i])
 223                                 result |= (u32)1<<i;
 224                         if (!allow_unknown && !mapping->perms[i])
 225                                 result |= (u32)1<<i;
 226                 }
 227                 /*
 228                  * In case the kernel has a bug and requests a permission
 229                  * between num_perms and the maximum permission number, we
 230                  * should audit that denial
 231                  */
 232                 for (; i < (sizeof(u32)*8); i++)
 233                         result |= (u32)1<<i;
 234                 avd->auditdeny = result;
 235         }
 236 }
 237
 238 int security_mls_enabled(void)
 239 {
 240         int mls_enabled;
 241         struct selinux_policy *policy;
 242
 243         if (!selinux_initialized())
 244                 return 0;
 245
 246         rcu_read_lock();
 247         policy = rcu_dereference(selinux_state.policy);
 248         mls_enabled = policy->policydb.mls_enabled;
 249         rcu_read_unlock();
 250         return mls_enabled;
 251 }
 252
 253 /*
 254  * Return the boolean value of a constraint expression
 255  * when it is applied to the specified source and target
 256  * security contexts.
 257  *
 258  * xcontext is a special beast...  It is used by the validatetrans rules
 259  * only.  For these rules, scontext is the context before the transition,
 260  * tcontext is the context after the transition, and xcontext is the context
 261  * of the process performing the transition.  All other callers of
 262  * constraint_expr_eval should pass in NULL for xcontext.
 263  */
 264 static int constraint_expr_eval(struct policydb *policydb,
 265                                 struct context *scontext,
 266                                 struct context *tcontext,
 267                                 struct context *xcontext,
 268                                 struct constraint_expr *cexpr)
 269 {
 270         u32 val1, val2;
 271         struct context *c;
 272         struct role_datum *r1, *r2;
 273         struct mls_level *l1, *l2;
 274         struct constraint_expr *e;
 275         int s[CEXPR_MAXDEPTH];
 276         int sp = -1;
 277
 278         for (e = cexpr; e; e = e->next) {
 279                 switch (e->expr_type) {
 280                 case CEXPR_NOT:
 281                         BUG_ON(sp < 0);
 282                         s[sp] = !s[sp];
 283                         break;
 284                 case CEXPR_AND:
 285                         BUG_ON(sp < 1);
 286                         sp--;
 287                         s[sp] &= s[sp + 1];
 288                         break;
 289                 case CEXPR_OR:
 290                         BUG_ON(sp < 1);
 291                         sp--;
 292                         s[sp] |= s[sp + 1];
 293                         break;
 294                 case CEXPR_ATTR:
 295                         if (sp == (CEXPR_MAXDEPTH - 1))
 296                                 return 0;
 297                         switch (e->attr) {
 298                         case CEXPR_USER:
 299                                 val1 = scontext->user;
 300                                 val2 = tcontext->user;
 301                                 break;
 302                         case CEXPR_TYPE:
 303                                 val1 = scontext->type;
 304                                 val2 = tcontext->type;
 305                                 break;
 306                         case CEXPR_ROLE:
 307                                 val1 = scontext->role;
 308                                 val2 = tcontext->role;
 309                                 r1 = policydb->role_val_to_struct[val1 - 1];
 310                                 r2 = policydb->role_val_to_struct[val2 - 1];
 311                                 switch (e->op) {
 312                                 case CEXPR_DOM:
 313                                         s[++sp] = ebitmap_get_bit(&r1->dominates,
 314                                                                   val2 - 1);
 315                                         continue;
 316                                 case CEXPR_DOMBY:
 317                                         s[++sp] = ebitmap_get_bit(&r2->dominates,
 318                                                                   val1 - 1);
 319                                         continue;
 320                                 case CEXPR_INCOMP:
 321                                         s[++sp] = (!ebitmap_get_bit(&r1->dominates,
 322                                                                     val2 - 1) &&
 323                                                    !ebitmap_get_bit(&r2->dominates,
 324                                                                     val1 - 1));
 325                                         continue;
 326                                 default:
 327                                         break;
 328                                 }
 329                                 break;
 330                         case CEXPR_L1L2:
 331                                 l1 = &(scontext->range.level[0]);
 332                                 l2 = &(tcontext->range.level[0]);
 333                                 goto mls_ops;
 334                         case CEXPR_L1H2:
 335                                 l1 = &(scontext->range.level[0]);
 336                                 l2 = &(tcontext->range.level[1]);
 337                                 goto mls_ops;
 338                         case CEXPR_H1L2:
 339                                 l1 = &(scontext->range.level[1]);
 340                                 l2 = &(tcontext->range.level[0]);
 341                                 goto mls_ops;
 342                         case CEXPR_H1H2:
 343                                 l1 = &(scontext->range.level[1]);
 344                                 l2 = &(tcontext->range.level[1]);
 345                                 goto mls_ops;
 346                         case CEXPR_L1H1:
 347                                 l1 = &(scontext->range.level[0]);
 348                                 l2 = &(scontext->range.level[1]);
 349                                 goto mls_ops;
 350                         case CEXPR_L2H2:
 351                                 l1 = &(tcontext->range.level[0]);
 352                                 l2 = &(tcontext->range.level[1]);
 353                                 goto mls_ops;
 354 mls_ops:
 355                                 switch (e->op) {
 356                                 case CEXPR_EQ:
 357                                         s[++sp] = mls_level_eq(l1, l2);
 358                                         continue;
 359                                 case CEXPR_NEQ:
 360                                         s[++sp] = !mls_level_eq(l1, l2);
 361                                         continue;
 362                                 case CEXPR_DOM:
 363                                         s[++sp] = mls_level_dom(l1, l2);
 364                                         continue;
 365                                 case CEXPR_DOMBY:
 366                                         s[++sp] = mls_level_dom(l2, l1);
 367                                         continue;
 368                                 case CEXPR_INCOMP:
 369                                         s[++sp] = mls_level_incomp(l2, l1);
 370                                         continue;
 371                                 default:
 372                                         BUG();
 373                                         return 0;
 374                                 }
 375                                 break;
 376                         default:
 377                                 BUG();
 378                                 return 0;
 379                         }
 380
 381                         switch (e->op) {
 382                         case CEXPR_EQ:
 383                                 s[++sp] = (val1 == val2);
 384                                 break;
 385                         case CEXPR_NEQ:
 386                                 s[++sp] = (val1 != val2);
 387                                 break;
 388                         default:
 389                                 BUG();
 390                                 return 0;
 391                         }
 392                         break;
 393                 case CEXPR_NAMES:
 394                         if (sp == (CEXPR_MAXDEPTH-1))
 395                                 return 0;
 396                         c = scontext;
 397                         if (e->attr & CEXPR_TARGET)
 398                                 c = tcontext;
 399                         else if (e->attr & CEXPR_XTARGET) {
 400                                 c = xcontext;
 401                                 if (!c) {
 402                                         BUG();
 403                                         return 0;
 404                                 }
 405                         }
 406                         if (e->attr & CEXPR_USER)
 407                                 val1 = c->user;
 408                         else if (e->attr & CEXPR_ROLE)
 409                                 val1 = c->role;
 410                         else if (e->attr & CEXPR_TYPE)
 411                                 val1 = c->type;
 412                         else {
 413                                 BUG();
 414                                 return 0;
 415                         }
 416
 417                         switch (e->op) {
 418                         case CEXPR_EQ:
 419                                 s[++sp] = ebitmap_get_bit(&e->names, val1 - 1);
 420                                 break;
 421                         case CEXPR_NEQ:
 422                                 s[++sp] = !ebitmap_get_bit(&e->names, val1 - 1);
 423                                 break;
 424                         default:
 425                                 BUG();
 426                                 return 0;
 427                         }
 428                         break;
 429                 default:
 430                         BUG();
 431                         return 0;
 432                 }
 433         }
 434
 435         BUG_ON(sp != 0);
 436         return s[0];
 437 }
 438
 439 /*
 440  * security_dump_masked_av - dumps masked permissions during
 441  * security_compute_av due to RBAC, MLS/Constraint and Type bounds.
 442  */
 443 static int dump_masked_av_helper(void *k, void *d, void *args)
 444 {
 445         struct perm_datum *pdatum = d;
 446         char **permission_names = args;
 447
 448         BUG_ON(pdatum->value < 1 || pdatum->value > 32);
 449
 450         permission_names[pdatum->value - 1] = (char *)k;
 451
 452         return 0;
 453 }
 454
 455 static void security_dump_masked_av(struct policydb *policydb,
 456                                     struct context *scontext,
 457                                     struct context *tcontext,
 458                                     u16 tclass,
 459                                     u32 permissions,
 460                                     const char *reason)
 461 {
 462         struct common_datum *common_dat;
 463         struct class_datum *tclass_dat;
 464         struct audit_buffer *ab;
 465         char *tclass_name;
 466         char *scontext_name = NULL;
 467         char *tcontext_name = NULL;
 468         char *permission_names[32];
 469         int index;
 470         u32 length;
 471         bool need_comma = false;
 472
 473         if (!permissions)
 474                 return;
 475
 476         tclass_name = sym_name(policydb, SYM_CLASSES, tclass - 1);
 477         tclass_dat = policydb->class_val_to_struct[tclass - 1];
 478         common_dat = tclass_dat->comdatum;
 479
 480         /* init permission_names */
 481         if (common_dat &&
 482             hashtab_map(&common_dat->permissions.table,
 483                         dump_masked_av_helper, permission_names) < 0)
 484                 goto out;
 485
 486         if (hashtab_map(&tclass_dat->permissions.table,
 487                         dump_masked_av_helper, permission_names) < 0)
 488                 goto out;
 489
 490         /* get scontext/tcontext in text form */
 491         if (context_struct_to_string(policydb, scontext,
 492                                      &scontext_name, &length) < 0)
 493                 goto out;
 494
 495         if (context_struct_to_string(policydb, tcontext,
 496                                      &tcontext_name, &length) < 0)
 497                 goto out;
 498
 499         /* audit a message */
 500         ab = audit_log_start(audit_context(),
 501                              GFP_ATOMIC, AUDIT_SELINUX_ERR);
 502         if (!ab)
 503                 goto out;
 504
 505         audit_log_format(ab, "op=security_compute_av reason=%s "
 506                          "scontext=%s tcontext=%s tclass=%s perms=",
 507                          reason, scontext_name, tcontext_name, tclass_name);
 508
 509         for (index = 0; index < 32; index++) {
 510                 u32 mask = (1 << index);
 511
 512                 if ((mask & permissions) == 0)
 513                         continue;
 514
 515                 audit_log_format(ab, "%s%s",
 516                                  need_comma ? "," : "",
 517                                  permission_names[index]
 518                                  ? permission_names[index] : "????");
 519                 need_comma = true;
 520         }
 521         audit_log_end(ab);
 522 out:
 523         /* release scontext/tcontext */
 524         kfree(tcontext_name);
 525         kfree(scontext_name);
 526 }
 527
 528 /*
 529  * security_boundary_permission - drops violated permissions
 530  * on boundary constraint.
 531  */
 532 static void type_attribute_bounds_av(struct policydb *policydb,
 533                                      struct context *scontext,
 534                                      struct context *tcontext,
 535                                      u16 tclass,
 536                                      struct av_decision *avd)
 537 {
 538         struct context lo_scontext;
 539         struct context lo_tcontext, *tcontextp = tcontext;
 540         struct av_decision lo_avd;
 541         struct type_datum *source;
 542         struct type_datum *target;
 543         u32 masked = 0;
 544
 545         source = policydb->type_val_to_struct[scontext->type - 1];
 546         BUG_ON(!source);
 547
 548         if (!source->bounds)
 549                 return;
 550
 551         target = policydb->type_val_to_struct[tcontext->type - 1];
 552         BUG_ON(!target);
 553
 554         memset(&lo_avd, 0, sizeof(lo_avd));
 555
 556         memcpy(&lo_scontext, scontext, sizeof(lo_scontext));
 557         lo_scontext.type = source->bounds;
 558
 559         if (target->bounds) {
 560                 memcpy(&lo_tcontext, tcontext, sizeof(lo_tcontext));
 561                 lo_tcontext.type = target->bounds;
 562                 tcontextp = &lo_tcontext;
 563         }
 564
 565         context_struct_compute_av(policydb, &lo_scontext,
 566                                   tcontextp,
 567                                   tclass,
 568                                   &lo_avd,
 569                                   NULL);
 570
 571         masked = ~lo_avd.allowed & avd->allowed;
 572
 573         if (likely(!masked))
 574                 return;         /* no masked permission */
 575
 576         /* mask violated permissions */
 577         avd->allowed &= ~masked;
 578
 579         /* audit masked permissions */
 580         security_dump_masked_av(policydb, scontext, tcontext,
 581                                 tclass, masked, "bounds");
 582 }
 583
 584 /*
 585  * flag which drivers have permissions
 586  * only looking for ioctl based extended permissions
 587  */
 588 void services_compute_xperms_drivers(
 589                 struct extended_perms *xperms,
 590                 struct avtab_node *node)
 591 {
 592         unsigned int i;
 593
 594         if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
 595                 /* if one or more driver has all permissions allowed */
 596                 for (i = 0; i < ARRAY_SIZE(xperms->drivers.p); i++)
 597                         xperms->drivers.p[i] |= node->datum.u.xperms->perms.p[i];
 598         } else if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
 599                 /* if allowing permissions within a driver */
 600                 security_xperm_set(xperms->drivers.p,
 601                                         node->datum.u.xperms->driver);
 602         }
 603
 604         xperms->len = 1;
 605 }
 606
 607 /*
 608  * Compute access vectors and extended permissions based on a context
 609  * structure pair for the permissions in a particular class.
 610  */
 611 static void context_struct_compute_av(struct policydb *policydb,
 612                                       struct context *scontext,
 613                                       struct context *tcontext,
 614                                       u16 tclass,
 615                                       struct av_decision *avd,
 616                                       struct extended_perms *xperms)
 617 {
 618         struct constraint_node *constraint;
 619         struct role_allow *ra;
 620         struct avtab_key avkey;
 621         struct avtab_node *node;
 622         struct class_datum *tclass_datum;
 623         struct ebitmap *sattr, *tattr;
 624         struct ebitmap_node *snode, *tnode;
 625         unsigned int i, j;
 626
 627         avd->allowed = 0;
 628         avd->auditallow = 0;
 629         avd->auditdeny = 0xffffffff;
 630         if (xperms) {
 631                 memset(&xperms->drivers, 0, sizeof(xperms->drivers));
 632                 xperms->len = 0;
 633         }
 634
 635         if (unlikely(!tclass || tclass > policydb->p_classes.nprim)) {
 636                 if (printk_ratelimit())
 637                         pr_warn("SELinux:  Invalid class %hu\n", tclass);
 638                 return;
 639         }
 640
 641         tclass_datum = policydb->class_val_to_struct[tclass - 1];
 642
 643         /*
 644          * If a specific type enforcement rule was defined for
 645          * this permission check, then use it.
 646          */
 647         avkey.target_class = tclass;
 648         avkey.specified = AVTAB_AV | AVTAB_XPERMS;
 649         sattr = &policydb->type_attr_map_array[scontext->type - 1];
 650         tattr = &policydb->type_attr_map_array[tcontext->type - 1];
 651         ebitmap_for_each_positive_bit(sattr, snode, i) {
 652                 ebitmap_for_each_positive_bit(tattr, tnode, j) {
 653                         avkey.source_type = i + 1;
 654                         avkey.target_type = j + 1;
 655                         for (node = avtab_search_node(&policydb->te_avtab,
 656                                                       &avkey);
 657                              node;
 658                              node = avtab_search_node_next(node, avkey.specified)) {
 659                                 if (node->key.specified == AVTAB_ALLOWED)
 660                                         avd->allowed |= node->datum.u.data;
 661                                 else if (node->key.specified == AVTAB_AUDITALLOW)
 662                                         avd->auditallow |= node->datum.u.data;
 663                                 else if (node->key.specified == AVTAB_AUDITDENY)
 664                                         avd->auditdeny &= node->datum.u.data;
 665                                 else if (xperms && (node->key.specified & AVTAB_XPERMS))
 666                                         services_compute_xperms_drivers(xperms, node);
 667                         }
 668
 669                         /* Check conditional av table for additional permissions */
 670                         cond_compute_av(&policydb->te_cond_avtab, &avkey,
 671                                         avd, xperms);
 672
 673                 }
 674         }
 675
 676         /*
 677          * Remove any permissions prohibited by a constraint (this includes
 678          * the MLS policy).
 679          */
 680         constraint = tclass_datum->constraints;
 681         while (constraint) {
 682                 if ((constraint->permissions & (avd->allowed)) &&
 683                     !constraint_expr_eval(policydb, scontext, tcontext, NULL,
 684                                           constraint->expr)) {
 685                         avd->allowed &= ~(constraint->permissions);
 686                 }
 687                 constraint = constraint->next;
 688         }
 689
 690         /*
 691          * If checking process transition permission and the
 692          * role is changing, then check the (current_role, new_role)
 693          * pair.
 694          */
 695         if (tclass == policydb->process_class &&
 696             (avd->allowed & policydb->process_trans_perms) &&
 697             scontext->role != tcontext->role) {
 698                 for (ra = policydb->role_allow; ra; ra = ra->next) {
 699                         if (scontext->role == ra->role &&
 700                             tcontext->role == ra->new_role)
 701                                 break;
 702                 }
 703                 if (!ra)
 704                         avd->allowed &= ~policydb->process_trans_perms;
 705         }
 706
 707         /*
 708          * If the given source and target types have boundary
 709          * constraint, lazy checks have to mask any violated
 710          * permission and notice it to userspace via audit.
 711          */
 712         type_attribute_bounds_av(policydb, scontext, tcontext,
 713                                  tclass, avd);
 714 }
 715
 716 static int security_validtrans_handle_fail(struct selinux_policy *policy,
 717                                         struct sidtab_entry *oentry,
 718                                         struct sidtab_entry *nentry,
 719                                         struct sidtab_entry *tentry,
 720                                         u16 tclass)
 721 {
 722         struct policydb *p = &policy->policydb;
 723         struct sidtab *sidtab = policy->sidtab;
 724         char *o = NULL, *n = NULL, *t = NULL;
 725         u32 olen, nlen, tlen;
 726
 727         if (sidtab_entry_to_string(p, sidtab, oentry, &o, &olen))
 728                 goto out;
 729         if (sidtab_entry_to_string(p, sidtab, nentry, &n, &nlen))
 730                 goto out;
 731         if (sidtab_entry_to_string(p, sidtab, tentry, &t, &tlen))
 732                 goto out;
 733         audit_log(audit_context(), GFP_ATOMIC, AUDIT_SELINUX_ERR,
 734                   "op=security_validate_transition seresult=denied"
 735                   " oldcontext=%s newcontext=%s taskcontext=%s tclass=%s",
 736                   o, n, t, sym_name(p, SYM_CLASSES, tclass-1));
 737 out:
 738         kfree(o);
 739         kfree(n);
 740         kfree(t);
 741
 742         if (!enforcing_enabled())
 743                 return 0;
 744         return -EPERM;
 745 }
 746
 747 static int security_compute_validatetrans(u32 oldsid, u32 newsid, u32 tasksid,
 748                                           u16 orig_tclass, bool user)
 749 {
 750         struct selinux_policy *policy;
 751         struct policydb *policydb;
 752         struct sidtab *sidtab;
 753         struct sidtab_entry *oentry;
 754         struct sidtab_entry *nentry;
 755         struct sidtab_entry *tentry;
 756         struct class_datum *tclass_datum;
 757         struct constraint_node *constraint;
 758         u16 tclass;
 759         int rc = 0;
 760
 761
 762         if (!selinux_initialized())
 763                 return 0;
 764
 765         rcu_read_lock();
 766
 767         policy = rcu_dereference(selinux_state.policy);
 768         policydb = &policy->policydb;
 769         sidtab = policy->sidtab;
 770
 771         if (!user)
 772                 tclass = unmap_class(&policy->map, orig_tclass);
 773         else
 774                 tclass = orig_tclass;
 775
 776         if (!tclass || tclass > policydb->p_classes.nprim) {
 777                 rc = -EINVAL;
 778                 goto out;
 779         }
 780         tclass_datum = policydb->class_val_to_struct[tclass - 1];
 781
 782         oentry = sidtab_search_entry(sidtab, oldsid);
 783         if (!oentry) {
 784                 pr_err("SELinux: %s:  unrecognized SID %d\n",
 785                         __func__, oldsid);
 786                 rc = -EINVAL;
 787                 goto out;
 788         }
 789
 790         nentry = sidtab_search_entry(sidtab, newsid);
 791         if (!nentry) {
 792                 pr_err("SELinux: %s:  unrecognized SID %d\n",
 793                         __func__, newsid);
 794                 rc = -EINVAL;
 795                 goto out;
 796         }
 797
 798         tentry = sidtab_search_entry(sidtab, tasksid);
 799         if (!tentry) {
 800                 pr_err("SELinux: %s:  unrecognized SID %d\n",
 801                         __func__, tasksid);
 802                 rc = -EINVAL;
 803                 goto out;
 804         }
 805
 806         constraint = tclass_datum->validatetrans;
 807         while (constraint) {
 808                 if (!constraint_expr_eval(policydb, &oentry->context,
 809                                           &nentry->context, &tentry->context,
 810                                           constraint->expr)) {
 811                         if (user)
 812                                 rc = -EPERM;
 813                         else
 814                                 rc = security_validtrans_handle_fail(policy,
 815                                                                 oentry,
 816                                                                 nentry,
 817                                                                 tentry,
 818                                                                 tclass);
 819                         goto out;
 820                 }
 821                 constraint = constraint->next;
 822         }
 823
 824 out:
 825         rcu_read_unlock();
 826         return rc;
 827 }
 828
 829 int security_validate_transition_user(u32 oldsid, u32 newsid, u32 tasksid,
 830                                       u16 tclass)
 831 {
 832         return security_compute_validatetrans(oldsid, newsid, tasksid,
 833                                               tclass, true);
 834 }
 835
 836 int security_validate_transition(u32 oldsid, u32 newsid, u32 tasksid,
 837                                  u16 orig_tclass)
 838 {
 839         return security_compute_validatetrans(oldsid, newsid, tasksid,
 840                                               orig_tclass, false);
 841 }
 842
 843 /*
 844  * security_bounded_transition - check whether the given
 845  * transition is directed to bounded, or not.
 846  * It returns 0, if @newsid is bounded by @oldsid.
 847  * Otherwise, it returns error code.
 848  *
 849  * @oldsid : current security identifier
 850  * @newsid : destinated security identifier
 851  */
 852 int security_bounded_transition(u32 old_sid, u32 new_sid)
 853 {
 854         struct selinux_policy *policy;
 855         struct policydb *policydb;
 856         struct sidtab *sidtab;
 857         struct sidtab_entry *old_entry, *new_entry;
 858         struct type_datum *type;
 859         u32 index;
 860         int rc;
 861
 862         if (!selinux_initialized())
 863                 return 0;
 864
 865         rcu_read_lock();
 866         policy = rcu_dereference(selinux_state.policy);
 867         policydb = &policy->policydb;
 868         sidtab = policy->sidtab;
 869
 870         rc = -EINVAL;
 871         old_entry = sidtab_search_entry(sidtab, old_sid);
 872         if (!old_entry) {
 873                 pr_err("SELinux: %s: unrecognized SID %u\n",
 874                        __func__, old_sid);
 875                 goto out;
 876         }
 877
 878         rc = -EINVAL;
 879         new_entry = sidtab_search_entry(sidtab, new_sid);
 880         if (!new_entry) {
 881                 pr_err("SELinux: %s: unrecognized SID %u\n",
 882                        __func__, new_sid);
 883                 goto out;
 884         }
 885
 886         rc = 0;
 887         /* type/domain unchanged */
 888         if (old_entry->context.type == new_entry->context.type)
 889                 goto out;
 890
 891         index = new_entry->context.type;
 892         while (true) {
 893                 type = policydb->type_val_to_struct[index - 1];
 894                 BUG_ON(!type);
 895
 896                 /* not bounded anymore */
 897                 rc = -EPERM;
 898                 if (!type->bounds)
 899                         break;
 900
 901                 /* @newsid is bounded by @oldsid */
 902                 rc = 0;
 903                 if (type->bounds == old_entry->context.type)
 904                         break;
 905
 906                 index = type->bounds;
 907         }
 908
 909         if (rc) {
 910                 char *old_name = NULL;
 911                 char *new_name = NULL;
 912                 u32 length;
 913
 914                 if (!sidtab_entry_to_string(policydb, sidtab, old_entry,
 915                                             &old_name, &length) &&
 916                     !sidtab_entry_to_string(policydb, sidtab, new_entry,
 917                                             &new_name, &length)) {
 918                         audit_log(audit_context(),
 919                                   GFP_ATOMIC, AUDIT_SELINUX_ERR,
 920                                   "op=security_bounded_transition "
 921                                   "seresult=denied "
 922                                   "oldcontext=%s newcontext=%s",
 923                                   old_name, new_name);
 924                 }
 925                 kfree(new_name);
 926                 kfree(old_name);
 927         }
 928 out:
 929         rcu_read_unlock();
 930
 931         return rc;
 932 }
 933
 934 static void avd_init(struct selinux_policy *policy, struct av_decision *avd)
 935 {
 936         avd->allowed = 0;
 937         avd->auditallow = 0;
 938         avd->auditdeny = 0xffffffff;
 939         if (policy)
 940                 avd->seqno = policy->latest_granting;
 941         else
 942                 avd->seqno = 0;
 943         avd->flags = 0;
 944 }
 945
 946 void services_compute_xperms_decision(struct extended_perms_decision *xpermd,
 947                                         struct avtab_node *node)
 948 {
 949         unsigned int i;
 950
 951         if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
 952                 if (xpermd->driver != node->datum.u.xperms->driver)
 953                         return;
 954         } else if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
 955                 if (!security_xperm_test(node->datum.u.xperms->perms.p,
 956                                         xpermd->driver))
 957                         return;
 958         } else {
 959                 BUG();
 960         }
 961
 962         if (node->key.specified == AVTAB_XPERMS_ALLOWED) {
 963                 xpermd->used |= XPERMS_ALLOWED;
 964                 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
 965                         memset(xpermd->allowed->p, 0xff,
 966                                         sizeof(xpermd->allowed->p));
 967                 }
 968                 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
 969                         for (i = 0; i < ARRAY_SIZE(xpermd->allowed->p); i++)
 970                                 xpermd->allowed->p[i] |=
 971                                         node->datum.u.xperms->perms.p[i];
 972                 }
 973         } else if (node->key.specified == AVTAB_XPERMS_AUDITALLOW) {
 974                 xpermd->used |= XPERMS_AUDITALLOW;
 975                 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
 976                         memset(xpermd->auditallow->p, 0xff,
 977                                         sizeof(xpermd->auditallow->p));
 978                 }
 979                 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
 980                         for (i = 0; i < ARRAY_SIZE(xpermd->auditallow->p); i++)
 981                                 xpermd->auditallow->p[i] |=
 982                                         node->datum.u.xperms->perms.p[i];
 983                 }
 984         } else if (node->key.specified == AVTAB_XPERMS_DONTAUDIT) {
 985                 xpermd->used |= XPERMS_DONTAUDIT;
 986                 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
 987                         memset(xpermd->dontaudit->p, 0xff,
 988                                         sizeof(xpermd->dontaudit->p));
 989                 }
 990                 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
 991                         for (i = 0; i < ARRAY_SIZE(xpermd->dontaudit->p); i++)
 992                                 xpermd->dontaudit->p[i] |=
 993                                         node->datum.u.xperms->perms.p[i];
 994                 }
 995         } else {
 996                 BUG();
 997         }
 998 }
 999
1000 void security_compute_xperms_decision(u32 ssid,
1001                                       u32 tsid,
1002                                       u16 orig_tclass,
1003                                       u8 driver,
1004                                       struct extended_perms_decision *xpermd)
1005 {
1006         struct selinux_policy *policy;
1007         struct policydb *policydb;
1008         struct sidtab *sidtab;
1009         u16 tclass;
1010         struct context *scontext, *tcontext;
1011         struct avtab_key avkey;
1012         struct avtab_node *node;
1013         struct ebitmap *sattr, *tattr;
1014         struct ebitmap_node *snode, *tnode;
1015         unsigned int i, j;
1016
1017         xpermd->driver = driver;
1018         xpermd->used = 0;
1019         memset(xpermd->allowed->p, 0, sizeof(xpermd->allowed->p));
1020         memset(xpermd->auditallow->p, 0, sizeof(xpermd->auditallow->p));
1021         memset(xpermd->dontaudit->p, 0, sizeof(xpermd->dontaudit->p));
1022
1023         rcu_read_lock();
1024         if (!selinux_initialized())
1025                 goto allow;
1026
1027         policy = rcu_dereference(selinux_state.policy);
1028         policydb = &policy->policydb;
1029         sidtab = policy->sidtab;
1030
1031         scontext = sidtab_search(sidtab, ssid);
1032         if (!scontext) {
1033                 pr_err("SELinux: %s:  unrecognized SID %d\n",
1034                        __func__, ssid);
1035                 goto out;
1036         }
1037
1038         tcontext = sidtab_search(sidtab, tsid);
1039         if (!tcontext) {
1040                 pr_err("SELinux: %s:  unrecognized SID %d\n",
1041                        __func__, tsid);
1042                 goto out;
1043         }
1044
1045         tclass = unmap_class(&policy->map, orig_tclass);
1046         if (unlikely(orig_tclass && !tclass)) {
1047                 if (policydb->allow_unknown)
1048                         goto allow;
1049                 goto out;
1050         }
1051
1052
1053         if (unlikely(!tclass || tclass > policydb->p_classes.nprim)) {
1054                 pr_warn_ratelimited("SELinux:  Invalid class %hu\n", tclass);
1055                 goto out;
1056         }
1057
1058         avkey.target_class = tclass;
1059         avkey.specified = AVTAB_XPERMS;
1060         sattr = &policydb->type_attr_map_array[scontext->type - 1];
1061         tattr = &policydb->type_attr_map_array[tcontext->type - 1];
1062         ebitmap_for_each_positive_bit(sattr, snode, i) {
1063                 ebitmap_for_each_positive_bit(tattr, tnode, j) {
1064                         avkey.source_type = i + 1;
1065                         avkey.target_type = j + 1;
1066                         for (node = avtab_search_node(&policydb->te_avtab,
1067                                                       &avkey);
1068                              node;
1069                              node = avtab_search_node_next(node, avkey.specified))
1070                                 services_compute_xperms_decision(xpermd, node);
1071
1072                         cond_compute_xperms(&policydb->te_cond_avtab,
1073                                                 &avkey, xpermd);
1074                 }
1075         }
1076 out:
1077         rcu_read_unlock();
1078         return;
1079 allow:
1080         memset(xpermd->allowed->p, 0xff, sizeof(xpermd->allowed->p));
1081         goto out;
1082 }
1083
1084 /**
1085  * security_compute_av - Compute access vector decisions.
1086  * @ssid: source security identifier
1087  * @tsid: target security identifier
1088  * @orig_tclass: target security class
1089  * @avd: access vector decisions
1090  * @xperms: extended permissions
1091  *
1092  * Compute a set of access vector decisions based on the
1093  * SID pair (@ssid, @tsid) for the permissions in @tclass.
1094  */
1095 void security_compute_av(u32 ssid,
1096                          u32 tsid,
1097                          u16 orig_tclass,
1098                          struct av_decision *avd,
1099                          struct extended_perms *xperms)
1100 {
1101         struct selinux_policy *policy;
1102         struct policydb *policydb;
1103         struct sidtab *sidtab;
1104         u16 tclass;
1105         struct context *scontext = NULL, *tcontext = NULL;
1106
1107         rcu_read_lock();
1108         policy = rcu_dereference(selinux_state.policy);
1109         avd_init(policy, avd);
1110         xperms->len = 0;
1111         if (!selinux_initialized())
1112                 goto allow;
1113
1114         policydb = &policy->policydb;
1115         sidtab = policy->sidtab;
1116
1117         scontext = sidtab_search(sidtab, ssid);
1118         if (!scontext) {
1119                 pr_err("SELinux: %s:  unrecognized SID %d\n",
1120                        __func__, ssid);
1121                 goto out;
1122         }
1123
1124         /* permissive domain? */
1125         if (ebitmap_get_bit(&policydb->permissive_map, scontext->type))
1126                 avd->flags |= AVD_FLAGS_PERMISSIVE;
1127
1128         tcontext = sidtab_search(sidtab, tsid);
1129         if (!tcontext) {
1130                 pr_err("SELinux: %s:  unrecognized SID %d\n",
1131                        __func__, tsid);
1132                 goto out;
1133         }
1134
1135         tclass = unmap_class(&policy->map, orig_tclass);
1136         if (unlikely(orig_tclass && !tclass)) {
1137                 if (policydb->allow_unknown)
1138                         goto allow;
1139                 goto out;
1140         }
1141         context_struct_compute_av(policydb, scontext, tcontext, tclass, avd,
1142                                   xperms);
1143         map_decision(&policy->map, orig_tclass, avd,
1144                      policydb->allow_unknown);
1145 out:
1146         rcu_read_unlock();
1147         return;
1148 allow:
1149         avd->allowed = 0xffffffff;
1150         goto out;
1151 }
1152
1153 void security_compute_av_user(u32 ssid,
1154                               u32 tsid,
1155                               u16 tclass,
1156                               struct av_decision *avd)
1157 {
1158         struct selinux_policy *policy;
1159         struct policydb *policydb;
1160         struct sidtab *sidtab;
1161         struct context *scontext = NULL, *tcontext = NULL;
1162
1163         rcu_read_lock();
1164         policy = rcu_dereference(selinux_state.policy);
1165         avd_init(policy, avd);
1166         if (!selinux_initialized())
1167                 goto allow;
1168
1169         policydb = &policy->policydb;
1170         sidtab = policy->sidtab;
1171
1172         scontext = sidtab_search(sidtab, ssid);
1173         if (!scontext) {
1174                 pr_err("SELinux: %s:  unrecognized SID %d\n",
1175                        __func__, ssid);
1176                 goto out;
1177         }
1178
1179         /* permissive domain? */
1180         if (ebitmap_get_bit(&policydb->permissive_map, scontext->type))
1181                 avd->flags |= AVD_FLAGS_PERMISSIVE;
1182
1183         tcontext = sidtab_search(sidtab, tsid);
1184         if (!tcontext) {
1185                 pr_err("SELinux: %s:  unrecognized SID %d\n",
1186                        __func__, tsid);
1187                 goto out;
1188         }
1189
1190         if (unlikely(!tclass)) {
1191                 if (policydb->allow_unknown)
1192                         goto allow;
1193                 goto out;
1194         }
1195
1196         context_struct_compute_av(policydb, scontext, tcontext, tclass, avd,
1197                                   NULL);
1198  out:
1199         rcu_read_unlock();
1200         return;
1201 allow:
1202         avd->allowed = 0xffffffff;
1203         goto out;
1204 }
1205
1206 /*
1207  * Write the security context string representation of
1208  * the context structure `context' into a dynamically
1209  * allocated string of the correct size.  Set `*scontext'
1210  * to point to this string and set `*scontext_len' to
1211  * the length of the string.
1212  */
1213 static int context_struct_to_string(struct policydb *p,
1214                                     struct context *context,
1215                                     char **scontext, u32 *scontext_len)
1216 {
1217         char *scontextp;
1218
1219         if (scontext)
1220                 *scontext = NULL;
1221         *scontext_len = 0;
1222
1223         if (context->len) {
1224                 *scontext_len = context->len;
1225                 if (scontext) {
1226                         *scontext = kstrdup(context->str, GFP_ATOMIC);
1227                         if (!(*scontext))
1228                                 return -ENOMEM;
1229                 }
1230                 return 0;
1231         }
1232
1233         /* Compute the size of the context. */
1234         *scontext_len += strlen(sym_name(p, SYM_USERS, context->user - 1)) + 1;
1235         *scontext_len += strlen(sym_name(p, SYM_ROLES, context->role - 1)) + 1;
1236         *scontext_len += strlen(sym_name(p, SYM_TYPES, context->type - 1)) + 1;
1237         *scontext_len += mls_compute_context_len(p, context);
1238
1239         if (!scontext)
1240                 return 0;
1241
1242         /* Allocate space for the context; caller must free this space. */
1243         scontextp = kmalloc(*scontext_len, GFP_ATOMIC);
1244         if (!scontextp)
1245                 return -ENOMEM;
1246         *scontext = scontextp;
1247
1248         /*
1249          * Copy the user name, role name and type name into the context.
1250          */
1251         scontextp += sprintf(scontextp, "%s:%s:%s",
1252                 sym_name(p, SYM_USERS, context->user - 1),
1253                 sym_name(p, SYM_ROLES, context->role - 1),
1254                 sym_name(p, SYM_TYPES, context->type - 1));
1255
1256         mls_sid_to_context(p, context, &scontextp);
1257
1258         *scontextp = 0;
1259
1260         return 0;
1261 }
1262
1263 static int sidtab_entry_to_string(struct policydb *p,
1264                                   struct sidtab *sidtab,
1265                                   struct sidtab_entry *entry,
1266                                   char **scontext, u32 *scontext_len)
1267 {
1268         int rc = sidtab_sid2str_get(sidtab, entry, scontext, scontext_len);
1269
1270         if (rc != -ENOENT)
1271                 return rc;
1272
1273         rc = context_struct_to_string(p, &entry->context, scontext,
1274                                       scontext_len);
1275         if (!rc && scontext)
1276                 sidtab_sid2str_put(sidtab, entry, *scontext, *scontext_len);
1277         return rc;
1278 }
1279
1280 #include "initial_sid_to_string.h"
1281
1282 int security_sidtab_hash_stats(char *page)
1283 {
1284         struct selinux_policy *policy;
1285         int rc;
1286
1287         if (!selinux_initialized()) {
1288                 pr_err("SELinux: %s:  called before initial load_policy\n",
1289                        __func__);
1290                 return -EINVAL;
1291         }
1292
1293         rcu_read_lock();
1294         policy = rcu_dereference(selinux_state.policy);
1295         rc = sidtab_hash_stats(policy->sidtab, page);
1296         rcu_read_unlock();
1297
1298         return rc;
1299 }
1300
1301 const char *security_get_initial_sid_context(u32 sid)
1302 {
1303         if (unlikely(sid > SECINITSID_NUM))
1304                 return NULL;
1305         return initial_sid_to_string[sid];
1306 }
1307
1308 static int security_sid_to_context_core(u32 sid, char **scontext,
1309                                         u32 *scontext_len, int force,
1310                                         int only_invalid)
1311 {
1312         struct selinux_policy *policy;
1313         struct policydb *policydb;
1314         struct sidtab *sidtab;
1315         struct sidtab_entry *entry;
1316         int rc = 0;
1317
1318         if (scontext)
1319                 *scontext = NULL;
1320         *scontext_len  = 0;
1321
1322         if (!selinux_initialized()) {
1323                 if (sid <= SECINITSID_NUM) {
1324                         char *scontextp;
1325                         const char *s;
1326
1327                         /*
1328                          * Before the policy is loaded, translate
1329                          * SECINITSID_INIT to "kernel", because systemd and
1330                          * libselinux < 2.6 take a getcon_raw() result that is
1331                          * both non-null and not "kernel" to mean that a policy
1332                          * is already loaded.
1333                          */
1334                         if (sid == SECINITSID_INIT)
1335                                 sid = SECINITSID_KERNEL;
1336
1337                         s = initial_sid_to_string[sid];
1338                         if (!s)
1339                                 return -EINVAL;
1340                         *scontext_len = strlen(s) + 1;
1341                         if (!scontext)
1342                                 return 0;
1343                         scontextp = kmemdup(s, *scontext_len, GFP_ATOMIC);
1344                         if (!scontextp)
1345                                 return -ENOMEM;
1346                         *scontext = scontextp;
1347                         return 0;
1348                 }
1349                 pr_err("SELinux: %s:  called before initial "
1350                        "load_policy on unknown SID %d\n", __func__, sid);
1351                 return -EINVAL;
1352         }
1353         rcu_read_lock();
1354         policy = rcu_dereference(selinux_state.policy);
1355         policydb = &policy->policydb;
1356         sidtab = policy->sidtab;
1357
1358         if (force)
1359                 entry = sidtab_search_entry_force(sidtab, sid);
1360         else
1361                 entry = sidtab_search_entry(sidtab, sid);
1362         if (!entry) {
1363                 pr_err("SELinux: %s:  unrecognized SID %d\n",
1364                         __func__, sid);
1365                 rc = -EINVAL;
1366                 goto out_unlock;
1367         }
1368         if (only_invalid && !entry->context.len)
1369                 goto out_unlock;
1370
1371         rc = sidtab_entry_to_string(policydb, sidtab, entry, scontext,
1372                                     scontext_len);
1373
1374 out_unlock:
1375         rcu_read_unlock();
1376         return rc;
1377
1378 }
1379
1380 /**
1381  * security_sid_to_context - Obtain a context for a given SID.
1382  * @sid: security identifier, SID
1383  * @scontext: security context
1384  * @scontext_len: length in bytes
1385  *
1386  * Write the string representation of the context associated with @sid
1387  * into a dynamically allocated string of the correct size.  Set @scontext
1388  * to point to this string and set @scontext_len to the length of the string.
1389  */
1390 int security_sid_to_context(u32 sid, char **scontext, u32 *scontext_len)
1391 {
1392         return security_sid_to_context_core(sid, scontext,
1393                                             scontext_len, 0, 0);
1394 }
1395
1396 int security_sid_to_context_force(u32 sid,
1397                                   char **scontext, u32 *scontext_len)
1398 {
1399         return security_sid_to_context_core(sid, scontext,
1400                                             scontext_len, 1, 0);
1401 }
1402
1403 /**
1404  * security_sid_to_context_inval - Obtain a context for a given SID if it
1405  *                                 is invalid.
1406  * @sid: security identifier, SID
1407  * @scontext: security context
1408  * @scontext_len: length in bytes
1409  *
1410  * Write the string representation of the context associated with @sid
1411  * into a dynamically allocated string of the correct size, but only if the
1412  * context is invalid in the current policy.  Set @scontext to point to
1413  * this string (or NULL if the context is valid) and set @scontext_len to
1414  * the length of the string (or 0 if the context is valid).
1415  */
1416 int security_sid_to_context_inval(u32 sid,
1417                                   char **scontext, u32 *scontext_len)
1418 {
1419         return security_sid_to_context_core(sid, scontext,
1420                                             scontext_len, 1, 1);
1421 }
1422
1423 /*
1424  * Caveat:  Mutates scontext.
1425  */
1426 static int string_to_context_struct(struct policydb *pol,
1427                                     struct sidtab *sidtabp,
1428                                     char *scontext,
1429                                     struct context *ctx,
1430                                     u32 def_sid)
1431 {
1432         struct role_datum *role;
1433         struct type_datum *typdatum;
1434         struct user_datum *usrdatum;
1435         char *scontextp, *p, oldc;
1436         int rc = 0;
1437
1438         context_init(ctx);
1439
1440         /* Parse the security context. */
1441
1442         rc = -EINVAL;
1443         scontextp = scontext;
1444
1445         /* Extract the user. */
1446         p = scontextp;
1447         while (*p && *p != ':')
1448                 p++;
1449
1450         if (*p == 0)
1451                 goto out;
1452
1453         *p++ = 0;
1454
1455         usrdatum = symtab_search(&pol->p_users, scontextp);
1456         if (!usrdatum)
1457                 goto out;
1458
1459         ctx->user = usrdatum->value;
1460
1461         /* Extract role. */
1462         scontextp = p;
1463         while (*p && *p != ':')
1464                 p++;
1465
1466         if (*p == 0)
1467                 goto out;
1468
1469         *p++ = 0;
1470
1471         role = symtab_search(&pol->p_roles, scontextp);
1472         if (!role)
1473                 goto out;
1474         ctx->role = role->value;
1475
1476         /* Extract type. */
1477         scontextp = p;
1478         while (*p && *p != ':')
1479                 p++;
1480         oldc = *p;
1481         *p++ = 0;
1482
1483         typdatum = symtab_search(&pol->p_types, scontextp);
1484         if (!typdatum || typdatum->attribute)
1485                 goto out;
1486
1487         ctx->type = typdatum->value;
1488
1489         rc = mls_context_to_sid(pol, oldc, p, ctx, sidtabp, def_sid);
1490         if (rc)
1491                 goto out;
1492
1493         /* Check the validity of the new context. */
1494         rc = -EINVAL;
1495         if (!policydb_context_isvalid(pol, ctx))
1496                 goto out;
1497         rc = 0;
1498 out:
1499         if (rc)
1500                 context_destroy(ctx);
1501         return rc;
1502 }
1503
1504 static int security_context_to_sid_core(const char *scontext, u32 scontext_len,
1505                                         u32 *sid, u32 def_sid, gfp_t gfp_flags,
1506                                         int force)
1507 {
1508         struct selinux_policy *policy;
1509         struct policydb *policydb;
1510         struct sidtab *sidtab;
1511         char *scontext2, *str = NULL;
1512         struct context context;
1513         int rc = 0;
1514
1515         /* An empty security context is never valid. */
1516         if (!scontext_len)
1517                 return -EINVAL;
1518
1519         /* Copy the string to allow changes and ensure a NUL terminator */
1520         scontext2 = kmemdup_nul(scontext, scontext_len, gfp_flags);
1521         if (!scontext2)
1522                 return -ENOMEM;
1523
1524         if (!selinux_initialized()) {
1525                 u32 i;
1526
1527                 for (i = 1; i < SECINITSID_NUM; i++) {
1528                         const char *s = initial_sid_to_string[i];
1529
1530                         if (s && !strcmp(s, scontext2)) {
1531                                 *sid = i;
1532                                 goto out;
1533                         }
1534                 }
1535                 *sid = SECINITSID_KERNEL;
1536                 goto out;
1537         }
1538         *sid = SECSID_NULL;
1539
1540         if (force) {
1541                 /* Save another copy for storing in uninterpreted form */
1542                 rc = -ENOMEM;
1543                 str = kstrdup(scontext2, gfp_flags);
1544                 if (!str)
1545                         goto out;
1546         }
1547 retry:
1548         rcu_read_lock();
1549         policy = rcu_dereference(selinux_state.policy);
1550         policydb = &policy->policydb;
1551         sidtab = policy->sidtab;
1552         rc = string_to_context_struct(policydb, sidtab, scontext2,
1553                                       &context, def_sid);
1554         if (rc == -EINVAL && force) {
1555                 context.str = str;
1556                 context.len = strlen(str) + 1;
1557                 str = NULL;
1558         } else if (rc)
1559                 goto out_unlock;
1560         rc = sidtab_context_to_sid(sidtab, &context, sid);
1561         if (rc == -ESTALE) {
1562                 rcu_read_unlock();
1563                 if (context.str) {
1564                         str = context.str;
1565                         context.str = NULL;
1566                 }
1567                 context_destroy(&context);
1568                 goto retry;
1569         }
1570         context_destroy(&context);
1571 out_unlock:
1572         rcu_read_unlock();
1573 out:
1574         kfree(scontext2);
1575         kfree(str);
1576         return rc;
1577 }
1578
1579 /**
1580  * security_context_to_sid - Obtain a SID for a given security context.
1581  * @scontext: security context
1582  * @scontext_len: length in bytes
1583  * @sid: security identifier, SID
1584  * @gfp: context for the allocation
1585  *
1586  * Obtains a SID associated with the security context that
1587  * has the string representation specified by @scontext.
1588  * Returns -%EINVAL if the context is invalid, -%ENOMEM if insufficient
1589  * memory is available, or 0 on success.
1590  */
1591 int security_context_to_sid(const char *scontext, u32 scontext_len, u32 *sid,
1592                             gfp_t gfp)
1593 {
1594         return security_context_to_sid_core(scontext, scontext_len,
1595                                             sid, SECSID_NULL, gfp, 0);
1596 }
1597
1598 int security_context_str_to_sid(const char *scontext, u32 *sid, gfp_t gfp)
1599 {
1600         return security_context_to_sid(scontext, strlen(scontext),
1601                                        sid, gfp);
1602 }
1603
1604 /**
1605  * security_context_to_sid_default - Obtain a SID for a given security context,
1606  * falling back to specified default if needed.
1607  *
1608  * @scontext: security context
1609  * @scontext_len: length in bytes
1610  * @sid: security identifier, SID
1611  * @def_sid: default SID to assign on error
1612  * @gfp_flags: the allocator get-free-page (GFP) flags
1613  *
1614  * Obtains a SID associated with the security context that
1615  * has the string representation specified by @scontext.
1616  * The default SID is passed to the MLS layer to be used to allow
1617  * kernel labeling of the MLS field if the MLS field is not present
1618  * (for upgrading to MLS without full relabel).
1619  * Implicitly forces adding of the context even if it cannot be mapped yet.
1620  * Returns -%EINVAL if the context is invalid, -%ENOMEM if insufficient
1621  * memory is available, or 0 on success.
1622  */
1623 int security_context_to_sid_default(const char *scontext, u32 scontext_len,
1624                                     u32 *sid, u32 def_sid, gfp_t gfp_flags)
1625 {
1626         return security_context_to_sid_core(scontext, scontext_len,
1627                                             sid, def_sid, gfp_flags, 1);
1628 }
1629
1630 int security_context_to_sid_force(const char *scontext, u32 scontext_len,
1631                                   u32 *sid)
1632 {
1633         return security_context_to_sid_core(scontext, scontext_len,
1634                                             sid, SECSID_NULL, GFP_KERNEL, 1);
1635 }
1636
1637 static int compute_sid_handle_invalid_context(
1638         struct selinux_policy *policy,
1639         struct sidtab_entry *sentry,
1640         struct sidtab_entry *tentry,
1641         u16 tclass,
1642         struct context *newcontext)
1643 {
1644         struct policydb *policydb = &policy->policydb;
1645         struct sidtab *sidtab = policy->sidtab;
1646         char *s = NULL, *t = NULL, *n = NULL;
1647         u32 slen, tlen, nlen;
1648         struct audit_buffer *ab;
1649
1650         if (sidtab_entry_to_string(policydb, sidtab, sentry, &s, &slen))
1651                 goto out;
1652         if (sidtab_entry_to_string(policydb, sidtab, tentry, &t, &tlen))
1653                 goto out;
1654         if (context_struct_to_string(policydb, newcontext, &n, &nlen))
1655                 goto out;
1656         ab = audit_log_start(audit_context(), GFP_ATOMIC, AUDIT_SELINUX_ERR);
1657         if (!ab)
1658                 goto out;
1659         audit_log_format(ab,
1660                          "op=security_compute_sid invalid_context=");
1661         /* no need to record the NUL with untrusted strings */
1662         audit_log_n_untrustedstring(ab, n, nlen - 1);
1663         audit_log_format(ab, " scontext=%s tcontext=%s tclass=%s",
1664                          s, t, sym_name(policydb, SYM_CLASSES, tclass-1));
1665         audit_log_end(ab);
1666 out:
1667         kfree(s);
1668         kfree(t);
1669         kfree(n);
1670         if (!enforcing_enabled())
1671                 return 0;
1672         return -EACCES;
1673 }
1674
1675 static void filename_compute_type(struct policydb *policydb,
1676                                   struct context *newcontext,
1677                                   u32 stype, u32 ttype, u16 tclass,
1678                                   const char *objname)
1679 {
1680         struct filename_trans_key ft;
1681         struct filename_trans_datum *datum;
1682
1683         /*
1684          * Most filename trans rules are going to live in specific directories
1685          * like /dev or /var/run.  This bitmap will quickly skip rule searches
1686          * if the ttype does not contain any rules.
1687          */
1688         if (!ebitmap_get_bit(&policydb->filename_trans_ttypes, ttype))
1689                 return;
1690
1691         ft.ttype = ttype;
1692         ft.tclass = tclass;
1693         ft.name = objname;
1694
1695         datum = policydb_filenametr_search(policydb, &ft);
1696         while (datum) {
1697                 if (ebitmap_get_bit(&datum->stypes, stype - 1)) {
1698                         newcontext->type = datum->otype;
1699                         return;
1700                 }
1701                 datum = datum->next;
1702         }
1703 }
1704
1705 static int security_compute_sid(u32 ssid,
1706                                 u32 tsid,
1707                                 u16 orig_tclass,
1708                                 u16 specified,
1709                                 const char *objname,
1710                                 u32 *out_sid,
1711                                 bool kern)
1712 {
1713         struct selinux_policy *policy;
1714         struct policydb *policydb;
1715         struct sidtab *sidtab;
1716         struct class_datum *cladatum;
1717         struct context *scontext, *tcontext, newcontext;
1718         struct sidtab_entry *sentry, *tentry;
1719         struct avtab_key avkey;
1720         struct avtab_node *avnode, *node;
1721         u16 tclass;
1722         int rc = 0;
1723         bool sock;
1724
1725         if (!selinux_initialized()) {
1726                 switch (orig_tclass) {
1727                 case SECCLASS_PROCESS: /* kernel value */
1728                         *out_sid = ssid;
1729                         break;
1730                 default:
1731                         *out_sid = tsid;
1732                         break;
1733                 }
1734                 goto out;
1735         }
1736
1737 retry:
1738         cladatum = NULL;
1739         context_init(&newcontext);
1740
1741         rcu_read_lock();
1742
1743         policy = rcu_dereference(selinux_state.policy);
1744
1745         if (kern) {
1746                 tclass = unmap_class(&policy->map, orig_tclass);
1747                 sock = security_is_socket_class(orig_tclass);
1748         } else {
1749                 tclass = orig_tclass;
1750                 sock = security_is_socket_class(map_class(&policy->map,
1751                                                           tclass));
1752         }
1753
1754         policydb = &policy->policydb;
1755         sidtab = policy->sidtab;
1756
1757         sentry = sidtab_search_entry(sidtab, ssid);
1758         if (!sentry) {
1759                 pr_err("SELinux: %s:  unrecognized SID %d\n",
1760                        __func__, ssid);
1761                 rc = -EINVAL;
1762                 goto out_unlock;
1763         }
1764         tentry = sidtab_search_entry(sidtab, tsid);
1765         if (!tentry) {
1766                 pr_err("SELinux: %s:  unrecognized SID %d\n",
1767                        __func__, tsid);
1768                 rc = -EINVAL;
1769                 goto out_unlock;
1770         }
1771
1772         scontext = &sentry->context;
1773         tcontext = &tentry->context;
1774
1775         if (tclass && tclass <= policydb->p_classes.nprim)
1776                 cladatum = policydb->class_val_to_struct[tclass - 1];
1777
1778         /* Set the user identity. */
1779         switch (specified) {
1780         case AVTAB_TRANSITION:
1781         case AVTAB_CHANGE:
1782                 if (cladatum && cladatum->default_user == DEFAULT_TARGET) {
1783                         newcontext.user = tcontext->user;
1784                 } else {
1785                         /* notice this gets both DEFAULT_SOURCE and unset */
1786                         /* Use the process user identity. */
1787                         newcontext.user = scontext->user;
1788                 }
1789                 break;
1790         case AVTAB_MEMBER:
1791                 /* Use the related object owner. */
1792                 newcontext.user = tcontext->user;
1793                 break;
1794         }
1795
1796         /* Set the role to default values. */
1797         if (cladatum && cladatum->default_role == DEFAULT_SOURCE) {
1798                 newcontext.role = scontext->role;
1799         } else if (cladatum && cladatum->default_role == DEFAULT_TARGET) {
1800                 newcontext.role = tcontext->role;
1801         } else {
1802                 if ((tclass == policydb->process_class) || sock)
1803                         newcontext.role = scontext->role;
1804                 else
1805                         newcontext.role = OBJECT_R_VAL;
1806         }
1807
1808         /* Set the type to default values. */
1809         if (cladatum && cladatum->default_type == DEFAULT_SOURCE) {
1810                 newcontext.type = scontext->type;
1811         } else if (cladatum && cladatum->default_type == DEFAULT_TARGET) {
1812                 newcontext.type = tcontext->type;
1813         } else {
1814                 if ((tclass == policydb->process_class) || sock) {
1815                         /* Use the type of process. */
1816                         newcontext.type = scontext->type;
1817                 } else {
1818                         /* Use the type of the related object. */
1819                         newcontext.type = tcontext->type;
1820                 }
1821         }
1822
1823         /* Look for a type transition/member/change rule. */
1824         avkey.source_type = scontext->type;
1825         avkey.target_type = tcontext->type;
1826         avkey.target_class = tclass;
1827         avkey.specified = specified;
1828         avnode = avtab_search_node(&policydb->te_avtab, &avkey);
1829
1830         /* If no permanent rule, also check for enabled conditional rules */
1831         if (!avnode) {
1832                 node = avtab_search_node(&policydb->te_cond_avtab, &avkey);
1833                 for (; node; node = avtab_search_node_next(node, specified)) {
1834                         if (node->key.specified & AVTAB_ENABLED) {
1835                                 avnode = node;
1836                                 break;
1837                         }
1838                 }
1839         }
1840
1841         if (avnode) {
1842                 /* Use the type from the type transition/member/change rule. */
1843                 newcontext.type = avnode->datum.u.data;
1844         }
1845
1846         /* if we have a objname this is a file trans check so check those rules */
1847         if (objname)
1848                 filename_compute_type(policydb, &newcontext, scontext->type,
1849                                       tcontext->type, tclass, objname);
1850
1851         /* Check for class-specific changes. */
1852         if (specified & AVTAB_TRANSITION) {
1853                 /* Look for a role transition rule. */
1854                 struct role_trans_datum *rtd;
1855                 struct role_trans_key rtk = {
1856                         .role = scontext->role,
1857                         .type = tcontext->type,
1858                         .tclass = tclass,
1859                 };
1860
1861                 rtd = policydb_roletr_search(policydb, &rtk);
1862                 if (rtd)
1863                         newcontext.role = rtd->new_role;
1864         }
1865
1866         /* Set the MLS attributes.
1867            This is done last because it may allocate memory. */
1868         rc = mls_compute_sid(policydb, scontext, tcontext, tclass, specified,
1869                              &newcontext, sock);
1870         if (rc)
1871                 goto out_unlock;
1872
1873         /* Check the validity of the context. */
1874         if (!policydb_context_isvalid(policydb, &newcontext)) {
1875                 rc = compute_sid_handle_invalid_context(policy, sentry,
1876                                                         tentry, tclass,
1877                                                         &newcontext);
1878                 if (rc)
1879                         goto out_unlock;
1880         }
1881         /* Obtain the sid for the context. */
1882         rc = sidtab_context_to_sid(sidtab, &newcontext, out_sid);
1883         if (rc == -ESTALE) {
1884                 rcu_read_unlock();
1885                 context_destroy(&newcontext);
1886                 goto retry;
1887         }
1888 out_unlock:
1889         rcu_read_unlock();
1890         context_destroy(&newcontext);
1891 out:
1892         return rc;
1893 }
1894
1895 /**
1896  * security_transition_sid - Compute the SID for a new subject/object.
1897  * @ssid: source security identifier
1898  * @tsid: target security identifier
1899  * @tclass: target security class
1900  * @qstr: object name
1901  * @out_sid: security identifier for new subject/object
1902  *
1903  * Compute a SID to use for labeling a new subject or object in the
1904  * class @tclass based on a SID pair (@ssid, @tsid).
1905  * Return -%EINVAL if any of the parameters are invalid, -%ENOMEM
1906  * if insufficient memory is available, or %0 if the new SID was
1907  * computed successfully.
1908  */
1909 int security_transition_sid(u32 ssid, u32 tsid, u16 tclass,
1910                             const struct qstr *qstr, u32 *out_sid)
1911 {
1912         return security_compute_sid(ssid, tsid, tclass,
1913                                     AVTAB_TRANSITION,
1914                                     qstr ? qstr->name : NULL, out_sid, true);
1915 }
1916
1917 int security_transition_sid_user(u32 ssid, u32 tsid, u16 tclass,
1918                                  const char *objname, u32 *out_sid)
1919 {
1920         return security_compute_sid(ssid, tsid, tclass,
1921                                     AVTAB_TRANSITION,
1922                                     objname, out_sid, false);
1923 }
1924
1925 /**
1926  * security_member_sid - Compute the SID for member selection.
1927  * @ssid: source security identifier
1928  * @tsid: target security identifier
1929  * @tclass: target security class
1930  * @out_sid: security identifier for selected member
1931  *
1932  * Compute a SID to use when selecting a member of a polyinstantiated
1933  * object of class @tclass based on a SID pair (@ssid, @tsid).
1934  * Return -%EINVAL if any of the parameters are invalid, -%ENOMEM
1935  * if insufficient memory is available, or %0 if the SID was
1936  * computed successfully.
1937  */
1938 int security_member_sid(u32 ssid,
1939                         u32 tsid,
1940                         u16 tclass,
1941                         u32 *out_sid)
1942 {
1943         return security_compute_sid(ssid, tsid, tclass,
1944                                     AVTAB_MEMBER, NULL,
1945                                     out_sid, false);
1946 }
1947
1948 /**
1949  * security_change_sid - Compute the SID for object relabeling.
1950  * @ssid: source security identifier
1951  * @tsid: target security identifier
1952  * @tclass: target security class
1953  * @out_sid: security identifier for selected member
1954  *
1955  * Compute a SID to use for relabeling an object of class @tclass
1956  * based on a SID pair (@ssid, @tsid).
1957  * Return -%EINVAL if any of the parameters are invalid, -%ENOMEM
1958  * if insufficient memory is available, or %0 if the SID was
1959  * computed successfully.
1960  */
1961 int security_change_sid(u32 ssid,
1962                         u32 tsid,
1963                         u16 tclass,
1964                         u32 *out_sid)
1965 {
1966         return security_compute_sid(ssid, tsid, tclass, AVTAB_CHANGE, NULL,
1967                                     out_sid, false);
1968 }
1969
1970 static inline int convert_context_handle_invalid_context(
1971         struct policydb *policydb,
1972         struct context *context)
1973 {
1974         char *s;
1975         u32 len;
1976
1977         if (enforcing_enabled())
1978                 return -EINVAL;
1979
1980         if (!context_struct_to_string(policydb, context, &s, &len)) {
1981                 pr_warn("SELinux:  Context %s would be invalid if enforcing\n",
1982                         s);
1983                 kfree(s);
1984         }
1985         return 0;
1986 }
1987
1988 /**
1989  * services_convert_context - Convert a security context across policies.
1990  * @args: populated convert_context_args struct
1991  * @oldc: original context
1992  * @newc: converted context
1993  * @gfp_flags: allocation flags
1994  *
1995  * Convert the values in the security context structure @oldc from the values
1996  * specified in the policy @args->oldp to the values specified in the policy
1997  * @args->newp, storing the new context in @newc, and verifying that the
1998  * context is valid under the new policy.
1999  */
2000 int services_convert_context(struct convert_context_args *args,
2001                              struct context *oldc, struct context *newc,
2002                              gfp_t gfp_flags)
2003 {
2004         struct ocontext *oc;
2005         struct role_datum *role;
2006         struct type_datum *typdatum;
2007         struct user_datum *usrdatum;
2008         char *s;
2009         u32 len;
2010         int rc;
2011
2012         if (oldc->str) {
2013                 s = kstrdup(oldc->str, gfp_flags);
2014                 if (!s)
2015                         return -ENOMEM;
2016
2017                 rc = string_to_context_struct(args->newp, NULL, s, newc, SECSID_NULL);
2018                 if (rc == -EINVAL) {
2019                         /*
2020                          * Retain string representation for later mapping.
2021                          *
2022                          * IMPORTANT: We need to copy the contents of oldc->str
2023                          * back into s again because string_to_context_struct()
2024                          * may have garbled it.
2025                          */
2026                         memcpy(s, oldc->str, oldc->len);
2027                         context_init(newc);
2028                         newc->str = s;
2029                         newc->len = oldc->len;
2030                         return 0;
2031                 }
2032                 kfree(s);
2033                 if (rc) {
2034                         /* Other error condition, e.g. ENOMEM. */
2035                         pr_err("SELinux:   Unable to map context %s, rc = %d.\n",
2036                                oldc->str, -rc);
2037                         return rc;
2038                 }
2039                 pr_info("SELinux:  Context %s became valid (mapped).\n",
2040                         oldc->str);
2041                 return 0;
2042         }
2043
2044         context_init(newc);
2045
2046         /* Convert the user. */
2047         usrdatum = symtab_search(&args->newp->p_users,
2048                                  sym_name(args->oldp, SYM_USERS, oldc->user - 1));
2049         if (!usrdatum)
2050                 goto bad;
2051         newc->user = usrdatum->value;
2052
2053         /* Convert the role. */
2054         role = symtab_search(&args->newp->p_roles,
2055                              sym_name(args->oldp, SYM_ROLES, oldc->role - 1));
2056         if (!role)
2057                 goto bad;
2058         newc->role = role->value;
2059
2060         /* Convert the type. */
2061         typdatum = symtab_search(&args->newp->p_types,
2062                                  sym_name(args->oldp, SYM_TYPES, oldc->type - 1));
2063         if (!typdatum)
2064                 goto bad;
2065         newc->type = typdatum->value;
2066
2067         /* Convert the MLS fields if dealing with MLS policies */
2068         if (args->oldp->mls_enabled && args->newp->mls_enabled) {
2069                 rc = mls_convert_context(args->oldp, args->newp, oldc, newc);
2070                 if (rc)
2071                         goto bad;
2072         } else if (!args->oldp->mls_enabled && args->newp->mls_enabled) {
2073                 /*
2074                  * Switching between non-MLS and MLS policy:
2075                  * ensure that the MLS fields of the context for all
2076                  * existing entries in the sidtab are filled in with a
2077                  * suitable default value, likely taken from one of the
2078                  * initial SIDs.
2079                  */
2080                 oc = args->newp->ocontexts[OCON_ISID];
2081                 while (oc && oc->sid[0] != SECINITSID_UNLABELED)
2082                         oc = oc->next;
2083                 if (!oc) {
2084                         pr_err("SELinux:  unable to look up"
2085                                 " the initial SIDs list\n");
2086                         goto bad;
2087                 }
2088                 rc = mls_range_set(newc, &oc->context[0].range);
2089                 if (rc)
2090                         goto bad;
2091         }
2092
2093         /* Check the validity of the new context. */
2094         if (!policydb_context_isvalid(args->newp, newc)) {
2095                 rc = convert_context_handle_invalid_context(args->oldp, oldc);
2096                 if (rc)
2097                         goto bad;
2098         }
2099
2100         return 0;
2101 bad:
2102         /* Map old representation to string and save it. */
2103         rc = context_struct_to_string(args->oldp, oldc, &s, &len);
2104         if (rc)
2105                 return rc;
2106         context_destroy(newc);
2107         newc->str = s;
2108         newc->len = len;
2109         pr_info("SELinux:  Context %s became invalid (unmapped).\n",
2110                 newc->str);
2111         return 0;
2112 }
2113
2114 static void security_load_policycaps(struct selinux_policy *policy)
2115 {
2116         struct policydb *p;
2117         unsigned int i;
2118         struct ebitmap_node *node;
2119
2120         p = &policy->policydb;
2121
2122         for (i = 0; i < ARRAY_SIZE(selinux_state.policycap); i++)
2123                 WRITE_ONCE(selinux_state.policycap[i],
2124                         ebitmap_get_bit(&p->policycaps, i));
2125
2126         for (i = 0; i < ARRAY_SIZE(selinux_policycap_names); i++)
2127                 pr_info("SELinux:  policy capability %s=%d\n",
2128                         selinux_policycap_names[i],
2129                         ebitmap_get_bit(&p->policycaps, i));
2130
2131         ebitmap_for_each_positive_bit(&p->policycaps, node, i) {
2132                 if (i >= ARRAY_SIZE(selinux_policycap_names))
2133                         pr_info("SELinux:  unknown policy capability %u\n",
2134                                 i);
2135         }
2136 }
2137
2138 static int security_preserve_bools(struct selinux_policy *oldpolicy,
2139                                 struct selinux_policy *newpolicy);
2140
2141 static void selinux_policy_free(struct selinux_policy *policy)
2142 {
2143         if (!policy)
2144                 return;
2145
2146         sidtab_destroy(policy->sidtab);
2147         kfree(policy->map.mapping);
2148         policydb_destroy(&policy->policydb);
2149         kfree(policy->sidtab);
2150         kfree(policy);
2151 }
2152
2153 static void selinux_policy_cond_free(struct selinux_policy *policy)
2154 {
2155         cond_policydb_destroy_dup(&policy->policydb);
2156         kfree(policy);
2157 }
2158
2159 void selinux_policy_cancel(struct selinux_load_state *load_state)
2160 {
2161         struct selinux_state *state = &selinux_state;
2162         struct selinux_policy *oldpolicy;
2163
2164         oldpolicy = rcu_dereference_protected(state->policy,
2165                                         lockdep_is_held(&state->policy_mutex));
2166
2167         sidtab_cancel_convert(oldpolicy->sidtab);
2168         selinux_policy_free(load_state->policy);
2169         kfree(load_state->convert_data);
2170 }
2171
2172 static void selinux_notify_policy_change(u32 seqno)
2173 {
2174         /* Flush external caches and notify userspace of policy load */
2175         avc_ss_reset(seqno);
2176         selnl_notify_policyload(seqno);
2177         selinux_status_update_policyload(seqno);
2178         selinux_netlbl_cache_invalidate();
2179         selinux_xfrm_notify_policyload();
2180         selinux_ima_measure_state_locked();
2181 }
2182
2183 void selinux_policy_commit(struct selinux_load_state *load_state)
2184 {
2185         struct selinux_state *state = &selinux_state;
2186         struct selinux_policy *oldpolicy, *newpolicy = load_state->policy;
2187         unsigned long flags;
2188         u32 seqno;
2189
2190         oldpolicy = rcu_dereference_protected(state->policy,
2191                                         lockdep_is_held(&state->policy_mutex));
2192
2193         /* If switching between different policy types, log MLS status */
2194         if (oldpolicy) {
2195                 if (oldpolicy->policydb.mls_enabled && !newpolicy->policydb.mls_enabled)
2196                         pr_info("SELinux: Disabling MLS support...\n");
2197                 else if (!oldpolicy->policydb.mls_enabled && newpolicy->policydb.mls_enabled)
2198                         pr_info("SELinux: Enabling MLS support...\n");
2199         }
2200
2201         /* Set latest granting seqno for new policy. */
2202         if (oldpolicy)
2203                 newpolicy->latest_granting = oldpolicy->latest_granting + 1;
2204         else
2205                 newpolicy->latest_granting = 1;
2206         seqno = newpolicy->latest_granting;
2207
2208         /* Install the new policy. */
2209         if (oldpolicy) {
2210                 sidtab_freeze_begin(oldpolicy->sidtab, &flags);
2211                 rcu_assign_pointer(state->policy, newpolicy);
2212                 sidtab_freeze_end(oldpolicy->sidtab, &flags);
2213         } else {
2214                 rcu_assign_pointer(state->policy, newpolicy);
2215         }
2216
2217         /* Load the policycaps from the new policy */
2218         security_load_policycaps(newpolicy);
2219
2220         if (!selinux_initialized()) {
2221                 /*
2222                  * After first policy load, the security server is
2223                  * marked as initialized and ready to handle requests and
2224                  * any objects created prior to policy load are then labeled.
2225                  */
2226                 selinux_mark_initialized();
2227                 selinux_complete_init();
2228         }
2229
2230         /* Free the old policy */
2231         synchronize_rcu();
2232         selinux_policy_free(oldpolicy);
2233         kfree(load_state->convert_data);
2234
2235         /* Notify others of the policy change */
2236         selinux_notify_policy_change(seqno);
2237 }
2238
2239 /**
2240  * security_load_policy - Load a security policy configuration.
2241  * @data: binary policy data
2242  * @len: length of data in bytes
2243  * @load_state: policy load state
2244  *
2245  * Load a new set of security policy configuration data,
2246  * validate it and convert the SID table as necessary.
2247  * This function will flush the access vector cache after
2248  * loading the new policy.
2249  */
2250 int security_load_policy(void *data, size_t len,
2251                          struct selinux_load_state *load_state)
2252 {
2253         struct selinux_state *state = &selinux_state;
2254         struct selinux_policy *newpolicy, *oldpolicy;
2255         struct selinux_policy_convert_data *convert_data;
2256         int rc = 0;
2257         struct policy_file file = { data, len }, *fp = &file;
2258
2259         newpolicy = kzalloc(sizeof(*newpolicy), GFP_KERNEL);
2260         if (!newpolicy)
2261                 return -ENOMEM;
2262
2263         newpolicy->sidtab = kzalloc(sizeof(*newpolicy->sidtab), GFP_KERNEL);
2264         if (!newpolicy->sidtab) {
2265                 rc = -ENOMEM;
2266                 goto err_policy;
2267         }
2268
2269         rc = policydb_read(&newpolicy->policydb, fp);
2270         if (rc)
2271                 goto err_sidtab;
2272
2273         newpolicy->policydb.len = len;
2274         rc = selinux_set_mapping(&newpolicy->policydb, secclass_map,
2275                                 &newpolicy->map);
2276         if (rc)
2277                 goto err_policydb;
2278
2279         rc = policydb_load_isids(&newpolicy->policydb, newpolicy->sidtab);
2280         if (rc) {
2281                 pr_err("SELinux:  unable to load the initial SIDs\n");
2282                 goto err_mapping;
2283         }
2284
2285         if (!selinux_initialized()) {
2286                 /* First policy load, so no need to preserve state from old policy */
2287                 load_state->policy = newpolicy;
2288                 load_state->convert_data = NULL;
2289                 return 0;
2290         }
2291
2292         oldpolicy = rcu_dereference_protected(state->policy,
2293                                         lockdep_is_held(&state->policy_mutex));
2294
2295         /* Preserve active boolean values from the old policy */
2296         rc = security_preserve_bools(oldpolicy, newpolicy);
2297         if (rc) {
2298                 pr_err("SELinux:  unable to preserve booleans\n");
2299                 goto err_free_isids;
2300         }
2301
2302         /*
2303          * Convert the internal representations of contexts
2304          * in the new SID table.
2305          */
2306
2307         convert_data = kmalloc(sizeof(*convert_data), GFP_KERNEL);
2308         if (!convert_data) {
2309                 rc = -ENOMEM;
2310                 goto err_free_isids;
2311         }
2312
2313         convert_data->args.oldp = &oldpolicy->policydb;
2314         convert_data->args.newp = &newpolicy->policydb;
2315
2316         convert_data->sidtab_params.args = &convert_data->args;
2317         convert_data->sidtab_params.target = newpolicy->sidtab;
2318
2319         rc = sidtab_convert(oldpolicy->sidtab, &convert_data->sidtab_params);
2320         if (rc) {
2321                 pr_err("SELinux:  unable to convert the internal"
2322                         " representation of contexts in the new SID"
2323                         " table\n");
2324                 goto err_free_convert_data;
2325         }
2326
2327         load_state->policy = newpolicy;
2328         load_state->convert_data = convert_data;
2329         return 0;
2330
2331 err_free_convert_data:
2332         kfree(convert_data);
2333 err_free_isids:
2334         sidtab_destroy(newpolicy->sidtab);
2335 err_mapping:
2336         kfree(newpolicy->map.mapping);
2337 err_policydb:
2338         policydb_destroy(&newpolicy->policydb);
2339 err_sidtab:
2340         kfree(newpolicy->sidtab);
2341 err_policy:
2342         kfree(newpolicy);
2343
2344         return rc;
2345 }
2346
2347 /**
2348  * ocontext_to_sid - Helper to safely get sid for an ocontext
2349  * @sidtab: SID table
2350  * @c: ocontext structure
2351  * @index: index of the context entry (0 or 1)
2352  * @out_sid: pointer to the resulting SID value
2353  *
2354  * For all ocontexts except OCON_ISID the SID fields are populated
2355  * on-demand when needed. Since updating the SID value is an SMP-sensitive
2356  * operation, this helper must be used to do that safely.
2357  *
2358  * WARNING: This function may return -ESTALE, indicating that the caller
2359  * must retry the operation after re-acquiring the policy pointer!
2360  */
2361 static int ocontext_to_sid(struct sidtab *sidtab, struct ocontext *c,
2362                            size_t index, u32 *out_sid)
2363 {
2364         int rc;
2365         u32 sid;
2366
2367         /* Ensure the associated sidtab entry is visible to this thread. */
2368         sid = smp_load_acquire(&c->sid[index]);
2369         if (!sid) {
2370                 rc = sidtab_context_to_sid(sidtab, &c->context[index], &sid);
2371                 if (rc)
2372                         return rc;
2373
2374                 /*
2375                  * Ensure the new sidtab entry is visible to other threads
2376                  * when they see the SID.
2377                  */
2378                 smp_store_release(&c->sid[index], sid);
2379         }
2380         *out_sid = sid;
2381         return 0;
2382 }
2383
2384 /**
2385  * security_port_sid - Obtain the SID for a port.
2386  * @protocol: protocol number
2387  * @port: port number
2388  * @out_sid: security identifier
2389  */
2390 int security_port_sid(u8 protocol, u16 port, u32 *out_sid)
2391 {
2392         struct selinux_policy *policy;
2393         struct policydb *policydb;
2394         struct sidtab *sidtab;
2395         struct ocontext *c;
2396         int rc;
2397
2398         if (!selinux_initialized()) {
2399                 *out_sid = SECINITSID_PORT;
2400                 return 0;
2401         }
2402
2403 retry:
2404         rc = 0;
2405         rcu_read_lock();
2406         policy = rcu_dereference(selinux_state.policy);
2407         policydb = &policy->policydb;
2408         sidtab = policy->sidtab;
2409
2410         c = policydb->ocontexts[OCON_PORT];
2411         while (c) {
2412                 if (c->u.port.protocol == protocol &&
2413                     c->u.port.low_port <= port &&
2414                     c->u.port.high_port >= port)
2415                         break;
2416                 c = c->next;
2417         }
2418
2419         if (c) {
2420                 rc = ocontext_to_sid(sidtab, c, 0, out_sid);
2421                 if (rc == -ESTALE) {
2422                         rcu_read_unlock();
2423                         goto retry;
2424                 }
2425                 if (rc)
2426                         goto out;
2427         } else {
2428                 *out_sid = SECINITSID_PORT;
2429         }
2430
2431 out:
2432         rcu_read_unlock();
2433         return rc;
2434 }
2435
2436 /**
2437  * security_ib_pkey_sid - Obtain the SID for a pkey.
2438  * @subnet_prefix: Subnet Prefix
2439  * @pkey_num: pkey number
2440  * @out_sid: security identifier
2441  */
2442 int security_ib_pkey_sid(u64 subnet_prefix, u16 pkey_num, u32 *out_sid)
2443 {
2444         struct selinux_policy *policy;
2445         struct policydb *policydb;
2446         struct sidtab *sidtab;
2447         struct ocontext *c;
2448         int rc;
2449
2450         if (!selinux_initialized()) {
2451                 *out_sid = SECINITSID_UNLABELED;
2452                 return 0;
2453         }
2454
2455 retry:
2456         rc = 0;
2457         rcu_read_lock();
2458         policy = rcu_dereference(selinux_state.policy);
2459         policydb = &policy->policydb;
2460         sidtab = policy->sidtab;
2461
2462         c = policydb->ocontexts[OCON_IBPKEY];
2463         while (c) {
2464                 if (c->u.ibpkey.low_pkey <= pkey_num &&
2465                     c->u.ibpkey.high_pkey >= pkey_num &&
2466                     c->u.ibpkey.subnet_prefix == subnet_prefix)
2467                         break;
2468
2469                 c = c->next;
2470         }
2471
2472         if (c) {
2473                 rc = ocontext_to_sid(sidtab, c, 0, out_sid);
2474                 if (rc == -ESTALE) {
2475                         rcu_read_unlock();
2476                         goto retry;
2477                 }
2478                 if (rc)
2479                         goto out;
2480         } else
2481                 *out_sid = SECINITSID_UNLABELED;
2482
2483 out:
2484         rcu_read_unlock();
2485         return rc;
2486 }
2487
2488 /**
2489  * security_ib_endport_sid - Obtain the SID for a subnet management interface.
2490  * @dev_name: device name
2491  * @port_num: port number
2492  * @out_sid: security identifier
2493  */
2494 int security_ib_endport_sid(const char *dev_name, u8 port_num, u32 *out_sid)
2495 {
2496         struct selinux_policy *policy;
2497         struct policydb *policydb;
2498         struct sidtab *sidtab;
2499         struct ocontext *c;
2500         int rc;
2501
2502         if (!selinux_initialized()) {
2503                 *out_sid = SECINITSID_UNLABELED;
2504                 return 0;
2505         }
2506
2507 retry:
2508         rc = 0;
2509         rcu_read_lock();
2510         policy = rcu_dereference(selinux_state.policy);
2511         policydb = &policy->policydb;
2512         sidtab = policy->sidtab;
2513
2514         c = policydb->ocontexts[OCON_IBENDPORT];
2515         while (c) {
2516                 if (c->u.ibendport.port == port_num &&
2517                     !strncmp(c->u.ibendport.dev_name,
2518                              dev_name,
2519                              IB_DEVICE_NAME_MAX))
2520                         break;
2521
2522                 c = c->next;
2523         }
2524
2525         if (c) {
2526                 rc = ocontext_to_sid(sidtab, c, 0, out_sid);
2527                 if (rc == -ESTALE) {
2528                         rcu_read_unlock();
2529                         goto retry;
2530                 }
2531                 if (rc)
2532                         goto out;
2533         } else
2534                 *out_sid = SECINITSID_UNLABELED;
2535
2536 out:
2537         rcu_read_unlock();
2538         return rc;
2539 }
2540
2541 /**
2542  * security_netif_sid - Obtain the SID for a network interface.
2543  * @name: interface name
2544  * @if_sid: interface SID
2545  */
2546 int security_netif_sid(char *name, u32 *if_sid)
2547 {
2548         struct selinux_policy *policy;
2549         struct policydb *policydb;
2550         struct sidtab *sidtab;
2551         int rc;
2552         struct ocontext *c;
2553
2554         if (!selinux_initialized()) {
2555                 *if_sid = SECINITSID_NETIF;
2556                 return 0;
2557         }
2558
2559 retry:
2560         rc = 0;
2561         rcu_read_lock();
2562         policy = rcu_dereference(selinux_state.policy);
2563         policydb = &policy->policydb;
2564         sidtab = policy->sidtab;
2565
2566         c = policydb->ocontexts[OCON_NETIF];
2567         while (c) {
2568                 if (strcmp(name, c->u.name) == 0)
2569                         break;
2570                 c = c->next;
2571         }
2572
2573         if (c) {
2574                 rc = ocontext_to_sid(sidtab, c, 0, if_sid);
2575                 if (rc == -ESTALE) {
2576                         rcu_read_unlock();
2577                         goto retry;
2578                 }
2579                 if (rc)
2580                         goto out;
2581         } else
2582                 *if_sid = SECINITSID_NETIF;
2583
2584 out:
2585         rcu_read_unlock();
2586         return rc;
2587 }
2588
2589 static int match_ipv6_addrmask(u32 *input, u32 *addr, u32 *mask)
2590 {
2591         int i, fail = 0;
2592
2593         for (i = 0; i < 4; i++)
2594                 if (addr[i] != (input[i] & mask[i])) {
2595                         fail = 1;
2596                         break;
2597                 }
2598
2599         return !fail;
2600 }
2601
2602 /**
2603  * security_node_sid - Obtain the SID for a node (host).
2604  * @domain: communication domain aka address family
2605  * @addrp: address
2606  * @addrlen: address length in bytes
2607  * @out_sid: security identifier
2608  */
2609 int security_node_sid(u16 domain,
2610                       void *addrp,
2611                       u32 addrlen,
2612                       u32 *out_sid)
2613 {
2614         struct selinux_policy *policy;
2615         struct policydb *policydb;
2616         struct sidtab *sidtab;
2617         int rc;
2618         struct ocontext *c;
2619
2620         if (!selinux_initialized()) {
2621                 *out_sid = SECINITSID_NODE;
2622                 return 0;
2623         }
2624
2625 retry:
2626         rcu_read_lock();
2627         policy = rcu_dereference(selinux_state.policy);
2628         policydb = &policy->policydb;
2629         sidtab = policy->sidtab;
2630
2631         switch (domain) {
2632         case AF_INET: {
2633                 u32 addr;
2634
2635                 rc = -EINVAL;
2636                 if (addrlen != sizeof(u32))
2637                         goto out;
2638
2639                 addr = *((u32 *)addrp);
2640
2641                 c = policydb->ocontexts[OCON_NODE];
2642                 while (c) {
2643                         if (c->u.node.addr == (addr & c->u.node.mask))
2644                                 break;
2645                         c = c->next;
2646                 }
2647                 break;
2648         }
2649
2650         case AF_INET6:
2651                 rc = -EINVAL;
2652                 if (addrlen != sizeof(u64) * 2)
2653                         goto out;
2654                 c = policydb->ocontexts[OCON_NODE6];
2655                 while (c) {
2656                         if (match_ipv6_addrmask(addrp, c->u.node6.addr,
2657                                                 c->u.node6.mask))
2658                                 break;
2659                         c = c->next;
2660                 }
2661                 break;
2662
2663         default:
2664                 rc = 0;
2665                 *out_sid = SECINITSID_NODE;
2666                 goto out;
2667         }
2668
2669         if (c) {
2670                 rc = ocontext_to_sid(sidtab, c, 0, out_sid);
2671                 if (rc == -ESTALE) {
2672                         rcu_read_unlock();
2673                         goto retry;
2674                 }
2675                 if (rc)
2676                         goto out;
2677         } else {
2678                 *out_sid = SECINITSID_NODE;
2679         }
2680
2681         rc = 0;
2682 out:
2683         rcu_read_unlock();
2684         return rc;
2685 }
2686
2687 #define SIDS_NEL 25
2688
2689 /**
2690  * security_get_user_sids - Obtain reachable SIDs for a user.
2691  * @fromsid: starting SID
2692  * @username: username
2693  * @sids: array of reachable SIDs for user
2694  * @nel: number of elements in @sids
2695  *
2696  * Generate the set of SIDs for legal security contexts
2697  * for a given user that can be reached by @fromsid.
2698  * Set *@sids to point to a dynamically allocated
2699  * array containing the set of SIDs.  Set *@nel to the
2700  * number of elements in the array.
2701  */
2702
2703 int security_get_user_sids(u32 fromsid,
2704                            char *username,
2705                            u32 **sids,
2706                            u32 *nel)
2707 {
2708         struct selinux_policy *policy;
2709         struct policydb *policydb;
2710         struct sidtab *sidtab;
2711         struct context *fromcon, usercon;
2712         u32 *mysids = NULL, *mysids2, sid;
2713         u32 i, j, mynel, maxnel = SIDS_NEL;
2714         struct user_datum *user;
2715         struct role_datum *role;
2716         struct ebitmap_node *rnode, *tnode;
2717         int rc;
2718
2719         *sids = NULL;
2720         *nel = 0;
2721
2722         if (!selinux_initialized())
2723                 return 0;
2724
2725         mysids = kcalloc(maxnel, sizeof(*mysids), GFP_KERNEL);
2726         if (!mysids)
2727                 return -ENOMEM;
2728
2729 retry:
2730         mynel = 0;
2731         rcu_read_lock();
2732         policy = rcu_dereference(selinux_state.policy);
2733         policydb = &policy->policydb;
2734         sidtab = policy->sidtab;
2735
2736         context_init(&usercon);
2737
2738         rc = -EINVAL;
2739         fromcon = sidtab_search(sidtab, fromsid);
2740         if (!fromcon)
2741                 goto out_unlock;
2742
2743         rc = -EINVAL;
2744         user = symtab_search(&policydb->p_users, username);
2745         if (!user)
2746                 goto out_unlock;
2747
2748         usercon.user = user->value;
2749
2750         ebitmap_for_each_positive_bit(&user->roles, rnode, i) {
2751                 role = policydb->role_val_to_struct[i];
2752                 usercon.role = i + 1;
2753                 ebitmap_for_each_positive_bit(&role->types, tnode, j) {
2754                         usercon.type = j + 1;
2755
2756                         if (mls_setup_user_range(policydb, fromcon, user,
2757                                                  &usercon))
2758                                 continue;
2759
2760                         rc = sidtab_context_to_sid(sidtab, &usercon, &sid);
2761                         if (rc == -ESTALE) {
2762                                 rcu_read_unlock();
2763                                 goto retry;
2764                         }
2765                         if (rc)
2766                                 goto out_unlock;
2767                         if (mynel < maxnel) {
2768                                 mysids[mynel++] = sid;
2769                         } else {
2770                                 rc = -ENOMEM;
2771                                 maxnel += SIDS_NEL;
2772                                 mysids2 = kcalloc(maxnel, sizeof(*mysids2), GFP_ATOMIC);
2773                                 if (!mysids2)
2774                                         goto out_unlock;
2775                                 memcpy(mysids2, mysids, mynel * sizeof(*mysids2));
2776                                 kfree(mysids);
2777                                 mysids = mysids2;
2778                                 mysids[mynel++] = sid;
2779                         }
2780                 }
2781         }
2782         rc = 0;
2783 out_unlock:
2784         rcu_read_unlock();
2785         if (rc || !mynel) {
2786                 kfree(mysids);
2787                 return rc;
2788         }
2789
2790         rc = -ENOMEM;
2791         mysids2 = kcalloc(mynel, sizeof(*mysids2), GFP_KERNEL);
2792         if (!mysids2) {
2793                 kfree(mysids);
2794                 return rc;
2795         }
2796         for (i = 0, j = 0; i < mynel; i++) {
2797                 struct av_decision dummy_avd;
2798                 rc = avc_has_perm_noaudit(fromsid, mysids[i],
2799                                           SECCLASS_PROCESS, /* kernel value */
2800                                           PROCESS__TRANSITION, AVC_STRICT,
2801                                           &dummy_avd);
2802                 if (!rc)
2803                         mysids2[j++] = mysids[i];
2804                 cond_resched();
2805         }
2806         kfree(mysids);
2807         *sids = mysids2;
2808         *nel = j;
2809         return 0;
2810 }
2811
2812 /**
2813  * __security_genfs_sid - Helper to obtain a SID for a file in a filesystem
2814  * @policy: policy
2815  * @fstype: filesystem type
2816  * @path: path from root of mount
2817  * @orig_sclass: file security class
2818  * @sid: SID for path
2819  *
2820  * Obtain a SID to use for a file in a filesystem that
2821  * cannot support xattr or use a fixed labeling behavior like
2822  * transition SIDs or task SIDs.
2823  *
2824  * WARNING: This function may return -ESTALE, indicating that the caller
2825  * must retry the operation after re-acquiring the policy pointer!
2826  */
2827 static inline int __security_genfs_sid(struct selinux_policy *policy,
2828                                        const char *fstype,
2829                                        const char *path,
2830                                        u16 orig_sclass,
2831                                        u32 *sid)
2832 {
2833         struct policydb *policydb = &policy->policydb;
2834         struct sidtab *sidtab = policy->sidtab;
2835         u16 sclass;
2836         struct genfs *genfs;
2837         struct ocontext *c;
2838         int cmp = 0;
2839
2840         while (path[0] == '/' && path[1] == '/')
2841                 path++;
2842
2843         sclass = unmap_class(&policy->map, orig_sclass);
2844         *sid = SECINITSID_UNLABELED;
2845
2846         for (genfs = policydb->genfs; genfs; genfs = genfs->next) {
2847                 cmp = strcmp(fstype, genfs->fstype);
2848                 if (cmp <= 0)
2849                         break;
2850         }
2851
2852         if (!genfs || cmp)
2853                 return -ENOENT;
2854
2855         for (c = genfs->head; c; c = c->next) {
2856                 size_t len = strlen(c->u.name);
2857                 if ((!c->v.sclass || sclass == c->v.sclass) &&
2858                     (strncmp(c->u.name, path, len) == 0))
2859                         break;
2860         }
2861
2862         if (!c)
2863                 return -ENOENT;
2864
2865         return ocontext_to_sid(sidtab, c, 0, sid);
2866 }
2867
2868 /**
2869  * security_genfs_sid - Obtain a SID for a file in a filesystem
2870  * @fstype: filesystem type
2871  * @path: path from root of mount
2872  * @orig_sclass: file security class
2873  * @sid: SID for path
2874  *
2875  * Acquire policy_rwlock before calling __security_genfs_sid() and release
2876  * it afterward.
2877  */
2878 int security_genfs_sid(const char *fstype,
2879                        const char *path,
2880                        u16 orig_sclass,
2881                        u32 *sid)
2882 {
2883         struct selinux_policy *policy;
2884         int retval;
2885
2886         if (!selinux_initialized()) {
2887                 *sid = SECINITSID_UNLABELED;
2888                 return 0;
2889         }
2890
2891         do {
2892                 rcu_read_lock();
2893                 policy = rcu_dereference(selinux_state.policy);
2894                 retval = __security_genfs_sid(policy, fstype, path,
2895                                               orig_sclass, sid);
2896                 rcu_read_unlock();
2897         } while (retval == -ESTALE);
2898         return retval;
2899 }
2900
2901 int selinux_policy_genfs_sid(struct selinux_policy *policy,
2902                         const char *fstype,
2903                         const char *path,
2904                         u16 orig_sclass,
2905                         u32 *sid)
2906 {
2907         /* no lock required, policy is not yet accessible by other threads */
2908         return __security_genfs_sid(policy, fstype, path, orig_sclass, sid);
2909 }
2910
2911 /**
2912  * security_fs_use - Determine how to handle labeling for a filesystem.
2913  * @sb: superblock in question
2914  */
2915 int security_fs_use(struct super_block *sb)
2916 {
2917         struct selinux_policy *policy;
2918         struct policydb *policydb;
2919         struct sidtab *sidtab;
2920         int rc;
2921         struct ocontext *c;
2922         struct superblock_security_struct *sbsec = selinux_superblock(sb);
2923         const char *fstype = sb->s_type->name;
2924
2925         if (!selinux_initialized()) {
2926                 sbsec->behavior = SECURITY_FS_USE_NONE;
2927                 sbsec->sid = SECINITSID_UNLABELED;
2928                 return 0;
2929         }
2930
2931 retry:
2932         rcu_read_lock();
2933         policy = rcu_dereference(selinux_state.policy);
2934         policydb = &policy->policydb;
2935         sidtab = policy->sidtab;
2936
2937         c = policydb->ocontexts[OCON_FSUSE];
2938         while (c) {
2939                 if (strcmp(fstype, c->u.name) == 0)
2940                         break;
2941                 c = c->next;
2942         }
2943
2944         if (c) {
2945                 sbsec->behavior = c->v.behavior;
2946                 rc = ocontext_to_sid(sidtab, c, 0, &sbsec->sid);
2947                 if (rc == -ESTALE) {
2948                         rcu_read_unlock();
2949                         goto retry;
2950                 }
2951                 if (rc)
2952                         goto out;
2953         } else {
2954                 rc = __security_genfs_sid(policy, fstype, "/",
2955                                         SECCLASS_DIR, &sbsec->sid);
2956                 if (rc == -ESTALE) {
2957                         rcu_read_unlock();
2958                         goto retry;
2959                 }
2960                 if (rc) {
2961                         sbsec->behavior = SECURITY_FS_USE_NONE;
2962                         rc = 0;
2963                 } else {
2964                         sbsec->behavior = SECURITY_FS_USE_GENFS;
2965                 }
2966         }
2967
2968 out:
2969         rcu_read_unlock();
2970         return rc;
2971 }
2972
2973 int security_get_bools(struct selinux_policy *policy,
2974                        u32 *len, char ***names, int **values)
2975 {
2976         struct policydb *policydb;
2977         u32 i;
2978         int rc;
2979
2980         policydb = &policy->policydb;
2981
2982         *names = NULL;
2983         *values = NULL;
2984
2985         rc = 0;
2986         *len = policydb->p_bools.nprim;
2987         if (!*len)
2988                 goto out;
2989
2990         rc = -ENOMEM;
2991         *names = kcalloc(*len, sizeof(char *), GFP_ATOMIC);
2992         if (!*names)
2993                 goto err;
2994
2995         rc = -ENOMEM;
2996         *values = kcalloc(*len, sizeof(int), GFP_ATOMIC);
2997         if (!*values)
2998                 goto err;
2999
3000         for (i = 0; i < *len; i++) {
3001                 (*values)[i] = policydb->bool_val_to_struct[i]->state;
3002
3003                 rc = -ENOMEM;
3004                 (*names)[i] = kstrdup(sym_name(policydb, SYM_BOOLS, i),
3005                                       GFP_ATOMIC);
3006                 if (!(*names)[i])
3007                         goto err;
3008         }
3009         rc = 0;
3010 out:
3011         return rc;
3012 err:
3013         if (*names) {
3014                 for (i = 0; i < *len; i++)
3015                         kfree((*names)[i]);
3016                 kfree(*names);
3017         }
3018         kfree(*values);
3019         *len = 0;
3020         *names = NULL;
3021         *values = NULL;
3022         goto out;
3023 }
3024
3025
3026 int security_set_bools(u32 len, int *values)
3027 {
3028         struct selinux_state *state = &selinux_state;
3029         struct selinux_policy *newpolicy, *oldpolicy;
3030         int rc;
3031         u32 i, seqno = 0;
3032
3033         if (!selinux_initialized())
3034                 return -EINVAL;
3035
3036         oldpolicy = rcu_dereference_protected(state->policy,
3037                                         lockdep_is_held(&state->policy_mutex));
3038
3039         /* Consistency check on number of booleans, should never fail */
3040         if (WARN_ON(len != oldpolicy->policydb.p_bools.nprim))
3041                 return -EINVAL;
3042
3043         newpolicy = kmemdup(oldpolicy, sizeof(*newpolicy), GFP_KERNEL);
3044         if (!newpolicy)
3045                 return -ENOMEM;
3046
3047         /*
3048          * Deep copy only the parts of the policydb that might be
3049          * modified as a result of changing booleans.
3050          */
3051         rc = cond_policydb_dup(&newpolicy->policydb, &oldpolicy->policydb);
3052         if (rc) {
3053                 kfree(newpolicy);
3054                 return -ENOMEM;
3055         }
3056
3057         /* Update the boolean states in the copy */
3058         for (i = 0; i < len; i++) {
3059                 int new_state = !!values[i];
3060                 int old_state = newpolicy->policydb.bool_val_to_struct[i]->state;
3061
3062                 if (new_state != old_state) {
3063                         audit_log(audit_context(), GFP_ATOMIC,
3064                                 AUDIT_MAC_CONFIG_CHANGE,
3065                                 "bool=%s val=%d old_val=%d auid=%u ses=%u",
3066                                 sym_name(&newpolicy->policydb, SYM_BOOLS, i),
3067                                 new_state,
3068                                 old_state,
3069                                 from_kuid(&init_user_ns, audit_get_loginuid(current)),
3070                                 audit_get_sessionid(current));
3071                         newpolicy->policydb.bool_val_to_struct[i]->state = new_state;
3072                 }
3073         }
3074
3075         /* Re-evaluate the conditional rules in the copy */
3076         evaluate_cond_nodes(&newpolicy->policydb);
3077
3078         /* Set latest granting seqno for new policy */
3079         newpolicy->latest_granting = oldpolicy->latest_granting + 1;
3080         seqno = newpolicy->latest_granting;
3081
3082         /* Install the new policy */
3083         rcu_assign_pointer(state->policy, newpolicy);
3084
3085         /*
3086          * Free the conditional portions of the old policydb
3087          * that were copied for the new policy, and the oldpolicy
3088          * structure itself but not what it references.
3089          */
3090         synchronize_rcu();
3091         selinux_policy_cond_free(oldpolicy);
3092
3093         /* Notify others of the policy change */
3094         selinux_notify_policy_change(seqno);
3095         return 0;
3096 }
3097
3098 int security_get_bool_value(u32 index)
3099 {
3100         struct selinux_policy *policy;
3101         struct policydb *policydb;
3102         int rc;
3103         u32 len;
3104
3105         if (!selinux_initialized())
3106                 return 0;
3107
3108         rcu_read_lock();
3109         policy = rcu_dereference(selinux_state.policy);
3110         policydb = &policy->policydb;
3111
3112         rc = -EFAULT;
3113         len = policydb->p_bools.nprim;
3114         if (index >= len)
3115                 goto out;
3116
3117         rc = policydb->bool_val_to_struct[index]->state;
3118 out:
3119         rcu_read_unlock();
3120         return rc;
3121 }
3122
3123 static int security_preserve_bools(struct selinux_policy *oldpolicy,
3124                                 struct selinux_policy *newpolicy)
3125 {
3126         int rc, *bvalues = NULL;
3127         char **bnames = NULL;
3128         struct cond_bool_datum *booldatum;
3129         u32 i, nbools = 0;
3130
3131         rc = security_get_bools(oldpolicy, &nbools, &bnames, &bvalues);
3132         if (rc)
3133                 goto out;
3134         for (i = 0; i < nbools; i++) {
3135                 booldatum = symtab_search(&newpolicy->policydb.p_bools,
3136                                         bnames[i]);
3137                 if (booldatum)
3138                         booldatum->state = bvalues[i];
3139         }
3140         evaluate_cond_nodes(&newpolicy->policydb);
3141
3142 out:
3143         if (bnames) {
3144                 for (i = 0; i < nbools; i++)
3145                         kfree(bnames[i]);
3146         }
3147         kfree(bnames);
3148         kfree(bvalues);
3149         return rc;
3150 }
3151
3152 /*
3153  * security_sid_mls_copy() - computes a new sid based on the given
3154  * sid and the mls portion of mls_sid.
3155  */
3156 int security_sid_mls_copy(u32 sid, u32 mls_sid, u32 *new_sid)
3157 {
3158         struct selinux_policy *policy;
3159         struct policydb *policydb;
3160         struct sidtab *sidtab;
3161         struct context *context1;
3162         struct context *context2;
3163         struct context newcon;
3164         char *s;
3165         u32 len;
3166         int rc;
3167
3168         if (!selinux_initialized()) {
3169                 *new_sid = sid;
3170                 return 0;
3171         }
3172
3173 retry:
3174         rc = 0;
3175         context_init(&newcon);
3176
3177         rcu_read_lock();
3178         policy = rcu_dereference(selinux_state.policy);
3179         policydb = &policy->policydb;
3180         sidtab = policy->sidtab;
3181
3182         if (!policydb->mls_enabled) {
3183                 *new_sid = sid;
3184                 goto out_unlock;
3185         }
3186
3187         rc = -EINVAL;
3188         context1 = sidtab_search(sidtab, sid);
3189         if (!context1) {
3190                 pr_err("SELinux: %s:  unrecognized SID %d\n",
3191                         __func__, sid);
3192                 goto out_unlock;
3193         }
3194
3195         rc = -EINVAL;
3196         context2 = sidtab_search(sidtab, mls_sid);
3197         if (!context2) {
3198                 pr_err("SELinux: %s:  unrecognized SID %d\n",
3199                         __func__, mls_sid);
3200                 goto out_unlock;
3201         }
3202
3203         newcon.user = context1->user;
3204         newcon.role = context1->role;
3205         newcon.type = context1->type;
3206         rc = mls_context_cpy(&newcon, context2);
3207         if (rc)
3208                 goto out_unlock;
3209
3210         /* Check the validity of the new context. */
3211         if (!policydb_context_isvalid(policydb, &newcon)) {
3212                 rc = convert_context_handle_invalid_context(policydb,
3213                                                         &newcon);
3214                 if (rc) {
3215                         if (!context_struct_to_string(policydb, &newcon, &s,
3216                                                       &len)) {
3217                                 struct audit_buffer *ab;
3218
3219                                 ab = audit_log_start(audit_context(),
3220                                                      GFP_ATOMIC,
3221                                                      AUDIT_SELINUX_ERR);
3222                                 audit_log_format(ab,
3223                                                  "op=security_sid_mls_copy invalid_context=");
3224                                 /* don't record NUL with untrusted strings */
3225                                 audit_log_n_untrustedstring(ab, s, len - 1);
3226                                 audit_log_end(ab);
3227                                 kfree(s);
3228                         }
3229                         goto out_unlock;
3230                 }
3231         }
3232         rc = sidtab_context_to_sid(sidtab, &newcon, new_sid);
3233         if (rc == -ESTALE) {
3234                 rcu_read_unlock();
3235                 context_destroy(&newcon);
3236                 goto retry;
3237         }
3238 out_unlock:
3239         rcu_read_unlock();
3240         context_destroy(&newcon);
3241         return rc;
3242 }
3243
3244 /**
3245  * security_net_peersid_resolve - Compare and resolve two network peer SIDs
3246  * @nlbl_sid: NetLabel SID
3247  * @nlbl_type: NetLabel labeling protocol type
3248  * @xfrm_sid: XFRM SID
3249  * @peer_sid: network peer sid
3250  *
3251  * Description:
3252  * Compare the @nlbl_sid and @xfrm_sid values and if the two SIDs can be
3253  * resolved into a single SID it is returned via @peer_sid and the function
3254  * returns zero.  Otherwise @peer_sid is set to SECSID_NULL and the function
3255  * returns a negative value.  A table summarizing the behavior is below:
3256  *
3257  *                                 | function return |      @sid
3258  *   ------------------------------+-----------------+-----------------
3259  *   no peer labels                |        0        |    SECSID_NULL
3260  *   single peer label             |        0        |    <peer_label>
3261  *   multiple, consistent labels   |        0        |    <peer_label>
3262  *   multiple, inconsistent labels |    -<errno>     |    SECSID_NULL
3263  *
3264  */
3265 int security_net_peersid_resolve(u32 nlbl_sid, u32 nlbl_type,
3266                                  u32 xfrm_sid,
3267                                  u32 *peer_sid)
3268 {
3269         struct selinux_policy *policy;
3270         struct policydb *policydb;
3271         struct sidtab *sidtab;
3272         int rc;
3273         struct context *nlbl_ctx;
3274         struct context *xfrm_ctx;
3275
3276         *peer_sid = SECSID_NULL;
3277
3278         /* handle the common (which also happens to be the set of easy) cases
3279          * right away, these two if statements catch everything involving a
3280          * single or absent peer SID/label */
3281         if (xfrm_sid == SECSID_NULL) {
3282                 *peer_sid = nlbl_sid;
3283                 return 0;
3284         }
3285         /* NOTE: an nlbl_type == NETLBL_NLTYPE_UNLABELED is a "fallback" label
3286          * and is treated as if nlbl_sid == SECSID_NULL when a XFRM SID/label
3287          * is present */
3288         if (nlbl_sid == SECSID_NULL || nlbl_type == NETLBL_NLTYPE_UNLABELED) {
3289                 *peer_sid = xfrm_sid;
3290                 return 0;
3291         }
3292
3293         if (!selinux_initialized())
3294                 return 0;
3295
3296         rcu_read_lock();
3297         policy = rcu_dereference(selinux_state.policy);
3298         policydb = &policy->policydb;
3299         sidtab = policy->sidtab;
3300
3301         /*
3302          * We don't need to check initialized here since the only way both
3303          * nlbl_sid and xfrm_sid are not equal to SECSID_NULL would be if the
3304          * security server was initialized and state->initialized was true.
3305          */
3306         if (!policydb->mls_enabled) {
3307                 rc = 0;
3308                 goto out;
3309         }
3310
3311         rc = -EINVAL;
3312         nlbl_ctx = sidtab_search(sidtab, nlbl_sid);
3313         if (!nlbl_ctx) {
3314                 pr_err("SELinux: %s:  unrecognized SID %d\n",
3315                        __func__, nlbl_sid);
3316                 goto out;
3317         }
3318         rc = -EINVAL;
3319         xfrm_ctx = sidtab_search(sidtab, xfrm_sid);
3320         if (!xfrm_ctx) {
3321                 pr_err("SELinux: %s:  unrecognized SID %d\n",
3322                        __func__, xfrm_sid);
3323                 goto out;
3324         }
3325         rc = (mls_context_cmp(nlbl_ctx, xfrm_ctx) ? 0 : -EACCES);
3326         if (rc)
3327                 goto out;
3328
3329         /* at present NetLabel SIDs/labels really only carry MLS
3330          * information so if the MLS portion of the NetLabel SID
3331          * matches the MLS portion of the labeled XFRM SID/label
3332          * then pass along the XFRM SID as it is the most
3333          * expressive */
3334         *peer_sid = xfrm_sid;
3335 out:
3336         rcu_read_unlock();
3337         return rc;
3338 }
3339
3340 static int get_classes_callback(void *k, void *d, void *args)
3341 {
3342         struct class_datum *datum = d;
3343         char *name = k, **classes = args;
3344         u32 value = datum->value - 1;
3345
3346         classes[value] = kstrdup(name, GFP_ATOMIC);
3347         if (!classes[value])
3348                 return -ENOMEM;
3349
3350         return 0;
3351 }
3352
3353 int security_get_classes(struct selinux_policy *policy,
3354                          char ***classes, u32 *nclasses)
3355 {
3356         struct policydb *policydb;
3357         int rc;
3358
3359         policydb = &policy->policydb;
3360
3361         rc = -ENOMEM;
3362         *nclasses = policydb->p_classes.nprim;
3363         *classes = kcalloc(*nclasses, sizeof(**classes), GFP_ATOMIC);
3364         if (!*classes)
3365                 goto out;
3366
3367         rc = hashtab_map(&policydb->p_classes.table, get_classes_callback,
3368                          *classes);
3369         if (rc) {
3370                 u32 i;
3371
3372                 for (i = 0; i < *nclasses; i++)
3373                         kfree((*classes)[i]);
3374                 kfree(*classes);
3375         }
3376
3377 out:
3378         return rc;
3379 }
3380
3381 static int get_permissions_callback(void *k, void *d, void *args)
3382 {
3383         struct perm_datum *datum = d;
3384         char *name = k, **perms = args;
3385         u32 value = datum->value - 1;
3386
3387         perms[value] = kstrdup(name, GFP_ATOMIC);
3388         if (!perms[value])
3389                 return -ENOMEM;
3390
3391         return 0;
3392 }
3393
3394 int security_get_permissions(struct selinux_policy *policy,
3395                              const char *class, char ***perms, u32 *nperms)
3396 {
3397         struct policydb *policydb;
3398         u32 i;
3399         int rc;
3400         struct class_datum *match;
3401
3402         policydb = &policy->policydb;
3403
3404         rc = -EINVAL;
3405         match = symtab_search(&policydb->p_classes, class);
3406         if (!match) {
3407                 pr_err("SELinux: %s:  unrecognized class %s\n",
3408                         __func__, class);
3409                 goto out;
3410         }
3411
3412         rc = -ENOMEM;
3413         *nperms = match->permissions.nprim;
3414         *perms = kcalloc(*nperms, sizeof(**perms), GFP_ATOMIC);
3415         if (!*perms)
3416                 goto out;
3417
3418         if (match->comdatum) {
3419                 rc = hashtab_map(&match->comdatum->permissions.table,
3420                                  get_permissions_callback, *perms);
3421                 if (rc)
3422                         goto err;
3423         }
3424
3425         rc = hashtab_map(&match->permissions.table, get_permissions_callback,
3426                          *perms);
3427         if (rc)
3428                 goto err;
3429
3430 out:
3431         return rc;
3432
3433 err:
3434         for (i = 0; i < *nperms; i++)
3435                 kfree((*perms)[i]);
3436         kfree(*perms);
3437         return rc;
3438 }
3439
3440 int security_get_reject_unknown(void)
3441 {
3442         struct selinux_policy *policy;
3443         int value;
3444
3445         if (!selinux_initialized())
3446                 return 0;
3447
3448         rcu_read_lock();
3449         policy = rcu_dereference(selinux_state.policy);
3450         value = policy->policydb.reject_unknown;
3451         rcu_read_unlock();
3452         return value;
3453 }
3454
3455 int security_get_allow_unknown(void)
3456 {
3457         struct selinux_policy *policy;
3458         int value;
3459
3460         if (!selinux_initialized())
3461                 return 0;
3462
3463         rcu_read_lock();
3464         policy = rcu_dereference(selinux_state.policy);
3465         value = policy->policydb.allow_unknown;
3466         rcu_read_unlock();
3467         return value;
3468 }
3469
3470 /**
3471  * security_policycap_supported - Check for a specific policy capability
3472  * @req_cap: capability
3473  *
3474  * Description:
3475  * This function queries the currently loaded policy to see if it supports the
3476  * capability specified by @req_cap.  Returns true (1) if the capability is
3477  * supported, false (0) if it isn't supported.
3478  *
3479  */
3480 int security_policycap_supported(unsigned int req_cap)
3481 {
3482         struct selinux_policy *policy;
3483         int rc;
3484
3485         if (!selinux_initialized())
3486                 return 0;
3487
3488         rcu_read_lock();
3489         policy = rcu_dereference(selinux_state.policy);
3490         rc = ebitmap_get_bit(&policy->policydb.policycaps, req_cap);
3491         rcu_read_unlock();
3492
3493         return rc;
3494 }
3495
3496 struct selinux_audit_rule {
3497         u32 au_seqno;
3498         struct context au_ctxt;
3499 };
3500
3501 void selinux_audit_rule_free(void *vrule)
3502 {
3503         struct selinux_audit_rule *rule = vrule;
3504
3505         if (rule) {
3506                 context_destroy(&rule->au_ctxt);
3507                 kfree(rule);
3508         }
3509 }
3510
3511 int selinux_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
3512 {
3513         struct selinux_state *state = &selinux_state;
3514         struct selinux_policy *policy;
3515         struct policydb *policydb;
3516         struct selinux_audit_rule *tmprule;
3517         struct role_datum *roledatum;
3518         struct type_datum *typedatum;
3519         struct user_datum *userdatum;
3520         struct selinux_audit_rule **rule = (struct selinux_audit_rule **)vrule;
3521         int rc = 0;
3522
3523         *rule = NULL;
3524
3525         if (!selinux_initialized())
3526                 return -EOPNOTSUPP;
3527
3528         switch (field) {
3529         case AUDIT_SUBJ_USER:
3530         case AUDIT_SUBJ_ROLE:
3531         case AUDIT_SUBJ_TYPE:
3532         case AUDIT_OBJ_USER:
3533         case AUDIT_OBJ_ROLE:
3534         case AUDIT_OBJ_TYPE:
3535                 /* only 'equals' and 'not equals' fit user, role, and type */
3536                 if (op != Audit_equal && op != Audit_not_equal)
3537                         return -EINVAL;
3538                 break;
3539         case AUDIT_SUBJ_SEN:
3540         case AUDIT_SUBJ_CLR:
3541         case AUDIT_OBJ_LEV_LOW:
3542         case AUDIT_OBJ_LEV_HIGH:
3543                 /* we do not allow a range, indicated by the presence of '-' */
3544                 if (strchr(rulestr, '-'))
3545                         return -EINVAL;
3546                 break;
3547         default:
3548                 /* only the above fields are valid */
3549                 return -EINVAL;
3550         }
3551
3552         tmprule = kzalloc(sizeof(struct selinux_audit_rule), GFP_KERNEL);
3553         if (!tmprule)
3554                 return -ENOMEM;
3555         context_init(&tmprule->au_ctxt);
3556
3557         rcu_read_lock();
3558         policy = rcu_dereference(state->policy);
3559         policydb = &policy->policydb;
3560         tmprule->au_seqno = policy->latest_granting;
3561         switch (field) {
3562         case AUDIT_SUBJ_USER:
3563         case AUDIT_OBJ_USER:
3564                 userdatum = symtab_search(&policydb->p_users, rulestr);
3565                 if (!userdatum) {
3566                         rc = -EINVAL;
3567                         goto err;
3568                 }
3569                 tmprule->au_ctxt.user = userdatum->value;
3570                 break;
3571         case AUDIT_SUBJ_ROLE:
3572         case AUDIT_OBJ_ROLE:
3573                 roledatum = symtab_search(&policydb->p_roles, rulestr);
3574                 if (!roledatum) {
3575                         rc = -EINVAL;
3576                         goto err;
3577                 }
3578                 tmprule->au_ctxt.role = roledatum->value;
3579                 break;
3580         case AUDIT_SUBJ_TYPE:
3581         case AUDIT_OBJ_TYPE:
3582                 typedatum = symtab_search(&policydb->p_types, rulestr);
3583                 if (!typedatum) {
3584                         rc = -EINVAL;
3585                         goto err;
3586                 }
3587                 tmprule->au_ctxt.type = typedatum->value;
3588                 break;
3589         case AUDIT_SUBJ_SEN:
3590         case AUDIT_SUBJ_CLR:
3591         case AUDIT_OBJ_LEV_LOW:
3592         case AUDIT_OBJ_LEV_HIGH:
3593                 rc = mls_from_string(policydb, rulestr, &tmprule->au_ctxt,
3594                                      GFP_ATOMIC);
3595                 if (rc)
3596                         goto err;
3597                 break;
3598         }
3599         rcu_read_unlock();
3600
3601         *rule = tmprule;
3602         return 0;
3603
3604 err:
3605         rcu_read_unlock();
3606         selinux_audit_rule_free(tmprule);
3607         *rule = NULL;
3608         return rc;
3609 }
3610
3611 /* Check to see if the rule contains any selinux fields */
3612 int selinux_audit_rule_known(struct audit_krule *rule)
3613 {
3614         u32 i;
3615
3616         for (i = 0; i < rule->field_count; i++) {
3617                 struct audit_field *f = &rule->fields[i];
3618                 switch (f->type) {
3619                 case AUDIT_SUBJ_USER:
3620                 case AUDIT_SUBJ_ROLE:
3621                 case AUDIT_SUBJ_TYPE:
3622                 case AUDIT_SUBJ_SEN:
3623                 case AUDIT_SUBJ_CLR:
3624                 case AUDIT_OBJ_USER:
3625                 case AUDIT_OBJ_ROLE:
3626                 case AUDIT_OBJ_TYPE:
3627                 case AUDIT_OBJ_LEV_LOW:
3628                 case AUDIT_OBJ_LEV_HIGH:
3629                         return 1;
3630                 }
3631         }
3632
3633         return 0;
3634 }
3635
3636 int selinux_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule)
3637 {
3638         struct selinux_state *state = &selinux_state;
3639         struct selinux_policy *policy;
3640         struct context *ctxt;
3641         struct mls_level *level;
3642         struct selinux_audit_rule *rule = vrule;
3643         int match = 0;
3644
3645         if (unlikely(!rule)) {
3646                 WARN_ONCE(1, "selinux_audit_rule_match: missing rule\n");
3647                 return -ENOENT;
3648         }
3649
3650         if (!selinux_initialized())
3651                 return 0;
3652
3653         rcu_read_lock();
3654
3655         policy = rcu_dereference(state->policy);
3656
3657         if (rule->au_seqno < policy->latest_granting) {
3658                 match = -ESTALE;
3659                 goto out;
3660         }
3661
3662         ctxt = sidtab_search(policy->sidtab, sid);
3663         if (unlikely(!ctxt)) {
3664                 WARN_ONCE(1, "selinux_audit_rule_match: unrecognized SID %d\n",
3665                           sid);
3666                 match = -ENOENT;
3667                 goto out;
3668         }
3669
3670         /* a field/op pair that is not caught here will simply fall through
3671            without a match */
3672         switch (field) {
3673         case AUDIT_SUBJ_USER:
3674         case AUDIT_OBJ_USER:
3675                 switch (op) {
3676                 case Audit_equal:
3677                         match = (ctxt->user == rule->au_ctxt.user);
3678                         break;
3679                 case Audit_not_equal:
3680                         match = (ctxt->user != rule->au_ctxt.user);
3681                         break;
3682                 }
3683                 break;
3684         case AUDIT_SUBJ_ROLE:
3685         case AUDIT_OBJ_ROLE:
3686                 switch (op) {
3687                 case Audit_equal:
3688                         match = (ctxt->role == rule->au_ctxt.role);
3689                         break;
3690                 case Audit_not_equal:
3691                         match = (ctxt->role != rule->au_ctxt.role);
3692                         break;
3693                 }
3694                 break;
3695         case AUDIT_SUBJ_TYPE:
3696         case AUDIT_OBJ_TYPE:
3697                 switch (op) {
3698                 case Audit_equal:
3699                         match = (ctxt->type == rule->au_ctxt.type);
3700                         break;
3701                 case Audit_not_equal:
3702                         match = (ctxt->type != rule->au_ctxt.type);
3703                         break;
3704                 }
3705                 break;
3706         case AUDIT_SUBJ_SEN:
3707         case AUDIT_SUBJ_CLR:
3708         case AUDIT_OBJ_LEV_LOW:
3709         case AUDIT_OBJ_LEV_HIGH:
3710                 level = ((field == AUDIT_SUBJ_SEN ||
3711                           field == AUDIT_OBJ_LEV_LOW) ?
3712                          &ctxt->range.level[0] : &ctxt->range.level[1]);
3713                 switch (op) {
3714                 case Audit_equal:
3715                         match = mls_level_eq(&rule->au_ctxt.range.level[0],
3716                                              level);
3717                         break;
3718                 case Audit_not_equal:
3719                         match = !mls_level_eq(&rule->au_ctxt.range.level[0],
3720                                               level);
3721                         break;
3722                 case Audit_lt:
3723                         match = (mls_level_dom(&rule->au_ctxt.range.level[0],
3724                                                level) &&
3725                                  !mls_level_eq(&rule->au_ctxt.range.level[0],
3726                                                level));
3727                         break;
3728                 case Audit_le:
3729                         match = mls_level_dom(&rule->au_ctxt.range.level[0],
3730                                               level);
3731                         break;
3732                 case Audit_gt:
3733                         match = (mls_level_dom(level,
3734                                               &rule->au_ctxt.range.level[0]) &&
3735                                  !mls_level_eq(level,
3736                                                &rule->au_ctxt.range.level[0]));
3737                         break;
3738                 case Audit_ge:
3739                         match = mls_level_dom(level,
3740                                               &rule->au_ctxt.range.level[0]);
3741                         break;
3742                 }
3743         }
3744
3745 out:
3746         rcu_read_unlock();
3747         return match;
3748 }
3749
3750 static int aurule_avc_callback(u32 event)
3751 {
3752         if (event == AVC_CALLBACK_RESET)
3753                 return audit_update_lsm_rules();
3754         return 0;
3755 }
3756
3757 static int __init aurule_init(void)
3758 {
3759         int err;
3760
3761         err = avc_add_callback(aurule_avc_callback, AVC_CALLBACK_RESET);
3762         if (err)
3763                 panic("avc_add_callback() failed, error %d\n", err);
3764
3765         return err;
3766 }
3767 __initcall(aurule_init);
3768
3769 #ifdef CONFIG_NETLABEL
3770 /**
3771  * security_netlbl_cache_add - Add an entry to the NetLabel cache
3772  * @secattr: the NetLabel packet security attributes
3773  * @sid: the SELinux SID
3774  *
3775  * Description:
3776  * Attempt to cache the context in @ctx, which was derived from the packet in
3777  * @skb, in the NetLabel subsystem cache.  This function assumes @secattr has
3778  * already been initialized.
3779  *
3780  */
3781 static void security_netlbl_cache_add(struct netlbl_lsm_secattr *secattr,
3782                                       u32 sid)
3783 {
3784         u32 *sid_cache;
3785
3786         sid_cache = kmalloc(sizeof(*sid_cache), GFP_ATOMIC);
3787         if (sid_cache == NULL)
3788                 return;
3789         secattr->cache = netlbl_secattr_cache_alloc(GFP_ATOMIC);
3790         if (secattr->cache == NULL) {
3791                 kfree(sid_cache);
3792                 return;
3793         }
3794
3795         *sid_cache = sid;
3796         secattr->cache->free = kfree;
3797         secattr->cache->data = sid_cache;
3798         secattr->flags |= NETLBL_SECATTR_CACHE;
3799 }
3800
3801 /**
3802  * security_netlbl_secattr_to_sid - Convert a NetLabel secattr to a SELinux SID
3803  * @secattr: the NetLabel packet security attributes
3804  * @sid: the SELinux SID
3805  *
3806  * Description:
3807  * Convert the given NetLabel security attributes in @secattr into a
3808  * SELinux SID.  If the @secattr field does not contain a full SELinux
3809  * SID/context then use SECINITSID_NETMSG as the foundation.  If possible the
3810  * 'cache' field of @secattr is set and the CACHE flag is set; this is to
3811  * allow the @secattr to be used by NetLabel to cache the secattr to SID
3812  * conversion for future lookups.  Returns zero on success, negative values on
3813  * failure.
3814  *
3815  */
3816 int security_netlbl_secattr_to_sid(struct netlbl_lsm_secattr *secattr,
3817                                    u32 *sid)
3818 {
3819         struct selinux_policy *policy;
3820         struct policydb *policydb;
3821         struct sidtab *sidtab;
3822         int rc;
3823         struct context *ctx;
3824         struct context ctx_new;
3825
3826         if (!selinux_initialized()) {
3827                 *sid = SECSID_NULL;
3828                 return 0;
3829         }
3830
3831 retry:
3832         rc = 0;
3833         rcu_read_lock();
3834         policy = rcu_dereference(selinux_state.policy);
3835         policydb = &policy->policydb;
3836         sidtab = policy->sidtab;
3837
3838         if (secattr->flags & NETLBL_SECATTR_CACHE)
3839                 *sid = *(u32 *)secattr->cache->data;
3840         else if (secattr->flags & NETLBL_SECATTR_SECID)
3841                 *sid = secattr->attr.secid;
3842         else if (secattr->flags & NETLBL_SECATTR_MLS_LVL) {
3843                 rc = -EIDRM;
3844                 ctx = sidtab_search(sidtab, SECINITSID_NETMSG);
3845                 if (ctx == NULL)
3846                         goto out;
3847
3848                 context_init(&ctx_new);
3849                 ctx_new.user = ctx->user;
3850                 ctx_new.role = ctx->role;
3851                 ctx_new.type = ctx->type;
3852                 mls_import_netlbl_lvl(policydb, &ctx_new, secattr);
3853                 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
3854                         rc = mls_import_netlbl_cat(policydb, &ctx_new, secattr);
3855                         if (rc)
3856                                 goto out;
3857                 }
3858                 rc = -EIDRM;
3859                 if (!mls_context_isvalid(policydb, &ctx_new)) {
3860                         ebitmap_destroy(&ctx_new.range.level[0].cat);
3861                         goto out;
3862                 }
3863
3864                 rc = sidtab_context_to_sid(sidtab, &ctx_new, sid);
3865                 ebitmap_destroy(&ctx_new.range.level[0].cat);
3866                 if (rc == -ESTALE) {
3867                         rcu_read_unlock();
3868                         goto retry;
3869                 }
3870                 if (rc)
3871                         goto out;
3872
3873                 security_netlbl_cache_add(secattr, *sid);
3874         } else
3875                 *sid = SECSID_NULL;
3876
3877 out:
3878         rcu_read_unlock();
3879         return rc;
3880 }
3881
3882 /**
3883  * security_netlbl_sid_to_secattr - Convert a SELinux SID to a NetLabel secattr
3884  * @sid: the SELinux SID
3885  * @secattr: the NetLabel packet security attributes
3886  *
3887  * Description:
3888  * Convert the given SELinux SID in @sid into a NetLabel security attribute.
3889  * Returns zero on success, negative values on failure.
3890  *
3891  */
3892 int security_netlbl_sid_to_secattr(u32 sid, struct netlbl_lsm_secattr *secattr)
3893 {
3894         struct selinux_policy *policy;
3895         struct policydb *policydb;
3896         int rc;
3897         struct context *ctx;
3898
3899         if (!selinux_initialized())
3900                 return 0;
3901
3902         rcu_read_lock();
3903         policy = rcu_dereference(selinux_state.policy);
3904         policydb = &policy->policydb;
3905
3906         rc = -ENOENT;
3907         ctx = sidtab_search(policy->sidtab, sid);
3908         if (ctx == NULL)
3909                 goto out;
3910
3911         rc = -ENOMEM;
3912         secattr->domain = kstrdup(sym_name(policydb, SYM_TYPES, ctx->type - 1),
3913                                   GFP_ATOMIC);
3914         if (secattr->domain == NULL)
3915                 goto out;
3916
3917         secattr->attr.secid = sid;
3918         secattr->flags |= NETLBL_SECATTR_DOMAIN_CPY | NETLBL_SECATTR_SECID;
3919         mls_export_netlbl_lvl(policydb, ctx, secattr);
3920         rc = mls_export_netlbl_cat(policydb, ctx, secattr);
3921 out:
3922         rcu_read_unlock();
3923         return rc;
3924 }
3925 #endif /* CONFIG_NETLABEL */
3926
3927 /**
3928  * __security_read_policy - read the policy.
3929  * @policy: SELinux policy
3930  * @data: binary policy data
3931  * @len: length of data in bytes
3932  *
3933  */
3934 static int __security_read_policy(struct selinux_policy *policy,
3935                                   void *data, size_t *len)
3936 {
3937         int rc;
3938         struct policy_file fp;
3939
3940         fp.data = data;
3941         fp.len = *len;
3942
3943         rc = policydb_write(&policy->policydb, &fp);
3944         if (rc)
3945                 return rc;
3946
3947         *len = (unsigned long)fp.data - (unsigned long)data;
3948         return 0;
3949 }
3950
3951 /**
3952  * security_read_policy - read the policy.
3953  * @data: binary policy data
3954  * @len: length of data in bytes
3955  *
3956  */
3957 int security_read_policy(void **data, size_t *len)
3958 {
3959         struct selinux_state *state = &selinux_state;
3960         struct selinux_policy *policy;
3961
3962         policy = rcu_dereference_protected(
3963                         state->policy, lockdep_is_held(&state->policy_mutex));
3964         if (!policy)
3965                 return -EINVAL;
3966
3967         *len = policy->policydb.len;
3968         *data = vmalloc_user(*len);
3969         if (!*data)
3970                 return -ENOMEM;
3971
3972         return __security_read_policy(policy, *data, len);
3973 }
3974
3975 /**
3976  * security_read_state_kernel - read the policy.
3977  * @data: binary policy data
3978  * @len: length of data in bytes
3979  *
3980  * Allocates kernel memory for reading SELinux policy.
3981  * This function is for internal use only and should not
3982  * be used for returning data to user space.
3983  *
3984  * This function must be called with policy_mutex held.
3985  */
3986 int security_read_state_kernel(void **data, size_t *len)
3987 {
3988         int err;
3989         struct selinux_state *state = &selinux_state;
3990         struct selinux_policy *policy;
3991
3992         policy = rcu_dereference_protected(
3993                         state->policy, lockdep_is_held(&state->policy_mutex));
3994         if (!policy)
3995                 return -EINVAL;
3996
3997         *len = policy->policydb.len;
3998         *data = vmalloc(*len);
3999         if (!*data)
4000                 return -ENOMEM;
4001
4002         err = __security_read_policy(policy, *data, len);
4003         if (err) {
4004                 vfree(*data);
4005                 *data = NULL;
4006                 *len = 0;
4007         }
4008         return err;
4009 }