security/apparmor/domain.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * AppArmor security module
   4  *
   5  * This file contains AppArmor policy attachment and domain transitions
   6  *
   7  * Copyright (C) 2002-2008 Novell/SUSE
   8  * Copyright 2009-2010 Canonical Ltd.
   9  */
  10
  11 #include <linux/errno.h>
  12 #include <linux/fdtable.h>
  13 #include <linux/fs.h>
  14 #include <linux/file.h>
  15 #include <linux/mount.h>
  16 #include <linux/syscalls.h>
  17 #include <linux/personality.h>
  18 #include <linux/xattr.h>
  19 #include <linux/user_namespace.h>
  20
  21 #include "include/audit.h"
  22 #include "include/apparmorfs.h"
  23 #include "include/cred.h"
  24 #include "include/domain.h"
  25 #include "include/file.h"
  26 #include "include/ipc.h"
  27 #include "include/match.h"
  28 #include "include/path.h"
  29 #include "include/policy.h"
  30 #include "include/policy_ns.h"
  31
  32 /**
  33  * may_change_ptraced_domain - check if can change profile on ptraced task
  34  * @to_cred: cred of task changing domain
  35  * @to_label: profile to change to  (NOT NULL)
  36  * @info: message if there is an error
  37  *
  38  * Check if current is ptraced and if so if the tracing task is allowed
  39  * to trace the new domain
  40  *
  41  * Returns: %0 or error if change not allowed
  42  */
  43 static int may_change_ptraced_domain(const struct cred *to_cred,
  44                                      struct aa_label *to_label,
  45                                      const char **info)
  46 {
  47         struct task_struct *tracer;
  48         struct aa_label *tracerl = NULL;
  49         const struct cred *tracer_cred = NULL;
  50
  51         int error = 0;
  52
  53         rcu_read_lock();
  54         tracer = ptrace_parent(current);
  55         if (tracer) {
  56                 /* released below */
  57                 tracerl = aa_get_task_label(tracer);
  58                 tracer_cred = get_task_cred(tracer);
  59         }
  60         /* not ptraced */
  61         if (!tracer || unconfined(tracerl))
  62                 goto out;
  63
  64         error = aa_may_ptrace(tracer_cred, tracerl, to_cred, to_label,
  65                               PTRACE_MODE_ATTACH);
  66
  67 out:
  68         rcu_read_unlock();
  69         aa_put_label(tracerl);
  70         put_cred(tracer_cred);
  71
  72         if (error)
  73                 *info = "ptrace prevents transition";
  74         return error;
  75 }
  76
  77 /**** TODO: dedup to aa_label_match - needs perm and dfa, merging
  78  * specifically this is an exact copy of aa_label_match except
  79  * aa_compute_perms is replaced with aa_compute_fperms
  80  * and policy->dfa with file->dfa
  81  ****/
  82 /* match a profile and its associated ns component if needed
  83  * Assumes visibility test has already been done.
  84  * If a subns profile is not to be matched should be prescreened with
  85  * visibility test.
  86  */
  87 static inline aa_state_t match_component(struct aa_profile *profile,
  88                                          struct aa_profile *tp,
  89                                          bool stack, aa_state_t state)
  90 {
  91         struct aa_ruleset *rules = list_first_entry(&profile->rules,
  92                                                     typeof(*rules), list);
  93         const char *ns_name;
  94
  95         if (stack)
  96                 state = aa_dfa_match(rules->file->dfa, state, "&");
  97         if (profile->ns == tp->ns)
  98                 return aa_dfa_match(rules->file->dfa, state, tp->base.hname);
  99
 100         /* try matching with namespace name and then profile */
 101         ns_name = aa_ns_name(profile->ns, tp->ns, true);
 102         state = aa_dfa_match_len(rules->file->dfa, state, ":", 1);
 103         state = aa_dfa_match(rules->file->dfa, state, ns_name);
 104         state = aa_dfa_match_len(rules->file->dfa, state, ":", 1);
 105         return aa_dfa_match(rules->file->dfa, state, tp->base.hname);
 106 }
 107
 108 /**
 109  * label_compound_match - find perms for full compound label
 110  * @profile: profile to find perms for
 111  * @label: label to check access permissions for
 112  * @stack: whether this is a stacking request
 113  * @state: state to start match in
 114  * @subns: whether to do permission checks on components in a subns
 115  * @request: permissions to request
 116  * @perms: perms struct to set
 117  *
 118  * Returns: 0 on success else ERROR
 119  *
 120  * For the label A//&B//&C this does the perm match for A//&B//&C
 121  * @perms should be preinitialized with allperms OR a previous permission
 122  *        check to be stacked.
 123  */
 124 static int label_compound_match(struct aa_profile *profile,
 125                                 struct aa_label *label, bool stack,
 126                                 aa_state_t state, bool subns, u32 request,
 127                                 struct aa_perms *perms)
 128 {
 129         struct aa_ruleset *rules = list_first_entry(&profile->rules,
 130                                                     typeof(*rules), list);
 131         struct aa_profile *tp;
 132         struct label_it i;
 133         struct path_cond cond = { };
 134
 135         /* find first subcomponent that is visible */
 136         label_for_each(i, label, tp) {
 137                 if (!aa_ns_visible(profile->ns, tp->ns, subns))
 138                         continue;
 139                 state = match_component(profile, tp, stack, state);
 140                 if (!state)
 141                         goto fail;
 142                 goto next;
 143         }
 144
 145         /* no component visible */
 146         *perms = allperms;
 147         return 0;
 148
 149 next:
 150         label_for_each_cont(i, label, tp) {
 151                 if (!aa_ns_visible(profile->ns, tp->ns, subns))
 152                         continue;
 153                 state = aa_dfa_match(rules->file->dfa, state, "//&");
 154                 state = match_component(profile, tp, false, state);
 155                 if (!state)
 156                         goto fail;
 157         }
 158         *perms = *(aa_lookup_fperms(rules->file, state, &cond));
 159         aa_apply_modes_to_perms(profile, perms);
 160         if ((perms->allow & request) != request)
 161                 return -EACCES;
 162
 163         return 0;
 164
 165 fail:
 166         *perms = nullperms;
 167         return -EACCES;
 168 }
 169
 170 /**
 171  * label_components_match - find perms for all subcomponents of a label
 172  * @profile: profile to find perms for
 173  * @label: label to check access permissions for
 174  * @stack: whether this is a stacking request
 175  * @start: state to start match in
 176  * @subns: whether to do permission checks on components in a subns
 177  * @request: permissions to request
 178  * @perms: an initialized perms struct to add accumulation to
 179  *
 180  * Returns: 0 on success else ERROR
 181  *
 182  * For the label A//&B//&C this does the perm match for each of A and B and C
 183  * @perms should be preinitialized with allperms OR a previous permission
 184  *        check to be stacked.
 185  */
 186 static int label_components_match(struct aa_profile *profile,
 187                                   struct aa_label *label, bool stack,
 188                                   aa_state_t start, bool subns, u32 request,
 189                                   struct aa_perms *perms)
 190 {
 191         struct aa_ruleset *rules = list_first_entry(&profile->rules,
 192                                                     typeof(*rules), list);
 193         struct aa_profile *tp;
 194         struct label_it i;
 195         struct aa_perms tmp;
 196         struct path_cond cond = { };
 197         aa_state_t state = 0;
 198
 199         /* find first subcomponent to test */
 200         label_for_each(i, label, tp) {
 201                 if (!aa_ns_visible(profile->ns, tp->ns, subns))
 202                         continue;
 203                 state = match_component(profile, tp, stack, start);
 204                 if (!state)
 205                         goto fail;
 206                 goto next;
 207         }
 208
 209         /* no subcomponents visible - no change in perms */
 210         return 0;
 211
 212 next:
 213         tmp = *(aa_lookup_fperms(rules->file, state, &cond));
 214         aa_apply_modes_to_perms(profile, &tmp);
 215         aa_perms_accum(perms, &tmp);
 216         label_for_each_cont(i, label, tp) {
 217                 if (!aa_ns_visible(profile->ns, tp->ns, subns))
 218                         continue;
 219                 state = match_component(profile, tp, stack, start);
 220                 if (!state)
 221                         goto fail;
 222                 tmp = *(aa_lookup_fperms(rules->file, state, &cond));
 223                 aa_apply_modes_to_perms(profile, &tmp);
 224                 aa_perms_accum(perms, &tmp);
 225         }
 226
 227         if ((perms->allow & request) != request)
 228                 return -EACCES;
 229
 230         return 0;
 231
 232 fail:
 233         *perms = nullperms;
 234         return -EACCES;
 235 }
 236
 237 /**
 238  * label_match - do a multi-component label match
 239  * @profile: profile to match against (NOT NULL)
 240  * @label: label to match (NOT NULL)
 241  * @stack: whether this is a stacking request
 242  * @state: state to start in
 243  * @subns: whether to match subns components
 244  * @request: permission request
 245  * @perms: Returns computed perms (NOT NULL)
 246  *
 247  * Returns: the state the match finished in, may be the none matching state
 248  */
 249 static int label_match(struct aa_profile *profile, struct aa_label *label,
 250                        bool stack, aa_state_t state, bool subns, u32 request,
 251                        struct aa_perms *perms)
 252 {
 253         int error;
 254
 255         *perms = nullperms;
 256         error = label_compound_match(profile, label, stack, state, subns,
 257                                      request, perms);
 258         if (!error)
 259                 return error;
 260
 261         *perms = allperms;
 262         return label_components_match(profile, label, stack, state, subns,
 263                                       request, perms);
 264 }
 265
 266 /******* end TODO: dedup *****/
 267
 268 /**
 269  * change_profile_perms - find permissions for change_profile
 270  * @profile: the current profile  (NOT NULL)
 271  * @target: label to transition to (NOT NULL)
 272  * @stack: whether this is a stacking request
 273  * @request: requested perms
 274  * @start: state to start matching in
 275  * @perms: Returns computed perms (NOT NULL)
 276  *
 277  *
 278  * Returns: permission set
 279  *
 280  * currently only matches full label A//&B//&C or individual components A, B, C
 281  * not arbitrary combinations. Eg. A//&B, C
 282  */
 283 static int change_profile_perms(struct aa_profile *profile,
 284                                 struct aa_label *target, bool stack,
 285                                 u32 request, aa_state_t start,
 286                                 struct aa_perms *perms)
 287 {
 288         if (profile_unconfined(profile)) {
 289                 perms->allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC;
 290                 perms->audit = perms->quiet = perms->kill = 0;
 291                 return 0;
 292         }
 293
 294         /* TODO: add profile in ns screening */
 295         return label_match(profile, target, stack, start, true, request, perms);
 296 }
 297
 298 /**
 299  * aa_xattrs_match - check whether a file matches the xattrs defined in profile
 300  * @bprm: binprm struct for the process to validate
 301  * @profile: profile to match against (NOT NULL)
 302  * @state: state to start match in
 303  *
 304  * Returns: number of extended attributes that matched, or < 0 on error
 305  */
 306 static int aa_xattrs_match(const struct linux_binprm *bprm,
 307                            struct aa_profile *profile, aa_state_t state)
 308 {
 309         int i;
 310         struct dentry *d;
 311         char *value = NULL;
 312         struct aa_attachment *attach = &profile->attach;
 313         int size, value_size = 0, ret = attach->xattr_count;
 314
 315         if (!bprm || !attach->xattr_count)
 316                 return 0;
 317         might_sleep();
 318
 319         /* transition from exec match to xattr set */
 320         state = aa_dfa_outofband_transition(attach->xmatch->dfa, state);
 321         d = bprm->file->f_path.dentry;
 322
 323         for (i = 0; i < attach->xattr_count; i++) {
 324                 size = vfs_getxattr_alloc(&nop_mnt_idmap, d, attach->xattrs[i],
 325                                           &value, value_size, GFP_KERNEL);
 326                 if (size >= 0) {
 327                         u32 index, perm;
 328
 329                         /*
 330                          * Check the xattr presence before value. This ensure
 331                          * that not present xattr can be distinguished from a 0
 332                          * length value or rule that matches any value
 333                          */
 334                         state = aa_dfa_null_transition(attach->xmatch->dfa,
 335                                                        state);
 336                         /* Check xattr value */
 337                         state = aa_dfa_match_len(attach->xmatch->dfa, state,
 338                                                  value, size);
 339                         index = ACCEPT_TABLE(attach->xmatch->dfa)[state];
 340                         perm = attach->xmatch->perms[index].allow;
 341                         if (!(perm & MAY_EXEC)) {
 342                                 ret = -EINVAL;
 343                                 goto out;
 344                         }
 345                 }
 346                 /* transition to next element */
 347                 state = aa_dfa_outofband_transition(attach->xmatch->dfa, state);
 348                 if (size < 0) {
 349                         /*
 350                          * No xattr match, so verify if transition to
 351                          * next element was valid. IFF so the xattr
 352                          * was optional.
 353                          */
 354                         if (!state) {
 355                                 ret = -EINVAL;
 356                                 goto out;
 357                         }
 358                         /* don't count missing optional xattr as matched */
 359                         ret--;
 360                 }
 361         }
 362
 363 out:
 364         kfree(value);
 365         return ret;
 366 }
 367
 368 /**
 369  * find_attach - do attachment search for unconfined processes
 370  * @bprm: binprm structure of transitioning task
 371  * @ns: the current namespace  (NOT NULL)
 372  * @head: profile list to walk  (NOT NULL)
 373  * @name: to match against  (NOT NULL)
 374  * @info: info message if there was an error (NOT NULL)
 375  *
 376  * Do a linear search on the profiles in the list.  There is a matching
 377  * preference where an exact match is preferred over a name which uses
 378  * expressions to match, and matching expressions with the greatest
 379  * xmatch_len are preferred.
 380  *
 381  * Requires: @head not be shared or have appropriate locks held
 382  *
 383  * Returns: label or NULL if no match found
 384  */
 385 static struct aa_label *find_attach(const struct linux_binprm *bprm,
 386                                     struct aa_ns *ns, struct list_head *head,
 387                                     const char *name, const char **info)
 388 {
 389         int candidate_len = 0, candidate_xattrs = 0;
 390         bool conflict = false;
 391         struct aa_profile *profile, *candidate = NULL;
 392
 393         AA_BUG(!name);
 394         AA_BUG(!head);
 395
 396         rcu_read_lock();
 397 restart:
 398         list_for_each_entry_rcu(profile, head, base.list) {
 399                 struct aa_attachment *attach = &profile->attach;
 400
 401                 if (profile->label.flags & FLAG_NULL &&
 402                     &profile->label == ns_unconfined(profile->ns))
 403                         continue;
 404
 405                 /* Find the "best" matching profile. Profiles must
 406                  * match the path and extended attributes (if any)
 407                  * associated with the file. A more specific path
 408                  * match will be preferred over a less specific one,
 409                  * and a match with more matching extended attributes
 410                  * will be preferred over one with fewer. If the best
 411                  * match has both the same level of path specificity
 412                  * and the same number of matching extended attributes
 413                  * as another profile, signal a conflict and refuse to
 414                  * match.
 415                  */
 416                 if (attach->xmatch->dfa) {
 417                         unsigned int count;
 418                         aa_state_t state;
 419                         u32 index, perm;
 420
 421                         state = aa_dfa_leftmatch(attach->xmatch->dfa,
 422                                         attach->xmatch->start[AA_CLASS_XMATCH],
 423                                         name, &count);
 424                         index = ACCEPT_TABLE(attach->xmatch->dfa)[state];
 425                         perm = attach->xmatch->perms[index].allow;
 426                         /* any accepting state means a valid match. */
 427                         if (perm & MAY_EXEC) {
 428                                 int ret = 0;
 429
 430                                 if (count < candidate_len)
 431                                         continue;
 432
 433                                 if (bprm && attach->xattr_count) {
 434                                         long rev = READ_ONCE(ns->revision);
 435
 436                                         if (!aa_get_profile_not0(profile))
 437                                                 goto restart;
 438                                         rcu_read_unlock();
 439                                         ret = aa_xattrs_match(bprm, profile,
 440                                                               state);
 441                                         rcu_read_lock();
 442                                         aa_put_profile(profile);
 443                                         if (rev !=
 444                                             READ_ONCE(ns->revision))
 445                                                 /* policy changed */
 446                                                 goto restart;
 447                                         /*
 448                                          * Fail matching if the xattrs don't
 449                                          * match
 450                                          */
 451                                         if (ret < 0)
 452                                                 continue;
 453                                 }
 454                                 /*
 455                                  * TODO: allow for more flexible best match
 456                                  *
 457                                  * The new match isn't more specific
 458                                  * than the current best match
 459                                  */
 460                                 if (count == candidate_len &&
 461                                     ret <= candidate_xattrs) {
 462                                         /* Match is equivalent, so conflict */
 463                                         if (ret == candidate_xattrs)
 464                                                 conflict = true;
 465                                         continue;
 466                                 }
 467
 468                                 /* Either the same length with more matching
 469                                  * xattrs, or a longer match
 470                                  */
 471                                 candidate = profile;
 472                                 candidate_len = max(count, attach->xmatch_len);
 473                                 candidate_xattrs = ret;
 474                                 conflict = false;
 475                         }
 476                 } else if (!strcmp(profile->base.name, name)) {
 477                         /*
 478                          * old exact non-re match, without conditionals such
 479                          * as xattrs. no more searching required
 480                          */
 481                         candidate = profile;
 482                         goto out;
 483                 }
 484         }
 485
 486         if (!candidate || conflict) {
 487                 if (conflict)
 488                         *info = "conflicting profile attachments";
 489                 rcu_read_unlock();
 490                 return NULL;
 491         }
 492
 493 out:
 494         candidate = aa_get_newest_profile(candidate);
 495         rcu_read_unlock();
 496
 497         return &candidate->label;
 498 }
 499
 500 static const char *next_name(int xtype, const char *name)
 501 {
 502         return NULL;
 503 }
 504
 505 /**
 506  * x_table_lookup - lookup an x transition name via transition table
 507  * @profile: current profile (NOT NULL)
 508  * @xindex: index into x transition table
 509  * @name: returns: name tested to find label (NOT NULL)
 510  *
 511  * Returns: refcounted label, or NULL on failure (MAYBE NULL)
 512  */
 513 struct aa_label *x_table_lookup(struct aa_profile *profile, u32 xindex,
 514                                 const char **name)
 515 {
 516         struct aa_ruleset *rules = list_first_entry(&profile->rules,
 517                                                     typeof(*rules), list);
 518         struct aa_label *label = NULL;
 519         u32 xtype = xindex & AA_X_TYPE_MASK;
 520         int index = xindex & AA_X_INDEX_MASK;
 521
 522         AA_BUG(!name);
 523
 524         /* index is guaranteed to be in range, validated at load time */
 525         /* TODO: move lookup parsing to unpack time so this is a straight
 526          *       index into the resultant label
 527          */
 528         for (*name = rules->file->trans.table[index]; !label && *name;
 529              *name = next_name(xtype, *name)) {
 530                 if (xindex & AA_X_CHILD) {
 531                         struct aa_profile *new_profile;
 532                         /* release by caller */
 533                         new_profile = aa_find_child(profile, *name);
 534                         if (new_profile)
 535                                 label = &new_profile->label;
 536                         continue;
 537                 }
 538                 label = aa_label_parse(&profile->label, *name, GFP_KERNEL,
 539                                        true, false);
 540                 if (IS_ERR(label))
 541                         label = NULL;
 542         }
 543
 544         /* released by caller */
 545
 546         return label;
 547 }
 548
 549 /**
 550  * x_to_label - get target label for a given xindex
 551  * @profile: current profile  (NOT NULL)
 552  * @bprm: binprm structure of transitioning task
 553  * @name: name to lookup (NOT NULL)
 554  * @xindex: index into x transition table
 555  * @lookupname: returns: name used in lookup if one was specified (NOT NULL)
 556  * @info: info message if there was an error (NOT NULL)
 557  *
 558  * find label for a transition index
 559  *
 560  * Returns: refcounted label or NULL if not found available
 561  */
 562 static struct aa_label *x_to_label(struct aa_profile *profile,
 563                                    const struct linux_binprm *bprm,
 564                                    const char *name, u32 xindex,
 565                                    const char **lookupname,
 566                                    const char **info)
 567 {
 568         struct aa_ruleset *rules = list_first_entry(&profile->rules,
 569                                                     typeof(*rules), list);
 570         struct aa_label *new = NULL;
 571         struct aa_ns *ns = profile->ns;
 572         u32 xtype = xindex & AA_X_TYPE_MASK;
 573         const char *stack = NULL;
 574
 575         switch (xtype) {
 576         case AA_X_NONE:
 577                 /* fail exec unless ix || ux fallback - handled by caller */
 578                 *lookupname = NULL;
 579                 break;
 580         case AA_X_TABLE:
 581                 /* TODO: fix when perm mapping done at unload */
 582                 stack = rules->file->trans.table[xindex & AA_X_INDEX_MASK];
 583                 if (*stack != '&') {
 584                         /* released by caller */
 585                         new = x_table_lookup(profile, xindex, lookupname);
 586                         stack = NULL;
 587                         break;
 588                 }
 589                 fallthrough;    /* to X_NAME */
 590         case AA_X_NAME:
 591                 if (xindex & AA_X_CHILD)
 592                         /* released by caller */
 593                         new = find_attach(bprm, ns, &profile->base.profiles,
 594                                           name, info);
 595                 else
 596                         /* released by caller */
 597                         new = find_attach(bprm, ns, &ns->base.profiles,
 598                                           name, info);
 599                 *lookupname = name;
 600                 break;
 601         }
 602
 603         if (!new) {
 604                 if (xindex & AA_X_INHERIT) {
 605                         /* (p|c|n)ix - don't change profile but do
 606                          * use the newest version
 607                          */
 608                         *info = "ix fallback";
 609                         /* no profile && no error */
 610                         new = aa_get_newest_label(&profile->label);
 611                 } else if (xindex & AA_X_UNCONFINED) {
 612                         new = aa_get_newest_label(ns_unconfined(profile->ns));
 613                         *info = "ux fallback";
 614                 }
 615         }
 616
 617         if (new && stack) {
 618                 /* base the stack on post domain transition */
 619                 struct aa_label *base = new;
 620
 621                 new = aa_label_parse(base, stack, GFP_KERNEL, true, false);
 622                 if (IS_ERR(new))
 623                         new = NULL;
 624                 aa_put_label(base);
 625         }
 626
 627         /* released by caller */
 628         return new;
 629 }
 630
 631 static struct aa_label *profile_transition(const struct cred *subj_cred,
 632                                            struct aa_profile *profile,
 633                                            const struct linux_binprm *bprm,
 634                                            char *buffer, struct path_cond *cond,
 635                                            bool *secure_exec)
 636 {
 637         struct aa_ruleset *rules = list_first_entry(&profile->rules,
 638                                                     typeof(*rules), list);
 639         struct aa_label *new = NULL;
 640         const char *info = NULL, *name = NULL, *target = NULL;
 641         aa_state_t state = rules->file->start[AA_CLASS_FILE];
 642         struct aa_perms perms = {};
 643         bool nonewprivs = false;
 644         int error = 0;
 645
 646         AA_BUG(!profile);
 647         AA_BUG(!bprm);
 648         AA_BUG(!buffer);
 649
 650         error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
 651                              &name, &info, profile->disconnected);
 652         if (error) {
 653                 if (profile_unconfined(profile) ||
 654                     (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
 655                         AA_DEBUG("name lookup ix on error");
 656                         error = 0;
 657                         new = aa_get_newest_label(&profile->label);
 658                 }
 659                 name = bprm->filename;
 660                 goto audit;
 661         }
 662
 663         if (profile_unconfined(profile)) {
 664                 new = find_attach(bprm, profile->ns,
 665                                   &profile->ns->base.profiles, name, &info);
 666                 if (new) {
 667                         AA_DEBUG("unconfined attached to new label");
 668                         return new;
 669                 }
 670                 AA_DEBUG("unconfined exec no attachment");
 671                 return aa_get_newest_label(&profile->label);
 672         }
 673
 674         /* find exec permissions for name */
 675         state = aa_str_perms(rules->file, state, name, cond, &perms);
 676         if (perms.allow & MAY_EXEC) {
 677                 /* exec permission determine how to transition */
 678                 new = x_to_label(profile, bprm, name, perms.xindex, &target,
 679                                  &info);
 680                 if (new && new->proxy == profile->label.proxy && info) {
 681                         /* hack ix fallback - improve how this is detected */
 682                         goto audit;
 683                 } else if (!new) {
 684                         error = -EACCES;
 685                         info = "profile transition not found";
 686                         /* remove MAY_EXEC to audit as failure */
 687                         perms.allow &= ~MAY_EXEC;
 688                 }
 689         } else if (COMPLAIN_MODE(profile)) {
 690                 /* no exec permission - learning mode */
 691                 struct aa_profile *new_profile = NULL;
 692
 693                 new_profile = aa_new_learning_profile(profile, false, name,
 694                                                       GFP_KERNEL);
 695                 if (!new_profile) {
 696                         error = -ENOMEM;
 697                         info = "could not create null profile";
 698                 } else {
 699                         error = -EACCES;
 700                         new = &new_profile->label;
 701                 }
 702                 perms.xindex |= AA_X_UNSAFE;
 703         } else
 704                 /* fail exec */
 705                 error = -EACCES;
 706
 707         if (!new)
 708                 goto audit;
 709
 710
 711         if (!(perms.xindex & AA_X_UNSAFE)) {
 712                 if (DEBUG_ON) {
 713                         dbg_printk("apparmor: scrubbing environment variables"
 714                                    " for %s profile=", name);
 715                         aa_label_printk(new, GFP_KERNEL);
 716                         dbg_printk("\n");
 717                 }
 718                 *secure_exec = true;
 719         }
 720
 721 audit:
 722         aa_audit_file(subj_cred, profile, &perms, OP_EXEC, MAY_EXEC, name,
 723                       target, new,
 724                       cond->uid, info, error);
 725         if (!new || nonewprivs) {
 726                 aa_put_label(new);
 727                 return ERR_PTR(error);
 728         }
 729
 730         return new;
 731 }
 732
 733 static int profile_onexec(const struct cred *subj_cred,
 734                           struct aa_profile *profile, struct aa_label *onexec,
 735                           bool stack, const struct linux_binprm *bprm,
 736                           char *buffer, struct path_cond *cond,
 737                           bool *secure_exec)
 738 {
 739         struct aa_ruleset *rules = list_first_entry(&profile->rules,
 740                                                     typeof(*rules), list);
 741         aa_state_t state = rules->file->start[AA_CLASS_FILE];
 742         struct aa_perms perms = {};
 743         const char *xname = NULL, *info = "change_profile onexec";
 744         int error = -EACCES;
 745
 746         AA_BUG(!profile);
 747         AA_BUG(!onexec);
 748         AA_BUG(!bprm);
 749         AA_BUG(!buffer);
 750
 751         if (profile_unconfined(profile)) {
 752                 /* change_profile on exec already granted */
 753                 /*
 754                  * NOTE: Domain transitions from unconfined are allowed
 755                  * even when no_new_privs is set because this aways results
 756                  * in a further reduction of permissions.
 757                  */
 758                 return 0;
 759         }
 760
 761         error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
 762                              &xname, &info, profile->disconnected);
 763         if (error) {
 764                 if (profile_unconfined(profile) ||
 765                     (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
 766                         AA_DEBUG("name lookup ix on error");
 767                         error = 0;
 768                 }
 769                 xname = bprm->filename;
 770                 goto audit;
 771         }
 772
 773         /* find exec permissions for name */
 774         state = aa_str_perms(rules->file, state, xname, cond, &perms);
 775         if (!(perms.allow & AA_MAY_ONEXEC)) {
 776                 info = "no change_onexec valid for executable";
 777                 goto audit;
 778         }
 779         /* test if this exec can be paired with change_profile onexec.
 780          * onexec permission is linked to exec with a standard pairing
 781          * exec\0change_profile
 782          */
 783         state = aa_dfa_null_transition(rules->file->dfa, state);
 784         error = change_profile_perms(profile, onexec, stack, AA_MAY_ONEXEC,
 785                                      state, &perms);
 786         if (error) {
 787                 perms.allow &= ~AA_MAY_ONEXEC;
 788                 goto audit;
 789         }
 790
 791         if (!(perms.xindex & AA_X_UNSAFE)) {
 792                 if (DEBUG_ON) {
 793                         dbg_printk("apparmor: scrubbing environment "
 794                                    "variables for %s label=", xname);
 795                         aa_label_printk(onexec, GFP_KERNEL);
 796                         dbg_printk("\n");
 797                 }
 798                 *secure_exec = true;
 799         }
 800
 801 audit:
 802         return aa_audit_file(subj_cred, profile, &perms, OP_EXEC,
 803                              AA_MAY_ONEXEC, xname,
 804                              NULL, onexec, cond->uid, info, error);
 805 }
 806
 807 /* ensure none ns domain transitions are correctly applied with onexec */
 808
 809 static struct aa_label *handle_onexec(const struct cred *subj_cred,
 810                                       struct aa_label *label,
 811                                       struct aa_label *onexec, bool stack,
 812                                       const struct linux_binprm *bprm,
 813                                       char *buffer, struct path_cond *cond,
 814                                       bool *unsafe)
 815 {
 816         struct aa_profile *profile;
 817         struct aa_label *new;
 818         int error;
 819
 820         AA_BUG(!label);
 821         AA_BUG(!onexec);
 822         AA_BUG(!bprm);
 823         AA_BUG(!buffer);
 824
 825         if (!stack) {
 826                 error = fn_for_each_in_ns(label, profile,
 827                                 profile_onexec(subj_cred, profile, onexec, stack,
 828                                                bprm, buffer, cond, unsafe));
 829                 if (error)
 830                         return ERR_PTR(error);
 831                 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
 832                                 aa_get_newest_label(onexec),
 833                                 profile_transition(subj_cred, profile, bprm,
 834                                                    buffer,
 835                                                    cond, unsafe));
 836
 837         } else {
 838                 /* TODO: determine how much we want to loosen this */
 839                 error = fn_for_each_in_ns(label, profile,
 840                                 profile_onexec(subj_cred, profile, onexec, stack, bprm,
 841                                                buffer, cond, unsafe));
 842                 if (error)
 843                         return ERR_PTR(error);
 844                 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
 845                                 aa_label_merge(&profile->label, onexec,
 846                                                GFP_KERNEL),
 847                                 profile_transition(subj_cred, profile, bprm,
 848                                                    buffer,
 849                                                    cond, unsafe));
 850         }
 851
 852         if (new)
 853                 return new;
 854
 855         /* TODO: get rid of GLOBAL_ROOT_UID */
 856         error = fn_for_each_in_ns(label, profile,
 857                         aa_audit_file(subj_cred, profile, &nullperms,
 858                                       OP_CHANGE_ONEXEC,
 859                                       AA_MAY_ONEXEC, bprm->filename, NULL,
 860                                       onexec, GLOBAL_ROOT_UID,
 861                                       "failed to build target label", -ENOMEM));
 862         return ERR_PTR(error);
 863 }
 864
 865 /**
 866  * apparmor_bprm_creds_for_exec - Update the new creds on the bprm struct
 867  * @bprm: binprm for the exec  (NOT NULL)
 868  *
 869  * Returns: %0 or error on failure
 870  *
 871  * TODO: once the other paths are done see if we can't refactor into a fn
 872  */
 873 int apparmor_bprm_creds_for_exec(struct linux_binprm *bprm)
 874 {
 875         struct aa_task_ctx *ctx;
 876         struct aa_label *label, *new = NULL;
 877         const struct cred *subj_cred;
 878         struct aa_profile *profile;
 879         char *buffer = NULL;
 880         const char *info = NULL;
 881         int error = 0;
 882         bool unsafe = false;
 883         vfsuid_t vfsuid = i_uid_into_vfsuid(file_mnt_idmap(bprm->file),
 884                                             file_inode(bprm->file));
 885         struct path_cond cond = {
 886                 vfsuid_into_kuid(vfsuid),
 887                 file_inode(bprm->file)->i_mode
 888         };
 889
 890         subj_cred = current_cred();
 891         ctx = task_ctx(current);
 892         AA_BUG(!cred_label(bprm->cred));
 893         AA_BUG(!ctx);
 894
 895         label = aa_get_newest_label(cred_label(bprm->cred));
 896
 897         /*
 898          * Detect no new privs being set, and store the label it
 899          * occurred under. Ideally this would happen when nnp
 900          * is set but there isn't a good way to do that yet.
 901          *
 902          * Testing for unconfined must be done before the subset test
 903          */
 904         if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) && !unconfined(label) &&
 905             !ctx->nnp)
 906                 ctx->nnp = aa_get_label(label);
 907
 908         /* buffer freed below, name is pointer into buffer */
 909         buffer = aa_get_buffer(false);
 910         if (!buffer) {
 911                 error = -ENOMEM;
 912                 goto done;
 913         }
 914
 915         /* Test for onexec first as onexec override other x transitions. */
 916         if (ctx->onexec)
 917                 new = handle_onexec(subj_cred, label, ctx->onexec, ctx->token,
 918                                     bprm, buffer, &cond, &unsafe);
 919         else
 920                 new = fn_label_build(label, profile, GFP_KERNEL,
 921                                 profile_transition(subj_cred, profile, bprm,
 922                                                    buffer,
 923                                                    &cond, &unsafe));
 924
 925         AA_BUG(!new);
 926         if (IS_ERR(new)) {
 927                 error = PTR_ERR(new);
 928                 goto done;
 929         } else if (!new) {
 930                 error = -ENOMEM;
 931                 goto done;
 932         }
 933
 934         /* Policy has specified a domain transitions. If no_new_privs and
 935          * confined ensure the transition is to confinement that is subset
 936          * of the confinement when the task entered no new privs.
 937          *
 938          * NOTE: Domain transitions from unconfined and to stacked
 939          * subsets are allowed even when no_new_privs is set because this
 940          * aways results in a further reduction of permissions.
 941          */
 942         if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) &&
 943             !unconfined(label) &&
 944             !aa_label_is_unconfined_subset(new, ctx->nnp)) {
 945                 error = -EPERM;
 946                 info = "no new privs";
 947                 goto audit;
 948         }
 949
 950         if (bprm->unsafe & LSM_UNSAFE_SHARE) {
 951                 /* FIXME: currently don't mediate shared state */
 952                 ;
 953         }
 954
 955         if (bprm->unsafe & (LSM_UNSAFE_PTRACE)) {
 956                 /* TODO: test needs to be profile of label to new */
 957                 error = may_change_ptraced_domain(bprm->cred, new, &info);
 958                 if (error)
 959                         goto audit;
 960         }
 961
 962         if (unsafe) {
 963                 if (DEBUG_ON) {
 964                         dbg_printk("scrubbing environment variables for %s "
 965                                    "label=", bprm->filename);
 966                         aa_label_printk(new, GFP_KERNEL);
 967                         dbg_printk("\n");
 968                 }
 969                 bprm->secureexec = 1;
 970         }
 971
 972         if (label->proxy != new->proxy) {
 973                 /* when transitioning clear unsafe personality bits */
 974                 if (DEBUG_ON) {
 975                         dbg_printk("apparmor: clearing unsafe personality "
 976                                    "bits. %s label=", bprm->filename);
 977                         aa_label_printk(new, GFP_KERNEL);
 978                         dbg_printk("\n");
 979                 }
 980                 bprm->per_clear |= PER_CLEAR_ON_SETID;
 981         }
 982         aa_put_label(cred_label(bprm->cred));
 983         /* transfer reference, released when cred is freed */
 984         set_cred_label(bprm->cred, new);
 985
 986 done:
 987         aa_put_label(label);
 988         aa_put_buffer(buffer);
 989
 990         return error;
 991
 992 audit:
 993         error = fn_for_each(label, profile,
 994                         aa_audit_file(current_cred(), profile, &nullperms,
 995                                       OP_EXEC, MAY_EXEC,
 996                                       bprm->filename, NULL, new,
 997                                       vfsuid_into_kuid(vfsuid), info, error));
 998         aa_put_label(new);
 999         goto done;
1000 }
1001
1002 /*
1003  * Functions for self directed profile change
1004  */
1005
1006
1007 /* helper fn for change_hat
1008  *
1009  * Returns: label for hat transition OR ERR_PTR.  Does NOT return NULL
1010  */
1011 static struct aa_label *build_change_hat(const struct cred *subj_cred,
1012                                          struct aa_profile *profile,
1013                                          const char *name, bool sibling)
1014 {
1015         struct aa_profile *root, *hat = NULL;
1016         const char *info = NULL;
1017         int error = 0;
1018
1019         if (sibling && PROFILE_IS_HAT(profile)) {
1020                 root = aa_get_profile_rcu(&profile->parent);
1021         } else if (!sibling && !PROFILE_IS_HAT(profile)) {
1022                 root = aa_get_profile(profile);
1023         } else {
1024                 info = "conflicting target types";
1025                 error = -EPERM;
1026                 goto audit;
1027         }
1028
1029         hat = aa_find_child(root, name);
1030         if (!hat) {
1031                 error = -ENOENT;
1032                 if (COMPLAIN_MODE(profile)) {
1033                         hat = aa_new_learning_profile(profile, true, name,
1034                                                       GFP_KERNEL);
1035                         if (!hat) {
1036                                 info = "failed null profile create";
1037                                 error = -ENOMEM;
1038                         }
1039                 }
1040         }
1041         aa_put_profile(root);
1042
1043 audit:
1044         aa_audit_file(subj_cred, profile, &nullperms, OP_CHANGE_HAT,
1045                       AA_MAY_CHANGEHAT,
1046                       name, hat ? hat->base.hname : NULL,
1047                       hat ? &hat->label : NULL, GLOBAL_ROOT_UID, info,
1048                       error);
1049         if (!hat || (error && error != -ENOENT))
1050                 return ERR_PTR(error);
1051         /* if hat && error - complain mode, already audited and we adjust for
1052          * complain mode allow by returning hat->label
1053          */
1054         return &hat->label;
1055 }
1056
1057 /* helper fn for changing into a hat
1058  *
1059  * Returns: label for hat transition or ERR_PTR. Does not return NULL
1060  */
1061 static struct aa_label *change_hat(const struct cred *subj_cred,
1062                                    struct aa_label *label, const char *hats[],
1063                                    int count, int flags)
1064 {
1065         struct aa_profile *profile, *root, *hat = NULL;
1066         struct aa_label *new;
1067         struct label_it it;
1068         bool sibling = false;
1069         const char *name, *info = NULL;
1070         int i, error;
1071
1072         AA_BUG(!label);
1073         AA_BUG(!hats);
1074         AA_BUG(count < 1);
1075
1076         if (PROFILE_IS_HAT(labels_profile(label)))
1077                 sibling = true;
1078
1079         /*find first matching hat */
1080         for (i = 0; i < count && !hat; i++) {
1081                 name = hats[i];
1082                 label_for_each_in_ns(it, labels_ns(label), label, profile) {
1083                         if (sibling && PROFILE_IS_HAT(profile)) {
1084                                 root = aa_get_profile_rcu(&profile->parent);
1085                         } else if (!sibling && !PROFILE_IS_HAT(profile)) {
1086                                 root = aa_get_profile(profile);
1087                         } else {        /* conflicting change type */
1088                                 info = "conflicting targets types";
1089                                 error = -EPERM;
1090                                 goto fail;
1091                         }
1092                         hat = aa_find_child(root, name);
1093                         aa_put_profile(root);
1094                         if (!hat) {
1095                                 if (!COMPLAIN_MODE(profile))
1096                                         goto outer_continue;
1097                                 /* complain mode succeed as if hat */
1098                         } else if (!PROFILE_IS_HAT(hat)) {
1099                                 info = "target not hat";
1100                                 error = -EPERM;
1101                                 aa_put_profile(hat);
1102                                 goto fail;
1103                         }
1104                         aa_put_profile(hat);
1105                 }
1106                 /* found a hat for all profiles in ns */
1107                 goto build;
1108 outer_continue:
1109         ;
1110         }
1111         /* no hats that match, find appropriate error
1112          *
1113          * In complain mode audit of the failure is based off of the first
1114          * hat supplied.  This is done due how userspace interacts with
1115          * change_hat.
1116          */
1117         name = NULL;
1118         label_for_each_in_ns(it, labels_ns(label), label, profile) {
1119                 if (!list_empty(&profile->base.profiles)) {
1120                         info = "hat not found";
1121                         error = -ENOENT;
1122                         goto fail;
1123                 }
1124         }
1125         info = "no hats defined";
1126         error = -ECHILD;
1127
1128 fail:
1129         label_for_each_in_ns(it, labels_ns(label), label, profile) {
1130                 /*
1131                  * no target as it has failed to be found or built
1132                  *
1133                  * change_hat uses probing and should not log failures
1134                  * related to missing hats
1135                  */
1136                 /* TODO: get rid of GLOBAL_ROOT_UID */
1137                 if (count > 1 || COMPLAIN_MODE(profile)) {
1138                         aa_audit_file(subj_cred, profile, &nullperms,
1139                                       OP_CHANGE_HAT,
1140                                       AA_MAY_CHANGEHAT, name, NULL, NULL,
1141                                       GLOBAL_ROOT_UID, info, error);
1142                 }
1143         }
1144         return ERR_PTR(error);
1145
1146 build:
1147         new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
1148                                    build_change_hat(subj_cred, profile, name,
1149                                                     sibling),
1150                                    aa_get_label(&profile->label));
1151         if (!new) {
1152                 info = "label build failed";
1153                 error = -ENOMEM;
1154                 goto fail;
1155         } /* else if (IS_ERR) build_change_hat has logged error so return new */
1156
1157         return new;
1158 }
1159
1160 /**
1161  * aa_change_hat - change hat to/from subprofile
1162  * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0)
1163  * @count: number of hat names in @hats
1164  * @token: magic value to validate the hat change
1165  * @flags: flags affecting behavior of the change
1166  *
1167  * Returns %0 on success, error otherwise.
1168  *
1169  * Change to the first profile specified in @hats that exists, and store
1170  * the @hat_magic in the current task context.  If the count == 0 and the
1171  * @token matches that stored in the current task context, return to the
1172  * top level profile.
1173  *
1174  * change_hat only applies to profiles in the current ns, and each profile
1175  * in the ns must make the same transition otherwise change_hat will fail.
1176  */
1177 int aa_change_hat(const char *hats[], int count, u64 token, int flags)
1178 {
1179         const struct cred *subj_cred;
1180         struct aa_task_ctx *ctx = task_ctx(current);
1181         struct aa_label *label, *previous, *new = NULL, *target = NULL;
1182         struct aa_profile *profile;
1183         struct aa_perms perms = {};
1184         const char *info = NULL;
1185         int error = 0;
1186
1187         /* released below */
1188         subj_cred = get_current_cred();
1189         label = aa_get_newest_cred_label(subj_cred);
1190         previous = aa_get_newest_label(ctx->previous);
1191
1192         /*
1193          * Detect no new privs being set, and store the label it
1194          * occurred under. Ideally this would happen when nnp
1195          * is set but there isn't a good way to do that yet.
1196          *
1197          * Testing for unconfined must be done before the subset test
1198          */
1199         if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
1200                 ctx->nnp = aa_get_label(label);
1201
1202         if (unconfined(label)) {
1203                 info = "unconfined can not change_hat";
1204                 error = -EPERM;
1205                 goto fail;
1206         }
1207
1208         if (count) {
1209                 new = change_hat(subj_cred, label, hats, count, flags);
1210                 AA_BUG(!new);
1211                 if (IS_ERR(new)) {
1212                         error = PTR_ERR(new);
1213                         new = NULL;
1214                         /* already audited */
1215                         goto out;
1216                 }
1217
1218                 /* target cred is the same as current except new label */
1219                 error = may_change_ptraced_domain(subj_cred, new, &info);
1220                 if (error)
1221                         goto fail;
1222
1223                 /*
1224                  * no new privs prevents domain transitions that would
1225                  * reduce restrictions.
1226                  */
1227                 if (task_no_new_privs(current) && !unconfined(label) &&
1228                     !aa_label_is_unconfined_subset(new, ctx->nnp)) {
1229                         /* not an apparmor denial per se, so don't log it */
1230                         AA_DEBUG("no_new_privs - change_hat denied");
1231                         error = -EPERM;
1232                         goto out;
1233                 }
1234
1235                 if (flags & AA_CHANGE_TEST)
1236                         goto out;
1237
1238                 target = new;
1239                 error = aa_set_current_hat(new, token);
1240                 if (error == -EACCES)
1241                         /* kill task in case of brute force attacks */
1242                         goto kill;
1243         } else if (previous && !(flags & AA_CHANGE_TEST)) {
1244                 /*
1245                  * no new privs prevents domain transitions that would
1246                  * reduce restrictions.
1247                  */
1248                 if (task_no_new_privs(current) && !unconfined(label) &&
1249                     !aa_label_is_unconfined_subset(previous, ctx->nnp)) {
1250                         /* not an apparmor denial per se, so don't log it */
1251                         AA_DEBUG("no_new_privs - change_hat denied");
1252                         error = -EPERM;
1253                         goto out;
1254                 }
1255
1256                 /* Return to saved label.  Kill task if restore fails
1257                  * to avoid brute force attacks
1258                  */
1259                 target = previous;
1260                 error = aa_restore_previous_label(token);
1261                 if (error) {
1262                         if (error == -EACCES)
1263                                 goto kill;
1264                         goto fail;
1265                 }
1266         } /* else ignore @flags && restores when there is no saved profile */
1267
1268 out:
1269         aa_put_label(new);
1270         aa_put_label(previous);
1271         aa_put_label(label);
1272         put_cred(subj_cred);
1273
1274         return error;
1275
1276 kill:
1277         info = "failed token match";
1278         perms.kill = AA_MAY_CHANGEHAT;
1279
1280 fail:
1281         fn_for_each_in_ns(label, profile,
1282                 aa_audit_file(subj_cred, profile, &perms, OP_CHANGE_HAT,
1283                               AA_MAY_CHANGEHAT, NULL, NULL, target,
1284                               GLOBAL_ROOT_UID, info, error));
1285
1286         goto out;
1287 }
1288
1289
1290 static int change_profile_perms_wrapper(const char *op, const char *name,
1291                                         const struct cred *subj_cred,
1292                                         struct aa_profile *profile,
1293                                         struct aa_label *target, bool stack,
1294                                         u32 request, struct aa_perms *perms)
1295 {
1296         struct aa_ruleset *rules = list_first_entry(&profile->rules,
1297                                                     typeof(*rules), list);
1298         const char *info = NULL;
1299         int error = 0;
1300
1301         if (!error)
1302                 error = change_profile_perms(profile, target, stack, request,
1303                                              rules->file->start[AA_CLASS_FILE],
1304                                              perms);
1305         if (error)
1306                 error = aa_audit_file(subj_cred, profile, perms, op, request,
1307                                       name,
1308                                       NULL, target, GLOBAL_ROOT_UID, info,
1309                                       error);
1310
1311         return error;
1312 }
1313
1314 static const char *stack_msg = "change_profile unprivileged unconfined converted to stacking";
1315
1316 /**
1317  * aa_change_profile - perform a one-way profile transition
1318  * @fqname: name of profile may include namespace (NOT NULL)
1319  * @flags: flags affecting change behavior
1320  *
1321  * Change to new profile @name.  Unlike with hats, there is no way
1322  * to change back.  If @name isn't specified the current profile name is
1323  * used.
1324  * If @onexec then the transition is delayed until
1325  * the next exec.
1326  *
1327  * Returns %0 on success, error otherwise.
1328  */
1329 int aa_change_profile(const char *fqname, int flags)
1330 {
1331         struct aa_label *label, *new = NULL, *target = NULL;
1332         struct aa_profile *profile;
1333         struct aa_perms perms = {};
1334         const char *info = NULL;
1335         const char *auditname = fqname;         /* retain leading & if stack */
1336         bool stack = flags & AA_CHANGE_STACK;
1337         struct aa_task_ctx *ctx = task_ctx(current);
1338         const struct cred *subj_cred = get_current_cred();
1339         int error = 0;
1340         char *op;
1341         u32 request;
1342
1343         label = aa_get_current_label();
1344
1345         /*
1346          * Detect no new privs being set, and store the label it
1347          * occurred under. Ideally this would happen when nnp
1348          * is set but there isn't a good way to do that yet.
1349          *
1350          * Testing for unconfined must be done before the subset test
1351          */
1352         if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
1353                 ctx->nnp = aa_get_label(label);
1354
1355         if (!fqname || !*fqname) {
1356                 aa_put_label(label);
1357                 AA_DEBUG("no profile name");
1358                 return -EINVAL;
1359         }
1360
1361         if (flags & AA_CHANGE_ONEXEC) {
1362                 request = AA_MAY_ONEXEC;
1363                 if (stack)
1364                         op = OP_STACK_ONEXEC;
1365                 else
1366                         op = OP_CHANGE_ONEXEC;
1367         } else {
1368                 request = AA_MAY_CHANGE_PROFILE;
1369                 if (stack)
1370                         op = OP_STACK;
1371                 else
1372                         op = OP_CHANGE_PROFILE;
1373         }
1374
1375         /* This should move to a per profile test. Requires pushing build
1376          * into callback
1377          */
1378         if (!stack && unconfined(label) &&
1379             label == &labels_ns(label)->unconfined->label &&
1380             aa_unprivileged_unconfined_restricted &&
1381             /* TODO: refactor so this check is a fn */
1382             cap_capable(current_cred(), &init_user_ns, CAP_MAC_OVERRIDE,
1383                         CAP_OPT_NOAUDIT)) {
1384                 /* regardless of the request in this case apparmor
1385                  * stacks against unconfined so admin set policy can't be
1386                  * by-passed
1387                  */
1388                 stack = true;
1389                 perms.audit = request;
1390                 (void) fn_for_each_in_ns(label, profile,
1391                                 aa_audit_file(subj_cred, profile, &perms, op,
1392                                               request, auditname, NULL, target,
1393                                               GLOBAL_ROOT_UID, stack_msg, 0));
1394                 perms.audit = 0;
1395         }
1396
1397         if (*fqname == '&') {
1398                 stack = true;
1399                 /* don't have label_parse() do stacking */
1400                 fqname++;
1401         }
1402         target = aa_label_parse(label, fqname, GFP_KERNEL, true, false);
1403         if (IS_ERR(target)) {
1404                 struct aa_profile *tprofile;
1405
1406                 info = "label not found";
1407                 error = PTR_ERR(target);
1408                 target = NULL;
1409                 /*
1410                  * TODO: fixme using labels_profile is not right - do profile
1411                  * per complain profile
1412                  */
1413                 if ((flags & AA_CHANGE_TEST) ||
1414                     !COMPLAIN_MODE(labels_profile(label)))
1415                         goto audit;
1416                 /* released below */
1417                 tprofile = aa_new_learning_profile(labels_profile(label), false,
1418                                                    fqname, GFP_KERNEL);
1419                 if (!tprofile) {
1420                         info = "failed null profile create";
1421                         error = -ENOMEM;
1422                         goto audit;
1423                 }
1424                 target = &tprofile->label;
1425                 goto check;
1426         }
1427
1428         /*
1429          * self directed transitions only apply to current policy ns
1430          * TODO: currently requiring perms for stacking and straight change
1431          *       stacking doesn't strictly need this. Determine how much
1432          *       we want to loosen this restriction for stacking
1433          *
1434          * if (!stack) {
1435          */
1436         error = fn_for_each_in_ns(label, profile,
1437                         change_profile_perms_wrapper(op, auditname,
1438                                                      subj_cred,
1439                                                      profile, target, stack,
1440                                                      request, &perms));
1441         if (error)
1442                 /* auditing done in change_profile_perms_wrapper */
1443                 goto out;
1444
1445         /* } */
1446
1447 check:
1448         /* check if tracing task is allowed to trace target domain */
1449         error = may_change_ptraced_domain(subj_cred, target, &info);
1450         if (error && !fn_for_each_in_ns(label, profile,
1451                                         COMPLAIN_MODE(profile)))
1452                 goto audit;
1453
1454         /* TODO: add permission check to allow this
1455          * if ((flags & AA_CHANGE_ONEXEC) && !current_is_single_threaded()) {
1456          *      info = "not a single threaded task";
1457          *      error = -EACCES;
1458          *      goto audit;
1459          * }
1460          */
1461         if (flags & AA_CHANGE_TEST)
1462                 goto out;
1463
1464         /* stacking is always a subset, so only check the nonstack case */
1465         if (!stack) {
1466                 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
1467                                            aa_get_label(target),
1468                                            aa_get_label(&profile->label));
1469                 /*
1470                  * no new privs prevents domain transitions that would
1471                  * reduce restrictions.
1472                  */
1473                 if (task_no_new_privs(current) && !unconfined(label) &&
1474                     !aa_label_is_unconfined_subset(new, ctx->nnp)) {
1475                         /* not an apparmor denial per se, so don't log it */
1476                         AA_DEBUG("no_new_privs - change_hat denied");
1477                         error = -EPERM;
1478                         goto out;
1479                 }
1480         }
1481
1482         if (!(flags & AA_CHANGE_ONEXEC)) {
1483                 /* only transition profiles in the current ns */
1484                 if (stack)
1485                         new = aa_label_merge(label, target, GFP_KERNEL);
1486                 if (IS_ERR_OR_NULL(new)) {
1487                         info = "failed to build target label";
1488                         if (!new)
1489                                 error = -ENOMEM;
1490                         else
1491                                 error = PTR_ERR(new);
1492                         new = NULL;
1493                         perms.allow = 0;
1494                         goto audit;
1495                 }
1496                 error = aa_replace_current_label(new);
1497         } else {
1498                 if (new) {
1499                         aa_put_label(new);
1500                         new = NULL;
1501                 }
1502
1503                 /* full transition will be built in exec path */
1504                 aa_set_current_onexec(target, stack);
1505         }
1506
1507 audit:
1508         error = fn_for_each_in_ns(label, profile,
1509                         aa_audit_file(subj_cred,
1510                                       profile, &perms, op, request, auditname,
1511                                       NULL, new ? new : target,
1512                                       GLOBAL_ROOT_UID, info, error));
1513
1514 out:
1515         aa_put_label(new);
1516         aa_put_label(target);
1517         aa_put_label(label);
1518         put_cred(subj_cred);
1519
1520         return error;
1521 }