fs/proc/base.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/fs/proc/base.c
   4  *
   5  *  Copyright (C) 1991, 1992 Linus Torvalds
   6  *
   7  *  proc base directory handling functions
   8  *
   9  *  1999, Al Viro. Rewritten. Now it covers the whole per-process part.
  10  *  Instead of using magical inumbers to determine the kind of object
  11  *  we allocate and fill in-core inodes upon lookup. They don't even
  12  *  go into icache. We cache the reference to task_struct upon lookup too.
  13  *  Eventually it should become a filesystem in its own. We don't use the
  14  *  rest of procfs anymore.
  15  *
  16  *
  17  *  Changelog:
  18  *  17-Jan-2005
  19  *  Allan Bezerra
  20  *  Bruna Moreira <bruna.moreira@indt.org.br>
  21  *  Edjard Mota <edjard.mota@indt.org.br>
  22  *  Ilias Biris <ilias.biris@indt.org.br>
  23  *  Mauricio Lin <mauricio.lin@indt.org.br>
  24  *
  25  *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
  26  *
  27  *  A new process specific entry (smaps) included in /proc. It shows the
  28  *  size of rss for each memory area. The maps entry lacks information
  29  *  about physical memory size (rss) for each mapped file, i.e.,
  30  *  rss information for executables and library files.
  31  *  This additional information is useful for any tools that need to know
  32  *  about physical memory consumption for a process specific library.
  33  *
  34  *  Changelog:
  35  *  21-Feb-2005
  36  *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
  37  *  Pud inclusion in the page table walking.
  38  *
  39  *  ChangeLog:
  40  *  10-Mar-2005
  41  *  10LE Instituto Nokia de Tecnologia - INdT:
  42  *  A better way to walks through the page table as suggested by Hugh Dickins.
  43  *
  44  *  Simo Piiroinen <simo.piiroinen@nokia.com>:
  45  *  Smaps information related to shared, private, clean and dirty pages.
  46  *
  47  *  Paul Mundt <paul.mundt@nokia.com>:
  48  *  Overall revision about smaps.
  49  */
  50
  51 #include <linux/uaccess.h>
  52
  53 #include <linux/errno.h>
  54 #include <linux/time.h>
  55 #include <linux/proc_fs.h>
  56 #include <linux/stat.h>
  57 #include <linux/task_io_accounting_ops.h>
  58 #include <linux/init.h>
  59 #include <linux/capability.h>
  60 #include <linux/file.h>
  61 #include <linux/fdtable.h>
  62 #include <linux/generic-radix-tree.h>
  63 #include <linux/string.h>
  64 #include <linux/seq_file.h>
  65 #include <linux/namei.h>
  66 #include <linux/mnt_namespace.h>
  67 #include <linux/mm.h>
  68 #include <linux/swap.h>
  69 #include <linux/rcupdate.h>
  70 #include <linux/kallsyms.h>
  71 #include <linux/stacktrace.h>
  72 #include <linux/resource.h>
  73 #include <linux/module.h>
  74 #include <linux/mount.h>
  75 #include <linux/security.h>
  76 #include <linux/ptrace.h>
  77 #include <linux/printk.h>
  78 #include <linux/cache.h>
  79 #include <linux/cgroup.h>
  80 #include <linux/cpuset.h>
  81 #include <linux/audit.h>
  82 #include <linux/poll.h>
  83 #include <linux/nsproxy.h>
  84 #include <linux/oom.h>
  85 #include <linux/elf.h>
  86 #include <linux/pid_namespace.h>
  87 #include <linux/user_namespace.h>
  88 #include <linux/fs_struct.h>
  89 #include <linux/slab.h>
  90 #include <linux/sched/autogroup.h>
  91 #include <linux/sched/mm.h>
  92 #include <linux/sched/coredump.h>
  93 #include <linux/sched/debug.h>
  94 #include <linux/sched/stat.h>
  95 #include <linux/posix-timers.h>
  96 #include <linux/time_namespace.h>
  97 #include <linux/resctrl.h>
  98 #include <linux/cn_proc.h>
  99 #include <trace/events/oom.h>
 100 #include "internal.h"
 101 #include "fd.h"
 102
 103 #include "../../lib/kstrtox.h"
 104
 105 /* NOTE:
 106  *      Implementing inode permission operations in /proc is almost
 107  *      certainly an error.  Permission checks need to happen during
 108  *      each system call not at open time.  The reason is that most of
 109  *      what we wish to check for permissions in /proc varies at runtime.
 110  *
 111  *      The classic example of a problem is opening file descriptors
 112  *      in /proc for a task before it execs a suid executable.
 113  */
 114
 115 static u8 nlink_tid __ro_after_init;
 116 static u8 nlink_tgid __ro_after_init;
 117
 118 struct pid_entry {
 119         const char *name;
 120         unsigned int len;
 121         umode_t mode;
 122         const struct inode_operations *iop;
 123         const struct file_operations *fop;
 124         union proc_op op;
 125 };
 126
 127 #define NOD(NAME, MODE, IOP, FOP, OP) {                 \
 128         .name = (NAME),                                 \
 129         .len  = sizeof(NAME) - 1,                       \
 130         .mode = MODE,                                   \
 131         .iop  = IOP,                                    \
 132         .fop  = FOP,                                    \
 133         .op   = OP,                                     \
 134 }
 135
 136 #define DIR(NAME, MODE, iops, fops)     \
 137         NOD(NAME, (S_IFDIR|(MODE)), &iops, &fops, {} )
 138 #define LNK(NAME, get_link)                                     \
 139         NOD(NAME, (S_IFLNK|S_IRWXUGO),                          \
 140                 &proc_pid_link_inode_operations, NULL,          \
 141                 { .proc_get_link = get_link } )
 142 #define REG(NAME, MODE, fops)                           \
 143         NOD(NAME, (S_IFREG|(MODE)), NULL, &fops, {})
 144 #define ONE(NAME, MODE, show)                           \
 145         NOD(NAME, (S_IFREG|(MODE)),                     \
 146                 NULL, &proc_single_file_operations,     \
 147                 { .proc_show = show } )
 148 #define ATTR(LSM, NAME, MODE)                           \
 149         NOD(NAME, (S_IFREG|(MODE)),                     \
 150                 NULL, &proc_pid_attr_operations,        \
 151                 { .lsm = LSM })
 152
 153 /*
 154  * Count the number of hardlinks for the pid_entry table, excluding the .
 155  * and .. links.
 156  */
 157 static unsigned int __init pid_entry_nlink(const struct pid_entry *entries,
 158         unsigned int n)
 159 {
 160         unsigned int i;
 161         unsigned int count;
 162
 163         count = 2;
 164         for (i = 0; i < n; ++i) {
 165                 if (S_ISDIR(entries[i].mode))
 166                         ++count;
 167         }
 168
 169         return count;
 170 }
 171
 172 static int get_task_root(struct task_struct *task, struct path *root)
 173 {
 174         int result = -ENOENT;
 175
 176         task_lock(task);
 177         if (task->fs) {
 178                 get_fs_root(task->fs, root);
 179                 result = 0;
 180         }
 181         task_unlock(task);
 182         return result;
 183 }
 184
 185 static int proc_cwd_link(struct dentry *dentry, struct path *path)
 186 {
 187         struct task_struct *task = get_proc_task(d_inode(dentry));
 188         int result = -ENOENT;
 189
 190         if (task) {
 191                 task_lock(task);
 192                 if (task->fs) {
 193                         get_fs_pwd(task->fs, path);
 194                         result = 0;
 195                 }
 196                 task_unlock(task);
 197                 put_task_struct(task);
 198         }
 199         return result;
 200 }
 201
 202 static int proc_root_link(struct dentry *dentry, struct path *path)
 203 {
 204         struct task_struct *task = get_proc_task(d_inode(dentry));
 205         int result = -ENOENT;
 206
 207         if (task) {
 208                 result = get_task_root(task, path);
 209                 put_task_struct(task);
 210         }
 211         return result;
 212 }
 213
 214 /*
 215  * If the user used setproctitle(), we just get the string from
 216  * user space at arg_start, and limit it to a maximum of one page.
 217  */
 218 static ssize_t get_mm_proctitle(struct mm_struct *mm, char __user *buf,
 219                                 size_t count, unsigned long pos,
 220                                 unsigned long arg_start)
 221 {
 222         char *page;
 223         int ret, got;
 224
 225         if (pos >= PAGE_SIZE)
 226                 return 0;
 227
 228         page = (char *)__get_free_page(GFP_KERNEL);
 229         if (!page)
 230                 return -ENOMEM;
 231
 232         ret = 0;
 233         got = access_remote_vm(mm, arg_start, page, PAGE_SIZE, FOLL_ANON);
 234         if (got > 0) {
 235                 int len = strnlen(page, got);
 236
 237                 /* Include the NUL character if it was found */
 238                 if (len < got)
 239                         len++;
 240
 241                 if (len > pos) {
 242                         len -= pos;
 243                         if (len > count)
 244                                 len = count;
 245                         len -= copy_to_user(buf, page+pos, len);
 246                         if (!len)
 247                                 len = -EFAULT;
 248                         ret = len;
 249                 }
 250         }
 251         free_page((unsigned long)page);
 252         return ret;
 253 }
 254
 255 static ssize_t get_mm_cmdline(struct mm_struct *mm, char __user *buf,
 256                               size_t count, loff_t *ppos)
 257 {
 258         unsigned long arg_start, arg_end, env_start, env_end;
 259         unsigned long pos, len;
 260         char *page, c;
 261
 262         /* Check if process spawned far enough to have cmdline. */
 263         if (!mm->env_end)
 264                 return 0;
 265
 266         spin_lock(&mm->arg_lock);
 267         arg_start = mm->arg_start;
 268         arg_end = mm->arg_end;
 269         env_start = mm->env_start;
 270         env_end = mm->env_end;
 271         spin_unlock(&mm->arg_lock);
 272
 273         if (arg_start >= arg_end)
 274                 return 0;
 275
 276         /*
 277          * We allow setproctitle() to overwrite the argument
 278          * strings, and overflow past the original end. But
 279          * only when it overflows into the environment area.
 280          */
 281         if (env_start != arg_end || env_end < env_start)
 282                 env_start = env_end = arg_end;
 283         len = env_end - arg_start;
 284
 285         /* We're not going to care if "*ppos" has high bits set */
 286         pos = *ppos;
 287         if (pos >= len)
 288                 return 0;
 289         if (count > len - pos)
 290                 count = len - pos;
 291         if (!count)
 292                 return 0;
 293
 294         /*
 295          * Magical special case: if the argv[] end byte is not
 296          * zero, the user has overwritten it with setproctitle(3).
 297          *
 298          * Possible future enhancement: do this only once when
 299          * pos is 0, and set a flag in the 'struct file'.
 300          */
 301         if (access_remote_vm(mm, arg_end-1, &c, 1, FOLL_ANON) == 1 && c)
 302                 return get_mm_proctitle(mm, buf, count, pos, arg_start);
 303
 304         /*
 305          * For the non-setproctitle() case we limit things strictly
 306          * to the [arg_start, arg_end[ range.
 307          */
 308         pos += arg_start;
 309         if (pos < arg_start || pos >= arg_end)
 310                 return 0;
 311         if (count > arg_end - pos)
 312                 count = arg_end - pos;
 313
 314         page = (char *)__get_free_page(GFP_KERNEL);
 315         if (!page)
 316                 return -ENOMEM;
 317
 318         len = 0;
 319         while (count) {
 320                 int got;
 321                 size_t size = min_t(size_t, PAGE_SIZE, count);
 322
 323                 got = access_remote_vm(mm, pos, page, size, FOLL_ANON);
 324                 if (got <= 0)
 325                         break;
 326                 got -= copy_to_user(buf, page, got);
 327                 if (unlikely(!got)) {
 328                         if (!len)
 329                                 len = -EFAULT;
 330                         break;
 331                 }
 332                 pos += got;
 333                 buf += got;
 334                 len += got;
 335                 count -= got;
 336         }
 337
 338         free_page((unsigned long)page);
 339         return len;
 340 }
 341
 342 static ssize_t get_task_cmdline(struct task_struct *tsk, char __user *buf,
 343                                 size_t count, loff_t *pos)
 344 {
 345         struct mm_struct *mm;
 346         ssize_t ret;
 347
 348         mm = get_task_mm(tsk);
 349         if (!mm)
 350                 return 0;
 351
 352         ret = get_mm_cmdline(mm, buf, count, pos);
 353         mmput(mm);
 354         return ret;
 355 }
 356
 357 static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
 358                                      size_t count, loff_t *pos)
 359 {
 360         struct task_struct *tsk;
 361         ssize_t ret;
 362
 363         BUG_ON(*pos < 0);
 364
 365         tsk = get_proc_task(file_inode(file));
 366         if (!tsk)
 367                 return -ESRCH;
 368         ret = get_task_cmdline(tsk, buf, count, pos);
 369         put_task_struct(tsk);
 370         if (ret > 0)
 371                 *pos += ret;
 372         return ret;
 373 }
 374
 375 static const struct file_operations proc_pid_cmdline_ops = {
 376         .read   = proc_pid_cmdline_read,
 377         .llseek = generic_file_llseek,
 378 };
 379
 380 #ifdef CONFIG_KALLSYMS
 381 /*
 382  * Provides a wchan file via kallsyms in a proper one-value-per-file format.
 383  * Returns the resolved symbol.  If that fails, simply return the address.
 384  */
 385 static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns,
 386                           struct pid *pid, struct task_struct *task)
 387 {
 388         unsigned long wchan;
 389         char symname[KSYM_NAME_LEN];
 390
 391         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
 392                 goto print0;
 393
 394         wchan = get_wchan(task);
 395         if (wchan && !lookup_symbol_name(wchan, symname)) {
 396                 seq_puts(m, symname);
 397                 return 0;
 398         }
 399
 400 print0:
 401         seq_putc(m, '0');
 402         return 0;
 403 }
 404 #endif /* CONFIG_KALLSYMS */
 405
 406 static int lock_trace(struct task_struct *task)
 407 {
 408         int err = down_read_killable(&task->signal->exec_update_lock);
 409         if (err)
 410                 return err;
 411         if (!ptrace_may_access(task, PTRACE_MODE_ATTACH_FSCREDS)) {
 412                 up_read(&task->signal->exec_update_lock);
 413                 return -EPERM;
 414         }
 415         return 0;
 416 }
 417
 418 static void unlock_trace(struct task_struct *task)
 419 {
 420         up_read(&task->signal->exec_update_lock);
 421 }
 422
 423 #ifdef CONFIG_STACKTRACE
 424
 425 #define MAX_STACK_TRACE_DEPTH   64
 426
 427 static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
 428                           struct pid *pid, struct task_struct *task)
 429 {
 430         unsigned long *entries;
 431         int err;
 432
 433         /*
 434          * The ability to racily run the kernel stack unwinder on a running task
 435          * and then observe the unwinder output is scary; while it is useful for
 436          * debugging kernel issues, it can also allow an attacker to leak kernel
 437          * stack contents.
 438          * Doing this in a manner that is at least safe from races would require
 439          * some work to ensure that the remote task can not be scheduled; and
 440          * even then, this would still expose the unwinder as local attack
 441          * surface.
 442          * Therefore, this interface is restricted to root.
 443          */
 444         if (!file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN))
 445                 return -EACCES;
 446
 447         entries = kmalloc_array(MAX_STACK_TRACE_DEPTH, sizeof(*entries),
 448                                 GFP_KERNEL);
 449         if (!entries)
 450                 return -ENOMEM;
 451
 452         err = lock_trace(task);
 453         if (!err) {
 454                 unsigned int i, nr_entries;
 455
 456                 nr_entries = stack_trace_save_tsk(task, entries,
 457                                                   MAX_STACK_TRACE_DEPTH, 0);
 458
 459                 for (i = 0; i < nr_entries; i++) {
 460                         seq_printf(m, "[<0>] %pB\n", (void *)entries[i]);
 461                 }
 462
 463                 unlock_trace(task);
 464         }
 465         kfree(entries);
 466
 467         return err;
 468 }
 469 #endif
 470
 471 #ifdef CONFIG_SCHED_INFO
 472 /*
 473  * Provides /proc/PID/schedstat
 474  */
 475 static int proc_pid_schedstat(struct seq_file *m, struct pid_namespace *ns,
 476                               struct pid *pid, struct task_struct *task)
 477 {
 478         if (unlikely(!sched_info_on()))
 479                 seq_puts(m, "0 0 0\n");
 480         else
 481                 seq_printf(m, "%llu %llu %lu\n",
 482                    (unsigned long long)task->se.sum_exec_runtime,
 483                    (unsigned long long)task->sched_info.run_delay,
 484                    task->sched_info.pcount);
 485
 486         return 0;
 487 }
 488 #endif
 489
 490 #ifdef CONFIG_LATENCYTOP
 491 static int lstats_show_proc(struct seq_file *m, void *v)
 492 {
 493         int i;
 494         struct inode *inode = m->private;
 495         struct task_struct *task = get_proc_task(inode);
 496
 497         if (!task)
 498                 return -ESRCH;
 499         seq_puts(m, "Latency Top version : v0.1\n");
 500         for (i = 0; i < LT_SAVECOUNT; i++) {
 501                 struct latency_record *lr = &task->latency_record[i];
 502                 if (lr->backtrace[0]) {
 503                         int q;
 504                         seq_printf(m, "%i %li %li",
 505                                    lr->count, lr->time, lr->max);
 506                         for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
 507                                 unsigned long bt = lr->backtrace[q];
 508
 509                                 if (!bt)
 510                                         break;
 511                                 seq_printf(m, " %ps", (void *)bt);
 512                         }
 513                         seq_putc(m, '\n');
 514                 }
 515
 516         }
 517         put_task_struct(task);
 518         return 0;
 519 }
 520
 521 static int lstats_open(struct inode *inode, struct file *file)
 522 {
 523         return single_open(file, lstats_show_proc, inode);
 524 }
 525
 526 static ssize_t lstats_write(struct file *file, const char __user *buf,
 527                             size_t count, loff_t *offs)
 528 {
 529         struct task_struct *task = get_proc_task(file_inode(file));
 530
 531         if (!task)
 532                 return -ESRCH;
 533         clear_tsk_latency_tracing(task);
 534         put_task_struct(task);
 535
 536         return count;
 537 }
 538
 539 static const struct file_operations proc_lstats_operations = {
 540         .open           = lstats_open,
 541         .read           = seq_read,
 542         .write          = lstats_write,
 543         .llseek         = seq_lseek,
 544         .release        = single_release,
 545 };
 546
 547 #endif
 548
 549 static int proc_oom_score(struct seq_file *m, struct pid_namespace *ns,
 550                           struct pid *pid, struct task_struct *task)
 551 {
 552         unsigned long totalpages = totalram_pages() + total_swap_pages;
 553         unsigned long points = 0;
 554         long badness;
 555
 556         badness = oom_badness(task, totalpages);
 557         /*
 558          * Special case OOM_SCORE_ADJ_MIN for all others scale the
 559          * badness value into [0, 2000] range which we have been
 560          * exporting for a long time so userspace might depend on it.
 561          */
 562         if (badness != LONG_MIN)
 563                 points = (1000 + badness * 1000 / (long)totalpages) * 2 / 3;
 564
 565         seq_printf(m, "%lu\n", points);
 566
 567         return 0;
 568 }
 569
 570 struct limit_names {
 571         const char *name;
 572         const char *unit;
 573 };
 574
 575 static const struct limit_names lnames[RLIM_NLIMITS] = {
 576         [RLIMIT_CPU] = {"Max cpu time", "seconds"},
 577         [RLIMIT_FSIZE] = {"Max file size", "bytes"},
 578         [RLIMIT_DATA] = {"Max data size", "bytes"},
 579         [RLIMIT_STACK] = {"Max stack size", "bytes"},
 580         [RLIMIT_CORE] = {"Max core file size", "bytes"},
 581         [RLIMIT_RSS] = {"Max resident set", "bytes"},
 582         [RLIMIT_NPROC] = {"Max processes", "processes"},
 583         [RLIMIT_NOFILE] = {"Max open files", "files"},
 584         [RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
 585         [RLIMIT_AS] = {"Max address space", "bytes"},
 586         [RLIMIT_LOCKS] = {"Max file locks", "locks"},
 587         [RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
 588         [RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
 589         [RLIMIT_NICE] = {"Max nice priority", NULL},
 590         [RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
 591         [RLIMIT_RTTIME] = {"Max realtime timeout", "us"},
 592 };
 593
 594 /* Display limits for a process */
 595 static int proc_pid_limits(struct seq_file *m, struct pid_namespace *ns,
 596                            struct pid *pid, struct task_struct *task)
 597 {
 598         unsigned int i;
 599         unsigned long flags;
 600
 601         struct rlimit rlim[RLIM_NLIMITS];
 602
 603         if (!lock_task_sighand(task, &flags))
 604                 return 0;
 605         memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
 606         unlock_task_sighand(task, &flags);
 607
 608         /*
 609          * print the file header
 610          */
 611         seq_puts(m, "Limit                     "
 612                 "Soft Limit           "
 613                 "Hard Limit           "
 614                 "Units     \n");
 615
 616         for (i = 0; i < RLIM_NLIMITS; i++) {
 617                 if (rlim[i].rlim_cur == RLIM_INFINITY)
 618                         seq_printf(m, "%-25s %-20s ",
 619                                    lnames[i].name, "unlimited");
 620                 else
 621                         seq_printf(m, "%-25s %-20lu ",
 622                                    lnames[i].name, rlim[i].rlim_cur);
 623
 624                 if (rlim[i].rlim_max == RLIM_INFINITY)
 625                         seq_printf(m, "%-20s ", "unlimited");
 626                 else
 627                         seq_printf(m, "%-20lu ", rlim[i].rlim_max);
 628
 629                 if (lnames[i].unit)
 630                         seq_printf(m, "%-10s\n", lnames[i].unit);
 631                 else
 632                         seq_putc(m, '\n');
 633         }
 634
 635         return 0;
 636 }
 637
 638 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
 639 static int proc_pid_syscall(struct seq_file *m, struct pid_namespace *ns,
 640                             struct pid *pid, struct task_struct *task)
 641 {
 642         struct syscall_info info;
 643         u64 *args = &info.data.args[0];
 644         int res;
 645
 646         res = lock_trace(task);
 647         if (res)
 648                 return res;
 649
 650         if (task_current_syscall(task, &info))
 651                 seq_puts(m, "running\n");
 652         else if (info.data.nr < 0)
 653                 seq_printf(m, "%d 0x%llx 0x%llx\n",
 654                            info.data.nr, info.sp, info.data.instruction_pointer);
 655         else
 656                 seq_printf(m,
 657                        "%d 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx\n",
 658                        info.data.nr,
 659                        args[0], args[1], args[2], args[3], args[4], args[5],
 660                        info.sp, info.data.instruction_pointer);
 661         unlock_trace(task);
 662
 663         return 0;
 664 }
 665 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
 666
 667 /************************************************************************/
 668 /*                       Here the fs part begins                        */
 669 /************************************************************************/
 670
 671 /* permission checks */
 672 static bool proc_fd_access_allowed(struct inode *inode)
 673 {
 674         struct task_struct *task;
 675         bool allowed = false;
 676         /* Allow access to a task's file descriptors if it is us or we
 677          * may use ptrace attach to the process and find out that
 678          * information.
 679          */
 680         task = get_proc_task(inode);
 681         if (task) {
 682                 allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 683                 put_task_struct(task);
 684         }
 685         return allowed;
 686 }
 687
 688 int proc_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
 689                  struct iattr *attr)
 690 {
 691         int error;
 692         struct inode *inode = d_inode(dentry);
 693
 694         if (attr->ia_valid & ATTR_MODE)
 695                 return -EPERM;
 696
 697         error = setattr_prepare(&init_user_ns, dentry, attr);
 698         if (error)
 699                 return error;
 700
 701         setattr_copy(&init_user_ns, inode, attr);
 702         mark_inode_dirty(inode);
 703         return 0;
 704 }
 705
 706 /*
 707  * May current process learn task's sched/cmdline info (for hide_pid_min=1)
 708  * or euid/egid (for hide_pid_min=2)?
 709  */
 710 static bool has_pid_permissions(struct proc_fs_info *fs_info,
 711                                  struct task_struct *task,
 712                                  enum proc_hidepid hide_pid_min)
 713 {
 714         /*
 715          * If 'hidpid' mount option is set force a ptrace check,
 716          * we indicate that we are using a filesystem syscall
 717          * by passing PTRACE_MODE_READ_FSCREDS
 718          */
 719         if (fs_info->hide_pid == HIDEPID_NOT_PTRACEABLE)
 720                 return ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 721
 722         if (fs_info->hide_pid < hide_pid_min)
 723                 return true;
 724         if (in_group_p(fs_info->pid_gid))
 725                 return true;
 726         return ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 727 }
 728
 729
 730 static int proc_pid_permission(struct user_namespace *mnt_userns,
 731                                struct inode *inode, int mask)
 732 {
 733         struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb);
 734         struct task_struct *task;
 735         bool has_perms;
 736
 737         task = get_proc_task(inode);
 738         if (!task)
 739                 return -ESRCH;
 740         has_perms = has_pid_permissions(fs_info, task, HIDEPID_NO_ACCESS);
 741         put_task_struct(task);
 742
 743         if (!has_perms) {
 744                 if (fs_info->hide_pid == HIDEPID_INVISIBLE) {
 745                         /*
 746                          * Let's make getdents(), stat(), and open()
 747                          * consistent with each other.  If a process
 748                          * may not stat() a file, it shouldn't be seen
 749                          * in procfs at all.
 750                          */
 751                         return -ENOENT;
 752                 }
 753
 754                 return -EPERM;
 755         }
 756         return generic_permission(&init_user_ns, inode, mask);
 757 }
 758
 759
 760
 761 static const struct inode_operations proc_def_inode_operations = {
 762         .setattr        = proc_setattr,
 763 };
 764
 765 static int proc_single_show(struct seq_file *m, void *v)
 766 {
 767         struct inode *inode = m->private;
 768         struct pid_namespace *ns = proc_pid_ns(inode->i_sb);
 769         struct pid *pid = proc_pid(inode);
 770         struct task_struct *task;
 771         int ret;
 772
 773         task = get_pid_task(pid, PIDTYPE_PID);
 774         if (!task)
 775                 return -ESRCH;
 776
 777         ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);
 778
 779         put_task_struct(task);
 780         return ret;
 781 }
 782
 783 static int proc_single_open(struct inode *inode, struct file *filp)
 784 {
 785         return single_open(filp, proc_single_show, inode);
 786 }
 787
 788 static const struct file_operations proc_single_file_operations = {
 789         .open           = proc_single_open,
 790         .read           = seq_read,
 791         .llseek         = seq_lseek,
 792         .release        = single_release,
 793 };
 794
 795
 796 struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode)
 797 {
 798         struct task_struct *task = get_proc_task(inode);
 799         struct mm_struct *mm = ERR_PTR(-ESRCH);
 800
 801         if (task) {
 802                 mm = mm_access(task, mode | PTRACE_MODE_FSCREDS);
 803                 put_task_struct(task);
 804
 805                 if (!IS_ERR_OR_NULL(mm)) {
 806                         /* ensure this mm_struct can't be freed */
 807                         mmgrab(mm);
 808                         /* but do not pin its memory */
 809                         mmput(mm);
 810                 }
 811         }
 812
 813         return mm;
 814 }
 815
 816 static int __mem_open(struct inode *inode, struct file *file, unsigned int mode)
 817 {
 818         struct mm_struct *mm = proc_mem_open(inode, mode);
 819
 820         if (IS_ERR(mm))
 821                 return PTR_ERR(mm);
 822
 823         file->private_data = mm;
 824         return 0;
 825 }
 826
 827 static int mem_open(struct inode *inode, struct file *file)
 828 {
 829         int ret = __mem_open(inode, file, PTRACE_MODE_ATTACH);
 830
 831         /* OK to pass negative loff_t, we can catch out-of-range */
 832         file->f_mode |= FMODE_UNSIGNED_OFFSET;
 833
 834         return ret;
 835 }
 836
 837 static ssize_t mem_rw(struct file *file, char __user *buf,
 838                         size_t count, loff_t *ppos, int write)
 839 {
 840         struct mm_struct *mm = file->private_data;
 841         unsigned long addr = *ppos;
 842         ssize_t copied;
 843         char *page;
 844         unsigned int flags;
 845
 846         if (!mm)
 847                 return 0;
 848
 849         page = (char *)__get_free_page(GFP_KERNEL);
 850         if (!page)
 851                 return -ENOMEM;
 852
 853         copied = 0;
 854         if (!mmget_not_zero(mm))
 855                 goto free;
 856
 857         flags = FOLL_FORCE | (write ? FOLL_WRITE : 0);
 858
 859         while (count > 0) {
 860                 size_t this_len = min_t(size_t, count, PAGE_SIZE);
 861
 862                 if (write && copy_from_user(page, buf, this_len)) {
 863                         copied = -EFAULT;
 864                         break;
 865                 }
 866
 867                 this_len = access_remote_vm(mm, addr, page, this_len, flags);
 868                 if (!this_len) {
 869                         if (!copied)
 870                                 copied = -EIO;
 871                         break;
 872                 }
 873
 874                 if (!write && copy_to_user(buf, page, this_len)) {
 875                         copied = -EFAULT;
 876                         break;
 877                 }
 878
 879                 buf += this_len;
 880                 addr += this_len;
 881                 copied += this_len;
 882                 count -= this_len;
 883         }
 884         *ppos = addr;
 885
 886         mmput(mm);
 887 free:
 888         free_page((unsigned long) page);
 889         return copied;
 890 }
 891
 892 static ssize_t mem_read(struct file *file, char __user *buf,
 893                         size_t count, loff_t *ppos)
 894 {
 895         return mem_rw(file, buf, count, ppos, 0);
 896 }
 897
 898 static ssize_t mem_write(struct file *file, const char __user *buf,
 899                          size_t count, loff_t *ppos)
 900 {
 901         return mem_rw(file, (char __user*)buf, count, ppos, 1);
 902 }
 903
 904 loff_t mem_lseek(struct file *file, loff_t offset, int orig)
 905 {
 906         switch (orig) {
 907         case 0:
 908                 file->f_pos = offset;
 909                 break;
 910         case 1:
 911                 file->f_pos += offset;
 912                 break;
 913         default:
 914                 return -EINVAL;
 915         }
 916         force_successful_syscall_return();
 917         return file->f_pos;
 918 }
 919
 920 static int mem_release(struct inode *inode, struct file *file)
 921 {
 922         struct mm_struct *mm = file->private_data;
 923         if (mm)
 924                 mmdrop(mm);
 925         return 0;
 926 }
 927
 928 static const struct file_operations proc_mem_operations = {
 929         .llseek         = mem_lseek,
 930         .read           = mem_read,
 931         .write          = mem_write,
 932         .open           = mem_open,
 933         .release        = mem_release,
 934 };
 935
 936 static int environ_open(struct inode *inode, struct file *file)
 937 {
 938         return __mem_open(inode, file, PTRACE_MODE_READ);
 939 }
 940
 941 static ssize_t environ_read(struct file *file, char __user *buf,
 942                         size_t count, loff_t *ppos)
 943 {
 944         char *page;
 945         unsigned long src = *ppos;
 946         int ret = 0;
 947         struct mm_struct *mm = file->private_data;
 948         unsigned long env_start, env_end;
 949
 950         /* Ensure the process spawned far enough to have an environment. */
 951         if (!mm || !mm->env_end)
 952                 return 0;
 953
 954         page = (char *)__get_free_page(GFP_KERNEL);
 955         if (!page)
 956                 return -ENOMEM;
 957
 958         ret = 0;
 959         if (!mmget_not_zero(mm))
 960                 goto free;
 961
 962         spin_lock(&mm->arg_lock);
 963         env_start = mm->env_start;
 964         env_end = mm->env_end;
 965         spin_unlock(&mm->arg_lock);
 966
 967         while (count > 0) {
 968                 size_t this_len, max_len;
 969                 int retval;
 970
 971                 if (src >= (env_end - env_start))
 972                         break;
 973
 974                 this_len = env_end - (env_start + src);
 975
 976                 max_len = min_t(size_t, PAGE_SIZE, count);
 977                 this_len = min(max_len, this_len);
 978
 979                 retval = access_remote_vm(mm, (env_start + src), page, this_len, FOLL_ANON);
 980
 981                 if (retval <= 0) {
 982                         ret = retval;
 983                         break;
 984                 }
 985
 986                 if (copy_to_user(buf, page, retval)) {
 987                         ret = -EFAULT;
 988                         break;
 989                 }
 990
 991                 ret += retval;
 992                 src += retval;
 993                 buf += retval;
 994                 count -= retval;
 995         }
 996         *ppos = src;
 997         mmput(mm);
 998
 999 free:
1000         free_page((unsigned long) page);
1001         return ret;
1002 }
1003
1004 static const struct file_operations proc_environ_operations = {
1005         .open           = environ_open,
1006         .read           = environ_read,
1007         .llseek         = generic_file_llseek,
1008         .release        = mem_release,
1009 };
1010
1011 static int auxv_open(struct inode *inode, struct file *file)
1012 {
1013         return __mem_open(inode, file, PTRACE_MODE_READ_FSCREDS);
1014 }
1015
1016 static ssize_t auxv_read(struct file *file, char __user *buf,
1017                         size_t count, loff_t *ppos)
1018 {
1019         struct mm_struct *mm = file->private_data;
1020         unsigned int nwords = 0;
1021
1022         if (!mm)
1023                 return 0;
1024         do {
1025                 nwords += 2;
1026         } while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
1027         return simple_read_from_buffer(buf, count, ppos, mm->saved_auxv,
1028                                        nwords * sizeof(mm->saved_auxv[0]));
1029 }
1030
1031 static const struct file_operations proc_auxv_operations = {
1032         .open           = auxv_open,
1033         .read           = auxv_read,
1034         .llseek         = generic_file_llseek,
1035         .release        = mem_release,
1036 };
1037
1038 static ssize_t oom_adj_read(struct file *file, char __user *buf, size_t count,
1039                             loff_t *ppos)
1040 {
1041         struct task_struct *task = get_proc_task(file_inode(file));
1042         char buffer[PROC_NUMBUF];
1043         int oom_adj = OOM_ADJUST_MIN;
1044         size_t len;
1045
1046         if (!task)
1047                 return -ESRCH;
1048         if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MAX)
1049                 oom_adj = OOM_ADJUST_MAX;
1050         else
1051                 oom_adj = (task->signal->oom_score_adj * -OOM_DISABLE) /
1052                           OOM_SCORE_ADJ_MAX;
1053         put_task_struct(task);
1054         if (oom_adj > OOM_ADJUST_MAX)
1055                 oom_adj = OOM_ADJUST_MAX;
1056         len = snprintf(buffer, sizeof(buffer), "%d\n", oom_adj);
1057         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1058 }
1059
1060 static int __set_oom_adj(struct file *file, int oom_adj, bool legacy)
1061 {
1062         struct mm_struct *mm = NULL;
1063         struct task_struct *task;
1064         int err = 0;
1065
1066         task = get_proc_task(file_inode(file));
1067         if (!task)
1068                 return -ESRCH;
1069
1070         mutex_lock(&oom_adj_mutex);
1071         if (legacy) {
1072                 if (oom_adj < task->signal->oom_score_adj &&
1073                                 !capable(CAP_SYS_RESOURCE)) {
1074                         err = -EACCES;
1075                         goto err_unlock;
1076                 }
1077                 /*
1078                  * /proc/pid/oom_adj is provided for legacy purposes, ask users to use
1079                  * /proc/pid/oom_score_adj instead.
1080                  */
1081                 pr_warn_once("%s (%d): /proc/%d/oom_adj is deprecated, please use /proc/%d/oom_score_adj instead.\n",
1082                           current->comm, task_pid_nr(current), task_pid_nr(task),
1083                           task_pid_nr(task));
1084         } else {
1085                 if ((short)oom_adj < task->signal->oom_score_adj_min &&
1086                                 !capable(CAP_SYS_RESOURCE)) {
1087                         err = -EACCES;
1088                         goto err_unlock;
1089                 }
1090         }
1091
1092         /*
1093          * Make sure we will check other processes sharing the mm if this is
1094          * not vfrok which wants its own oom_score_adj.
1095          * pin the mm so it doesn't go away and get reused after task_unlock
1096          */
1097         if (!task->vfork_done) {
1098                 struct task_struct *p = find_lock_task_mm(task);
1099
1100                 if (p) {
1101                         if (test_bit(MMF_MULTIPROCESS, &p->mm->flags)) {
1102                                 mm = p->mm;
1103                                 mmgrab(mm);
1104                         }
1105                         task_unlock(p);
1106                 }
1107         }
1108
1109         task->signal->oom_score_adj = oom_adj;
1110         if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
1111                 task->signal->oom_score_adj_min = (short)oom_adj;
1112         trace_oom_score_adj_update(task);
1113
1114         if (mm) {
1115                 struct task_struct *p;
1116
1117                 rcu_read_lock();
1118                 for_each_process(p) {
1119                         if (same_thread_group(task, p))
1120                                 continue;
1121
1122                         /* do not touch kernel threads or the global init */
1123                         if (p->flags & PF_KTHREAD || is_global_init(p))
1124                                 continue;
1125
1126                         task_lock(p);
1127                         if (!p->vfork_done && process_shares_mm(p, mm)) {
1128                                 p->signal->oom_score_adj = oom_adj;
1129                                 if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
1130                                         p->signal->oom_score_adj_min = (short)oom_adj;
1131                         }
1132                         task_unlock(p);
1133                 }
1134                 rcu_read_unlock();
1135                 mmdrop(mm);
1136         }
1137 err_unlock:
1138         mutex_unlock(&oom_adj_mutex);
1139         put_task_struct(task);
1140         return err;
1141 }
1142
1143 /*
1144  * /proc/pid/oom_adj exists solely for backwards compatibility with previous
1145  * kernels.  The effective policy is defined by oom_score_adj, which has a
1146  * different scale: oom_adj grew exponentially and oom_score_adj grows linearly.
1147  * Values written to oom_adj are simply mapped linearly to oom_score_adj.
1148  * Processes that become oom disabled via oom_adj will still be oom disabled
1149  * with this implementation.
1150  *
1151  * oom_adj cannot be removed since existing userspace binaries use it.
1152  */
1153 static ssize_t oom_adj_write(struct file *file, const char __user *buf,
1154                              size_t count, loff_t *ppos)
1155 {
1156         char buffer[PROC_NUMBUF];
1157         int oom_adj;
1158         int err;
1159
1160         memset(buffer, 0, sizeof(buffer));
1161         if (count > sizeof(buffer) - 1)
1162                 count = sizeof(buffer) - 1;
1163         if (copy_from_user(buffer, buf, count)) {
1164                 err = -EFAULT;
1165                 goto out;
1166         }
1167
1168         err = kstrtoint(strstrip(buffer), 0, &oom_adj);
1169         if (err)
1170                 goto out;
1171         if ((oom_adj < OOM_ADJUST_MIN || oom_adj > OOM_ADJUST_MAX) &&
1172              oom_adj != OOM_DISABLE) {
1173                 err = -EINVAL;
1174                 goto out;
1175         }
1176
1177         /*
1178          * Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
1179          * value is always attainable.
1180          */
1181         if (oom_adj == OOM_ADJUST_MAX)
1182                 oom_adj = OOM_SCORE_ADJ_MAX;
1183         else
1184                 oom_adj = (oom_adj * OOM_SCORE_ADJ_MAX) / -OOM_DISABLE;
1185
1186         err = __set_oom_adj(file, oom_adj, true);
1187 out:
1188         return err < 0 ? err : count;
1189 }
1190
1191 static const struct file_operations proc_oom_adj_operations = {
1192         .read           = oom_adj_read,
1193         .write          = oom_adj_write,
1194         .llseek         = generic_file_llseek,
1195 };
1196
1197 static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
1198                                         size_t count, loff_t *ppos)
1199 {
1200         struct task_struct *task = get_proc_task(file_inode(file));
1201         char buffer[PROC_NUMBUF];
1202         short oom_score_adj = OOM_SCORE_ADJ_MIN;
1203         size_t len;
1204
1205         if (!task)
1206                 return -ESRCH;
1207         oom_score_adj = task->signal->oom_score_adj;
1208         put_task_struct(task);
1209         len = snprintf(buffer, sizeof(buffer), "%hd\n", oom_score_adj);
1210         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1211 }
1212
1213 static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
1214                                         size_t count, loff_t *ppos)
1215 {
1216         char buffer[PROC_NUMBUF];
1217         int oom_score_adj;
1218         int err;
1219
1220         memset(buffer, 0, sizeof(buffer));
1221         if (count > sizeof(buffer) - 1)
1222                 count = sizeof(buffer) - 1;
1223         if (copy_from_user(buffer, buf, count)) {
1224                 err = -EFAULT;
1225                 goto out;
1226         }
1227
1228         err = kstrtoint(strstrip(buffer), 0, &oom_score_adj);
1229         if (err)
1230                 goto out;
1231         if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
1232                         oom_score_adj > OOM_SCORE_ADJ_MAX) {
1233                 err = -EINVAL;
1234                 goto out;
1235         }
1236
1237         err = __set_oom_adj(file, oom_score_adj, false);
1238 out:
1239         return err < 0 ? err : count;
1240 }
1241
1242 static const struct file_operations proc_oom_score_adj_operations = {
1243         .read           = oom_score_adj_read,
1244         .write          = oom_score_adj_write,
1245         .llseek         = default_llseek,
1246 };
1247
1248 #ifdef CONFIG_AUDIT
1249 #define TMPBUFLEN 11
1250 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
1251                                   size_t count, loff_t *ppos)
1252 {
1253         struct inode * inode = file_inode(file);
1254         struct task_struct *task = get_proc_task(inode);
1255         ssize_t length;
1256         char tmpbuf[TMPBUFLEN];
1257
1258         if (!task)
1259                 return -ESRCH;
1260         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1261                            from_kuid(file->f_cred->user_ns,
1262                                      audit_get_loginuid(task)));
1263         put_task_struct(task);
1264         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1265 }
1266
1267 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1268                                    size_t count, loff_t *ppos)
1269 {
1270         struct inode * inode = file_inode(file);
1271         uid_t loginuid;
1272         kuid_t kloginuid;
1273         int rv;
1274
1275         /* Don't let kthreads write their own loginuid */
1276         if (current->flags & PF_KTHREAD)
1277                 return -EPERM;
1278
1279         rcu_read_lock();
1280         if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
1281                 rcu_read_unlock();
1282                 return -EPERM;
1283         }
1284         rcu_read_unlock();
1285
1286         if (*ppos != 0) {
1287                 /* No partial writes. */
1288                 return -EINVAL;
1289         }
1290
1291         rv = kstrtou32_from_user(buf, count, 10, &loginuid);
1292         if (rv < 0)
1293                 return rv;
1294
1295         /* is userspace tring to explicitly UNSET the loginuid? */
1296         if (loginuid == AUDIT_UID_UNSET) {
1297                 kloginuid = INVALID_UID;
1298         } else {
1299                 kloginuid = make_kuid(file->f_cred->user_ns, loginuid);
1300                 if (!uid_valid(kloginuid))
1301                         return -EINVAL;
1302         }
1303
1304         rv = audit_set_loginuid(kloginuid);
1305         if (rv < 0)
1306                 return rv;
1307         return count;
1308 }
1309
1310 static const struct file_operations proc_loginuid_operations = {
1311         .read           = proc_loginuid_read,
1312         .write          = proc_loginuid_write,
1313         .llseek         = generic_file_llseek,
1314 };
1315
1316 static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
1317                                   size_t count, loff_t *ppos)
1318 {
1319         struct inode * inode = file_inode(file);
1320         struct task_struct *task = get_proc_task(inode);
1321         ssize_t length;
1322         char tmpbuf[TMPBUFLEN];
1323
1324         if (!task)
1325                 return -ESRCH;
1326         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1327                                 audit_get_sessionid(task));
1328         put_task_struct(task);
1329         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1330 }
1331
1332 static const struct file_operations proc_sessionid_operations = {
1333         .read           = proc_sessionid_read,
1334         .llseek         = generic_file_llseek,
1335 };
1336 #endif
1337
1338 #ifdef CONFIG_FAULT_INJECTION
1339 static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
1340                                       size_t count, loff_t *ppos)
1341 {
1342         struct task_struct *task = get_proc_task(file_inode(file));
1343         char buffer[PROC_NUMBUF];
1344         size_t len;
1345         int make_it_fail;
1346
1347         if (!task)
1348                 return -ESRCH;
1349         make_it_fail = task->make_it_fail;
1350         put_task_struct(task);
1351
1352         len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
1353
1354         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1355 }
1356
1357 static ssize_t proc_fault_inject_write(struct file * file,
1358                         const char __user * buf, size_t count, loff_t *ppos)
1359 {
1360         struct task_struct *task;
1361         char buffer[PROC_NUMBUF];
1362         int make_it_fail;
1363         int rv;
1364
1365         if (!capable(CAP_SYS_RESOURCE))
1366                 return -EPERM;
1367         memset(buffer, 0, sizeof(buffer));
1368         if (count > sizeof(buffer) - 1)
1369                 count = sizeof(buffer) - 1;
1370         if (copy_from_user(buffer, buf, count))
1371                 return -EFAULT;
1372         rv = kstrtoint(strstrip(buffer), 0, &make_it_fail);
1373         if (rv < 0)
1374                 return rv;
1375         if (make_it_fail < 0 || make_it_fail > 1)
1376                 return -EINVAL;
1377
1378         task = get_proc_task(file_inode(file));
1379         if (!task)
1380                 return -ESRCH;
1381         task->make_it_fail = make_it_fail;
1382         put_task_struct(task);
1383
1384         return count;
1385 }
1386
1387 static const struct file_operations proc_fault_inject_operations = {
1388         .read           = proc_fault_inject_read,
1389         .write          = proc_fault_inject_write,
1390         .llseek         = generic_file_llseek,
1391 };
1392
1393 static ssize_t proc_fail_nth_write(struct file *file, const char __user *buf,
1394                                    size_t count, loff_t *ppos)
1395 {
1396         struct task_struct *task;
1397         int err;
1398         unsigned int n;
1399
1400         err = kstrtouint_from_user(buf, count, 0, &n);
1401         if (err)
1402                 return err;
1403
1404         task = get_proc_task(file_inode(file));
1405         if (!task)
1406                 return -ESRCH;
1407         task->fail_nth = n;
1408         put_task_struct(task);
1409
1410         return count;
1411 }
1412
1413 static ssize_t proc_fail_nth_read(struct file *file, char __user *buf,
1414                                   size_t count, loff_t *ppos)
1415 {
1416         struct task_struct *task;
1417         char numbuf[PROC_NUMBUF];
1418         ssize_t len;
1419
1420         task = get_proc_task(file_inode(file));
1421         if (!task)
1422                 return -ESRCH;
1423         len = snprintf(numbuf, sizeof(numbuf), "%u\n", task->fail_nth);
1424         put_task_struct(task);
1425         return simple_read_from_buffer(buf, count, ppos, numbuf, len);
1426 }
1427
1428 static const struct file_operations proc_fail_nth_operations = {
1429         .read           = proc_fail_nth_read,
1430         .write          = proc_fail_nth_write,
1431 };
1432 #endif
1433
1434
1435 #ifdef CONFIG_SCHED_DEBUG
1436 /*
1437  * Print out various scheduling related per-task fields:
1438  */
1439 static int sched_show(struct seq_file *m, void *v)
1440 {
1441         struct inode *inode = m->private;
1442         struct pid_namespace *ns = proc_pid_ns(inode->i_sb);
1443         struct task_struct *p;
1444
1445         p = get_proc_task(inode);
1446         if (!p)
1447                 return -ESRCH;
1448         proc_sched_show_task(p, ns, m);
1449
1450         put_task_struct(p);
1451
1452         return 0;
1453 }
1454
1455 static ssize_t
1456 sched_write(struct file *file, const char __user *buf,
1457             size_t count, loff_t *offset)
1458 {
1459         struct inode *inode = file_inode(file);
1460         struct task_struct *p;
1461
1462         p = get_proc_task(inode);
1463         if (!p)
1464                 return -ESRCH;
1465         proc_sched_set_task(p);
1466
1467         put_task_struct(p);
1468
1469         return count;
1470 }
1471
1472 static int sched_open(struct inode *inode, struct file *filp)
1473 {
1474         return single_open(filp, sched_show, inode);
1475 }
1476
1477 static const struct file_operations proc_pid_sched_operations = {
1478         .open           = sched_open,
1479         .read           = seq_read,
1480         .write          = sched_write,
1481         .llseek         = seq_lseek,
1482         .release        = single_release,
1483 };
1484
1485 #endif
1486
1487 #ifdef CONFIG_SCHED_AUTOGROUP
1488 /*
1489  * Print out autogroup related information:
1490  */
1491 static int sched_autogroup_show(struct seq_file *m, void *v)
1492 {
1493         struct inode *inode = m->private;
1494         struct task_struct *p;
1495
1496         p = get_proc_task(inode);
1497         if (!p)
1498                 return -ESRCH;
1499         proc_sched_autogroup_show_task(p, m);
1500
1501         put_task_struct(p);
1502
1503         return 0;
1504 }
1505
1506 static ssize_t
1507 sched_autogroup_write(struct file *file, const char __user *buf,
1508             size_t count, loff_t *offset)
1509 {
1510         struct inode *inode = file_inode(file);
1511         struct task_struct *p;
1512         char buffer[PROC_NUMBUF];
1513         int nice;
1514         int err;
1515
1516         memset(buffer, 0, sizeof(buffer));
1517         if (count > sizeof(buffer) - 1)
1518                 count = sizeof(buffer) - 1;
1519         if (copy_from_user(buffer, buf, count))
1520                 return -EFAULT;
1521
1522         err = kstrtoint(strstrip(buffer), 0, &nice);
1523         if (err < 0)
1524                 return err;
1525
1526         p = get_proc_task(inode);
1527         if (!p)
1528                 return -ESRCH;
1529
1530         err = proc_sched_autogroup_set_nice(p, nice);
1531         if (err)
1532                 count = err;
1533
1534         put_task_struct(p);
1535
1536         return count;
1537 }
1538
1539 static int sched_autogroup_open(struct inode *inode, struct file *filp)
1540 {
1541         int ret;
1542
1543         ret = single_open(filp, sched_autogroup_show, NULL);
1544         if (!ret) {
1545                 struct seq_file *m = filp->private_data;
1546
1547                 m->private = inode;
1548         }
1549         return ret;
1550 }
1551
1552 static const struct file_operations proc_pid_sched_autogroup_operations = {
1553         .open           = sched_autogroup_open,
1554         .read           = seq_read,
1555         .write          = sched_autogroup_write,
1556         .llseek         = seq_lseek,
1557         .release        = single_release,
1558 };
1559
1560 #endif /* CONFIG_SCHED_AUTOGROUP */
1561
1562 #ifdef CONFIG_TIME_NS
1563 static int timens_offsets_show(struct seq_file *m, void *v)
1564 {
1565         struct task_struct *p;
1566
1567         p = get_proc_task(file_inode(m->file));
1568         if (!p)
1569                 return -ESRCH;
1570         proc_timens_show_offsets(p, m);
1571
1572         put_task_struct(p);
1573
1574         return 0;
1575 }
1576
1577 static ssize_t timens_offsets_write(struct file *file, const char __user *buf,
1578                                     size_t count, loff_t *ppos)
1579 {
1580         struct inode *inode = file_inode(file);
1581         struct proc_timens_offset offsets[2];
1582         char *kbuf = NULL, *pos, *next_line;
1583         struct task_struct *p;
1584         int ret, noffsets;
1585
1586         /* Only allow < page size writes at the beginning of the file */
1587         if ((*ppos != 0) || (count >= PAGE_SIZE))
1588                 return -EINVAL;
1589
1590         /* Slurp in the user data */
1591         kbuf = memdup_user_nul(buf, count);
1592         if (IS_ERR(kbuf))
1593                 return PTR_ERR(kbuf);
1594
1595         /* Parse the user data */
1596         ret = -EINVAL;
1597         noffsets = 0;
1598         for (pos = kbuf; pos; pos = next_line) {
1599                 struct proc_timens_offset *off = &offsets[noffsets];
1600                 char clock[10];
1601                 int err;
1602
1603                 /* Find the end of line and ensure we don't look past it */
1604                 next_line = strchr(pos, '\n');
1605                 if (next_line) {
1606                         *next_line = '\0';
1607                         next_line++;
1608                         if (*next_line == '\0')
1609                                 next_line = NULL;
1610                 }
1611
1612                 err = sscanf(pos, "%9s %lld %lu", clock,
1613                                 &off->val.tv_sec, &off->val.tv_nsec);
1614                 if (err != 3 || off->val.tv_nsec >= NSEC_PER_SEC)
1615                         goto out;
1616
1617                 clock[sizeof(clock) - 1] = 0;
1618                 if (strcmp(clock, "monotonic") == 0 ||
1619                     strcmp(clock, __stringify(CLOCK_MONOTONIC)) == 0)
1620                         off->clockid = CLOCK_MONOTONIC;
1621                 else if (strcmp(clock, "boottime") == 0 ||
1622                          strcmp(clock, __stringify(CLOCK_BOOTTIME)) == 0)
1623                         off->clockid = CLOCK_BOOTTIME;
1624                 else
1625                         goto out;
1626
1627                 noffsets++;
1628                 if (noffsets == ARRAY_SIZE(offsets)) {
1629                         if (next_line)
1630                                 count = next_line - kbuf;
1631                         break;
1632                 }
1633         }
1634
1635         ret = -ESRCH;
1636         p = get_proc_task(inode);
1637         if (!p)
1638                 goto out;
1639         ret = proc_timens_set_offset(file, p, offsets, noffsets);
1640         put_task_struct(p);
1641         if (ret)
1642                 goto out;
1643
1644         ret = count;
1645 out:
1646         kfree(kbuf);
1647         return ret;
1648 }
1649
1650 static int timens_offsets_open(struct inode *inode, struct file *filp)
1651 {
1652         return single_open(filp, timens_offsets_show, inode);
1653 }
1654
1655 static const struct file_operations proc_timens_offsets_operations = {
1656         .open           = timens_offsets_open,
1657         .read           = seq_read,
1658         .write          = timens_offsets_write,
1659         .llseek         = seq_lseek,
1660         .release        = single_release,
1661 };
1662 #endif /* CONFIG_TIME_NS */
1663
1664 static ssize_t comm_write(struct file *file, const char __user *buf,
1665                                 size_t count, loff_t *offset)
1666 {
1667         struct inode *inode = file_inode(file);
1668         struct task_struct *p;
1669         char buffer[TASK_COMM_LEN];
1670         const size_t maxlen = sizeof(buffer) - 1;
1671
1672         memset(buffer, 0, sizeof(buffer));
1673         if (copy_from_user(buffer, buf, count > maxlen ? maxlen : count))
1674                 return -EFAULT;
1675
1676         p = get_proc_task(inode);
1677         if (!p)
1678                 return -ESRCH;
1679
1680         if (same_thread_group(current, p)) {
1681                 set_task_comm(p, buffer);
1682                 proc_comm_connector(p);
1683         }
1684         else
1685                 count = -EINVAL;
1686
1687         put_task_struct(p);
1688
1689         return count;
1690 }
1691
1692 static int comm_show(struct seq_file *m, void *v)
1693 {
1694         struct inode *inode = m->private;
1695         struct task_struct *p;
1696
1697         p = get_proc_task(inode);
1698         if (!p)
1699                 return -ESRCH;
1700
1701         proc_task_name(m, p, false);
1702         seq_putc(m, '\n');
1703
1704         put_task_struct(p);
1705
1706         return 0;
1707 }
1708
1709 static int comm_open(struct inode *inode, struct file *filp)
1710 {
1711         return single_open(filp, comm_show, inode);
1712 }
1713
1714 static const struct file_operations proc_pid_set_comm_operations = {
1715         .open           = comm_open,
1716         .read           = seq_read,
1717         .write          = comm_write,
1718         .llseek         = seq_lseek,
1719         .release        = single_release,
1720 };
1721
1722 static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
1723 {
1724         struct task_struct *task;
1725         struct file *exe_file;
1726
1727         task = get_proc_task(d_inode(dentry));
1728         if (!task)
1729                 return -ENOENT;
1730         exe_file = get_task_exe_file(task);
1731         put_task_struct(task);
1732         if (exe_file) {
1733                 *exe_path = exe_file->f_path;
1734                 path_get(&exe_file->f_path);
1735                 fput(exe_file);
1736                 return 0;
1737         } else
1738                 return -ENOENT;
1739 }
1740
1741 static const char *proc_pid_get_link(struct dentry *dentry,
1742                                      struct inode *inode,
1743                                      struct delayed_call *done)
1744 {
1745         struct path path;
1746         int error = -EACCES;
1747
1748         if (!dentry)
1749                 return ERR_PTR(-ECHILD);
1750
1751         /* Are we allowed to snoop on the tasks file descriptors? */
1752         if (!proc_fd_access_allowed(inode))
1753                 goto out;
1754
1755         error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1756         if (error)
1757                 goto out;
1758
1759         error = nd_jump_link(&path);
1760 out:
1761         return ERR_PTR(error);
1762 }
1763
1764 static int do_proc_readlink(struct path *path, char __user *buffer, int buflen)
1765 {
1766         char *tmp = kmalloc(PATH_MAX, GFP_KERNEL);
1767         char *pathname;
1768         int len;
1769
1770         if (!tmp)
1771                 return -ENOMEM;
1772
1773         pathname = d_path(path, tmp, PATH_MAX);
1774         len = PTR_ERR(pathname);
1775         if (IS_ERR(pathname))
1776                 goto out;
1777         len = tmp + PATH_MAX - 1 - pathname;
1778
1779         if (len > buflen)
1780                 len = buflen;
1781         if (copy_to_user(buffer, pathname, len))
1782                 len = -EFAULT;
1783  out:
1784         kfree(tmp);
1785         return len;
1786 }
1787
1788 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1789 {
1790         int error = -EACCES;
1791         struct inode *inode = d_inode(dentry);
1792         struct path path;
1793
1794         /* Are we allowed to snoop on the tasks file descriptors? */
1795         if (!proc_fd_access_allowed(inode))
1796                 goto out;
1797
1798         error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1799         if (error)
1800                 goto out;
1801
1802         error = do_proc_readlink(&path, buffer, buflen);
1803         path_put(&path);
1804 out:
1805         return error;
1806 }
1807
1808 const struct inode_operations proc_pid_link_inode_operations = {
1809         .readlink       = proc_pid_readlink,
1810         .get_link       = proc_pid_get_link,
1811         .setattr        = proc_setattr,
1812 };
1813
1814
1815 /* building an inode */
1816
1817 void task_dump_owner(struct task_struct *task, umode_t mode,
1818                      kuid_t *ruid, kgid_t *rgid)
1819 {
1820         /* Depending on the state of dumpable compute who should own a
1821          * proc file for a task.
1822          */
1823         const struct cred *cred;
1824         kuid_t uid;
1825         kgid_t gid;
1826
1827         if (unlikely(task->flags & PF_KTHREAD)) {
1828                 *ruid = GLOBAL_ROOT_UID;
1829                 *rgid = GLOBAL_ROOT_GID;
1830                 return;
1831         }
1832
1833         /* Default to the tasks effective ownership */
1834         rcu_read_lock();
1835         cred = __task_cred(task);
1836         uid = cred->euid;
1837         gid = cred->egid;
1838         rcu_read_unlock();
1839
1840         /*
1841          * Before the /proc/pid/status file was created the only way to read
1842          * the effective uid of a /process was to stat /proc/pid.  Reading
1843          * /proc/pid/status is slow enough that procps and other packages
1844          * kept stating /proc/pid.  To keep the rules in /proc simple I have
1845          * made this apply to all per process world readable and executable
1846          * directories.
1847          */
1848         if (mode != (S_IFDIR|S_IRUGO|S_IXUGO)) {
1849                 struct mm_struct *mm;
1850                 task_lock(task);
1851                 mm = task->mm;
1852                 /* Make non-dumpable tasks owned by some root */
1853                 if (mm) {
1854                         if (get_dumpable(mm) != SUID_DUMP_USER) {
1855                                 struct user_namespace *user_ns = mm->user_ns;
1856
1857                                 uid = make_kuid(user_ns, 0);
1858                                 if (!uid_valid(uid))
1859                                         uid = GLOBAL_ROOT_UID;
1860
1861                                 gid = make_kgid(user_ns, 0);
1862                                 if (!gid_valid(gid))
1863                                         gid = GLOBAL_ROOT_GID;
1864                         }
1865                 } else {
1866                         uid = GLOBAL_ROOT_UID;
1867                         gid = GLOBAL_ROOT_GID;
1868                 }
1869                 task_unlock(task);
1870         }
1871         *ruid = uid;
1872         *rgid = gid;
1873 }
1874
1875 void proc_pid_evict_inode(struct proc_inode *ei)
1876 {
1877         struct pid *pid = ei->pid;
1878
1879         if (S_ISDIR(ei->vfs_inode.i_mode)) {
1880                 spin_lock(&pid->lock);
1881                 hlist_del_init_rcu(&ei->sibling_inodes);
1882                 spin_unlock(&pid->lock);
1883         }
1884
1885         put_pid(pid);
1886 }
1887
1888 struct inode *proc_pid_make_inode(struct super_block * sb,
1889                                   struct task_struct *task, umode_t mode)
1890 {
1891         struct inode * inode;
1892         struct proc_inode *ei;
1893         struct pid *pid;
1894
1895         /* We need a new inode */
1896
1897         inode = new_inode(sb);
1898         if (!inode)
1899                 goto out;
1900
1901         /* Common stuff */
1902         ei = PROC_I(inode);
1903         inode->i_mode = mode;
1904         inode->i_ino = get_next_ino();
1905         inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
1906         inode->i_op = &proc_def_inode_operations;
1907
1908         /*
1909          * grab the reference to task.
1910          */
1911         pid = get_task_pid(task, PIDTYPE_PID);
1912         if (!pid)
1913                 goto out_unlock;
1914
1915         /* Let the pid remember us for quick removal */
1916         ei->pid = pid;
1917         if (S_ISDIR(mode)) {
1918                 spin_lock(&pid->lock);
1919                 hlist_add_head_rcu(&ei->sibling_inodes, &pid->inodes);
1920                 spin_unlock(&pid->lock);
1921         }
1922
1923         task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
1924         security_task_to_inode(task, inode);
1925
1926 out:
1927         return inode;
1928
1929 out_unlock:
1930         iput(inode);
1931         return NULL;
1932 }
1933
1934 int pid_getattr(struct user_namespace *mnt_userns, const struct path *path,
1935                 struct kstat *stat, u32 request_mask, unsigned int query_flags)
1936 {
1937         struct inode *inode = d_inode(path->dentry);
1938         struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb);
1939         struct task_struct *task;
1940
1941         generic_fillattr(&init_user_ns, inode, stat);
1942
1943         stat->uid = GLOBAL_ROOT_UID;
1944         stat->gid = GLOBAL_ROOT_GID;
1945         rcu_read_lock();
1946         task = pid_task(proc_pid(inode), PIDTYPE_PID);
1947         if (task) {
1948                 if (!has_pid_permissions(fs_info, task, HIDEPID_INVISIBLE)) {
1949                         rcu_read_unlock();
1950                         /*
1951                          * This doesn't prevent learning whether PID exists,
1952                          * it only makes getattr() consistent with readdir().
1953                          */
1954                         return -ENOENT;
1955                 }
1956                 task_dump_owner(task, inode->i_mode, &stat->uid, &stat->gid);
1957         }
1958         rcu_read_unlock();
1959         return 0;
1960 }
1961
1962 /* dentry stuff */
1963
1964 /*
1965  * Set <pid>/... inode ownership (can change due to setuid(), etc.)
1966  */
1967 void pid_update_inode(struct task_struct *task, struct inode *inode)
1968 {
1969         task_dump_owner(task, inode->i_mode, &inode->i_uid, &inode->i_gid);
1970
1971         inode->i_mode &= ~(S_ISUID | S_ISGID);
1972         security_task_to_inode(task, inode);
1973 }
1974
1975 /*
1976  * Rewrite the inode's ownerships here because the owning task may have
1977  * performed a setuid(), etc.
1978  *
1979  */
1980 static int pid_revalidate(struct dentry *dentry, unsigned int flags)
1981 {
1982         struct inode *inode;
1983         struct task_struct *task;
1984         int ret = 0;
1985
1986         rcu_read_lock();
1987         inode = d_inode_rcu(dentry);
1988         if (!inode)
1989                 goto out;
1990         task = pid_task(proc_pid(inode), PIDTYPE_PID);
1991
1992         if (task) {
1993                 pid_update_inode(task, inode);
1994                 ret = 1;
1995         }
1996 out:
1997         rcu_read_unlock();
1998         return ret;
1999 }
2000
2001 static inline bool proc_inode_is_dead(struct inode *inode)
2002 {
2003         return !proc_pid(inode)->tasks[PIDTYPE_PID].first;
2004 }
2005
2006 int pid_delete_dentry(const struct dentry *dentry)
2007 {
2008         /* Is the task we represent dead?
2009          * If so, then don't put the dentry on the lru list,
2010          * kill it immediately.
2011          */
2012         return proc_inode_is_dead(d_inode(dentry));
2013 }
2014
2015 const struct dentry_operations pid_dentry_operations =
2016 {
2017         .d_revalidate   = pid_revalidate,
2018         .d_delete       = pid_delete_dentry,
2019 };
2020
2021 /* Lookups */
2022
2023 /*
2024  * Fill a directory entry.
2025  *
2026  * If possible create the dcache entry and derive our inode number and
2027  * file type from dcache entry.
2028  *
2029  * Since all of the proc inode numbers are dynamically generated, the inode
2030  * numbers do not exist until the inode is cache.  This means creating
2031  * the dcache entry in readdir is necessary to keep the inode numbers
2032  * reported by readdir in sync with the inode numbers reported
2033  * by stat.
2034  */
2035 bool proc_fill_cache(struct file *file, struct dir_context *ctx,
2036         const char *name, unsigned int len,
2037         instantiate_t instantiate, struct task_struct *task, const void *ptr)
2038 {
2039         struct dentry *child, *dir = file->f_path.dentry;
2040         struct qstr qname = QSTR_INIT(name, len);
2041         struct inode *inode;
2042         unsigned type = DT_UNKNOWN;
2043         ino_t ino = 1;
2044
2045         child = d_hash_and_lookup(dir, &qname);
2046         if (!child) {
2047                 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
2048                 child = d_alloc_parallel(dir, &qname, &wq);
2049                 if (IS_ERR(child))
2050                         goto end_instantiate;
2051                 if (d_in_lookup(child)) {
2052                         struct dentry *res;
2053                         res = instantiate(child, task, ptr);
2054                         d_lookup_done(child);
2055                         if (unlikely(res)) {
2056                                 dput(child);
2057                                 child = res;
2058                                 if (IS_ERR(child))
2059                                         goto end_instantiate;
2060                         }
2061                 }
2062         }
2063         inode = d_inode(child);
2064         ino = inode->i_ino;
2065         type = inode->i_mode >> 12;
2066         dput(child);
2067 end_instantiate:
2068         return dir_emit(ctx, name, len, ino, type);
2069 }
2070
2071 /*
2072  * dname_to_vma_addr - maps a dentry name into two unsigned longs
2073  * which represent vma start and end addresses.
2074  */
2075 static int dname_to_vma_addr(struct dentry *dentry,
2076                              unsigned long *start, unsigned long *end)
2077 {
2078         const char *str = dentry->d_name.name;
2079         unsigned long long sval, eval;
2080         unsigned int len;
2081
2082         if (str[0] == '0' && str[1] != '-')
2083                 return -EINVAL;
2084         len = _parse_integer(str, 16, &sval);
2085         if (len & KSTRTOX_OVERFLOW)
2086                 return -EINVAL;
2087         if (sval != (unsigned long)sval)
2088                 return -EINVAL;
2089         str += len;
2090
2091         if (*str != '-')
2092                 return -EINVAL;
2093         str++;
2094
2095         if (str[0] == '0' && str[1])
2096                 return -EINVAL;
2097         len = _parse_integer(str, 16, &eval);
2098         if (len & KSTRTOX_OVERFLOW)
2099                 return -EINVAL;
2100         if (eval != (unsigned long)eval)
2101                 return -EINVAL;
2102         str += len;
2103
2104         if (*str != '\0')
2105                 return -EINVAL;
2106
2107         *start = sval;
2108         *end = eval;
2109
2110         return 0;
2111 }
2112
2113 static int map_files_d_revalidate(struct dentry *dentry, unsigned int flags)
2114 {
2115         unsigned long vm_start, vm_end;
2116         bool exact_vma_exists = false;
2117         struct mm_struct *mm = NULL;
2118         struct task_struct *task;
2119         struct inode *inode;
2120         int status = 0;
2121
2122         if (flags & LOOKUP_RCU)
2123                 return -ECHILD;
2124
2125         inode = d_inode(dentry);
2126         task = get_proc_task(inode);
2127         if (!task)
2128                 goto out_notask;
2129
2130         mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
2131         if (IS_ERR_OR_NULL(mm))
2132                 goto out;
2133
2134         if (!dname_to_vma_addr(dentry, &vm_start, &vm_end)) {
2135                 status = mmap_read_lock_killable(mm);
2136                 if (!status) {
2137                         exact_vma_exists = !!find_exact_vma(mm, vm_start,
2138                                                             vm_end);
2139                         mmap_read_unlock(mm);
2140                 }
2141         }
2142
2143         mmput(mm);
2144
2145         if (exact_vma_exists) {
2146                 task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
2147
2148                 security_task_to_inode(task, inode);
2149                 status = 1;
2150         }
2151
2152 out:
2153         put_task_struct(task);
2154
2155 out_notask:
2156         return status;
2157 }
2158
2159 static const struct dentry_operations tid_map_files_dentry_operations = {
2160         .d_revalidate   = map_files_d_revalidate,
2161         .d_delete       = pid_delete_dentry,
2162 };
2163
2164 static int map_files_get_link(struct dentry *dentry, struct path *path)
2165 {
2166         unsigned long vm_start, vm_end;
2167         struct vm_area_struct *vma;
2168         struct task_struct *task;
2169         struct mm_struct *mm;
2170         int rc;
2171
2172         rc = -ENOENT;
2173         task = get_proc_task(d_inode(dentry));
2174         if (!task)
2175                 goto out;
2176
2177         mm = get_task_mm(task);
2178         put_task_struct(task);
2179         if (!mm)
2180                 goto out;
2181
2182         rc = dname_to_vma_addr(dentry, &vm_start, &vm_end);
2183         if (rc)
2184                 goto out_mmput;
2185
2186         rc = mmap_read_lock_killable(mm);
2187         if (rc)
2188                 goto out_mmput;
2189
2190         rc = -ENOENT;
2191         vma = find_exact_vma(mm, vm_start, vm_end);
2192         if (vma && vma->vm_file) {
2193                 *path = vma->vm_file->f_path;
2194                 path_get(path);
2195                 rc = 0;
2196         }
2197         mmap_read_unlock(mm);
2198
2199 out_mmput:
2200         mmput(mm);
2201 out:
2202         return rc;
2203 }
2204
2205 struct map_files_info {
2206         unsigned long   start;
2207         unsigned long   end;
2208         fmode_t         mode;
2209 };
2210
2211 /*
2212  * Only allow CAP_SYS_ADMIN and CAP_CHECKPOINT_RESTORE to follow the links, due
2213  * to concerns about how the symlinks may be used to bypass permissions on
2214  * ancestor directories in the path to the file in question.
2215  */
2216 static const char *
2217 proc_map_files_get_link(struct dentry *dentry,
2218                         struct inode *inode,
2219                         struct delayed_call *done)
2220 {
2221         if (!checkpoint_restore_ns_capable(&init_user_ns))
2222                 return ERR_PTR(-EPERM);
2223
2224         return proc_pid_get_link(dentry, inode, done);
2225 }
2226
2227 /*
2228  * Identical to proc_pid_link_inode_operations except for get_link()
2229  */
2230 static const struct inode_operations proc_map_files_link_inode_operations = {
2231         .readlink       = proc_pid_readlink,
2232         .get_link       = proc_map_files_get_link,
2233         .setattr        = proc_setattr,
2234 };
2235
2236 static struct dentry *
2237 proc_map_files_instantiate(struct dentry *dentry,
2238                            struct task_struct *task, const void *ptr)
2239 {
2240         fmode_t mode = (fmode_t)(unsigned long)ptr;
2241         struct proc_inode *ei;
2242         struct inode *inode;
2243
2244         inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK |
2245                                     ((mode & FMODE_READ ) ? S_IRUSR : 0) |
2246                                     ((mode & FMODE_WRITE) ? S_IWUSR : 0));
2247         if (!inode)
2248                 return ERR_PTR(-ENOENT);
2249
2250         ei = PROC_I(inode);
2251         ei->op.proc_get_link = map_files_get_link;
2252
2253         inode->i_op = &proc_map_files_link_inode_operations;
2254         inode->i_size = 64;
2255
2256         d_set_d_op(dentry, &tid_map_files_dentry_operations);
2257         return d_splice_alias(inode, dentry);
2258 }
2259
2260 static struct dentry *proc_map_files_lookup(struct inode *dir,
2261                 struct dentry *dentry, unsigned int flags)
2262 {
2263         unsigned long vm_start, vm_end;
2264         struct vm_area_struct *vma;
2265         struct task_struct *task;
2266         struct dentry *result;
2267         struct mm_struct *mm;
2268
2269         result = ERR_PTR(-ENOENT);
2270         task = get_proc_task(dir);
2271         if (!task)
2272                 goto out;
2273
2274         result = ERR_PTR(-EACCES);
2275         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2276                 goto out_put_task;
2277
2278         result = ERR_PTR(-ENOENT);
2279         if (dname_to_vma_addr(dentry, &vm_start, &vm_end))
2280                 goto out_put_task;
2281
2282         mm = get_task_mm(task);
2283         if (!mm)
2284                 goto out_put_task;
2285
2286         result = ERR_PTR(-EINTR);
2287         if (mmap_read_lock_killable(mm))
2288                 goto out_put_mm;
2289
2290         result = ERR_PTR(-ENOENT);
2291         vma = find_exact_vma(mm, vm_start, vm_end);
2292         if (!vma)
2293                 goto out_no_vma;
2294
2295         if (vma->vm_file)
2296                 result = proc_map_files_instantiate(dentry, task,
2297                                 (void *)(unsigned long)vma->vm_file->f_mode);
2298
2299 out_no_vma:
2300         mmap_read_unlock(mm);
2301 out_put_mm:
2302         mmput(mm);
2303 out_put_task:
2304         put_task_struct(task);
2305 out:
2306         return result;
2307 }
2308
2309 static const struct inode_operations proc_map_files_inode_operations = {
2310         .lookup         = proc_map_files_lookup,
2311         .permission     = proc_fd_permission,
2312         .setattr        = proc_setattr,
2313 };
2314
2315 static int
2316 proc_map_files_readdir(struct file *file, struct dir_context *ctx)
2317 {
2318         struct vm_area_struct *vma;
2319         struct task_struct *task;
2320         struct mm_struct *mm;
2321         unsigned long nr_files, pos, i;
2322         GENRADIX(struct map_files_info) fa;
2323         struct map_files_info *p;
2324         int ret;
2325
2326         genradix_init(&fa);
2327
2328         ret = -ENOENT;
2329         task = get_proc_task(file_inode(file));
2330         if (!task)
2331                 goto out;
2332
2333         ret = -EACCES;
2334         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2335                 goto out_put_task;
2336
2337         ret = 0;
2338         if (!dir_emit_dots(file, ctx))
2339                 goto out_put_task;
2340
2341         mm = get_task_mm(task);
2342         if (!mm)
2343                 goto out_put_task;
2344
2345         ret = mmap_read_lock_killable(mm);
2346         if (ret) {
2347                 mmput(mm);
2348                 goto out_put_task;
2349         }
2350
2351         nr_files = 0;
2352
2353         /*
2354          * We need two passes here:
2355          *
2356          *  1) Collect vmas of mapped files with mmap_lock taken
2357          *  2) Release mmap_lock and instantiate entries
2358          *
2359          * otherwise we get lockdep complained, since filldir()
2360          * routine might require mmap_lock taken in might_fault().
2361          */
2362
2363         for (vma = mm->mmap, pos = 2; vma; vma = vma->vm_next) {
2364                 if (!vma->vm_file)
2365                         continue;
2366                 if (++pos <= ctx->pos)
2367                         continue;
2368
2369                 p = genradix_ptr_alloc(&fa, nr_files++, GFP_KERNEL);
2370                 if (!p) {
2371                         ret = -ENOMEM;
2372                         mmap_read_unlock(mm);
2373                         mmput(mm);
2374                         goto out_put_task;
2375                 }
2376
2377                 p->start = vma->vm_start;
2378                 p->end = vma->vm_end;
2379                 p->mode = vma->vm_file->f_mode;
2380         }
2381         mmap_read_unlock(mm);
2382         mmput(mm);
2383
2384         for (i = 0; i < nr_files; i++) {
2385                 char buf[4 * sizeof(long) + 2]; /* max: %lx-%lx\0 */
2386                 unsigned int len;
2387
2388                 p = genradix_ptr(&fa, i);
2389                 len = snprintf(buf, sizeof(buf), "%lx-%lx", p->start, p->end);
2390                 if (!proc_fill_cache(file, ctx,
2391                                       buf, len,
2392                                       proc_map_files_instantiate,
2393                                       task,
2394                                       (void *)(unsigned long)p->mode))
2395                         break;
2396                 ctx->pos++;
2397         }
2398
2399 out_put_task:
2400         put_task_struct(task);
2401 out:
2402         genradix_free(&fa);
2403         return ret;
2404 }
2405
2406 static const struct file_operations proc_map_files_operations = {
2407         .read           = generic_read_dir,
2408         .iterate_shared = proc_map_files_readdir,
2409         .llseek         = generic_file_llseek,
2410 };
2411
2412 #if defined(CONFIG_CHECKPOINT_RESTORE) && defined(CONFIG_POSIX_TIMERS)
2413 struct timers_private {
2414         struct pid *pid;
2415         struct task_struct *task;
2416         struct sighand_struct *sighand;
2417         struct pid_namespace *ns;
2418         unsigned long flags;
2419 };
2420
2421 static void *timers_start(struct seq_file *m, loff_t *pos)
2422 {
2423         struct timers_private *tp = m->private;
2424
2425         tp->task = get_pid_task(tp->pid, PIDTYPE_PID);
2426         if (!tp->task)
2427                 return ERR_PTR(-ESRCH);
2428
2429         tp->sighand = lock_task_sighand(tp->task, &tp->flags);
2430         if (!tp->sighand)
2431                 return ERR_PTR(-ESRCH);
2432
2433         return seq_list_start(&tp->task->signal->posix_timers, *pos);
2434 }
2435
2436 static void *timers_next(struct seq_file *m, void *v, loff_t *pos)
2437 {
2438         struct timers_private *tp = m->private;
2439         return seq_list_next(v, &tp->task->signal->posix_timers, pos);
2440 }
2441
2442 static void timers_stop(struct seq_file *m, void *v)
2443 {
2444         struct timers_private *tp = m->private;
2445
2446         if (tp->sighand) {
2447                 unlock_task_sighand(tp->task, &tp->flags);
2448                 tp->sighand = NULL;
2449         }
2450
2451         if (tp->task) {
2452                 put_task_struct(tp->task);
2453                 tp->task = NULL;
2454         }
2455 }
2456
2457 static int show_timer(struct seq_file *m, void *v)
2458 {
2459         struct k_itimer *timer;
2460         struct timers_private *tp = m->private;
2461         int notify;
2462         static const char * const nstr[] = {
2463                 [SIGEV_SIGNAL] = "signal",
2464                 [SIGEV_NONE] = "none",
2465                 [SIGEV_THREAD] = "thread",
2466         };
2467
2468         timer = list_entry((struct list_head *)v, struct k_itimer, list);
2469         notify = timer->it_sigev_notify;
2470
2471         seq_printf(m, "ID: %d\n", timer->it_id);
2472         seq_printf(m, "signal: %d/%px\n",
2473                    timer->sigq->info.si_signo,
2474                    timer->sigq->info.si_value.sival_ptr);
2475         seq_printf(m, "notify: %s/%s.%d\n",
2476                    nstr[notify & ~SIGEV_THREAD_ID],
2477                    (notify & SIGEV_THREAD_ID) ? "tid" : "pid",
2478                    pid_nr_ns(timer->it_pid, tp->ns));
2479         seq_printf(m, "ClockID: %d\n", timer->it_clock);
2480
2481         return 0;
2482 }
2483
2484 static const struct seq_operations proc_timers_seq_ops = {
2485         .start  = timers_start,
2486         .next   = timers_next,
2487         .stop   = timers_stop,
2488         .show   = show_timer,
2489 };
2490
2491 static int proc_timers_open(struct inode *inode, struct file *file)
2492 {
2493         struct timers_private *tp;
2494
2495         tp = __seq_open_private(file, &proc_timers_seq_ops,
2496                         sizeof(struct timers_private));
2497         if (!tp)
2498                 return -ENOMEM;
2499
2500         tp->pid = proc_pid(inode);
2501         tp->ns = proc_pid_ns(inode->i_sb);
2502         return 0;
2503 }
2504
2505 static const struct file_operations proc_timers_operations = {
2506         .open           = proc_timers_open,
2507         .read           = seq_read,
2508         .llseek         = seq_lseek,
2509         .release        = seq_release_private,
2510 };
2511 #endif
2512
2513 static ssize_t timerslack_ns_write(struct file *file, const char __user *buf,
2514                                         size_t count, loff_t *offset)
2515 {
2516         struct inode *inode = file_inode(file);
2517         struct task_struct *p;
2518         u64 slack_ns;
2519         int err;
2520
2521         err = kstrtoull_from_user(buf, count, 10, &slack_ns);
2522         if (err < 0)
2523                 return err;
2524
2525         p = get_proc_task(inode);
2526         if (!p)
2527                 return -ESRCH;
2528
2529         if (p != current) {
2530                 rcu_read_lock();
2531                 if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
2532                         rcu_read_unlock();
2533                         count = -EPERM;
2534                         goto out;
2535                 }
2536                 rcu_read_unlock();
2537
2538                 err = security_task_setscheduler(p);
2539                 if (err) {
2540                         count = err;
2541                         goto out;
2542                 }
2543         }
2544
2545         task_lock(p);
2546         if (slack_ns == 0)
2547                 p->timer_slack_ns = p->default_timer_slack_ns;
2548         else
2549                 p->timer_slack_ns = slack_ns;
2550         task_unlock(p);
2551
2552 out:
2553         put_task_struct(p);
2554
2555         return count;
2556 }
2557
2558 static int timerslack_ns_show(struct seq_file *m, void *v)
2559 {
2560         struct inode *inode = m->private;
2561         struct task_struct *p;
2562         int err = 0;
2563
2564         p = get_proc_task(inode);
2565         if (!p)
2566                 return -ESRCH;
2567
2568         if (p != current) {
2569                 rcu_read_lock();
2570                 if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
2571                         rcu_read_unlock();
2572                         err = -EPERM;
2573                         goto out;
2574                 }
2575                 rcu_read_unlock();
2576
2577                 err = security_task_getscheduler(p);
2578                 if (err)
2579                         goto out;
2580         }
2581
2582         task_lock(p);
2583         seq_printf(m, "%llu\n", p->timer_slack_ns);
2584         task_unlock(p);
2585
2586 out:
2587         put_task_struct(p);
2588
2589         return err;
2590 }
2591
2592 static int timerslack_ns_open(struct inode *inode, struct file *filp)
2593 {
2594         return single_open(filp, timerslack_ns_show, inode);
2595 }
2596
2597 static const struct file_operations proc_pid_set_timerslack_ns_operations = {
2598         .open           = timerslack_ns_open,
2599         .read           = seq_read,
2600         .write          = timerslack_ns_write,
2601         .llseek         = seq_lseek,
2602         .release        = single_release,
2603 };
2604
2605 static struct dentry *proc_pident_instantiate(struct dentry *dentry,
2606         struct task_struct *task, const void *ptr)
2607 {
2608         const struct pid_entry *p = ptr;
2609         struct inode *inode;
2610         struct proc_inode *ei;
2611
2612         inode = proc_pid_make_inode(dentry->d_sb, task, p->mode);
2613         if (!inode)
2614                 return ERR_PTR(-ENOENT);
2615
2616         ei = PROC_I(inode);
2617         if (S_ISDIR(inode->i_mode))
2618                 set_nlink(inode, 2);    /* Use getattr to fix if necessary */
2619         if (p->iop)
2620                 inode->i_op = p->iop;
2621         if (p->fop)
2622                 inode->i_fop = p->fop;
2623         ei->op = p->op;
2624         pid_update_inode(task, inode);
2625         d_set_d_op(dentry, &pid_dentry_operations);
2626         return d_splice_alias(inode, dentry);
2627 }
2628
2629 static struct dentry *proc_pident_lookup(struct inode *dir,
2630                                          struct dentry *dentry,
2631                                          const struct pid_entry *p,
2632                                          const struct pid_entry *end)
2633 {
2634         struct task_struct *task = get_proc_task(dir);
2635         struct dentry *res = ERR_PTR(-ENOENT);
2636
2637         if (!task)
2638                 goto out_no_task;
2639
2640         /*
2641          * Yes, it does not scale. And it should not. Don't add
2642          * new entries into /proc/<tgid>/ without very good reasons.
2643          */
2644         for (; p < end; p++) {
2645                 if (p->len != dentry->d_name.len)
2646                         continue;
2647                 if (!memcmp(dentry->d_name.name, p->name, p->len)) {
2648                         res = proc_pident_instantiate(dentry, task, p);
2649                         break;
2650                 }
2651         }
2652         put_task_struct(task);
2653 out_no_task:
2654         return res;
2655 }
2656
2657 static int proc_pident_readdir(struct file *file, struct dir_context *ctx,
2658                 const struct pid_entry *ents, unsigned int nents)
2659 {
2660         struct task_struct *task = get_proc_task(file_inode(file));
2661         const struct pid_entry *p;
2662
2663         if (!task)
2664                 return -ENOENT;
2665
2666         if (!dir_emit_dots(file, ctx))
2667                 goto out;
2668
2669         if (ctx->pos >= nents + 2)
2670                 goto out;
2671
2672         for (p = ents + (ctx->pos - 2); p < ents + nents; p++) {
2673                 if (!proc_fill_cache(file, ctx, p->name, p->len,
2674                                 proc_pident_instantiate, task, p))
2675                         break;
2676                 ctx->pos++;
2677         }
2678 out:
2679         put_task_struct(task);
2680         return 0;
2681 }
2682
2683 #ifdef CONFIG_SECURITY
2684 static int proc_pid_attr_open(struct inode *inode, struct file *file)
2685 {
2686         file->private_data = NULL;
2687         __mem_open(inode, file, PTRACE_MODE_READ_FSCREDS);
2688         return 0;
2689 }
2690
2691 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
2692                                   size_t count, loff_t *ppos)
2693 {
2694         struct inode * inode = file_inode(file);
2695         char *p = NULL;
2696         ssize_t length;
2697         struct task_struct *task = get_proc_task(inode);
2698
2699         if (!task)
2700                 return -ESRCH;
2701
2702         length = security_getprocattr(task, PROC_I(inode)->op.lsm,
2703                                       (char*)file->f_path.dentry->d_name.name,
2704                                       &p);
2705         put_task_struct(task);
2706         if (length > 0)
2707                 length = simple_read_from_buffer(buf, count, ppos, p, length);
2708         kfree(p);
2709         return length;
2710 }
2711
2712 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
2713                                    size_t count, loff_t *ppos)
2714 {
2715         struct inode * inode = file_inode(file);
2716         struct task_struct *task;
2717         void *page;
2718         int rv;
2719
2720         /* A task may only write when it was the opener. */
2721         if (file->private_data != current->mm)
2722                 return -EPERM;
2723
2724         rcu_read_lock();
2725         task = pid_task(proc_pid(inode), PIDTYPE_PID);
2726         if (!task) {
2727                 rcu_read_unlock();
2728                 return -ESRCH;
2729         }
2730         /* A task may only write its own attributes. */
2731         if (current != task) {
2732                 rcu_read_unlock();
2733                 return -EACCES;
2734         }
2735         /* Prevent changes to overridden credentials. */
2736         if (current_cred() != current_real_cred()) {
2737                 rcu_read_unlock();
2738                 return -EBUSY;
2739         }
2740         rcu_read_unlock();
2741
2742         if (count > PAGE_SIZE)
2743                 count = PAGE_SIZE;
2744
2745         /* No partial writes. */
2746         if (*ppos != 0)
2747                 return -EINVAL;
2748
2749         page = memdup_user(buf, count);
2750         if (IS_ERR(page)) {
2751                 rv = PTR_ERR(page);
2752                 goto out;
2753         }
2754
2755         /* Guard against adverse ptrace interaction */
2756         rv = mutex_lock_interruptible(&current->signal->cred_guard_mutex);
2757         if (rv < 0)
2758                 goto out_free;
2759
2760         rv = security_setprocattr(PROC_I(inode)->op.lsm,
2761                                   file->f_path.dentry->d_name.name, page,
2762                                   count);
2763         mutex_unlock(&current->signal->cred_guard_mutex);
2764 out_free:
2765         kfree(page);
2766 out:
2767         return rv;
2768 }
2769
2770 static const struct file_operations proc_pid_attr_operations = {
2771         .open           = proc_pid_attr_open,
2772         .read           = proc_pid_attr_read,
2773         .write          = proc_pid_attr_write,
2774         .llseek         = generic_file_llseek,
2775         .release        = mem_release,
2776 };
2777
2778 #define LSM_DIR_OPS(LSM) \
2779 static int proc_##LSM##_attr_dir_iterate(struct file *filp, \
2780                              struct dir_context *ctx) \
2781 { \
2782         return proc_pident_readdir(filp, ctx, \
2783                                    LSM##_attr_dir_stuff, \
2784                                    ARRAY_SIZE(LSM##_attr_dir_stuff)); \
2785 } \
2786 \
2787 static const struct file_operations proc_##LSM##_attr_dir_ops = { \
2788         .read           = generic_read_dir, \
2789         .iterate        = proc_##LSM##_attr_dir_iterate, \
2790         .llseek         = default_llseek, \
2791 }; \
2792 \
2793 static struct dentry *proc_##LSM##_attr_dir_lookup(struct inode *dir, \
2794                                 struct dentry *dentry, unsigned int flags) \
2795 { \
2796         return proc_pident_lookup(dir, dentry, \
2797                                   LSM##_attr_dir_stuff, \
2798                                   LSM##_attr_dir_stuff + ARRAY_SIZE(LSM##_attr_dir_stuff)); \
2799 } \
2800 \
2801 static const struct inode_operations proc_##LSM##_attr_dir_inode_ops = { \
2802         .lookup         = proc_##LSM##_attr_dir_lookup, \
2803         .getattr        = pid_getattr, \
2804         .setattr        = proc_setattr, \
2805 }
2806
2807 #ifdef CONFIG_SECURITY_SMACK
2808 static const struct pid_entry smack_attr_dir_stuff[] = {
2809         ATTR("smack", "current",        0666),
2810 };
2811 LSM_DIR_OPS(smack);
2812 #endif
2813
2814 #ifdef CONFIG_SECURITY_APPARMOR
2815 static const struct pid_entry apparmor_attr_dir_stuff[] = {
2816         ATTR("apparmor", "current",     0666),
2817         ATTR("apparmor", "prev",        0444),
2818         ATTR("apparmor", "exec",        0666),
2819 };
2820 LSM_DIR_OPS(apparmor);
2821 #endif
2822
2823 static const struct pid_entry attr_dir_stuff[] = {
2824         ATTR(NULL, "current",           0666),
2825         ATTR(NULL, "prev",              0444),
2826         ATTR(NULL, "exec",              0666),
2827         ATTR(NULL, "fscreate",          0666),
2828         ATTR(NULL, "keycreate",         0666),
2829         ATTR(NULL, "sockcreate",        0666),
2830 #ifdef CONFIG_SECURITY_SMACK
2831         DIR("smack",                    0555,
2832             proc_smack_attr_dir_inode_ops, proc_smack_attr_dir_ops),
2833 #endif
2834 #ifdef CONFIG_SECURITY_APPARMOR
2835         DIR("apparmor",                 0555,
2836             proc_apparmor_attr_dir_inode_ops, proc_apparmor_attr_dir_ops),
2837 #endif
2838 };
2839
2840 static int proc_attr_dir_readdir(struct file *file, struct dir_context *ctx)
2841 {
2842         return proc_pident_readdir(file, ctx,
2843                                    attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2844 }
2845
2846 static const struct file_operations proc_attr_dir_operations = {
2847         .read           = generic_read_dir,
2848         .iterate_shared = proc_attr_dir_readdir,
2849         .llseek         = generic_file_llseek,
2850 };
2851
2852 static struct dentry *proc_attr_dir_lookup(struct inode *dir,
2853                                 struct dentry *dentry, unsigned int flags)
2854 {
2855         return proc_pident_lookup(dir, dentry,
2856                                   attr_dir_stuff,
2857                                   attr_dir_stuff + ARRAY_SIZE(attr_dir_stuff));
2858 }
2859
2860 static const struct inode_operations proc_attr_dir_inode_operations = {
2861         .lookup         = proc_attr_dir_lookup,
2862         .getattr        = pid_getattr,
2863         .setattr        = proc_setattr,
2864 };
2865
2866 #endif
2867
2868 #ifdef CONFIG_ELF_CORE
2869 static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
2870                                          size_t count, loff_t *ppos)
2871 {
2872         struct task_struct *task = get_proc_task(file_inode(file));
2873         struct mm_struct *mm;
2874         char buffer[PROC_NUMBUF];
2875         size_t len;
2876         int ret;
2877
2878         if (!task)
2879                 return -ESRCH;
2880
2881         ret = 0;
2882         mm = get_task_mm(task);
2883         if (mm) {
2884                 len = snprintf(buffer, sizeof(buffer), "%08lx\n",
2885                                ((mm->flags & MMF_DUMP_FILTER_MASK) >>
2886                                 MMF_DUMP_FILTER_SHIFT));
2887                 mmput(mm);
2888                 ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
2889         }
2890
2891         put_task_struct(task);
2892
2893         return ret;
2894 }
2895
2896 static ssize_t proc_coredump_filter_write(struct file *file,
2897                                           const char __user *buf,
2898                                           size_t count,
2899                                           loff_t *ppos)
2900 {
2901         struct task_struct *task;
2902         struct mm_struct *mm;
2903         unsigned int val;
2904         int ret;
2905         int i;
2906         unsigned long mask;
2907
2908         ret = kstrtouint_from_user(buf, count, 0, &val);
2909         if (ret < 0)
2910                 return ret;
2911
2912         ret = -ESRCH;
2913         task = get_proc_task(file_inode(file));
2914         if (!task)
2915                 goto out_no_task;
2916
2917         mm = get_task_mm(task);
2918         if (!mm)
2919                 goto out_no_mm;
2920         ret = 0;
2921
2922         for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
2923                 if (val & mask)
2924                         set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2925                 else
2926                         clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2927         }
2928
2929         mmput(mm);
2930  out_no_mm:
2931         put_task_struct(task);
2932  out_no_task:
2933         if (ret < 0)
2934                 return ret;
2935         return count;
2936 }
2937
2938 static const struct file_operations proc_coredump_filter_operations = {
2939         .read           = proc_coredump_filter_read,
2940         .write          = proc_coredump_filter_write,
2941         .llseek         = generic_file_llseek,
2942 };
2943 #endif
2944
2945 #ifdef CONFIG_TASK_IO_ACCOUNTING
2946 static int do_io_accounting(struct task_struct *task, struct seq_file *m, int whole)
2947 {
2948         struct task_io_accounting acct = task->ioac;
2949         unsigned long flags;
2950         int result;
2951
2952         result = down_read_killable(&task->signal->exec_update_lock);
2953         if (result)
2954                 return result;
2955
2956         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
2957                 result = -EACCES;
2958                 goto out_unlock;
2959         }
2960
2961         if (whole && lock_task_sighand(task, &flags)) {
2962                 struct task_struct *t = task;
2963
2964                 task_io_accounting_add(&acct, &task->signal->ioac);
2965                 while_each_thread(task, t)
2966                         task_io_accounting_add(&acct, &t->ioac);
2967
2968                 unlock_task_sighand(task, &flags);
2969         }
2970         seq_printf(m,
2971                    "rchar: %llu\n"
2972                    "wchar: %llu\n"
2973                    "syscr: %llu\n"
2974                    "syscw: %llu\n"
2975                    "read_bytes: %llu\n"
2976                    "write_bytes: %llu\n"
2977                    "cancelled_write_bytes: %llu\n",
2978                    (unsigned long long)acct.rchar,
2979                    (unsigned long long)acct.wchar,
2980                    (unsigned long long)acct.syscr,
2981                    (unsigned long long)acct.syscw,
2982                    (unsigned long long)acct.read_bytes,
2983                    (unsigned long long)acct.write_bytes,
2984                    (unsigned long long)acct.cancelled_write_bytes);
2985         result = 0;
2986
2987 out_unlock:
2988         up_read(&task->signal->exec_update_lock);
2989         return result;
2990 }
2991
2992 static int proc_tid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
2993                                   struct pid *pid, struct task_struct *task)
2994 {
2995         return do_io_accounting(task, m, 0);
2996 }
2997
2998 static int proc_tgid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
2999                                    struct pid *pid, struct task_struct *task)
3000 {
3001         return do_io_accounting(task, m, 1);
3002 }
3003 #endif /* CONFIG_TASK_IO_ACCOUNTING */
3004
3005 #ifdef CONFIG_USER_NS
3006 static int proc_id_map_open(struct inode *inode, struct file *file,
3007         const struct seq_operations *seq_ops)
3008 {
3009         struct user_namespace *ns = NULL;
3010         struct task_struct *task;
3011         struct seq_file *seq;
3012         int ret = -EINVAL;
3013
3014         task = get_proc_task(inode);
3015         if (task) {
3016                 rcu_read_lock();
3017                 ns = get_user_ns(task_cred_xxx(task, user_ns));
3018                 rcu_read_unlock();
3019                 put_task_struct(task);
3020         }
3021         if (!ns)
3022                 goto err;
3023
3024         ret = seq_open(file, seq_ops);
3025         if (ret)
3026                 goto err_put_ns;
3027
3028         seq = file->private_data;
3029         seq->private = ns;
3030
3031         return 0;
3032 err_put_ns:
3033         put_user_ns(ns);
3034 err:
3035         return ret;
3036 }
3037
3038 static int proc_id_map_release(struct inode *inode, struct file *file)
3039 {
3040         struct seq_file *seq = file->private_data;
3041         struct user_namespace *ns = seq->private;
3042         put_user_ns(ns);
3043         return seq_release(inode, file);
3044 }
3045
3046 static int proc_uid_map_open(struct inode *inode, struct file *file)
3047 {
3048         return proc_id_map_open(inode, file, &proc_uid_seq_operations);
3049 }
3050
3051 static int proc_gid_map_open(struct inode *inode, struct file *file)
3052 {
3053         return proc_id_map_open(inode, file, &proc_gid_seq_operations);
3054 }
3055
3056 static int proc_projid_map_open(struct inode *inode, struct file *file)
3057 {
3058         return proc_id_map_open(inode, file, &proc_projid_seq_operations);
3059 }
3060
3061 static const struct file_operations proc_uid_map_operations = {
3062         .open           = proc_uid_map_open,
3063         .write          = proc_uid_map_write,
3064         .read           = seq_read,
3065         .llseek         = seq_lseek,
3066         .release        = proc_id_map_release,
3067 };
3068
3069 static const struct file_operations proc_gid_map_operations = {
3070         .open           = proc_gid_map_open,
3071         .write          = proc_gid_map_write,
3072         .read           = seq_read,
3073         .llseek         = seq_lseek,
3074         .release        = proc_id_map_release,
3075 };
3076
3077 static const struct file_operations proc_projid_map_operations = {
3078         .open           = proc_projid_map_open,
3079         .write          = proc_projid_map_write,
3080         .read           = seq_read,
3081         .llseek         = seq_lseek,
3082         .release        = proc_id_map_release,
3083 };
3084
3085 static int proc_setgroups_open(struct inode *inode, struct file *file)
3086 {
3087         struct user_namespace *ns = NULL;
3088         struct task_struct *task;
3089         int ret;
3090
3091         ret = -ESRCH;
3092         task = get_proc_task(inode);
3093         if (task) {
3094                 rcu_read_lock();
3095                 ns = get_user_ns(task_cred_xxx(task, user_ns));
3096                 rcu_read_unlock();
3097                 put_task_struct(task);
3098         }
3099         if (!ns)
3100                 goto err;
3101
3102         if (file->f_mode & FMODE_WRITE) {
3103                 ret = -EACCES;
3104                 if (!ns_capable(ns, CAP_SYS_ADMIN))
3105                         goto err_put_ns;
3106         }
3107
3108         ret = single_open(file, &proc_setgroups_show, ns);
3109         if (ret)
3110                 goto err_put_ns;
3111
3112         return 0;
3113 err_put_ns:
3114         put_user_ns(ns);
3115 err:
3116         return ret;
3117 }
3118
3119 static int proc_setgroups_release(struct inode *inode, struct file *file)
3120 {
3121         struct seq_file *seq = file->private_data;
3122         struct user_namespace *ns = seq->private;
3123         int ret = single_release(inode, file);
3124         put_user_ns(ns);
3125         return ret;
3126 }
3127
3128 static const struct file_operations proc_setgroups_operations = {
3129         .open           = proc_setgroups_open,
3130         .write          = proc_setgroups_write,
3131         .read           = seq_read,
3132         .llseek         = seq_lseek,
3133         .release        = proc_setgroups_release,
3134 };
3135 #endif /* CONFIG_USER_NS */
3136
3137 static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
3138                                 struct pid *pid, struct task_struct *task)
3139 {
3140         int err = lock_trace(task);
3141         if (!err) {
3142                 seq_printf(m, "%08x\n", task->personality);
3143                 unlock_trace(task);
3144         }
3145         return err;
3146 }
3147
3148 #ifdef CONFIG_LIVEPATCH
3149 static int proc_pid_patch_state(struct seq_file *m, struct pid_namespace *ns,
3150                                 struct pid *pid, struct task_struct *task)
3151 {
3152         seq_printf(m, "%d\n", task->patch_state);
3153         return 0;
3154 }
3155 #endif /* CONFIG_LIVEPATCH */
3156
3157 #ifdef CONFIG_STACKLEAK_METRICS
3158 static int proc_stack_depth(struct seq_file *m, struct pid_namespace *ns,
3159                                 struct pid *pid, struct task_struct *task)
3160 {
3161         unsigned long prev_depth = THREAD_SIZE -
3162                                 (task->prev_lowest_stack & (THREAD_SIZE - 1));
3163         unsigned long depth = THREAD_SIZE -
3164                                 (task->lowest_stack & (THREAD_SIZE - 1));
3165
3166         seq_printf(m, "previous stack depth: %lu\nstack depth: %lu\n",
3167                                                         prev_depth, depth);
3168         return 0;
3169 }
3170 #endif /* CONFIG_STACKLEAK_METRICS */
3171
3172 /*
3173  * Thread groups
3174  */
3175 static const struct file_operations proc_task_operations;
3176 static const struct inode_operations proc_task_inode_operations;
3177
3178 static const struct pid_entry tgid_base_stuff[] = {
3179         DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
3180         DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3181         DIR("map_files",  S_IRUSR|S_IXUSR, proc_map_files_inode_operations, proc_map_files_operations),
3182         DIR("fdinfo",     S_IRUGO|S_IXUGO, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3183         DIR("ns",         S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3184 #ifdef CONFIG_NET
3185         DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
3186 #endif
3187         REG("environ",    S_IRUSR, proc_environ_operations),
3188         REG("auxv",       S_IRUSR, proc_auxv_operations),
3189         ONE("status",     S_IRUGO, proc_pid_status),
3190         ONE("personality", S_IRUSR, proc_pid_personality),
3191         ONE("limits",     S_IRUGO, proc_pid_limits),
3192 #ifdef CONFIG_SCHED_DEBUG
3193         REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3194 #endif
3195 #ifdef CONFIG_SCHED_AUTOGROUP
3196         REG("autogroup",  S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations),
3197 #endif
3198 #ifdef CONFIG_TIME_NS
3199         REG("timens_offsets",  S_IRUGO|S_IWUSR, proc_timens_offsets_operations),
3200 #endif
3201         REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
3202 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3203         ONE("syscall",    S_IRUSR, proc_pid_syscall),
3204 #endif
3205         REG("cmdline",    S_IRUGO, proc_pid_cmdline_ops),
3206         ONE("stat",       S_IRUGO, proc_tgid_stat),
3207         ONE("statm",      S_IRUGO, proc_pid_statm),
3208         REG("maps",       S_IRUGO, proc_pid_maps_operations),
3209 #ifdef CONFIG_NUMA
3210         REG("numa_maps",  S_IRUGO, proc_pid_numa_maps_operations),
3211 #endif
3212         REG("mem",        S_IRUSR|S_IWUSR, proc_mem_operations),
3213         LNK("cwd",        proc_cwd_link),
3214         LNK("root",       proc_root_link),
3215         LNK("exe",        proc_exe_link),
3216         REG("mounts",     S_IRUGO, proc_mounts_operations),
3217         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3218         REG("mountstats", S_IRUSR, proc_mountstats_operations),
3219 #ifdef CONFIG_PROC_PAGE_MONITOR
3220         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3221         REG("smaps",      S_IRUGO, proc_pid_smaps_operations),
3222         REG("smaps_rollup", S_IRUGO, proc_pid_smaps_rollup_operations),
3223         REG("pagemap",    S_IRUSR, proc_pagemap_operations),
3224 #endif
3225 #ifdef CONFIG_SECURITY
3226         DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3227 #endif
3228 #ifdef CONFIG_KALLSYMS
3229         ONE("wchan",      S_IRUGO, proc_pid_wchan),
3230 #endif
3231 #ifdef CONFIG_STACKTRACE
3232         ONE("stack",      S_IRUSR, proc_pid_stack),
3233 #endif
3234 #ifdef CONFIG_SCHED_INFO
3235         ONE("schedstat",  S_IRUGO, proc_pid_schedstat),
3236 #endif
3237 #ifdef CONFIG_LATENCYTOP
3238         REG("latency",  S_IRUGO, proc_lstats_operations),
3239 #endif
3240 #ifdef CONFIG_PROC_PID_CPUSET
3241         ONE("cpuset",     S_IRUGO, proc_cpuset_show),
3242 #endif
3243 #ifdef CONFIG_CGROUPS
3244         ONE("cgroup",  S_IRUGO, proc_cgroup_show),
3245 #endif
3246 #ifdef CONFIG_PROC_CPU_RESCTRL
3247         ONE("cpu_resctrl_groups", S_IRUGO, proc_resctrl_show),
3248 #endif
3249         ONE("oom_score",  S_IRUGO, proc_oom_score),
3250         REG("oom_adj",    S_IRUGO|S_IWUSR, proc_oom_adj_operations),
3251         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3252 #ifdef CONFIG_AUDIT
3253         REG("loginuid",   S_IWUSR|S_IRUGO, proc_loginuid_operations),
3254         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3255 #endif
3256 #ifdef CONFIG_FAULT_INJECTION
3257         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3258         REG("fail-nth", 0644, proc_fail_nth_operations),
3259 #endif
3260 #ifdef CONFIG_ELF_CORE
3261         REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
3262 #endif
3263 #ifdef CONFIG_TASK_IO_ACCOUNTING
3264         ONE("io",       S_IRUSR, proc_tgid_io_accounting),
3265 #endif
3266 #ifdef CONFIG_USER_NS
3267         REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
3268         REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
3269         REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
3270         REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
3271 #endif
3272 #if defined(CONFIG_CHECKPOINT_RESTORE) && defined(CONFIG_POSIX_TIMERS)
3273         REG("timers",     S_IRUGO, proc_timers_operations),
3274 #endif
3275         REG("timerslack_ns", S_IRUGO|S_IWUGO, proc_pid_set_timerslack_ns_operations),
3276 #ifdef CONFIG_LIVEPATCH
3277         ONE("patch_state",  S_IRUSR, proc_pid_patch_state),
3278 #endif
3279 #ifdef CONFIG_STACKLEAK_METRICS
3280         ONE("stack_depth", S_IRUGO, proc_stack_depth),
3281 #endif
3282 #ifdef CONFIG_PROC_PID_ARCH_STATUS
3283         ONE("arch_status", S_IRUGO, proc_pid_arch_status),
3284 #endif
3285 #ifdef CONFIG_SECCOMP_CACHE_DEBUG
3286         ONE("seccomp_cache", S_IRUSR, proc_pid_seccomp_cache),
3287 #endif
3288 };
3289
3290 static int proc_tgid_base_readdir(struct file *file, struct dir_context *ctx)
3291 {
3292         return proc_pident_readdir(file, ctx,
3293                                    tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
3294 }
3295
3296 static const struct file_operations proc_tgid_base_operations = {
3297         .read           = generic_read_dir,
3298         .iterate_shared = proc_tgid_base_readdir,
3299         .llseek         = generic_file_llseek,
3300 };
3301
3302 struct pid *tgid_pidfd_to_pid(const struct file *file)
3303 {
3304         if (file->f_op != &proc_tgid_base_operations)
3305                 return ERR_PTR(-EBADF);
3306
3307         return proc_pid(file_inode(file));
3308 }
3309
3310 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
3311 {
3312         return proc_pident_lookup(dir, dentry,
3313                                   tgid_base_stuff,
3314                                   tgid_base_stuff + ARRAY_SIZE(tgid_base_stuff));
3315 }
3316
3317 static const struct inode_operations proc_tgid_base_inode_operations = {
3318         .lookup         = proc_tgid_base_lookup,
3319         .getattr        = pid_getattr,
3320         .setattr        = proc_setattr,
3321         .permission     = proc_pid_permission,
3322 };
3323
3324 /**
3325  * proc_flush_pid -  Remove dcache entries for @pid from the /proc dcache.
3326  * @pid: pid that should be flushed.
3327  *
3328  * This function walks a list of inodes (that belong to any proc
3329  * filesystem) that are attached to the pid and flushes them from
3330  * the dentry cache.
3331  *
3332  * It is safe and reasonable to cache /proc entries for a task until
3333  * that task exits.  After that they just clog up the dcache with
3334  * useless entries, possibly causing useful dcache entries to be
3335  * flushed instead.  This routine is provided to flush those useless
3336  * dcache entries when a process is reaped.
3337  *
3338  * NOTE: This routine is just an optimization so it does not guarantee
3339  *       that no dcache entries will exist after a process is reaped
3340  *       it just makes it very unlikely that any will persist.
3341  */
3342
3343 void proc_flush_pid(struct pid *pid)
3344 {
3345         proc_invalidate_siblings_dcache(&pid->inodes, &pid->lock);
3346 }
3347
3348 static struct dentry *proc_pid_instantiate(struct dentry * dentry,
3349                                    struct task_struct *task, const void *ptr)
3350 {
3351         struct inode *inode;
3352
3353         inode = proc_pid_make_inode(dentry->d_sb, task, S_IFDIR | S_IRUGO | S_IXUGO);
3354         if (!inode)
3355                 return ERR_PTR(-ENOENT);
3356
3357         inode->i_op = &proc_tgid_base_inode_operations;
3358         inode->i_fop = &proc_tgid_base_operations;
3359         inode->i_flags|=S_IMMUTABLE;
3360
3361         set_nlink(inode, nlink_tgid);
3362         pid_update_inode(task, inode);
3363
3364         d_set_d_op(dentry, &pid_dentry_operations);
3365         return d_splice_alias(inode, dentry);
3366 }
3367
3368 struct dentry *proc_pid_lookup(struct dentry *dentry, unsigned int flags)
3369 {
3370         struct task_struct *task;
3371         unsigned tgid;
3372         struct proc_fs_info *fs_info;
3373         struct pid_namespace *ns;
3374         struct dentry *result = ERR_PTR(-ENOENT);
3375
3376         tgid = name_to_int(&dentry->d_name);
3377         if (tgid == ~0U)
3378                 goto out;
3379
3380         fs_info = proc_sb_info(dentry->d_sb);
3381         ns = fs_info->pid_ns;
3382         rcu_read_lock();
3383         task = find_task_by_pid_ns(tgid, ns);
3384         if (task)
3385                 get_task_struct(task);
3386         rcu_read_unlock();
3387         if (!task)
3388                 goto out;
3389
3390         /* Limit procfs to only ptraceable tasks */
3391         if (fs_info->hide_pid == HIDEPID_NOT_PTRACEABLE) {
3392                 if (!has_pid_permissions(fs_info, task, HIDEPID_NO_ACCESS))
3393                         goto out_put_task;
3394         }
3395
3396         result = proc_pid_instantiate(dentry, task, NULL);
3397 out_put_task:
3398         put_task_struct(task);
3399 out:
3400         return result;
3401 }
3402
3403 /*
3404  * Find the first task with tgid >= tgid
3405  *
3406  */
3407 struct tgid_iter {
3408         unsigned int tgid;
3409         struct task_struct *task;
3410 };
3411 static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
3412 {
3413         struct pid *pid;
3414
3415         if (iter.task)
3416                 put_task_struct(iter.task);
3417         rcu_read_lock();
3418 retry:
3419         iter.task = NULL;
3420         pid = find_ge_pid(iter.tgid, ns);
3421         if (pid) {
3422                 iter.tgid = pid_nr_ns(pid, ns);
3423                 iter.task = pid_task(pid, PIDTYPE_TGID);
3424                 if (!iter.task) {
3425                         iter.tgid += 1;
3426                         goto retry;
3427                 }
3428                 get_task_struct(iter.task);
3429         }
3430         rcu_read_unlock();
3431         return iter;
3432 }
3433
3434 #define TGID_OFFSET (FIRST_PROCESS_ENTRY + 2)
3435
3436 /* for the /proc/ directory itself, after non-process stuff has been done */
3437 int proc_pid_readdir(struct file *file, struct dir_context *ctx)
3438 {
3439         struct tgid_iter iter;
3440         struct proc_fs_info *fs_info = proc_sb_info(file_inode(file)->i_sb);
3441         struct pid_namespace *ns = proc_pid_ns(file_inode(file)->i_sb);
3442         loff_t pos = ctx->pos;
3443
3444         if (pos >= PID_MAX_LIMIT + TGID_OFFSET)
3445                 return 0;
3446
3447         if (pos == TGID_OFFSET - 2) {
3448                 struct inode *inode = d_inode(fs_info->proc_self);
3449                 if (!dir_emit(ctx, "self", 4, inode->i_ino, DT_LNK))
3450                         return 0;
3451                 ctx->pos = pos = pos + 1;
3452         }
3453         if (pos == TGID_OFFSET - 1) {
3454                 struct inode *inode = d_inode(fs_info->proc_thread_self);
3455                 if (!dir_emit(ctx, "thread-self", 11, inode->i_ino, DT_LNK))
3456                         return 0;
3457                 ctx->pos = pos = pos + 1;
3458         }
3459         iter.tgid = pos - TGID_OFFSET;
3460         iter.task = NULL;
3461         for (iter = next_tgid(ns, iter);
3462              iter.task;
3463              iter.tgid += 1, iter = next_tgid(ns, iter)) {
3464                 char name[10 + 1];
3465                 unsigned int len;
3466
3467                 cond_resched();
3468                 if (!has_pid_permissions(fs_info, iter.task, HIDEPID_INVISIBLE))
3469                         continue;
3470
3471                 len = snprintf(name, sizeof(name), "%u", iter.tgid);
3472                 ctx->pos = iter.tgid + TGID_OFFSET;
3473                 if (!proc_fill_cache(file, ctx, name, len,
3474                                      proc_pid_instantiate, iter.task, NULL)) {
3475                         put_task_struct(iter.task);
3476                         return 0;
3477                 }
3478         }
3479         ctx->pos = PID_MAX_LIMIT + TGID_OFFSET;
3480         return 0;
3481 }
3482
3483 /*
3484  * proc_tid_comm_permission is a special permission function exclusively
3485  * used for the node /proc/<pid>/task/<tid>/comm.
3486  * It bypasses generic permission checks in the case where a task of the same
3487  * task group attempts to access the node.
3488  * The rationale behind this is that glibc and bionic access this node for
3489  * cross thread naming (pthread_set/getname_np(!self)). However, if
3490  * PR_SET_DUMPABLE gets set to 0 this node among others becomes uid=0 gid=0,
3491  * which locks out the cross thread naming implementation.
3492  * This function makes sure that the node is always accessible for members of
3493  * same thread group.
3494  */
3495 static int proc_tid_comm_permission(struct user_namespace *mnt_userns,
3496                                     struct inode *inode, int mask)
3497 {
3498         bool is_same_tgroup;
3499         struct task_struct *task;
3500
3501         task = get_proc_task(inode);
3502         if (!task)
3503                 return -ESRCH;
3504         is_same_tgroup = same_thread_group(current, task);
3505         put_task_struct(task);
3506
3507         if (likely(is_same_tgroup && !(mask & MAY_EXEC))) {
3508                 /* This file (/proc/<pid>/task/<tid>/comm) can always be
3509                  * read or written by the members of the corresponding
3510                  * thread group.
3511                  */
3512                 return 0;
3513         }
3514
3515         return generic_permission(&init_user_ns, inode, mask);
3516 }
3517
3518 static const struct inode_operations proc_tid_comm_inode_operations = {
3519                 .permission = proc_tid_comm_permission,
3520 };
3521
3522 /*
3523  * Tasks
3524  */
3525 static const struct pid_entry tid_base_stuff[] = {
3526         DIR("fd",        S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3527         DIR("fdinfo",    S_IRUGO|S_IXUGO, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3528         DIR("ns",        S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3529 #ifdef CONFIG_NET
3530         DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
3531 #endif
3532         REG("environ",   S_IRUSR, proc_environ_operations),
3533         REG("auxv",      S_IRUSR, proc_auxv_operations),
3534         ONE("status",    S_IRUGO, proc_pid_status),
3535         ONE("personality", S_IRUSR, proc_pid_personality),
3536         ONE("limits",    S_IRUGO, proc_pid_limits),
3537 #ifdef CONFIG_SCHED_DEBUG
3538         REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3539 #endif
3540         NOD("comm",      S_IFREG|S_IRUGO|S_IWUSR,
3541                          &proc_tid_comm_inode_operations,
3542                          &proc_pid_set_comm_operations, {}),
3543 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3544         ONE("syscall",   S_IRUSR, proc_pid_syscall),
3545 #endif
3546         REG("cmdline",   S_IRUGO, proc_pid_cmdline_ops),
3547         ONE("stat",      S_IRUGO, proc_tid_stat),
3548         ONE("statm",     S_IRUGO, proc_pid_statm),
3549         REG("maps",      S_IRUGO, proc_pid_maps_operations),
3550 #ifdef CONFIG_PROC_CHILDREN
3551         REG("children",  S_IRUGO, proc_tid_children_operations),
3552 #endif
3553 #ifdef CONFIG_NUMA
3554         REG("numa_maps", S_IRUGO, proc_pid_numa_maps_operations),
3555 #endif
3556         REG("mem",       S_IRUSR|S_IWUSR, proc_mem_operations),
3557         LNK("cwd",       proc_cwd_link),
3558         LNK("root",      proc_root_link),
3559         LNK("exe",       proc_exe_link),
3560         REG("mounts",    S_IRUGO, proc_mounts_operations),
3561         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3562 #ifdef CONFIG_PROC_PAGE_MONITOR
3563         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3564         REG("smaps",     S_IRUGO, proc_pid_smaps_operations),
3565         REG("smaps_rollup", S_IRUGO, proc_pid_smaps_rollup_operations),
3566         REG("pagemap",    S_IRUSR, proc_pagemap_operations),
3567 #endif
3568 #ifdef CONFIG_SECURITY
3569         DIR("attr",      S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3570 #endif
3571 #ifdef CONFIG_KALLSYMS
3572         ONE("wchan",     S_IRUGO, proc_pid_wchan),
3573 #endif
3574 #ifdef CONFIG_STACKTRACE
3575         ONE("stack",      S_IRUSR, proc_pid_stack),
3576 #endif
3577 #ifdef CONFIG_SCHED_INFO
3578         ONE("schedstat", S_IRUGO, proc_pid_schedstat),
3579 #endif
3580 #ifdef CONFIG_LATENCYTOP
3581         REG("latency",  S_IRUGO, proc_lstats_operations),
3582 #endif
3583 #ifdef CONFIG_PROC_PID_CPUSET
3584         ONE("cpuset",    S_IRUGO, proc_cpuset_show),
3585 #endif
3586 #ifdef CONFIG_CGROUPS
3587         ONE("cgroup",  S_IRUGO, proc_cgroup_show),
3588 #endif
3589 #ifdef CONFIG_PROC_CPU_RESCTRL
3590         ONE("cpu_resctrl_groups", S_IRUGO, proc_resctrl_show),
3591 #endif
3592         ONE("oom_score", S_IRUGO, proc_oom_score),
3593         REG("oom_adj",   S_IRUGO|S_IWUSR, proc_oom_adj_operations),
3594         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3595 #ifdef CONFIG_AUDIT
3596         REG("loginuid",  S_IWUSR|S_IRUGO, proc_loginuid_operations),
3597         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3598 #endif
3599 #ifdef CONFIG_FAULT_INJECTION
3600         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3601         REG("fail-nth", 0644, proc_fail_nth_operations),
3602 #endif
3603 #ifdef CONFIG_TASK_IO_ACCOUNTING
3604         ONE("io",       S_IRUSR, proc_tid_io_accounting),
3605 #endif
3606 #ifdef CONFIG_USER_NS
3607         REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
3608         REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
3609         REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
3610         REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
3611 #endif
3612 #ifdef CONFIG_LIVEPATCH
3613         ONE("patch_state",  S_IRUSR, proc_pid_patch_state),
3614 #endif
3615 #ifdef CONFIG_PROC_PID_ARCH_STATUS
3616         ONE("arch_status", S_IRUGO, proc_pid_arch_status),
3617 #endif
3618 #ifdef CONFIG_SECCOMP_CACHE_DEBUG
3619         ONE("seccomp_cache", S_IRUSR, proc_pid_seccomp_cache),
3620 #endif
3621 };
3622
3623 static int proc_tid_base_readdir(struct file *file, struct dir_context *ctx)
3624 {
3625         return proc_pident_readdir(file, ctx,
3626                                    tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3627 }
3628
3629 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
3630 {
3631         return proc_pident_lookup(dir, dentry,
3632                                   tid_base_stuff,
3633                                   tid_base_stuff + ARRAY_SIZE(tid_base_stuff));
3634 }
3635
3636 static const struct file_operations proc_tid_base_operations = {
3637         .read           = generic_read_dir,
3638         .iterate_shared = proc_tid_base_readdir,
3639         .llseek         = generic_file_llseek,
3640 };
3641
3642 static const struct inode_operations proc_tid_base_inode_operations = {
3643         .lookup         = proc_tid_base_lookup,
3644         .getattr        = pid_getattr,
3645         .setattr        = proc_setattr,
3646 };
3647
3648 static struct dentry *proc_task_instantiate(struct dentry *dentry,
3649         struct task_struct *task, const void *ptr)
3650 {
3651         struct inode *inode;
3652         inode = proc_pid_make_inode(dentry->d_sb, task, S_IFDIR | S_IRUGO | S_IXUGO);
3653         if (!inode)
3654                 return ERR_PTR(-ENOENT);
3655
3656         inode->i_op = &proc_tid_base_inode_operations;
3657         inode->i_fop = &proc_tid_base_operations;
3658         inode->i_flags |= S_IMMUTABLE;
3659
3660         set_nlink(inode, nlink_tid);
3661         pid_update_inode(task, inode);
3662
3663         d_set_d_op(dentry, &pid_dentry_operations);
3664         return d_splice_alias(inode, dentry);
3665 }
3666
3667 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
3668 {
3669         struct task_struct *task;
3670         struct task_struct *leader = get_proc_task(dir);
3671         unsigned tid;
3672         struct proc_fs_info *fs_info;
3673         struct pid_namespace *ns;
3674         struct dentry *result = ERR_PTR(-ENOENT);
3675
3676         if (!leader)
3677                 goto out_no_task;
3678
3679         tid = name_to_int(&dentry->d_name);
3680         if (tid == ~0U)
3681                 goto out;
3682
3683         fs_info = proc_sb_info(dentry->d_sb);
3684         ns = fs_info->pid_ns;
3685         rcu_read_lock();
3686         task = find_task_by_pid_ns(tid, ns);
3687         if (task)
3688                 get_task_struct(task);
3689         rcu_read_unlock();
3690         if (!task)
3691                 goto out;
3692         if (!same_thread_group(leader, task))
3693                 goto out_drop_task;
3694
3695         result = proc_task_instantiate(dentry, task, NULL);
3696 out_drop_task:
3697         put_task_struct(task);
3698 out:
3699         put_task_struct(leader);
3700 out_no_task:
3701         return result;
3702 }
3703
3704 /*
3705  * Find the first tid of a thread group to return to user space.
3706  *
3707  * Usually this is just the thread group leader, but if the users
3708  * buffer was too small or there was a seek into the middle of the
3709  * directory we have more work todo.
3710  *
3711  * In the case of a short read we start with find_task_by_pid.
3712  *
3713  * In the case of a seek we start with the leader and walk nr
3714  * threads past it.
3715  */
3716 static struct task_struct *first_tid(struct pid *pid, int tid, loff_t f_pos,
3717                                         struct pid_namespace *ns)
3718 {
3719         struct task_struct *pos, *task;
3720         unsigned long nr = f_pos;
3721
3722         if (nr != f_pos)        /* 32bit overflow? */
3723                 return NULL;
3724
3725         rcu_read_lock();
3726         task = pid_task(pid, PIDTYPE_PID);
3727         if (!task)
3728                 goto fail;
3729
3730         /* Attempt to start with the tid of a thread */
3731         if (tid && nr) {
3732                 pos = find_task_by_pid_ns(tid, ns);
3733                 if (pos && same_thread_group(pos, task))
3734                         goto found;
3735         }
3736
3737         /* If nr exceeds the number of threads there is nothing todo */
3738         if (nr >= get_nr_threads(task))
3739                 goto fail;
3740
3741         /* If we haven't found our starting place yet start
3742          * with the leader and walk nr threads forward.
3743          */
3744         pos = task = task->group_leader;
3745         do {
3746                 if (!nr--)
3747                         goto found;
3748         } while_each_thread(task, pos);
3749 fail:
3750         pos = NULL;
3751         goto out;
3752 found:
3753         get_task_struct(pos);
3754 out:
3755         rcu_read_unlock();
3756         return pos;
3757 }
3758
3759 /*
3760  * Find the next thread in the thread list.
3761  * Return NULL if there is an error or no next thread.
3762  *
3763  * The reference to the input task_struct is released.
3764  */
3765 static struct task_struct *next_tid(struct task_struct *start)
3766 {
3767         struct task_struct *pos = NULL;
3768         rcu_read_lock();
3769         if (pid_alive(start)) {
3770                 pos = next_thread(start);
3771                 if (thread_group_leader(pos))
3772                         pos = NULL;
3773                 else
3774                         get_task_struct(pos);
3775         }
3776         rcu_read_unlock();
3777         put_task_struct(start);
3778         return pos;
3779 }
3780
3781 /* for the /proc/TGID/task/ directories */
3782 static int proc_task_readdir(struct file *file, struct dir_context *ctx)
3783 {
3784         struct inode *inode = file_inode(file);
3785         struct task_struct *task;
3786         struct pid_namespace *ns;
3787         int tid;
3788
3789         if (proc_inode_is_dead(inode))
3790                 return -ENOENT;
3791
3792         if (!dir_emit_dots(file, ctx))
3793                 return 0;
3794
3795         /* f_version caches the tgid value that the last readdir call couldn't
3796          * return. lseek aka telldir automagically resets f_version to 0.
3797          */
3798         ns = proc_pid_ns(inode->i_sb);
3799         tid = (int)file->f_version;
3800         file->f_version = 0;
3801         for (task = first_tid(proc_pid(inode), tid, ctx->pos - 2, ns);
3802              task;
3803              task = next_tid(task), ctx->pos++) {
3804                 char name[10 + 1];
3805                 unsigned int len;
3806
3807                 tid = task_pid_nr_ns(task, ns);
3808                 if (!tid)
3809                         continue;       /* The task has just exited. */
3810                 len = snprintf(name, sizeof(name), "%u", tid);
3811                 if (!proc_fill_cache(file, ctx, name, len,
3812                                 proc_task_instantiate, task, NULL)) {
3813                         /* returning this tgid failed, save it as the first
3814                          * pid for the next readir call */
3815                         file->f_version = (u64)tid;
3816                         put_task_struct(task);
3817                         break;
3818                 }
3819         }
3820
3821         return 0;
3822 }
3823
3824 static int proc_task_getattr(struct user_namespace *mnt_userns,
3825                              const struct path *path, struct kstat *stat,
3826                              u32 request_mask, unsigned int query_flags)
3827 {
3828         struct inode *inode = d_inode(path->dentry);
3829         struct task_struct *p = get_proc_task(inode);
3830         generic_fillattr(&init_user_ns, inode, stat);
3831
3832         if (p) {
3833                 stat->nlink += get_nr_threads(p);
3834                 put_task_struct(p);
3835         }
3836
3837         return 0;
3838 }
3839
3840 static const struct inode_operations proc_task_inode_operations = {
3841         .lookup         = proc_task_lookup,
3842         .getattr        = proc_task_getattr,
3843         .setattr        = proc_setattr,
3844         .permission     = proc_pid_permission,
3845 };
3846
3847 static const struct file_operations proc_task_operations = {
3848         .read           = generic_read_dir,
3849         .iterate_shared = proc_task_readdir,
3850         .llseek         = generic_file_llseek,
3851 };
3852
3853 void __init set_proc_pid_nlink(void)
3854 {
3855         nlink_tid = pid_entry_nlink(tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3856         nlink_tgid = pid_entry_nlink(tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
3857 }