kernel/seccomp.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * linux/kernel/seccomp.c
   4  *
   5  * Copyright 2004-2005  Andrea Arcangeli <andrea@cpushare.com>
   6  *
   7  * Copyright (C) 2012 Google, Inc.
   8  * Will Drewry <wad@chromium.org>
   9  *
  10  * This defines a simple but solid secure-computing facility.
  11  *
  12  * Mode 1 uses a fixed list of allowed system calls.
  13  * Mode 2 allows user-defined system call filters in the form
  14  *        of Berkeley Packet Filters/Linux Socket Filters.
  15  */
  16
  17 #include <linux/refcount.h>
  18 #include <linux/audit.h>
  19 #include <linux/compat.h>
  20 #include <linux/coredump.h>
  21 #include <linux/kmemleak.h>
  22 #include <linux/nospec.h>
  23 #include <linux/prctl.h>
  24 #include <linux/sched.h>
  25 #include <linux/sched/task_stack.h>
  26 #include <linux/seccomp.h>
  27 #include <linux/slab.h>
  28 #include <linux/syscalls.h>
  29 #include <linux/sysctl.h>
  30
  31 #ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER
  32 #include <asm/syscall.h>
  33 #endif
  34
  35 #ifdef CONFIG_SECCOMP_FILTER
  36 #include <linux/filter.h>
  37 #include <linux/pid.h>
  38 #include <linux/ptrace.h>
  39 #include <linux/security.h>
  40 #include <linux/tracehook.h>
  41 #include <linux/uaccess.h>
  42
  43 /**
  44  * struct seccomp_filter - container for seccomp BPF programs
  45  *
  46  * @usage: reference count to manage the object lifetime.
  47  *         get/put helpers should be used when accessing an instance
  48  *         outside of a lifetime-guarded section.  In general, this
  49  *         is only needed for handling filters shared across tasks.
  50  * @log: true if all actions except for SECCOMP_RET_ALLOW should be logged
  51  * @prev: points to a previously installed, or inherited, filter
  52  * @prog: the BPF program to evaluate
  53  *
  54  * seccomp_filter objects are organized in a tree linked via the @prev
  55  * pointer.  For any task, it appears to be a singly-linked list starting
  56  * with current->seccomp.filter, the most recently attached or inherited filter.
  57  * However, multiple filters may share a @prev node, by way of fork(), which
  58  * results in a unidirectional tree existing in memory.  This is similar to
  59  * how namespaces work.
  60  *
  61  * seccomp_filter objects should never be modified after being attached
  62  * to a task_struct (other than @usage).
  63  */
  64 struct seccomp_filter {
  65         refcount_t usage;
  66         bool log;
  67         struct seccomp_filter *prev;
  68         struct bpf_prog *prog;
  69 };
  70
  71 /* Limit any path through the tree to 256KB worth of instructions. */
  72 #define MAX_INSNS_PER_PATH ((1 << 18) / sizeof(struct sock_filter))
  73
  74 /*
  75  * Endianness is explicitly ignored and left for BPF program authors to manage
  76  * as per the specific architecture.
  77  */
  78 static void populate_seccomp_data(struct seccomp_data *sd)
  79 {
  80         struct task_struct *task = current;
  81         struct pt_regs *regs = task_pt_regs(task);
  82         unsigned long args[6];
  83
  84         sd->nr = syscall_get_nr(task, regs);
  85         sd->arch = syscall_get_arch();
  86         syscall_get_arguments(task, regs, 0, 6, args);
  87         sd->args[0] = args[0];
  88         sd->args[1] = args[1];
  89         sd->args[2] = args[2];
  90         sd->args[3] = args[3];
  91         sd->args[4] = args[4];
  92         sd->args[5] = args[5];
  93         sd->instruction_pointer = KSTK_EIP(task);
  94 }
  95
  96 /**
  97  *      seccomp_check_filter - verify seccomp filter code
  98  *      @filter: filter to verify
  99  *      @flen: length of filter
 100  *
 101  * Takes a previously checked filter (by bpf_check_classic) and
 102  * redirects all filter code that loads struct sk_buff data
 103  * and related data through seccomp_bpf_load.  It also
 104  * enforces length and alignment checking of those loads.
 105  *
 106  * Returns 0 if the rule set is legal or -EINVAL if not.
 107  */
 108 static int seccomp_check_filter(struct sock_filter *filter, unsigned int flen)
 109 {
 110         int pc;
 111         for (pc = 0; pc < flen; pc++) {
 112                 struct sock_filter *ftest = &filter[pc];
 113                 u16 code = ftest->code;
 114                 u32 k = ftest->k;
 115
 116                 switch (code) {
 117                 case BPF_LD | BPF_W | BPF_ABS:
 118                         ftest->code = BPF_LDX | BPF_W | BPF_ABS;
 119                         /* 32-bit aligned and not out of bounds. */
 120                         if (k >= sizeof(struct seccomp_data) || k & 3)
 121                                 return -EINVAL;
 122                         continue;
 123                 case BPF_LD | BPF_W | BPF_LEN:
 124                         ftest->code = BPF_LD | BPF_IMM;
 125                         ftest->k = sizeof(struct seccomp_data);
 126                         continue;
 127                 case BPF_LDX | BPF_W | BPF_LEN:
 128                         ftest->code = BPF_LDX | BPF_IMM;
 129                         ftest->k = sizeof(struct seccomp_data);
 130                         continue;
 131                 /* Explicitly include allowed calls. */
 132                 case BPF_RET | BPF_K:
 133                 case BPF_RET | BPF_A:
 134                 case BPF_ALU | BPF_ADD | BPF_K:
 135                 case BPF_ALU | BPF_ADD | BPF_X:
 136                 case BPF_ALU | BPF_SUB | BPF_K:
 137                 case BPF_ALU | BPF_SUB | BPF_X:
 138                 case BPF_ALU | BPF_MUL | BPF_K:
 139                 case BPF_ALU | BPF_MUL | BPF_X:
 140                 case BPF_ALU | BPF_DIV | BPF_K:
 141                 case BPF_ALU | BPF_DIV | BPF_X:
 142                 case BPF_ALU | BPF_AND | BPF_K:
 143                 case BPF_ALU | BPF_AND | BPF_X:
 144                 case BPF_ALU | BPF_OR | BPF_K:
 145                 case BPF_ALU | BPF_OR | BPF_X:
 146                 case BPF_ALU | BPF_XOR | BPF_K:
 147                 case BPF_ALU | BPF_XOR | BPF_X:
 148                 case BPF_ALU | BPF_LSH | BPF_K:
 149                 case BPF_ALU | BPF_LSH | BPF_X:
 150                 case BPF_ALU | BPF_RSH | BPF_K:
 151                 case BPF_ALU | BPF_RSH | BPF_X:
 152                 case BPF_ALU | BPF_NEG:
 153                 case BPF_LD | BPF_IMM:
 154                 case BPF_LDX | BPF_IMM:
 155                 case BPF_MISC | BPF_TAX:
 156                 case BPF_MISC | BPF_TXA:
 157                 case BPF_LD | BPF_MEM:
 158                 case BPF_LDX | BPF_MEM:
 159                 case BPF_ST:
 160                 case BPF_STX:
 161                 case BPF_JMP | BPF_JA:
 162                 case BPF_JMP | BPF_JEQ | BPF_K:
 163                 case BPF_JMP | BPF_JEQ | BPF_X:
 164                 case BPF_JMP | BPF_JGE | BPF_K:
 165                 case BPF_JMP | BPF_JGE | BPF_X:
 166                 case BPF_JMP | BPF_JGT | BPF_K:
 167                 case BPF_JMP | BPF_JGT | BPF_X:
 168                 case BPF_JMP | BPF_JSET | BPF_K:
 169                 case BPF_JMP | BPF_JSET | BPF_X:
 170                         continue;
 171                 default:
 172                         return -EINVAL;
 173                 }
 174         }
 175         return 0;
 176 }
 177
 178 /**
 179  * seccomp_run_filters - evaluates all seccomp filters against @sd
 180  * @sd: optional seccomp data to be passed to filters
 181  * @match: stores struct seccomp_filter that resulted in the return value,
 182  *         unless filter returned SECCOMP_RET_ALLOW, in which case it will
 183  *         be unchanged.
 184  *
 185  * Returns valid seccomp BPF response codes.
 186  */
 187 #define ACTION_ONLY(ret) ((s32)((ret) & (SECCOMP_RET_ACTION_FULL)))
 188 static u32 seccomp_run_filters(const struct seccomp_data *sd,
 189                                struct seccomp_filter **match)
 190 {
 191         struct seccomp_data sd_local;
 192         u32 ret = SECCOMP_RET_ALLOW;
 193         /* Make sure cross-thread synced filter points somewhere sane. */
 194         struct seccomp_filter *f =
 195                         READ_ONCE(current->seccomp.filter);
 196
 197         /* Ensure unexpected behavior doesn't result in failing open. */
 198         if (unlikely(WARN_ON(f == NULL)))
 199                 return SECCOMP_RET_KILL_PROCESS;
 200
 201         if (!sd) {
 202                 populate_seccomp_data(&sd_local);
 203                 sd = &sd_local;
 204         }
 205
 206         /*
 207          * All filters in the list are evaluated and the lowest BPF return
 208          * value always takes priority (ignoring the DATA).
 209          */
 210         for (; f; f = f->prev) {
 211                 u32 cur_ret = BPF_PROG_RUN(f->prog, sd);
 212
 213                 if (ACTION_ONLY(cur_ret) < ACTION_ONLY(ret)) {
 214                         ret = cur_ret;
 215                         *match = f;
 216                 }
 217         }
 218         return ret;
 219 }
 220 #endif /* CONFIG_SECCOMP_FILTER */
 221
 222 static inline bool seccomp_may_assign_mode(unsigned long seccomp_mode)
 223 {
 224         assert_spin_locked(&current->sighand->siglock);
 225
 226         if (current->seccomp.mode && current->seccomp.mode != seccomp_mode)
 227                 return false;
 228
 229         return true;
 230 }
 231
 232 void __weak arch_seccomp_spec_mitigate(struct task_struct *task) { }
 233
 234 static inline void seccomp_assign_mode(struct task_struct *task,
 235                                        unsigned long seccomp_mode,
 236                                        unsigned long flags)
 237 {
 238         assert_spin_locked(&task->sighand->siglock);
 239
 240         task->seccomp.mode = seccomp_mode;
 241         /*
 242          * Make sure TIF_SECCOMP cannot be set before the mode (and
 243          * filter) is set.
 244          */
 245         smp_mb__before_atomic();
 246         /* Assume default seccomp processes want spec flaw mitigation. */
 247         if ((flags & SECCOMP_FILTER_FLAG_SPEC_ALLOW) == 0)
 248                 arch_seccomp_spec_mitigate(task);
 249         set_tsk_thread_flag(task, TIF_SECCOMP);
 250 }
 251
 252 #ifdef CONFIG_SECCOMP_FILTER
 253 /* Returns 1 if the parent is an ancestor of the child. */
 254 static int is_ancestor(struct seccomp_filter *parent,
 255                        struct seccomp_filter *child)
 256 {
 257         /* NULL is the root ancestor. */
 258         if (parent == NULL)
 259                 return 1;
 260         for (; child; child = child->prev)
 261                 if (child == parent)
 262                         return 1;
 263         return 0;
 264 }
 265
 266 /**
 267  * seccomp_can_sync_threads: checks if all threads can be synchronized
 268  *
 269  * Expects sighand and cred_guard_mutex locks to be held.
 270  *
 271  * Returns 0 on success, -ve on error, or the pid of a thread which was
 272  * either not in the correct seccomp mode or it did not have an ancestral
 273  * seccomp filter.
 274  */
 275 static inline pid_t seccomp_can_sync_threads(void)
 276 {
 277         struct task_struct *thread, *caller;
 278
 279         BUG_ON(!mutex_is_locked(&current->signal->cred_guard_mutex));
 280         assert_spin_locked(&current->sighand->siglock);
 281
 282         /* Validate all threads being eligible for synchronization. */
 283         caller = current;
 284         for_each_thread(caller, thread) {
 285                 pid_t failed;
 286
 287                 /* Skip current, since it is initiating the sync. */
 288                 if (thread == caller)
 289                         continue;
 290
 291                 if (thread->seccomp.mode == SECCOMP_MODE_DISABLED ||
 292                     (thread->seccomp.mode == SECCOMP_MODE_FILTER &&
 293                      is_ancestor(thread->seccomp.filter,
 294                                  caller->seccomp.filter)))
 295                         continue;
 296
 297                 /* Return the first thread that cannot be synchronized. */
 298                 failed = task_pid_vnr(thread);
 299                 /* If the pid cannot be resolved, then return -ESRCH */
 300                 if (unlikely(WARN_ON(failed == 0)))
 301                         failed = -ESRCH;
 302                 return failed;
 303         }
 304
 305         return 0;
 306 }
 307
 308 /**
 309  * seccomp_sync_threads: sets all threads to use current's filter
 310  *
 311  * Expects sighand and cred_guard_mutex locks to be held, and for
 312  * seccomp_can_sync_threads() to have returned success already
 313  * without dropping the locks.
 314  *
 315  */
 316 static inline void seccomp_sync_threads(unsigned long flags)
 317 {
 318         struct task_struct *thread, *caller;
 319
 320         BUG_ON(!mutex_is_locked(&current->signal->cred_guard_mutex));
 321         assert_spin_locked(&current->sighand->siglock);
 322
 323         /* Synchronize all threads. */
 324         caller = current;
 325         for_each_thread(caller, thread) {
 326                 /* Skip current, since it needs no changes. */
 327                 if (thread == caller)
 328                         continue;
 329
 330                 /* Get a task reference for the new leaf node. */
 331                 get_seccomp_filter(caller);
 332                 /*
 333                  * Drop the task reference to the shared ancestor since
 334                  * current's path will hold a reference.  (This also
 335                  * allows a put before the assignment.)
 336                  */
 337                 put_seccomp_filter(thread);
 338                 smp_store_release(&thread->seccomp.filter,
 339                                   caller->seccomp.filter);
 340
 341                 /*
 342                  * Don't let an unprivileged task work around
 343                  * the no_new_privs restriction by creating
 344                  * a thread that sets it up, enters seccomp,
 345                  * then dies.
 346                  */
 347                 if (task_no_new_privs(caller))
 348                         task_set_no_new_privs(thread);
 349
 350                 /*
 351                  * Opt the other thread into seccomp if needed.
 352                  * As threads are considered to be trust-realm
 353                  * equivalent (see ptrace_may_access), it is safe to
 354                  * allow one thread to transition the other.
 355                  */
 356                 if (thread->seccomp.mode == SECCOMP_MODE_DISABLED)
 357                         seccomp_assign_mode(thread, SECCOMP_MODE_FILTER,
 358                                             flags);
 359         }
 360 }
 361
 362 /**
 363  * seccomp_prepare_filter: Prepares a seccomp filter for use.
 364  * @fprog: BPF program to install
 365  *
 366  * Returns filter on success or an ERR_PTR on failure.
 367  */
 368 static struct seccomp_filter *seccomp_prepare_filter(struct sock_fprog *fprog)
 369 {
 370         struct seccomp_filter *sfilter;
 371         int ret;
 372         const bool save_orig = IS_ENABLED(CONFIG_CHECKPOINT_RESTORE);
 373
 374         if (fprog->len == 0 || fprog->len > BPF_MAXINSNS)
 375                 return ERR_PTR(-EINVAL);
 376
 377         BUG_ON(INT_MAX / fprog->len < sizeof(struct sock_filter));
 378
 379         /*
 380          * Installing a seccomp filter requires that the task has
 381          * CAP_SYS_ADMIN in its namespace or be running with no_new_privs.
 382          * This avoids scenarios where unprivileged tasks can affect the
 383          * behavior of privileged children.
 384          */
 385         if (!task_no_new_privs(current) &&
 386             security_capable_noaudit(current_cred(), current_user_ns(),
 387                                      CAP_SYS_ADMIN) != 0)
 388                 return ERR_PTR(-EACCES);
 389
 390         /* Allocate a new seccomp_filter */
 391         sfilter = kzalloc(sizeof(*sfilter), GFP_KERNEL | __GFP_NOWARN);
 392         if (!sfilter)
 393                 return ERR_PTR(-ENOMEM);
 394
 395         ret = bpf_prog_create_from_user(&sfilter->prog, fprog,
 396                                         seccomp_check_filter, save_orig);
 397         if (ret < 0) {
 398                 kfree(sfilter);
 399                 return ERR_PTR(ret);
 400         }
 401
 402         refcount_set(&sfilter->usage, 1);
 403
 404         return sfilter;
 405 }
 406
 407 /**
 408  * seccomp_prepare_user_filter - prepares a user-supplied sock_fprog
 409  * @user_filter: pointer to the user data containing a sock_fprog.
 410  *
 411  * Returns 0 on success and non-zero otherwise.
 412  */
 413 static struct seccomp_filter *
 414 seccomp_prepare_user_filter(const char __user *user_filter)
 415 {
 416         struct sock_fprog fprog;
 417         struct seccomp_filter *filter = ERR_PTR(-EFAULT);
 418
 419 #ifdef CONFIG_COMPAT
 420         if (in_compat_syscall()) {
 421                 struct compat_sock_fprog fprog32;
 422                 if (copy_from_user(&fprog32, user_filter, sizeof(fprog32)))
 423                         goto out;
 424                 fprog.len = fprog32.len;
 425                 fprog.filter = compat_ptr(fprog32.filter);
 426         } else /* falls through to the if below. */
 427 #endif
 428         if (copy_from_user(&fprog, user_filter, sizeof(fprog)))
 429                 goto out;
 430         filter = seccomp_prepare_filter(&fprog);
 431 out:
 432         return filter;
 433 }
 434
 435 /**
 436  * seccomp_attach_filter: validate and attach filter
 437  * @flags:  flags to change filter behavior
 438  * @filter: seccomp filter to add to the current process
 439  *
 440  * Caller must be holding current->sighand->siglock lock.
 441  *
 442  * Returns 0 on success, -ve on error.
 443  */
 444 static long seccomp_attach_filter(unsigned int flags,
 445                                   struct seccomp_filter *filter)
 446 {
 447         unsigned long total_insns;
 448         struct seccomp_filter *walker;
 449
 450         assert_spin_locked(&current->sighand->siglock);
 451
 452         /* Validate resulting filter length. */
 453         total_insns = filter->prog->len;
 454         for (walker = current->seccomp.filter; walker; walker = walker->prev)
 455                 total_insns += walker->prog->len + 4;  /* 4 instr penalty */
 456         if (total_insns > MAX_INSNS_PER_PATH)
 457                 return -ENOMEM;
 458
 459         /* If thread sync has been requested, check that it is possible. */
 460         if (flags & SECCOMP_FILTER_FLAG_TSYNC) {
 461                 int ret;
 462
 463                 ret = seccomp_can_sync_threads();
 464                 if (ret)
 465                         return ret;
 466         }
 467
 468         /* Set log flag, if present. */
 469         if (flags & SECCOMP_FILTER_FLAG_LOG)
 470                 filter->log = true;
 471
 472         /*
 473          * If there is an existing filter, make it the prev and don't drop its
 474          * task reference.
 475          */
 476         filter->prev = current->seccomp.filter;
 477         current->seccomp.filter = filter;
 478
 479         /* Now that the new filter is in place, synchronize to all threads. */
 480         if (flags & SECCOMP_FILTER_FLAG_TSYNC)
 481                 seccomp_sync_threads(flags);
 482
 483         return 0;
 484 }
 485
 486 static void __get_seccomp_filter(struct seccomp_filter *filter)
 487 {
 488         /* Reference count is bounded by the number of total processes. */
 489         refcount_inc(&filter->usage);
 490 }
 491
 492 /* get_seccomp_filter - increments the reference count of the filter on @tsk */
 493 void get_seccomp_filter(struct task_struct *tsk)
 494 {
 495         struct seccomp_filter *orig = tsk->seccomp.filter;
 496         if (!orig)
 497                 return;
 498         __get_seccomp_filter(orig);
 499 }
 500
 501 static inline void seccomp_filter_free(struct seccomp_filter *filter)
 502 {
 503         if (filter) {
 504                 bpf_prog_destroy(filter->prog);
 505                 kfree(filter);
 506         }
 507 }
 508
 509 static void __put_seccomp_filter(struct seccomp_filter *orig)
 510 {
 511         /* Clean up single-reference branches iteratively. */
 512         while (orig && refcount_dec_and_test(&orig->usage)) {
 513                 struct seccomp_filter *freeme = orig;
 514                 orig = orig->prev;
 515                 seccomp_filter_free(freeme);
 516         }
 517 }
 518
 519 /* put_seccomp_filter - decrements the ref count of tsk->seccomp.filter */
 520 void put_seccomp_filter(struct task_struct *tsk)
 521 {
 522         __put_seccomp_filter(tsk->seccomp.filter);
 523 }
 524
 525 static void seccomp_init_siginfo(siginfo_t *info, int syscall, int reason)
 526 {
 527         clear_siginfo(info);
 528         info->si_signo = SIGSYS;
 529         info->si_code = SYS_SECCOMP;
 530         info->si_call_addr = (void __user *)KSTK_EIP(current);
 531         info->si_errno = reason;
 532         info->si_arch = syscall_get_arch();
 533         info->si_syscall = syscall;
 534 }
 535
 536 /**
 537  * seccomp_send_sigsys - signals the task to allow in-process syscall emulation
 538  * @syscall: syscall number to send to userland
 539  * @reason: filter-supplied reason code to send to userland (via si_errno)
 540  *
 541  * Forces a SIGSYS with a code of SYS_SECCOMP and related sigsys info.
 542  */
 543 static void seccomp_send_sigsys(int syscall, int reason)
 544 {
 545         struct siginfo info;
 546         seccomp_init_siginfo(&info, syscall, reason);
 547         force_sig_info(SIGSYS, &info, current);
 548 }
 549 #endif  /* CONFIG_SECCOMP_FILTER */
 550
 551 /* For use with seccomp_actions_logged */
 552 #define SECCOMP_LOG_KILL_PROCESS        (1 << 0)
 553 #define SECCOMP_LOG_KILL_THREAD         (1 << 1)
 554 #define SECCOMP_LOG_TRAP                (1 << 2)
 555 #define SECCOMP_LOG_ERRNO               (1 << 3)
 556 #define SECCOMP_LOG_TRACE               (1 << 4)
 557 #define SECCOMP_LOG_LOG                 (1 << 5)
 558 #define SECCOMP_LOG_ALLOW               (1 << 6)
 559
 560 static u32 seccomp_actions_logged = SECCOMP_LOG_KILL_PROCESS |
 561                                     SECCOMP_LOG_KILL_THREAD  |
 562                                     SECCOMP_LOG_TRAP  |
 563                                     SECCOMP_LOG_ERRNO |
 564                                     SECCOMP_LOG_TRACE |
 565                                     SECCOMP_LOG_LOG;
 566
 567 static inline void seccomp_log(unsigned long syscall, long signr, u32 action,
 568                                bool requested)
 569 {
 570         bool log = false;
 571
 572         switch (action) {
 573         case SECCOMP_RET_ALLOW:
 574                 break;
 575         case SECCOMP_RET_TRAP:
 576                 log = requested && seccomp_actions_logged & SECCOMP_LOG_TRAP;
 577                 break;
 578         case SECCOMP_RET_ERRNO:
 579                 log = requested && seccomp_actions_logged & SECCOMP_LOG_ERRNO;
 580                 break;
 581         case SECCOMP_RET_TRACE:
 582                 log = requested && seccomp_actions_logged & SECCOMP_LOG_TRACE;
 583                 break;
 584         case SECCOMP_RET_LOG:
 585                 log = seccomp_actions_logged & SECCOMP_LOG_LOG;
 586                 break;
 587         case SECCOMP_RET_KILL_THREAD:
 588                 log = seccomp_actions_logged & SECCOMP_LOG_KILL_THREAD;
 589                 break;
 590         case SECCOMP_RET_KILL_PROCESS:
 591         default:
 592                 log = seccomp_actions_logged & SECCOMP_LOG_KILL_PROCESS;
 593         }
 594
 595         /*
 596          * Emit an audit message when the action is RET_KILL_*, RET_LOG, or the
 597          * FILTER_FLAG_LOG bit was set. The admin has the ability to silence
 598          * any action from being logged by removing the action name from the
 599          * seccomp_actions_logged sysctl.
 600          */
 601         if (!log)
 602                 return;
 603
 604         audit_seccomp(syscall, signr, action);
 605 }
 606
 607 /*
 608  * Secure computing mode 1 allows only read/write/exit/sigreturn.
 609  * To be fully secure this must be combined with rlimit
 610  * to limit the stack allocations too.
 611  */
 612 static const int mode1_syscalls[] = {
 613         __NR_seccomp_read, __NR_seccomp_write, __NR_seccomp_exit, __NR_seccomp_sigreturn,
 614         0, /* null terminated */
 615 };
 616
 617 static void __secure_computing_strict(int this_syscall)
 618 {
 619         const int *syscall_whitelist = mode1_syscalls;
 620 #ifdef CONFIG_COMPAT
 621         if (in_compat_syscall())
 622                 syscall_whitelist = get_compat_mode1_syscalls();
 623 #endif
 624         do {
 625                 if (*syscall_whitelist == this_syscall)
 626                         return;
 627         } while (*++syscall_whitelist);
 628
 629 #ifdef SECCOMP_DEBUG
 630         dump_stack();
 631 #endif
 632         seccomp_log(this_syscall, SIGKILL, SECCOMP_RET_KILL_THREAD, true);
 633         do_exit(SIGKILL);
 634 }
 635
 636 #ifndef CONFIG_HAVE_ARCH_SECCOMP_FILTER
 637 void secure_computing_strict(int this_syscall)
 638 {
 639         int mode = current->seccomp.mode;
 640
 641         if (IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) &&
 642             unlikely(current->ptrace & PT_SUSPEND_SECCOMP))
 643                 return;
 644
 645         if (mode == SECCOMP_MODE_DISABLED)
 646                 return;
 647         else if (mode == SECCOMP_MODE_STRICT)
 648                 __secure_computing_strict(this_syscall);
 649         else
 650                 BUG();
 651 }
 652 #else
 653
 654 #ifdef CONFIG_SECCOMP_FILTER
 655 static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd,
 656                             const bool recheck_after_trace)
 657 {
 658         u32 filter_ret, action;
 659         struct seccomp_filter *match = NULL;
 660         int data;
 661
 662         /*
 663          * Make sure that any changes to mode from another thread have
 664          * been seen after TIF_SECCOMP was seen.
 665          */
 666         rmb();
 667
 668         filter_ret = seccomp_run_filters(sd, &match);
 669         data = filter_ret & SECCOMP_RET_DATA;
 670         action = filter_ret & SECCOMP_RET_ACTION_FULL;
 671
 672         switch (action) {
 673         case SECCOMP_RET_ERRNO:
 674                 /* Set low-order bits as an errno, capped at MAX_ERRNO. */
 675                 if (data > MAX_ERRNO)
 676                         data = MAX_ERRNO;
 677                 syscall_set_return_value(current, task_pt_regs(current),
 678                                          -data, 0);
 679                 goto skip;
 680
 681         case SECCOMP_RET_TRAP:
 682                 /* Show the handler the original registers. */
 683                 syscall_rollback(current, task_pt_regs(current));
 684                 /* Let the filter pass back 16 bits of data. */
 685                 seccomp_send_sigsys(this_syscall, data);
 686                 goto skip;
 687
 688         case SECCOMP_RET_TRACE:
 689                 /* We've been put in this state by the ptracer already. */
 690                 if (recheck_after_trace)
 691                         return 0;
 692
 693                 /* ENOSYS these calls if there is no tracer attached. */
 694                 if (!ptrace_event_enabled(current, PTRACE_EVENT_SECCOMP)) {
 695                         syscall_set_return_value(current,
 696                                                  task_pt_regs(current),
 697                                                  -ENOSYS, 0);
 698                         goto skip;
 699                 }
 700
 701                 /* Allow the BPF to provide the event message */
 702                 ptrace_event(PTRACE_EVENT_SECCOMP, data);
 703                 /*
 704                  * The delivery of a fatal signal during event
 705                  * notification may silently skip tracer notification,
 706                  * which could leave us with a potentially unmodified
 707                  * syscall that the tracer would have liked to have
 708                  * changed. Since the process is about to die, we just
 709                  * force the syscall to be skipped and let the signal
 710                  * kill the process and correctly handle any tracer exit
 711                  * notifications.
 712                  */
 713                 if (fatal_signal_pending(current))
 714                         goto skip;
 715                 /* Check if the tracer forced the syscall to be skipped. */
 716                 this_syscall = syscall_get_nr(current, task_pt_regs(current));
 717                 if (this_syscall < 0)
 718                         goto skip;
 719
 720                 /*
 721                  * Recheck the syscall, since it may have changed. This
 722                  * intentionally uses a NULL struct seccomp_data to force
 723                  * a reload of all registers. This does not goto skip since
 724                  * a skip would have already been reported.
 725                  */
 726                 if (__seccomp_filter(this_syscall, NULL, true))
 727                         return -1;
 728
 729                 return 0;
 730
 731         case SECCOMP_RET_LOG:
 732                 seccomp_log(this_syscall, 0, action, true);
 733                 return 0;
 734
 735         case SECCOMP_RET_ALLOW:
 736                 /*
 737                  * Note that the "match" filter will always be NULL for
 738                  * this action since SECCOMP_RET_ALLOW is the starting
 739                  * state in seccomp_run_filters().
 740                  */
 741                 return 0;
 742
 743         case SECCOMP_RET_KILL_THREAD:
 744         case SECCOMP_RET_KILL_PROCESS:
 745         default:
 746                 seccomp_log(this_syscall, SIGSYS, action, true);
 747                 /* Dump core only if this is the last remaining thread. */
 748                 if (action == SECCOMP_RET_KILL_PROCESS ||
 749                     get_nr_threads(current) == 1) {
 750                         siginfo_t info;
 751
 752                         /* Show the original registers in the dump. */
 753                         syscall_rollback(current, task_pt_regs(current));
 754                         /* Trigger a manual coredump since do_exit skips it. */
 755                         seccomp_init_siginfo(&info, this_syscall, data);
 756                         do_coredump(&info);
 757                 }
 758                 if (action == SECCOMP_RET_KILL_PROCESS)
 759                         do_group_exit(SIGSYS);
 760                 else
 761                         do_exit(SIGSYS);
 762         }
 763
 764         unreachable();
 765
 766 skip:
 767         seccomp_log(this_syscall, 0, action, match ? match->log : false);
 768         return -1;
 769 }
 770 #else
 771 static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd,
 772                             const bool recheck_after_trace)
 773 {
 774         BUG();
 775 }
 776 #endif
 777
 778 int __secure_computing(const struct seccomp_data *sd)
 779 {
 780         int mode = current->seccomp.mode;
 781         int this_syscall;
 782
 783         if (IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) &&
 784             unlikely(current->ptrace & PT_SUSPEND_SECCOMP))
 785                 return 0;
 786
 787         this_syscall = sd ? sd->nr :
 788                 syscall_get_nr(current, task_pt_regs(current));
 789
 790         switch (mode) {
 791         case SECCOMP_MODE_STRICT:
 792                 __secure_computing_strict(this_syscall);  /* may call do_exit */
 793                 return 0;
 794         case SECCOMP_MODE_FILTER:
 795                 return __seccomp_filter(this_syscall, sd, false);
 796         default:
 797                 BUG();
 798         }
 799 }
 800 #endif /* CONFIG_HAVE_ARCH_SECCOMP_FILTER */
 801
 802 long prctl_get_seccomp(void)
 803 {
 804         return current->seccomp.mode;
 805 }
 806
 807 /**
 808  * seccomp_set_mode_strict: internal function for setting strict seccomp
 809  *
 810  * Once current->seccomp.mode is non-zero, it may not be changed.
 811  *
 812  * Returns 0 on success or -EINVAL on failure.
 813  */
 814 static long seccomp_set_mode_strict(void)
 815 {
 816         const unsigned long seccomp_mode = SECCOMP_MODE_STRICT;
 817         long ret = -EINVAL;
 818
 819         spin_lock_irq(&current->sighand->siglock);
 820
 821         if (!seccomp_may_assign_mode(seccomp_mode))
 822                 goto out;
 823
 824 #ifdef TIF_NOTSC
 825         disable_TSC();
 826 #endif
 827         seccomp_assign_mode(current, seccomp_mode, 0);
 828         ret = 0;
 829
 830 out:
 831         spin_unlock_irq(&current->sighand->siglock);
 832
 833         return ret;
 834 }
 835
 836 #ifdef CONFIG_SECCOMP_FILTER
 837 /**
 838  * seccomp_set_mode_filter: internal function for setting seccomp filter
 839  * @flags:  flags to change filter behavior
 840  * @filter: struct sock_fprog containing filter
 841  *
 842  * This function may be called repeatedly to install additional filters.
 843  * Every filter successfully installed will be evaluated (in reverse order)
 844  * for each system call the task makes.
 845  *
 846  * Once current->seccomp.mode is non-zero, it may not be changed.
 847  *
 848  * Returns 0 on success or -EINVAL on failure.
 849  */
 850 static long seccomp_set_mode_filter(unsigned int flags,
 851                                     const char __user *filter)
 852 {
 853         const unsigned long seccomp_mode = SECCOMP_MODE_FILTER;
 854         struct seccomp_filter *prepared = NULL;
 855         long ret = -EINVAL;
 856
 857         /* Validate flags. */
 858         if (flags & ~SECCOMP_FILTER_FLAG_MASK)
 859                 return -EINVAL;
 860
 861         /* Prepare the new filter before holding any locks. */
 862         prepared = seccomp_prepare_user_filter(filter);
 863         if (IS_ERR(prepared))
 864                 return PTR_ERR(prepared);
 865
 866         /*
 867          * Make sure we cannot change seccomp or nnp state via TSYNC
 868          * while another thread is in the middle of calling exec.
 869          */
 870         if (flags & SECCOMP_FILTER_FLAG_TSYNC &&
 871             mutex_lock_killable(&current->signal->cred_guard_mutex))
 872                 goto out_free;
 873
 874         spin_lock_irq(&current->sighand->siglock);
 875
 876         if (!seccomp_may_assign_mode(seccomp_mode))
 877                 goto out;
 878
 879         ret = seccomp_attach_filter(flags, prepared);
 880         if (ret)
 881                 goto out;
 882         /* Do not free the successfully attached filter. */
 883         prepared = NULL;
 884
 885         seccomp_assign_mode(current, seccomp_mode, flags);
 886 out:
 887         spin_unlock_irq(&current->sighand->siglock);
 888         if (flags & SECCOMP_FILTER_FLAG_TSYNC)
 889                 mutex_unlock(&current->signal->cred_guard_mutex);
 890 out_free:
 891         seccomp_filter_free(prepared);
 892         return ret;
 893 }
 894 #else
 895 static inline long seccomp_set_mode_filter(unsigned int flags,
 896                                            const char __user *filter)
 897 {
 898         return -EINVAL;
 899 }
 900 #endif
 901
 902 static long seccomp_get_action_avail(const char __user *uaction)
 903 {
 904         u32 action;
 905
 906         if (copy_from_user(&action, uaction, sizeof(action)))
 907                 return -EFAULT;
 908
 909         switch (action) {
 910         case SECCOMP_RET_KILL_PROCESS:
 911         case SECCOMP_RET_KILL_THREAD:
 912         case SECCOMP_RET_TRAP:
 913         case SECCOMP_RET_ERRNO:
 914         case SECCOMP_RET_TRACE:
 915         case SECCOMP_RET_LOG:
 916         case SECCOMP_RET_ALLOW:
 917                 break;
 918         default:
 919                 return -EOPNOTSUPP;
 920         }
 921
 922         return 0;
 923 }
 924
 925 /* Common entry point for both prctl and syscall. */
 926 static long do_seccomp(unsigned int op, unsigned int flags,
 927                        const char __user *uargs)
 928 {
 929         switch (op) {
 930         case SECCOMP_SET_MODE_STRICT:
 931                 if (flags != 0 || uargs != NULL)
 932                         return -EINVAL;
 933                 return seccomp_set_mode_strict();
 934         case SECCOMP_SET_MODE_FILTER:
 935                 return seccomp_set_mode_filter(flags, uargs);
 936         case SECCOMP_GET_ACTION_AVAIL:
 937                 if (flags != 0)
 938                         return -EINVAL;
 939
 940                 return seccomp_get_action_avail(uargs);
 941         default:
 942                 return -EINVAL;
 943         }
 944 }
 945
 946 SYSCALL_DEFINE3(seccomp, unsigned int, op, unsigned int, flags,
 947                          const char __user *, uargs)
 948 {
 949         return do_seccomp(op, flags, uargs);
 950 }
 951
 952 /**
 953  * prctl_set_seccomp: configures current->seccomp.mode
 954  * @seccomp_mode: requested mode to use
 955  * @filter: optional struct sock_fprog for use with SECCOMP_MODE_FILTER
 956  *
 957  * Returns 0 on success or -EINVAL on failure.
 958  */
 959 long prctl_set_seccomp(unsigned long seccomp_mode, char __user *filter)
 960 {
 961         unsigned int op;
 962         char __user *uargs;
 963
 964         switch (seccomp_mode) {
 965         case SECCOMP_MODE_STRICT:
 966                 op = SECCOMP_SET_MODE_STRICT;
 967                 /*
 968                  * Setting strict mode through prctl always ignored filter,
 969                  * so make sure it is always NULL here to pass the internal
 970                  * check in do_seccomp().
 971                  */
 972                 uargs = NULL;
 973                 break;
 974         case SECCOMP_MODE_FILTER:
 975                 op = SECCOMP_SET_MODE_FILTER;
 976                 uargs = filter;
 977                 break;
 978         default:
 979                 return -EINVAL;
 980         }
 981
 982         /* prctl interface doesn't have flags, so they are always zero. */
 983         return do_seccomp(op, 0, uargs);
 984 }
 985
 986 #if defined(CONFIG_SECCOMP_FILTER) && defined(CONFIG_CHECKPOINT_RESTORE)
 987 static struct seccomp_filter *get_nth_filter(struct task_struct *task,
 988                                              unsigned long filter_off)
 989 {
 990         struct seccomp_filter *orig, *filter;
 991         unsigned long count;
 992
 993         /*
 994          * Note: this is only correct because the caller should be the (ptrace)
 995          * tracer of the task, otherwise lock_task_sighand is needed.
 996          */
 997         spin_lock_irq(&task->sighand->siglock);
 998
 999         if (task->seccomp.mode != SECCOMP_MODE_FILTER) {
1000                 spin_unlock_irq(&task->sighand->siglock);
1001                 return ERR_PTR(-EINVAL);
1002         }
1003
1004         orig = task->seccomp.filter;
1005         __get_seccomp_filter(orig);
1006         spin_unlock_irq(&task->sighand->siglock);
1007
1008         count = 0;
1009         for (filter = orig; filter; filter = filter->prev)
1010                 count++;
1011
1012         if (filter_off >= count) {
1013                 filter = ERR_PTR(-ENOENT);
1014                 goto out;
1015         }
1016
1017         count -= filter_off;
1018         for (filter = orig; filter && count > 1; filter = filter->prev)
1019                 count--;
1020
1021         if (WARN_ON(count != 1 || !filter)) {
1022                 filter = ERR_PTR(-ENOENT);
1023                 goto out;
1024         }
1025
1026         __get_seccomp_filter(filter);
1027
1028 out:
1029         __put_seccomp_filter(orig);
1030         return filter;
1031 }
1032
1033 long seccomp_get_filter(struct task_struct *task, unsigned long filter_off,
1034                         void __user *data)
1035 {
1036         struct seccomp_filter *filter;
1037         struct sock_fprog_kern *fprog;
1038         long ret;
1039
1040         if (!capable(CAP_SYS_ADMIN) ||
1041             current->seccomp.mode != SECCOMP_MODE_DISABLED) {
1042                 return -EACCES;
1043         }
1044
1045         filter = get_nth_filter(task, filter_off);
1046         if (IS_ERR(filter))
1047                 return PTR_ERR(filter);
1048
1049         fprog = filter->prog->orig_prog;
1050         if (!fprog) {
1051                 /* This must be a new non-cBPF filter, since we save
1052                  * every cBPF filter's orig_prog above when
1053                  * CONFIG_CHECKPOINT_RESTORE is enabled.
1054                  */
1055                 ret = -EMEDIUMTYPE;
1056                 goto out;
1057         }
1058
1059         ret = fprog->len;
1060         if (!data)
1061                 goto out;
1062
1063         if (copy_to_user(data, fprog->filter, bpf_classic_proglen(fprog)))
1064                 ret = -EFAULT;
1065
1066 out:
1067         __put_seccomp_filter(filter);
1068         return ret;
1069 }
1070
1071 long seccomp_get_metadata(struct task_struct *task,
1072                           unsigned long size, void __user *data)
1073 {
1074         long ret;
1075         struct seccomp_filter *filter;
1076         struct seccomp_metadata kmd = {};
1077
1078         if (!capable(CAP_SYS_ADMIN) ||
1079             current->seccomp.mode != SECCOMP_MODE_DISABLED) {
1080                 return -EACCES;
1081         }
1082
1083         size = min_t(unsigned long, size, sizeof(kmd));
1084
1085         if (size < sizeof(kmd.filter_off))
1086                 return -EINVAL;
1087
1088         if (copy_from_user(&kmd.filter_off, data, sizeof(kmd.filter_off)))
1089                 return -EFAULT;
1090
1091         filter = get_nth_filter(task, kmd.filter_off);
1092         if (IS_ERR(filter))
1093                 return PTR_ERR(filter);
1094
1095         if (filter->log)
1096                 kmd.flags |= SECCOMP_FILTER_FLAG_LOG;
1097
1098         ret = size;
1099         if (copy_to_user(data, &kmd, size))
1100                 ret = -EFAULT;
1101
1102         __put_seccomp_filter(filter);
1103         return ret;
1104 }
1105 #endif
1106
1107 #ifdef CONFIG_SYSCTL
1108
1109 /* Human readable action names for friendly sysctl interaction */
1110 #define SECCOMP_RET_KILL_PROCESS_NAME   "kill_process"
1111 #define SECCOMP_RET_KILL_THREAD_NAME    "kill_thread"
1112 #define SECCOMP_RET_TRAP_NAME           "trap"
1113 #define SECCOMP_RET_ERRNO_NAME          "errno"
1114 #define SECCOMP_RET_TRACE_NAME          "trace"
1115 #define SECCOMP_RET_LOG_NAME            "log"
1116 #define SECCOMP_RET_ALLOW_NAME          "allow"
1117
1118 static const char seccomp_actions_avail[] =
1119                                 SECCOMP_RET_KILL_PROCESS_NAME   " "
1120                                 SECCOMP_RET_KILL_THREAD_NAME    " "
1121                                 SECCOMP_RET_TRAP_NAME           " "
1122                                 SECCOMP_RET_ERRNO_NAME          " "
1123                                 SECCOMP_RET_TRACE_NAME          " "
1124                                 SECCOMP_RET_LOG_NAME            " "
1125                                 SECCOMP_RET_ALLOW_NAME;
1126
1127 struct seccomp_log_name {
1128         u32             log;
1129         const char      *name;
1130 };
1131
1132 static const struct seccomp_log_name seccomp_log_names[] = {
1133         { SECCOMP_LOG_KILL_PROCESS, SECCOMP_RET_KILL_PROCESS_NAME },
1134         { SECCOMP_LOG_KILL_THREAD, SECCOMP_RET_KILL_THREAD_NAME },
1135         { SECCOMP_LOG_TRAP, SECCOMP_RET_TRAP_NAME },
1136         { SECCOMP_LOG_ERRNO, SECCOMP_RET_ERRNO_NAME },
1137         { SECCOMP_LOG_TRACE, SECCOMP_RET_TRACE_NAME },
1138         { SECCOMP_LOG_LOG, SECCOMP_RET_LOG_NAME },
1139         { SECCOMP_LOG_ALLOW, SECCOMP_RET_ALLOW_NAME },
1140         { }
1141 };
1142
1143 static bool seccomp_names_from_actions_logged(char *names, size_t size,
1144                                               u32 actions_logged,
1145                                               const char *sep)
1146 {
1147         const struct seccomp_log_name *cur;
1148         bool append_sep = false;
1149
1150         for (cur = seccomp_log_names; cur->name && size; cur++) {
1151                 ssize_t ret;
1152
1153                 if (!(actions_logged & cur->log))
1154                         continue;
1155
1156                 if (append_sep) {
1157                         ret = strscpy(names, sep, size);
1158                         if (ret < 0)
1159                                 return false;
1160
1161                         names += ret;
1162                         size -= ret;
1163                 } else
1164                         append_sep = true;
1165
1166                 ret = strscpy(names, cur->name, size);
1167                 if (ret < 0)
1168                         return false;
1169
1170                 names += ret;
1171                 size -= ret;
1172         }
1173
1174         return true;
1175 }
1176
1177 static bool seccomp_action_logged_from_name(u32 *action_logged,
1178                                             const char *name)
1179 {
1180         const struct seccomp_log_name *cur;
1181
1182         for (cur = seccomp_log_names; cur->name; cur++) {
1183                 if (!strcmp(cur->name, name)) {
1184                         *action_logged = cur->log;
1185                         return true;
1186                 }
1187         }
1188
1189         return false;
1190 }
1191
1192 static bool seccomp_actions_logged_from_names(u32 *actions_logged, char *names)
1193 {
1194         char *name;
1195
1196         *actions_logged = 0;
1197         while ((name = strsep(&names, " ")) && *name) {
1198                 u32 action_logged = 0;
1199
1200                 if (!seccomp_action_logged_from_name(&action_logged, name))
1201                         return false;
1202
1203                 *actions_logged |= action_logged;
1204         }
1205
1206         return true;
1207 }
1208
1209 static int read_actions_logged(struct ctl_table *ro_table, void __user *buffer,
1210                                size_t *lenp, loff_t *ppos)
1211 {
1212         char names[sizeof(seccomp_actions_avail)];
1213         struct ctl_table table;
1214
1215         memset(names, 0, sizeof(names));
1216
1217         if (!seccomp_names_from_actions_logged(names, sizeof(names),
1218                                                seccomp_actions_logged, " "))
1219                 return -EINVAL;
1220
1221         table = *ro_table;
1222         table.data = names;
1223         table.maxlen = sizeof(names);
1224         return proc_dostring(&table, 0, buffer, lenp, ppos);
1225 }
1226
1227 static int write_actions_logged(struct ctl_table *ro_table, void __user *buffer,
1228                                 size_t *lenp, loff_t *ppos, u32 *actions_logged)
1229 {
1230         char names[sizeof(seccomp_actions_avail)];
1231         struct ctl_table table;
1232         int ret;
1233
1234         if (!capable(CAP_SYS_ADMIN))
1235                 return -EPERM;
1236
1237         memset(names, 0, sizeof(names));
1238
1239         table = *ro_table;
1240         table.data = names;
1241         table.maxlen = sizeof(names);
1242         ret = proc_dostring(&table, 1, buffer, lenp, ppos);
1243         if (ret)
1244                 return ret;
1245
1246         if (!seccomp_actions_logged_from_names(actions_logged, table.data))
1247                 return -EINVAL;
1248
1249         if (*actions_logged & SECCOMP_LOG_ALLOW)
1250                 return -EINVAL;
1251
1252         seccomp_actions_logged = *actions_logged;
1253         return 0;
1254 }
1255
1256 static void audit_actions_logged(u32 actions_logged, u32 old_actions_logged,
1257                                  int ret)
1258 {
1259         char names[sizeof(seccomp_actions_avail)];
1260         char old_names[sizeof(seccomp_actions_avail)];
1261         const char *new = names;
1262         const char *old = old_names;
1263
1264         if (!audit_enabled)
1265                 return;
1266
1267         memset(names, 0, sizeof(names));
1268         memset(old_names, 0, sizeof(old_names));
1269
1270         if (ret)
1271                 new = "?";
1272         else if (!actions_logged)
1273                 new = "(none)";
1274         else if (!seccomp_names_from_actions_logged(names, sizeof(names),
1275                                                     actions_logged, ","))
1276                 new = "?";
1277
1278         if (!old_actions_logged)
1279                 old = "(none)";
1280         else if (!seccomp_names_from_actions_logged(old_names,
1281                                                     sizeof(old_names),
1282                                                     old_actions_logged, ","))
1283                 old = "?";
1284
1285         return audit_seccomp_actions_logged(new, old, !ret);
1286 }
1287
1288 static int seccomp_actions_logged_handler(struct ctl_table *ro_table, int write,
1289                                           void __user *buffer, size_t *lenp,
1290                                           loff_t *ppos)
1291 {
1292         int ret;
1293
1294         if (write) {
1295                 u32 actions_logged = 0;
1296                 u32 old_actions_logged = seccomp_actions_logged;
1297
1298                 ret = write_actions_logged(ro_table, buffer, lenp, ppos,
1299                                            &actions_logged);
1300                 audit_actions_logged(actions_logged, old_actions_logged, ret);
1301         } else
1302                 ret = read_actions_logged(ro_table, buffer, lenp, ppos);
1303
1304         return ret;
1305 }
1306
1307 static struct ctl_path seccomp_sysctl_path[] = {
1308         { .procname = "kernel", },
1309         { .procname = "seccomp", },
1310         { }
1311 };
1312
1313 static struct ctl_table seccomp_sysctl_table[] = {
1314         {
1315                 .procname       = "actions_avail",
1316                 .data           = (void *) &seccomp_actions_avail,
1317                 .maxlen         = sizeof(seccomp_actions_avail),
1318                 .mode           = 0444,
1319                 .proc_handler   = proc_dostring,
1320         },
1321         {
1322                 .procname       = "actions_logged",
1323                 .mode           = 0644,
1324                 .proc_handler   = seccomp_actions_logged_handler,
1325         },
1326         { }
1327 };
1328
1329 static int __init seccomp_sysctl_init(void)
1330 {
1331         struct ctl_table_header *hdr;
1332
1333         hdr = register_sysctl_paths(seccomp_sysctl_path, seccomp_sysctl_table);
1334         if (!hdr)
1335                 pr_warn("seccomp: sysctl registration failed\n");
1336         else
1337                 kmemleak_not_leak(hdr);
1338
1339         return 0;
1340 }
1341
1342 device_initcall(seccomp_sysctl_init)
1343
1344 #endif /* CONFIG_SYSCTL */