1 // SPDX-License-Identifier: GPL-2.0
3 * linux/kernel/seccomp.c
5 * Copyright 2004-2005 Andrea Arcangeli <andrea@cpushare.com>
7 * Copyright (C) 2012 Google, Inc.
8 * Will Drewry <wad@chromium.org>
10 * This defines a simple but solid secure-computing facility.
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.
16 #define pr_fmt(fmt) "seccomp: " fmt
18 #include <linux/refcount.h>
19 #include <linux/audit.h>
20 #include <linux/compat.h>
21 #include <linux/coredump.h>
22 #include <linux/kmemleak.h>
23 #include <linux/nospec.h>
24 #include <linux/prctl.h>
25 #include <linux/sched.h>
26 #include <linux/sched/task_stack.h>
27 #include <linux/seccomp.h>
28 #include <linux/slab.h>
29 #include <linux/syscalls.h>
30 #include <linux/sysctl.h>
32 /* Not exposed in headers: strictly internal use only. */
33 #define SECCOMP_MODE_DEAD (SECCOMP_MODE_FILTER + 1)
35 #ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER
36 #include <asm/syscall.h>
39 #ifdef CONFIG_SECCOMP_FILTER
40 #include <linux/file.h>
41 #include <linux/filter.h>
42 #include <linux/pid.h>
43 #include <linux/ptrace.h>
44 #include <linux/capability.h>
45 #include <linux/uaccess.h>
46 #include <linux/anon_inodes.h>
47 #include <linux/lockdep.h>
50 * When SECCOMP_IOCTL_NOTIF_ID_VALID was first introduced, it had the
51 * wrong direction flag in the ioctl number. This is the broken one,
52 * which the kernel needs to keep supporting until all userspaces stop
53 * using the wrong command number.
55 #define SECCOMP_IOCTL_NOTIF_ID_VALID_WRONG_DIR SECCOMP_IOR(2, __u64)
60 SECCOMP_NOTIFY_REPLIED
,
63 struct seccomp_knotif
{
64 /* The struct pid of the task whose filter triggered the notification */
65 struct task_struct
*task
;
67 /* The "cookie" for this request; this is unique for this filter. */
71 * The seccomp data. This pointer is valid the entire time this
72 * notification is active, since it comes from __seccomp_filter which
73 * eclipses the entire lifecycle here.
75 const struct seccomp_data
*data
;
78 * Notification states. When SECCOMP_RET_USER_NOTIF is returned, a
79 * struct seccomp_knotif is created and starts out in INIT. Once the
80 * handler reads the notification off of an FD, it transitions to SENT.
81 * If a signal is received the state transitions back to INIT and
82 * another message is sent. When the userspace handler replies, state
83 * transitions to REPLIED.
85 enum notify_state state
;
87 /* The return values, only valid when in SECCOMP_NOTIFY_REPLIED */
93 * Signals when this has changed states, such as the listener
94 * dying, a new seccomp addfd message, or changing to REPLIED
96 struct completion ready
;
98 struct list_head list
;
100 /* outstanding addfd requests */
101 struct list_head addfd
;
105 * struct seccomp_kaddfd - container for seccomp_addfd ioctl messages
107 * @file: A reference to the file to install in the other task
108 * @fd: The fd number to install it at. If the fd number is -1, it means the
109 * installing process should allocate the fd as normal.
110 * @flags: The flags for the new file descriptor. At the moment, only O_CLOEXEC
112 * @ioctl_flags: The flags used for the seccomp_addfd ioctl.
113 * @setfd: whether or not SECCOMP_ADDFD_FLAG_SETFD was set during notify_addfd
114 * @ret: The return value of the installing process. It is set to the fd num
115 * upon success (>= 0).
116 * @completion: Indicates that the installing process has completed fd
117 * installation, or gone away (either due to successful
119 * @list: list_head for chaining seccomp_kaddfd together.
122 struct seccomp_kaddfd
{
130 /* To only be set on reply */
133 struct completion completion
;
134 struct list_head list
;
138 * struct notification - container for seccomp userspace notifications. Since
139 * most seccomp filters will not have notification listeners attached and this
140 * structure is fairly large, we store the notification-specific stuff in a
141 * separate structure.
143 * @requests: A semaphore that users of this notification can wait on for
144 * changes. Actual reads and writes are still controlled with
145 * filter->notify_lock.
146 * @flags: A set of SECCOMP_USER_NOTIF_FD_* flags.
147 * @next_id: The id of the next request.
148 * @notifications: A list of struct seccomp_knotif elements.
151 struct notification
{
155 struct list_head notifications
;
158 #ifdef SECCOMP_ARCH_NATIVE
160 * struct action_cache - per-filter cache of seccomp actions per
163 * @allow_native: A bitmap where each bit represents whether the
164 * filter will always allow the syscall, for the
165 * native architecture.
166 * @allow_compat: A bitmap where each bit represents whether the
167 * filter will always allow the syscall, for the
168 * compat architecture.
170 struct action_cache
{
171 DECLARE_BITMAP(allow_native
, SECCOMP_ARCH_NATIVE_NR
);
172 #ifdef SECCOMP_ARCH_COMPAT
173 DECLARE_BITMAP(allow_compat
, SECCOMP_ARCH_COMPAT_NR
);
177 struct action_cache
{ };
179 static inline bool seccomp_cache_check_allow(const struct seccomp_filter
*sfilter
,
180 const struct seccomp_data
*sd
)
185 static inline void seccomp_cache_prepare(struct seccomp_filter
*sfilter
)
188 #endif /* SECCOMP_ARCH_NATIVE */
191 * struct seccomp_filter - container for seccomp BPF programs
193 * @refs: Reference count to manage the object lifetime.
194 * A filter's reference count is incremented for each directly
195 * attached task, once for the dependent filter, and if
196 * requested for the user notifier. When @refs reaches zero,
197 * the filter can be freed.
198 * @users: A filter's @users count is incremented for each directly
199 * attached task (filter installation, fork(), thread_sync),
200 * and once for the dependent filter (tracked in filter->prev).
201 * When it reaches zero it indicates that no direct or indirect
202 * users of that filter exist. No new tasks can get associated with
203 * this filter after reaching 0. The @users count is always smaller
204 * or equal to @refs. Hence, reaching 0 for @users does not mean
205 * the filter can be freed.
206 * @cache: cache of arch/syscall mappings to actions
207 * @log: true if all actions except for SECCOMP_RET_ALLOW should be logged
208 * @wait_killable_recv: Put notifying process in killable state once the
209 * notification is received by the userspace listener.
210 * @prev: points to a previously installed, or inherited, filter
211 * @prog: the BPF program to evaluate
212 * @notif: the struct that holds all notification related information
213 * @notify_lock: A lock for all notification-related accesses.
214 * @wqh: A wait queue for poll if a notifier is in use.
216 * seccomp_filter objects are organized in a tree linked via the @prev
217 * pointer. For any task, it appears to be a singly-linked list starting
218 * with current->seccomp.filter, the most recently attached or inherited filter.
219 * However, multiple filters may share a @prev node, by way of fork(), which
220 * results in a unidirectional tree existing in memory. This is similar to
221 * how namespaces work.
223 * seccomp_filter objects should never be modified after being attached
224 * to a task_struct (other than @refs).
226 struct seccomp_filter
{
230 bool wait_killable_recv
;
231 struct action_cache cache
;
232 struct seccomp_filter
*prev
;
233 struct bpf_prog
*prog
;
234 struct notification
*notif
;
235 struct mutex notify_lock
;
236 wait_queue_head_t wqh
;
239 /* Limit any path through the tree to 256KB worth of instructions. */
240 #define MAX_INSNS_PER_PATH ((1 << 18) / sizeof(struct sock_filter))
243 * Endianness is explicitly ignored and left for BPF program authors to manage
244 * as per the specific architecture.
246 static void populate_seccomp_data(struct seccomp_data
*sd
)
249 * Instead of using current_pt_reg(), we're already doing the work
250 * to safely fetch "current", so just use "task" everywhere below.
252 struct task_struct
*task
= current
;
253 struct pt_regs
*regs
= task_pt_regs(task
);
254 unsigned long args
[6];
256 sd
->nr
= syscall_get_nr(task
, regs
);
257 sd
->arch
= syscall_get_arch(task
);
258 syscall_get_arguments(task
, regs
, args
);
259 sd
->args
[0] = args
[0];
260 sd
->args
[1] = args
[1];
261 sd
->args
[2] = args
[2];
262 sd
->args
[3] = args
[3];
263 sd
->args
[4] = args
[4];
264 sd
->args
[5] = args
[5];
265 sd
->instruction_pointer
= KSTK_EIP(task
);
269 * seccomp_check_filter - verify seccomp filter code
270 * @filter: filter to verify
271 * @flen: length of filter
273 * Takes a previously checked filter (by bpf_check_classic) and
274 * redirects all filter code that loads struct sk_buff data
275 * and related data through seccomp_bpf_load. It also
276 * enforces length and alignment checking of those loads.
278 * Returns 0 if the rule set is legal or -EINVAL if not.
280 static int seccomp_check_filter(struct sock_filter
*filter
, unsigned int flen
)
283 for (pc
= 0; pc
< flen
; pc
++) {
284 struct sock_filter
*ftest
= &filter
[pc
];
285 u16 code
= ftest
->code
;
289 case BPF_LD
| BPF_W
| BPF_ABS
:
290 ftest
->code
= BPF_LDX
| BPF_W
| BPF_ABS
;
291 /* 32-bit aligned and not out of bounds. */
292 if (k
>= sizeof(struct seccomp_data
) || k
& 3)
295 case BPF_LD
| BPF_W
| BPF_LEN
:
296 ftest
->code
= BPF_LD
| BPF_IMM
;
297 ftest
->k
= sizeof(struct seccomp_data
);
299 case BPF_LDX
| BPF_W
| BPF_LEN
:
300 ftest
->code
= BPF_LDX
| BPF_IMM
;
301 ftest
->k
= sizeof(struct seccomp_data
);
303 /* Explicitly include allowed calls. */
304 case BPF_RET
| BPF_K
:
305 case BPF_RET
| BPF_A
:
306 case BPF_ALU
| BPF_ADD
| BPF_K
:
307 case BPF_ALU
| BPF_ADD
| BPF_X
:
308 case BPF_ALU
| BPF_SUB
| BPF_K
:
309 case BPF_ALU
| BPF_SUB
| BPF_X
:
310 case BPF_ALU
| BPF_MUL
| BPF_K
:
311 case BPF_ALU
| BPF_MUL
| BPF_X
:
312 case BPF_ALU
| BPF_DIV
| BPF_K
:
313 case BPF_ALU
| BPF_DIV
| BPF_X
:
314 case BPF_ALU
| BPF_AND
| BPF_K
:
315 case BPF_ALU
| BPF_AND
| BPF_X
:
316 case BPF_ALU
| BPF_OR
| BPF_K
:
317 case BPF_ALU
| BPF_OR
| BPF_X
:
318 case BPF_ALU
| BPF_XOR
| BPF_K
:
319 case BPF_ALU
| BPF_XOR
| BPF_X
:
320 case BPF_ALU
| BPF_LSH
| BPF_K
:
321 case BPF_ALU
| BPF_LSH
| BPF_X
:
322 case BPF_ALU
| BPF_RSH
| BPF_K
:
323 case BPF_ALU
| BPF_RSH
| BPF_X
:
324 case BPF_ALU
| BPF_NEG
:
325 case BPF_LD
| BPF_IMM
:
326 case BPF_LDX
| BPF_IMM
:
327 case BPF_MISC
| BPF_TAX
:
328 case BPF_MISC
| BPF_TXA
:
329 case BPF_LD
| BPF_MEM
:
330 case BPF_LDX
| BPF_MEM
:
333 case BPF_JMP
| BPF_JA
:
334 case BPF_JMP
| BPF_JEQ
| BPF_K
:
335 case BPF_JMP
| BPF_JEQ
| BPF_X
:
336 case BPF_JMP
| BPF_JGE
| BPF_K
:
337 case BPF_JMP
| BPF_JGE
| BPF_X
:
338 case BPF_JMP
| BPF_JGT
| BPF_K
:
339 case BPF_JMP
| BPF_JGT
| BPF_X
:
340 case BPF_JMP
| BPF_JSET
| BPF_K
:
341 case BPF_JMP
| BPF_JSET
| BPF_X
:
350 #ifdef SECCOMP_ARCH_NATIVE
351 static inline bool seccomp_cache_check_allow_bitmap(const void *bitmap
,
355 if (unlikely(syscall_nr
< 0 || syscall_nr
>= bitmap_size
))
357 syscall_nr
= array_index_nospec(syscall_nr
, bitmap_size
);
359 return test_bit(syscall_nr
, bitmap
);
363 * seccomp_cache_check_allow - lookup seccomp cache
364 * @sfilter: The seccomp filter
365 * @sd: The seccomp data to lookup the cache with
367 * Returns true if the seccomp_data is cached and allowed.
369 static inline bool seccomp_cache_check_allow(const struct seccomp_filter
*sfilter
,
370 const struct seccomp_data
*sd
)
372 int syscall_nr
= sd
->nr
;
373 const struct action_cache
*cache
= &sfilter
->cache
;
375 #ifndef SECCOMP_ARCH_COMPAT
376 /* A native-only architecture doesn't need to check sd->arch. */
377 return seccomp_cache_check_allow_bitmap(cache
->allow_native
,
378 SECCOMP_ARCH_NATIVE_NR
,
381 if (likely(sd
->arch
== SECCOMP_ARCH_NATIVE
))
382 return seccomp_cache_check_allow_bitmap(cache
->allow_native
,
383 SECCOMP_ARCH_NATIVE_NR
,
385 if (likely(sd
->arch
== SECCOMP_ARCH_COMPAT
))
386 return seccomp_cache_check_allow_bitmap(cache
->allow_compat
,
387 SECCOMP_ARCH_COMPAT_NR
,
389 #endif /* SECCOMP_ARCH_COMPAT */
394 #endif /* SECCOMP_ARCH_NATIVE */
396 #define ACTION_ONLY(ret) ((s32)((ret) & (SECCOMP_RET_ACTION_FULL)))
398 * seccomp_run_filters - evaluates all seccomp filters against @sd
399 * @sd: optional seccomp data to be passed to filters
400 * @match: stores struct seccomp_filter that resulted in the return value,
401 * unless filter returned SECCOMP_RET_ALLOW, in which case it will
404 * Returns valid seccomp BPF response codes.
406 static u32
seccomp_run_filters(const struct seccomp_data
*sd
,
407 struct seccomp_filter
**match
)
409 u32 ret
= SECCOMP_RET_ALLOW
;
410 /* Make sure cross-thread synced filter points somewhere sane. */
411 struct seccomp_filter
*f
=
412 READ_ONCE(current
->seccomp
.filter
);
414 /* Ensure unexpected behavior doesn't result in failing open. */
415 if (WARN_ON(f
== NULL
))
416 return SECCOMP_RET_KILL_PROCESS
;
418 if (seccomp_cache_check_allow(f
, sd
))
419 return SECCOMP_RET_ALLOW
;
422 * All filters in the list are evaluated and the lowest BPF return
423 * value always takes priority (ignoring the DATA).
425 for (; f
; f
= f
->prev
) {
426 u32 cur_ret
= bpf_prog_run_pin_on_cpu(f
->prog
, sd
);
428 if (ACTION_ONLY(cur_ret
) < ACTION_ONLY(ret
)) {
435 #endif /* CONFIG_SECCOMP_FILTER */
437 static inline bool seccomp_may_assign_mode(unsigned long seccomp_mode
)
439 assert_spin_locked(¤t
->sighand
->siglock
);
441 if (current
->seccomp
.mode
&& current
->seccomp
.mode
!= seccomp_mode
)
447 void __weak
arch_seccomp_spec_mitigate(struct task_struct
*task
) { }
449 static inline void seccomp_assign_mode(struct task_struct
*task
,
450 unsigned long seccomp_mode
,
453 assert_spin_locked(&task
->sighand
->siglock
);
455 task
->seccomp
.mode
= seccomp_mode
;
457 * Make sure SYSCALL_WORK_SECCOMP cannot be set before the mode (and
460 smp_mb__before_atomic();
461 /* Assume default seccomp processes want spec flaw mitigation. */
462 if ((flags
& SECCOMP_FILTER_FLAG_SPEC_ALLOW
) == 0)
463 arch_seccomp_spec_mitigate(task
);
464 set_task_syscall_work(task
, SECCOMP
);
467 #ifdef CONFIG_SECCOMP_FILTER
468 /* Returns 1 if the parent is an ancestor of the child. */
469 static int is_ancestor(struct seccomp_filter
*parent
,
470 struct seccomp_filter
*child
)
472 /* NULL is the root ancestor. */
475 for (; child
; child
= child
->prev
)
482 * seccomp_can_sync_threads: checks if all threads can be synchronized
484 * Expects sighand and cred_guard_mutex locks to be held.
486 * Returns 0 on success, -ve on error, or the pid of a thread which was
487 * either not in the correct seccomp mode or did not have an ancestral
490 static inline pid_t
seccomp_can_sync_threads(void)
492 struct task_struct
*thread
, *caller
;
494 BUG_ON(!mutex_is_locked(¤t
->signal
->cred_guard_mutex
));
495 assert_spin_locked(¤t
->sighand
->siglock
);
497 /* Validate all threads being eligible for synchronization. */
499 for_each_thread(caller
, thread
) {
502 /* Skip current, since it is initiating the sync. */
503 if (thread
== caller
)
506 if (thread
->seccomp
.mode
== SECCOMP_MODE_DISABLED
||
507 (thread
->seccomp
.mode
== SECCOMP_MODE_FILTER
&&
508 is_ancestor(thread
->seccomp
.filter
,
509 caller
->seccomp
.filter
)))
512 /* Return the first thread that cannot be synchronized. */
513 failed
= task_pid_vnr(thread
);
514 /* If the pid cannot be resolved, then return -ESRCH */
515 if (WARN_ON(failed
== 0))
523 static inline void seccomp_filter_free(struct seccomp_filter
*filter
)
526 bpf_prog_destroy(filter
->prog
);
531 static void __seccomp_filter_orphan(struct seccomp_filter
*orig
)
533 while (orig
&& refcount_dec_and_test(&orig
->users
)) {
534 if (waitqueue_active(&orig
->wqh
))
535 wake_up_poll(&orig
->wqh
, EPOLLHUP
);
540 static void __put_seccomp_filter(struct seccomp_filter
*orig
)
542 /* Clean up single-reference branches iteratively. */
543 while (orig
&& refcount_dec_and_test(&orig
->refs
)) {
544 struct seccomp_filter
*freeme
= orig
;
546 seccomp_filter_free(freeme
);
550 static void __seccomp_filter_release(struct seccomp_filter
*orig
)
552 /* Notify about any unused filters in the task's former filter tree. */
553 __seccomp_filter_orphan(orig
);
554 /* Finally drop all references to the task's former tree. */
555 __put_seccomp_filter(orig
);
559 * seccomp_filter_release - Detach the task from its filter tree,
560 * drop its reference count, and notify
561 * about unused filters
563 * @tsk: task the filter should be released from.
565 * This function should only be called when the task is exiting as
566 * it detaches it from its filter tree. As such, READ_ONCE() and
567 * barriers are not needed here, as would normally be needed.
569 void seccomp_filter_release(struct task_struct
*tsk
)
571 struct seccomp_filter
*orig
= tsk
->seccomp
.filter
;
573 /* We are effectively holding the siglock by not having any sighand. */
574 WARN_ON(tsk
->sighand
!= NULL
);
576 /* Detach task from its filter tree. */
577 tsk
->seccomp
.filter
= NULL
;
578 __seccomp_filter_release(orig
);
582 * seccomp_sync_threads: sets all threads to use current's filter
584 * @flags: SECCOMP_FILTER_FLAG_* flags to set during sync.
586 * Expects sighand and cred_guard_mutex locks to be held, and for
587 * seccomp_can_sync_threads() to have returned success already
588 * without dropping the locks.
591 static inline void seccomp_sync_threads(unsigned long flags
)
593 struct task_struct
*thread
, *caller
;
595 BUG_ON(!mutex_is_locked(¤t
->signal
->cred_guard_mutex
));
596 assert_spin_locked(¤t
->sighand
->siglock
);
598 /* Synchronize all threads. */
600 for_each_thread(caller
, thread
) {
601 /* Skip current, since it needs no changes. */
602 if (thread
== caller
)
605 /* Get a task reference for the new leaf node. */
606 get_seccomp_filter(caller
);
609 * Drop the task reference to the shared ancestor since
610 * current's path will hold a reference. (This also
611 * allows a put before the assignment.)
613 __seccomp_filter_release(thread
->seccomp
.filter
);
615 /* Make our new filter tree visible. */
616 smp_store_release(&thread
->seccomp
.filter
,
617 caller
->seccomp
.filter
);
618 atomic_set(&thread
->seccomp
.filter_count
,
619 atomic_read(&caller
->seccomp
.filter_count
));
622 * Don't let an unprivileged task work around
623 * the no_new_privs restriction by creating
624 * a thread that sets it up, enters seccomp,
627 if (task_no_new_privs(caller
))
628 task_set_no_new_privs(thread
);
631 * Opt the other thread into seccomp if needed.
632 * As threads are considered to be trust-realm
633 * equivalent (see ptrace_may_access), it is safe to
634 * allow one thread to transition the other.
636 if (thread
->seccomp
.mode
== SECCOMP_MODE_DISABLED
)
637 seccomp_assign_mode(thread
, SECCOMP_MODE_FILTER
,
643 * seccomp_prepare_filter: Prepares a seccomp filter for use.
644 * @fprog: BPF program to install
646 * Returns filter on success or an ERR_PTR on failure.
648 static struct seccomp_filter
*seccomp_prepare_filter(struct sock_fprog
*fprog
)
650 struct seccomp_filter
*sfilter
;
652 const bool save_orig
=
653 #if defined(CONFIG_CHECKPOINT_RESTORE) || defined(SECCOMP_ARCH_NATIVE)
659 if (fprog
->len
== 0 || fprog
->len
> BPF_MAXINSNS
)
660 return ERR_PTR(-EINVAL
);
662 BUG_ON(INT_MAX
/ fprog
->len
< sizeof(struct sock_filter
));
665 * Installing a seccomp filter requires that the task has
666 * CAP_SYS_ADMIN in its namespace or be running with no_new_privs.
667 * This avoids scenarios where unprivileged tasks can affect the
668 * behavior of privileged children.
670 if (!task_no_new_privs(current
) &&
671 !ns_capable_noaudit(current_user_ns(), CAP_SYS_ADMIN
))
672 return ERR_PTR(-EACCES
);
674 /* Allocate a new seccomp_filter */
675 sfilter
= kzalloc(sizeof(*sfilter
), GFP_KERNEL
| __GFP_NOWARN
);
677 return ERR_PTR(-ENOMEM
);
679 mutex_init(&sfilter
->notify_lock
);
680 ret
= bpf_prog_create_from_user(&sfilter
->prog
, fprog
,
681 seccomp_check_filter
, save_orig
);
687 refcount_set(&sfilter
->refs
, 1);
688 refcount_set(&sfilter
->users
, 1);
689 init_waitqueue_head(&sfilter
->wqh
);
695 * seccomp_prepare_user_filter - prepares a user-supplied sock_fprog
696 * @user_filter: pointer to the user data containing a sock_fprog.
698 * Returns 0 on success and non-zero otherwise.
700 static struct seccomp_filter
*
701 seccomp_prepare_user_filter(const char __user
*user_filter
)
703 struct sock_fprog fprog
;
704 struct seccomp_filter
*filter
= ERR_PTR(-EFAULT
);
707 if (in_compat_syscall()) {
708 struct compat_sock_fprog fprog32
;
709 if (copy_from_user(&fprog32
, user_filter
, sizeof(fprog32
)))
711 fprog
.len
= fprog32
.len
;
712 fprog
.filter
= compat_ptr(fprog32
.filter
);
713 } else /* falls through to the if below. */
715 if (copy_from_user(&fprog
, user_filter
, sizeof(fprog
)))
717 filter
= seccomp_prepare_filter(&fprog
);
722 #ifdef SECCOMP_ARCH_NATIVE
724 * seccomp_is_const_allow - check if filter is constant allow with given data
725 * @fprog: The BPF programs
726 * @sd: The seccomp data to check against, only syscall number and arch
727 * number are considered constant.
729 static bool seccomp_is_const_allow(struct sock_fprog_kern
*fprog
,
730 struct seccomp_data
*sd
)
732 unsigned int reg_value
= 0;
736 if (WARN_ON_ONCE(!fprog
))
739 for (pc
= 0; pc
< fprog
->len
; pc
++) {
740 struct sock_filter
*insn
= &fprog
->filter
[pc
];
741 u16 code
= insn
->code
;
745 case BPF_LD
| BPF_W
| BPF_ABS
:
747 case offsetof(struct seccomp_data
, nr
):
750 case offsetof(struct seccomp_data
, arch
):
751 reg_value
= sd
->arch
;
754 /* can't optimize (non-constant value load) */
758 case BPF_RET
| BPF_K
:
759 /* reached return with constant values only, check allow */
760 return k
== SECCOMP_RET_ALLOW
;
761 case BPF_JMP
| BPF_JA
:
764 case BPF_JMP
| BPF_JEQ
| BPF_K
:
765 case BPF_JMP
| BPF_JGE
| BPF_K
:
766 case BPF_JMP
| BPF_JGT
| BPF_K
:
767 case BPF_JMP
| BPF_JSET
| BPF_K
:
768 switch (BPF_OP(code
)) {
770 op_res
= reg_value
== k
;
773 op_res
= reg_value
>= k
;
776 op_res
= reg_value
> k
;
779 op_res
= !!(reg_value
& k
);
782 /* can't optimize (unknown jump) */
786 pc
+= op_res
? insn
->jt
: insn
->jf
;
788 case BPF_ALU
| BPF_AND
| BPF_K
:
792 /* can't optimize (unknown insn) */
797 /* ran off the end of the filter?! */
802 static void seccomp_cache_prepare_bitmap(struct seccomp_filter
*sfilter
,
803 void *bitmap
, const void *bitmap_prev
,
804 size_t bitmap_size
, int arch
)
806 struct sock_fprog_kern
*fprog
= sfilter
->prog
->orig_prog
;
807 struct seccomp_data sd
;
811 /* The new filter must be as restrictive as the last. */
812 bitmap_copy(bitmap
, bitmap_prev
, bitmap_size
);
814 /* Before any filters, all syscalls are always allowed. */
815 bitmap_fill(bitmap
, bitmap_size
);
818 for (nr
= 0; nr
< bitmap_size
; nr
++) {
819 /* No bitmap change: not a cacheable action. */
820 if (!test_bit(nr
, bitmap
))
826 /* No bitmap change: continue to always allow. */
827 if (seccomp_is_const_allow(fprog
, &sd
))
831 * Not a cacheable action: always run filters.
832 * atomic clear_bit() not needed, filter not visible yet.
834 __clear_bit(nr
, bitmap
);
839 * seccomp_cache_prepare - emulate the filter to find cacheable syscalls
840 * @sfilter: The seccomp filter
842 * Returns 0 if successful or -errno if error occurred.
844 static void seccomp_cache_prepare(struct seccomp_filter
*sfilter
)
846 struct action_cache
*cache
= &sfilter
->cache
;
847 const struct action_cache
*cache_prev
=
848 sfilter
->prev
? &sfilter
->prev
->cache
: NULL
;
850 seccomp_cache_prepare_bitmap(sfilter
, cache
->allow_native
,
851 cache_prev
? cache_prev
->allow_native
: NULL
,
852 SECCOMP_ARCH_NATIVE_NR
,
853 SECCOMP_ARCH_NATIVE
);
855 #ifdef SECCOMP_ARCH_COMPAT
856 seccomp_cache_prepare_bitmap(sfilter
, cache
->allow_compat
,
857 cache_prev
? cache_prev
->allow_compat
: NULL
,
858 SECCOMP_ARCH_COMPAT_NR
,
859 SECCOMP_ARCH_COMPAT
);
860 #endif /* SECCOMP_ARCH_COMPAT */
862 #endif /* SECCOMP_ARCH_NATIVE */
865 * seccomp_attach_filter: validate and attach filter
866 * @flags: flags to change filter behavior
867 * @filter: seccomp filter to add to the current process
869 * Caller must be holding current->sighand->siglock lock.
871 * Returns 0 on success, -ve on error, or
872 * - in TSYNC mode: the pid of a thread which was either not in the correct
873 * seccomp mode or did not have an ancestral seccomp filter
874 * - in NEW_LISTENER mode: the fd of the new listener
876 static long seccomp_attach_filter(unsigned int flags
,
877 struct seccomp_filter
*filter
)
879 unsigned long total_insns
;
880 struct seccomp_filter
*walker
;
882 assert_spin_locked(¤t
->sighand
->siglock
);
884 /* Validate resulting filter length. */
885 total_insns
= filter
->prog
->len
;
886 for (walker
= current
->seccomp
.filter
; walker
; walker
= walker
->prev
)
887 total_insns
+= walker
->prog
->len
+ 4; /* 4 instr penalty */
888 if (total_insns
> MAX_INSNS_PER_PATH
)
891 /* If thread sync has been requested, check that it is possible. */
892 if (flags
& SECCOMP_FILTER_FLAG_TSYNC
) {
895 ret
= seccomp_can_sync_threads();
897 if (flags
& SECCOMP_FILTER_FLAG_TSYNC_ESRCH
)
904 /* Set log flag, if present. */
905 if (flags
& SECCOMP_FILTER_FLAG_LOG
)
908 /* Set wait killable flag, if present. */
909 if (flags
& SECCOMP_FILTER_FLAG_WAIT_KILLABLE_RECV
)
910 filter
->wait_killable_recv
= true;
913 * If there is an existing filter, make it the prev and don't drop its
916 filter
->prev
= current
->seccomp
.filter
;
917 seccomp_cache_prepare(filter
);
918 current
->seccomp
.filter
= filter
;
919 atomic_inc(¤t
->seccomp
.filter_count
);
921 /* Now that the new filter is in place, synchronize to all threads. */
922 if (flags
& SECCOMP_FILTER_FLAG_TSYNC
)
923 seccomp_sync_threads(flags
);
928 static void __get_seccomp_filter(struct seccomp_filter
*filter
)
930 refcount_inc(&filter
->refs
);
933 /* get_seccomp_filter - increments the reference count of the filter on @tsk */
934 void get_seccomp_filter(struct task_struct
*tsk
)
936 struct seccomp_filter
*orig
= tsk
->seccomp
.filter
;
939 __get_seccomp_filter(orig
);
940 refcount_inc(&orig
->users
);
943 #endif /* CONFIG_SECCOMP_FILTER */
945 /* For use with seccomp_actions_logged */
946 #define SECCOMP_LOG_KILL_PROCESS (1 << 0)
947 #define SECCOMP_LOG_KILL_THREAD (1 << 1)
948 #define SECCOMP_LOG_TRAP (1 << 2)
949 #define SECCOMP_LOG_ERRNO (1 << 3)
950 #define SECCOMP_LOG_TRACE (1 << 4)
951 #define SECCOMP_LOG_LOG (1 << 5)
952 #define SECCOMP_LOG_ALLOW (1 << 6)
953 #define SECCOMP_LOG_USER_NOTIF (1 << 7)
955 static u32 seccomp_actions_logged
= SECCOMP_LOG_KILL_PROCESS
|
956 SECCOMP_LOG_KILL_THREAD
|
959 SECCOMP_LOG_USER_NOTIF
|
963 static inline void seccomp_log(unsigned long syscall
, long signr
, u32 action
,
969 case SECCOMP_RET_ALLOW
:
971 case SECCOMP_RET_TRAP
:
972 log
= requested
&& seccomp_actions_logged
& SECCOMP_LOG_TRAP
;
974 case SECCOMP_RET_ERRNO
:
975 log
= requested
&& seccomp_actions_logged
& SECCOMP_LOG_ERRNO
;
977 case SECCOMP_RET_TRACE
:
978 log
= requested
&& seccomp_actions_logged
& SECCOMP_LOG_TRACE
;
980 case SECCOMP_RET_USER_NOTIF
:
981 log
= requested
&& seccomp_actions_logged
& SECCOMP_LOG_USER_NOTIF
;
983 case SECCOMP_RET_LOG
:
984 log
= seccomp_actions_logged
& SECCOMP_LOG_LOG
;
986 case SECCOMP_RET_KILL_THREAD
:
987 log
= seccomp_actions_logged
& SECCOMP_LOG_KILL_THREAD
;
989 case SECCOMP_RET_KILL_PROCESS
:
991 log
= seccomp_actions_logged
& SECCOMP_LOG_KILL_PROCESS
;
995 * Emit an audit message when the action is RET_KILL_*, RET_LOG, or the
996 * FILTER_FLAG_LOG bit was set. The admin has the ability to silence
997 * any action from being logged by removing the action name from the
998 * seccomp_actions_logged sysctl.
1003 audit_seccomp(syscall
, signr
, action
);
1007 * Secure computing mode 1 allows only read/write/exit/sigreturn.
1008 * To be fully secure this must be combined with rlimit
1009 * to limit the stack allocations too.
1011 static const int mode1_syscalls
[] = {
1012 __NR_seccomp_read
, __NR_seccomp_write
, __NR_seccomp_exit
, __NR_seccomp_sigreturn
,
1013 -1, /* negative terminated */
1016 static void __secure_computing_strict(int this_syscall
)
1018 const int *allowed_syscalls
= mode1_syscalls
;
1019 #ifdef CONFIG_COMPAT
1020 if (in_compat_syscall())
1021 allowed_syscalls
= get_compat_mode1_syscalls();
1024 if (*allowed_syscalls
== this_syscall
)
1026 } while (*++allowed_syscalls
!= -1);
1028 #ifdef SECCOMP_DEBUG
1031 current
->seccomp
.mode
= SECCOMP_MODE_DEAD
;
1032 seccomp_log(this_syscall
, SIGKILL
, SECCOMP_RET_KILL_THREAD
, true);
1036 #ifndef CONFIG_HAVE_ARCH_SECCOMP_FILTER
1037 void secure_computing_strict(int this_syscall
)
1039 int mode
= current
->seccomp
.mode
;
1041 if (IS_ENABLED(CONFIG_CHECKPOINT_RESTORE
) &&
1042 unlikely(current
->ptrace
& PT_SUSPEND_SECCOMP
))
1045 if (mode
== SECCOMP_MODE_DISABLED
)
1047 else if (mode
== SECCOMP_MODE_STRICT
)
1048 __secure_computing_strict(this_syscall
);
1054 #ifdef CONFIG_SECCOMP_FILTER
1055 static u64
seccomp_next_notify_id(struct seccomp_filter
*filter
)
1058 * Note: overflow is ok here, the id just needs to be unique per
1061 lockdep_assert_held(&filter
->notify_lock
);
1062 return filter
->notif
->next_id
++;
1065 static void seccomp_handle_addfd(struct seccomp_kaddfd
*addfd
, struct seccomp_knotif
*n
)
1070 * Remove the notification, and reset the list pointers, indicating
1071 * that it has been handled.
1073 list_del_init(&addfd
->list
);
1075 fd
= receive_fd(addfd
->file
, addfd
->flags
);
1077 fd
= receive_fd_replace(addfd
->fd
, addfd
->file
, addfd
->flags
);
1080 if (addfd
->ioctl_flags
& SECCOMP_ADDFD_FLAG_SEND
) {
1081 /* If we fail reset and return an error to the notifier */
1083 n
->state
= SECCOMP_NOTIFY_SENT
;
1085 /* Return the FD we just added */
1093 * Mark the notification as completed. From this point, addfd mem
1094 * might be invalidated and we can't safely read it anymore.
1096 complete(&addfd
->completion
);
1099 static bool should_sleep_killable(struct seccomp_filter
*match
,
1100 struct seccomp_knotif
*n
)
1102 return match
->wait_killable_recv
&& n
->state
== SECCOMP_NOTIFY_SENT
;
1105 static int seccomp_do_user_notification(int this_syscall
,
1106 struct seccomp_filter
*match
,
1107 const struct seccomp_data
*sd
)
1112 struct seccomp_knotif n
= {};
1113 struct seccomp_kaddfd
*addfd
, *tmp
;
1115 mutex_lock(&match
->notify_lock
);
1121 n
.state
= SECCOMP_NOTIFY_INIT
;
1123 n
.id
= seccomp_next_notify_id(match
);
1124 init_completion(&n
.ready
);
1125 list_add_tail(&n
.list
, &match
->notif
->notifications
);
1126 INIT_LIST_HEAD(&n
.addfd
);
1128 atomic_inc(&match
->notif
->requests
);
1129 if (match
->notif
->flags
& SECCOMP_USER_NOTIF_FD_SYNC_WAKE_UP
)
1130 wake_up_poll_on_current_cpu(&match
->wqh
, EPOLLIN
| EPOLLRDNORM
);
1132 wake_up_poll(&match
->wqh
, EPOLLIN
| EPOLLRDNORM
);
1135 * This is where we wait for a reply from userspace.
1138 bool wait_killable
= should_sleep_killable(match
, &n
);
1140 mutex_unlock(&match
->notify_lock
);
1142 err
= wait_for_completion_killable(&n
.ready
);
1144 err
= wait_for_completion_interruptible(&n
.ready
);
1145 mutex_lock(&match
->notify_lock
);
1149 * Check to see if the notifcation got picked up and
1150 * whether we should switch to wait killable.
1152 if (!wait_killable
&& should_sleep_killable(match
, &n
))
1158 addfd
= list_first_entry_or_null(&n
.addfd
,
1159 struct seccomp_kaddfd
, list
);
1160 /* Check if we were woken up by a addfd message */
1162 seccomp_handle_addfd(addfd
, &n
);
1164 } while (n
.state
!= SECCOMP_NOTIFY_REPLIED
);
1171 /* If there were any pending addfd calls, clear them out */
1172 list_for_each_entry_safe(addfd
, tmp
, &n
.addfd
, list
) {
1173 /* The process went away before we got a chance to handle it */
1174 addfd
->ret
= -ESRCH
;
1175 list_del_init(&addfd
->list
);
1176 complete(&addfd
->completion
);
1180 * Note that it's possible the listener died in between the time when
1181 * we were notified of a response (or a signal) and when we were able to
1182 * re-acquire the lock, so only delete from the list if the
1183 * notification actually exists.
1185 * Also note that this test is only valid because there's no way to
1186 * *reattach* to a notifier right now. If one is added, we'll need to
1187 * keep track of the notif itself and make sure they match here.
1192 mutex_unlock(&match
->notify_lock
);
1194 /* Userspace requests to continue the syscall. */
1195 if (flags
& SECCOMP_USER_NOTIF_FLAG_CONTINUE
)
1198 syscall_set_return_value(current
, current_pt_regs(),
1203 static int __seccomp_filter(int this_syscall
, const struct seccomp_data
*sd
,
1204 const bool recheck_after_trace
)
1206 u32 filter_ret
, action
;
1207 struct seccomp_filter
*match
= NULL
;
1209 struct seccomp_data sd_local
;
1212 * Make sure that any changes to mode from another thread have
1213 * been seen after SYSCALL_WORK_SECCOMP was seen.
1218 populate_seccomp_data(&sd_local
);
1222 filter_ret
= seccomp_run_filters(sd
, &match
);
1223 data
= filter_ret
& SECCOMP_RET_DATA
;
1224 action
= filter_ret
& SECCOMP_RET_ACTION_FULL
;
1227 case SECCOMP_RET_ERRNO
:
1228 /* Set low-order bits as an errno, capped at MAX_ERRNO. */
1229 if (data
> MAX_ERRNO
)
1231 syscall_set_return_value(current
, current_pt_regs(),
1235 case SECCOMP_RET_TRAP
:
1236 /* Show the handler the original registers. */
1237 syscall_rollback(current
, current_pt_regs());
1238 /* Let the filter pass back 16 bits of data. */
1239 force_sig_seccomp(this_syscall
, data
, false);
1242 case SECCOMP_RET_TRACE
:
1243 /* We've been put in this state by the ptracer already. */
1244 if (recheck_after_trace
)
1247 /* ENOSYS these calls if there is no tracer attached. */
1248 if (!ptrace_event_enabled(current
, PTRACE_EVENT_SECCOMP
)) {
1249 syscall_set_return_value(current
,
1255 /* Allow the BPF to provide the event message */
1256 ptrace_event(PTRACE_EVENT_SECCOMP
, data
);
1258 * The delivery of a fatal signal during event
1259 * notification may silently skip tracer notification,
1260 * which could leave us with a potentially unmodified
1261 * syscall that the tracer would have liked to have
1262 * changed. Since the process is about to die, we just
1263 * force the syscall to be skipped and let the signal
1264 * kill the process and correctly handle any tracer exit
1267 if (fatal_signal_pending(current
))
1269 /* Check if the tracer forced the syscall to be skipped. */
1270 this_syscall
= syscall_get_nr(current
, current_pt_regs());
1271 if (this_syscall
< 0)
1275 * Recheck the syscall, since it may have changed. This
1276 * intentionally uses a NULL struct seccomp_data to force
1277 * a reload of all registers. This does not goto skip since
1278 * a skip would have already been reported.
1280 if (__seccomp_filter(this_syscall
, NULL
, true))
1285 case SECCOMP_RET_USER_NOTIF
:
1286 if (seccomp_do_user_notification(this_syscall
, match
, sd
))
1291 case SECCOMP_RET_LOG
:
1292 seccomp_log(this_syscall
, 0, action
, true);
1295 case SECCOMP_RET_ALLOW
:
1297 * Note that the "match" filter will always be NULL for
1298 * this action since SECCOMP_RET_ALLOW is the starting
1299 * state in seccomp_run_filters().
1303 case SECCOMP_RET_KILL_THREAD
:
1304 case SECCOMP_RET_KILL_PROCESS
:
1306 current
->seccomp
.mode
= SECCOMP_MODE_DEAD
;
1307 seccomp_log(this_syscall
, SIGSYS
, action
, true);
1308 /* Dump core only if this is the last remaining thread. */
1309 if (action
!= SECCOMP_RET_KILL_THREAD
||
1310 (atomic_read(¤t
->signal
->live
) == 1)) {
1311 /* Show the original registers in the dump. */
1312 syscall_rollback(current
, current_pt_regs());
1313 /* Trigger a coredump with SIGSYS */
1314 force_sig_seccomp(this_syscall
, data
, true);
1318 return -1; /* skip the syscall go directly to signal handling */
1324 seccomp_log(this_syscall
, 0, action
, match
? match
->log
: false);
1328 static int __seccomp_filter(int this_syscall
, const struct seccomp_data
*sd
,
1329 const bool recheck_after_trace
)
1337 int __secure_computing(const struct seccomp_data
*sd
)
1339 int mode
= current
->seccomp
.mode
;
1342 if (IS_ENABLED(CONFIG_CHECKPOINT_RESTORE
) &&
1343 unlikely(current
->ptrace
& PT_SUSPEND_SECCOMP
))
1346 this_syscall
= sd
? sd
->nr
:
1347 syscall_get_nr(current
, current_pt_regs());
1350 case SECCOMP_MODE_STRICT
:
1351 __secure_computing_strict(this_syscall
); /* may call do_exit */
1353 case SECCOMP_MODE_FILTER
:
1354 return __seccomp_filter(this_syscall
, sd
, false);
1355 /* Surviving SECCOMP_RET_KILL_* must be proactively impossible. */
1356 case SECCOMP_MODE_DEAD
:
1364 #endif /* CONFIG_HAVE_ARCH_SECCOMP_FILTER */
1366 long prctl_get_seccomp(void)
1368 return current
->seccomp
.mode
;
1372 * seccomp_set_mode_strict: internal function for setting strict seccomp
1374 * Once current->seccomp.mode is non-zero, it may not be changed.
1376 * Returns 0 on success or -EINVAL on failure.
1378 static long seccomp_set_mode_strict(void)
1380 const unsigned long seccomp_mode
= SECCOMP_MODE_STRICT
;
1383 spin_lock_irq(¤t
->sighand
->siglock
);
1385 if (!seccomp_may_assign_mode(seccomp_mode
))
1391 seccomp_assign_mode(current
, seccomp_mode
, 0);
1395 spin_unlock_irq(¤t
->sighand
->siglock
);
1400 #ifdef CONFIG_SECCOMP_FILTER
1401 static void seccomp_notify_free(struct seccomp_filter
*filter
)
1403 kfree(filter
->notif
);
1404 filter
->notif
= NULL
;
1407 static void seccomp_notify_detach(struct seccomp_filter
*filter
)
1409 struct seccomp_knotif
*knotif
;
1414 mutex_lock(&filter
->notify_lock
);
1417 * If this file is being closed because e.g. the task who owned it
1418 * died, let's wake everyone up who was waiting on us.
1420 list_for_each_entry(knotif
, &filter
->notif
->notifications
, list
) {
1421 if (knotif
->state
== SECCOMP_NOTIFY_REPLIED
)
1424 knotif
->state
= SECCOMP_NOTIFY_REPLIED
;
1425 knotif
->error
= -ENOSYS
;
1429 * We do not need to wake up any pending addfd messages, as
1430 * the notifier will do that for us, as this just looks
1431 * like a standard reply.
1433 complete(&knotif
->ready
);
1436 seccomp_notify_free(filter
);
1437 mutex_unlock(&filter
->notify_lock
);
1440 static int seccomp_notify_release(struct inode
*inode
, struct file
*file
)
1442 struct seccomp_filter
*filter
= file
->private_data
;
1444 seccomp_notify_detach(filter
);
1445 __put_seccomp_filter(filter
);
1449 /* must be called with notif_lock held */
1450 static inline struct seccomp_knotif
*
1451 find_notification(struct seccomp_filter
*filter
, u64 id
)
1453 struct seccomp_knotif
*cur
;
1455 lockdep_assert_held(&filter
->notify_lock
);
1457 list_for_each_entry(cur
, &filter
->notif
->notifications
, list
) {
1465 static int recv_wake_function(wait_queue_entry_t
*wait
, unsigned int mode
, int sync
,
1468 /* Avoid a wakeup if event not interesting for us. */
1469 if (key
&& !(key_to_poll(key
) & (EPOLLIN
| EPOLLERR
)))
1471 return autoremove_wake_function(wait
, mode
, sync
, key
);
1474 static int recv_wait_event(struct seccomp_filter
*filter
)
1476 DEFINE_WAIT_FUNC(wait
, recv_wake_function
);
1479 if (atomic_dec_if_positive(&filter
->notif
->requests
) >= 0)
1483 ret
= prepare_to_wait_event(&filter
->wqh
, &wait
, TASK_INTERRUPTIBLE
);
1485 if (atomic_dec_if_positive(&filter
->notif
->requests
) >= 0)
1493 finish_wait(&filter
->wqh
, &wait
);
1497 static long seccomp_notify_recv(struct seccomp_filter
*filter
,
1500 struct seccomp_knotif
*knotif
= NULL
, *cur
;
1501 struct seccomp_notif unotif
;
1504 /* Verify that we're not given garbage to keep struct extensible. */
1505 ret
= check_zeroed_user(buf
, sizeof(unotif
));
1511 memset(&unotif
, 0, sizeof(unotif
));
1513 ret
= recv_wait_event(filter
);
1517 mutex_lock(&filter
->notify_lock
);
1518 list_for_each_entry(cur
, &filter
->notif
->notifications
, list
) {
1519 if (cur
->state
== SECCOMP_NOTIFY_INIT
) {
1526 * If we didn't find a notification, it could be that the task was
1527 * interrupted by a fatal signal between the time we were woken and
1528 * when we were able to acquire the rw lock.
1535 unotif
.id
= knotif
->id
;
1536 unotif
.pid
= task_pid_vnr(knotif
->task
);
1537 unotif
.data
= *(knotif
->data
);
1539 knotif
->state
= SECCOMP_NOTIFY_SENT
;
1540 wake_up_poll(&filter
->wqh
, EPOLLOUT
| EPOLLWRNORM
);
1543 mutex_unlock(&filter
->notify_lock
);
1545 if (ret
== 0 && copy_to_user(buf
, &unotif
, sizeof(unotif
))) {
1549 * Userspace screwed up. To make sure that we keep this
1550 * notification alive, let's reset it back to INIT. It
1551 * may have died when we released the lock, so we need to make
1552 * sure it's still around.
1554 mutex_lock(&filter
->notify_lock
);
1555 knotif
= find_notification(filter
, unotif
.id
);
1557 /* Reset the process to make sure it's not stuck */
1558 if (should_sleep_killable(filter
, knotif
))
1559 complete(&knotif
->ready
);
1560 knotif
->state
= SECCOMP_NOTIFY_INIT
;
1561 atomic_inc(&filter
->notif
->requests
);
1562 wake_up_poll(&filter
->wqh
, EPOLLIN
| EPOLLRDNORM
);
1564 mutex_unlock(&filter
->notify_lock
);
1570 static long seccomp_notify_send(struct seccomp_filter
*filter
,
1573 struct seccomp_notif_resp resp
= {};
1574 struct seccomp_knotif
*knotif
;
1577 if (copy_from_user(&resp
, buf
, sizeof(resp
)))
1580 if (resp
.flags
& ~SECCOMP_USER_NOTIF_FLAG_CONTINUE
)
1583 if ((resp
.flags
& SECCOMP_USER_NOTIF_FLAG_CONTINUE
) &&
1584 (resp
.error
|| resp
.val
))
1587 ret
= mutex_lock_interruptible(&filter
->notify_lock
);
1591 knotif
= find_notification(filter
, resp
.id
);
1597 /* Allow exactly one reply. */
1598 if (knotif
->state
!= SECCOMP_NOTIFY_SENT
) {
1604 knotif
->state
= SECCOMP_NOTIFY_REPLIED
;
1605 knotif
->error
= resp
.error
;
1606 knotif
->val
= resp
.val
;
1607 knotif
->flags
= resp
.flags
;
1608 if (filter
->notif
->flags
& SECCOMP_USER_NOTIF_FD_SYNC_WAKE_UP
)
1609 complete_on_current_cpu(&knotif
->ready
);
1611 complete(&knotif
->ready
);
1613 mutex_unlock(&filter
->notify_lock
);
1617 static long seccomp_notify_id_valid(struct seccomp_filter
*filter
,
1620 struct seccomp_knotif
*knotif
;
1624 if (copy_from_user(&id
, buf
, sizeof(id
)))
1627 ret
= mutex_lock_interruptible(&filter
->notify_lock
);
1631 knotif
= find_notification(filter
, id
);
1632 if (knotif
&& knotif
->state
== SECCOMP_NOTIFY_SENT
)
1637 mutex_unlock(&filter
->notify_lock
);
1641 static long seccomp_notify_set_flags(struct seccomp_filter
*filter
,
1642 unsigned long flags
)
1646 if (flags
& ~SECCOMP_USER_NOTIF_FD_SYNC_WAKE_UP
)
1649 ret
= mutex_lock_interruptible(&filter
->notify_lock
);
1652 filter
->notif
->flags
= flags
;
1653 mutex_unlock(&filter
->notify_lock
);
1657 static long seccomp_notify_addfd(struct seccomp_filter
*filter
,
1658 struct seccomp_notif_addfd __user
*uaddfd
,
1661 struct seccomp_notif_addfd addfd
;
1662 struct seccomp_knotif
*knotif
;
1663 struct seccomp_kaddfd kaddfd
;
1666 BUILD_BUG_ON(sizeof(addfd
) < SECCOMP_NOTIFY_ADDFD_SIZE_VER0
);
1667 BUILD_BUG_ON(sizeof(addfd
) != SECCOMP_NOTIFY_ADDFD_SIZE_LATEST
);
1669 if (size
< SECCOMP_NOTIFY_ADDFD_SIZE_VER0
|| size
>= PAGE_SIZE
)
1672 ret
= copy_struct_from_user(&addfd
, sizeof(addfd
), uaddfd
, size
);
1676 if (addfd
.newfd_flags
& ~O_CLOEXEC
)
1679 if (addfd
.flags
& ~(SECCOMP_ADDFD_FLAG_SETFD
| SECCOMP_ADDFD_FLAG_SEND
))
1682 if (addfd
.newfd
&& !(addfd
.flags
& SECCOMP_ADDFD_FLAG_SETFD
))
1685 kaddfd
.file
= fget(addfd
.srcfd
);
1689 kaddfd
.ioctl_flags
= addfd
.flags
;
1690 kaddfd
.flags
= addfd
.newfd_flags
;
1691 kaddfd
.setfd
= addfd
.flags
& SECCOMP_ADDFD_FLAG_SETFD
;
1692 kaddfd
.fd
= addfd
.newfd
;
1693 init_completion(&kaddfd
.completion
);
1695 ret
= mutex_lock_interruptible(&filter
->notify_lock
);
1699 knotif
= find_notification(filter
, addfd
.id
);
1706 * We do not want to allow for FD injection to occur before the
1707 * notification has been picked up by a userspace handler, or after
1708 * the notification has been replied to.
1710 if (knotif
->state
!= SECCOMP_NOTIFY_SENT
) {
1715 if (addfd
.flags
& SECCOMP_ADDFD_FLAG_SEND
) {
1717 * Disallow queuing an atomic addfd + send reply while there are
1718 * some addfd requests still to process.
1720 * There is no clear reason to support it and allows us to keep
1721 * the loop on the other side straight-forward.
1723 if (!list_empty(&knotif
->addfd
)) {
1728 /* Allow exactly only one reply */
1729 knotif
->state
= SECCOMP_NOTIFY_REPLIED
;
1732 list_add(&kaddfd
.list
, &knotif
->addfd
);
1733 complete(&knotif
->ready
);
1734 mutex_unlock(&filter
->notify_lock
);
1736 /* Now we wait for it to be processed or be interrupted */
1737 ret
= wait_for_completion_interruptible(&kaddfd
.completion
);
1740 * We had a successful completion. The other side has already
1741 * removed us from the addfd queue, and
1742 * wait_for_completion_interruptible has a memory barrier upon
1743 * success that lets us read this value directly without
1750 mutex_lock(&filter
->notify_lock
);
1752 * Even though we were woken up by a signal and not a successful
1753 * completion, a completion may have happened in the mean time.
1755 * We need to check again if the addfd request has been handled,
1756 * and if not, we will remove it from the queue.
1758 if (list_empty(&kaddfd
.list
))
1761 list_del(&kaddfd
.list
);
1764 mutex_unlock(&filter
->notify_lock
);
1771 static long seccomp_notify_ioctl(struct file
*file
, unsigned int cmd
,
1774 struct seccomp_filter
*filter
= file
->private_data
;
1775 void __user
*buf
= (void __user
*)arg
;
1777 /* Fixed-size ioctls */
1779 case SECCOMP_IOCTL_NOTIF_RECV
:
1780 return seccomp_notify_recv(filter
, buf
);
1781 case SECCOMP_IOCTL_NOTIF_SEND
:
1782 return seccomp_notify_send(filter
, buf
);
1783 case SECCOMP_IOCTL_NOTIF_ID_VALID_WRONG_DIR
:
1784 case SECCOMP_IOCTL_NOTIF_ID_VALID
:
1785 return seccomp_notify_id_valid(filter
, buf
);
1786 case SECCOMP_IOCTL_NOTIF_SET_FLAGS
:
1787 return seccomp_notify_set_flags(filter
, arg
);
1790 /* Extensible Argument ioctls */
1791 #define EA_IOCTL(cmd) ((cmd) & ~(IOC_INOUT | IOCSIZE_MASK))
1792 switch (EA_IOCTL(cmd
)) {
1793 case EA_IOCTL(SECCOMP_IOCTL_NOTIF_ADDFD
):
1794 return seccomp_notify_addfd(filter
, buf
, _IOC_SIZE(cmd
));
1800 static __poll_t
seccomp_notify_poll(struct file
*file
,
1801 struct poll_table_struct
*poll_tab
)
1803 struct seccomp_filter
*filter
= file
->private_data
;
1805 struct seccomp_knotif
*cur
;
1807 poll_wait(file
, &filter
->wqh
, poll_tab
);
1809 if (mutex_lock_interruptible(&filter
->notify_lock
) < 0)
1812 list_for_each_entry(cur
, &filter
->notif
->notifications
, list
) {
1813 if (cur
->state
== SECCOMP_NOTIFY_INIT
)
1814 ret
|= EPOLLIN
| EPOLLRDNORM
;
1815 if (cur
->state
== SECCOMP_NOTIFY_SENT
)
1816 ret
|= EPOLLOUT
| EPOLLWRNORM
;
1817 if ((ret
& EPOLLIN
) && (ret
& EPOLLOUT
))
1821 mutex_unlock(&filter
->notify_lock
);
1823 if (refcount_read(&filter
->users
) == 0)
1829 static const struct file_operations seccomp_notify_ops
= {
1830 .poll
= seccomp_notify_poll
,
1831 .release
= seccomp_notify_release
,
1832 .unlocked_ioctl
= seccomp_notify_ioctl
,
1833 .compat_ioctl
= seccomp_notify_ioctl
,
1836 static struct file
*init_listener(struct seccomp_filter
*filter
)
1840 ret
= ERR_PTR(-ENOMEM
);
1841 filter
->notif
= kzalloc(sizeof(*(filter
->notif
)), GFP_KERNEL
);
1845 filter
->notif
->next_id
= get_random_u64();
1846 INIT_LIST_HEAD(&filter
->notif
->notifications
);
1848 ret
= anon_inode_getfile("seccomp notify", &seccomp_notify_ops
,
1853 /* The file has a reference to it now */
1854 __get_seccomp_filter(filter
);
1858 seccomp_notify_free(filter
);
1864 * Does @new_child have a listener while an ancestor also has a listener?
1865 * If so, we'll want to reject this filter.
1866 * This only has to be tested for the current process, even in the TSYNC case,
1867 * because TSYNC installs @child with the same parent on all threads.
1868 * Note that @new_child is not hooked up to its parent at this point yet, so
1869 * we use current->seccomp.filter.
1871 static bool has_duplicate_listener(struct seccomp_filter
*new_child
)
1873 struct seccomp_filter
*cur
;
1875 /* must be protected against concurrent TSYNC */
1876 lockdep_assert_held(¤t
->sighand
->siglock
);
1878 if (!new_child
->notif
)
1880 for (cur
= current
->seccomp
.filter
; cur
; cur
= cur
->prev
) {
1889 * seccomp_set_mode_filter: internal function for setting seccomp filter
1890 * @flags: flags to change filter behavior
1891 * @filter: struct sock_fprog containing filter
1893 * This function may be called repeatedly to install additional filters.
1894 * Every filter successfully installed will be evaluated (in reverse order)
1895 * for each system call the task makes.
1897 * Once current->seccomp.mode is non-zero, it may not be changed.
1899 * Returns 0 on success or -EINVAL on failure.
1901 static long seccomp_set_mode_filter(unsigned int flags
,
1902 const char __user
*filter
)
1904 const unsigned long seccomp_mode
= SECCOMP_MODE_FILTER
;
1905 struct seccomp_filter
*prepared
= NULL
;
1908 struct file
*listener_f
= NULL
;
1910 /* Validate flags. */
1911 if (flags
& ~SECCOMP_FILTER_FLAG_MASK
)
1915 * In the successful case, NEW_LISTENER returns the new listener fd.
1916 * But in the failure case, TSYNC returns the thread that died. If you
1917 * combine these two flags, there's no way to tell whether something
1918 * succeeded or failed. So, let's disallow this combination if the user
1919 * has not explicitly requested no errors from TSYNC.
1921 if ((flags
& SECCOMP_FILTER_FLAG_TSYNC
) &&
1922 (flags
& SECCOMP_FILTER_FLAG_NEW_LISTENER
) &&
1923 ((flags
& SECCOMP_FILTER_FLAG_TSYNC_ESRCH
) == 0))
1927 * The SECCOMP_FILTER_FLAG_WAIT_KILLABLE_SENT flag doesn't make sense
1928 * without the SECCOMP_FILTER_FLAG_NEW_LISTENER flag.
1930 if ((flags
& SECCOMP_FILTER_FLAG_WAIT_KILLABLE_RECV
) &&
1931 ((flags
& SECCOMP_FILTER_FLAG_NEW_LISTENER
) == 0))
1934 /* Prepare the new filter before holding any locks. */
1935 prepared
= seccomp_prepare_user_filter(filter
);
1936 if (IS_ERR(prepared
))
1937 return PTR_ERR(prepared
);
1939 if (flags
& SECCOMP_FILTER_FLAG_NEW_LISTENER
) {
1940 listener
= get_unused_fd_flags(O_CLOEXEC
);
1946 listener_f
= init_listener(prepared
);
1947 if (IS_ERR(listener_f
)) {
1948 put_unused_fd(listener
);
1949 ret
= PTR_ERR(listener_f
);
1955 * Make sure we cannot change seccomp or nnp state via TSYNC
1956 * while another thread is in the middle of calling exec.
1958 if (flags
& SECCOMP_FILTER_FLAG_TSYNC
&&
1959 mutex_lock_killable(¤t
->signal
->cred_guard_mutex
))
1962 spin_lock_irq(¤t
->sighand
->siglock
);
1964 if (!seccomp_may_assign_mode(seccomp_mode
))
1967 if (has_duplicate_listener(prepared
)) {
1972 ret
= seccomp_attach_filter(flags
, prepared
);
1975 /* Do not free the successfully attached filter. */
1978 seccomp_assign_mode(current
, seccomp_mode
, flags
);
1980 spin_unlock_irq(¤t
->sighand
->siglock
);
1981 if (flags
& SECCOMP_FILTER_FLAG_TSYNC
)
1982 mutex_unlock(¤t
->signal
->cred_guard_mutex
);
1984 if (flags
& SECCOMP_FILTER_FLAG_NEW_LISTENER
) {
1986 listener_f
->private_data
= NULL
;
1988 put_unused_fd(listener
);
1989 seccomp_notify_detach(prepared
);
1991 fd_install(listener
, listener_f
);
1996 seccomp_filter_free(prepared
);
2000 static inline long seccomp_set_mode_filter(unsigned int flags
,
2001 const char __user
*filter
)
2007 static long seccomp_get_action_avail(const char __user
*uaction
)
2011 if (copy_from_user(&action
, uaction
, sizeof(action
)))
2015 case SECCOMP_RET_KILL_PROCESS
:
2016 case SECCOMP_RET_KILL_THREAD
:
2017 case SECCOMP_RET_TRAP
:
2018 case SECCOMP_RET_ERRNO
:
2019 case SECCOMP_RET_USER_NOTIF
:
2020 case SECCOMP_RET_TRACE
:
2021 case SECCOMP_RET_LOG
:
2022 case SECCOMP_RET_ALLOW
:
2031 static long seccomp_get_notif_sizes(void __user
*usizes
)
2033 struct seccomp_notif_sizes sizes
= {
2034 .seccomp_notif
= sizeof(struct seccomp_notif
),
2035 .seccomp_notif_resp
= sizeof(struct seccomp_notif_resp
),
2036 .seccomp_data
= sizeof(struct seccomp_data
),
2039 if (copy_to_user(usizes
, &sizes
, sizeof(sizes
)))
2045 /* Common entry point for both prctl and syscall. */
2046 static long do_seccomp(unsigned int op
, unsigned int flags
,
2050 case SECCOMP_SET_MODE_STRICT
:
2051 if (flags
!= 0 || uargs
!= NULL
)
2053 return seccomp_set_mode_strict();
2054 case SECCOMP_SET_MODE_FILTER
:
2055 return seccomp_set_mode_filter(flags
, uargs
);
2056 case SECCOMP_GET_ACTION_AVAIL
:
2060 return seccomp_get_action_avail(uargs
);
2061 case SECCOMP_GET_NOTIF_SIZES
:
2065 return seccomp_get_notif_sizes(uargs
);
2071 SYSCALL_DEFINE3(seccomp
, unsigned int, op
, unsigned int, flags
,
2072 void __user
*, uargs
)
2074 return do_seccomp(op
, flags
, uargs
);
2078 * prctl_set_seccomp: configures current->seccomp.mode
2079 * @seccomp_mode: requested mode to use
2080 * @filter: optional struct sock_fprog for use with SECCOMP_MODE_FILTER
2082 * Returns 0 on success or -EINVAL on failure.
2084 long prctl_set_seccomp(unsigned long seccomp_mode
, void __user
*filter
)
2089 switch (seccomp_mode
) {
2090 case SECCOMP_MODE_STRICT
:
2091 op
= SECCOMP_SET_MODE_STRICT
;
2093 * Setting strict mode through prctl always ignored filter,
2094 * so make sure it is always NULL here to pass the internal
2095 * check in do_seccomp().
2099 case SECCOMP_MODE_FILTER
:
2100 op
= SECCOMP_SET_MODE_FILTER
;
2107 /* prctl interface doesn't have flags, so they are always zero. */
2108 return do_seccomp(op
, 0, uargs
);
2111 #if defined(CONFIG_SECCOMP_FILTER) && defined(CONFIG_CHECKPOINT_RESTORE)
2112 static struct seccomp_filter
*get_nth_filter(struct task_struct
*task
,
2113 unsigned long filter_off
)
2115 struct seccomp_filter
*orig
, *filter
;
2116 unsigned long count
;
2119 * Note: this is only correct because the caller should be the (ptrace)
2120 * tracer of the task, otherwise lock_task_sighand is needed.
2122 spin_lock_irq(&task
->sighand
->siglock
);
2124 if (task
->seccomp
.mode
!= SECCOMP_MODE_FILTER
) {
2125 spin_unlock_irq(&task
->sighand
->siglock
);
2126 return ERR_PTR(-EINVAL
);
2129 orig
= task
->seccomp
.filter
;
2130 __get_seccomp_filter(orig
);
2131 spin_unlock_irq(&task
->sighand
->siglock
);
2134 for (filter
= orig
; filter
; filter
= filter
->prev
)
2137 if (filter_off
>= count
) {
2138 filter
= ERR_PTR(-ENOENT
);
2142 count
-= filter_off
;
2143 for (filter
= orig
; filter
&& count
> 1; filter
= filter
->prev
)
2146 if (WARN_ON(count
!= 1 || !filter
)) {
2147 filter
= ERR_PTR(-ENOENT
);
2151 __get_seccomp_filter(filter
);
2154 __put_seccomp_filter(orig
);
2158 long seccomp_get_filter(struct task_struct
*task
, unsigned long filter_off
,
2161 struct seccomp_filter
*filter
;
2162 struct sock_fprog_kern
*fprog
;
2165 if (!capable(CAP_SYS_ADMIN
) ||
2166 current
->seccomp
.mode
!= SECCOMP_MODE_DISABLED
) {
2170 filter
= get_nth_filter(task
, filter_off
);
2172 return PTR_ERR(filter
);
2174 fprog
= filter
->prog
->orig_prog
;
2176 /* This must be a new non-cBPF filter, since we save
2177 * every cBPF filter's orig_prog above when
2178 * CONFIG_CHECKPOINT_RESTORE is enabled.
2188 if (copy_to_user(data
, fprog
->filter
, bpf_classic_proglen(fprog
)))
2192 __put_seccomp_filter(filter
);
2196 long seccomp_get_metadata(struct task_struct
*task
,
2197 unsigned long size
, void __user
*data
)
2200 struct seccomp_filter
*filter
;
2201 struct seccomp_metadata kmd
= {};
2203 if (!capable(CAP_SYS_ADMIN
) ||
2204 current
->seccomp
.mode
!= SECCOMP_MODE_DISABLED
) {
2208 size
= min_t(unsigned long, size
, sizeof(kmd
));
2210 if (size
< sizeof(kmd
.filter_off
))
2213 if (copy_from_user(&kmd
.filter_off
, data
, sizeof(kmd
.filter_off
)))
2216 filter
= get_nth_filter(task
, kmd
.filter_off
);
2218 return PTR_ERR(filter
);
2221 kmd
.flags
|= SECCOMP_FILTER_FLAG_LOG
;
2224 if (copy_to_user(data
, &kmd
, size
))
2227 __put_seccomp_filter(filter
);
2232 #ifdef CONFIG_SYSCTL
2234 /* Human readable action names for friendly sysctl interaction */
2235 #define SECCOMP_RET_KILL_PROCESS_NAME "kill_process"
2236 #define SECCOMP_RET_KILL_THREAD_NAME "kill_thread"
2237 #define SECCOMP_RET_TRAP_NAME "trap"
2238 #define SECCOMP_RET_ERRNO_NAME "errno"
2239 #define SECCOMP_RET_USER_NOTIF_NAME "user_notif"
2240 #define SECCOMP_RET_TRACE_NAME "trace"
2241 #define SECCOMP_RET_LOG_NAME "log"
2242 #define SECCOMP_RET_ALLOW_NAME "allow"
2244 static const char seccomp_actions_avail
[] =
2245 SECCOMP_RET_KILL_PROCESS_NAME
" "
2246 SECCOMP_RET_KILL_THREAD_NAME
" "
2247 SECCOMP_RET_TRAP_NAME
" "
2248 SECCOMP_RET_ERRNO_NAME
" "
2249 SECCOMP_RET_USER_NOTIF_NAME
" "
2250 SECCOMP_RET_TRACE_NAME
" "
2251 SECCOMP_RET_LOG_NAME
" "
2252 SECCOMP_RET_ALLOW_NAME
;
2254 struct seccomp_log_name
{
2259 static const struct seccomp_log_name seccomp_log_names
[] = {
2260 { SECCOMP_LOG_KILL_PROCESS
, SECCOMP_RET_KILL_PROCESS_NAME
},
2261 { SECCOMP_LOG_KILL_THREAD
, SECCOMP_RET_KILL_THREAD_NAME
},
2262 { SECCOMP_LOG_TRAP
, SECCOMP_RET_TRAP_NAME
},
2263 { SECCOMP_LOG_ERRNO
, SECCOMP_RET_ERRNO_NAME
},
2264 { SECCOMP_LOG_USER_NOTIF
, SECCOMP_RET_USER_NOTIF_NAME
},
2265 { SECCOMP_LOG_TRACE
, SECCOMP_RET_TRACE_NAME
},
2266 { SECCOMP_LOG_LOG
, SECCOMP_RET_LOG_NAME
},
2267 { SECCOMP_LOG_ALLOW
, SECCOMP_RET_ALLOW_NAME
},
2271 static bool seccomp_names_from_actions_logged(char *names
, size_t size
,
2275 const struct seccomp_log_name
*cur
;
2276 bool append_sep
= false;
2278 for (cur
= seccomp_log_names
; cur
->name
&& size
; cur
++) {
2281 if (!(actions_logged
& cur
->log
))
2285 ret
= strscpy(names
, sep
, size
);
2294 ret
= strscpy(names
, cur
->name
, size
);
2305 static bool seccomp_action_logged_from_name(u32
*action_logged
,
2308 const struct seccomp_log_name
*cur
;
2310 for (cur
= seccomp_log_names
; cur
->name
; cur
++) {
2311 if (!strcmp(cur
->name
, name
)) {
2312 *action_logged
= cur
->log
;
2320 static bool seccomp_actions_logged_from_names(u32
*actions_logged
, char *names
)
2324 *actions_logged
= 0;
2325 while ((name
= strsep(&names
, " ")) && *name
) {
2326 u32 action_logged
= 0;
2328 if (!seccomp_action_logged_from_name(&action_logged
, name
))
2331 *actions_logged
|= action_logged
;
2337 static int read_actions_logged(struct ctl_table
*ro_table
, void *buffer
,
2338 size_t *lenp
, loff_t
*ppos
)
2340 char names
[sizeof(seccomp_actions_avail
)];
2341 struct ctl_table table
;
2343 memset(names
, 0, sizeof(names
));
2345 if (!seccomp_names_from_actions_logged(names
, sizeof(names
),
2346 seccomp_actions_logged
, " "))
2351 table
.maxlen
= sizeof(names
);
2352 return proc_dostring(&table
, 0, buffer
, lenp
, ppos
);
2355 static int write_actions_logged(struct ctl_table
*ro_table
, void *buffer
,
2356 size_t *lenp
, loff_t
*ppos
, u32
*actions_logged
)
2358 char names
[sizeof(seccomp_actions_avail
)];
2359 struct ctl_table table
;
2362 if (!capable(CAP_SYS_ADMIN
))
2365 memset(names
, 0, sizeof(names
));
2369 table
.maxlen
= sizeof(names
);
2370 ret
= proc_dostring(&table
, 1, buffer
, lenp
, ppos
);
2374 if (!seccomp_actions_logged_from_names(actions_logged
, table
.data
))
2377 if (*actions_logged
& SECCOMP_LOG_ALLOW
)
2380 seccomp_actions_logged
= *actions_logged
;
2384 static void audit_actions_logged(u32 actions_logged
, u32 old_actions_logged
,
2387 char names
[sizeof(seccomp_actions_avail
)];
2388 char old_names
[sizeof(seccomp_actions_avail
)];
2389 const char *new = names
;
2390 const char *old
= old_names
;
2395 memset(names
, 0, sizeof(names
));
2396 memset(old_names
, 0, sizeof(old_names
));
2400 else if (!actions_logged
)
2402 else if (!seccomp_names_from_actions_logged(names
, sizeof(names
),
2403 actions_logged
, ","))
2406 if (!old_actions_logged
)
2408 else if (!seccomp_names_from_actions_logged(old_names
,
2410 old_actions_logged
, ","))
2413 return audit_seccomp_actions_logged(new, old
, !ret
);
2416 static int seccomp_actions_logged_handler(struct ctl_table
*ro_table
, int write
,
2417 void *buffer
, size_t *lenp
,
2423 u32 actions_logged
= 0;
2424 u32 old_actions_logged
= seccomp_actions_logged
;
2426 ret
= write_actions_logged(ro_table
, buffer
, lenp
, ppos
,
2428 audit_actions_logged(actions_logged
, old_actions_logged
, ret
);
2430 ret
= read_actions_logged(ro_table
, buffer
, lenp
, ppos
);
2435 static struct ctl_table seccomp_sysctl_table
[] = {
2437 .procname
= "actions_avail",
2438 .data
= (void *) &seccomp_actions_avail
,
2439 .maxlen
= sizeof(seccomp_actions_avail
),
2441 .proc_handler
= proc_dostring
,
2444 .procname
= "actions_logged",
2446 .proc_handler
= seccomp_actions_logged_handler
,
2451 static int __init
seccomp_sysctl_init(void)
2453 register_sysctl_init("kernel/seccomp", seccomp_sysctl_table
);
2457 device_initcall(seccomp_sysctl_init
)
2459 #endif /* CONFIG_SYSCTL */
2461 #ifdef CONFIG_SECCOMP_CACHE_DEBUG
2462 /* Currently CONFIG_SECCOMP_CACHE_DEBUG implies SECCOMP_ARCH_NATIVE */
2463 static void proc_pid_seccomp_cache_arch(struct seq_file
*m
, const char *name
,
2464 const void *bitmap
, size_t bitmap_size
)
2468 for (nr
= 0; nr
< bitmap_size
; nr
++) {
2469 bool cached
= test_bit(nr
, bitmap
);
2470 char *status
= cached
? "ALLOW" : "FILTER";
2472 seq_printf(m
, "%s %d %s\n", name
, nr
, status
);
2476 int proc_pid_seccomp_cache(struct seq_file
*m
, struct pid_namespace
*ns
,
2477 struct pid
*pid
, struct task_struct
*task
)
2479 struct seccomp_filter
*f
;
2480 unsigned long flags
;
2483 * We don't want some sandboxed process to know what their seccomp
2484 * filters consist of.
2486 if (!file_ns_capable(m
->file
, &init_user_ns
, CAP_SYS_ADMIN
))
2489 if (!lock_task_sighand(task
, &flags
))
2492 f
= READ_ONCE(task
->seccomp
.filter
);
2494 unlock_task_sighand(task
, &flags
);
2498 /* prevent filter from being freed while we are printing it */
2499 __get_seccomp_filter(f
);
2500 unlock_task_sighand(task
, &flags
);
2502 proc_pid_seccomp_cache_arch(m
, SECCOMP_ARCH_NATIVE_NAME
,
2503 f
->cache
.allow_native
,
2504 SECCOMP_ARCH_NATIVE_NR
);
2506 #ifdef SECCOMP_ARCH_COMPAT
2507 proc_pid_seccomp_cache_arch(m
, SECCOMP_ARCH_COMPAT_NAME
,
2508 f
->cache
.allow_compat
,
2509 SECCOMP_ARCH_COMPAT_NR
);
2510 #endif /* SECCOMP_ARCH_COMPAT */
2512 __put_seccomp_filter(f
);
2515 #endif /* CONFIG_SECCOMP_CACHE_DEBUG */