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
)
505 /* Skip exited threads. */
506 if (thread
->flags
& PF_EXITING
)
509 if (thread
->seccomp
.mode
== SECCOMP_MODE_DISABLED
||
510 (thread
->seccomp
.mode
== SECCOMP_MODE_FILTER
&&
511 is_ancestor(thread
->seccomp
.filter
,
512 caller
->seccomp
.filter
)))
515 /* Return the first thread that cannot be synchronized. */
516 failed
= task_pid_vnr(thread
);
517 /* If the pid cannot be resolved, then return -ESRCH */
518 if (WARN_ON(failed
== 0))
526 static inline void seccomp_filter_free(struct seccomp_filter
*filter
)
529 bpf_prog_destroy(filter
->prog
);
534 static void __seccomp_filter_orphan(struct seccomp_filter
*orig
)
536 while (orig
&& refcount_dec_and_test(&orig
->users
)) {
537 if (waitqueue_active(&orig
->wqh
))
538 wake_up_poll(&orig
->wqh
, EPOLLHUP
);
543 static void __put_seccomp_filter(struct seccomp_filter
*orig
)
545 /* Clean up single-reference branches iteratively. */
546 while (orig
&& refcount_dec_and_test(&orig
->refs
)) {
547 struct seccomp_filter
*freeme
= orig
;
549 seccomp_filter_free(freeme
);
553 static void __seccomp_filter_release(struct seccomp_filter
*orig
)
555 /* Notify about any unused filters in the task's former filter tree. */
556 __seccomp_filter_orphan(orig
);
557 /* Finally drop all references to the task's former tree. */
558 __put_seccomp_filter(orig
);
562 * seccomp_filter_release - Detach the task from its filter tree,
563 * drop its reference count, and notify
564 * about unused filters
566 * @tsk: task the filter should be released from.
568 * This function should only be called when the task is exiting as
569 * it detaches it from its filter tree. PF_EXITING has to be set
572 void seccomp_filter_release(struct task_struct
*tsk
)
574 struct seccomp_filter
*orig
;
576 if (WARN_ON((tsk
->flags
& PF_EXITING
) == 0))
579 spin_lock_irq(&tsk
->sighand
->siglock
);
580 orig
= tsk
->seccomp
.filter
;
581 /* Detach task from its filter tree. */
582 tsk
->seccomp
.filter
= NULL
;
583 spin_unlock_irq(&tsk
->sighand
->siglock
);
584 __seccomp_filter_release(orig
);
588 * seccomp_sync_threads: sets all threads to use current's filter
590 * @flags: SECCOMP_FILTER_FLAG_* flags to set during sync.
592 * Expects sighand and cred_guard_mutex locks to be held, and for
593 * seccomp_can_sync_threads() to have returned success already
594 * without dropping the locks.
597 static inline void seccomp_sync_threads(unsigned long flags
)
599 struct task_struct
*thread
, *caller
;
601 BUG_ON(!mutex_is_locked(¤t
->signal
->cred_guard_mutex
));
602 assert_spin_locked(¤t
->sighand
->siglock
);
604 /* Synchronize all threads. */
606 for_each_thread(caller
, thread
) {
607 /* Skip current, since it needs no changes. */
608 if (thread
== caller
)
612 * Skip exited threads. seccomp_filter_release could have
613 * been already called for this task.
615 if (thread
->flags
& PF_EXITING
)
618 /* Get a task reference for the new leaf node. */
619 get_seccomp_filter(caller
);
622 * Drop the task reference to the shared ancestor since
623 * current's path will hold a reference. (This also
624 * allows a put before the assignment.)
626 __seccomp_filter_release(thread
->seccomp
.filter
);
628 /* Make our new filter tree visible. */
629 smp_store_release(&thread
->seccomp
.filter
,
630 caller
->seccomp
.filter
);
631 atomic_set(&thread
->seccomp
.filter_count
,
632 atomic_read(&caller
->seccomp
.filter_count
));
635 * Don't let an unprivileged task work around
636 * the no_new_privs restriction by creating
637 * a thread that sets it up, enters seccomp,
640 if (task_no_new_privs(caller
))
641 task_set_no_new_privs(thread
);
644 * Opt the other thread into seccomp if needed.
645 * As threads are considered to be trust-realm
646 * equivalent (see ptrace_may_access), it is safe to
647 * allow one thread to transition the other.
649 if (thread
->seccomp
.mode
== SECCOMP_MODE_DISABLED
)
650 seccomp_assign_mode(thread
, SECCOMP_MODE_FILTER
,
656 * seccomp_prepare_filter: Prepares a seccomp filter for use.
657 * @fprog: BPF program to install
659 * Returns filter on success or an ERR_PTR on failure.
661 static struct seccomp_filter
*seccomp_prepare_filter(struct sock_fprog
*fprog
)
663 struct seccomp_filter
*sfilter
;
665 const bool save_orig
=
666 #if defined(CONFIG_CHECKPOINT_RESTORE) || defined(SECCOMP_ARCH_NATIVE)
672 if (fprog
->len
== 0 || fprog
->len
> BPF_MAXINSNS
)
673 return ERR_PTR(-EINVAL
);
675 BUG_ON(INT_MAX
/ fprog
->len
< sizeof(struct sock_filter
));
678 * Installing a seccomp filter requires that the task has
679 * CAP_SYS_ADMIN in its namespace or be running with no_new_privs.
680 * This avoids scenarios where unprivileged tasks can affect the
681 * behavior of privileged children.
683 if (!task_no_new_privs(current
) &&
684 !ns_capable_noaudit(current_user_ns(), CAP_SYS_ADMIN
))
685 return ERR_PTR(-EACCES
);
687 /* Allocate a new seccomp_filter */
688 sfilter
= kzalloc(sizeof(*sfilter
), GFP_KERNEL
| __GFP_NOWARN
);
690 return ERR_PTR(-ENOMEM
);
692 mutex_init(&sfilter
->notify_lock
);
693 ret
= bpf_prog_create_from_user(&sfilter
->prog
, fprog
,
694 seccomp_check_filter
, save_orig
);
700 refcount_set(&sfilter
->refs
, 1);
701 refcount_set(&sfilter
->users
, 1);
702 init_waitqueue_head(&sfilter
->wqh
);
708 * seccomp_prepare_user_filter - prepares a user-supplied sock_fprog
709 * @user_filter: pointer to the user data containing a sock_fprog.
711 * Returns 0 on success and non-zero otherwise.
713 static struct seccomp_filter
*
714 seccomp_prepare_user_filter(const char __user
*user_filter
)
716 struct sock_fprog fprog
;
717 struct seccomp_filter
*filter
= ERR_PTR(-EFAULT
);
720 if (in_compat_syscall()) {
721 struct compat_sock_fprog fprog32
;
722 if (copy_from_user(&fprog32
, user_filter
, sizeof(fprog32
)))
724 fprog
.len
= fprog32
.len
;
725 fprog
.filter
= compat_ptr(fprog32
.filter
);
726 } else /* falls through to the if below. */
728 if (copy_from_user(&fprog
, user_filter
, sizeof(fprog
)))
730 filter
= seccomp_prepare_filter(&fprog
);
735 #ifdef SECCOMP_ARCH_NATIVE
737 * seccomp_is_const_allow - check if filter is constant allow with given data
738 * @fprog: The BPF programs
739 * @sd: The seccomp data to check against, only syscall number and arch
740 * number are considered constant.
742 static bool seccomp_is_const_allow(struct sock_fprog_kern
*fprog
,
743 struct seccomp_data
*sd
)
745 unsigned int reg_value
= 0;
749 if (WARN_ON_ONCE(!fprog
))
752 for (pc
= 0; pc
< fprog
->len
; pc
++) {
753 struct sock_filter
*insn
= &fprog
->filter
[pc
];
754 u16 code
= insn
->code
;
758 case BPF_LD
| BPF_W
| BPF_ABS
:
760 case offsetof(struct seccomp_data
, nr
):
763 case offsetof(struct seccomp_data
, arch
):
764 reg_value
= sd
->arch
;
767 /* can't optimize (non-constant value load) */
771 case BPF_RET
| BPF_K
:
772 /* reached return with constant values only, check allow */
773 return k
== SECCOMP_RET_ALLOW
;
774 case BPF_JMP
| BPF_JA
:
777 case BPF_JMP
| BPF_JEQ
| BPF_K
:
778 case BPF_JMP
| BPF_JGE
| BPF_K
:
779 case BPF_JMP
| BPF_JGT
| BPF_K
:
780 case BPF_JMP
| BPF_JSET
| BPF_K
:
781 switch (BPF_OP(code
)) {
783 op_res
= reg_value
== k
;
786 op_res
= reg_value
>= k
;
789 op_res
= reg_value
> k
;
792 op_res
= !!(reg_value
& k
);
795 /* can't optimize (unknown jump) */
799 pc
+= op_res
? insn
->jt
: insn
->jf
;
801 case BPF_ALU
| BPF_AND
| BPF_K
:
805 /* can't optimize (unknown insn) */
810 /* ran off the end of the filter?! */
815 static void seccomp_cache_prepare_bitmap(struct seccomp_filter
*sfilter
,
816 void *bitmap
, const void *bitmap_prev
,
817 size_t bitmap_size
, int arch
)
819 struct sock_fprog_kern
*fprog
= sfilter
->prog
->orig_prog
;
820 struct seccomp_data sd
;
824 /* The new filter must be as restrictive as the last. */
825 bitmap_copy(bitmap
, bitmap_prev
, bitmap_size
);
827 /* Before any filters, all syscalls are always allowed. */
828 bitmap_fill(bitmap
, bitmap_size
);
831 for (nr
= 0; nr
< bitmap_size
; nr
++) {
832 /* No bitmap change: not a cacheable action. */
833 if (!test_bit(nr
, bitmap
))
839 /* No bitmap change: continue to always allow. */
840 if (seccomp_is_const_allow(fprog
, &sd
))
844 * Not a cacheable action: always run filters.
845 * atomic clear_bit() not needed, filter not visible yet.
847 __clear_bit(nr
, bitmap
);
852 * seccomp_cache_prepare - emulate the filter to find cacheable syscalls
853 * @sfilter: The seccomp filter
855 * Returns 0 if successful or -errno if error occurred.
857 static void seccomp_cache_prepare(struct seccomp_filter
*sfilter
)
859 struct action_cache
*cache
= &sfilter
->cache
;
860 const struct action_cache
*cache_prev
=
861 sfilter
->prev
? &sfilter
->prev
->cache
: NULL
;
863 seccomp_cache_prepare_bitmap(sfilter
, cache
->allow_native
,
864 cache_prev
? cache_prev
->allow_native
: NULL
,
865 SECCOMP_ARCH_NATIVE_NR
,
866 SECCOMP_ARCH_NATIVE
);
868 #ifdef SECCOMP_ARCH_COMPAT
869 seccomp_cache_prepare_bitmap(sfilter
, cache
->allow_compat
,
870 cache_prev
? cache_prev
->allow_compat
: NULL
,
871 SECCOMP_ARCH_COMPAT_NR
,
872 SECCOMP_ARCH_COMPAT
);
873 #endif /* SECCOMP_ARCH_COMPAT */
875 #endif /* SECCOMP_ARCH_NATIVE */
878 * seccomp_attach_filter: validate and attach filter
879 * @flags: flags to change filter behavior
880 * @filter: seccomp filter to add to the current process
882 * Caller must be holding current->sighand->siglock lock.
884 * Returns 0 on success, -ve on error, or
885 * - in TSYNC mode: the pid of a thread which was either not in the correct
886 * seccomp mode or did not have an ancestral seccomp filter
887 * - in NEW_LISTENER mode: the fd of the new listener
889 static long seccomp_attach_filter(unsigned int flags
,
890 struct seccomp_filter
*filter
)
892 unsigned long total_insns
;
893 struct seccomp_filter
*walker
;
895 assert_spin_locked(¤t
->sighand
->siglock
);
897 /* Validate resulting filter length. */
898 total_insns
= filter
->prog
->len
;
899 for (walker
= current
->seccomp
.filter
; walker
; walker
= walker
->prev
)
900 total_insns
+= walker
->prog
->len
+ 4; /* 4 instr penalty */
901 if (total_insns
> MAX_INSNS_PER_PATH
)
904 /* If thread sync has been requested, check that it is possible. */
905 if (flags
& SECCOMP_FILTER_FLAG_TSYNC
) {
908 ret
= seccomp_can_sync_threads();
910 if (flags
& SECCOMP_FILTER_FLAG_TSYNC_ESRCH
)
917 /* Set log flag, if present. */
918 if (flags
& SECCOMP_FILTER_FLAG_LOG
)
921 /* Set wait killable flag, if present. */
922 if (flags
& SECCOMP_FILTER_FLAG_WAIT_KILLABLE_RECV
)
923 filter
->wait_killable_recv
= true;
926 * If there is an existing filter, make it the prev and don't drop its
929 filter
->prev
= current
->seccomp
.filter
;
930 seccomp_cache_prepare(filter
);
931 current
->seccomp
.filter
= filter
;
932 atomic_inc(¤t
->seccomp
.filter_count
);
934 /* Now that the new filter is in place, synchronize to all threads. */
935 if (flags
& SECCOMP_FILTER_FLAG_TSYNC
)
936 seccomp_sync_threads(flags
);
941 static void __get_seccomp_filter(struct seccomp_filter
*filter
)
943 refcount_inc(&filter
->refs
);
946 /* get_seccomp_filter - increments the reference count of the filter on @tsk */
947 void get_seccomp_filter(struct task_struct
*tsk
)
949 struct seccomp_filter
*orig
= tsk
->seccomp
.filter
;
952 __get_seccomp_filter(orig
);
953 refcount_inc(&orig
->users
);
956 #endif /* CONFIG_SECCOMP_FILTER */
958 /* For use with seccomp_actions_logged */
959 #define SECCOMP_LOG_KILL_PROCESS (1 << 0)
960 #define SECCOMP_LOG_KILL_THREAD (1 << 1)
961 #define SECCOMP_LOG_TRAP (1 << 2)
962 #define SECCOMP_LOG_ERRNO (1 << 3)
963 #define SECCOMP_LOG_TRACE (1 << 4)
964 #define SECCOMP_LOG_LOG (1 << 5)
965 #define SECCOMP_LOG_ALLOW (1 << 6)
966 #define SECCOMP_LOG_USER_NOTIF (1 << 7)
968 static u32 seccomp_actions_logged
= SECCOMP_LOG_KILL_PROCESS
|
969 SECCOMP_LOG_KILL_THREAD
|
972 SECCOMP_LOG_USER_NOTIF
|
976 static inline void seccomp_log(unsigned long syscall
, long signr
, u32 action
,
982 case SECCOMP_RET_ALLOW
:
984 case SECCOMP_RET_TRAP
:
985 log
= requested
&& seccomp_actions_logged
& SECCOMP_LOG_TRAP
;
987 case SECCOMP_RET_ERRNO
:
988 log
= requested
&& seccomp_actions_logged
& SECCOMP_LOG_ERRNO
;
990 case SECCOMP_RET_TRACE
:
991 log
= requested
&& seccomp_actions_logged
& SECCOMP_LOG_TRACE
;
993 case SECCOMP_RET_USER_NOTIF
:
994 log
= requested
&& seccomp_actions_logged
& SECCOMP_LOG_USER_NOTIF
;
996 case SECCOMP_RET_LOG
:
997 log
= seccomp_actions_logged
& SECCOMP_LOG_LOG
;
999 case SECCOMP_RET_KILL_THREAD
:
1000 log
= seccomp_actions_logged
& SECCOMP_LOG_KILL_THREAD
;
1002 case SECCOMP_RET_KILL_PROCESS
:
1004 log
= seccomp_actions_logged
& SECCOMP_LOG_KILL_PROCESS
;
1008 * Emit an audit message when the action is RET_KILL_*, RET_LOG, or the
1009 * FILTER_FLAG_LOG bit was set. The admin has the ability to silence
1010 * any action from being logged by removing the action name from the
1011 * seccomp_actions_logged sysctl.
1016 audit_seccomp(syscall
, signr
, action
);
1020 * Secure computing mode 1 allows only read/write/exit/sigreturn.
1021 * To be fully secure this must be combined with rlimit
1022 * to limit the stack allocations too.
1024 static const int mode1_syscalls
[] = {
1025 __NR_seccomp_read
, __NR_seccomp_write
, __NR_seccomp_exit
, __NR_seccomp_sigreturn
,
1026 -1, /* negative terminated */
1029 static void __secure_computing_strict(int this_syscall
)
1031 const int *allowed_syscalls
= mode1_syscalls
;
1032 #ifdef CONFIG_COMPAT
1033 if (in_compat_syscall())
1034 allowed_syscalls
= get_compat_mode1_syscalls();
1037 if (*allowed_syscalls
== this_syscall
)
1039 } while (*++allowed_syscalls
!= -1);
1041 #ifdef SECCOMP_DEBUG
1044 current
->seccomp
.mode
= SECCOMP_MODE_DEAD
;
1045 seccomp_log(this_syscall
, SIGKILL
, SECCOMP_RET_KILL_THREAD
, true);
1049 #ifndef CONFIG_HAVE_ARCH_SECCOMP_FILTER
1050 void secure_computing_strict(int this_syscall
)
1052 int mode
= current
->seccomp
.mode
;
1054 if (IS_ENABLED(CONFIG_CHECKPOINT_RESTORE
) &&
1055 unlikely(current
->ptrace
& PT_SUSPEND_SECCOMP
))
1058 if (mode
== SECCOMP_MODE_DISABLED
)
1060 else if (mode
== SECCOMP_MODE_STRICT
)
1061 __secure_computing_strict(this_syscall
);
1067 #ifdef CONFIG_SECCOMP_FILTER
1068 static u64
seccomp_next_notify_id(struct seccomp_filter
*filter
)
1071 * Note: overflow is ok here, the id just needs to be unique per
1074 lockdep_assert_held(&filter
->notify_lock
);
1075 return filter
->notif
->next_id
++;
1078 static void seccomp_handle_addfd(struct seccomp_kaddfd
*addfd
, struct seccomp_knotif
*n
)
1083 * Remove the notification, and reset the list pointers, indicating
1084 * that it has been handled.
1086 list_del_init(&addfd
->list
);
1088 fd
= receive_fd(addfd
->file
, NULL
, addfd
->flags
);
1090 fd
= receive_fd_replace(addfd
->fd
, addfd
->file
, addfd
->flags
);
1093 if (addfd
->ioctl_flags
& SECCOMP_ADDFD_FLAG_SEND
) {
1094 /* If we fail reset and return an error to the notifier */
1096 n
->state
= SECCOMP_NOTIFY_SENT
;
1098 /* Return the FD we just added */
1106 * Mark the notification as completed. From this point, addfd mem
1107 * might be invalidated and we can't safely read it anymore.
1109 complete(&addfd
->completion
);
1112 static bool should_sleep_killable(struct seccomp_filter
*match
,
1113 struct seccomp_knotif
*n
)
1115 return match
->wait_killable_recv
&& n
->state
== SECCOMP_NOTIFY_SENT
;
1118 static int seccomp_do_user_notification(int this_syscall
,
1119 struct seccomp_filter
*match
,
1120 const struct seccomp_data
*sd
)
1125 struct seccomp_knotif n
= {};
1126 struct seccomp_kaddfd
*addfd
, *tmp
;
1128 mutex_lock(&match
->notify_lock
);
1134 n
.state
= SECCOMP_NOTIFY_INIT
;
1136 n
.id
= seccomp_next_notify_id(match
);
1137 init_completion(&n
.ready
);
1138 list_add_tail(&n
.list
, &match
->notif
->notifications
);
1139 INIT_LIST_HEAD(&n
.addfd
);
1141 atomic_inc(&match
->notif
->requests
);
1142 if (match
->notif
->flags
& SECCOMP_USER_NOTIF_FD_SYNC_WAKE_UP
)
1143 wake_up_poll_on_current_cpu(&match
->wqh
, EPOLLIN
| EPOLLRDNORM
);
1145 wake_up_poll(&match
->wqh
, EPOLLIN
| EPOLLRDNORM
);
1148 * This is where we wait for a reply from userspace.
1151 bool wait_killable
= should_sleep_killable(match
, &n
);
1153 mutex_unlock(&match
->notify_lock
);
1155 err
= wait_for_completion_killable(&n
.ready
);
1157 err
= wait_for_completion_interruptible(&n
.ready
);
1158 mutex_lock(&match
->notify_lock
);
1162 * Check to see if the notifcation got picked up and
1163 * whether we should switch to wait killable.
1165 if (!wait_killable
&& should_sleep_killable(match
, &n
))
1171 addfd
= list_first_entry_or_null(&n
.addfd
,
1172 struct seccomp_kaddfd
, list
);
1173 /* Check if we were woken up by a addfd message */
1175 seccomp_handle_addfd(addfd
, &n
);
1177 } while (n
.state
!= SECCOMP_NOTIFY_REPLIED
);
1184 /* If there were any pending addfd calls, clear them out */
1185 list_for_each_entry_safe(addfd
, tmp
, &n
.addfd
, list
) {
1186 /* The process went away before we got a chance to handle it */
1187 addfd
->ret
= -ESRCH
;
1188 list_del_init(&addfd
->list
);
1189 complete(&addfd
->completion
);
1193 * Note that it's possible the listener died in between the time when
1194 * we were notified of a response (or a signal) and when we were able to
1195 * re-acquire the lock, so only delete from the list if the
1196 * notification actually exists.
1198 * Also note that this test is only valid because there's no way to
1199 * *reattach* to a notifier right now. If one is added, we'll need to
1200 * keep track of the notif itself and make sure they match here.
1205 mutex_unlock(&match
->notify_lock
);
1207 /* Userspace requests to continue the syscall. */
1208 if (flags
& SECCOMP_USER_NOTIF_FLAG_CONTINUE
)
1211 syscall_set_return_value(current
, current_pt_regs(),
1216 static int __seccomp_filter(int this_syscall
, const struct seccomp_data
*sd
,
1217 const bool recheck_after_trace
)
1219 u32 filter_ret
, action
;
1220 struct seccomp_filter
*match
= NULL
;
1222 struct seccomp_data sd_local
;
1225 * Make sure that any changes to mode from another thread have
1226 * been seen after SYSCALL_WORK_SECCOMP was seen.
1231 populate_seccomp_data(&sd_local
);
1235 filter_ret
= seccomp_run_filters(sd
, &match
);
1236 data
= filter_ret
& SECCOMP_RET_DATA
;
1237 action
= filter_ret
& SECCOMP_RET_ACTION_FULL
;
1240 case SECCOMP_RET_ERRNO
:
1241 /* Set low-order bits as an errno, capped at MAX_ERRNO. */
1242 if (data
> MAX_ERRNO
)
1244 syscall_set_return_value(current
, current_pt_regs(),
1248 case SECCOMP_RET_TRAP
:
1249 /* Show the handler the original registers. */
1250 syscall_rollback(current
, current_pt_regs());
1251 /* Let the filter pass back 16 bits of data. */
1252 force_sig_seccomp(this_syscall
, data
, false);
1255 case SECCOMP_RET_TRACE
:
1256 /* We've been put in this state by the ptracer already. */
1257 if (recheck_after_trace
)
1260 /* ENOSYS these calls if there is no tracer attached. */
1261 if (!ptrace_event_enabled(current
, PTRACE_EVENT_SECCOMP
)) {
1262 syscall_set_return_value(current
,
1268 /* Allow the BPF to provide the event message */
1269 ptrace_event(PTRACE_EVENT_SECCOMP
, data
);
1271 * The delivery of a fatal signal during event
1272 * notification may silently skip tracer notification,
1273 * which could leave us with a potentially unmodified
1274 * syscall that the tracer would have liked to have
1275 * changed. Since the process is about to die, we just
1276 * force the syscall to be skipped and let the signal
1277 * kill the process and correctly handle any tracer exit
1280 if (fatal_signal_pending(current
))
1282 /* Check if the tracer forced the syscall to be skipped. */
1283 this_syscall
= syscall_get_nr(current
, current_pt_regs());
1284 if (this_syscall
< 0)
1288 * Recheck the syscall, since it may have changed. This
1289 * intentionally uses a NULL struct seccomp_data to force
1290 * a reload of all registers. This does not goto skip since
1291 * a skip would have already been reported.
1293 if (__seccomp_filter(this_syscall
, NULL
, true))
1298 case SECCOMP_RET_USER_NOTIF
:
1299 if (seccomp_do_user_notification(this_syscall
, match
, sd
))
1304 case SECCOMP_RET_LOG
:
1305 seccomp_log(this_syscall
, 0, action
, true);
1308 case SECCOMP_RET_ALLOW
:
1310 * Note that the "match" filter will always be NULL for
1311 * this action since SECCOMP_RET_ALLOW is the starting
1312 * state in seccomp_run_filters().
1316 case SECCOMP_RET_KILL_THREAD
:
1317 case SECCOMP_RET_KILL_PROCESS
:
1319 current
->seccomp
.mode
= SECCOMP_MODE_DEAD
;
1320 seccomp_log(this_syscall
, SIGSYS
, action
, true);
1321 /* Dump core only if this is the last remaining thread. */
1322 if (action
!= SECCOMP_RET_KILL_THREAD
||
1323 (atomic_read(¤t
->signal
->live
) == 1)) {
1324 /* Show the original registers in the dump. */
1325 syscall_rollback(current
, current_pt_regs());
1326 /* Trigger a coredump with SIGSYS */
1327 force_sig_seccomp(this_syscall
, data
, true);
1331 return -1; /* skip the syscall go directly to signal handling */
1337 seccomp_log(this_syscall
, 0, action
, match
? match
->log
: false);
1341 static int __seccomp_filter(int this_syscall
, const struct seccomp_data
*sd
,
1342 const bool recheck_after_trace
)
1350 int __secure_computing(const struct seccomp_data
*sd
)
1352 int mode
= current
->seccomp
.mode
;
1355 if (IS_ENABLED(CONFIG_CHECKPOINT_RESTORE
) &&
1356 unlikely(current
->ptrace
& PT_SUSPEND_SECCOMP
))
1359 this_syscall
= sd
? sd
->nr
:
1360 syscall_get_nr(current
, current_pt_regs());
1363 case SECCOMP_MODE_STRICT
:
1364 __secure_computing_strict(this_syscall
); /* may call do_exit */
1366 case SECCOMP_MODE_FILTER
:
1367 return __seccomp_filter(this_syscall
, sd
, false);
1368 /* Surviving SECCOMP_RET_KILL_* must be proactively impossible. */
1369 case SECCOMP_MODE_DEAD
:
1377 #endif /* CONFIG_HAVE_ARCH_SECCOMP_FILTER */
1379 long prctl_get_seccomp(void)
1381 return current
->seccomp
.mode
;
1385 * seccomp_set_mode_strict: internal function for setting strict seccomp
1387 * Once current->seccomp.mode is non-zero, it may not be changed.
1389 * Returns 0 on success or -EINVAL on failure.
1391 static long seccomp_set_mode_strict(void)
1393 const unsigned long seccomp_mode
= SECCOMP_MODE_STRICT
;
1396 spin_lock_irq(¤t
->sighand
->siglock
);
1398 if (!seccomp_may_assign_mode(seccomp_mode
))
1404 seccomp_assign_mode(current
, seccomp_mode
, 0);
1408 spin_unlock_irq(¤t
->sighand
->siglock
);
1413 #ifdef CONFIG_SECCOMP_FILTER
1414 static void seccomp_notify_free(struct seccomp_filter
*filter
)
1416 kfree(filter
->notif
);
1417 filter
->notif
= NULL
;
1420 static void seccomp_notify_detach(struct seccomp_filter
*filter
)
1422 struct seccomp_knotif
*knotif
;
1427 mutex_lock(&filter
->notify_lock
);
1430 * If this file is being closed because e.g. the task who owned it
1431 * died, let's wake everyone up who was waiting on us.
1433 list_for_each_entry(knotif
, &filter
->notif
->notifications
, list
) {
1434 if (knotif
->state
== SECCOMP_NOTIFY_REPLIED
)
1437 knotif
->state
= SECCOMP_NOTIFY_REPLIED
;
1438 knotif
->error
= -ENOSYS
;
1442 * We do not need to wake up any pending addfd messages, as
1443 * the notifier will do that for us, as this just looks
1444 * like a standard reply.
1446 complete(&knotif
->ready
);
1449 seccomp_notify_free(filter
);
1450 mutex_unlock(&filter
->notify_lock
);
1453 static int seccomp_notify_release(struct inode
*inode
, struct file
*file
)
1455 struct seccomp_filter
*filter
= file
->private_data
;
1457 seccomp_notify_detach(filter
);
1458 __put_seccomp_filter(filter
);
1462 /* must be called with notif_lock held */
1463 static inline struct seccomp_knotif
*
1464 find_notification(struct seccomp_filter
*filter
, u64 id
)
1466 struct seccomp_knotif
*cur
;
1468 lockdep_assert_held(&filter
->notify_lock
);
1470 list_for_each_entry(cur
, &filter
->notif
->notifications
, list
) {
1478 static int recv_wake_function(wait_queue_entry_t
*wait
, unsigned int mode
, int sync
,
1481 /* Avoid a wakeup if event not interesting for us. */
1482 if (key
&& !(key_to_poll(key
) & (EPOLLIN
| EPOLLERR
| EPOLLHUP
)))
1484 return autoremove_wake_function(wait
, mode
, sync
, key
);
1487 static int recv_wait_event(struct seccomp_filter
*filter
)
1489 DEFINE_WAIT_FUNC(wait
, recv_wake_function
);
1492 if (refcount_read(&filter
->users
) == 0)
1495 if (atomic_dec_if_positive(&filter
->notif
->requests
) >= 0)
1499 ret
= prepare_to_wait_event(&filter
->wqh
, &wait
, TASK_INTERRUPTIBLE
);
1501 if (atomic_dec_if_positive(&filter
->notif
->requests
) >= 0)
1503 if (refcount_read(&filter
->users
) == 0)
1511 finish_wait(&filter
->wqh
, &wait
);
1515 static long seccomp_notify_recv(struct seccomp_filter
*filter
,
1518 struct seccomp_knotif
*knotif
= NULL
, *cur
;
1519 struct seccomp_notif unotif
;
1522 /* Verify that we're not given garbage to keep struct extensible. */
1523 ret
= check_zeroed_user(buf
, sizeof(unotif
));
1529 memset(&unotif
, 0, sizeof(unotif
));
1531 ret
= recv_wait_event(filter
);
1535 mutex_lock(&filter
->notify_lock
);
1536 list_for_each_entry(cur
, &filter
->notif
->notifications
, list
) {
1537 if (cur
->state
== SECCOMP_NOTIFY_INIT
) {
1544 * If we didn't find a notification, it could be that the task was
1545 * interrupted by a fatal signal between the time we were woken and
1546 * when we were able to acquire the rw lock.
1553 unotif
.id
= knotif
->id
;
1554 unotif
.pid
= task_pid_vnr(knotif
->task
);
1555 unotif
.data
= *(knotif
->data
);
1557 knotif
->state
= SECCOMP_NOTIFY_SENT
;
1558 wake_up_poll(&filter
->wqh
, EPOLLOUT
| EPOLLWRNORM
);
1561 mutex_unlock(&filter
->notify_lock
);
1563 if (ret
== 0 && copy_to_user(buf
, &unotif
, sizeof(unotif
))) {
1567 * Userspace screwed up. To make sure that we keep this
1568 * notification alive, let's reset it back to INIT. It
1569 * may have died when we released the lock, so we need to make
1570 * sure it's still around.
1572 mutex_lock(&filter
->notify_lock
);
1573 knotif
= find_notification(filter
, unotif
.id
);
1575 /* Reset the process to make sure it's not stuck */
1576 if (should_sleep_killable(filter
, knotif
))
1577 complete(&knotif
->ready
);
1578 knotif
->state
= SECCOMP_NOTIFY_INIT
;
1579 atomic_inc(&filter
->notif
->requests
);
1580 wake_up_poll(&filter
->wqh
, EPOLLIN
| EPOLLRDNORM
);
1582 mutex_unlock(&filter
->notify_lock
);
1588 static long seccomp_notify_send(struct seccomp_filter
*filter
,
1591 struct seccomp_notif_resp resp
= {};
1592 struct seccomp_knotif
*knotif
;
1595 if (copy_from_user(&resp
, buf
, sizeof(resp
)))
1598 if (resp
.flags
& ~SECCOMP_USER_NOTIF_FLAG_CONTINUE
)
1601 if ((resp
.flags
& SECCOMP_USER_NOTIF_FLAG_CONTINUE
) &&
1602 (resp
.error
|| resp
.val
))
1605 ret
= mutex_lock_interruptible(&filter
->notify_lock
);
1609 knotif
= find_notification(filter
, resp
.id
);
1615 /* Allow exactly one reply. */
1616 if (knotif
->state
!= SECCOMP_NOTIFY_SENT
) {
1622 knotif
->state
= SECCOMP_NOTIFY_REPLIED
;
1623 knotif
->error
= resp
.error
;
1624 knotif
->val
= resp
.val
;
1625 knotif
->flags
= resp
.flags
;
1626 if (filter
->notif
->flags
& SECCOMP_USER_NOTIF_FD_SYNC_WAKE_UP
)
1627 complete_on_current_cpu(&knotif
->ready
);
1629 complete(&knotif
->ready
);
1631 mutex_unlock(&filter
->notify_lock
);
1635 static long seccomp_notify_id_valid(struct seccomp_filter
*filter
,
1638 struct seccomp_knotif
*knotif
;
1642 if (copy_from_user(&id
, buf
, sizeof(id
)))
1645 ret
= mutex_lock_interruptible(&filter
->notify_lock
);
1649 knotif
= find_notification(filter
, id
);
1650 if (knotif
&& knotif
->state
== SECCOMP_NOTIFY_SENT
)
1655 mutex_unlock(&filter
->notify_lock
);
1659 static long seccomp_notify_set_flags(struct seccomp_filter
*filter
,
1660 unsigned long flags
)
1664 if (flags
& ~SECCOMP_USER_NOTIF_FD_SYNC_WAKE_UP
)
1667 ret
= mutex_lock_interruptible(&filter
->notify_lock
);
1670 filter
->notif
->flags
= flags
;
1671 mutex_unlock(&filter
->notify_lock
);
1675 static long seccomp_notify_addfd(struct seccomp_filter
*filter
,
1676 struct seccomp_notif_addfd __user
*uaddfd
,
1679 struct seccomp_notif_addfd addfd
;
1680 struct seccomp_knotif
*knotif
;
1681 struct seccomp_kaddfd kaddfd
;
1684 BUILD_BUG_ON(sizeof(addfd
) < SECCOMP_NOTIFY_ADDFD_SIZE_VER0
);
1685 BUILD_BUG_ON(sizeof(addfd
) != SECCOMP_NOTIFY_ADDFD_SIZE_LATEST
);
1687 if (size
< SECCOMP_NOTIFY_ADDFD_SIZE_VER0
|| size
>= PAGE_SIZE
)
1690 ret
= copy_struct_from_user(&addfd
, sizeof(addfd
), uaddfd
, size
);
1694 if (addfd
.newfd_flags
& ~O_CLOEXEC
)
1697 if (addfd
.flags
& ~(SECCOMP_ADDFD_FLAG_SETFD
| SECCOMP_ADDFD_FLAG_SEND
))
1700 if (addfd
.newfd
&& !(addfd
.flags
& SECCOMP_ADDFD_FLAG_SETFD
))
1703 kaddfd
.file
= fget(addfd
.srcfd
);
1707 kaddfd
.ioctl_flags
= addfd
.flags
;
1708 kaddfd
.flags
= addfd
.newfd_flags
;
1709 kaddfd
.setfd
= addfd
.flags
& SECCOMP_ADDFD_FLAG_SETFD
;
1710 kaddfd
.fd
= addfd
.newfd
;
1711 init_completion(&kaddfd
.completion
);
1713 ret
= mutex_lock_interruptible(&filter
->notify_lock
);
1717 knotif
= find_notification(filter
, addfd
.id
);
1724 * We do not want to allow for FD injection to occur before the
1725 * notification has been picked up by a userspace handler, or after
1726 * the notification has been replied to.
1728 if (knotif
->state
!= SECCOMP_NOTIFY_SENT
) {
1733 if (addfd
.flags
& SECCOMP_ADDFD_FLAG_SEND
) {
1735 * Disallow queuing an atomic addfd + send reply while there are
1736 * some addfd requests still to process.
1738 * There is no clear reason to support it and allows us to keep
1739 * the loop on the other side straight-forward.
1741 if (!list_empty(&knotif
->addfd
)) {
1746 /* Allow exactly only one reply */
1747 knotif
->state
= SECCOMP_NOTIFY_REPLIED
;
1750 list_add(&kaddfd
.list
, &knotif
->addfd
);
1751 complete(&knotif
->ready
);
1752 mutex_unlock(&filter
->notify_lock
);
1754 /* Now we wait for it to be processed or be interrupted */
1755 ret
= wait_for_completion_interruptible(&kaddfd
.completion
);
1758 * We had a successful completion. The other side has already
1759 * removed us from the addfd queue, and
1760 * wait_for_completion_interruptible has a memory barrier upon
1761 * success that lets us read this value directly without
1768 mutex_lock(&filter
->notify_lock
);
1770 * Even though we were woken up by a signal and not a successful
1771 * completion, a completion may have happened in the mean time.
1773 * We need to check again if the addfd request has been handled,
1774 * and if not, we will remove it from the queue.
1776 if (list_empty(&kaddfd
.list
))
1779 list_del(&kaddfd
.list
);
1782 mutex_unlock(&filter
->notify_lock
);
1789 static long seccomp_notify_ioctl(struct file
*file
, unsigned int cmd
,
1792 struct seccomp_filter
*filter
= file
->private_data
;
1793 void __user
*buf
= (void __user
*)arg
;
1795 /* Fixed-size ioctls */
1797 case SECCOMP_IOCTL_NOTIF_RECV
:
1798 return seccomp_notify_recv(filter
, buf
);
1799 case SECCOMP_IOCTL_NOTIF_SEND
:
1800 return seccomp_notify_send(filter
, buf
);
1801 case SECCOMP_IOCTL_NOTIF_ID_VALID_WRONG_DIR
:
1802 case SECCOMP_IOCTL_NOTIF_ID_VALID
:
1803 return seccomp_notify_id_valid(filter
, buf
);
1804 case SECCOMP_IOCTL_NOTIF_SET_FLAGS
:
1805 return seccomp_notify_set_flags(filter
, arg
);
1808 /* Extensible Argument ioctls */
1809 #define EA_IOCTL(cmd) ((cmd) & ~(IOC_INOUT | IOCSIZE_MASK))
1810 switch (EA_IOCTL(cmd
)) {
1811 case EA_IOCTL(SECCOMP_IOCTL_NOTIF_ADDFD
):
1812 return seccomp_notify_addfd(filter
, buf
, _IOC_SIZE(cmd
));
1818 static __poll_t
seccomp_notify_poll(struct file
*file
,
1819 struct poll_table_struct
*poll_tab
)
1821 struct seccomp_filter
*filter
= file
->private_data
;
1823 struct seccomp_knotif
*cur
;
1825 poll_wait(file
, &filter
->wqh
, poll_tab
);
1827 if (mutex_lock_interruptible(&filter
->notify_lock
) < 0)
1830 list_for_each_entry(cur
, &filter
->notif
->notifications
, list
) {
1831 if (cur
->state
== SECCOMP_NOTIFY_INIT
)
1832 ret
|= EPOLLIN
| EPOLLRDNORM
;
1833 if (cur
->state
== SECCOMP_NOTIFY_SENT
)
1834 ret
|= EPOLLOUT
| EPOLLWRNORM
;
1835 if ((ret
& EPOLLIN
) && (ret
& EPOLLOUT
))
1839 mutex_unlock(&filter
->notify_lock
);
1841 if (refcount_read(&filter
->users
) == 0)
1847 static const struct file_operations seccomp_notify_ops
= {
1848 .poll
= seccomp_notify_poll
,
1849 .release
= seccomp_notify_release
,
1850 .unlocked_ioctl
= seccomp_notify_ioctl
,
1851 .compat_ioctl
= seccomp_notify_ioctl
,
1854 static struct file
*init_listener(struct seccomp_filter
*filter
)
1858 ret
= ERR_PTR(-ENOMEM
);
1859 filter
->notif
= kzalloc(sizeof(*(filter
->notif
)), GFP_KERNEL
);
1863 filter
->notif
->next_id
= get_random_u64();
1864 INIT_LIST_HEAD(&filter
->notif
->notifications
);
1866 ret
= anon_inode_getfile("seccomp notify", &seccomp_notify_ops
,
1871 /* The file has a reference to it now */
1872 __get_seccomp_filter(filter
);
1876 seccomp_notify_free(filter
);
1882 * Does @new_child have a listener while an ancestor also has a listener?
1883 * If so, we'll want to reject this filter.
1884 * This only has to be tested for the current process, even in the TSYNC case,
1885 * because TSYNC installs @child with the same parent on all threads.
1886 * Note that @new_child is not hooked up to its parent at this point yet, so
1887 * we use current->seccomp.filter.
1889 static bool has_duplicate_listener(struct seccomp_filter
*new_child
)
1891 struct seccomp_filter
*cur
;
1893 /* must be protected against concurrent TSYNC */
1894 lockdep_assert_held(¤t
->sighand
->siglock
);
1896 if (!new_child
->notif
)
1898 for (cur
= current
->seccomp
.filter
; cur
; cur
= cur
->prev
) {
1907 * seccomp_set_mode_filter: internal function for setting seccomp filter
1908 * @flags: flags to change filter behavior
1909 * @filter: struct sock_fprog containing filter
1911 * This function may be called repeatedly to install additional filters.
1912 * Every filter successfully installed will be evaluated (in reverse order)
1913 * for each system call the task makes.
1915 * Once current->seccomp.mode is non-zero, it may not be changed.
1917 * Returns 0 on success or -EINVAL on failure.
1919 static long seccomp_set_mode_filter(unsigned int flags
,
1920 const char __user
*filter
)
1922 const unsigned long seccomp_mode
= SECCOMP_MODE_FILTER
;
1923 struct seccomp_filter
*prepared
= NULL
;
1926 struct file
*listener_f
= NULL
;
1928 /* Validate flags. */
1929 if (flags
& ~SECCOMP_FILTER_FLAG_MASK
)
1933 * In the successful case, NEW_LISTENER returns the new listener fd.
1934 * But in the failure case, TSYNC returns the thread that died. If you
1935 * combine these two flags, there's no way to tell whether something
1936 * succeeded or failed. So, let's disallow this combination if the user
1937 * has not explicitly requested no errors from TSYNC.
1939 if ((flags
& SECCOMP_FILTER_FLAG_TSYNC
) &&
1940 (flags
& SECCOMP_FILTER_FLAG_NEW_LISTENER
) &&
1941 ((flags
& SECCOMP_FILTER_FLAG_TSYNC_ESRCH
) == 0))
1945 * The SECCOMP_FILTER_FLAG_WAIT_KILLABLE_SENT flag doesn't make sense
1946 * without the SECCOMP_FILTER_FLAG_NEW_LISTENER flag.
1948 if ((flags
& SECCOMP_FILTER_FLAG_WAIT_KILLABLE_RECV
) &&
1949 ((flags
& SECCOMP_FILTER_FLAG_NEW_LISTENER
) == 0))
1952 /* Prepare the new filter before holding any locks. */
1953 prepared
= seccomp_prepare_user_filter(filter
);
1954 if (IS_ERR(prepared
))
1955 return PTR_ERR(prepared
);
1957 if (flags
& SECCOMP_FILTER_FLAG_NEW_LISTENER
) {
1958 listener
= get_unused_fd_flags(O_CLOEXEC
);
1964 listener_f
= init_listener(prepared
);
1965 if (IS_ERR(listener_f
)) {
1966 put_unused_fd(listener
);
1967 ret
= PTR_ERR(listener_f
);
1973 * Make sure we cannot change seccomp or nnp state via TSYNC
1974 * while another thread is in the middle of calling exec.
1976 if (flags
& SECCOMP_FILTER_FLAG_TSYNC
&&
1977 mutex_lock_killable(¤t
->signal
->cred_guard_mutex
))
1980 spin_lock_irq(¤t
->sighand
->siglock
);
1982 if (!seccomp_may_assign_mode(seccomp_mode
))
1985 if (has_duplicate_listener(prepared
)) {
1990 ret
= seccomp_attach_filter(flags
, prepared
);
1993 /* Do not free the successfully attached filter. */
1996 seccomp_assign_mode(current
, seccomp_mode
, flags
);
1998 spin_unlock_irq(¤t
->sighand
->siglock
);
1999 if (flags
& SECCOMP_FILTER_FLAG_TSYNC
)
2000 mutex_unlock(¤t
->signal
->cred_guard_mutex
);
2002 if (flags
& SECCOMP_FILTER_FLAG_NEW_LISTENER
) {
2004 listener_f
->private_data
= NULL
;
2006 put_unused_fd(listener
);
2007 seccomp_notify_detach(prepared
);
2009 fd_install(listener
, listener_f
);
2014 seccomp_filter_free(prepared
);
2018 static inline long seccomp_set_mode_filter(unsigned int flags
,
2019 const char __user
*filter
)
2025 static long seccomp_get_action_avail(const char __user
*uaction
)
2029 if (copy_from_user(&action
, uaction
, sizeof(action
)))
2033 case SECCOMP_RET_KILL_PROCESS
:
2034 case SECCOMP_RET_KILL_THREAD
:
2035 case SECCOMP_RET_TRAP
:
2036 case SECCOMP_RET_ERRNO
:
2037 case SECCOMP_RET_USER_NOTIF
:
2038 case SECCOMP_RET_TRACE
:
2039 case SECCOMP_RET_LOG
:
2040 case SECCOMP_RET_ALLOW
:
2049 static long seccomp_get_notif_sizes(void __user
*usizes
)
2051 struct seccomp_notif_sizes sizes
= {
2052 .seccomp_notif
= sizeof(struct seccomp_notif
),
2053 .seccomp_notif_resp
= sizeof(struct seccomp_notif_resp
),
2054 .seccomp_data
= sizeof(struct seccomp_data
),
2057 if (copy_to_user(usizes
, &sizes
, sizeof(sizes
)))
2063 /* Common entry point for both prctl and syscall. */
2064 static long do_seccomp(unsigned int op
, unsigned int flags
,
2068 case SECCOMP_SET_MODE_STRICT
:
2069 if (flags
!= 0 || uargs
!= NULL
)
2071 return seccomp_set_mode_strict();
2072 case SECCOMP_SET_MODE_FILTER
:
2073 return seccomp_set_mode_filter(flags
, uargs
);
2074 case SECCOMP_GET_ACTION_AVAIL
:
2078 return seccomp_get_action_avail(uargs
);
2079 case SECCOMP_GET_NOTIF_SIZES
:
2083 return seccomp_get_notif_sizes(uargs
);
2089 SYSCALL_DEFINE3(seccomp
, unsigned int, op
, unsigned int, flags
,
2090 void __user
*, uargs
)
2092 return do_seccomp(op
, flags
, uargs
);
2096 * prctl_set_seccomp: configures current->seccomp.mode
2097 * @seccomp_mode: requested mode to use
2098 * @filter: optional struct sock_fprog for use with SECCOMP_MODE_FILTER
2100 * Returns 0 on success or -EINVAL on failure.
2102 long prctl_set_seccomp(unsigned long seccomp_mode
, void __user
*filter
)
2107 switch (seccomp_mode
) {
2108 case SECCOMP_MODE_STRICT
:
2109 op
= SECCOMP_SET_MODE_STRICT
;
2111 * Setting strict mode through prctl always ignored filter,
2112 * so make sure it is always NULL here to pass the internal
2113 * check in do_seccomp().
2117 case SECCOMP_MODE_FILTER
:
2118 op
= SECCOMP_SET_MODE_FILTER
;
2125 /* prctl interface doesn't have flags, so they are always zero. */
2126 return do_seccomp(op
, 0, uargs
);
2129 #if defined(CONFIG_SECCOMP_FILTER) && defined(CONFIG_CHECKPOINT_RESTORE)
2130 static struct seccomp_filter
*get_nth_filter(struct task_struct
*task
,
2131 unsigned long filter_off
)
2133 struct seccomp_filter
*orig
, *filter
;
2134 unsigned long count
;
2137 * Note: this is only correct because the caller should be the (ptrace)
2138 * tracer of the task, otherwise lock_task_sighand is needed.
2140 spin_lock_irq(&task
->sighand
->siglock
);
2142 if (task
->seccomp
.mode
!= SECCOMP_MODE_FILTER
) {
2143 spin_unlock_irq(&task
->sighand
->siglock
);
2144 return ERR_PTR(-EINVAL
);
2147 orig
= task
->seccomp
.filter
;
2148 __get_seccomp_filter(orig
);
2149 spin_unlock_irq(&task
->sighand
->siglock
);
2152 for (filter
= orig
; filter
; filter
= filter
->prev
)
2155 if (filter_off
>= count
) {
2156 filter
= ERR_PTR(-ENOENT
);
2160 count
-= filter_off
;
2161 for (filter
= orig
; filter
&& count
> 1; filter
= filter
->prev
)
2164 if (WARN_ON(count
!= 1 || !filter
)) {
2165 filter
= ERR_PTR(-ENOENT
);
2169 __get_seccomp_filter(filter
);
2172 __put_seccomp_filter(orig
);
2176 long seccomp_get_filter(struct task_struct
*task
, unsigned long filter_off
,
2179 struct seccomp_filter
*filter
;
2180 struct sock_fprog_kern
*fprog
;
2183 if (!capable(CAP_SYS_ADMIN
) ||
2184 current
->seccomp
.mode
!= SECCOMP_MODE_DISABLED
) {
2188 filter
= get_nth_filter(task
, filter_off
);
2190 return PTR_ERR(filter
);
2192 fprog
= filter
->prog
->orig_prog
;
2194 /* This must be a new non-cBPF filter, since we save
2195 * every cBPF filter's orig_prog above when
2196 * CONFIG_CHECKPOINT_RESTORE is enabled.
2206 if (copy_to_user(data
, fprog
->filter
, bpf_classic_proglen(fprog
)))
2210 __put_seccomp_filter(filter
);
2214 long seccomp_get_metadata(struct task_struct
*task
,
2215 unsigned long size
, void __user
*data
)
2218 struct seccomp_filter
*filter
;
2219 struct seccomp_metadata kmd
= {};
2221 if (!capable(CAP_SYS_ADMIN
) ||
2222 current
->seccomp
.mode
!= SECCOMP_MODE_DISABLED
) {
2226 size
= min_t(unsigned long, size
, sizeof(kmd
));
2228 if (size
< sizeof(kmd
.filter_off
))
2231 if (copy_from_user(&kmd
.filter_off
, data
, sizeof(kmd
.filter_off
)))
2234 filter
= get_nth_filter(task
, kmd
.filter_off
);
2236 return PTR_ERR(filter
);
2239 kmd
.flags
|= SECCOMP_FILTER_FLAG_LOG
;
2242 if (copy_to_user(data
, &kmd
, size
))
2245 __put_seccomp_filter(filter
);
2250 #ifdef CONFIG_SYSCTL
2252 /* Human readable action names for friendly sysctl interaction */
2253 #define SECCOMP_RET_KILL_PROCESS_NAME "kill_process"
2254 #define SECCOMP_RET_KILL_THREAD_NAME "kill_thread"
2255 #define SECCOMP_RET_TRAP_NAME "trap"
2256 #define SECCOMP_RET_ERRNO_NAME "errno"
2257 #define SECCOMP_RET_USER_NOTIF_NAME "user_notif"
2258 #define SECCOMP_RET_TRACE_NAME "trace"
2259 #define SECCOMP_RET_LOG_NAME "log"
2260 #define SECCOMP_RET_ALLOW_NAME "allow"
2262 static const char seccomp_actions_avail
[] =
2263 SECCOMP_RET_KILL_PROCESS_NAME
" "
2264 SECCOMP_RET_KILL_THREAD_NAME
" "
2265 SECCOMP_RET_TRAP_NAME
" "
2266 SECCOMP_RET_ERRNO_NAME
" "
2267 SECCOMP_RET_USER_NOTIF_NAME
" "
2268 SECCOMP_RET_TRACE_NAME
" "
2269 SECCOMP_RET_LOG_NAME
" "
2270 SECCOMP_RET_ALLOW_NAME
;
2272 struct seccomp_log_name
{
2277 static const struct seccomp_log_name seccomp_log_names
[] = {
2278 { SECCOMP_LOG_KILL_PROCESS
, SECCOMP_RET_KILL_PROCESS_NAME
},
2279 { SECCOMP_LOG_KILL_THREAD
, SECCOMP_RET_KILL_THREAD_NAME
},
2280 { SECCOMP_LOG_TRAP
, SECCOMP_RET_TRAP_NAME
},
2281 { SECCOMP_LOG_ERRNO
, SECCOMP_RET_ERRNO_NAME
},
2282 { SECCOMP_LOG_USER_NOTIF
, SECCOMP_RET_USER_NOTIF_NAME
},
2283 { SECCOMP_LOG_TRACE
, SECCOMP_RET_TRACE_NAME
},
2284 { SECCOMP_LOG_LOG
, SECCOMP_RET_LOG_NAME
},
2285 { SECCOMP_LOG_ALLOW
, SECCOMP_RET_ALLOW_NAME
},
2289 static bool seccomp_names_from_actions_logged(char *names
, size_t size
,
2293 const struct seccomp_log_name
*cur
;
2294 bool append_sep
= false;
2296 for (cur
= seccomp_log_names
; cur
->name
&& size
; cur
++) {
2299 if (!(actions_logged
& cur
->log
))
2303 ret
= strscpy(names
, sep
, size
);
2312 ret
= strscpy(names
, cur
->name
, size
);
2323 static bool seccomp_action_logged_from_name(u32
*action_logged
,
2326 const struct seccomp_log_name
*cur
;
2328 for (cur
= seccomp_log_names
; cur
->name
; cur
++) {
2329 if (!strcmp(cur
->name
, name
)) {
2330 *action_logged
= cur
->log
;
2338 static bool seccomp_actions_logged_from_names(u32
*actions_logged
, char *names
)
2342 *actions_logged
= 0;
2343 while ((name
= strsep(&names
, " ")) && *name
) {
2344 u32 action_logged
= 0;
2346 if (!seccomp_action_logged_from_name(&action_logged
, name
))
2349 *actions_logged
|= action_logged
;
2355 static int read_actions_logged(const struct ctl_table
*ro_table
, void *buffer
,
2356 size_t *lenp
, loff_t
*ppos
)
2358 char names
[sizeof(seccomp_actions_avail
)];
2359 struct ctl_table table
;
2361 memset(names
, 0, sizeof(names
));
2363 if (!seccomp_names_from_actions_logged(names
, sizeof(names
),
2364 seccomp_actions_logged
, " "))
2369 table
.maxlen
= sizeof(names
);
2370 return proc_dostring(&table
, 0, buffer
, lenp
, ppos
);
2373 static int write_actions_logged(const struct ctl_table
*ro_table
, void *buffer
,
2374 size_t *lenp
, loff_t
*ppos
, u32
*actions_logged
)
2376 char names
[sizeof(seccomp_actions_avail
)];
2377 struct ctl_table table
;
2380 if (!capable(CAP_SYS_ADMIN
))
2383 memset(names
, 0, sizeof(names
));
2387 table
.maxlen
= sizeof(names
);
2388 ret
= proc_dostring(&table
, 1, buffer
, lenp
, ppos
);
2392 if (!seccomp_actions_logged_from_names(actions_logged
, table
.data
))
2395 if (*actions_logged
& SECCOMP_LOG_ALLOW
)
2398 seccomp_actions_logged
= *actions_logged
;
2402 static void audit_actions_logged(u32 actions_logged
, u32 old_actions_logged
,
2405 char names
[sizeof(seccomp_actions_avail
)];
2406 char old_names
[sizeof(seccomp_actions_avail
)];
2407 const char *new = names
;
2408 const char *old
= old_names
;
2413 memset(names
, 0, sizeof(names
));
2414 memset(old_names
, 0, sizeof(old_names
));
2418 else if (!actions_logged
)
2420 else if (!seccomp_names_from_actions_logged(names
, sizeof(names
),
2421 actions_logged
, ","))
2424 if (!old_actions_logged
)
2426 else if (!seccomp_names_from_actions_logged(old_names
,
2428 old_actions_logged
, ","))
2431 return audit_seccomp_actions_logged(new, old
, !ret
);
2434 static int seccomp_actions_logged_handler(const struct ctl_table
*ro_table
, int write
,
2435 void *buffer
, size_t *lenp
,
2441 u32 actions_logged
= 0;
2442 u32 old_actions_logged
= seccomp_actions_logged
;
2444 ret
= write_actions_logged(ro_table
, buffer
, lenp
, ppos
,
2446 audit_actions_logged(actions_logged
, old_actions_logged
, ret
);
2448 ret
= read_actions_logged(ro_table
, buffer
, lenp
, ppos
);
2453 static struct ctl_table seccomp_sysctl_table
[] = {
2455 .procname
= "actions_avail",
2456 .data
= (void *) &seccomp_actions_avail
,
2457 .maxlen
= sizeof(seccomp_actions_avail
),
2459 .proc_handler
= proc_dostring
,
2462 .procname
= "actions_logged",
2464 .proc_handler
= seccomp_actions_logged_handler
,
2468 static int __init
seccomp_sysctl_init(void)
2470 register_sysctl_init("kernel/seccomp", seccomp_sysctl_table
);
2474 device_initcall(seccomp_sysctl_init
)
2476 #endif /* CONFIG_SYSCTL */
2478 #ifdef CONFIG_SECCOMP_CACHE_DEBUG
2479 /* Currently CONFIG_SECCOMP_CACHE_DEBUG implies SECCOMP_ARCH_NATIVE */
2480 static void proc_pid_seccomp_cache_arch(struct seq_file
*m
, const char *name
,
2481 const void *bitmap
, size_t bitmap_size
)
2485 for (nr
= 0; nr
< bitmap_size
; nr
++) {
2486 bool cached
= test_bit(nr
, bitmap
);
2487 char *status
= cached
? "ALLOW" : "FILTER";
2489 seq_printf(m
, "%s %d %s\n", name
, nr
, status
);
2493 int proc_pid_seccomp_cache(struct seq_file
*m
, struct pid_namespace
*ns
,
2494 struct pid
*pid
, struct task_struct
*task
)
2496 struct seccomp_filter
*f
;
2497 unsigned long flags
;
2500 * We don't want some sandboxed process to know what their seccomp
2501 * filters consist of.
2503 if (!file_ns_capable(m
->file
, &init_user_ns
, CAP_SYS_ADMIN
))
2506 if (!lock_task_sighand(task
, &flags
))
2509 f
= READ_ONCE(task
->seccomp
.filter
);
2511 unlock_task_sighand(task
, &flags
);
2515 /* prevent filter from being freed while we are printing it */
2516 __get_seccomp_filter(f
);
2517 unlock_task_sighand(task
, &flags
);
2519 proc_pid_seccomp_cache_arch(m
, SECCOMP_ARCH_NATIVE_NAME
,
2520 f
->cache
.allow_native
,
2521 SECCOMP_ARCH_NATIVE_NR
);
2523 #ifdef SECCOMP_ARCH_COMPAT
2524 proc_pid_seccomp_cache_arch(m
, SECCOMP_ARCH_COMPAT_NAME
,
2525 f
->cache
.allow_compat
,
2526 SECCOMP_ARCH_COMPAT_NR
);
2527 #endif /* SECCOMP_ARCH_COMPAT */
2529 __put_seccomp_filter(f
);
2532 #endif /* CONFIG_SECCOMP_CACHE_DEBUG */