]>
Commit | Line | Data |
---|---|---|
b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
2 | /* |
3 | * linux/kernel/seccomp.c | |
4 | * | |
5 | * Copyright 2004-2005 Andrea Arcangeli <andrea@cpushare.com> | |
6 | * | |
e2cfabdf WD |
7 | * Copyright (C) 2012 Google, Inc. |
8 | * Will Drewry <wad@chromium.org> | |
9 | * | |
10 | * This defines a simple but solid secure-computing facility. | |
11 | * | |
12 | * Mode 1 uses a fixed list of allowed system calls. | |
13 | * Mode 2 allows user-defined system call filters in the form | |
14 | * of Berkeley Packet Filters/Linux Socket Filters. | |
1da177e4 | 15 | */ |
e68f9d49 | 16 | #define pr_fmt(fmt) "seccomp: " fmt |
1da177e4 | 17 | |
0b5fa229 | 18 | #include <linux/refcount.h> |
85e7bac3 | 19 | #include <linux/audit.h> |
5b101740 | 20 | #include <linux/compat.h> |
b25e6716 | 21 | #include <linux/coredump.h> |
8e5f1ad1 | 22 | #include <linux/kmemleak.h> |
5c307089 KC |
23 | #include <linux/nospec.h> |
24 | #include <linux/prctl.h> | |
e2cfabdf | 25 | #include <linux/sched.h> |
68db0cf1 | 26 | #include <linux/sched/task_stack.h> |
e2cfabdf | 27 | #include <linux/seccomp.h> |
c8bee430 | 28 | #include <linux/slab.h> |
48dc92b9 | 29 | #include <linux/syscalls.h> |
8e5f1ad1 | 30 | #include <linux/sysctl.h> |
1da177e4 | 31 | |
a4412fc9 | 32 | #ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER |
e2cfabdf | 33 | #include <asm/syscall.h> |
a4412fc9 | 34 | #endif |
e2cfabdf WD |
35 | |
36 | #ifdef CONFIG_SECCOMP_FILTER | |
6a21cc50 | 37 | #include <linux/file.h> |
e2cfabdf | 38 | #include <linux/filter.h> |
c2e1f2e3 | 39 | #include <linux/pid.h> |
fb0fadf9 | 40 | #include <linux/ptrace.h> |
e2cfabdf | 41 | #include <linux/security.h> |
e2cfabdf WD |
42 | #include <linux/tracehook.h> |
43 | #include <linux/uaccess.h> | |
6a21cc50 | 44 | #include <linux/anon_inodes.h> |
9f87dcf1 | 45 | #include <linux/lockdep.h> |
6a21cc50 | 46 | |
47e33c05 KC |
47 | /* |
48 | * When SECCOMP_IOCTL_NOTIF_ID_VALID was first introduced, it had the | |
49 | * wrong direction flag in the ioctl number. This is the broken one, | |
50 | * which the kernel needs to keep supporting until all userspaces stop | |
51 | * using the wrong command number. | |
52 | */ | |
53 | #define SECCOMP_IOCTL_NOTIF_ID_VALID_WRONG_DIR SECCOMP_IOR(2, __u64) | |
54 | ||
6a21cc50 TA |
55 | enum notify_state { |
56 | SECCOMP_NOTIFY_INIT, | |
57 | SECCOMP_NOTIFY_SENT, | |
58 | SECCOMP_NOTIFY_REPLIED, | |
59 | }; | |
60 | ||
61 | struct seccomp_knotif { | |
62 | /* The struct pid of the task whose filter triggered the notification */ | |
63 | struct task_struct *task; | |
64 | ||
65 | /* The "cookie" for this request; this is unique for this filter. */ | |
66 | u64 id; | |
67 | ||
68 | /* | |
69 | * The seccomp data. This pointer is valid the entire time this | |
70 | * notification is active, since it comes from __seccomp_filter which | |
71 | * eclipses the entire lifecycle here. | |
72 | */ | |
73 | const struct seccomp_data *data; | |
74 | ||
75 | /* | |
76 | * Notification states. When SECCOMP_RET_USER_NOTIF is returned, a | |
77 | * struct seccomp_knotif is created and starts out in INIT. Once the | |
78 | * handler reads the notification off of an FD, it transitions to SENT. | |
79 | * If a signal is received the state transitions back to INIT and | |
80 | * another message is sent. When the userspace handler replies, state | |
81 | * transitions to REPLIED. | |
82 | */ | |
83 | enum notify_state state; | |
84 | ||
85 | /* The return values, only valid when in SECCOMP_NOTIFY_REPLIED */ | |
86 | int error; | |
87 | long val; | |
fb3c5386 | 88 | u32 flags; |
6a21cc50 | 89 | |
7cf97b12 SD |
90 | /* |
91 | * Signals when this has changed states, such as the listener | |
92 | * dying, a new seccomp addfd message, or changing to REPLIED | |
93 | */ | |
6a21cc50 TA |
94 | struct completion ready; |
95 | ||
96 | struct list_head list; | |
7cf97b12 SD |
97 | |
98 | /* outstanding addfd requests */ | |
99 | struct list_head addfd; | |
100 | }; | |
101 | ||
102 | /** | |
103 | * struct seccomp_kaddfd - container for seccomp_addfd ioctl messages | |
104 | * | |
105 | * @file: A reference to the file to install in the other task | |
106 | * @fd: The fd number to install it at. If the fd number is -1, it means the | |
107 | * installing process should allocate the fd as normal. | |
108 | * @flags: The flags for the new file descriptor. At the moment, only O_CLOEXEC | |
109 | * is allowed. | |
110 | * @ret: The return value of the installing process. It is set to the fd num | |
111 | * upon success (>= 0). | |
112 | * @completion: Indicates that the installing process has completed fd | |
113 | * installation, or gone away (either due to successful | |
114 | * reply, or signal) | |
115 | * | |
116 | */ | |
117 | struct seccomp_kaddfd { | |
118 | struct file *file; | |
119 | int fd; | |
120 | unsigned int flags; | |
121 | ||
122 | /* To only be set on reply */ | |
123 | int ret; | |
124 | struct completion completion; | |
125 | struct list_head list; | |
6a21cc50 TA |
126 | }; |
127 | ||
128 | /** | |
129 | * struct notification - container for seccomp userspace notifications. Since | |
130 | * most seccomp filters will not have notification listeners attached and this | |
131 | * structure is fairly large, we store the notification-specific stuff in a | |
132 | * separate structure. | |
133 | * | |
134 | * @request: A semaphore that users of this notification can wait on for | |
135 | * changes. Actual reads and writes are still controlled with | |
136 | * filter->notify_lock. | |
137 | * @next_id: The id of the next request. | |
138 | * @notifications: A list of struct seccomp_knotif elements. | |
6a21cc50 TA |
139 | */ |
140 | struct notification { | |
141 | struct semaphore request; | |
142 | u64 next_id; | |
143 | struct list_head notifications; | |
6a21cc50 | 144 | }; |
e2cfabdf WD |
145 | |
146 | /** | |
147 | * struct seccomp_filter - container for seccomp BPF programs | |
148 | * | |
b707ddee CB |
149 | * @refs: Reference count to manage the object lifetime. |
150 | * A filter's reference count is incremented for each directly | |
151 | * attached task, once for the dependent filter, and if | |
152 | * requested for the user notifier. When @refs reaches zero, | |
153 | * the filter can be freed. | |
99cdb8b9 CB |
154 | * @users: A filter's @users count is incremented for each directly |
155 | * attached task (filter installation, fork(), thread_sync), | |
156 | * and once for the dependent filter (tracked in filter->prev). | |
157 | * When it reaches zero it indicates that no direct or indirect | |
158 | * users of that filter exist. No new tasks can get associated with | |
159 | * this filter after reaching 0. The @users count is always smaller | |
160 | * or equal to @refs. Hence, reaching 0 for @users does not mean | |
161 | * the filter can be freed. | |
e66a3997 | 162 | * @log: true if all actions except for SECCOMP_RET_ALLOW should be logged |
e2cfabdf | 163 | * @prev: points to a previously installed, or inherited, filter |
285fdfc5 | 164 | * @prog: the BPF program to evaluate |
6a21cc50 TA |
165 | * @notif: the struct that holds all notification related information |
166 | * @notify_lock: A lock for all notification-related accesses. | |
76194c4e | 167 | * @wqh: A wait queue for poll if a notifier is in use. |
e2cfabdf WD |
168 | * |
169 | * seccomp_filter objects are organized in a tree linked via the @prev | |
170 | * pointer. For any task, it appears to be a singly-linked list starting | |
171 | * with current->seccomp.filter, the most recently attached or inherited filter. | |
172 | * However, multiple filters may share a @prev node, by way of fork(), which | |
173 | * results in a unidirectional tree existing in memory. This is similar to | |
174 | * how namespaces work. | |
175 | * | |
176 | * seccomp_filter objects should never be modified after being attached | |
b707ddee | 177 | * to a task_struct (other than @refs). |
e2cfabdf WD |
178 | */ |
179 | struct seccomp_filter { | |
b707ddee | 180 | refcount_t refs; |
99cdb8b9 | 181 | refcount_t users; |
e66a3997 | 182 | bool log; |
e2cfabdf | 183 | struct seccomp_filter *prev; |
7ae457c1 | 184 | struct bpf_prog *prog; |
6a21cc50 TA |
185 | struct notification *notif; |
186 | struct mutex notify_lock; | |
76194c4e | 187 | wait_queue_head_t wqh; |
e2cfabdf WD |
188 | }; |
189 | ||
190 | /* Limit any path through the tree to 256KB worth of instructions. */ | |
191 | #define MAX_INSNS_PER_PATH ((1 << 18) / sizeof(struct sock_filter)) | |
192 | ||
bd4cf0ed | 193 | /* |
e2cfabdf WD |
194 | * Endianness is explicitly ignored and left for BPF program authors to manage |
195 | * as per the specific architecture. | |
196 | */ | |
bd4cf0ed | 197 | static void populate_seccomp_data(struct seccomp_data *sd) |
e2cfabdf | 198 | { |
bd4cf0ed AS |
199 | struct task_struct *task = current; |
200 | struct pt_regs *regs = task_pt_regs(task); | |
2eac7648 | 201 | unsigned long args[6]; |
e2cfabdf | 202 | |
bd4cf0ed | 203 | sd->nr = syscall_get_nr(task, regs); |
16add411 | 204 | sd->arch = syscall_get_arch(task); |
b35f549d | 205 | syscall_get_arguments(task, regs, args); |
2eac7648 DB |
206 | sd->args[0] = args[0]; |
207 | sd->args[1] = args[1]; | |
208 | sd->args[2] = args[2]; | |
209 | sd->args[3] = args[3]; | |
210 | sd->args[4] = args[4]; | |
211 | sd->args[5] = args[5]; | |
bd4cf0ed | 212 | sd->instruction_pointer = KSTK_EIP(task); |
e2cfabdf WD |
213 | } |
214 | ||
215 | /** | |
216 | * seccomp_check_filter - verify seccomp filter code | |
217 | * @filter: filter to verify | |
218 | * @flen: length of filter | |
219 | * | |
4df95ff4 | 220 | * Takes a previously checked filter (by bpf_check_classic) and |
e2cfabdf WD |
221 | * redirects all filter code that loads struct sk_buff data |
222 | * and related data through seccomp_bpf_load. It also | |
223 | * enforces length and alignment checking of those loads. | |
224 | * | |
225 | * Returns 0 if the rule set is legal or -EINVAL if not. | |
226 | */ | |
227 | static int seccomp_check_filter(struct sock_filter *filter, unsigned int flen) | |
228 | { | |
229 | int pc; | |
230 | for (pc = 0; pc < flen; pc++) { | |
231 | struct sock_filter *ftest = &filter[pc]; | |
232 | u16 code = ftest->code; | |
233 | u32 k = ftest->k; | |
234 | ||
235 | switch (code) { | |
34805931 | 236 | case BPF_LD | BPF_W | BPF_ABS: |
bd4cf0ed | 237 | ftest->code = BPF_LDX | BPF_W | BPF_ABS; |
e2cfabdf WD |
238 | /* 32-bit aligned and not out of bounds. */ |
239 | if (k >= sizeof(struct seccomp_data) || k & 3) | |
240 | return -EINVAL; | |
241 | continue; | |
34805931 | 242 | case BPF_LD | BPF_W | BPF_LEN: |
bd4cf0ed | 243 | ftest->code = BPF_LD | BPF_IMM; |
e2cfabdf WD |
244 | ftest->k = sizeof(struct seccomp_data); |
245 | continue; | |
34805931 | 246 | case BPF_LDX | BPF_W | BPF_LEN: |
bd4cf0ed | 247 | ftest->code = BPF_LDX | BPF_IMM; |
e2cfabdf WD |
248 | ftest->k = sizeof(struct seccomp_data); |
249 | continue; | |
250 | /* Explicitly include allowed calls. */ | |
34805931 DB |
251 | case BPF_RET | BPF_K: |
252 | case BPF_RET | BPF_A: | |
253 | case BPF_ALU | BPF_ADD | BPF_K: | |
254 | case BPF_ALU | BPF_ADD | BPF_X: | |
255 | case BPF_ALU | BPF_SUB | BPF_K: | |
256 | case BPF_ALU | BPF_SUB | BPF_X: | |
257 | case BPF_ALU | BPF_MUL | BPF_K: | |
258 | case BPF_ALU | BPF_MUL | BPF_X: | |
259 | case BPF_ALU | BPF_DIV | BPF_K: | |
260 | case BPF_ALU | BPF_DIV | BPF_X: | |
261 | case BPF_ALU | BPF_AND | BPF_K: | |
262 | case BPF_ALU | BPF_AND | BPF_X: | |
263 | case BPF_ALU | BPF_OR | BPF_K: | |
264 | case BPF_ALU | BPF_OR | BPF_X: | |
265 | case BPF_ALU | BPF_XOR | BPF_K: | |
266 | case BPF_ALU | BPF_XOR | BPF_X: | |
267 | case BPF_ALU | BPF_LSH | BPF_K: | |
268 | case BPF_ALU | BPF_LSH | BPF_X: | |
269 | case BPF_ALU | BPF_RSH | BPF_K: | |
270 | case BPF_ALU | BPF_RSH | BPF_X: | |
271 | case BPF_ALU | BPF_NEG: | |
272 | case BPF_LD | BPF_IMM: | |
273 | case BPF_LDX | BPF_IMM: | |
274 | case BPF_MISC | BPF_TAX: | |
275 | case BPF_MISC | BPF_TXA: | |
276 | case BPF_LD | BPF_MEM: | |
277 | case BPF_LDX | BPF_MEM: | |
278 | case BPF_ST: | |
279 | case BPF_STX: | |
280 | case BPF_JMP | BPF_JA: | |
281 | case BPF_JMP | BPF_JEQ | BPF_K: | |
282 | case BPF_JMP | BPF_JEQ | BPF_X: | |
283 | case BPF_JMP | BPF_JGE | BPF_K: | |
284 | case BPF_JMP | BPF_JGE | BPF_X: | |
285 | case BPF_JMP | BPF_JGT | BPF_K: | |
286 | case BPF_JMP | BPF_JGT | BPF_X: | |
287 | case BPF_JMP | BPF_JSET | BPF_K: | |
288 | case BPF_JMP | BPF_JSET | BPF_X: | |
e2cfabdf WD |
289 | continue; |
290 | default: | |
291 | return -EINVAL; | |
292 | } | |
293 | } | |
294 | return 0; | |
295 | } | |
296 | ||
297 | /** | |
285fdfc5 MS |
298 | * seccomp_run_filters - evaluates all seccomp filters against @sd |
299 | * @sd: optional seccomp data to be passed to filters | |
deb4de8b KC |
300 | * @match: stores struct seccomp_filter that resulted in the return value, |
301 | * unless filter returned SECCOMP_RET_ALLOW, in which case it will | |
302 | * be unchanged. | |
e2cfabdf WD |
303 | * |
304 | * Returns valid seccomp BPF response codes. | |
305 | */ | |
0466bdb9 | 306 | #define ACTION_ONLY(ret) ((s32)((ret) & (SECCOMP_RET_ACTION_FULL))) |
deb4de8b KC |
307 | static u32 seccomp_run_filters(const struct seccomp_data *sd, |
308 | struct seccomp_filter **match) | |
e2cfabdf | 309 | { |
acf3b2c7 | 310 | u32 ret = SECCOMP_RET_ALLOW; |
8225d385 PK |
311 | /* Make sure cross-thread synced filter points somewhere sane. */ |
312 | struct seccomp_filter *f = | |
506458ef | 313 | READ_ONCE(current->seccomp.filter); |
acf3b2c7 WD |
314 | |
315 | /* Ensure unexpected behavior doesn't result in failing open. */ | |
0d42d73a | 316 | if (WARN_ON(f == NULL)) |
4d3b0b05 | 317 | return SECCOMP_RET_KILL_PROCESS; |
acf3b2c7 | 318 | |
e2cfabdf WD |
319 | /* |
320 | * All filters in the list are evaluated and the lowest BPF return | |
acf3b2c7 | 321 | * value always takes priority (ignoring the DATA). |
e2cfabdf | 322 | */ |
3ba2530c | 323 | for (; f; f = f->prev) { |
3d9f773c | 324 | u32 cur_ret = bpf_prog_run_pin_on_cpu(f->prog, sd); |
8f577cad | 325 | |
0466bdb9 | 326 | if (ACTION_ONLY(cur_ret) < ACTION_ONLY(ret)) { |
acf3b2c7 | 327 | ret = cur_ret; |
deb4de8b KC |
328 | *match = f; |
329 | } | |
e2cfabdf WD |
330 | } |
331 | return ret; | |
332 | } | |
1f41b450 | 333 | #endif /* CONFIG_SECCOMP_FILTER */ |
e2cfabdf | 334 | |
1f41b450 KC |
335 | static inline bool seccomp_may_assign_mode(unsigned long seccomp_mode) |
336 | { | |
69f6a34b | 337 | assert_spin_locked(¤t->sighand->siglock); |
dbd95212 | 338 | |
1f41b450 KC |
339 | if (current->seccomp.mode && current->seccomp.mode != seccomp_mode) |
340 | return false; | |
341 | ||
342 | return true; | |
343 | } | |
344 | ||
8bf37d8c | 345 | void __weak arch_seccomp_spec_mitigate(struct task_struct *task) { } |
5c307089 | 346 | |
3ba2530c | 347 | static inline void seccomp_assign_mode(struct task_struct *task, |
00a02d0c KC |
348 | unsigned long seccomp_mode, |
349 | unsigned long flags) | |
1f41b450 | 350 | { |
69f6a34b | 351 | assert_spin_locked(&task->sighand->siglock); |
dbd95212 | 352 | |
3ba2530c KC |
353 | task->seccomp.mode = seccomp_mode; |
354 | /* | |
355 | * Make sure TIF_SECCOMP cannot be set before the mode (and | |
356 | * filter) is set. | |
357 | */ | |
358 | smp_mb__before_atomic(); | |
00a02d0c KC |
359 | /* Assume default seccomp processes want spec flaw mitigation. */ |
360 | if ((flags & SECCOMP_FILTER_FLAG_SPEC_ALLOW) == 0) | |
8bf37d8c | 361 | arch_seccomp_spec_mitigate(task); |
3ba2530c | 362 | set_tsk_thread_flag(task, TIF_SECCOMP); |
1f41b450 KC |
363 | } |
364 | ||
365 | #ifdef CONFIG_SECCOMP_FILTER | |
c2e1f2e3 KC |
366 | /* Returns 1 if the parent is an ancestor of the child. */ |
367 | static int is_ancestor(struct seccomp_filter *parent, | |
368 | struct seccomp_filter *child) | |
369 | { | |
370 | /* NULL is the root ancestor. */ | |
371 | if (parent == NULL) | |
372 | return 1; | |
373 | for (; child; child = child->prev) | |
374 | if (child == parent) | |
375 | return 1; | |
376 | return 0; | |
377 | } | |
378 | ||
379 | /** | |
380 | * seccomp_can_sync_threads: checks if all threads can be synchronized | |
381 | * | |
382 | * Expects sighand and cred_guard_mutex locks to be held. | |
383 | * | |
384 | * Returns 0 on success, -ve on error, or the pid of a thread which was | |
6beff00b | 385 | * either not in the correct seccomp mode or did not have an ancestral |
c2e1f2e3 KC |
386 | * seccomp filter. |
387 | */ | |
388 | static inline pid_t seccomp_can_sync_threads(void) | |
389 | { | |
390 | struct task_struct *thread, *caller; | |
391 | ||
392 | BUG_ON(!mutex_is_locked(¤t->signal->cred_guard_mutex)); | |
69f6a34b | 393 | assert_spin_locked(¤t->sighand->siglock); |
c2e1f2e3 KC |
394 | |
395 | /* Validate all threads being eligible for synchronization. */ | |
396 | caller = current; | |
397 | for_each_thread(caller, thread) { | |
398 | pid_t failed; | |
399 | ||
400 | /* Skip current, since it is initiating the sync. */ | |
401 | if (thread == caller) | |
402 | continue; | |
403 | ||
404 | if (thread->seccomp.mode == SECCOMP_MODE_DISABLED || | |
405 | (thread->seccomp.mode == SECCOMP_MODE_FILTER && | |
406 | is_ancestor(thread->seccomp.filter, | |
407 | caller->seccomp.filter))) | |
408 | continue; | |
409 | ||
410 | /* Return the first thread that cannot be synchronized. */ | |
411 | failed = task_pid_vnr(thread); | |
412 | /* If the pid cannot be resolved, then return -ESRCH */ | |
0d42d73a | 413 | if (WARN_ON(failed == 0)) |
c2e1f2e3 KC |
414 | failed = -ESRCH; |
415 | return failed; | |
416 | } | |
417 | ||
418 | return 0; | |
419 | } | |
420 | ||
3a15fb6e CB |
421 | static inline void seccomp_filter_free(struct seccomp_filter *filter) |
422 | { | |
423 | if (filter) { | |
424 | bpf_prog_destroy(filter->prog); | |
425 | kfree(filter); | |
426 | } | |
427 | } | |
428 | ||
99cdb8b9 CB |
429 | static void __seccomp_filter_orphan(struct seccomp_filter *orig) |
430 | { | |
431 | while (orig && refcount_dec_and_test(&orig->users)) { | |
432 | if (waitqueue_active(&orig->wqh)) | |
433 | wake_up_poll(&orig->wqh, EPOLLHUP); | |
434 | orig = orig->prev; | |
435 | } | |
436 | } | |
437 | ||
3a15fb6e CB |
438 | static void __put_seccomp_filter(struct seccomp_filter *orig) |
439 | { | |
440 | /* Clean up single-reference branches iteratively. */ | |
441 | while (orig && refcount_dec_and_test(&orig->refs)) { | |
442 | struct seccomp_filter *freeme = orig; | |
443 | orig = orig->prev; | |
444 | seccomp_filter_free(freeme); | |
445 | } | |
446 | } | |
447 | ||
99cdb8b9 CB |
448 | static void __seccomp_filter_release(struct seccomp_filter *orig) |
449 | { | |
450 | /* Notify about any unused filters in the task's former filter tree. */ | |
451 | __seccomp_filter_orphan(orig); | |
452 | /* Finally drop all references to the task's former tree. */ | |
453 | __put_seccomp_filter(orig); | |
454 | } | |
455 | ||
3a15fb6e | 456 | /** |
99cdb8b9 CB |
457 | * seccomp_filter_release - Detach the task from its filter tree, |
458 | * drop its reference count, and notify | |
459 | * about unused filters | |
3a15fb6e CB |
460 | * |
461 | * This function should only be called when the task is exiting as | |
462 | * it detaches it from its filter tree. As such, READ_ONCE() and | |
463 | * barriers are not needed here, as would normally be needed. | |
464 | */ | |
465 | void seccomp_filter_release(struct task_struct *tsk) | |
466 | { | |
467 | struct seccomp_filter *orig = tsk->seccomp.filter; | |
468 | ||
469 | /* Detach task from its filter tree. */ | |
470 | tsk->seccomp.filter = NULL; | |
99cdb8b9 | 471 | __seccomp_filter_release(orig); |
3a15fb6e CB |
472 | } |
473 | ||
c2e1f2e3 KC |
474 | /** |
475 | * seccomp_sync_threads: sets all threads to use current's filter | |
476 | * | |
477 | * Expects sighand and cred_guard_mutex locks to be held, and for | |
478 | * seccomp_can_sync_threads() to have returned success already | |
479 | * without dropping the locks. | |
480 | * | |
481 | */ | |
00a02d0c | 482 | static inline void seccomp_sync_threads(unsigned long flags) |
c2e1f2e3 KC |
483 | { |
484 | struct task_struct *thread, *caller; | |
485 | ||
486 | BUG_ON(!mutex_is_locked(¤t->signal->cred_guard_mutex)); | |
69f6a34b | 487 | assert_spin_locked(¤t->sighand->siglock); |
c2e1f2e3 KC |
488 | |
489 | /* Synchronize all threads. */ | |
490 | caller = current; | |
491 | for_each_thread(caller, thread) { | |
492 | /* Skip current, since it needs no changes. */ | |
493 | if (thread == caller) | |
494 | continue; | |
495 | ||
496 | /* Get a task reference for the new leaf node. */ | |
497 | get_seccomp_filter(caller); | |
99cdb8b9 | 498 | |
c2e1f2e3 KC |
499 | /* |
500 | * Drop the task reference to the shared ancestor since | |
501 | * current's path will hold a reference. (This also | |
502 | * allows a put before the assignment.) | |
503 | */ | |
99cdb8b9 CB |
504 | __seccomp_filter_release(thread->seccomp.filter); |
505 | ||
506 | /* Make our new filter tree visible. */ | |
c2e1f2e3 KC |
507 | smp_store_release(&thread->seccomp.filter, |
508 | caller->seccomp.filter); | |
c818c03b KC |
509 | atomic_set(&thread->seccomp.filter_count, |
510 | atomic_read(&thread->seccomp.filter_count)); | |
103502a3 JH |
511 | |
512 | /* | |
513 | * Don't let an unprivileged task work around | |
514 | * the no_new_privs restriction by creating | |
515 | * a thread that sets it up, enters seccomp, | |
516 | * then dies. | |
517 | */ | |
518 | if (task_no_new_privs(caller)) | |
519 | task_set_no_new_privs(thread); | |
520 | ||
c2e1f2e3 KC |
521 | /* |
522 | * Opt the other thread into seccomp if needed. | |
523 | * As threads are considered to be trust-realm | |
524 | * equivalent (see ptrace_may_access), it is safe to | |
525 | * allow one thread to transition the other. | |
526 | */ | |
103502a3 | 527 | if (thread->seccomp.mode == SECCOMP_MODE_DISABLED) |
00a02d0c KC |
528 | seccomp_assign_mode(thread, SECCOMP_MODE_FILTER, |
529 | flags); | |
c2e1f2e3 KC |
530 | } |
531 | } | |
532 | ||
e2cfabdf | 533 | /** |
c8bee430 | 534 | * seccomp_prepare_filter: Prepares a seccomp filter for use. |
e2cfabdf WD |
535 | * @fprog: BPF program to install |
536 | * | |
c8bee430 | 537 | * Returns filter on success or an ERR_PTR on failure. |
e2cfabdf | 538 | */ |
c8bee430 | 539 | static struct seccomp_filter *seccomp_prepare_filter(struct sock_fprog *fprog) |
e2cfabdf | 540 | { |
ac67eb2c DB |
541 | struct seccomp_filter *sfilter; |
542 | int ret; | |
97f2645f | 543 | const bool save_orig = IS_ENABLED(CONFIG_CHECKPOINT_RESTORE); |
e2cfabdf WD |
544 | |
545 | if (fprog->len == 0 || fprog->len > BPF_MAXINSNS) | |
c8bee430 | 546 | return ERR_PTR(-EINVAL); |
d9e12f42 | 547 | |
c8bee430 | 548 | BUG_ON(INT_MAX / fprog->len < sizeof(struct sock_filter)); |
e2cfabdf WD |
549 | |
550 | /* | |
119ce5c8 | 551 | * Installing a seccomp filter requires that the task has |
e2cfabdf WD |
552 | * CAP_SYS_ADMIN in its namespace or be running with no_new_privs. |
553 | * This avoids scenarios where unprivileged tasks can affect the | |
554 | * behavior of privileged children. | |
555 | */ | |
1d4457f9 | 556 | if (!task_no_new_privs(current) && |
c1a85a00 MM |
557 | security_capable(current_cred(), current_user_ns(), |
558 | CAP_SYS_ADMIN, CAP_OPT_NOAUDIT) != 0) | |
c8bee430 | 559 | return ERR_PTR(-EACCES); |
e2cfabdf | 560 | |
bd4cf0ed | 561 | /* Allocate a new seccomp_filter */ |
ac67eb2c DB |
562 | sfilter = kzalloc(sizeof(*sfilter), GFP_KERNEL | __GFP_NOWARN); |
563 | if (!sfilter) | |
d9e12f42 | 564 | return ERR_PTR(-ENOMEM); |
ac67eb2c | 565 | |
6a21cc50 | 566 | mutex_init(&sfilter->notify_lock); |
ac67eb2c | 567 | ret = bpf_prog_create_from_user(&sfilter->prog, fprog, |
f8e529ed | 568 | seccomp_check_filter, save_orig); |
ac67eb2c DB |
569 | if (ret < 0) { |
570 | kfree(sfilter); | |
571 | return ERR_PTR(ret); | |
d9e12f42 | 572 | } |
bd4cf0ed | 573 | |
b707ddee | 574 | refcount_set(&sfilter->refs, 1); |
99cdb8b9 | 575 | refcount_set(&sfilter->users, 1); |
76194c4e | 576 | init_waitqueue_head(&sfilter->wqh); |
e2cfabdf | 577 | |
ac67eb2c | 578 | return sfilter; |
e2cfabdf WD |
579 | } |
580 | ||
581 | /** | |
c8bee430 | 582 | * seccomp_prepare_user_filter - prepares a user-supplied sock_fprog |
e2cfabdf WD |
583 | * @user_filter: pointer to the user data containing a sock_fprog. |
584 | * | |
585 | * Returns 0 on success and non-zero otherwise. | |
586 | */ | |
c8bee430 KC |
587 | static struct seccomp_filter * |
588 | seccomp_prepare_user_filter(const char __user *user_filter) | |
e2cfabdf WD |
589 | { |
590 | struct sock_fprog fprog; | |
c8bee430 | 591 | struct seccomp_filter *filter = ERR_PTR(-EFAULT); |
e2cfabdf WD |
592 | |
593 | #ifdef CONFIG_COMPAT | |
5c38065e | 594 | if (in_compat_syscall()) { |
e2cfabdf WD |
595 | struct compat_sock_fprog fprog32; |
596 | if (copy_from_user(&fprog32, user_filter, sizeof(fprog32))) | |
597 | goto out; | |
598 | fprog.len = fprog32.len; | |
599 | fprog.filter = compat_ptr(fprog32.filter); | |
600 | } else /* falls through to the if below. */ | |
601 | #endif | |
602 | if (copy_from_user(&fprog, user_filter, sizeof(fprog))) | |
603 | goto out; | |
c8bee430 | 604 | filter = seccomp_prepare_filter(&fprog); |
e2cfabdf | 605 | out: |
c8bee430 KC |
606 | return filter; |
607 | } | |
608 | ||
609 | /** | |
610 | * seccomp_attach_filter: validate and attach filter | |
611 | * @flags: flags to change filter behavior | |
612 | * @filter: seccomp filter to add to the current process | |
613 | * | |
dbd95212 KC |
614 | * Caller must be holding current->sighand->siglock lock. |
615 | * | |
7a0df7fb TA |
616 | * Returns 0 on success, -ve on error, or |
617 | * - in TSYNC mode: the pid of a thread which was either not in the correct | |
618 | * seccomp mode or did not have an ancestral seccomp filter | |
619 | * - in NEW_LISTENER mode: the fd of the new listener | |
c8bee430 KC |
620 | */ |
621 | static long seccomp_attach_filter(unsigned int flags, | |
622 | struct seccomp_filter *filter) | |
623 | { | |
624 | unsigned long total_insns; | |
625 | struct seccomp_filter *walker; | |
626 | ||
69f6a34b | 627 | assert_spin_locked(¤t->sighand->siglock); |
dbd95212 | 628 | |
c8bee430 KC |
629 | /* Validate resulting filter length. */ |
630 | total_insns = filter->prog->len; | |
631 | for (walker = current->seccomp.filter; walker; walker = walker->prev) | |
632 | total_insns += walker->prog->len + 4; /* 4 instr penalty */ | |
633 | if (total_insns > MAX_INSNS_PER_PATH) | |
634 | return -ENOMEM; | |
635 | ||
c2e1f2e3 KC |
636 | /* If thread sync has been requested, check that it is possible. */ |
637 | if (flags & SECCOMP_FILTER_FLAG_TSYNC) { | |
638 | int ret; | |
639 | ||
640 | ret = seccomp_can_sync_threads(); | |
51891498 TA |
641 | if (ret) { |
642 | if (flags & SECCOMP_FILTER_FLAG_TSYNC_ESRCH) | |
643 | return -ESRCH; | |
644 | else | |
645 | return ret; | |
646 | } | |
c2e1f2e3 KC |
647 | } |
648 | ||
e66a3997 TH |
649 | /* Set log flag, if present. */ |
650 | if (flags & SECCOMP_FILTER_FLAG_LOG) | |
651 | filter->log = true; | |
652 | ||
c8bee430 KC |
653 | /* |
654 | * If there is an existing filter, make it the prev and don't drop its | |
655 | * task reference. | |
656 | */ | |
657 | filter->prev = current->seccomp.filter; | |
658 | current->seccomp.filter = filter; | |
c818c03b | 659 | atomic_inc(¤t->seccomp.filter_count); |
c8bee430 | 660 | |
c2e1f2e3 KC |
661 | /* Now that the new filter is in place, synchronize to all threads. */ |
662 | if (flags & SECCOMP_FILTER_FLAG_TSYNC) | |
00a02d0c | 663 | seccomp_sync_threads(flags); |
c2e1f2e3 | 664 | |
c8bee430 | 665 | return 0; |
e2cfabdf WD |
666 | } |
667 | ||
084f5601 | 668 | static void __get_seccomp_filter(struct seccomp_filter *filter) |
66a733ea | 669 | { |
b707ddee | 670 | refcount_inc(&filter->refs); |
66a733ea ON |
671 | } |
672 | ||
e2cfabdf WD |
673 | /* get_seccomp_filter - increments the reference count of the filter on @tsk */ |
674 | void get_seccomp_filter(struct task_struct *tsk) | |
675 | { | |
676 | struct seccomp_filter *orig = tsk->seccomp.filter; | |
677 | if (!orig) | |
678 | return; | |
66a733ea | 679 | __get_seccomp_filter(orig); |
99cdb8b9 | 680 | refcount_inc(&orig->users); |
e2cfabdf WD |
681 | } |
682 | ||
ae7795bc | 683 | static void seccomp_init_siginfo(kernel_siginfo_t *info, int syscall, int reason) |
b25e6716 | 684 | { |
3b10db2b | 685 | clear_siginfo(info); |
b25e6716 MF |
686 | info->si_signo = SIGSYS; |
687 | info->si_code = SYS_SECCOMP; | |
688 | info->si_call_addr = (void __user *)KSTK_EIP(current); | |
689 | info->si_errno = reason; | |
16add411 | 690 | info->si_arch = syscall_get_arch(current); |
b25e6716 MF |
691 | info->si_syscall = syscall; |
692 | } | |
693 | ||
bb6ea430 WD |
694 | /** |
695 | * seccomp_send_sigsys - signals the task to allow in-process syscall emulation | |
696 | * @syscall: syscall number to send to userland | |
697 | * @reason: filter-supplied reason code to send to userland (via si_errno) | |
698 | * | |
699 | * Forces a SIGSYS with a code of SYS_SECCOMP and related sigsys info. | |
700 | */ | |
701 | static void seccomp_send_sigsys(int syscall, int reason) | |
702 | { | |
ae7795bc | 703 | struct kernel_siginfo info; |
b25e6716 | 704 | seccomp_init_siginfo(&info, syscall, reason); |
a89e9b8a | 705 | force_sig_info(&info); |
bb6ea430 | 706 | } |
e2cfabdf | 707 | #endif /* CONFIG_SECCOMP_FILTER */ |
1da177e4 | 708 | |
0ddec0fc | 709 | /* For use with seccomp_actions_logged */ |
4d3b0b05 KC |
710 | #define SECCOMP_LOG_KILL_PROCESS (1 << 0) |
711 | #define SECCOMP_LOG_KILL_THREAD (1 << 1) | |
0ddec0fc TH |
712 | #define SECCOMP_LOG_TRAP (1 << 2) |
713 | #define SECCOMP_LOG_ERRNO (1 << 3) | |
714 | #define SECCOMP_LOG_TRACE (1 << 4) | |
59f5cf44 TH |
715 | #define SECCOMP_LOG_LOG (1 << 5) |
716 | #define SECCOMP_LOG_ALLOW (1 << 6) | |
6a21cc50 | 717 | #define SECCOMP_LOG_USER_NOTIF (1 << 7) |
0ddec0fc | 718 | |
4d3b0b05 KC |
719 | static u32 seccomp_actions_logged = SECCOMP_LOG_KILL_PROCESS | |
720 | SECCOMP_LOG_KILL_THREAD | | |
fd76875c KC |
721 | SECCOMP_LOG_TRAP | |
722 | SECCOMP_LOG_ERRNO | | |
6a21cc50 | 723 | SECCOMP_LOG_USER_NOTIF | |
fd76875c | 724 | SECCOMP_LOG_TRACE | |
59f5cf44 | 725 | SECCOMP_LOG_LOG; |
0ddec0fc | 726 | |
e66a3997 TH |
727 | static inline void seccomp_log(unsigned long syscall, long signr, u32 action, |
728 | bool requested) | |
0ddec0fc TH |
729 | { |
730 | bool log = false; | |
731 | ||
732 | switch (action) { | |
733 | case SECCOMP_RET_ALLOW: | |
e66a3997 | 734 | break; |
0ddec0fc | 735 | case SECCOMP_RET_TRAP: |
e66a3997 TH |
736 | log = requested && seccomp_actions_logged & SECCOMP_LOG_TRAP; |
737 | break; | |
0ddec0fc | 738 | case SECCOMP_RET_ERRNO: |
e66a3997 TH |
739 | log = requested && seccomp_actions_logged & SECCOMP_LOG_ERRNO; |
740 | break; | |
0ddec0fc | 741 | case SECCOMP_RET_TRACE: |
e66a3997 | 742 | log = requested && seccomp_actions_logged & SECCOMP_LOG_TRACE; |
0ddec0fc | 743 | break; |
6a21cc50 TA |
744 | case SECCOMP_RET_USER_NOTIF: |
745 | log = requested && seccomp_actions_logged & SECCOMP_LOG_USER_NOTIF; | |
746 | break; | |
59f5cf44 TH |
747 | case SECCOMP_RET_LOG: |
748 | log = seccomp_actions_logged & SECCOMP_LOG_LOG; | |
749 | break; | |
fd76875c | 750 | case SECCOMP_RET_KILL_THREAD: |
fd76875c | 751 | log = seccomp_actions_logged & SECCOMP_LOG_KILL_THREAD; |
4d3b0b05 KC |
752 | break; |
753 | case SECCOMP_RET_KILL_PROCESS: | |
754 | default: | |
755 | log = seccomp_actions_logged & SECCOMP_LOG_KILL_PROCESS; | |
0ddec0fc TH |
756 | } |
757 | ||
758 | /* | |
326bee02 TH |
759 | * Emit an audit message when the action is RET_KILL_*, RET_LOG, or the |
760 | * FILTER_FLAG_LOG bit was set. The admin has the ability to silence | |
761 | * any action from being logged by removing the action name from the | |
762 | * seccomp_actions_logged sysctl. | |
0ddec0fc | 763 | */ |
326bee02 TH |
764 | if (!log) |
765 | return; | |
0ddec0fc | 766 | |
326bee02 | 767 | audit_seccomp(syscall, signr, action); |
0ddec0fc TH |
768 | } |
769 | ||
1da177e4 LT |
770 | /* |
771 | * Secure computing mode 1 allows only read/write/exit/sigreturn. | |
772 | * To be fully secure this must be combined with rlimit | |
773 | * to limit the stack allocations too. | |
774 | */ | |
cb4253aa | 775 | static const int mode1_syscalls[] = { |
1da177e4 | 776 | __NR_seccomp_read, __NR_seccomp_write, __NR_seccomp_exit, __NR_seccomp_sigreturn, |
fe4bfff8 | 777 | -1, /* negative terminated */ |
1da177e4 LT |
778 | }; |
779 | ||
a4412fc9 | 780 | static void __secure_computing_strict(int this_syscall) |
1da177e4 | 781 | { |
fe4bfff8 | 782 | const int *allowed_syscalls = mode1_syscalls; |
a4412fc9 | 783 | #ifdef CONFIG_COMPAT |
5c38065e | 784 | if (in_compat_syscall()) |
fe4bfff8 | 785 | allowed_syscalls = get_compat_mode1_syscalls(); |
a4412fc9 AL |
786 | #endif |
787 | do { | |
fe4bfff8 | 788 | if (*allowed_syscalls == this_syscall) |
a4412fc9 | 789 | return; |
fe4bfff8 | 790 | } while (*++allowed_syscalls != -1); |
a4412fc9 AL |
791 | |
792 | #ifdef SECCOMP_DEBUG | |
793 | dump_stack(); | |
794 | #endif | |
fd76875c | 795 | seccomp_log(this_syscall, SIGKILL, SECCOMP_RET_KILL_THREAD, true); |
a4412fc9 AL |
796 | do_exit(SIGKILL); |
797 | } | |
798 | ||
799 | #ifndef CONFIG_HAVE_ARCH_SECCOMP_FILTER | |
800 | void secure_computing_strict(int this_syscall) | |
801 | { | |
802 | int mode = current->seccomp.mode; | |
803 | ||
97f2645f | 804 | if (IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) && |
13c4a901 TA |
805 | unlikely(current->ptrace & PT_SUSPEND_SECCOMP)) |
806 | return; | |
807 | ||
221272f9 | 808 | if (mode == SECCOMP_MODE_DISABLED) |
a4412fc9 AL |
809 | return; |
810 | else if (mode == SECCOMP_MODE_STRICT) | |
811 | __secure_computing_strict(this_syscall); | |
812 | else | |
813 | BUG(); | |
814 | } | |
815 | #else | |
13aa72f0 AL |
816 | |
817 | #ifdef CONFIG_SECCOMP_FILTER | |
6a21cc50 TA |
818 | static u64 seccomp_next_notify_id(struct seccomp_filter *filter) |
819 | { | |
820 | /* | |
821 | * Note: overflow is ok here, the id just needs to be unique per | |
822 | * filter. | |
823 | */ | |
824 | lockdep_assert_held(&filter->notify_lock); | |
825 | return filter->notif->next_id++; | |
826 | } | |
827 | ||
7cf97b12 SD |
828 | static void seccomp_handle_addfd(struct seccomp_kaddfd *addfd) |
829 | { | |
830 | /* | |
831 | * Remove the notification, and reset the list pointers, indicating | |
832 | * that it has been handled. | |
833 | */ | |
834 | list_del_init(&addfd->list); | |
835 | addfd->ret = receive_fd_replace(addfd->fd, addfd->file, addfd->flags); | |
836 | complete(&addfd->completion); | |
837 | } | |
838 | ||
fb3c5386 CB |
839 | static int seccomp_do_user_notification(int this_syscall, |
840 | struct seccomp_filter *match, | |
841 | const struct seccomp_data *sd) | |
6a21cc50 TA |
842 | { |
843 | int err; | |
fb3c5386 | 844 | u32 flags = 0; |
6a21cc50 TA |
845 | long ret = 0; |
846 | struct seccomp_knotif n = {}; | |
7cf97b12 | 847 | struct seccomp_kaddfd *addfd, *tmp; |
6a21cc50 TA |
848 | |
849 | mutex_lock(&match->notify_lock); | |
850 | err = -ENOSYS; | |
851 | if (!match->notif) | |
852 | goto out; | |
853 | ||
854 | n.task = current; | |
855 | n.state = SECCOMP_NOTIFY_INIT; | |
856 | n.data = sd; | |
857 | n.id = seccomp_next_notify_id(match); | |
858 | init_completion(&n.ready); | |
859 | list_add(&n.list, &match->notif->notifications); | |
7cf97b12 | 860 | INIT_LIST_HEAD(&n.addfd); |
6a21cc50 TA |
861 | |
862 | up(&match->notif->request); | |
76194c4e | 863 | wake_up_poll(&match->wqh, EPOLLIN | EPOLLRDNORM); |
6a21cc50 TA |
864 | mutex_unlock(&match->notify_lock); |
865 | ||
866 | /* | |
867 | * This is where we wait for a reply from userspace. | |
868 | */ | |
7cf97b12 | 869 | wait: |
6a21cc50 TA |
870 | err = wait_for_completion_interruptible(&n.ready); |
871 | mutex_lock(&match->notify_lock); | |
872 | if (err == 0) { | |
7cf97b12 SD |
873 | /* Check if we were woken up by a addfd message */ |
874 | addfd = list_first_entry_or_null(&n.addfd, | |
875 | struct seccomp_kaddfd, list); | |
876 | if (addfd && n.state != SECCOMP_NOTIFY_REPLIED) { | |
877 | seccomp_handle_addfd(addfd); | |
878 | mutex_unlock(&match->notify_lock); | |
879 | goto wait; | |
880 | } | |
6a21cc50 TA |
881 | ret = n.val; |
882 | err = n.error; | |
fb3c5386 | 883 | flags = n.flags; |
6a21cc50 TA |
884 | } |
885 | ||
7cf97b12 SD |
886 | /* If there were any pending addfd calls, clear them out */ |
887 | list_for_each_entry_safe(addfd, tmp, &n.addfd, list) { | |
888 | /* The process went away before we got a chance to handle it */ | |
889 | addfd->ret = -ESRCH; | |
890 | list_del_init(&addfd->list); | |
891 | complete(&addfd->completion); | |
892 | } | |
893 | ||
6a21cc50 TA |
894 | /* |
895 | * Note that it's possible the listener died in between the time when | |
7cf97b12 | 896 | * we were notified of a response (or a signal) and when we were able to |
6a21cc50 TA |
897 | * re-acquire the lock, so only delete from the list if the |
898 | * notification actually exists. | |
899 | * | |
900 | * Also note that this test is only valid because there's no way to | |
901 | * *reattach* to a notifier right now. If one is added, we'll need to | |
902 | * keep track of the notif itself and make sure they match here. | |
903 | */ | |
904 | if (match->notif) | |
905 | list_del(&n.list); | |
906 | out: | |
907 | mutex_unlock(&match->notify_lock); | |
fb3c5386 CB |
908 | |
909 | /* Userspace requests to continue the syscall. */ | |
910 | if (flags & SECCOMP_USER_NOTIF_FLAG_CONTINUE) | |
911 | return 0; | |
912 | ||
6a21cc50 TA |
913 | syscall_set_return_value(current, task_pt_regs(current), |
914 | err, ret); | |
fb3c5386 | 915 | return -1; |
6a21cc50 TA |
916 | } |
917 | ||
ce6526e8 KC |
918 | static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd, |
919 | const bool recheck_after_trace) | |
13aa72f0 AL |
920 | { |
921 | u32 filter_ret, action; | |
deb4de8b | 922 | struct seccomp_filter *match = NULL; |
13aa72f0 | 923 | int data; |
db511391 | 924 | struct seccomp_data sd_local; |
1da177e4 | 925 | |
3ba2530c KC |
926 | /* |
927 | * Make sure that any changes to mode from another thread have | |
928 | * been seen after TIF_SECCOMP was seen. | |
929 | */ | |
930 | rmb(); | |
931 | ||
db511391 TA |
932 | if (!sd) { |
933 | populate_seccomp_data(&sd_local); | |
934 | sd = &sd_local; | |
935 | } | |
936 | ||
deb4de8b | 937 | filter_ret = seccomp_run_filters(sd, &match); |
13aa72f0 | 938 | data = filter_ret & SECCOMP_RET_DATA; |
0466bdb9 | 939 | action = filter_ret & SECCOMP_RET_ACTION_FULL; |
13aa72f0 AL |
940 | |
941 | switch (action) { | |
942 | case SECCOMP_RET_ERRNO: | |
580c57f1 KC |
943 | /* Set low-order bits as an errno, capped at MAX_ERRNO. */ |
944 | if (data > MAX_ERRNO) | |
945 | data = MAX_ERRNO; | |
d39bd00d | 946 | syscall_set_return_value(current, task_pt_regs(current), |
13aa72f0 AL |
947 | -data, 0); |
948 | goto skip; | |
949 | ||
950 | case SECCOMP_RET_TRAP: | |
951 | /* Show the handler the original registers. */ | |
d39bd00d | 952 | syscall_rollback(current, task_pt_regs(current)); |
13aa72f0 AL |
953 | /* Let the filter pass back 16 bits of data. */ |
954 | seccomp_send_sigsys(this_syscall, data); | |
955 | goto skip; | |
956 | ||
957 | case SECCOMP_RET_TRACE: | |
ce6526e8 KC |
958 | /* We've been put in this state by the ptracer already. */ |
959 | if (recheck_after_trace) | |
960 | return 0; | |
961 | ||
8112c4f1 KC |
962 | /* ENOSYS these calls if there is no tracer attached. */ |
963 | if (!ptrace_event_enabled(current, PTRACE_EVENT_SECCOMP)) { | |
964 | syscall_set_return_value(current, | |
965 | task_pt_regs(current), | |
966 | -ENOSYS, 0); | |
967 | goto skip; | |
968 | } | |
969 | ||
970 | /* Allow the BPF to provide the event message */ | |
971 | ptrace_event(PTRACE_EVENT_SECCOMP, data); | |
972 | /* | |
973 | * The delivery of a fatal signal during event | |
485a252a KC |
974 | * notification may silently skip tracer notification, |
975 | * which could leave us with a potentially unmodified | |
976 | * syscall that the tracer would have liked to have | |
977 | * changed. Since the process is about to die, we just | |
978 | * force the syscall to be skipped and let the signal | |
979 | * kill the process and correctly handle any tracer exit | |
980 | * notifications. | |
8112c4f1 KC |
981 | */ |
982 | if (fatal_signal_pending(current)) | |
485a252a | 983 | goto skip; |
8112c4f1 KC |
984 | /* Check if the tracer forced the syscall to be skipped. */ |
985 | this_syscall = syscall_get_nr(current, task_pt_regs(current)); | |
986 | if (this_syscall < 0) | |
987 | goto skip; | |
988 | ||
ce6526e8 KC |
989 | /* |
990 | * Recheck the syscall, since it may have changed. This | |
991 | * intentionally uses a NULL struct seccomp_data to force | |
992 | * a reload of all registers. This does not goto skip since | |
993 | * a skip would have already been reported. | |
994 | */ | |
995 | if (__seccomp_filter(this_syscall, NULL, true)) | |
996 | return -1; | |
997 | ||
8112c4f1 | 998 | return 0; |
13aa72f0 | 999 | |
6a21cc50 | 1000 | case SECCOMP_RET_USER_NOTIF: |
fb3c5386 CB |
1001 | if (seccomp_do_user_notification(this_syscall, match, sd)) |
1002 | goto skip; | |
1003 | ||
1004 | return 0; | |
6a21cc50 | 1005 | |
59f5cf44 TH |
1006 | case SECCOMP_RET_LOG: |
1007 | seccomp_log(this_syscall, 0, action, true); | |
1008 | return 0; | |
1009 | ||
13aa72f0 | 1010 | case SECCOMP_RET_ALLOW: |
deb4de8b KC |
1011 | /* |
1012 | * Note that the "match" filter will always be NULL for | |
1013 | * this action since SECCOMP_RET_ALLOW is the starting | |
1014 | * state in seccomp_run_filters(). | |
1015 | */ | |
8112c4f1 | 1016 | return 0; |
13aa72f0 | 1017 | |
fd76875c | 1018 | case SECCOMP_RET_KILL_THREAD: |
4d3b0b05 | 1019 | case SECCOMP_RET_KILL_PROCESS: |
131b6351 | 1020 | default: |
e66a3997 | 1021 | seccomp_log(this_syscall, SIGSYS, action, true); |
d7276e32 | 1022 | /* Dump core only if this is the last remaining thread. */ |
4d3b0b05 KC |
1023 | if (action == SECCOMP_RET_KILL_PROCESS || |
1024 | get_nr_threads(current) == 1) { | |
ae7795bc | 1025 | kernel_siginfo_t info; |
131b6351 | 1026 | |
d7276e32 KC |
1027 | /* Show the original registers in the dump. */ |
1028 | syscall_rollback(current, task_pt_regs(current)); | |
1029 | /* Trigger a manual coredump since do_exit skips it. */ | |
1030 | seccomp_init_siginfo(&info, this_syscall, data); | |
1031 | do_coredump(&info); | |
1032 | } | |
4d3b0b05 KC |
1033 | if (action == SECCOMP_RET_KILL_PROCESS) |
1034 | do_group_exit(SIGSYS); | |
1035 | else | |
1036 | do_exit(SIGSYS); | |
13aa72f0 AL |
1037 | } |
1038 | ||
1039 | unreachable(); | |
1040 | ||
1041 | skip: | |
e66a3997 | 1042 | seccomp_log(this_syscall, 0, action, match ? match->log : false); |
8112c4f1 KC |
1043 | return -1; |
1044 | } | |
1045 | #else | |
ce6526e8 KC |
1046 | static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd, |
1047 | const bool recheck_after_trace) | |
8112c4f1 KC |
1048 | { |
1049 | BUG(); | |
13aa72f0 | 1050 | } |
1da177e4 | 1051 | #endif |
13aa72f0 | 1052 | |
8112c4f1 | 1053 | int __secure_computing(const struct seccomp_data *sd) |
13aa72f0 AL |
1054 | { |
1055 | int mode = current->seccomp.mode; | |
8112c4f1 | 1056 | int this_syscall; |
13aa72f0 | 1057 | |
97f2645f | 1058 | if (IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) && |
13c4a901 | 1059 | unlikely(current->ptrace & PT_SUSPEND_SECCOMP)) |
8112c4f1 KC |
1060 | return 0; |
1061 | ||
1062 | this_syscall = sd ? sd->nr : | |
1063 | syscall_get_nr(current, task_pt_regs(current)); | |
13c4a901 | 1064 | |
13aa72f0 | 1065 | switch (mode) { |
e2cfabdf | 1066 | case SECCOMP_MODE_STRICT: |
13aa72f0 | 1067 | __secure_computing_strict(this_syscall); /* may call do_exit */ |
8112c4f1 | 1068 | return 0; |
13aa72f0 | 1069 | case SECCOMP_MODE_FILTER: |
ce6526e8 | 1070 | return __seccomp_filter(this_syscall, sd, false); |
1da177e4 LT |
1071 | default: |
1072 | BUG(); | |
1073 | } | |
13aa72f0 | 1074 | } |
a4412fc9 | 1075 | #endif /* CONFIG_HAVE_ARCH_SECCOMP_FILTER */ |
1d9d02fe AA |
1076 | |
1077 | long prctl_get_seccomp(void) | |
1078 | { | |
1079 | return current->seccomp.mode; | |
1080 | } | |
1081 | ||
e2cfabdf | 1082 | /** |
3b23dd12 | 1083 | * seccomp_set_mode_strict: internal function for setting strict seccomp |
e2cfabdf WD |
1084 | * |
1085 | * Once current->seccomp.mode is non-zero, it may not be changed. | |
1086 | * | |
1087 | * Returns 0 on success or -EINVAL on failure. | |
1088 | */ | |
3b23dd12 | 1089 | static long seccomp_set_mode_strict(void) |
1d9d02fe | 1090 | { |
3b23dd12 | 1091 | const unsigned long seccomp_mode = SECCOMP_MODE_STRICT; |
e2cfabdf | 1092 | long ret = -EINVAL; |
1d9d02fe | 1093 | |
dbd95212 KC |
1094 | spin_lock_irq(¤t->sighand->siglock); |
1095 | ||
1f41b450 | 1096 | if (!seccomp_may_assign_mode(seccomp_mode)) |
1d9d02fe AA |
1097 | goto out; |
1098 | ||
cf99abac | 1099 | #ifdef TIF_NOTSC |
3b23dd12 | 1100 | disable_TSC(); |
cf99abac | 1101 | #endif |
00a02d0c | 1102 | seccomp_assign_mode(current, seccomp_mode, 0); |
3b23dd12 KC |
1103 | ret = 0; |
1104 | ||
1105 | out: | |
dbd95212 | 1106 | spin_unlock_irq(¤t->sighand->siglock); |
3b23dd12 KC |
1107 | |
1108 | return ret; | |
1109 | } | |
1110 | ||
e2cfabdf | 1111 | #ifdef CONFIG_SECCOMP_FILTER |
e8393179 TA |
1112 | static void seccomp_notify_free(struct seccomp_filter *filter) |
1113 | { | |
1114 | kfree(filter->notif); | |
1115 | filter->notif = NULL; | |
1116 | } | |
1117 | ||
a566a901 | 1118 | static void seccomp_notify_detach(struct seccomp_filter *filter) |
6a21cc50 | 1119 | { |
6a21cc50 TA |
1120 | struct seccomp_knotif *knotif; |
1121 | ||
a811dc61 | 1122 | if (!filter) |
a566a901 | 1123 | return; |
a811dc61 | 1124 | |
6a21cc50 TA |
1125 | mutex_lock(&filter->notify_lock); |
1126 | ||
1127 | /* | |
1128 | * If this file is being closed because e.g. the task who owned it | |
1129 | * died, let's wake everyone up who was waiting on us. | |
1130 | */ | |
1131 | list_for_each_entry(knotif, &filter->notif->notifications, list) { | |
1132 | if (knotif->state == SECCOMP_NOTIFY_REPLIED) | |
1133 | continue; | |
1134 | ||
1135 | knotif->state = SECCOMP_NOTIFY_REPLIED; | |
1136 | knotif->error = -ENOSYS; | |
1137 | knotif->val = 0; | |
1138 | ||
7cf97b12 SD |
1139 | /* |
1140 | * We do not need to wake up any pending addfd messages, as | |
1141 | * the notifier will do that for us, as this just looks | |
1142 | * like a standard reply. | |
1143 | */ | |
6a21cc50 TA |
1144 | complete(&knotif->ready); |
1145 | } | |
1146 | ||
e8393179 | 1147 | seccomp_notify_free(filter); |
6a21cc50 | 1148 | mutex_unlock(&filter->notify_lock); |
a566a901 TA |
1149 | } |
1150 | ||
1151 | static int seccomp_notify_release(struct inode *inode, struct file *file) | |
1152 | { | |
1153 | struct seccomp_filter *filter = file->private_data; | |
1154 | ||
1155 | seccomp_notify_detach(filter); | |
6a21cc50 TA |
1156 | __put_seccomp_filter(filter); |
1157 | return 0; | |
1158 | } | |
1159 | ||
9f87dcf1 SD |
1160 | /* must be called with notif_lock held */ |
1161 | static inline struct seccomp_knotif * | |
1162 | find_notification(struct seccomp_filter *filter, u64 id) | |
1163 | { | |
1164 | struct seccomp_knotif *cur; | |
1165 | ||
1166 | lockdep_assert_held(&filter->notify_lock); | |
1167 | ||
1168 | list_for_each_entry(cur, &filter->notif->notifications, list) { | |
1169 | if (cur->id == id) | |
1170 | return cur; | |
1171 | } | |
1172 | ||
1173 | return NULL; | |
1174 | } | |
1175 | ||
1176 | ||
6a21cc50 TA |
1177 | static long seccomp_notify_recv(struct seccomp_filter *filter, |
1178 | void __user *buf) | |
1179 | { | |
1180 | struct seccomp_knotif *knotif = NULL, *cur; | |
1181 | struct seccomp_notif unotif; | |
1182 | ssize_t ret; | |
1183 | ||
2882d53c SD |
1184 | /* Verify that we're not given garbage to keep struct extensible. */ |
1185 | ret = check_zeroed_user(buf, sizeof(unotif)); | |
1186 | if (ret < 0) | |
1187 | return ret; | |
1188 | if (!ret) | |
1189 | return -EINVAL; | |
1190 | ||
6a21cc50 TA |
1191 | memset(&unotif, 0, sizeof(unotif)); |
1192 | ||
1193 | ret = down_interruptible(&filter->notif->request); | |
1194 | if (ret < 0) | |
1195 | return ret; | |
1196 | ||
1197 | mutex_lock(&filter->notify_lock); | |
1198 | list_for_each_entry(cur, &filter->notif->notifications, list) { | |
1199 | if (cur->state == SECCOMP_NOTIFY_INIT) { | |
1200 | knotif = cur; | |
1201 | break; | |
1202 | } | |
1203 | } | |
1204 | ||
1205 | /* | |
1206 | * If we didn't find a notification, it could be that the task was | |
1207 | * interrupted by a fatal signal between the time we were woken and | |
1208 | * when we were able to acquire the rw lock. | |
1209 | */ | |
1210 | if (!knotif) { | |
1211 | ret = -ENOENT; | |
1212 | goto out; | |
1213 | } | |
1214 | ||
1215 | unotif.id = knotif->id; | |
1216 | unotif.pid = task_pid_vnr(knotif->task); | |
1217 | unotif.data = *(knotif->data); | |
1218 | ||
1219 | knotif->state = SECCOMP_NOTIFY_SENT; | |
76194c4e | 1220 | wake_up_poll(&filter->wqh, EPOLLOUT | EPOLLWRNORM); |
6a21cc50 TA |
1221 | ret = 0; |
1222 | out: | |
1223 | mutex_unlock(&filter->notify_lock); | |
1224 | ||
1225 | if (ret == 0 && copy_to_user(buf, &unotif, sizeof(unotif))) { | |
1226 | ret = -EFAULT; | |
1227 | ||
1228 | /* | |
1229 | * Userspace screwed up. To make sure that we keep this | |
1230 | * notification alive, let's reset it back to INIT. It | |
1231 | * may have died when we released the lock, so we need to make | |
1232 | * sure it's still around. | |
1233 | */ | |
6a21cc50 | 1234 | mutex_lock(&filter->notify_lock); |
9f87dcf1 | 1235 | knotif = find_notification(filter, unotif.id); |
6a21cc50 TA |
1236 | if (knotif) { |
1237 | knotif->state = SECCOMP_NOTIFY_INIT; | |
1238 | up(&filter->notif->request); | |
1239 | } | |
1240 | mutex_unlock(&filter->notify_lock); | |
1241 | } | |
1242 | ||
1243 | return ret; | |
1244 | } | |
1245 | ||
1246 | static long seccomp_notify_send(struct seccomp_filter *filter, | |
1247 | void __user *buf) | |
1248 | { | |
1249 | struct seccomp_notif_resp resp = {}; | |
9f87dcf1 | 1250 | struct seccomp_knotif *knotif; |
6a21cc50 TA |
1251 | long ret; |
1252 | ||
1253 | if (copy_from_user(&resp, buf, sizeof(resp))) | |
1254 | return -EFAULT; | |
1255 | ||
fb3c5386 CB |
1256 | if (resp.flags & ~SECCOMP_USER_NOTIF_FLAG_CONTINUE) |
1257 | return -EINVAL; | |
1258 | ||
1259 | if ((resp.flags & SECCOMP_USER_NOTIF_FLAG_CONTINUE) && | |
1260 | (resp.error || resp.val)) | |
6a21cc50 TA |
1261 | return -EINVAL; |
1262 | ||
1263 | ret = mutex_lock_interruptible(&filter->notify_lock); | |
1264 | if (ret < 0) | |
1265 | return ret; | |
1266 | ||
9f87dcf1 | 1267 | knotif = find_notification(filter, resp.id); |
6a21cc50 TA |
1268 | if (!knotif) { |
1269 | ret = -ENOENT; | |
1270 | goto out; | |
1271 | } | |
1272 | ||
1273 | /* Allow exactly one reply. */ | |
1274 | if (knotif->state != SECCOMP_NOTIFY_SENT) { | |
1275 | ret = -EINPROGRESS; | |
1276 | goto out; | |
1277 | } | |
1278 | ||
1279 | ret = 0; | |
1280 | knotif->state = SECCOMP_NOTIFY_REPLIED; | |
1281 | knotif->error = resp.error; | |
1282 | knotif->val = resp.val; | |
fb3c5386 | 1283 | knotif->flags = resp.flags; |
6a21cc50 TA |
1284 | complete(&knotif->ready); |
1285 | out: | |
1286 | mutex_unlock(&filter->notify_lock); | |
1287 | return ret; | |
1288 | } | |
1289 | ||
1290 | static long seccomp_notify_id_valid(struct seccomp_filter *filter, | |
1291 | void __user *buf) | |
1292 | { | |
9f87dcf1 | 1293 | struct seccomp_knotif *knotif; |
6a21cc50 TA |
1294 | u64 id; |
1295 | long ret; | |
1296 | ||
1297 | if (copy_from_user(&id, buf, sizeof(id))) | |
1298 | return -EFAULT; | |
1299 | ||
1300 | ret = mutex_lock_interruptible(&filter->notify_lock); | |
1301 | if (ret < 0) | |
1302 | return ret; | |
1303 | ||
9f87dcf1 SD |
1304 | knotif = find_notification(filter, id); |
1305 | if (knotif && knotif->state == SECCOMP_NOTIFY_SENT) | |
1306 | ret = 0; | |
1307 | else | |
1308 | ret = -ENOENT; | |
6a21cc50 | 1309 | |
6a21cc50 TA |
1310 | mutex_unlock(&filter->notify_lock); |
1311 | return ret; | |
1312 | } | |
1313 | ||
7cf97b12 SD |
1314 | static long seccomp_notify_addfd(struct seccomp_filter *filter, |
1315 | struct seccomp_notif_addfd __user *uaddfd, | |
1316 | unsigned int size) | |
1317 | { | |
1318 | struct seccomp_notif_addfd addfd; | |
1319 | struct seccomp_knotif *knotif; | |
1320 | struct seccomp_kaddfd kaddfd; | |
1321 | int ret; | |
1322 | ||
1323 | BUILD_BUG_ON(sizeof(addfd) < SECCOMP_NOTIFY_ADDFD_SIZE_VER0); | |
1324 | BUILD_BUG_ON(sizeof(addfd) != SECCOMP_NOTIFY_ADDFD_SIZE_LATEST); | |
1325 | ||
1326 | if (size < SECCOMP_NOTIFY_ADDFD_SIZE_VER0 || size >= PAGE_SIZE) | |
1327 | return -EINVAL; | |
1328 | ||
1329 | ret = copy_struct_from_user(&addfd, sizeof(addfd), uaddfd, size); | |
1330 | if (ret) | |
1331 | return ret; | |
1332 | ||
1333 | if (addfd.newfd_flags & ~O_CLOEXEC) | |
1334 | return -EINVAL; | |
1335 | ||
1336 | if (addfd.flags & ~SECCOMP_ADDFD_FLAG_SETFD) | |
1337 | return -EINVAL; | |
1338 | ||
1339 | if (addfd.newfd && !(addfd.flags & SECCOMP_ADDFD_FLAG_SETFD)) | |
1340 | return -EINVAL; | |
1341 | ||
1342 | kaddfd.file = fget(addfd.srcfd); | |
1343 | if (!kaddfd.file) | |
1344 | return -EBADF; | |
1345 | ||
1346 | kaddfd.flags = addfd.newfd_flags; | |
1347 | kaddfd.fd = (addfd.flags & SECCOMP_ADDFD_FLAG_SETFD) ? | |
1348 | addfd.newfd : -1; | |
1349 | init_completion(&kaddfd.completion); | |
1350 | ||
1351 | ret = mutex_lock_interruptible(&filter->notify_lock); | |
1352 | if (ret < 0) | |
1353 | goto out; | |
1354 | ||
1355 | knotif = find_notification(filter, addfd.id); | |
1356 | if (!knotif) { | |
1357 | ret = -ENOENT; | |
1358 | goto out_unlock; | |
1359 | } | |
1360 | ||
1361 | /* | |
1362 | * We do not want to allow for FD injection to occur before the | |
1363 | * notification has been picked up by a userspace handler, or after | |
1364 | * the notification has been replied to. | |
1365 | */ | |
1366 | if (knotif->state != SECCOMP_NOTIFY_SENT) { | |
1367 | ret = -EINPROGRESS; | |
1368 | goto out_unlock; | |
1369 | } | |
1370 | ||
1371 | list_add(&kaddfd.list, &knotif->addfd); | |
1372 | complete(&knotif->ready); | |
1373 | mutex_unlock(&filter->notify_lock); | |
1374 | ||
1375 | /* Now we wait for it to be processed or be interrupted */ | |
1376 | ret = wait_for_completion_interruptible(&kaddfd.completion); | |
1377 | if (ret == 0) { | |
1378 | /* | |
1379 | * We had a successful completion. The other side has already | |
1380 | * removed us from the addfd queue, and | |
1381 | * wait_for_completion_interruptible has a memory barrier upon | |
1382 | * success that lets us read this value directly without | |
1383 | * locking. | |
1384 | */ | |
1385 | ret = kaddfd.ret; | |
1386 | goto out; | |
1387 | } | |
1388 | ||
1389 | mutex_lock(&filter->notify_lock); | |
1390 | /* | |
1391 | * Even though we were woken up by a signal and not a successful | |
1392 | * completion, a completion may have happened in the mean time. | |
1393 | * | |
1394 | * We need to check again if the addfd request has been handled, | |
1395 | * and if not, we will remove it from the queue. | |
1396 | */ | |
1397 | if (list_empty(&kaddfd.list)) | |
1398 | ret = kaddfd.ret; | |
1399 | else | |
1400 | list_del(&kaddfd.list); | |
1401 | ||
1402 | out_unlock: | |
1403 | mutex_unlock(&filter->notify_lock); | |
1404 | out: | |
1405 | fput(kaddfd.file); | |
1406 | ||
1407 | return ret; | |
1408 | } | |
1409 | ||
6a21cc50 TA |
1410 | static long seccomp_notify_ioctl(struct file *file, unsigned int cmd, |
1411 | unsigned long arg) | |
1412 | { | |
1413 | struct seccomp_filter *filter = file->private_data; | |
1414 | void __user *buf = (void __user *)arg; | |
1415 | ||
7cf97b12 | 1416 | /* Fixed-size ioctls */ |
6a21cc50 TA |
1417 | switch (cmd) { |
1418 | case SECCOMP_IOCTL_NOTIF_RECV: | |
1419 | return seccomp_notify_recv(filter, buf); | |
1420 | case SECCOMP_IOCTL_NOTIF_SEND: | |
1421 | return seccomp_notify_send(filter, buf); | |
47e33c05 | 1422 | case SECCOMP_IOCTL_NOTIF_ID_VALID_WRONG_DIR: |
6a21cc50 TA |
1423 | case SECCOMP_IOCTL_NOTIF_ID_VALID: |
1424 | return seccomp_notify_id_valid(filter, buf); | |
7cf97b12 SD |
1425 | } |
1426 | ||
1427 | /* Extensible Argument ioctls */ | |
1428 | #define EA_IOCTL(cmd) ((cmd) & ~(IOC_INOUT | IOCSIZE_MASK)) | |
1429 | switch (EA_IOCTL(cmd)) { | |
1430 | case EA_IOCTL(SECCOMP_IOCTL_NOTIF_ADDFD): | |
1431 | return seccomp_notify_addfd(filter, buf, _IOC_SIZE(cmd)); | |
6a21cc50 TA |
1432 | default: |
1433 | return -EINVAL; | |
1434 | } | |
1435 | } | |
1436 | ||
1437 | static __poll_t seccomp_notify_poll(struct file *file, | |
1438 | struct poll_table_struct *poll_tab) | |
1439 | { | |
1440 | struct seccomp_filter *filter = file->private_data; | |
1441 | __poll_t ret = 0; | |
1442 | struct seccomp_knotif *cur; | |
1443 | ||
76194c4e | 1444 | poll_wait(file, &filter->wqh, poll_tab); |
6a21cc50 | 1445 | |
319deec7 | 1446 | if (mutex_lock_interruptible(&filter->notify_lock) < 0) |
6a21cc50 TA |
1447 | return EPOLLERR; |
1448 | ||
1449 | list_for_each_entry(cur, &filter->notif->notifications, list) { | |
1450 | if (cur->state == SECCOMP_NOTIFY_INIT) | |
1451 | ret |= EPOLLIN | EPOLLRDNORM; | |
1452 | if (cur->state == SECCOMP_NOTIFY_SENT) | |
1453 | ret |= EPOLLOUT | EPOLLWRNORM; | |
1454 | if ((ret & EPOLLIN) && (ret & EPOLLOUT)) | |
1455 | break; | |
1456 | } | |
1457 | ||
1458 | mutex_unlock(&filter->notify_lock); | |
1459 | ||
99cdb8b9 CB |
1460 | if (refcount_read(&filter->users) == 0) |
1461 | ret |= EPOLLHUP; | |
1462 | ||
6a21cc50 TA |
1463 | return ret; |
1464 | } | |
1465 | ||
1466 | static const struct file_operations seccomp_notify_ops = { | |
1467 | .poll = seccomp_notify_poll, | |
1468 | .release = seccomp_notify_release, | |
1469 | .unlocked_ioctl = seccomp_notify_ioctl, | |
3db81afd | 1470 | .compat_ioctl = seccomp_notify_ioctl, |
6a21cc50 TA |
1471 | }; |
1472 | ||
1473 | static struct file *init_listener(struct seccomp_filter *filter) | |
1474 | { | |
1475 | struct file *ret = ERR_PTR(-EBUSY); | |
1476 | struct seccomp_filter *cur; | |
1477 | ||
1478 | for (cur = current->seccomp.filter; cur; cur = cur->prev) { | |
1479 | if (cur->notif) | |
1480 | goto out; | |
1481 | } | |
1482 | ||
1483 | ret = ERR_PTR(-ENOMEM); | |
1484 | filter->notif = kzalloc(sizeof(*(filter->notif)), GFP_KERNEL); | |
1485 | if (!filter->notif) | |
1486 | goto out; | |
1487 | ||
1488 | sema_init(&filter->notif->request, 0); | |
1489 | filter->notif->next_id = get_random_u64(); | |
1490 | INIT_LIST_HEAD(&filter->notif->notifications); | |
6a21cc50 TA |
1491 | |
1492 | ret = anon_inode_getfile("seccomp notify", &seccomp_notify_ops, | |
1493 | filter, O_RDWR); | |
1494 | if (IS_ERR(ret)) | |
1495 | goto out_notif; | |
1496 | ||
1497 | /* The file has a reference to it now */ | |
1498 | __get_seccomp_filter(filter); | |
1499 | ||
1500 | out_notif: | |
1501 | if (IS_ERR(ret)) | |
e8393179 | 1502 | seccomp_notify_free(filter); |
6a21cc50 TA |
1503 | out: |
1504 | return ret; | |
1505 | } | |
1506 | ||
3b23dd12 KC |
1507 | /** |
1508 | * seccomp_set_mode_filter: internal function for setting seccomp filter | |
48dc92b9 | 1509 | * @flags: flags to change filter behavior |
3b23dd12 KC |
1510 | * @filter: struct sock_fprog containing filter |
1511 | * | |
1512 | * This function may be called repeatedly to install additional filters. | |
1513 | * Every filter successfully installed will be evaluated (in reverse order) | |
1514 | * for each system call the task makes. | |
1515 | * | |
1516 | * Once current->seccomp.mode is non-zero, it may not be changed. | |
1517 | * | |
1518 | * Returns 0 on success or -EINVAL on failure. | |
1519 | */ | |
48dc92b9 KC |
1520 | static long seccomp_set_mode_filter(unsigned int flags, |
1521 | const char __user *filter) | |
3b23dd12 KC |
1522 | { |
1523 | const unsigned long seccomp_mode = SECCOMP_MODE_FILTER; | |
c8bee430 | 1524 | struct seccomp_filter *prepared = NULL; |
3b23dd12 | 1525 | long ret = -EINVAL; |
6a21cc50 TA |
1526 | int listener = -1; |
1527 | struct file *listener_f = NULL; | |
3b23dd12 | 1528 | |
48dc92b9 | 1529 | /* Validate flags. */ |
c2e1f2e3 | 1530 | if (flags & ~SECCOMP_FILTER_FLAG_MASK) |
dbd95212 | 1531 | return -EINVAL; |
48dc92b9 | 1532 | |
7a0df7fb TA |
1533 | /* |
1534 | * In the successful case, NEW_LISTENER returns the new listener fd. | |
1535 | * But in the failure case, TSYNC returns the thread that died. If you | |
1536 | * combine these two flags, there's no way to tell whether something | |
51891498 TA |
1537 | * succeeded or failed. So, let's disallow this combination if the user |
1538 | * has not explicitly requested no errors from TSYNC. | |
7a0df7fb TA |
1539 | */ |
1540 | if ((flags & SECCOMP_FILTER_FLAG_TSYNC) && | |
51891498 TA |
1541 | (flags & SECCOMP_FILTER_FLAG_NEW_LISTENER) && |
1542 | ((flags & SECCOMP_FILTER_FLAG_TSYNC_ESRCH) == 0)) | |
7a0df7fb TA |
1543 | return -EINVAL; |
1544 | ||
c8bee430 KC |
1545 | /* Prepare the new filter before holding any locks. */ |
1546 | prepared = seccomp_prepare_user_filter(filter); | |
1547 | if (IS_ERR(prepared)) | |
1548 | return PTR_ERR(prepared); | |
1549 | ||
6a21cc50 TA |
1550 | if (flags & SECCOMP_FILTER_FLAG_NEW_LISTENER) { |
1551 | listener = get_unused_fd_flags(O_CLOEXEC); | |
1552 | if (listener < 0) { | |
1553 | ret = listener; | |
1554 | goto out_free; | |
1555 | } | |
1556 | ||
1557 | listener_f = init_listener(prepared); | |
1558 | if (IS_ERR(listener_f)) { | |
1559 | put_unused_fd(listener); | |
1560 | ret = PTR_ERR(listener_f); | |
1561 | goto out_free; | |
1562 | } | |
1563 | } | |
1564 | ||
c2e1f2e3 KC |
1565 | /* |
1566 | * Make sure we cannot change seccomp or nnp state via TSYNC | |
1567 | * while another thread is in the middle of calling exec. | |
1568 | */ | |
1569 | if (flags & SECCOMP_FILTER_FLAG_TSYNC && | |
1570 | mutex_lock_killable(¤t->signal->cred_guard_mutex)) | |
6a21cc50 | 1571 | goto out_put_fd; |
c2e1f2e3 | 1572 | |
dbd95212 KC |
1573 | spin_lock_irq(¤t->sighand->siglock); |
1574 | ||
3b23dd12 KC |
1575 | if (!seccomp_may_assign_mode(seccomp_mode)) |
1576 | goto out; | |
1577 | ||
c8bee430 | 1578 | ret = seccomp_attach_filter(flags, prepared); |
3b23dd12 | 1579 | if (ret) |
e2cfabdf | 1580 | goto out; |
c8bee430 KC |
1581 | /* Do not free the successfully attached filter. */ |
1582 | prepared = NULL; | |
1d9d02fe | 1583 | |
00a02d0c | 1584 | seccomp_assign_mode(current, seccomp_mode, flags); |
e2cfabdf | 1585 | out: |
dbd95212 | 1586 | spin_unlock_irq(¤t->sighand->siglock); |
c2e1f2e3 KC |
1587 | if (flags & SECCOMP_FILTER_FLAG_TSYNC) |
1588 | mutex_unlock(¤t->signal->cred_guard_mutex); | |
6a21cc50 TA |
1589 | out_put_fd: |
1590 | if (flags & SECCOMP_FILTER_FLAG_NEW_LISTENER) { | |
7a0df7fb | 1591 | if (ret) { |
a811dc61 | 1592 | listener_f->private_data = NULL; |
6a21cc50 TA |
1593 | fput(listener_f); |
1594 | put_unused_fd(listener); | |
a566a901 | 1595 | seccomp_notify_detach(prepared); |
6a21cc50 TA |
1596 | } else { |
1597 | fd_install(listener, listener_f); | |
1598 | ret = listener; | |
1599 | } | |
1600 | } | |
c2e1f2e3 | 1601 | out_free: |
c8bee430 | 1602 | seccomp_filter_free(prepared); |
1d9d02fe AA |
1603 | return ret; |
1604 | } | |
3b23dd12 | 1605 | #else |
48dc92b9 KC |
1606 | static inline long seccomp_set_mode_filter(unsigned int flags, |
1607 | const char __user *filter) | |
3b23dd12 KC |
1608 | { |
1609 | return -EINVAL; | |
1610 | } | |
1611 | #endif | |
d78ab02c | 1612 | |
d612b1fd TH |
1613 | static long seccomp_get_action_avail(const char __user *uaction) |
1614 | { | |
1615 | u32 action; | |
1616 | ||
1617 | if (copy_from_user(&action, uaction, sizeof(action))) | |
1618 | return -EFAULT; | |
1619 | ||
1620 | switch (action) { | |
0466bdb9 | 1621 | case SECCOMP_RET_KILL_PROCESS: |
fd76875c | 1622 | case SECCOMP_RET_KILL_THREAD: |
d612b1fd TH |
1623 | case SECCOMP_RET_TRAP: |
1624 | case SECCOMP_RET_ERRNO: | |
6a21cc50 | 1625 | case SECCOMP_RET_USER_NOTIF: |
d612b1fd | 1626 | case SECCOMP_RET_TRACE: |
59f5cf44 | 1627 | case SECCOMP_RET_LOG: |
d612b1fd TH |
1628 | case SECCOMP_RET_ALLOW: |
1629 | break; | |
1630 | default: | |
1631 | return -EOPNOTSUPP; | |
1632 | } | |
1633 | ||
1634 | return 0; | |
1635 | } | |
1636 | ||
6a21cc50 TA |
1637 | static long seccomp_get_notif_sizes(void __user *usizes) |
1638 | { | |
1639 | struct seccomp_notif_sizes sizes = { | |
1640 | .seccomp_notif = sizeof(struct seccomp_notif), | |
1641 | .seccomp_notif_resp = sizeof(struct seccomp_notif_resp), | |
1642 | .seccomp_data = sizeof(struct seccomp_data), | |
1643 | }; | |
1644 | ||
1645 | if (copy_to_user(usizes, &sizes, sizeof(sizes))) | |
1646 | return -EFAULT; | |
1647 | ||
1648 | return 0; | |
1649 | } | |
1650 | ||
48dc92b9 KC |
1651 | /* Common entry point for both prctl and syscall. */ |
1652 | static long do_seccomp(unsigned int op, unsigned int flags, | |
a5662e4d | 1653 | void __user *uargs) |
48dc92b9 KC |
1654 | { |
1655 | switch (op) { | |
1656 | case SECCOMP_SET_MODE_STRICT: | |
1657 | if (flags != 0 || uargs != NULL) | |
1658 | return -EINVAL; | |
1659 | return seccomp_set_mode_strict(); | |
1660 | case SECCOMP_SET_MODE_FILTER: | |
1661 | return seccomp_set_mode_filter(flags, uargs); | |
d612b1fd TH |
1662 | case SECCOMP_GET_ACTION_AVAIL: |
1663 | if (flags != 0) | |
1664 | return -EINVAL; | |
1665 | ||
1666 | return seccomp_get_action_avail(uargs); | |
6a21cc50 TA |
1667 | case SECCOMP_GET_NOTIF_SIZES: |
1668 | if (flags != 0) | |
1669 | return -EINVAL; | |
1670 | ||
1671 | return seccomp_get_notif_sizes(uargs); | |
48dc92b9 KC |
1672 | default: |
1673 | return -EINVAL; | |
1674 | } | |
1675 | } | |
1676 | ||
1677 | SYSCALL_DEFINE3(seccomp, unsigned int, op, unsigned int, flags, | |
a5662e4d | 1678 | void __user *, uargs) |
48dc92b9 KC |
1679 | { |
1680 | return do_seccomp(op, flags, uargs); | |
1681 | } | |
1682 | ||
d78ab02c KC |
1683 | /** |
1684 | * prctl_set_seccomp: configures current->seccomp.mode | |
1685 | * @seccomp_mode: requested mode to use | |
1686 | * @filter: optional struct sock_fprog for use with SECCOMP_MODE_FILTER | |
1687 | * | |
1688 | * Returns 0 on success or -EINVAL on failure. | |
1689 | */ | |
a5662e4d | 1690 | long prctl_set_seccomp(unsigned long seccomp_mode, void __user *filter) |
d78ab02c | 1691 | { |
48dc92b9 | 1692 | unsigned int op; |
a5662e4d | 1693 | void __user *uargs; |
48dc92b9 | 1694 | |
3b23dd12 KC |
1695 | switch (seccomp_mode) { |
1696 | case SECCOMP_MODE_STRICT: | |
48dc92b9 KC |
1697 | op = SECCOMP_SET_MODE_STRICT; |
1698 | /* | |
1699 | * Setting strict mode through prctl always ignored filter, | |
1700 | * so make sure it is always NULL here to pass the internal | |
1701 | * check in do_seccomp(). | |
1702 | */ | |
1703 | uargs = NULL; | |
1704 | break; | |
3b23dd12 | 1705 | case SECCOMP_MODE_FILTER: |
48dc92b9 KC |
1706 | op = SECCOMP_SET_MODE_FILTER; |
1707 | uargs = filter; | |
1708 | break; | |
3b23dd12 KC |
1709 | default: |
1710 | return -EINVAL; | |
1711 | } | |
48dc92b9 KC |
1712 | |
1713 | /* prctl interface doesn't have flags, so they are always zero. */ | |
1714 | return do_seccomp(op, 0, uargs); | |
d78ab02c | 1715 | } |
f8e529ed TA |
1716 | |
1717 | #if defined(CONFIG_SECCOMP_FILTER) && defined(CONFIG_CHECKPOINT_RESTORE) | |
f06eae83 TA |
1718 | static struct seccomp_filter *get_nth_filter(struct task_struct *task, |
1719 | unsigned long filter_off) | |
f8e529ed | 1720 | { |
f06eae83 TA |
1721 | struct seccomp_filter *orig, *filter; |
1722 | unsigned long count; | |
f8e529ed | 1723 | |
f06eae83 TA |
1724 | /* |
1725 | * Note: this is only correct because the caller should be the (ptrace) | |
1726 | * tracer of the task, otherwise lock_task_sighand is needed. | |
1727 | */ | |
f8e529ed | 1728 | spin_lock_irq(&task->sighand->siglock); |
f06eae83 | 1729 | |
f8e529ed | 1730 | if (task->seccomp.mode != SECCOMP_MODE_FILTER) { |
f06eae83 TA |
1731 | spin_unlock_irq(&task->sighand->siglock); |
1732 | return ERR_PTR(-EINVAL); | |
f8e529ed TA |
1733 | } |
1734 | ||
f06eae83 TA |
1735 | orig = task->seccomp.filter; |
1736 | __get_seccomp_filter(orig); | |
1737 | spin_unlock_irq(&task->sighand->siglock); | |
1738 | ||
1739 | count = 0; | |
1740 | for (filter = orig; filter; filter = filter->prev) | |
f8e529ed | 1741 | count++; |
f8e529ed TA |
1742 | |
1743 | if (filter_off >= count) { | |
f06eae83 | 1744 | filter = ERR_PTR(-ENOENT); |
f8e529ed TA |
1745 | goto out; |
1746 | } | |
f8e529ed | 1747 | |
f06eae83 TA |
1748 | count -= filter_off; |
1749 | for (filter = orig; filter && count > 1; filter = filter->prev) | |
f8e529ed | 1750 | count--; |
f8e529ed TA |
1751 | |
1752 | if (WARN_ON(count != 1 || !filter)) { | |
f06eae83 | 1753 | filter = ERR_PTR(-ENOENT); |
f8e529ed TA |
1754 | goto out; |
1755 | } | |
1756 | ||
f06eae83 TA |
1757 | __get_seccomp_filter(filter); |
1758 | ||
1759 | out: | |
1760 | __put_seccomp_filter(orig); | |
1761 | return filter; | |
1762 | } | |
1763 | ||
1764 | long seccomp_get_filter(struct task_struct *task, unsigned long filter_off, | |
1765 | void __user *data) | |
1766 | { | |
1767 | struct seccomp_filter *filter; | |
1768 | struct sock_fprog_kern *fprog; | |
1769 | long ret; | |
1770 | ||
1771 | if (!capable(CAP_SYS_ADMIN) || | |
1772 | current->seccomp.mode != SECCOMP_MODE_DISABLED) { | |
1773 | return -EACCES; | |
1774 | } | |
1775 | ||
1776 | filter = get_nth_filter(task, filter_off); | |
1777 | if (IS_ERR(filter)) | |
1778 | return PTR_ERR(filter); | |
1779 | ||
f8e529ed TA |
1780 | fprog = filter->prog->orig_prog; |
1781 | if (!fprog) { | |
470bf1f2 | 1782 | /* This must be a new non-cBPF filter, since we save |
f8e529ed TA |
1783 | * every cBPF filter's orig_prog above when |
1784 | * CONFIG_CHECKPOINT_RESTORE is enabled. | |
1785 | */ | |
1786 | ret = -EMEDIUMTYPE; | |
1787 | goto out; | |
1788 | } | |
1789 | ||
1790 | ret = fprog->len; | |
1791 | if (!data) | |
1792 | goto out; | |
1793 | ||
f8e529ed TA |
1794 | if (copy_to_user(data, fprog->filter, bpf_classic_proglen(fprog))) |
1795 | ret = -EFAULT; | |
1796 | ||
f8e529ed | 1797 | out: |
66a733ea | 1798 | __put_seccomp_filter(filter); |
f8e529ed | 1799 | return ret; |
f8e529ed | 1800 | } |
f8e529ed | 1801 | |
26500475 TA |
1802 | long seccomp_get_metadata(struct task_struct *task, |
1803 | unsigned long size, void __user *data) | |
1804 | { | |
1805 | long ret; | |
1806 | struct seccomp_filter *filter; | |
1807 | struct seccomp_metadata kmd = {}; | |
1808 | ||
1809 | if (!capable(CAP_SYS_ADMIN) || | |
1810 | current->seccomp.mode != SECCOMP_MODE_DISABLED) { | |
1811 | return -EACCES; | |
1812 | } | |
1813 | ||
1814 | size = min_t(unsigned long, size, sizeof(kmd)); | |
1815 | ||
63bb0045 TA |
1816 | if (size < sizeof(kmd.filter_off)) |
1817 | return -EINVAL; | |
1818 | ||
1819 | if (copy_from_user(&kmd.filter_off, data, sizeof(kmd.filter_off))) | |
26500475 TA |
1820 | return -EFAULT; |
1821 | ||
1822 | filter = get_nth_filter(task, kmd.filter_off); | |
1823 | if (IS_ERR(filter)) | |
1824 | return PTR_ERR(filter); | |
1825 | ||
26500475 TA |
1826 | if (filter->log) |
1827 | kmd.flags |= SECCOMP_FILTER_FLAG_LOG; | |
1828 | ||
1829 | ret = size; | |
1830 | if (copy_to_user(data, &kmd, size)) | |
1831 | ret = -EFAULT; | |
1832 | ||
1833 | __put_seccomp_filter(filter); | |
f8e529ed TA |
1834 | return ret; |
1835 | } | |
1836 | #endif | |
8e5f1ad1 TH |
1837 | |
1838 | #ifdef CONFIG_SYSCTL | |
1839 | ||
1840 | /* Human readable action names for friendly sysctl interaction */ | |
0466bdb9 | 1841 | #define SECCOMP_RET_KILL_PROCESS_NAME "kill_process" |
fd76875c | 1842 | #define SECCOMP_RET_KILL_THREAD_NAME "kill_thread" |
8e5f1ad1 TH |
1843 | #define SECCOMP_RET_TRAP_NAME "trap" |
1844 | #define SECCOMP_RET_ERRNO_NAME "errno" | |
6a21cc50 | 1845 | #define SECCOMP_RET_USER_NOTIF_NAME "user_notif" |
8e5f1ad1 | 1846 | #define SECCOMP_RET_TRACE_NAME "trace" |
59f5cf44 | 1847 | #define SECCOMP_RET_LOG_NAME "log" |
8e5f1ad1 TH |
1848 | #define SECCOMP_RET_ALLOW_NAME "allow" |
1849 | ||
fd76875c | 1850 | static const char seccomp_actions_avail[] = |
0466bdb9 | 1851 | SECCOMP_RET_KILL_PROCESS_NAME " " |
fd76875c KC |
1852 | SECCOMP_RET_KILL_THREAD_NAME " " |
1853 | SECCOMP_RET_TRAP_NAME " " | |
1854 | SECCOMP_RET_ERRNO_NAME " " | |
6a21cc50 | 1855 | SECCOMP_RET_USER_NOTIF_NAME " " |
fd76875c KC |
1856 | SECCOMP_RET_TRACE_NAME " " |
1857 | SECCOMP_RET_LOG_NAME " " | |
1858 | SECCOMP_RET_ALLOW_NAME; | |
8e5f1ad1 | 1859 | |
0ddec0fc TH |
1860 | struct seccomp_log_name { |
1861 | u32 log; | |
1862 | const char *name; | |
1863 | }; | |
1864 | ||
1865 | static const struct seccomp_log_name seccomp_log_names[] = { | |
0466bdb9 | 1866 | { SECCOMP_LOG_KILL_PROCESS, SECCOMP_RET_KILL_PROCESS_NAME }, |
fd76875c | 1867 | { SECCOMP_LOG_KILL_THREAD, SECCOMP_RET_KILL_THREAD_NAME }, |
0ddec0fc TH |
1868 | { SECCOMP_LOG_TRAP, SECCOMP_RET_TRAP_NAME }, |
1869 | { SECCOMP_LOG_ERRNO, SECCOMP_RET_ERRNO_NAME }, | |
6a21cc50 | 1870 | { SECCOMP_LOG_USER_NOTIF, SECCOMP_RET_USER_NOTIF_NAME }, |
0ddec0fc | 1871 | { SECCOMP_LOG_TRACE, SECCOMP_RET_TRACE_NAME }, |
59f5cf44 | 1872 | { SECCOMP_LOG_LOG, SECCOMP_RET_LOG_NAME }, |
0ddec0fc TH |
1873 | { SECCOMP_LOG_ALLOW, SECCOMP_RET_ALLOW_NAME }, |
1874 | { } | |
1875 | }; | |
1876 | ||
1877 | static bool seccomp_names_from_actions_logged(char *names, size_t size, | |
beb44aca TH |
1878 | u32 actions_logged, |
1879 | const char *sep) | |
0ddec0fc TH |
1880 | { |
1881 | const struct seccomp_log_name *cur; | |
beb44aca | 1882 | bool append_sep = false; |
0ddec0fc TH |
1883 | |
1884 | for (cur = seccomp_log_names; cur->name && size; cur++) { | |
1885 | ssize_t ret; | |
1886 | ||
1887 | if (!(actions_logged & cur->log)) | |
1888 | continue; | |
1889 | ||
beb44aca TH |
1890 | if (append_sep) { |
1891 | ret = strscpy(names, sep, size); | |
0ddec0fc TH |
1892 | if (ret < 0) |
1893 | return false; | |
1894 | ||
1895 | names += ret; | |
1896 | size -= ret; | |
1897 | } else | |
beb44aca | 1898 | append_sep = true; |
0ddec0fc TH |
1899 | |
1900 | ret = strscpy(names, cur->name, size); | |
1901 | if (ret < 0) | |
1902 | return false; | |
1903 | ||
1904 | names += ret; | |
1905 | size -= ret; | |
1906 | } | |
1907 | ||
1908 | return true; | |
1909 | } | |
1910 | ||
1911 | static bool seccomp_action_logged_from_name(u32 *action_logged, | |
1912 | const char *name) | |
1913 | { | |
1914 | const struct seccomp_log_name *cur; | |
1915 | ||
1916 | for (cur = seccomp_log_names; cur->name; cur++) { | |
1917 | if (!strcmp(cur->name, name)) { | |
1918 | *action_logged = cur->log; | |
1919 | return true; | |
1920 | } | |
1921 | } | |
1922 | ||
1923 | return false; | |
1924 | } | |
1925 | ||
1926 | static bool seccomp_actions_logged_from_names(u32 *actions_logged, char *names) | |
1927 | { | |
1928 | char *name; | |
1929 | ||
1930 | *actions_logged = 0; | |
1931 | while ((name = strsep(&names, " ")) && *name) { | |
1932 | u32 action_logged = 0; | |
1933 | ||
1934 | if (!seccomp_action_logged_from_name(&action_logged, name)) | |
1935 | return false; | |
1936 | ||
1937 | *actions_logged |= action_logged; | |
1938 | } | |
1939 | ||
1940 | return true; | |
1941 | } | |
1942 | ||
d013db02 TH |
1943 | static int read_actions_logged(struct ctl_table *ro_table, void __user *buffer, |
1944 | size_t *lenp, loff_t *ppos) | |
0ddec0fc TH |
1945 | { |
1946 | char names[sizeof(seccomp_actions_avail)]; | |
1947 | struct ctl_table table; | |
d013db02 TH |
1948 | |
1949 | memset(names, 0, sizeof(names)); | |
1950 | ||
1951 | if (!seccomp_names_from_actions_logged(names, sizeof(names), | |
beb44aca | 1952 | seccomp_actions_logged, " ")) |
d013db02 TH |
1953 | return -EINVAL; |
1954 | ||
1955 | table = *ro_table; | |
1956 | table.data = names; | |
1957 | table.maxlen = sizeof(names); | |
1958 | return proc_dostring(&table, 0, buffer, lenp, ppos); | |
1959 | } | |
1960 | ||
1961 | static int write_actions_logged(struct ctl_table *ro_table, void __user *buffer, | |
ea6eca77 | 1962 | size_t *lenp, loff_t *ppos, u32 *actions_logged) |
0ddec0fc TH |
1963 | { |
1964 | char names[sizeof(seccomp_actions_avail)]; | |
1965 | struct ctl_table table; | |
1966 | int ret; | |
1967 | ||
d013db02 | 1968 | if (!capable(CAP_SYS_ADMIN)) |
0ddec0fc TH |
1969 | return -EPERM; |
1970 | ||
1971 | memset(names, 0, sizeof(names)); | |
1972 | ||
0ddec0fc TH |
1973 | table = *ro_table; |
1974 | table.data = names; | |
1975 | table.maxlen = sizeof(names); | |
d013db02 | 1976 | ret = proc_dostring(&table, 1, buffer, lenp, ppos); |
0ddec0fc TH |
1977 | if (ret) |
1978 | return ret; | |
1979 | ||
ea6eca77 | 1980 | if (!seccomp_actions_logged_from_names(actions_logged, table.data)) |
d013db02 | 1981 | return -EINVAL; |
0ddec0fc | 1982 | |
ea6eca77 | 1983 | if (*actions_logged & SECCOMP_LOG_ALLOW) |
d013db02 | 1984 | return -EINVAL; |
0ddec0fc | 1985 | |
ea6eca77 | 1986 | seccomp_actions_logged = *actions_logged; |
0ddec0fc TH |
1987 | return 0; |
1988 | } | |
0ddec0fc | 1989 | |
ea6eca77 TH |
1990 | static void audit_actions_logged(u32 actions_logged, u32 old_actions_logged, |
1991 | int ret) | |
1992 | { | |
1993 | char names[sizeof(seccomp_actions_avail)]; | |
1994 | char old_names[sizeof(seccomp_actions_avail)]; | |
1995 | const char *new = names; | |
1996 | const char *old = old_names; | |
0ddec0fc | 1997 | |
ea6eca77 TH |
1998 | if (!audit_enabled) |
1999 | return; | |
2000 | ||
2001 | memset(names, 0, sizeof(names)); | |
2002 | memset(old_names, 0, sizeof(old_names)); | |
2003 | ||
2004 | if (ret) | |
2005 | new = "?"; | |
2006 | else if (!actions_logged) | |
2007 | new = "(none)"; | |
2008 | else if (!seccomp_names_from_actions_logged(names, sizeof(names), | |
2009 | actions_logged, ",")) | |
2010 | new = "?"; | |
2011 | ||
2012 | if (!old_actions_logged) | |
2013 | old = "(none)"; | |
2014 | else if (!seccomp_names_from_actions_logged(old_names, | |
2015 | sizeof(old_names), | |
2016 | old_actions_logged, ",")) | |
2017 | old = "?"; | |
2018 | ||
2019 | return audit_seccomp_actions_logged(new, old, !ret); | |
2020 | } | |
2021 | ||
d013db02 | 2022 | static int seccomp_actions_logged_handler(struct ctl_table *ro_table, int write, |
32927393 | 2023 | void *buffer, size_t *lenp, |
d013db02 TH |
2024 | loff_t *ppos) |
2025 | { | |
ea6eca77 TH |
2026 | int ret; |
2027 | ||
2028 | if (write) { | |
2029 | u32 actions_logged = 0; | |
2030 | u32 old_actions_logged = seccomp_actions_logged; | |
2031 | ||
2032 | ret = write_actions_logged(ro_table, buffer, lenp, ppos, | |
2033 | &actions_logged); | |
2034 | audit_actions_logged(actions_logged, old_actions_logged, ret); | |
2035 | } else | |
2036 | ret = read_actions_logged(ro_table, buffer, lenp, ppos); | |
2037 | ||
2038 | return ret; | |
0ddec0fc TH |
2039 | } |
2040 | ||
8e5f1ad1 TH |
2041 | static struct ctl_path seccomp_sysctl_path[] = { |
2042 | { .procname = "kernel", }, | |
2043 | { .procname = "seccomp", }, | |
2044 | { } | |
2045 | }; | |
2046 | ||
2047 | static struct ctl_table seccomp_sysctl_table[] = { | |
2048 | { | |
2049 | .procname = "actions_avail", | |
2050 | .data = (void *) &seccomp_actions_avail, | |
2051 | .maxlen = sizeof(seccomp_actions_avail), | |
2052 | .mode = 0444, | |
2053 | .proc_handler = proc_dostring, | |
2054 | }, | |
0ddec0fc TH |
2055 | { |
2056 | .procname = "actions_logged", | |
2057 | .mode = 0644, | |
2058 | .proc_handler = seccomp_actions_logged_handler, | |
2059 | }, | |
8e5f1ad1 TH |
2060 | { } |
2061 | }; | |
2062 | ||
2063 | static int __init seccomp_sysctl_init(void) | |
2064 | { | |
2065 | struct ctl_table_header *hdr; | |
2066 | ||
2067 | hdr = register_sysctl_paths(seccomp_sysctl_path, seccomp_sysctl_table); | |
2068 | if (!hdr) | |
e68f9d49 | 2069 | pr_warn("sysctl registration failed\n"); |
8e5f1ad1 TH |
2070 | else |
2071 | kmemleak_not_leak(hdr); | |
2072 | ||
2073 | return 0; | |
2074 | } | |
2075 | ||
2076 | device_initcall(seccomp_sysctl_init) | |
2077 | ||
2078 | #endif /* CONFIG_SYSCTL */ |