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> |
fb14528e | 41 | #include <linux/capability.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. | |
0ae71c77 | 110 | * @ioctl_flags: The flags used for the seccomp_addfd ioctl. |
7cf97b12 SD |
111 | * @ret: The return value of the installing process. It is set to the fd num |
112 | * upon success (>= 0). | |
113 | * @completion: Indicates that the installing process has completed fd | |
114 | * installation, or gone away (either due to successful | |
115 | * reply, or signal) | |
116 | * | |
117 | */ | |
118 | struct seccomp_kaddfd { | |
119 | struct file *file; | |
120 | int fd; | |
121 | unsigned int flags; | |
0ae71c77 | 122 | __u32 ioctl_flags; |
7cf97b12 | 123 | |
42eb0d54 CH |
124 | union { |
125 | bool setfd; | |
126 | /* To only be set on reply */ | |
127 | int ret; | |
128 | }; | |
7cf97b12 SD |
129 | struct completion completion; |
130 | struct list_head list; | |
6a21cc50 TA |
131 | }; |
132 | ||
133 | /** | |
134 | * struct notification - container for seccomp userspace notifications. Since | |
135 | * most seccomp filters will not have notification listeners attached and this | |
136 | * structure is fairly large, we store the notification-specific stuff in a | |
137 | * separate structure. | |
138 | * | |
139 | * @request: A semaphore that users of this notification can wait on for | |
140 | * changes. Actual reads and writes are still controlled with | |
141 | * filter->notify_lock. | |
142 | * @next_id: The id of the next request. | |
143 | * @notifications: A list of struct seccomp_knotif elements. | |
6a21cc50 TA |
144 | */ |
145 | struct notification { | |
146 | struct semaphore request; | |
147 | u64 next_id; | |
148 | struct list_head notifications; | |
6a21cc50 | 149 | }; |
e2cfabdf | 150 | |
f9d480b6 YZ |
151 | #ifdef SECCOMP_ARCH_NATIVE |
152 | /** | |
153 | * struct action_cache - per-filter cache of seccomp actions per | |
154 | * arch/syscall pair | |
155 | * | |
156 | * @allow_native: A bitmap where each bit represents whether the | |
157 | * filter will always allow the syscall, for the | |
158 | * native architecture. | |
159 | * @allow_compat: A bitmap where each bit represents whether the | |
160 | * filter will always allow the syscall, for the | |
161 | * compat architecture. | |
162 | */ | |
163 | struct action_cache { | |
164 | DECLARE_BITMAP(allow_native, SECCOMP_ARCH_NATIVE_NR); | |
165 | #ifdef SECCOMP_ARCH_COMPAT | |
166 | DECLARE_BITMAP(allow_compat, SECCOMP_ARCH_COMPAT_NR); | |
167 | #endif | |
168 | }; | |
169 | #else | |
170 | struct action_cache { }; | |
171 | ||
172 | static inline bool seccomp_cache_check_allow(const struct seccomp_filter *sfilter, | |
173 | const struct seccomp_data *sd) | |
174 | { | |
175 | return false; | |
176 | } | |
8e01b51a YZ |
177 | |
178 | static inline void seccomp_cache_prepare(struct seccomp_filter *sfilter) | |
179 | { | |
180 | } | |
f9d480b6 YZ |
181 | #endif /* SECCOMP_ARCH_NATIVE */ |
182 | ||
e2cfabdf WD |
183 | /** |
184 | * struct seccomp_filter - container for seccomp BPF programs | |
185 | * | |
b707ddee CB |
186 | * @refs: Reference count to manage the object lifetime. |
187 | * A filter's reference count is incremented for each directly | |
188 | * attached task, once for the dependent filter, and if | |
189 | * requested for the user notifier. When @refs reaches zero, | |
190 | * the filter can be freed. | |
99cdb8b9 CB |
191 | * @users: A filter's @users count is incremented for each directly |
192 | * attached task (filter installation, fork(), thread_sync), | |
193 | * and once for the dependent filter (tracked in filter->prev). | |
194 | * When it reaches zero it indicates that no direct or indirect | |
195 | * users of that filter exist. No new tasks can get associated with | |
196 | * this filter after reaching 0. The @users count is always smaller | |
197 | * or equal to @refs. Hence, reaching 0 for @users does not mean | |
198 | * the filter can be freed. | |
8e01b51a | 199 | * @cache: cache of arch/syscall mappings to actions |
e66a3997 | 200 | * @log: true if all actions except for SECCOMP_RET_ALLOW should be logged |
e2cfabdf | 201 | * @prev: points to a previously installed, or inherited, filter |
285fdfc5 | 202 | * @prog: the BPF program to evaluate |
6a21cc50 TA |
203 | * @notif: the struct that holds all notification related information |
204 | * @notify_lock: A lock for all notification-related accesses. | |
76194c4e | 205 | * @wqh: A wait queue for poll if a notifier is in use. |
e2cfabdf WD |
206 | * |
207 | * seccomp_filter objects are organized in a tree linked via the @prev | |
208 | * pointer. For any task, it appears to be a singly-linked list starting | |
209 | * with current->seccomp.filter, the most recently attached or inherited filter. | |
210 | * However, multiple filters may share a @prev node, by way of fork(), which | |
211 | * results in a unidirectional tree existing in memory. This is similar to | |
212 | * how namespaces work. | |
213 | * | |
214 | * seccomp_filter objects should never be modified after being attached | |
b707ddee | 215 | * to a task_struct (other than @refs). |
e2cfabdf WD |
216 | */ |
217 | struct seccomp_filter { | |
b707ddee | 218 | refcount_t refs; |
99cdb8b9 | 219 | refcount_t users; |
e66a3997 | 220 | bool log; |
8e01b51a | 221 | struct action_cache cache; |
e2cfabdf | 222 | struct seccomp_filter *prev; |
7ae457c1 | 223 | struct bpf_prog *prog; |
6a21cc50 TA |
224 | struct notification *notif; |
225 | struct mutex notify_lock; | |
76194c4e | 226 | wait_queue_head_t wqh; |
e2cfabdf WD |
227 | }; |
228 | ||
229 | /* Limit any path through the tree to 256KB worth of instructions. */ | |
230 | #define MAX_INSNS_PER_PATH ((1 << 18) / sizeof(struct sock_filter)) | |
231 | ||
bd4cf0ed | 232 | /* |
e2cfabdf WD |
233 | * Endianness is explicitly ignored and left for BPF program authors to manage |
234 | * as per the specific architecture. | |
235 | */ | |
bd4cf0ed | 236 | static void populate_seccomp_data(struct seccomp_data *sd) |
e2cfabdf | 237 | { |
2d9ca267 DE |
238 | /* |
239 | * Instead of using current_pt_reg(), we're already doing the work | |
240 | * to safely fetch "current", so just use "task" everywhere below. | |
241 | */ | |
bd4cf0ed AS |
242 | struct task_struct *task = current; |
243 | struct pt_regs *regs = task_pt_regs(task); | |
2eac7648 | 244 | unsigned long args[6]; |
e2cfabdf | 245 | |
bd4cf0ed | 246 | sd->nr = syscall_get_nr(task, regs); |
16add411 | 247 | sd->arch = syscall_get_arch(task); |
b35f549d | 248 | syscall_get_arguments(task, regs, args); |
2eac7648 DB |
249 | sd->args[0] = args[0]; |
250 | sd->args[1] = args[1]; | |
251 | sd->args[2] = args[2]; | |
252 | sd->args[3] = args[3]; | |
253 | sd->args[4] = args[4]; | |
254 | sd->args[5] = args[5]; | |
bd4cf0ed | 255 | sd->instruction_pointer = KSTK_EIP(task); |
e2cfabdf WD |
256 | } |
257 | ||
258 | /** | |
259 | * seccomp_check_filter - verify seccomp filter code | |
260 | * @filter: filter to verify | |
261 | * @flen: length of filter | |
262 | * | |
4df95ff4 | 263 | * Takes a previously checked filter (by bpf_check_classic) and |
e2cfabdf WD |
264 | * redirects all filter code that loads struct sk_buff data |
265 | * and related data through seccomp_bpf_load. It also | |
266 | * enforces length and alignment checking of those loads. | |
267 | * | |
268 | * Returns 0 if the rule set is legal or -EINVAL if not. | |
269 | */ | |
270 | static int seccomp_check_filter(struct sock_filter *filter, unsigned int flen) | |
271 | { | |
272 | int pc; | |
273 | for (pc = 0; pc < flen; pc++) { | |
274 | struct sock_filter *ftest = &filter[pc]; | |
275 | u16 code = ftest->code; | |
276 | u32 k = ftest->k; | |
277 | ||
278 | switch (code) { | |
34805931 | 279 | case BPF_LD | BPF_W | BPF_ABS: |
bd4cf0ed | 280 | ftest->code = BPF_LDX | BPF_W | BPF_ABS; |
e2cfabdf WD |
281 | /* 32-bit aligned and not out of bounds. */ |
282 | if (k >= sizeof(struct seccomp_data) || k & 3) | |
283 | return -EINVAL; | |
284 | continue; | |
34805931 | 285 | case BPF_LD | BPF_W | BPF_LEN: |
bd4cf0ed | 286 | ftest->code = BPF_LD | BPF_IMM; |
e2cfabdf WD |
287 | ftest->k = sizeof(struct seccomp_data); |
288 | continue; | |
34805931 | 289 | case BPF_LDX | BPF_W | BPF_LEN: |
bd4cf0ed | 290 | ftest->code = BPF_LDX | BPF_IMM; |
e2cfabdf WD |
291 | ftest->k = sizeof(struct seccomp_data); |
292 | continue; | |
293 | /* Explicitly include allowed calls. */ | |
34805931 DB |
294 | case BPF_RET | BPF_K: |
295 | case BPF_RET | BPF_A: | |
296 | case BPF_ALU | BPF_ADD | BPF_K: | |
297 | case BPF_ALU | BPF_ADD | BPF_X: | |
298 | case BPF_ALU | BPF_SUB | BPF_K: | |
299 | case BPF_ALU | BPF_SUB | BPF_X: | |
300 | case BPF_ALU | BPF_MUL | BPF_K: | |
301 | case BPF_ALU | BPF_MUL | BPF_X: | |
302 | case BPF_ALU | BPF_DIV | BPF_K: | |
303 | case BPF_ALU | BPF_DIV | BPF_X: | |
304 | case BPF_ALU | BPF_AND | BPF_K: | |
305 | case BPF_ALU | BPF_AND | BPF_X: | |
306 | case BPF_ALU | BPF_OR | BPF_K: | |
307 | case BPF_ALU | BPF_OR | BPF_X: | |
308 | case BPF_ALU | BPF_XOR | BPF_K: | |
309 | case BPF_ALU | BPF_XOR | BPF_X: | |
310 | case BPF_ALU | BPF_LSH | BPF_K: | |
311 | case BPF_ALU | BPF_LSH | BPF_X: | |
312 | case BPF_ALU | BPF_RSH | BPF_K: | |
313 | case BPF_ALU | BPF_RSH | BPF_X: | |
314 | case BPF_ALU | BPF_NEG: | |
315 | case BPF_LD | BPF_IMM: | |
316 | case BPF_LDX | BPF_IMM: | |
317 | case BPF_MISC | BPF_TAX: | |
318 | case BPF_MISC | BPF_TXA: | |
319 | case BPF_LD | BPF_MEM: | |
320 | case BPF_LDX | BPF_MEM: | |
321 | case BPF_ST: | |
322 | case BPF_STX: | |
323 | case BPF_JMP | BPF_JA: | |
324 | case BPF_JMP | BPF_JEQ | BPF_K: | |
325 | case BPF_JMP | BPF_JEQ | BPF_X: | |
326 | case BPF_JMP | BPF_JGE | BPF_K: | |
327 | case BPF_JMP | BPF_JGE | BPF_X: | |
328 | case BPF_JMP | BPF_JGT | BPF_K: | |
329 | case BPF_JMP | BPF_JGT | BPF_X: | |
330 | case BPF_JMP | BPF_JSET | BPF_K: | |
331 | case BPF_JMP | BPF_JSET | BPF_X: | |
e2cfabdf WD |
332 | continue; |
333 | default: | |
334 | return -EINVAL; | |
335 | } | |
336 | } | |
337 | return 0; | |
338 | } | |
339 | ||
f9d480b6 YZ |
340 | #ifdef SECCOMP_ARCH_NATIVE |
341 | static inline bool seccomp_cache_check_allow_bitmap(const void *bitmap, | |
342 | size_t bitmap_size, | |
343 | int syscall_nr) | |
344 | { | |
345 | if (unlikely(syscall_nr < 0 || syscall_nr >= bitmap_size)) | |
346 | return false; | |
347 | syscall_nr = array_index_nospec(syscall_nr, bitmap_size); | |
348 | ||
349 | return test_bit(syscall_nr, bitmap); | |
350 | } | |
351 | ||
352 | /** | |
353 | * seccomp_cache_check_allow - lookup seccomp cache | |
354 | * @sfilter: The seccomp filter | |
355 | * @sd: The seccomp data to lookup the cache with | |
356 | * | |
357 | * Returns true if the seccomp_data is cached and allowed. | |
358 | */ | |
359 | static inline bool seccomp_cache_check_allow(const struct seccomp_filter *sfilter, | |
360 | const struct seccomp_data *sd) | |
361 | { | |
362 | int syscall_nr = sd->nr; | |
363 | const struct action_cache *cache = &sfilter->cache; | |
364 | ||
365 | #ifndef SECCOMP_ARCH_COMPAT | |
366 | /* A native-only architecture doesn't need to check sd->arch. */ | |
367 | return seccomp_cache_check_allow_bitmap(cache->allow_native, | |
368 | SECCOMP_ARCH_NATIVE_NR, | |
369 | syscall_nr); | |
370 | #else | |
371 | if (likely(sd->arch == SECCOMP_ARCH_NATIVE)) | |
372 | return seccomp_cache_check_allow_bitmap(cache->allow_native, | |
373 | SECCOMP_ARCH_NATIVE_NR, | |
374 | syscall_nr); | |
375 | if (likely(sd->arch == SECCOMP_ARCH_COMPAT)) | |
376 | return seccomp_cache_check_allow_bitmap(cache->allow_compat, | |
377 | SECCOMP_ARCH_COMPAT_NR, | |
378 | syscall_nr); | |
379 | #endif /* SECCOMP_ARCH_COMPAT */ | |
380 | ||
381 | WARN_ON_ONCE(true); | |
382 | return false; | |
383 | } | |
384 | #endif /* SECCOMP_ARCH_NATIVE */ | |
385 | ||
e2cfabdf | 386 | /** |
285fdfc5 MS |
387 | * seccomp_run_filters - evaluates all seccomp filters against @sd |
388 | * @sd: optional seccomp data to be passed to filters | |
deb4de8b KC |
389 | * @match: stores struct seccomp_filter that resulted in the return value, |
390 | * unless filter returned SECCOMP_RET_ALLOW, in which case it will | |
391 | * be unchanged. | |
e2cfabdf WD |
392 | * |
393 | * Returns valid seccomp BPF response codes. | |
394 | */ | |
0466bdb9 | 395 | #define ACTION_ONLY(ret) ((s32)((ret) & (SECCOMP_RET_ACTION_FULL))) |
deb4de8b KC |
396 | static u32 seccomp_run_filters(const struct seccomp_data *sd, |
397 | struct seccomp_filter **match) | |
e2cfabdf | 398 | { |
acf3b2c7 | 399 | u32 ret = SECCOMP_RET_ALLOW; |
8225d385 PK |
400 | /* Make sure cross-thread synced filter points somewhere sane. */ |
401 | struct seccomp_filter *f = | |
506458ef | 402 | READ_ONCE(current->seccomp.filter); |
acf3b2c7 WD |
403 | |
404 | /* Ensure unexpected behavior doesn't result in failing open. */ | |
0d42d73a | 405 | if (WARN_ON(f == NULL)) |
4d3b0b05 | 406 | return SECCOMP_RET_KILL_PROCESS; |
acf3b2c7 | 407 | |
f9d480b6 YZ |
408 | if (seccomp_cache_check_allow(f, sd)) |
409 | return SECCOMP_RET_ALLOW; | |
410 | ||
e2cfabdf WD |
411 | /* |
412 | * All filters in the list are evaluated and the lowest BPF return | |
acf3b2c7 | 413 | * value always takes priority (ignoring the DATA). |
e2cfabdf | 414 | */ |
3ba2530c | 415 | for (; f; f = f->prev) { |
3d9f773c | 416 | u32 cur_ret = bpf_prog_run_pin_on_cpu(f->prog, sd); |
8f577cad | 417 | |
0466bdb9 | 418 | if (ACTION_ONLY(cur_ret) < ACTION_ONLY(ret)) { |
acf3b2c7 | 419 | ret = cur_ret; |
deb4de8b KC |
420 | *match = f; |
421 | } | |
e2cfabdf WD |
422 | } |
423 | return ret; | |
424 | } | |
1f41b450 | 425 | #endif /* CONFIG_SECCOMP_FILTER */ |
e2cfabdf | 426 | |
1f41b450 KC |
427 | static inline bool seccomp_may_assign_mode(unsigned long seccomp_mode) |
428 | { | |
69f6a34b | 429 | assert_spin_locked(¤t->sighand->siglock); |
dbd95212 | 430 | |
1f41b450 KC |
431 | if (current->seccomp.mode && current->seccomp.mode != seccomp_mode) |
432 | return false; | |
433 | ||
434 | return true; | |
435 | } | |
436 | ||
8bf37d8c | 437 | void __weak arch_seccomp_spec_mitigate(struct task_struct *task) { } |
5c307089 | 438 | |
3ba2530c | 439 | static inline void seccomp_assign_mode(struct task_struct *task, |
00a02d0c KC |
440 | unsigned long seccomp_mode, |
441 | unsigned long flags) | |
1f41b450 | 442 | { |
69f6a34b | 443 | assert_spin_locked(&task->sighand->siglock); |
dbd95212 | 444 | |
3ba2530c KC |
445 | task->seccomp.mode = seccomp_mode; |
446 | /* | |
23d67a54 | 447 | * Make sure SYSCALL_WORK_SECCOMP cannot be set before the mode (and |
3ba2530c KC |
448 | * filter) is set. |
449 | */ | |
450 | smp_mb__before_atomic(); | |
00a02d0c KC |
451 | /* Assume default seccomp processes want spec flaw mitigation. */ |
452 | if ((flags & SECCOMP_FILTER_FLAG_SPEC_ALLOW) == 0) | |
8bf37d8c | 453 | arch_seccomp_spec_mitigate(task); |
23d67a54 | 454 | set_task_syscall_work(task, SECCOMP); |
1f41b450 KC |
455 | } |
456 | ||
457 | #ifdef CONFIG_SECCOMP_FILTER | |
c2e1f2e3 KC |
458 | /* Returns 1 if the parent is an ancestor of the child. */ |
459 | static int is_ancestor(struct seccomp_filter *parent, | |
460 | struct seccomp_filter *child) | |
461 | { | |
462 | /* NULL is the root ancestor. */ | |
463 | if (parent == NULL) | |
464 | return 1; | |
465 | for (; child; child = child->prev) | |
466 | if (child == parent) | |
467 | return 1; | |
468 | return 0; | |
469 | } | |
470 | ||
471 | /** | |
472 | * seccomp_can_sync_threads: checks if all threads can be synchronized | |
473 | * | |
474 | * Expects sighand and cred_guard_mutex locks to be held. | |
475 | * | |
476 | * Returns 0 on success, -ve on error, or the pid of a thread which was | |
6beff00b | 477 | * either not in the correct seccomp mode or did not have an ancestral |
c2e1f2e3 KC |
478 | * seccomp filter. |
479 | */ | |
480 | static inline pid_t seccomp_can_sync_threads(void) | |
481 | { | |
482 | struct task_struct *thread, *caller; | |
483 | ||
484 | BUG_ON(!mutex_is_locked(¤t->signal->cred_guard_mutex)); | |
69f6a34b | 485 | assert_spin_locked(¤t->sighand->siglock); |
c2e1f2e3 KC |
486 | |
487 | /* Validate all threads being eligible for synchronization. */ | |
488 | caller = current; | |
489 | for_each_thread(caller, thread) { | |
490 | pid_t failed; | |
491 | ||
492 | /* Skip current, since it is initiating the sync. */ | |
493 | if (thread == caller) | |
494 | continue; | |
495 | ||
496 | if (thread->seccomp.mode == SECCOMP_MODE_DISABLED || | |
497 | (thread->seccomp.mode == SECCOMP_MODE_FILTER && | |
498 | is_ancestor(thread->seccomp.filter, | |
499 | caller->seccomp.filter))) | |
500 | continue; | |
501 | ||
502 | /* Return the first thread that cannot be synchronized. */ | |
503 | failed = task_pid_vnr(thread); | |
504 | /* If the pid cannot be resolved, then return -ESRCH */ | |
0d42d73a | 505 | if (WARN_ON(failed == 0)) |
c2e1f2e3 KC |
506 | failed = -ESRCH; |
507 | return failed; | |
508 | } | |
509 | ||
510 | return 0; | |
511 | } | |
512 | ||
3a15fb6e CB |
513 | static inline void seccomp_filter_free(struct seccomp_filter *filter) |
514 | { | |
515 | if (filter) { | |
516 | bpf_prog_destroy(filter->prog); | |
517 | kfree(filter); | |
518 | } | |
519 | } | |
520 | ||
99cdb8b9 CB |
521 | static void __seccomp_filter_orphan(struct seccomp_filter *orig) |
522 | { | |
523 | while (orig && refcount_dec_and_test(&orig->users)) { | |
524 | if (waitqueue_active(&orig->wqh)) | |
525 | wake_up_poll(&orig->wqh, EPOLLHUP); | |
526 | orig = orig->prev; | |
527 | } | |
528 | } | |
529 | ||
3a15fb6e CB |
530 | static void __put_seccomp_filter(struct seccomp_filter *orig) |
531 | { | |
532 | /* Clean up single-reference branches iteratively. */ | |
533 | while (orig && refcount_dec_and_test(&orig->refs)) { | |
534 | struct seccomp_filter *freeme = orig; | |
535 | orig = orig->prev; | |
536 | seccomp_filter_free(freeme); | |
537 | } | |
538 | } | |
539 | ||
99cdb8b9 CB |
540 | static void __seccomp_filter_release(struct seccomp_filter *orig) |
541 | { | |
542 | /* Notify about any unused filters in the task's former filter tree. */ | |
543 | __seccomp_filter_orphan(orig); | |
544 | /* Finally drop all references to the task's former tree. */ | |
545 | __put_seccomp_filter(orig); | |
546 | } | |
547 | ||
3a15fb6e | 548 | /** |
99cdb8b9 CB |
549 | * seccomp_filter_release - Detach the task from its filter tree, |
550 | * drop its reference count, and notify | |
551 | * about unused filters | |
3a15fb6e CB |
552 | * |
553 | * This function should only be called when the task is exiting as | |
554 | * it detaches it from its filter tree. As such, READ_ONCE() and | |
555 | * barriers are not needed here, as would normally be needed. | |
556 | */ | |
557 | void seccomp_filter_release(struct task_struct *tsk) | |
558 | { | |
559 | struct seccomp_filter *orig = tsk->seccomp.filter; | |
560 | ||
0d8315dd YZ |
561 | /* We are effectively holding the siglock by not having any sighand. */ |
562 | WARN_ON(tsk->sighand != NULL); | |
563 | ||
3a15fb6e CB |
564 | /* Detach task from its filter tree. */ |
565 | tsk->seccomp.filter = NULL; | |
99cdb8b9 | 566 | __seccomp_filter_release(orig); |
3a15fb6e CB |
567 | } |
568 | ||
c2e1f2e3 KC |
569 | /** |
570 | * seccomp_sync_threads: sets all threads to use current's filter | |
571 | * | |
572 | * Expects sighand and cred_guard_mutex locks to be held, and for | |
573 | * seccomp_can_sync_threads() to have returned success already | |
574 | * without dropping the locks. | |
575 | * | |
576 | */ | |
00a02d0c | 577 | static inline void seccomp_sync_threads(unsigned long flags) |
c2e1f2e3 KC |
578 | { |
579 | struct task_struct *thread, *caller; | |
580 | ||
581 | BUG_ON(!mutex_is_locked(¤t->signal->cred_guard_mutex)); | |
69f6a34b | 582 | assert_spin_locked(¤t->sighand->siglock); |
c2e1f2e3 KC |
583 | |
584 | /* Synchronize all threads. */ | |
585 | caller = current; | |
586 | for_each_thread(caller, thread) { | |
587 | /* Skip current, since it needs no changes. */ | |
588 | if (thread == caller) | |
589 | continue; | |
590 | ||
591 | /* Get a task reference for the new leaf node. */ | |
592 | get_seccomp_filter(caller); | |
99cdb8b9 | 593 | |
c2e1f2e3 KC |
594 | /* |
595 | * Drop the task reference to the shared ancestor since | |
596 | * current's path will hold a reference. (This also | |
597 | * allows a put before the assignment.) | |
598 | */ | |
99cdb8b9 CB |
599 | __seccomp_filter_release(thread->seccomp.filter); |
600 | ||
601 | /* Make our new filter tree visible. */ | |
c2e1f2e3 KC |
602 | smp_store_release(&thread->seccomp.filter, |
603 | caller->seccomp.filter); | |
c818c03b | 604 | atomic_set(&thread->seccomp.filter_count, |
b4d8a58f | 605 | atomic_read(&caller->seccomp.filter_count)); |
103502a3 JH |
606 | |
607 | /* | |
608 | * Don't let an unprivileged task work around | |
609 | * the no_new_privs restriction by creating | |
610 | * a thread that sets it up, enters seccomp, | |
611 | * then dies. | |
612 | */ | |
613 | if (task_no_new_privs(caller)) | |
614 | task_set_no_new_privs(thread); | |
615 | ||
c2e1f2e3 KC |
616 | /* |
617 | * Opt the other thread into seccomp if needed. | |
618 | * As threads are considered to be trust-realm | |
619 | * equivalent (see ptrace_may_access), it is safe to | |
620 | * allow one thread to transition the other. | |
621 | */ | |
103502a3 | 622 | if (thread->seccomp.mode == SECCOMP_MODE_DISABLED) |
00a02d0c KC |
623 | seccomp_assign_mode(thread, SECCOMP_MODE_FILTER, |
624 | flags); | |
c2e1f2e3 KC |
625 | } |
626 | } | |
627 | ||
e2cfabdf | 628 | /** |
c8bee430 | 629 | * seccomp_prepare_filter: Prepares a seccomp filter for use. |
e2cfabdf WD |
630 | * @fprog: BPF program to install |
631 | * | |
c8bee430 | 632 | * Returns filter on success or an ERR_PTR on failure. |
e2cfabdf | 633 | */ |
c8bee430 | 634 | static struct seccomp_filter *seccomp_prepare_filter(struct sock_fprog *fprog) |
e2cfabdf | 635 | { |
ac67eb2c DB |
636 | struct seccomp_filter *sfilter; |
637 | int ret; | |
8e01b51a YZ |
638 | const bool save_orig = |
639 | #if defined(CONFIG_CHECKPOINT_RESTORE) || defined(SECCOMP_ARCH_NATIVE) | |
640 | true; | |
641 | #else | |
642 | false; | |
643 | #endif | |
e2cfabdf WD |
644 | |
645 | if (fprog->len == 0 || fprog->len > BPF_MAXINSNS) | |
c8bee430 | 646 | return ERR_PTR(-EINVAL); |
d9e12f42 | 647 | |
c8bee430 | 648 | BUG_ON(INT_MAX / fprog->len < sizeof(struct sock_filter)); |
e2cfabdf WD |
649 | |
650 | /* | |
119ce5c8 | 651 | * Installing a seccomp filter requires that the task has |
e2cfabdf WD |
652 | * CAP_SYS_ADMIN in its namespace or be running with no_new_privs. |
653 | * This avoids scenarios where unprivileged tasks can affect the | |
654 | * behavior of privileged children. | |
655 | */ | |
1d4457f9 | 656 | if (!task_no_new_privs(current) && |
fb14528e | 657 | !ns_capable_noaudit(current_user_ns(), CAP_SYS_ADMIN)) |
c8bee430 | 658 | return ERR_PTR(-EACCES); |
e2cfabdf | 659 | |
bd4cf0ed | 660 | /* Allocate a new seccomp_filter */ |
ac67eb2c DB |
661 | sfilter = kzalloc(sizeof(*sfilter), GFP_KERNEL | __GFP_NOWARN); |
662 | if (!sfilter) | |
d9e12f42 | 663 | return ERR_PTR(-ENOMEM); |
ac67eb2c | 664 | |
6a21cc50 | 665 | mutex_init(&sfilter->notify_lock); |
ac67eb2c | 666 | ret = bpf_prog_create_from_user(&sfilter->prog, fprog, |
f8e529ed | 667 | seccomp_check_filter, save_orig); |
ac67eb2c DB |
668 | if (ret < 0) { |
669 | kfree(sfilter); | |
670 | return ERR_PTR(ret); | |
d9e12f42 | 671 | } |
bd4cf0ed | 672 | |
b707ddee | 673 | refcount_set(&sfilter->refs, 1); |
99cdb8b9 | 674 | refcount_set(&sfilter->users, 1); |
76194c4e | 675 | init_waitqueue_head(&sfilter->wqh); |
e2cfabdf | 676 | |
ac67eb2c | 677 | return sfilter; |
e2cfabdf WD |
678 | } |
679 | ||
680 | /** | |
c8bee430 | 681 | * seccomp_prepare_user_filter - prepares a user-supplied sock_fprog |
e2cfabdf WD |
682 | * @user_filter: pointer to the user data containing a sock_fprog. |
683 | * | |
684 | * Returns 0 on success and non-zero otherwise. | |
685 | */ | |
c8bee430 KC |
686 | static struct seccomp_filter * |
687 | seccomp_prepare_user_filter(const char __user *user_filter) | |
e2cfabdf WD |
688 | { |
689 | struct sock_fprog fprog; | |
c8bee430 | 690 | struct seccomp_filter *filter = ERR_PTR(-EFAULT); |
e2cfabdf WD |
691 | |
692 | #ifdef CONFIG_COMPAT | |
5c38065e | 693 | if (in_compat_syscall()) { |
e2cfabdf WD |
694 | struct compat_sock_fprog fprog32; |
695 | if (copy_from_user(&fprog32, user_filter, sizeof(fprog32))) | |
696 | goto out; | |
697 | fprog.len = fprog32.len; | |
698 | fprog.filter = compat_ptr(fprog32.filter); | |
699 | } else /* falls through to the if below. */ | |
700 | #endif | |
701 | if (copy_from_user(&fprog, user_filter, sizeof(fprog))) | |
702 | goto out; | |
c8bee430 | 703 | filter = seccomp_prepare_filter(&fprog); |
e2cfabdf | 704 | out: |
c8bee430 KC |
705 | return filter; |
706 | } | |
707 | ||
8e01b51a YZ |
708 | #ifdef SECCOMP_ARCH_NATIVE |
709 | /** | |
710 | * seccomp_is_const_allow - check if filter is constant allow with given data | |
711 | * @fprog: The BPF programs | |
712 | * @sd: The seccomp data to check against, only syscall number and arch | |
713 | * number are considered constant. | |
714 | */ | |
715 | static bool seccomp_is_const_allow(struct sock_fprog_kern *fprog, | |
716 | struct seccomp_data *sd) | |
717 | { | |
718 | unsigned int reg_value = 0; | |
719 | unsigned int pc; | |
720 | bool op_res; | |
721 | ||
722 | if (WARN_ON_ONCE(!fprog)) | |
723 | return false; | |
724 | ||
725 | for (pc = 0; pc < fprog->len; pc++) { | |
726 | struct sock_filter *insn = &fprog->filter[pc]; | |
727 | u16 code = insn->code; | |
728 | u32 k = insn->k; | |
729 | ||
730 | switch (code) { | |
731 | case BPF_LD | BPF_W | BPF_ABS: | |
732 | switch (k) { | |
733 | case offsetof(struct seccomp_data, nr): | |
734 | reg_value = sd->nr; | |
735 | break; | |
736 | case offsetof(struct seccomp_data, arch): | |
737 | reg_value = sd->arch; | |
738 | break; | |
739 | default: | |
740 | /* can't optimize (non-constant value load) */ | |
741 | return false; | |
742 | } | |
743 | break; | |
744 | case BPF_RET | BPF_K: | |
745 | /* reached return with constant values only, check allow */ | |
746 | return k == SECCOMP_RET_ALLOW; | |
747 | case BPF_JMP | BPF_JA: | |
748 | pc += insn->k; | |
749 | break; | |
750 | case BPF_JMP | BPF_JEQ | BPF_K: | |
751 | case BPF_JMP | BPF_JGE | BPF_K: | |
752 | case BPF_JMP | BPF_JGT | BPF_K: | |
753 | case BPF_JMP | BPF_JSET | BPF_K: | |
754 | switch (BPF_OP(code)) { | |
755 | case BPF_JEQ: | |
756 | op_res = reg_value == k; | |
757 | break; | |
758 | case BPF_JGE: | |
759 | op_res = reg_value >= k; | |
760 | break; | |
761 | case BPF_JGT: | |
762 | op_res = reg_value > k; | |
763 | break; | |
764 | case BPF_JSET: | |
765 | op_res = !!(reg_value & k); | |
766 | break; | |
767 | default: | |
768 | /* can't optimize (unknown jump) */ | |
769 | return false; | |
770 | } | |
771 | ||
772 | pc += op_res ? insn->jt : insn->jf; | |
773 | break; | |
774 | case BPF_ALU | BPF_AND | BPF_K: | |
775 | reg_value &= k; | |
776 | break; | |
777 | default: | |
778 | /* can't optimize (unknown insn) */ | |
779 | return false; | |
780 | } | |
781 | } | |
782 | ||
783 | /* ran off the end of the filter?! */ | |
784 | WARN_ON(1); | |
785 | return false; | |
786 | } | |
787 | ||
788 | static void seccomp_cache_prepare_bitmap(struct seccomp_filter *sfilter, | |
789 | void *bitmap, const void *bitmap_prev, | |
790 | size_t bitmap_size, int arch) | |
791 | { | |
792 | struct sock_fprog_kern *fprog = sfilter->prog->orig_prog; | |
793 | struct seccomp_data sd; | |
794 | int nr; | |
795 | ||
796 | if (bitmap_prev) { | |
797 | /* The new filter must be as restrictive as the last. */ | |
798 | bitmap_copy(bitmap, bitmap_prev, bitmap_size); | |
799 | } else { | |
800 | /* Before any filters, all syscalls are always allowed. */ | |
801 | bitmap_fill(bitmap, bitmap_size); | |
802 | } | |
803 | ||
804 | for (nr = 0; nr < bitmap_size; nr++) { | |
805 | /* No bitmap change: not a cacheable action. */ | |
806 | if (!test_bit(nr, bitmap)) | |
807 | continue; | |
808 | ||
809 | sd.nr = nr; | |
810 | sd.arch = arch; | |
811 | ||
812 | /* No bitmap change: continue to always allow. */ | |
813 | if (seccomp_is_const_allow(fprog, &sd)) | |
814 | continue; | |
815 | ||
816 | /* | |
817 | * Not a cacheable action: always run filters. | |
818 | * atomic clear_bit() not needed, filter not visible yet. | |
819 | */ | |
820 | __clear_bit(nr, bitmap); | |
821 | } | |
822 | } | |
823 | ||
824 | /** | |
a3fc712c | 825 | * seccomp_cache_prepare - emulate the filter to find cacheable syscalls |
8e01b51a YZ |
826 | * @sfilter: The seccomp filter |
827 | * | |
828 | * Returns 0 if successful or -errno if error occurred. | |
829 | */ | |
830 | static void seccomp_cache_prepare(struct seccomp_filter *sfilter) | |
831 | { | |
832 | struct action_cache *cache = &sfilter->cache; | |
833 | const struct action_cache *cache_prev = | |
834 | sfilter->prev ? &sfilter->prev->cache : NULL; | |
835 | ||
836 | seccomp_cache_prepare_bitmap(sfilter, cache->allow_native, | |
837 | cache_prev ? cache_prev->allow_native : NULL, | |
838 | SECCOMP_ARCH_NATIVE_NR, | |
839 | SECCOMP_ARCH_NATIVE); | |
840 | ||
841 | #ifdef SECCOMP_ARCH_COMPAT | |
842 | seccomp_cache_prepare_bitmap(sfilter, cache->allow_compat, | |
843 | cache_prev ? cache_prev->allow_compat : NULL, | |
844 | SECCOMP_ARCH_COMPAT_NR, | |
845 | SECCOMP_ARCH_COMPAT); | |
846 | #endif /* SECCOMP_ARCH_COMPAT */ | |
847 | } | |
848 | #endif /* SECCOMP_ARCH_NATIVE */ | |
849 | ||
c8bee430 KC |
850 | /** |
851 | * seccomp_attach_filter: validate and attach filter | |
852 | * @flags: flags to change filter behavior | |
853 | * @filter: seccomp filter to add to the current process | |
854 | * | |
dbd95212 KC |
855 | * Caller must be holding current->sighand->siglock lock. |
856 | * | |
7a0df7fb TA |
857 | * Returns 0 on success, -ve on error, or |
858 | * - in TSYNC mode: the pid of a thread which was either not in the correct | |
859 | * seccomp mode or did not have an ancestral seccomp filter | |
860 | * - in NEW_LISTENER mode: the fd of the new listener | |
c8bee430 KC |
861 | */ |
862 | static long seccomp_attach_filter(unsigned int flags, | |
863 | struct seccomp_filter *filter) | |
864 | { | |
865 | unsigned long total_insns; | |
866 | struct seccomp_filter *walker; | |
867 | ||
69f6a34b | 868 | assert_spin_locked(¤t->sighand->siglock); |
dbd95212 | 869 | |
c8bee430 KC |
870 | /* Validate resulting filter length. */ |
871 | total_insns = filter->prog->len; | |
872 | for (walker = current->seccomp.filter; walker; walker = walker->prev) | |
873 | total_insns += walker->prog->len + 4; /* 4 instr penalty */ | |
874 | if (total_insns > MAX_INSNS_PER_PATH) | |
875 | return -ENOMEM; | |
876 | ||
c2e1f2e3 KC |
877 | /* If thread sync has been requested, check that it is possible. */ |
878 | if (flags & SECCOMP_FILTER_FLAG_TSYNC) { | |
879 | int ret; | |
880 | ||
881 | ret = seccomp_can_sync_threads(); | |
51891498 TA |
882 | if (ret) { |
883 | if (flags & SECCOMP_FILTER_FLAG_TSYNC_ESRCH) | |
884 | return -ESRCH; | |
885 | else | |
886 | return ret; | |
887 | } | |
c2e1f2e3 KC |
888 | } |
889 | ||
e66a3997 TH |
890 | /* Set log flag, if present. */ |
891 | if (flags & SECCOMP_FILTER_FLAG_LOG) | |
892 | filter->log = true; | |
893 | ||
c8bee430 KC |
894 | /* |
895 | * If there is an existing filter, make it the prev and don't drop its | |
896 | * task reference. | |
897 | */ | |
898 | filter->prev = current->seccomp.filter; | |
8e01b51a | 899 | seccomp_cache_prepare(filter); |
c8bee430 | 900 | current->seccomp.filter = filter; |
c818c03b | 901 | atomic_inc(¤t->seccomp.filter_count); |
c8bee430 | 902 | |
c2e1f2e3 KC |
903 | /* Now that the new filter is in place, synchronize to all threads. */ |
904 | if (flags & SECCOMP_FILTER_FLAG_TSYNC) | |
00a02d0c | 905 | seccomp_sync_threads(flags); |
c2e1f2e3 | 906 | |
c8bee430 | 907 | return 0; |
e2cfabdf WD |
908 | } |
909 | ||
084f5601 | 910 | static void __get_seccomp_filter(struct seccomp_filter *filter) |
66a733ea | 911 | { |
b707ddee | 912 | refcount_inc(&filter->refs); |
66a733ea ON |
913 | } |
914 | ||
e2cfabdf WD |
915 | /* get_seccomp_filter - increments the reference count of the filter on @tsk */ |
916 | void get_seccomp_filter(struct task_struct *tsk) | |
917 | { | |
918 | struct seccomp_filter *orig = tsk->seccomp.filter; | |
919 | if (!orig) | |
920 | return; | |
66a733ea | 921 | __get_seccomp_filter(orig); |
99cdb8b9 | 922 | refcount_inc(&orig->users); |
e2cfabdf WD |
923 | } |
924 | ||
e2cfabdf | 925 | #endif /* CONFIG_SECCOMP_FILTER */ |
1da177e4 | 926 | |
0ddec0fc | 927 | /* For use with seccomp_actions_logged */ |
4d3b0b05 KC |
928 | #define SECCOMP_LOG_KILL_PROCESS (1 << 0) |
929 | #define SECCOMP_LOG_KILL_THREAD (1 << 1) | |
0ddec0fc TH |
930 | #define SECCOMP_LOG_TRAP (1 << 2) |
931 | #define SECCOMP_LOG_ERRNO (1 << 3) | |
932 | #define SECCOMP_LOG_TRACE (1 << 4) | |
59f5cf44 TH |
933 | #define SECCOMP_LOG_LOG (1 << 5) |
934 | #define SECCOMP_LOG_ALLOW (1 << 6) | |
6a21cc50 | 935 | #define SECCOMP_LOG_USER_NOTIF (1 << 7) |
0ddec0fc | 936 | |
4d3b0b05 KC |
937 | static u32 seccomp_actions_logged = SECCOMP_LOG_KILL_PROCESS | |
938 | SECCOMP_LOG_KILL_THREAD | | |
fd76875c KC |
939 | SECCOMP_LOG_TRAP | |
940 | SECCOMP_LOG_ERRNO | | |
6a21cc50 | 941 | SECCOMP_LOG_USER_NOTIF | |
fd76875c | 942 | SECCOMP_LOG_TRACE | |
59f5cf44 | 943 | SECCOMP_LOG_LOG; |
0ddec0fc | 944 | |
e66a3997 TH |
945 | static inline void seccomp_log(unsigned long syscall, long signr, u32 action, |
946 | bool requested) | |
0ddec0fc TH |
947 | { |
948 | bool log = false; | |
949 | ||
950 | switch (action) { | |
951 | case SECCOMP_RET_ALLOW: | |
e66a3997 | 952 | break; |
0ddec0fc | 953 | case SECCOMP_RET_TRAP: |
e66a3997 TH |
954 | log = requested && seccomp_actions_logged & SECCOMP_LOG_TRAP; |
955 | break; | |
0ddec0fc | 956 | case SECCOMP_RET_ERRNO: |
e66a3997 TH |
957 | log = requested && seccomp_actions_logged & SECCOMP_LOG_ERRNO; |
958 | break; | |
0ddec0fc | 959 | case SECCOMP_RET_TRACE: |
e66a3997 | 960 | log = requested && seccomp_actions_logged & SECCOMP_LOG_TRACE; |
0ddec0fc | 961 | break; |
6a21cc50 TA |
962 | case SECCOMP_RET_USER_NOTIF: |
963 | log = requested && seccomp_actions_logged & SECCOMP_LOG_USER_NOTIF; | |
964 | break; | |
59f5cf44 TH |
965 | case SECCOMP_RET_LOG: |
966 | log = seccomp_actions_logged & SECCOMP_LOG_LOG; | |
967 | break; | |
fd76875c | 968 | case SECCOMP_RET_KILL_THREAD: |
fd76875c | 969 | log = seccomp_actions_logged & SECCOMP_LOG_KILL_THREAD; |
4d3b0b05 KC |
970 | break; |
971 | case SECCOMP_RET_KILL_PROCESS: | |
972 | default: | |
973 | log = seccomp_actions_logged & SECCOMP_LOG_KILL_PROCESS; | |
0ddec0fc TH |
974 | } |
975 | ||
976 | /* | |
326bee02 TH |
977 | * Emit an audit message when the action is RET_KILL_*, RET_LOG, or the |
978 | * FILTER_FLAG_LOG bit was set. The admin has the ability to silence | |
979 | * any action from being logged by removing the action name from the | |
980 | * seccomp_actions_logged sysctl. | |
0ddec0fc | 981 | */ |
326bee02 TH |
982 | if (!log) |
983 | return; | |
0ddec0fc | 984 | |
326bee02 | 985 | audit_seccomp(syscall, signr, action); |
0ddec0fc TH |
986 | } |
987 | ||
1da177e4 LT |
988 | /* |
989 | * Secure computing mode 1 allows only read/write/exit/sigreturn. | |
990 | * To be fully secure this must be combined with rlimit | |
991 | * to limit the stack allocations too. | |
992 | */ | |
cb4253aa | 993 | static const int mode1_syscalls[] = { |
1da177e4 | 994 | __NR_seccomp_read, __NR_seccomp_write, __NR_seccomp_exit, __NR_seccomp_sigreturn, |
fe4bfff8 | 995 | -1, /* negative terminated */ |
1da177e4 LT |
996 | }; |
997 | ||
a4412fc9 | 998 | static void __secure_computing_strict(int this_syscall) |
1da177e4 | 999 | { |
fe4bfff8 | 1000 | const int *allowed_syscalls = mode1_syscalls; |
a4412fc9 | 1001 | #ifdef CONFIG_COMPAT |
5c38065e | 1002 | if (in_compat_syscall()) |
fe4bfff8 | 1003 | allowed_syscalls = get_compat_mode1_syscalls(); |
a4412fc9 AL |
1004 | #endif |
1005 | do { | |
fe4bfff8 | 1006 | if (*allowed_syscalls == this_syscall) |
a4412fc9 | 1007 | return; |
fe4bfff8 | 1008 | } while (*++allowed_syscalls != -1); |
a4412fc9 AL |
1009 | |
1010 | #ifdef SECCOMP_DEBUG | |
1011 | dump_stack(); | |
1012 | #endif | |
fd76875c | 1013 | seccomp_log(this_syscall, SIGKILL, SECCOMP_RET_KILL_THREAD, true); |
a4412fc9 AL |
1014 | do_exit(SIGKILL); |
1015 | } | |
1016 | ||
1017 | #ifndef CONFIG_HAVE_ARCH_SECCOMP_FILTER | |
1018 | void secure_computing_strict(int this_syscall) | |
1019 | { | |
1020 | int mode = current->seccomp.mode; | |
1021 | ||
97f2645f | 1022 | if (IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) && |
13c4a901 TA |
1023 | unlikely(current->ptrace & PT_SUSPEND_SECCOMP)) |
1024 | return; | |
1025 | ||
221272f9 | 1026 | if (mode == SECCOMP_MODE_DISABLED) |
a4412fc9 AL |
1027 | return; |
1028 | else if (mode == SECCOMP_MODE_STRICT) | |
1029 | __secure_computing_strict(this_syscall); | |
1030 | else | |
1031 | BUG(); | |
1032 | } | |
1033 | #else | |
13aa72f0 AL |
1034 | |
1035 | #ifdef CONFIG_SECCOMP_FILTER | |
6a21cc50 TA |
1036 | static u64 seccomp_next_notify_id(struct seccomp_filter *filter) |
1037 | { | |
1038 | /* | |
1039 | * Note: overflow is ok here, the id just needs to be unique per | |
1040 | * filter. | |
1041 | */ | |
1042 | lockdep_assert_held(&filter->notify_lock); | |
1043 | return filter->notif->next_id++; | |
1044 | } | |
1045 | ||
0ae71c77 | 1046 | static void seccomp_handle_addfd(struct seccomp_kaddfd *addfd, struct seccomp_knotif *n) |
7cf97b12 | 1047 | { |
0ae71c77 RC |
1048 | int fd; |
1049 | ||
7cf97b12 SD |
1050 | /* |
1051 | * Remove the notification, and reset the list pointers, indicating | |
1052 | * that it has been handled. | |
1053 | */ | |
1054 | list_del_init(&addfd->list); | |
42eb0d54 | 1055 | if (!addfd->setfd) |
0ae71c77 | 1056 | fd = receive_fd(addfd->file, addfd->flags); |
42eb0d54 | 1057 | else |
0ae71c77 RC |
1058 | fd = receive_fd_replace(addfd->fd, addfd->file, addfd->flags); |
1059 | addfd->ret = fd; | |
1060 | ||
1061 | if (addfd->ioctl_flags & SECCOMP_ADDFD_FLAG_SEND) { | |
1062 | /* If we fail reset and return an error to the notifier */ | |
1063 | if (fd < 0) { | |
1064 | n->state = SECCOMP_NOTIFY_SENT; | |
1065 | } else { | |
1066 | /* Return the FD we just added */ | |
1067 | n->flags = 0; | |
1068 | n->error = 0; | |
1069 | n->val = fd; | |
1070 | } | |
1071 | } | |
1072 | ||
1073 | /* | |
1074 | * Mark the notification as completed. From this point, addfd mem | |
1075 | * might be invalidated and we can't safely read it anymore. | |
1076 | */ | |
7cf97b12 SD |
1077 | complete(&addfd->completion); |
1078 | } | |
1079 | ||
fb3c5386 CB |
1080 | static int seccomp_do_user_notification(int this_syscall, |
1081 | struct seccomp_filter *match, | |
1082 | const struct seccomp_data *sd) | |
6a21cc50 TA |
1083 | { |
1084 | int err; | |
fb3c5386 | 1085 | u32 flags = 0; |
6a21cc50 TA |
1086 | long ret = 0; |
1087 | struct seccomp_knotif n = {}; | |
7cf97b12 | 1088 | struct seccomp_kaddfd *addfd, *tmp; |
6a21cc50 TA |
1089 | |
1090 | mutex_lock(&match->notify_lock); | |
1091 | err = -ENOSYS; | |
1092 | if (!match->notif) | |
1093 | goto out; | |
1094 | ||
1095 | n.task = current; | |
1096 | n.state = SECCOMP_NOTIFY_INIT; | |
1097 | n.data = sd; | |
1098 | n.id = seccomp_next_notify_id(match); | |
1099 | init_completion(&n.ready); | |
1100 | list_add(&n.list, &match->notif->notifications); | |
7cf97b12 | 1101 | INIT_LIST_HEAD(&n.addfd); |
6a21cc50 TA |
1102 | |
1103 | up(&match->notif->request); | |
76194c4e | 1104 | wake_up_poll(&match->wqh, EPOLLIN | EPOLLRDNORM); |
6a21cc50 TA |
1105 | |
1106 | /* | |
1107 | * This is where we wait for a reply from userspace. | |
1108 | */ | |
ddc47391 SD |
1109 | do { |
1110 | mutex_unlock(&match->notify_lock); | |
1111 | err = wait_for_completion_interruptible(&n.ready); | |
1112 | mutex_lock(&match->notify_lock); | |
1113 | if (err != 0) | |
1114 | goto interrupted; | |
1115 | ||
7cf97b12 SD |
1116 | addfd = list_first_entry_or_null(&n.addfd, |
1117 | struct seccomp_kaddfd, list); | |
ddc47391 SD |
1118 | /* Check if we were woken up by a addfd message */ |
1119 | if (addfd) | |
0ae71c77 | 1120 | seccomp_handle_addfd(addfd, &n); |
6a21cc50 | 1121 | |
ddc47391 SD |
1122 | } while (n.state != SECCOMP_NOTIFY_REPLIED); |
1123 | ||
1124 | ret = n.val; | |
1125 | err = n.error; | |
1126 | flags = n.flags; | |
1127 | ||
1128 | interrupted: | |
7cf97b12 SD |
1129 | /* If there were any pending addfd calls, clear them out */ |
1130 | list_for_each_entry_safe(addfd, tmp, &n.addfd, list) { | |
1131 | /* The process went away before we got a chance to handle it */ | |
1132 | addfd->ret = -ESRCH; | |
1133 | list_del_init(&addfd->list); | |
1134 | complete(&addfd->completion); | |
1135 | } | |
1136 | ||
6a21cc50 TA |
1137 | /* |
1138 | * Note that it's possible the listener died in between the time when | |
7cf97b12 | 1139 | * we were notified of a response (or a signal) and when we were able to |
6a21cc50 TA |
1140 | * re-acquire the lock, so only delete from the list if the |
1141 | * notification actually exists. | |
1142 | * | |
1143 | * Also note that this test is only valid because there's no way to | |
1144 | * *reattach* to a notifier right now. If one is added, we'll need to | |
1145 | * keep track of the notif itself and make sure they match here. | |
1146 | */ | |
1147 | if (match->notif) | |
1148 | list_del(&n.list); | |
1149 | out: | |
1150 | mutex_unlock(&match->notify_lock); | |
fb3c5386 CB |
1151 | |
1152 | /* Userspace requests to continue the syscall. */ | |
1153 | if (flags & SECCOMP_USER_NOTIF_FLAG_CONTINUE) | |
1154 | return 0; | |
1155 | ||
2d9ca267 | 1156 | syscall_set_return_value(current, current_pt_regs(), |
6a21cc50 | 1157 | err, ret); |
fb3c5386 | 1158 | return -1; |
6a21cc50 TA |
1159 | } |
1160 | ||
ce6526e8 KC |
1161 | static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd, |
1162 | const bool recheck_after_trace) | |
13aa72f0 AL |
1163 | { |
1164 | u32 filter_ret, action; | |
deb4de8b | 1165 | struct seccomp_filter *match = NULL; |
13aa72f0 | 1166 | int data; |
db511391 | 1167 | struct seccomp_data sd_local; |
1da177e4 | 1168 | |
3ba2530c KC |
1169 | /* |
1170 | * Make sure that any changes to mode from another thread have | |
23d67a54 | 1171 | * been seen after SYSCALL_WORK_SECCOMP was seen. |
3ba2530c | 1172 | */ |
a381b70a | 1173 | smp_rmb(); |
3ba2530c | 1174 | |
db511391 TA |
1175 | if (!sd) { |
1176 | populate_seccomp_data(&sd_local); | |
1177 | sd = &sd_local; | |
1178 | } | |
1179 | ||
deb4de8b | 1180 | filter_ret = seccomp_run_filters(sd, &match); |
13aa72f0 | 1181 | data = filter_ret & SECCOMP_RET_DATA; |
0466bdb9 | 1182 | action = filter_ret & SECCOMP_RET_ACTION_FULL; |
13aa72f0 AL |
1183 | |
1184 | switch (action) { | |
1185 | case SECCOMP_RET_ERRNO: | |
580c57f1 KC |
1186 | /* Set low-order bits as an errno, capped at MAX_ERRNO. */ |
1187 | if (data > MAX_ERRNO) | |
1188 | data = MAX_ERRNO; | |
2d9ca267 | 1189 | syscall_set_return_value(current, current_pt_regs(), |
13aa72f0 AL |
1190 | -data, 0); |
1191 | goto skip; | |
1192 | ||
1193 | case SECCOMP_RET_TRAP: | |
1194 | /* Show the handler the original registers. */ | |
2d9ca267 | 1195 | syscall_rollback(current, current_pt_regs()); |
13aa72f0 | 1196 | /* Let the filter pass back 16 bits of data. */ |
307d522f | 1197 | force_sig_seccomp(this_syscall, data, false); |
13aa72f0 AL |
1198 | goto skip; |
1199 | ||
1200 | case SECCOMP_RET_TRACE: | |
ce6526e8 KC |
1201 | /* We've been put in this state by the ptracer already. */ |
1202 | if (recheck_after_trace) | |
1203 | return 0; | |
1204 | ||
8112c4f1 KC |
1205 | /* ENOSYS these calls if there is no tracer attached. */ |
1206 | if (!ptrace_event_enabled(current, PTRACE_EVENT_SECCOMP)) { | |
1207 | syscall_set_return_value(current, | |
2d9ca267 | 1208 | current_pt_regs(), |
8112c4f1 KC |
1209 | -ENOSYS, 0); |
1210 | goto skip; | |
1211 | } | |
1212 | ||
1213 | /* Allow the BPF to provide the event message */ | |
1214 | ptrace_event(PTRACE_EVENT_SECCOMP, data); | |
1215 | /* | |
1216 | * The delivery of a fatal signal during event | |
485a252a KC |
1217 | * notification may silently skip tracer notification, |
1218 | * which could leave us with a potentially unmodified | |
1219 | * syscall that the tracer would have liked to have | |
1220 | * changed. Since the process is about to die, we just | |
1221 | * force the syscall to be skipped and let the signal | |
1222 | * kill the process and correctly handle any tracer exit | |
1223 | * notifications. | |
8112c4f1 KC |
1224 | */ |
1225 | if (fatal_signal_pending(current)) | |
485a252a | 1226 | goto skip; |
8112c4f1 | 1227 | /* Check if the tracer forced the syscall to be skipped. */ |
2d9ca267 | 1228 | this_syscall = syscall_get_nr(current, current_pt_regs()); |
8112c4f1 KC |
1229 | if (this_syscall < 0) |
1230 | goto skip; | |
1231 | ||
ce6526e8 KC |
1232 | /* |
1233 | * Recheck the syscall, since it may have changed. This | |
1234 | * intentionally uses a NULL struct seccomp_data to force | |
1235 | * a reload of all registers. This does not goto skip since | |
1236 | * a skip would have already been reported. | |
1237 | */ | |
1238 | if (__seccomp_filter(this_syscall, NULL, true)) | |
1239 | return -1; | |
1240 | ||
8112c4f1 | 1241 | return 0; |
13aa72f0 | 1242 | |
6a21cc50 | 1243 | case SECCOMP_RET_USER_NOTIF: |
fb3c5386 CB |
1244 | if (seccomp_do_user_notification(this_syscall, match, sd)) |
1245 | goto skip; | |
1246 | ||
1247 | return 0; | |
6a21cc50 | 1248 | |
59f5cf44 TH |
1249 | case SECCOMP_RET_LOG: |
1250 | seccomp_log(this_syscall, 0, action, true); | |
1251 | return 0; | |
1252 | ||
13aa72f0 | 1253 | case SECCOMP_RET_ALLOW: |
deb4de8b KC |
1254 | /* |
1255 | * Note that the "match" filter will always be NULL for | |
1256 | * this action since SECCOMP_RET_ALLOW is the starting | |
1257 | * state in seccomp_run_filters(). | |
1258 | */ | |
8112c4f1 | 1259 | return 0; |
13aa72f0 | 1260 | |
fd76875c | 1261 | case SECCOMP_RET_KILL_THREAD: |
4d3b0b05 | 1262 | case SECCOMP_RET_KILL_PROCESS: |
131b6351 | 1263 | default: |
e66a3997 | 1264 | seccomp_log(this_syscall, SIGSYS, action, true); |
d7276e32 | 1265 | /* Dump core only if this is the last remaining thread. */ |
4d671d92 | 1266 | if (action != SECCOMP_RET_KILL_THREAD || |
d21918e5 | 1267 | (atomic_read(¤t->signal->live) == 1)) { |
d7276e32 | 1268 | /* Show the original registers in the dump. */ |
2d9ca267 | 1269 | syscall_rollback(current, current_pt_regs()); |
307d522f EB |
1270 | /* Trigger a coredump with SIGSYS */ |
1271 | force_sig_seccomp(this_syscall, data, true); | |
1272 | } else { | |
4d3b0b05 | 1273 | do_exit(SIGSYS); |
307d522f EB |
1274 | } |
1275 | return -1; /* skip the syscall go directly to signal handling */ | |
13aa72f0 AL |
1276 | } |
1277 | ||
1278 | unreachable(); | |
1279 | ||
1280 | skip: | |
e66a3997 | 1281 | seccomp_log(this_syscall, 0, action, match ? match->log : false); |
8112c4f1 KC |
1282 | return -1; |
1283 | } | |
1284 | #else | |
ce6526e8 KC |
1285 | static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd, |
1286 | const bool recheck_after_trace) | |
8112c4f1 KC |
1287 | { |
1288 | BUG(); | |
04b38d01 PC |
1289 | |
1290 | return -1; | |
13aa72f0 | 1291 | } |
1da177e4 | 1292 | #endif |
13aa72f0 | 1293 | |
8112c4f1 | 1294 | int __secure_computing(const struct seccomp_data *sd) |
13aa72f0 AL |
1295 | { |
1296 | int mode = current->seccomp.mode; | |
8112c4f1 | 1297 | int this_syscall; |
13aa72f0 | 1298 | |
97f2645f | 1299 | if (IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) && |
13c4a901 | 1300 | unlikely(current->ptrace & PT_SUSPEND_SECCOMP)) |
8112c4f1 KC |
1301 | return 0; |
1302 | ||
1303 | this_syscall = sd ? sd->nr : | |
2d9ca267 | 1304 | syscall_get_nr(current, current_pt_regs()); |
13c4a901 | 1305 | |
13aa72f0 | 1306 | switch (mode) { |
e2cfabdf | 1307 | case SECCOMP_MODE_STRICT: |
13aa72f0 | 1308 | __secure_computing_strict(this_syscall); /* may call do_exit */ |
8112c4f1 | 1309 | return 0; |
13aa72f0 | 1310 | case SECCOMP_MODE_FILTER: |
ce6526e8 | 1311 | return __seccomp_filter(this_syscall, sd, false); |
1da177e4 LT |
1312 | default: |
1313 | BUG(); | |
1314 | } | |
13aa72f0 | 1315 | } |
a4412fc9 | 1316 | #endif /* CONFIG_HAVE_ARCH_SECCOMP_FILTER */ |
1d9d02fe AA |
1317 | |
1318 | long prctl_get_seccomp(void) | |
1319 | { | |
1320 | return current->seccomp.mode; | |
1321 | } | |
1322 | ||
e2cfabdf | 1323 | /** |
3b23dd12 | 1324 | * seccomp_set_mode_strict: internal function for setting strict seccomp |
e2cfabdf WD |
1325 | * |
1326 | * Once current->seccomp.mode is non-zero, it may not be changed. | |
1327 | * | |
1328 | * Returns 0 on success or -EINVAL on failure. | |
1329 | */ | |
3b23dd12 | 1330 | static long seccomp_set_mode_strict(void) |
1d9d02fe | 1331 | { |
3b23dd12 | 1332 | const unsigned long seccomp_mode = SECCOMP_MODE_STRICT; |
e2cfabdf | 1333 | long ret = -EINVAL; |
1d9d02fe | 1334 | |
dbd95212 KC |
1335 | spin_lock_irq(¤t->sighand->siglock); |
1336 | ||
1f41b450 | 1337 | if (!seccomp_may_assign_mode(seccomp_mode)) |
1d9d02fe AA |
1338 | goto out; |
1339 | ||
cf99abac | 1340 | #ifdef TIF_NOTSC |
3b23dd12 | 1341 | disable_TSC(); |
cf99abac | 1342 | #endif |
00a02d0c | 1343 | seccomp_assign_mode(current, seccomp_mode, 0); |
3b23dd12 KC |
1344 | ret = 0; |
1345 | ||
1346 | out: | |
dbd95212 | 1347 | spin_unlock_irq(¤t->sighand->siglock); |
3b23dd12 KC |
1348 | |
1349 | return ret; | |
1350 | } | |
1351 | ||
e2cfabdf | 1352 | #ifdef CONFIG_SECCOMP_FILTER |
e8393179 TA |
1353 | static void seccomp_notify_free(struct seccomp_filter *filter) |
1354 | { | |
1355 | kfree(filter->notif); | |
1356 | filter->notif = NULL; | |
1357 | } | |
1358 | ||
a566a901 | 1359 | static void seccomp_notify_detach(struct seccomp_filter *filter) |
6a21cc50 | 1360 | { |
6a21cc50 TA |
1361 | struct seccomp_knotif *knotif; |
1362 | ||
a811dc61 | 1363 | if (!filter) |
a566a901 | 1364 | return; |
a811dc61 | 1365 | |
6a21cc50 TA |
1366 | mutex_lock(&filter->notify_lock); |
1367 | ||
1368 | /* | |
1369 | * If this file is being closed because e.g. the task who owned it | |
1370 | * died, let's wake everyone up who was waiting on us. | |
1371 | */ | |
1372 | list_for_each_entry(knotif, &filter->notif->notifications, list) { | |
1373 | if (knotif->state == SECCOMP_NOTIFY_REPLIED) | |
1374 | continue; | |
1375 | ||
1376 | knotif->state = SECCOMP_NOTIFY_REPLIED; | |
1377 | knotif->error = -ENOSYS; | |
1378 | knotif->val = 0; | |
1379 | ||
7cf97b12 SD |
1380 | /* |
1381 | * We do not need to wake up any pending addfd messages, as | |
1382 | * the notifier will do that for us, as this just looks | |
1383 | * like a standard reply. | |
1384 | */ | |
6a21cc50 TA |
1385 | complete(&knotif->ready); |
1386 | } | |
1387 | ||
e8393179 | 1388 | seccomp_notify_free(filter); |
6a21cc50 | 1389 | mutex_unlock(&filter->notify_lock); |
a566a901 TA |
1390 | } |
1391 | ||
1392 | static int seccomp_notify_release(struct inode *inode, struct file *file) | |
1393 | { | |
1394 | struct seccomp_filter *filter = file->private_data; | |
1395 | ||
1396 | seccomp_notify_detach(filter); | |
6a21cc50 TA |
1397 | __put_seccomp_filter(filter); |
1398 | return 0; | |
1399 | } | |
1400 | ||
9f87dcf1 SD |
1401 | /* must be called with notif_lock held */ |
1402 | static inline struct seccomp_knotif * | |
1403 | find_notification(struct seccomp_filter *filter, u64 id) | |
1404 | { | |
1405 | struct seccomp_knotif *cur; | |
1406 | ||
1407 | lockdep_assert_held(&filter->notify_lock); | |
1408 | ||
1409 | list_for_each_entry(cur, &filter->notif->notifications, list) { | |
1410 | if (cur->id == id) | |
1411 | return cur; | |
1412 | } | |
1413 | ||
1414 | return NULL; | |
1415 | } | |
1416 | ||
1417 | ||
6a21cc50 TA |
1418 | static long seccomp_notify_recv(struct seccomp_filter *filter, |
1419 | void __user *buf) | |
1420 | { | |
1421 | struct seccomp_knotif *knotif = NULL, *cur; | |
1422 | struct seccomp_notif unotif; | |
1423 | ssize_t ret; | |
1424 | ||
2882d53c SD |
1425 | /* Verify that we're not given garbage to keep struct extensible. */ |
1426 | ret = check_zeroed_user(buf, sizeof(unotif)); | |
1427 | if (ret < 0) | |
1428 | return ret; | |
1429 | if (!ret) | |
1430 | return -EINVAL; | |
1431 | ||
6a21cc50 TA |
1432 | memset(&unotif, 0, sizeof(unotif)); |
1433 | ||
1434 | ret = down_interruptible(&filter->notif->request); | |
1435 | if (ret < 0) | |
1436 | return ret; | |
1437 | ||
1438 | mutex_lock(&filter->notify_lock); | |
1439 | list_for_each_entry(cur, &filter->notif->notifications, list) { | |
1440 | if (cur->state == SECCOMP_NOTIFY_INIT) { | |
1441 | knotif = cur; | |
1442 | break; | |
1443 | } | |
1444 | } | |
1445 | ||
1446 | /* | |
1447 | * If we didn't find a notification, it could be that the task was | |
1448 | * interrupted by a fatal signal between the time we were woken and | |
1449 | * when we were able to acquire the rw lock. | |
1450 | */ | |
1451 | if (!knotif) { | |
1452 | ret = -ENOENT; | |
1453 | goto out; | |
1454 | } | |
1455 | ||
1456 | unotif.id = knotif->id; | |
1457 | unotif.pid = task_pid_vnr(knotif->task); | |
1458 | unotif.data = *(knotif->data); | |
1459 | ||
1460 | knotif->state = SECCOMP_NOTIFY_SENT; | |
76194c4e | 1461 | wake_up_poll(&filter->wqh, EPOLLOUT | EPOLLWRNORM); |
6a21cc50 TA |
1462 | ret = 0; |
1463 | out: | |
1464 | mutex_unlock(&filter->notify_lock); | |
1465 | ||
1466 | if (ret == 0 && copy_to_user(buf, &unotif, sizeof(unotif))) { | |
1467 | ret = -EFAULT; | |
1468 | ||
1469 | /* | |
1470 | * Userspace screwed up. To make sure that we keep this | |
1471 | * notification alive, let's reset it back to INIT. It | |
1472 | * may have died when we released the lock, so we need to make | |
1473 | * sure it's still around. | |
1474 | */ | |
6a21cc50 | 1475 | mutex_lock(&filter->notify_lock); |
9f87dcf1 | 1476 | knotif = find_notification(filter, unotif.id); |
6a21cc50 TA |
1477 | if (knotif) { |
1478 | knotif->state = SECCOMP_NOTIFY_INIT; | |
1479 | up(&filter->notif->request); | |
1480 | } | |
1481 | mutex_unlock(&filter->notify_lock); | |
1482 | } | |
1483 | ||
1484 | return ret; | |
1485 | } | |
1486 | ||
1487 | static long seccomp_notify_send(struct seccomp_filter *filter, | |
1488 | void __user *buf) | |
1489 | { | |
1490 | struct seccomp_notif_resp resp = {}; | |
9f87dcf1 | 1491 | struct seccomp_knotif *knotif; |
6a21cc50 TA |
1492 | long ret; |
1493 | ||
1494 | if (copy_from_user(&resp, buf, sizeof(resp))) | |
1495 | return -EFAULT; | |
1496 | ||
fb3c5386 CB |
1497 | if (resp.flags & ~SECCOMP_USER_NOTIF_FLAG_CONTINUE) |
1498 | return -EINVAL; | |
1499 | ||
1500 | if ((resp.flags & SECCOMP_USER_NOTIF_FLAG_CONTINUE) && | |
1501 | (resp.error || resp.val)) | |
6a21cc50 TA |
1502 | return -EINVAL; |
1503 | ||
1504 | ret = mutex_lock_interruptible(&filter->notify_lock); | |
1505 | if (ret < 0) | |
1506 | return ret; | |
1507 | ||
9f87dcf1 | 1508 | knotif = find_notification(filter, resp.id); |
6a21cc50 TA |
1509 | if (!knotif) { |
1510 | ret = -ENOENT; | |
1511 | goto out; | |
1512 | } | |
1513 | ||
1514 | /* Allow exactly one reply. */ | |
1515 | if (knotif->state != SECCOMP_NOTIFY_SENT) { | |
1516 | ret = -EINPROGRESS; | |
1517 | goto out; | |
1518 | } | |
1519 | ||
1520 | ret = 0; | |
1521 | knotif->state = SECCOMP_NOTIFY_REPLIED; | |
1522 | knotif->error = resp.error; | |
1523 | knotif->val = resp.val; | |
fb3c5386 | 1524 | knotif->flags = resp.flags; |
6a21cc50 TA |
1525 | complete(&knotif->ready); |
1526 | out: | |
1527 | mutex_unlock(&filter->notify_lock); | |
1528 | return ret; | |
1529 | } | |
1530 | ||
1531 | static long seccomp_notify_id_valid(struct seccomp_filter *filter, | |
1532 | void __user *buf) | |
1533 | { | |
9f87dcf1 | 1534 | struct seccomp_knotif *knotif; |
6a21cc50 TA |
1535 | u64 id; |
1536 | long ret; | |
1537 | ||
1538 | if (copy_from_user(&id, buf, sizeof(id))) | |
1539 | return -EFAULT; | |
1540 | ||
1541 | ret = mutex_lock_interruptible(&filter->notify_lock); | |
1542 | if (ret < 0) | |
1543 | return ret; | |
1544 | ||
9f87dcf1 SD |
1545 | knotif = find_notification(filter, id); |
1546 | if (knotif && knotif->state == SECCOMP_NOTIFY_SENT) | |
1547 | ret = 0; | |
1548 | else | |
1549 | ret = -ENOENT; | |
6a21cc50 | 1550 | |
6a21cc50 TA |
1551 | mutex_unlock(&filter->notify_lock); |
1552 | return ret; | |
1553 | } | |
1554 | ||
7cf97b12 SD |
1555 | static long seccomp_notify_addfd(struct seccomp_filter *filter, |
1556 | struct seccomp_notif_addfd __user *uaddfd, | |
1557 | unsigned int size) | |
1558 | { | |
1559 | struct seccomp_notif_addfd addfd; | |
1560 | struct seccomp_knotif *knotif; | |
1561 | struct seccomp_kaddfd kaddfd; | |
1562 | int ret; | |
1563 | ||
1564 | BUILD_BUG_ON(sizeof(addfd) < SECCOMP_NOTIFY_ADDFD_SIZE_VER0); | |
1565 | BUILD_BUG_ON(sizeof(addfd) != SECCOMP_NOTIFY_ADDFD_SIZE_LATEST); | |
1566 | ||
1567 | if (size < SECCOMP_NOTIFY_ADDFD_SIZE_VER0 || size >= PAGE_SIZE) | |
1568 | return -EINVAL; | |
1569 | ||
1570 | ret = copy_struct_from_user(&addfd, sizeof(addfd), uaddfd, size); | |
1571 | if (ret) | |
1572 | return ret; | |
1573 | ||
1574 | if (addfd.newfd_flags & ~O_CLOEXEC) | |
1575 | return -EINVAL; | |
1576 | ||
0ae71c77 | 1577 | if (addfd.flags & ~(SECCOMP_ADDFD_FLAG_SETFD | SECCOMP_ADDFD_FLAG_SEND)) |
7cf97b12 SD |
1578 | return -EINVAL; |
1579 | ||
1580 | if (addfd.newfd && !(addfd.flags & SECCOMP_ADDFD_FLAG_SETFD)) | |
1581 | return -EINVAL; | |
1582 | ||
1583 | kaddfd.file = fget(addfd.srcfd); | |
1584 | if (!kaddfd.file) | |
1585 | return -EBADF; | |
1586 | ||
0ae71c77 | 1587 | kaddfd.ioctl_flags = addfd.flags; |
7cf97b12 | 1588 | kaddfd.flags = addfd.newfd_flags; |
42eb0d54 CH |
1589 | kaddfd.setfd = addfd.flags & SECCOMP_ADDFD_FLAG_SETFD; |
1590 | kaddfd.fd = addfd.newfd; | |
7cf97b12 SD |
1591 | init_completion(&kaddfd.completion); |
1592 | ||
1593 | ret = mutex_lock_interruptible(&filter->notify_lock); | |
1594 | if (ret < 0) | |
1595 | goto out; | |
1596 | ||
1597 | knotif = find_notification(filter, addfd.id); | |
1598 | if (!knotif) { | |
1599 | ret = -ENOENT; | |
1600 | goto out_unlock; | |
1601 | } | |
1602 | ||
1603 | /* | |
1604 | * We do not want to allow for FD injection to occur before the | |
1605 | * notification has been picked up by a userspace handler, or after | |
1606 | * the notification has been replied to. | |
1607 | */ | |
1608 | if (knotif->state != SECCOMP_NOTIFY_SENT) { | |
1609 | ret = -EINPROGRESS; | |
1610 | goto out_unlock; | |
1611 | } | |
1612 | ||
0ae71c77 RC |
1613 | if (addfd.flags & SECCOMP_ADDFD_FLAG_SEND) { |
1614 | /* | |
1615 | * Disallow queuing an atomic addfd + send reply while there are | |
1616 | * some addfd requests still to process. | |
1617 | * | |
1618 | * There is no clear reason to support it and allows us to keep | |
1619 | * the loop on the other side straight-forward. | |
1620 | */ | |
1621 | if (!list_empty(&knotif->addfd)) { | |
1622 | ret = -EBUSY; | |
1623 | goto out_unlock; | |
1624 | } | |
1625 | ||
1626 | /* Allow exactly only one reply */ | |
1627 | knotif->state = SECCOMP_NOTIFY_REPLIED; | |
1628 | } | |
1629 | ||
7cf97b12 SD |
1630 | list_add(&kaddfd.list, &knotif->addfd); |
1631 | complete(&knotif->ready); | |
1632 | mutex_unlock(&filter->notify_lock); | |
1633 | ||
1634 | /* Now we wait for it to be processed or be interrupted */ | |
1635 | ret = wait_for_completion_interruptible(&kaddfd.completion); | |
1636 | if (ret == 0) { | |
1637 | /* | |
1638 | * We had a successful completion. The other side has already | |
1639 | * removed us from the addfd queue, and | |
1640 | * wait_for_completion_interruptible has a memory barrier upon | |
1641 | * success that lets us read this value directly without | |
1642 | * locking. | |
1643 | */ | |
1644 | ret = kaddfd.ret; | |
1645 | goto out; | |
1646 | } | |
1647 | ||
1648 | mutex_lock(&filter->notify_lock); | |
1649 | /* | |
1650 | * Even though we were woken up by a signal and not a successful | |
1651 | * completion, a completion may have happened in the mean time. | |
1652 | * | |
1653 | * We need to check again if the addfd request has been handled, | |
1654 | * and if not, we will remove it from the queue. | |
1655 | */ | |
1656 | if (list_empty(&kaddfd.list)) | |
1657 | ret = kaddfd.ret; | |
1658 | else | |
1659 | list_del(&kaddfd.list); | |
1660 | ||
1661 | out_unlock: | |
1662 | mutex_unlock(&filter->notify_lock); | |
1663 | out: | |
1664 | fput(kaddfd.file); | |
1665 | ||
1666 | return ret; | |
1667 | } | |
1668 | ||
6a21cc50 TA |
1669 | static long seccomp_notify_ioctl(struct file *file, unsigned int cmd, |
1670 | unsigned long arg) | |
1671 | { | |
1672 | struct seccomp_filter *filter = file->private_data; | |
1673 | void __user *buf = (void __user *)arg; | |
1674 | ||
7cf97b12 | 1675 | /* Fixed-size ioctls */ |
6a21cc50 TA |
1676 | switch (cmd) { |
1677 | case SECCOMP_IOCTL_NOTIF_RECV: | |
1678 | return seccomp_notify_recv(filter, buf); | |
1679 | case SECCOMP_IOCTL_NOTIF_SEND: | |
1680 | return seccomp_notify_send(filter, buf); | |
47e33c05 | 1681 | case SECCOMP_IOCTL_NOTIF_ID_VALID_WRONG_DIR: |
6a21cc50 TA |
1682 | case SECCOMP_IOCTL_NOTIF_ID_VALID: |
1683 | return seccomp_notify_id_valid(filter, buf); | |
7cf97b12 SD |
1684 | } |
1685 | ||
1686 | /* Extensible Argument ioctls */ | |
1687 | #define EA_IOCTL(cmd) ((cmd) & ~(IOC_INOUT | IOCSIZE_MASK)) | |
1688 | switch (EA_IOCTL(cmd)) { | |
1689 | case EA_IOCTL(SECCOMP_IOCTL_NOTIF_ADDFD): | |
1690 | return seccomp_notify_addfd(filter, buf, _IOC_SIZE(cmd)); | |
6a21cc50 TA |
1691 | default: |
1692 | return -EINVAL; | |
1693 | } | |
1694 | } | |
1695 | ||
1696 | static __poll_t seccomp_notify_poll(struct file *file, | |
1697 | struct poll_table_struct *poll_tab) | |
1698 | { | |
1699 | struct seccomp_filter *filter = file->private_data; | |
1700 | __poll_t ret = 0; | |
1701 | struct seccomp_knotif *cur; | |
1702 | ||
76194c4e | 1703 | poll_wait(file, &filter->wqh, poll_tab); |
6a21cc50 | 1704 | |
319deec7 | 1705 | if (mutex_lock_interruptible(&filter->notify_lock) < 0) |
6a21cc50 TA |
1706 | return EPOLLERR; |
1707 | ||
1708 | list_for_each_entry(cur, &filter->notif->notifications, list) { | |
1709 | if (cur->state == SECCOMP_NOTIFY_INIT) | |
1710 | ret |= EPOLLIN | EPOLLRDNORM; | |
1711 | if (cur->state == SECCOMP_NOTIFY_SENT) | |
1712 | ret |= EPOLLOUT | EPOLLWRNORM; | |
1713 | if ((ret & EPOLLIN) && (ret & EPOLLOUT)) | |
1714 | break; | |
1715 | } | |
1716 | ||
1717 | mutex_unlock(&filter->notify_lock); | |
1718 | ||
99cdb8b9 CB |
1719 | if (refcount_read(&filter->users) == 0) |
1720 | ret |= EPOLLHUP; | |
1721 | ||
6a21cc50 TA |
1722 | return ret; |
1723 | } | |
1724 | ||
1725 | static const struct file_operations seccomp_notify_ops = { | |
1726 | .poll = seccomp_notify_poll, | |
1727 | .release = seccomp_notify_release, | |
1728 | .unlocked_ioctl = seccomp_notify_ioctl, | |
3db81afd | 1729 | .compat_ioctl = seccomp_notify_ioctl, |
6a21cc50 TA |
1730 | }; |
1731 | ||
1732 | static struct file *init_listener(struct seccomp_filter *filter) | |
1733 | { | |
dfe719fe | 1734 | struct file *ret; |
6a21cc50 TA |
1735 | |
1736 | ret = ERR_PTR(-ENOMEM); | |
1737 | filter->notif = kzalloc(sizeof(*(filter->notif)), GFP_KERNEL); | |
1738 | if (!filter->notif) | |
1739 | goto out; | |
1740 | ||
1741 | sema_init(&filter->notif->request, 0); | |
1742 | filter->notif->next_id = get_random_u64(); | |
1743 | INIT_LIST_HEAD(&filter->notif->notifications); | |
6a21cc50 TA |
1744 | |
1745 | ret = anon_inode_getfile("seccomp notify", &seccomp_notify_ops, | |
1746 | filter, O_RDWR); | |
1747 | if (IS_ERR(ret)) | |
1748 | goto out_notif; | |
1749 | ||
1750 | /* The file has a reference to it now */ | |
1751 | __get_seccomp_filter(filter); | |
1752 | ||
1753 | out_notif: | |
1754 | if (IS_ERR(ret)) | |
e8393179 | 1755 | seccomp_notify_free(filter); |
6a21cc50 TA |
1756 | out: |
1757 | return ret; | |
1758 | } | |
1759 | ||
dfe719fe JH |
1760 | /* |
1761 | * Does @new_child have a listener while an ancestor also has a listener? | |
1762 | * If so, we'll want to reject this filter. | |
1763 | * This only has to be tested for the current process, even in the TSYNC case, | |
1764 | * because TSYNC installs @child with the same parent on all threads. | |
1765 | * Note that @new_child is not hooked up to its parent at this point yet, so | |
1766 | * we use current->seccomp.filter. | |
1767 | */ | |
1768 | static bool has_duplicate_listener(struct seccomp_filter *new_child) | |
1769 | { | |
1770 | struct seccomp_filter *cur; | |
1771 | ||
1772 | /* must be protected against concurrent TSYNC */ | |
1773 | lockdep_assert_held(¤t->sighand->siglock); | |
1774 | ||
1775 | if (!new_child->notif) | |
1776 | return false; | |
1777 | for (cur = current->seccomp.filter; cur; cur = cur->prev) { | |
1778 | if (cur->notif) | |
1779 | return true; | |
1780 | } | |
1781 | ||
1782 | return false; | |
1783 | } | |
1784 | ||
3b23dd12 KC |
1785 | /** |
1786 | * seccomp_set_mode_filter: internal function for setting seccomp filter | |
48dc92b9 | 1787 | * @flags: flags to change filter behavior |
3b23dd12 KC |
1788 | * @filter: struct sock_fprog containing filter |
1789 | * | |
1790 | * This function may be called repeatedly to install additional filters. | |
1791 | * Every filter successfully installed will be evaluated (in reverse order) | |
1792 | * for each system call the task makes. | |
1793 | * | |
1794 | * Once current->seccomp.mode is non-zero, it may not be changed. | |
1795 | * | |
1796 | * Returns 0 on success or -EINVAL on failure. | |
1797 | */ | |
48dc92b9 KC |
1798 | static long seccomp_set_mode_filter(unsigned int flags, |
1799 | const char __user *filter) | |
3b23dd12 KC |
1800 | { |
1801 | const unsigned long seccomp_mode = SECCOMP_MODE_FILTER; | |
c8bee430 | 1802 | struct seccomp_filter *prepared = NULL; |
3b23dd12 | 1803 | long ret = -EINVAL; |
6a21cc50 TA |
1804 | int listener = -1; |
1805 | struct file *listener_f = NULL; | |
3b23dd12 | 1806 | |
48dc92b9 | 1807 | /* Validate flags. */ |
c2e1f2e3 | 1808 | if (flags & ~SECCOMP_FILTER_FLAG_MASK) |
dbd95212 | 1809 | return -EINVAL; |
48dc92b9 | 1810 | |
7a0df7fb TA |
1811 | /* |
1812 | * In the successful case, NEW_LISTENER returns the new listener fd. | |
1813 | * But in the failure case, TSYNC returns the thread that died. If you | |
1814 | * combine these two flags, there's no way to tell whether something | |
51891498 TA |
1815 | * succeeded or failed. So, let's disallow this combination if the user |
1816 | * has not explicitly requested no errors from TSYNC. | |
7a0df7fb TA |
1817 | */ |
1818 | if ((flags & SECCOMP_FILTER_FLAG_TSYNC) && | |
51891498 TA |
1819 | (flags & SECCOMP_FILTER_FLAG_NEW_LISTENER) && |
1820 | ((flags & SECCOMP_FILTER_FLAG_TSYNC_ESRCH) == 0)) | |
7a0df7fb TA |
1821 | return -EINVAL; |
1822 | ||
c8bee430 KC |
1823 | /* Prepare the new filter before holding any locks. */ |
1824 | prepared = seccomp_prepare_user_filter(filter); | |
1825 | if (IS_ERR(prepared)) | |
1826 | return PTR_ERR(prepared); | |
1827 | ||
6a21cc50 TA |
1828 | if (flags & SECCOMP_FILTER_FLAG_NEW_LISTENER) { |
1829 | listener = get_unused_fd_flags(O_CLOEXEC); | |
1830 | if (listener < 0) { | |
1831 | ret = listener; | |
1832 | goto out_free; | |
1833 | } | |
1834 | ||
1835 | listener_f = init_listener(prepared); | |
1836 | if (IS_ERR(listener_f)) { | |
1837 | put_unused_fd(listener); | |
1838 | ret = PTR_ERR(listener_f); | |
1839 | goto out_free; | |
1840 | } | |
1841 | } | |
1842 | ||
c2e1f2e3 KC |
1843 | /* |
1844 | * Make sure we cannot change seccomp or nnp state via TSYNC | |
1845 | * while another thread is in the middle of calling exec. | |
1846 | */ | |
1847 | if (flags & SECCOMP_FILTER_FLAG_TSYNC && | |
1848 | mutex_lock_killable(¤t->signal->cred_guard_mutex)) | |
6a21cc50 | 1849 | goto out_put_fd; |
c2e1f2e3 | 1850 | |
dbd95212 KC |
1851 | spin_lock_irq(¤t->sighand->siglock); |
1852 | ||
3b23dd12 KC |
1853 | if (!seccomp_may_assign_mode(seccomp_mode)) |
1854 | goto out; | |
1855 | ||
dfe719fe JH |
1856 | if (has_duplicate_listener(prepared)) { |
1857 | ret = -EBUSY; | |
1858 | goto out; | |
1859 | } | |
1860 | ||
c8bee430 | 1861 | ret = seccomp_attach_filter(flags, prepared); |
3b23dd12 | 1862 | if (ret) |
e2cfabdf | 1863 | goto out; |
c8bee430 KC |
1864 | /* Do not free the successfully attached filter. */ |
1865 | prepared = NULL; | |
1d9d02fe | 1866 | |
00a02d0c | 1867 | seccomp_assign_mode(current, seccomp_mode, flags); |
e2cfabdf | 1868 | out: |
dbd95212 | 1869 | spin_unlock_irq(¤t->sighand->siglock); |
c2e1f2e3 KC |
1870 | if (flags & SECCOMP_FILTER_FLAG_TSYNC) |
1871 | mutex_unlock(¤t->signal->cred_guard_mutex); | |
6a21cc50 TA |
1872 | out_put_fd: |
1873 | if (flags & SECCOMP_FILTER_FLAG_NEW_LISTENER) { | |
7a0df7fb | 1874 | if (ret) { |
a811dc61 | 1875 | listener_f->private_data = NULL; |
6a21cc50 TA |
1876 | fput(listener_f); |
1877 | put_unused_fd(listener); | |
a566a901 | 1878 | seccomp_notify_detach(prepared); |
6a21cc50 TA |
1879 | } else { |
1880 | fd_install(listener, listener_f); | |
1881 | ret = listener; | |
1882 | } | |
1883 | } | |
c2e1f2e3 | 1884 | out_free: |
c8bee430 | 1885 | seccomp_filter_free(prepared); |
1d9d02fe AA |
1886 | return ret; |
1887 | } | |
3b23dd12 | 1888 | #else |
48dc92b9 KC |
1889 | static inline long seccomp_set_mode_filter(unsigned int flags, |
1890 | const char __user *filter) | |
3b23dd12 KC |
1891 | { |
1892 | return -EINVAL; | |
1893 | } | |
1894 | #endif | |
d78ab02c | 1895 | |
d612b1fd TH |
1896 | static long seccomp_get_action_avail(const char __user *uaction) |
1897 | { | |
1898 | u32 action; | |
1899 | ||
1900 | if (copy_from_user(&action, uaction, sizeof(action))) | |
1901 | return -EFAULT; | |
1902 | ||
1903 | switch (action) { | |
0466bdb9 | 1904 | case SECCOMP_RET_KILL_PROCESS: |
fd76875c | 1905 | case SECCOMP_RET_KILL_THREAD: |
d612b1fd TH |
1906 | case SECCOMP_RET_TRAP: |
1907 | case SECCOMP_RET_ERRNO: | |
6a21cc50 | 1908 | case SECCOMP_RET_USER_NOTIF: |
d612b1fd | 1909 | case SECCOMP_RET_TRACE: |
59f5cf44 | 1910 | case SECCOMP_RET_LOG: |
d612b1fd TH |
1911 | case SECCOMP_RET_ALLOW: |
1912 | break; | |
1913 | default: | |
1914 | return -EOPNOTSUPP; | |
1915 | } | |
1916 | ||
1917 | return 0; | |
1918 | } | |
1919 | ||
6a21cc50 TA |
1920 | static long seccomp_get_notif_sizes(void __user *usizes) |
1921 | { | |
1922 | struct seccomp_notif_sizes sizes = { | |
1923 | .seccomp_notif = sizeof(struct seccomp_notif), | |
1924 | .seccomp_notif_resp = sizeof(struct seccomp_notif_resp), | |
1925 | .seccomp_data = sizeof(struct seccomp_data), | |
1926 | }; | |
1927 | ||
1928 | if (copy_to_user(usizes, &sizes, sizeof(sizes))) | |
1929 | return -EFAULT; | |
1930 | ||
1931 | return 0; | |
1932 | } | |
1933 | ||
48dc92b9 KC |
1934 | /* Common entry point for both prctl and syscall. */ |
1935 | static long do_seccomp(unsigned int op, unsigned int flags, | |
a5662e4d | 1936 | void __user *uargs) |
48dc92b9 KC |
1937 | { |
1938 | switch (op) { | |
1939 | case SECCOMP_SET_MODE_STRICT: | |
1940 | if (flags != 0 || uargs != NULL) | |
1941 | return -EINVAL; | |
1942 | return seccomp_set_mode_strict(); | |
1943 | case SECCOMP_SET_MODE_FILTER: | |
1944 | return seccomp_set_mode_filter(flags, uargs); | |
d612b1fd TH |
1945 | case SECCOMP_GET_ACTION_AVAIL: |
1946 | if (flags != 0) | |
1947 | return -EINVAL; | |
1948 | ||
1949 | return seccomp_get_action_avail(uargs); | |
6a21cc50 TA |
1950 | case SECCOMP_GET_NOTIF_SIZES: |
1951 | if (flags != 0) | |
1952 | return -EINVAL; | |
1953 | ||
1954 | return seccomp_get_notif_sizes(uargs); | |
48dc92b9 KC |
1955 | default: |
1956 | return -EINVAL; | |
1957 | } | |
1958 | } | |
1959 | ||
1960 | SYSCALL_DEFINE3(seccomp, unsigned int, op, unsigned int, flags, | |
a5662e4d | 1961 | void __user *, uargs) |
48dc92b9 KC |
1962 | { |
1963 | return do_seccomp(op, flags, uargs); | |
1964 | } | |
1965 | ||
d78ab02c KC |
1966 | /** |
1967 | * prctl_set_seccomp: configures current->seccomp.mode | |
1968 | * @seccomp_mode: requested mode to use | |
1969 | * @filter: optional struct sock_fprog for use with SECCOMP_MODE_FILTER | |
1970 | * | |
1971 | * Returns 0 on success or -EINVAL on failure. | |
1972 | */ | |
a5662e4d | 1973 | long prctl_set_seccomp(unsigned long seccomp_mode, void __user *filter) |
d78ab02c | 1974 | { |
48dc92b9 | 1975 | unsigned int op; |
a5662e4d | 1976 | void __user *uargs; |
48dc92b9 | 1977 | |
3b23dd12 KC |
1978 | switch (seccomp_mode) { |
1979 | case SECCOMP_MODE_STRICT: | |
48dc92b9 KC |
1980 | op = SECCOMP_SET_MODE_STRICT; |
1981 | /* | |
1982 | * Setting strict mode through prctl always ignored filter, | |
1983 | * so make sure it is always NULL here to pass the internal | |
1984 | * check in do_seccomp(). | |
1985 | */ | |
1986 | uargs = NULL; | |
1987 | break; | |
3b23dd12 | 1988 | case SECCOMP_MODE_FILTER: |
48dc92b9 KC |
1989 | op = SECCOMP_SET_MODE_FILTER; |
1990 | uargs = filter; | |
1991 | break; | |
3b23dd12 KC |
1992 | default: |
1993 | return -EINVAL; | |
1994 | } | |
48dc92b9 KC |
1995 | |
1996 | /* prctl interface doesn't have flags, so they are always zero. */ | |
1997 | return do_seccomp(op, 0, uargs); | |
d78ab02c | 1998 | } |
f8e529ed TA |
1999 | |
2000 | #if defined(CONFIG_SECCOMP_FILTER) && defined(CONFIG_CHECKPOINT_RESTORE) | |
f06eae83 TA |
2001 | static struct seccomp_filter *get_nth_filter(struct task_struct *task, |
2002 | unsigned long filter_off) | |
f8e529ed | 2003 | { |
f06eae83 TA |
2004 | struct seccomp_filter *orig, *filter; |
2005 | unsigned long count; | |
f8e529ed | 2006 | |
f06eae83 TA |
2007 | /* |
2008 | * Note: this is only correct because the caller should be the (ptrace) | |
2009 | * tracer of the task, otherwise lock_task_sighand is needed. | |
2010 | */ | |
f8e529ed | 2011 | spin_lock_irq(&task->sighand->siglock); |
f06eae83 | 2012 | |
f8e529ed | 2013 | if (task->seccomp.mode != SECCOMP_MODE_FILTER) { |
f06eae83 TA |
2014 | spin_unlock_irq(&task->sighand->siglock); |
2015 | return ERR_PTR(-EINVAL); | |
f8e529ed TA |
2016 | } |
2017 | ||
f06eae83 TA |
2018 | orig = task->seccomp.filter; |
2019 | __get_seccomp_filter(orig); | |
2020 | spin_unlock_irq(&task->sighand->siglock); | |
2021 | ||
2022 | count = 0; | |
2023 | for (filter = orig; filter; filter = filter->prev) | |
f8e529ed | 2024 | count++; |
f8e529ed TA |
2025 | |
2026 | if (filter_off >= count) { | |
f06eae83 | 2027 | filter = ERR_PTR(-ENOENT); |
f8e529ed TA |
2028 | goto out; |
2029 | } | |
f8e529ed | 2030 | |
f06eae83 TA |
2031 | count -= filter_off; |
2032 | for (filter = orig; filter && count > 1; filter = filter->prev) | |
f8e529ed | 2033 | count--; |
f8e529ed TA |
2034 | |
2035 | if (WARN_ON(count != 1 || !filter)) { | |
f06eae83 | 2036 | filter = ERR_PTR(-ENOENT); |
f8e529ed TA |
2037 | goto out; |
2038 | } | |
2039 | ||
f06eae83 TA |
2040 | __get_seccomp_filter(filter); |
2041 | ||
2042 | out: | |
2043 | __put_seccomp_filter(orig); | |
2044 | return filter; | |
2045 | } | |
2046 | ||
2047 | long seccomp_get_filter(struct task_struct *task, unsigned long filter_off, | |
2048 | void __user *data) | |
2049 | { | |
2050 | struct seccomp_filter *filter; | |
2051 | struct sock_fprog_kern *fprog; | |
2052 | long ret; | |
2053 | ||
2054 | if (!capable(CAP_SYS_ADMIN) || | |
2055 | current->seccomp.mode != SECCOMP_MODE_DISABLED) { | |
2056 | return -EACCES; | |
2057 | } | |
2058 | ||
2059 | filter = get_nth_filter(task, filter_off); | |
2060 | if (IS_ERR(filter)) | |
2061 | return PTR_ERR(filter); | |
2062 | ||
f8e529ed TA |
2063 | fprog = filter->prog->orig_prog; |
2064 | if (!fprog) { | |
470bf1f2 | 2065 | /* This must be a new non-cBPF filter, since we save |
f8e529ed TA |
2066 | * every cBPF filter's orig_prog above when |
2067 | * CONFIG_CHECKPOINT_RESTORE is enabled. | |
2068 | */ | |
2069 | ret = -EMEDIUMTYPE; | |
2070 | goto out; | |
2071 | } | |
2072 | ||
2073 | ret = fprog->len; | |
2074 | if (!data) | |
2075 | goto out; | |
2076 | ||
f8e529ed TA |
2077 | if (copy_to_user(data, fprog->filter, bpf_classic_proglen(fprog))) |
2078 | ret = -EFAULT; | |
2079 | ||
f8e529ed | 2080 | out: |
66a733ea | 2081 | __put_seccomp_filter(filter); |
f8e529ed | 2082 | return ret; |
f8e529ed | 2083 | } |
f8e529ed | 2084 | |
26500475 TA |
2085 | long seccomp_get_metadata(struct task_struct *task, |
2086 | unsigned long size, void __user *data) | |
2087 | { | |
2088 | long ret; | |
2089 | struct seccomp_filter *filter; | |
2090 | struct seccomp_metadata kmd = {}; | |
2091 | ||
2092 | if (!capable(CAP_SYS_ADMIN) || | |
2093 | current->seccomp.mode != SECCOMP_MODE_DISABLED) { | |
2094 | return -EACCES; | |
2095 | } | |
2096 | ||
2097 | size = min_t(unsigned long, size, sizeof(kmd)); | |
2098 | ||
63bb0045 TA |
2099 | if (size < sizeof(kmd.filter_off)) |
2100 | return -EINVAL; | |
2101 | ||
2102 | if (copy_from_user(&kmd.filter_off, data, sizeof(kmd.filter_off))) | |
26500475 TA |
2103 | return -EFAULT; |
2104 | ||
2105 | filter = get_nth_filter(task, kmd.filter_off); | |
2106 | if (IS_ERR(filter)) | |
2107 | return PTR_ERR(filter); | |
2108 | ||
26500475 TA |
2109 | if (filter->log) |
2110 | kmd.flags |= SECCOMP_FILTER_FLAG_LOG; | |
2111 | ||
2112 | ret = size; | |
2113 | if (copy_to_user(data, &kmd, size)) | |
2114 | ret = -EFAULT; | |
2115 | ||
2116 | __put_seccomp_filter(filter); | |
f8e529ed TA |
2117 | return ret; |
2118 | } | |
2119 | #endif | |
8e5f1ad1 TH |
2120 | |
2121 | #ifdef CONFIG_SYSCTL | |
2122 | ||
2123 | /* Human readable action names for friendly sysctl interaction */ | |
0466bdb9 | 2124 | #define SECCOMP_RET_KILL_PROCESS_NAME "kill_process" |
fd76875c | 2125 | #define SECCOMP_RET_KILL_THREAD_NAME "kill_thread" |
8e5f1ad1 TH |
2126 | #define SECCOMP_RET_TRAP_NAME "trap" |
2127 | #define SECCOMP_RET_ERRNO_NAME "errno" | |
6a21cc50 | 2128 | #define SECCOMP_RET_USER_NOTIF_NAME "user_notif" |
8e5f1ad1 | 2129 | #define SECCOMP_RET_TRACE_NAME "trace" |
59f5cf44 | 2130 | #define SECCOMP_RET_LOG_NAME "log" |
8e5f1ad1 TH |
2131 | #define SECCOMP_RET_ALLOW_NAME "allow" |
2132 | ||
fd76875c | 2133 | static const char seccomp_actions_avail[] = |
0466bdb9 | 2134 | SECCOMP_RET_KILL_PROCESS_NAME " " |
fd76875c KC |
2135 | SECCOMP_RET_KILL_THREAD_NAME " " |
2136 | SECCOMP_RET_TRAP_NAME " " | |
2137 | SECCOMP_RET_ERRNO_NAME " " | |
6a21cc50 | 2138 | SECCOMP_RET_USER_NOTIF_NAME " " |
fd76875c KC |
2139 | SECCOMP_RET_TRACE_NAME " " |
2140 | SECCOMP_RET_LOG_NAME " " | |
2141 | SECCOMP_RET_ALLOW_NAME; | |
8e5f1ad1 | 2142 | |
0ddec0fc TH |
2143 | struct seccomp_log_name { |
2144 | u32 log; | |
2145 | const char *name; | |
2146 | }; | |
2147 | ||
2148 | static const struct seccomp_log_name seccomp_log_names[] = { | |
0466bdb9 | 2149 | { SECCOMP_LOG_KILL_PROCESS, SECCOMP_RET_KILL_PROCESS_NAME }, |
fd76875c | 2150 | { SECCOMP_LOG_KILL_THREAD, SECCOMP_RET_KILL_THREAD_NAME }, |
0ddec0fc TH |
2151 | { SECCOMP_LOG_TRAP, SECCOMP_RET_TRAP_NAME }, |
2152 | { SECCOMP_LOG_ERRNO, SECCOMP_RET_ERRNO_NAME }, | |
6a21cc50 | 2153 | { SECCOMP_LOG_USER_NOTIF, SECCOMP_RET_USER_NOTIF_NAME }, |
0ddec0fc | 2154 | { SECCOMP_LOG_TRACE, SECCOMP_RET_TRACE_NAME }, |
59f5cf44 | 2155 | { SECCOMP_LOG_LOG, SECCOMP_RET_LOG_NAME }, |
0ddec0fc TH |
2156 | { SECCOMP_LOG_ALLOW, SECCOMP_RET_ALLOW_NAME }, |
2157 | { } | |
2158 | }; | |
2159 | ||
2160 | static bool seccomp_names_from_actions_logged(char *names, size_t size, | |
beb44aca TH |
2161 | u32 actions_logged, |
2162 | const char *sep) | |
0ddec0fc TH |
2163 | { |
2164 | const struct seccomp_log_name *cur; | |
beb44aca | 2165 | bool append_sep = false; |
0ddec0fc TH |
2166 | |
2167 | for (cur = seccomp_log_names; cur->name && size; cur++) { | |
2168 | ssize_t ret; | |
2169 | ||
2170 | if (!(actions_logged & cur->log)) | |
2171 | continue; | |
2172 | ||
beb44aca TH |
2173 | if (append_sep) { |
2174 | ret = strscpy(names, sep, size); | |
0ddec0fc TH |
2175 | if (ret < 0) |
2176 | return false; | |
2177 | ||
2178 | names += ret; | |
2179 | size -= ret; | |
2180 | } else | |
beb44aca | 2181 | append_sep = true; |
0ddec0fc TH |
2182 | |
2183 | ret = strscpy(names, cur->name, size); | |
2184 | if (ret < 0) | |
2185 | return false; | |
2186 | ||
2187 | names += ret; | |
2188 | size -= ret; | |
2189 | } | |
2190 | ||
2191 | return true; | |
2192 | } | |
2193 | ||
2194 | static bool seccomp_action_logged_from_name(u32 *action_logged, | |
2195 | const char *name) | |
2196 | { | |
2197 | const struct seccomp_log_name *cur; | |
2198 | ||
2199 | for (cur = seccomp_log_names; cur->name; cur++) { | |
2200 | if (!strcmp(cur->name, name)) { | |
2201 | *action_logged = cur->log; | |
2202 | return true; | |
2203 | } | |
2204 | } | |
2205 | ||
2206 | return false; | |
2207 | } | |
2208 | ||
2209 | static bool seccomp_actions_logged_from_names(u32 *actions_logged, char *names) | |
2210 | { | |
2211 | char *name; | |
2212 | ||
2213 | *actions_logged = 0; | |
2214 | while ((name = strsep(&names, " ")) && *name) { | |
2215 | u32 action_logged = 0; | |
2216 | ||
2217 | if (!seccomp_action_logged_from_name(&action_logged, name)) | |
2218 | return false; | |
2219 | ||
2220 | *actions_logged |= action_logged; | |
2221 | } | |
2222 | ||
2223 | return true; | |
2224 | } | |
2225 | ||
fab686eb | 2226 | static int read_actions_logged(struct ctl_table *ro_table, void *buffer, |
d013db02 | 2227 | size_t *lenp, loff_t *ppos) |
0ddec0fc TH |
2228 | { |
2229 | char names[sizeof(seccomp_actions_avail)]; | |
2230 | struct ctl_table table; | |
d013db02 TH |
2231 | |
2232 | memset(names, 0, sizeof(names)); | |
2233 | ||
2234 | if (!seccomp_names_from_actions_logged(names, sizeof(names), | |
beb44aca | 2235 | seccomp_actions_logged, " ")) |
d013db02 TH |
2236 | return -EINVAL; |
2237 | ||
2238 | table = *ro_table; | |
2239 | table.data = names; | |
2240 | table.maxlen = sizeof(names); | |
2241 | return proc_dostring(&table, 0, buffer, lenp, ppos); | |
2242 | } | |
2243 | ||
fab686eb | 2244 | static int write_actions_logged(struct ctl_table *ro_table, void *buffer, |
ea6eca77 | 2245 | size_t *lenp, loff_t *ppos, u32 *actions_logged) |
0ddec0fc TH |
2246 | { |
2247 | char names[sizeof(seccomp_actions_avail)]; | |
2248 | struct ctl_table table; | |
2249 | int ret; | |
2250 | ||
d013db02 | 2251 | if (!capable(CAP_SYS_ADMIN)) |
0ddec0fc TH |
2252 | return -EPERM; |
2253 | ||
2254 | memset(names, 0, sizeof(names)); | |
2255 | ||
0ddec0fc TH |
2256 | table = *ro_table; |
2257 | table.data = names; | |
2258 | table.maxlen = sizeof(names); | |
d013db02 | 2259 | ret = proc_dostring(&table, 1, buffer, lenp, ppos); |
0ddec0fc TH |
2260 | if (ret) |
2261 | return ret; | |
2262 | ||
ea6eca77 | 2263 | if (!seccomp_actions_logged_from_names(actions_logged, table.data)) |
d013db02 | 2264 | return -EINVAL; |
0ddec0fc | 2265 | |
ea6eca77 | 2266 | if (*actions_logged & SECCOMP_LOG_ALLOW) |
d013db02 | 2267 | return -EINVAL; |
0ddec0fc | 2268 | |
ea6eca77 | 2269 | seccomp_actions_logged = *actions_logged; |
0ddec0fc TH |
2270 | return 0; |
2271 | } | |
0ddec0fc | 2272 | |
ea6eca77 TH |
2273 | static void audit_actions_logged(u32 actions_logged, u32 old_actions_logged, |
2274 | int ret) | |
2275 | { | |
2276 | char names[sizeof(seccomp_actions_avail)]; | |
2277 | char old_names[sizeof(seccomp_actions_avail)]; | |
2278 | const char *new = names; | |
2279 | const char *old = old_names; | |
0ddec0fc | 2280 | |
ea6eca77 TH |
2281 | if (!audit_enabled) |
2282 | return; | |
2283 | ||
2284 | memset(names, 0, sizeof(names)); | |
2285 | memset(old_names, 0, sizeof(old_names)); | |
2286 | ||
2287 | if (ret) | |
2288 | new = "?"; | |
2289 | else if (!actions_logged) | |
2290 | new = "(none)"; | |
2291 | else if (!seccomp_names_from_actions_logged(names, sizeof(names), | |
2292 | actions_logged, ",")) | |
2293 | new = "?"; | |
2294 | ||
2295 | if (!old_actions_logged) | |
2296 | old = "(none)"; | |
2297 | else if (!seccomp_names_from_actions_logged(old_names, | |
2298 | sizeof(old_names), | |
2299 | old_actions_logged, ",")) | |
2300 | old = "?"; | |
2301 | ||
2302 | return audit_seccomp_actions_logged(new, old, !ret); | |
2303 | } | |
2304 | ||
d013db02 | 2305 | static int seccomp_actions_logged_handler(struct ctl_table *ro_table, int write, |
32927393 | 2306 | void *buffer, size_t *lenp, |
d013db02 TH |
2307 | loff_t *ppos) |
2308 | { | |
ea6eca77 TH |
2309 | int ret; |
2310 | ||
2311 | if (write) { | |
2312 | u32 actions_logged = 0; | |
2313 | u32 old_actions_logged = seccomp_actions_logged; | |
2314 | ||
2315 | ret = write_actions_logged(ro_table, buffer, lenp, ppos, | |
2316 | &actions_logged); | |
2317 | audit_actions_logged(actions_logged, old_actions_logged, ret); | |
2318 | } else | |
2319 | ret = read_actions_logged(ro_table, buffer, lenp, ppos); | |
2320 | ||
2321 | return ret; | |
0ddec0fc TH |
2322 | } |
2323 | ||
8e5f1ad1 TH |
2324 | static struct ctl_path seccomp_sysctl_path[] = { |
2325 | { .procname = "kernel", }, | |
2326 | { .procname = "seccomp", }, | |
2327 | { } | |
2328 | }; | |
2329 | ||
2330 | static struct ctl_table seccomp_sysctl_table[] = { | |
2331 | { | |
2332 | .procname = "actions_avail", | |
2333 | .data = (void *) &seccomp_actions_avail, | |
2334 | .maxlen = sizeof(seccomp_actions_avail), | |
2335 | .mode = 0444, | |
2336 | .proc_handler = proc_dostring, | |
2337 | }, | |
0ddec0fc TH |
2338 | { |
2339 | .procname = "actions_logged", | |
2340 | .mode = 0644, | |
2341 | .proc_handler = seccomp_actions_logged_handler, | |
2342 | }, | |
8e5f1ad1 TH |
2343 | { } |
2344 | }; | |
2345 | ||
2346 | static int __init seccomp_sysctl_init(void) | |
2347 | { | |
2348 | struct ctl_table_header *hdr; | |
2349 | ||
2350 | hdr = register_sysctl_paths(seccomp_sysctl_path, seccomp_sysctl_table); | |
2351 | if (!hdr) | |
e68f9d49 | 2352 | pr_warn("sysctl registration failed\n"); |
8e5f1ad1 TH |
2353 | else |
2354 | kmemleak_not_leak(hdr); | |
2355 | ||
2356 | return 0; | |
2357 | } | |
2358 | ||
2359 | device_initcall(seccomp_sysctl_init) | |
2360 | ||
2361 | #endif /* CONFIG_SYSCTL */ | |
0d8315dd YZ |
2362 | |
2363 | #ifdef CONFIG_SECCOMP_CACHE_DEBUG | |
2364 | /* Currently CONFIG_SECCOMP_CACHE_DEBUG implies SECCOMP_ARCH_NATIVE */ | |
2365 | static void proc_pid_seccomp_cache_arch(struct seq_file *m, const char *name, | |
2366 | const void *bitmap, size_t bitmap_size) | |
2367 | { | |
2368 | int nr; | |
2369 | ||
2370 | for (nr = 0; nr < bitmap_size; nr++) { | |
2371 | bool cached = test_bit(nr, bitmap); | |
2372 | char *status = cached ? "ALLOW" : "FILTER"; | |
2373 | ||
2374 | seq_printf(m, "%s %d %s\n", name, nr, status); | |
2375 | } | |
2376 | } | |
2377 | ||
2378 | int proc_pid_seccomp_cache(struct seq_file *m, struct pid_namespace *ns, | |
2379 | struct pid *pid, struct task_struct *task) | |
2380 | { | |
2381 | struct seccomp_filter *f; | |
2382 | unsigned long flags; | |
2383 | ||
2384 | /* | |
2385 | * We don't want some sandboxed process to know what their seccomp | |
2386 | * filters consist of. | |
2387 | */ | |
2388 | if (!file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN)) | |
2389 | return -EACCES; | |
2390 | ||
2391 | if (!lock_task_sighand(task, &flags)) | |
2392 | return -ESRCH; | |
2393 | ||
2394 | f = READ_ONCE(task->seccomp.filter); | |
2395 | if (!f) { | |
2396 | unlock_task_sighand(task, &flags); | |
2397 | return 0; | |
2398 | } | |
2399 | ||
2400 | /* prevent filter from being freed while we are printing it */ | |
2401 | __get_seccomp_filter(f); | |
2402 | unlock_task_sighand(task, &flags); | |
2403 | ||
2404 | proc_pid_seccomp_cache_arch(m, SECCOMP_ARCH_NATIVE_NAME, | |
2405 | f->cache.allow_native, | |
2406 | SECCOMP_ARCH_NATIVE_NR); | |
2407 | ||
2408 | #ifdef SECCOMP_ARCH_COMPAT | |
2409 | proc_pid_seccomp_cache_arch(m, SECCOMP_ARCH_COMPAT_NAME, | |
2410 | f->cache.allow_compat, | |
2411 | SECCOMP_ARCH_COMPAT_NR); | |
2412 | #endif /* SECCOMP_ARCH_COMPAT */ | |
2413 | ||
2414 | __put_seccomp_filter(f); | |
2415 | return 0; | |
2416 | } | |
2417 | #endif /* CONFIG_SECCOMP_CACHE_DEBUG */ |