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