| 1 | |
| 2 | * linux/kernel/signal.c
|
| 3 | *
|
| 4 | * Copyright (C) 1991, 1992 Linus Torvalds
|
| 5 | *
|
| 6 | * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson
|
| 7 | *
|
| 8 | * 2003-06-02 Jim Houston - Concurrent Computer Corp.
|
| 9 | * Changes to use preallocated sigqueue structures
|
| 10 | * to allow signals to be sent reliably.
|
| 11 |
|
| 12 |
|
| 13 | #include <linux/slab.h>
|
| 14 | #include <linux/export.h>
|
| 15 | #include <linux/init.h>
|
| 16 | #include <linux/sched.h>
|
| 17 | #include <linux/fs.h>
|
| 18 | #include <linux/tty.h>
|
| 19 | #include <linux/binfmts.h>
|
| 20 | #include <linux/coredump.h>
|
| 21 | #include <linux/security.h>
|
| 22 | #include <linux/syscalls.h>
|
| 23 | #include <linux/ptrace.h>
|
| 24 | #include <linux/signal.h>
|
| 25 | #include <linux/signalfd.h>
|
| 26 | #include <linux/ratelimit.h>
|
| 27 | #include <linux/tracehook.h>
|
| 28 | #include <linux/capability.h>
|
| 29 | #include <linux/freezer.h>
|
| 30 | #include <linux/pid_namespace.h>
|
| 31 | #include <linux/nsproxy.h>
|
| 32 | #include <linux/user_namespace.h>
|
| 33 | #include <linux/uprobes.h>
|
| 34 | #include <linux/compat.h>
|
| 35 | #include <linux/cn_proc.h>
|
| 36 | #include <linux/compiler.h>
|
| 37 |
|
| 38 | #define CREATE_TRACE_POINTS
|
| 39 | #include <trace/events/signal.h>
|
| 40 |
|
| 41 | #include <asm/param.h>
|
| 42 | #include <asm/uaccess.h>
|
| 43 | #include <asm/unistd.h>
|
| 44 | #include <asm/siginfo.h>
|
| 45 | #include <asm/cacheflush.h>
|
| 46 | #include "audit.h"
|
| 47 |
|
| 48 | |
| 49 | * SLAB caches for signal bits.
|
| 50 |
|
| 51 |
|
| 52 | static struct kmem_cache *sigqueue_cachep;
|
| 53 |
|
| 54 | int print_fatal_signals __read_mostly;
|
| 55 |
|
| 56 | static void __user *sig_handler(struct task_struct *t, int sig)
|
| 57 | {
|
| 58 | return t->sighand->action[sig - 1].sa.sa_handler;
|
| 59 | }
|
| 60 |
|
| 61 | static int sig_handler_ignored(void __user *handler, int sig)
|
| 62 | {
|
| 63 |
|
| 64 | return handler == SIG_IGN ||
|
| 65 | (handler == SIG_DFL && sig_kernel_ignore(sig));
|
| 66 | }
|
| 67 |
|
| 68 | static int sig_task_ignored(struct task_struct *t, int sig, bool force)
|
| 69 | {
|
| 70 | void __user *handler;
|
| 71 |
|
| 72 | handler = sig_handler(t, sig);
|
| 73 |
|
| 74 | if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
|
| 75 | handler == SIG_DFL && !force)
|
| 76 | return 1;
|
| 77 |
|
| 78 | return sig_handler_ignored(handler, sig);
|
| 79 | }
|
| 80 |
|
| 81 | static int sig_ignored(struct task_struct *t, int sig, bool force)
|
| 82 | {
|
| 83 | |
| 84 | * Blocked signals are never ignored, since the
|
| 85 | * signal handler may change by the time it is
|
| 86 | * unblocked.
|
| 87 |
|
| 88 | if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
|
| 89 | return 0;
|
| 90 |
|
| 91 | if (!sig_task_ignored(t, sig, force))
|
| 92 | return 0;
|
| 93 |
|
| 94 | |
| 95 | * Tracers may want to know about even ignored signals.
|
| 96 |
|
| 97 | return !t->ptrace;
|
| 98 | }
|
| 99 |
|
| 100 | |
| 101 | * Re-calculate pending state from the set of locally pending
|
| 102 | * signals, globally pending signals, and blocked signals.
|
| 103 |
|
| 104 | static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked)
|
| 105 | {
|
| 106 | unsigned long ready;
|
| 107 | long i;
|
| 108 |
|
| 109 | switch (_NSIG_WORDS) {
|
| 110 | default:
|
| 111 | for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
|
| 112 | ready |= signal->sig[i] &~ blocked->sig[i];
|
| 113 | break;
|
| 114 |
|
| 115 | case 4: ready = signal->sig[3] &~ blocked->sig[3];
|
| 116 | ready |= signal->sig[2] &~ blocked->sig[2];
|
| 117 | ready |= signal->sig[1] &~ blocked->sig[1];
|
| 118 | ready |= signal->sig[0] &~ blocked->sig[0];
|
| 119 | break;
|
| 120 |
|
| 121 | case 2: ready = signal->sig[1] &~ blocked->sig[1];
|
| 122 | ready |= signal->sig[0] &~ blocked->sig[0];
|
| 123 | break;
|
| 124 |
|
| 125 | case 1: ready = signal->sig[0] &~ blocked->sig[0];
|
| 126 | }
|
| 127 | return ready != 0;
|
| 128 | }
|
| 129 |
|
| 130 | #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
|
| 131 |
|
| 132 | static int recalc_sigpending_tsk(struct task_struct *t)
|
| 133 | {
|
| 134 | if ((t->jobctl & JOBCTL_PENDING_MASK) ||
|
| 135 | PENDING(&t->pending, &t->blocked) ||
|
| 136 | PENDING(&t->signal->shared_pending, &t->blocked)) {
|
| 137 | set_tsk_thread_flag(t, TIF_SIGPENDING);
|
| 138 | return 1;
|
| 139 | }
|
| 140 | |
| 141 | * We must never clear the flag in another thread, or in current
|
| 142 | * when it's possible the current syscall is returning -ERESTART*.
|
| 143 | * So we don't clear it here, and only callers who know they should do.
|
| 144 |
|
| 145 | return 0;
|
| 146 | }
|
| 147 |
|
| 148 | |
| 149 | * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
|
| 150 | * This is superfluous when called on current, the wakeup is a harmless no-op.
|
| 151 |
|
| 152 | void recalc_sigpending_and_wake(struct task_struct *t)
|
| 153 | {
|
| 154 | if (recalc_sigpending_tsk(t))
|
| 155 | signal_wake_up(t, 0);
|
| 156 | }
|
| 157 |
|
| 158 | void recalc_sigpending(void)
|
| 159 | {
|
| 160 | if (!recalc_sigpending_tsk(current) && !freezing(current))
|
| 161 | clear_thread_flag(TIF_SIGPENDING);
|
| 162 |
|
| 163 | }
|
| 164 |
|
| 165 |
|
| 166 |
|
| 167 | #define SYNCHRONOUS_MASK \
|
| 168 | (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
|
| 169 | sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
|
| 170 |
|
| 171 | int next_signal(struct sigpending *pending, sigset_t *mask)
|
| 172 | {
|
| 173 | unsigned long i, *s, *m, x;
|
| 174 | int sig = 0;
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| 175 |
|
| 176 | s = pending->signal.sig;
|
| 177 | m = mask->sig;
|
| 178 |
|
| 179 | |
| 180 | * Handle the first word specially: it contains the
|
| 181 | * synchronous signals that need to be dequeued first.
|
| 182 |
|
| 183 | x = *s &~ *m;
|
| 184 | if (x) {
|
| 185 | if (x & SYNCHRONOUS_MASK)
|
| 186 | x &= SYNCHRONOUS_MASK;
|
| 187 | sig = ffz(~x) + 1;
|
| 188 | return sig;
|
| 189 | }
|
| 190 |
|
| 191 | switch (_NSIG_WORDS) {
|
| 192 | default:
|
| 193 | for (i = 1; i < _NSIG_WORDS; ++i) {
|
| 194 | x = *++s &~ *++m;
|
| 195 | if (!x)
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| 196 | continue;
|
| 197 | sig = ffz(~x) + i*_NSIG_BPW + 1;
|
| 198 | break;
|
| 199 | }
|
| 200 | break;
|
| 201 |
|
| 202 | case 2:
|
| 203 | x = s[1] &~ m[1];
|
| 204 | if (!x)
|
| 205 | break;
|
| 206 | sig = ffz(~x) + _NSIG_BPW + 1;
|
| 207 | break;
|
| 208 |
|
| 209 | case 1:
|
| 210 |
|
| 211 | break;
|
| 212 | }
|
| 213 |
|
| 214 | return sig;
|
| 215 | }
|
| 216 |
|
| 217 | static inline void print_dropped_signal(int sig)
|
| 218 | {
|
| 219 | static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
|
| 220 |
|
| 221 | if (!print_fatal_signals)
|
| 222 | return;
|
| 223 |
|
| 224 | if (!__ratelimit(&ratelimit_state))
|
| 225 | return;
|
| 226 |
|
| 227 | pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
|
| 228 | current->comm, current->pid, sig);
|
| 229 | }
|
| 230 |
|
| 231 | |
| 232 | * task_set_jobctl_pending - set jobctl pending bits
|
| 233 | * @task: target task
|
| 234 | * @mask: pending bits to set
|
| 235 | *
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| 236 | * Clear @mask from @task->jobctl. @mask must be subset of
|
| 237 | * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
|
| 238 | * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
|
| 239 | * cleared. If @task is already being killed or exiting, this function
|
| 240 | * becomes noop.
|
| 241 | *
|
| 242 | * CONTEXT:
|
| 243 | * Must be called with @task->sighand->siglock held.
|
| 244 | *
|
| 245 | * RETURNS:
|
| 246 | * %true if @mask is set, %false if made noop because @task was dying.
|
| 247 |
|
| 248 | bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask)
|
| 249 | {
|
| 250 | BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME |
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| 251 | JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
|
| 252 | BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
|
| 253 |
|
| 254 | if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING)))
|
| 255 | return false;
|
| 256 |
|
| 257 | if (mask & JOBCTL_STOP_SIGMASK)
|
| 258 | task->jobctl &= ~JOBCTL_STOP_SIGMASK;
|
| 259 |
|
| 260 | task->jobctl |= mask;
|
| 261 | return true;
|
| 262 | }
|
| 263 |
|
| 264 | |
| 265 | * task_clear_jobctl_trapping - clear jobctl trapping bit
|
| 266 | * @task: target task
|
| 267 | *
|
| 268 | * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
|
| 269 | * Clear it and wake up the ptracer. Note that we don't need any further
|
| 270 | * locking. @task->siglock guarantees that @task->parent points to the
|
| 271 | * ptracer.
|
| 272 | *
|
| 273 | * CONTEXT:
|
| 274 | * Must be called with @task->sighand->siglock held.
|
| 275 |
|
| 276 | void task_clear_jobctl_trapping(struct task_struct *task)
|
| 277 | {
|
| 278 | if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
|
| 279 | task->jobctl &= ~JOBCTL_TRAPPING;
|
| 280 | smp_mb();
|
| 281 | wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
|
| 282 | }
|
| 283 | }
|
| 284 |
|
| 285 | |
| 286 | * task_clear_jobctl_pending - clear jobctl pending bits
|
| 287 | * @task: target task
|
| 288 | * @mask: pending bits to clear
|
| 289 | *
|
| 290 | * Clear @mask from @task->jobctl. @mask must be subset of
|
| 291 | * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
|
| 292 | * STOP bits are cleared together.
|
| 293 | *
|
| 294 | * If clearing of @mask leaves no stop or trap pending, this function calls
|
| 295 | * task_clear_jobctl_trapping().
|
| 296 | *
|
| 297 | * CONTEXT:
|
| 298 | * Must be called with @task->sighand->siglock held.
|
| 299 |
|
| 300 | void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask)
|
| 301 | {
|
| 302 | BUG_ON(mask & ~JOBCTL_PENDING_MASK);
|
| 303 |
|
| 304 | if (mask & JOBCTL_STOP_PENDING)
|
| 305 | mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED;
|
| 306 |
|
| 307 | task->jobctl &= ~mask;
|
| 308 |
|
| 309 | if (!(task->jobctl & JOBCTL_PENDING_MASK))
|
| 310 | task_clear_jobctl_trapping(task);
|
| 311 | }
|
| 312 |
|
| 313 | |
| 314 | * task_participate_group_stop - participate in a group stop
|
| 315 | * @task: task participating in a group stop
|
| 316 | *
|
| 317 | * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
|
| 318 | * Group stop states are cleared and the group stop count is consumed if
|
| 319 | * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
|
| 320 | * stop, the appropriate %SIGNAL_* flags are set.
|
| 321 | *
|
| 322 | * CONTEXT:
|
| 323 | * Must be called with @task->sighand->siglock held.
|
| 324 | *
|
| 325 | * RETURNS:
|
| 326 | * %true if group stop completion should be notified to the parent, %false
|
| 327 | * otherwise.
|
| 328 |
|
| 329 | static bool task_participate_group_stop(struct task_struct *task)
|
| 330 | {
|
| 331 | struct signal_struct *sig = task->signal;
|
| 332 | bool consume = task->jobctl & JOBCTL_STOP_CONSUME;
|
| 333 |
|
| 334 | WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING));
|
| 335 |
|
| 336 | task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING);
|
| 337 |
|
| 338 | if (!consume)
|
| 339 | return false;
|
| 340 |
|
| 341 | if (!WARN_ON_ONCE(sig->group_stop_count == 0))
|
| 342 | sig->group_stop_count--;
|
| 343 |
|
| 344 | |
| 345 | * Tell the caller to notify completion iff we are entering into a
|
| 346 | * fresh group stop. Read comment in do_signal_stop() for details.
|
| 347 |
|
| 348 | if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
|
| 349 | sig->flags = SIGNAL_STOP_STOPPED;
|
| 350 | return true;
|
| 351 | }
|
| 352 | return false;
|
| 353 | }
|
| 354 |
|
| 355 | |
| 356 | * allocate a new signal queue record
|
| 357 | * - this may be called without locks if and only if t == current, otherwise an
|
| 358 | * appropriate lock must be held to stop the target task from exiting
|
| 359 |
|
| 360 | static struct sigqueue *
|
| 361 | __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
|
| 362 | {
|
| 363 | struct sigqueue *q = NULL;
|
| 364 | struct user_struct *user;
|
| 365 |
|
| 366 | |
| 367 | * Protect access to @t credentials. This can go away when all
|
| 368 | * callers hold rcu read lock.
|
| 369 |
|
| 370 | rcu_read_lock();
|
| 371 | user = get_uid(__task_cred(t)->user);
|
| 372 | atomic_inc(&user->sigpending);
|
| 373 | rcu_read_unlock();
|
| 374 |
|
| 375 | if (override_rlimit ||
|
| 376 | atomic_read(&user->sigpending) <=
|
| 377 | task_rlimit(t, RLIMIT_SIGPENDING)) {
|
| 378 | q = kmem_cache_alloc(sigqueue_cachep, flags);
|
| 379 | } else {
|
| 380 | print_dropped_signal(sig);
|
| 381 | }
|
| 382 |
|
| 383 | if (unlikely(q == NULL)) {
|
| 384 | atomic_dec(&user->sigpending);
|
| 385 | free_uid(user);
|
| 386 | } else {
|
| 387 | INIT_LIST_HEAD(&q->list);
|
| 388 | q->flags = 0;
|
| 389 | q->user = user;
|
| 390 | }
|
| 391 |
|
| 392 | return q;
|
| 393 | }
|
| 394 |
|
| 395 | static void __sigqueue_free(struct sigqueue *q)
|
| 396 | {
|
| 397 | if (q->flags & SIGQUEUE_PREALLOC)
|
| 398 | return;
|
| 399 | atomic_dec(&q->user->sigpending);
|
| 400 | free_uid(q->user);
|
| 401 | kmem_cache_free(sigqueue_cachep, q);
|
| 402 | }
|
| 403 |
|
| 404 | void flush_sigqueue(struct sigpending *queue)
|
| 405 | {
|
| 406 | struct sigqueue *q;
|
| 407 |
|
| 408 | sigemptyset(&queue->signal);
|
| 409 | while (!list_empty(&queue->list)) {
|
| 410 | q = list_entry(queue->list.next, struct sigqueue , list);
|
| 411 | list_del_init(&q->list);
|
| 412 | __sigqueue_free(q);
|
| 413 | }
|
| 414 | }
|
| 415 |
|
| 416 | |
| 417 | * Flush all pending signals for this kthread.
|
| 418 |
|
| 419 | void flush_signals(struct task_struct *t)
|
| 420 | {
|
| 421 | unsigned long flags;
|
| 422 |
|
| 423 | spin_lock_irqsave(&t->sighand->siglock, flags);
|
| 424 | clear_tsk_thread_flag(t, TIF_SIGPENDING);
|
| 425 | flush_sigqueue(&t->pending);
|
| 426 | flush_sigqueue(&t->signal->shared_pending);
|
| 427 | spin_unlock_irqrestore(&t->sighand->siglock, flags);
|
| 428 | }
|
| 429 |
|
| 430 | static void __flush_itimer_signals(struct sigpending *pending)
|
| 431 | {
|
| 432 | sigset_t signal, retain;
|
| 433 | struct sigqueue *q, *n;
|
| 434 |
|
| 435 | signal = pending->signal;
|
| 436 | sigemptyset(&retain);
|
| 437 |
|
| 438 | list_for_each_entry_safe(q, n, &pending->list, list) {
|
| 439 | int sig = q->info.si_signo;
|
| 440 |
|
| 441 | if (likely(q->info.si_code != SI_TIMER)) {
|
| 442 | sigaddset(&retain, sig);
|
| 443 | } else {
|
| 444 | sigdelset(&signal, sig);
|
| 445 | list_del_init(&q->list);
|
| 446 | __sigqueue_free(q);
|
| 447 | }
|
| 448 | }
|
| 449 |
|
| 450 | sigorsets(&pending->signal, &signal, &retain);
|
| 451 | }
|
| 452 |
|
| 453 | void flush_itimer_signals(void)
|
| 454 | {
|
| 455 | struct task_struct *tsk = current;
|
| 456 | unsigned long flags;
|
| 457 |
|
| 458 | spin_lock_irqsave(&tsk->sighand->siglock, flags);
|
| 459 | __flush_itimer_signals(&tsk->pending);
|
| 460 | __flush_itimer_signals(&tsk->signal->shared_pending);
|
| 461 | spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
|
| 462 | }
|
| 463 |
|
| 464 | void ignore_signals(struct task_struct *t)
|
| 465 | {
|
| 466 | int i;
|
| 467 |
|
| 468 | for (i = 0; i < _NSIG; ++i)
|
| 469 | t->sighand->action[i].sa.sa_handler = SIG_IGN;
|
| 470 |
|
| 471 | flush_signals(t);
|
| 472 | }
|
| 473 |
|
| 474 | |
| 475 | * Flush all handlers for a task.
|
| 476 |
|
| 477 |
|
| 478 | void
|
| 479 | flush_signal_handlers(struct task_struct *t, int force_default)
|
| 480 | {
|
| 481 | int i;
|
| 482 | struct k_sigaction *ka = &t->sighand->action[0];
|
| 483 | for (i = _NSIG ; i != 0 ; i--) {
|
| 484 | if (force_default || ka->sa.sa_handler != SIG_IGN)
|
| 485 | ka->sa.sa_handler = SIG_DFL;
|
| 486 | ka->sa.sa_flags = 0;
|
| 487 | #ifdef __ARCH_HAS_SA_RESTORER
|
| 488 | ka->sa.sa_restorer = NULL;
|
| 489 | #endif
|
| 490 | sigemptyset(&ka->sa.sa_mask);
|
| 491 | ka++;
|
| 492 | }
|
| 493 | }
|
| 494 |
|
| 495 | int unhandled_signal(struct task_struct *tsk, int sig)
|
| 496 | {
|
| 497 | void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
|
| 498 | if (is_global_init(tsk))
|
| 499 | return 1;
|
| 500 | if (handler != SIG_IGN && handler != SIG_DFL)
|
| 501 | return 0;
|
| 502 |
|
| 503 | return !tsk->ptrace;
|
| 504 | }
|
| 505 |
|
| 506 | static void collect_signal(int sig, struct sigpending *list, siginfo_t *info)
|
| 507 | {
|
| 508 | struct sigqueue *q, *first = NULL;
|
| 509 |
|
| 510 | |
| 511 | * Collect the siginfo appropriate to this signal. Check if
|
| 512 | * there is another siginfo for the same signal.
|
| 513 |
|
| 514 | list_for_each_entry(q, &list->list, list) {
|
| 515 | if (q->info.si_signo == sig) {
|
| 516 | if (first)
|
| 517 | goto still_pending;
|
| 518 | first = q;
|
| 519 | }
|
| 520 | }
|
| 521 |
|
| 522 | sigdelset(&list->signal, sig);
|
| 523 |
|
| 524 | if (first) {
|
| 525 | still_pending:
|
| 526 | list_del_init(&first->list);
|
| 527 | copy_siginfo(info, &first->info);
|
| 528 | __sigqueue_free(first);
|
| 529 | } else {
|
| 530 | |
| 531 | * Ok, it wasn't in the queue. This must be
|
| 532 | * a fast-pathed signal or we must have been
|
| 533 | * out of queue space. So zero out the info.
|
| 534 |
|
| 535 | info->si_signo = sig;
|
| 536 | info->si_errno = 0;
|
| 537 | info->si_code = SI_USER;
|
| 538 | info->si_pid = 0;
|
| 539 | info->si_uid = 0;
|
| 540 | }
|
| 541 | }
|
| 542 |
|
| 543 | static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
|
| 544 | siginfo_t *info)
|
| 545 | {
|
| 546 | int sig = next_signal(pending, mask);
|
| 547 |
|
| 548 | if (sig)
|
| 549 | collect_signal(sig, pending, info);
|
| 550 | return sig;
|
| 551 | }
|
| 552 |
|
| 553 | |
| 554 | * Dequeue a signal and return the element to the caller, which is
|
| 555 | * expected to free it.
|
| 556 | *
|
| 557 | * All callers have to hold the siglock.
|
| 558 |
|
| 559 | int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
|
| 560 | {
|
| 561 | int signr;
|
| 562 |
|
| 563 | |
| 564 | * signalfd steal them
|
| 565 |
|
| 566 | signr = __dequeue_signal(&tsk->pending, mask, info);
|
| 567 | if (!signr) {
|
| 568 | signr = __dequeue_signal(&tsk->signal->shared_pending,
|
| 569 | mask, info);
|
| 570 | |
| 571 | * itimer signal ?
|
| 572 | *
|
| 573 | * itimers are process shared and we restart periodic
|
| 574 | * itimers in the signal delivery path to prevent DoS
|
| 575 | * attacks in the high resolution timer case. This is
|
| 576 | * compliant with the old way of self-restarting
|
| 577 | * itimers, as the SIGALRM is a legacy signal and only
|
| 578 | * queued once. Changing the restart behaviour to
|
| 579 | * restart the timer in the signal dequeue path is
|
| 580 | * reducing the timer noise on heavy loaded !highres
|
| 581 | * systems too.
|
| 582 |
|
| 583 | if (unlikely(signr == SIGALRM)) {
|
| 584 | struct hrtimer *tmr = &tsk->signal->real_timer;
|
| 585 |
|
| 586 | if (!hrtimer_is_queued(tmr) &&
|
| 587 | tsk->signal->it_real_incr.tv64 != 0) {
|
| 588 | hrtimer_forward(tmr, tmr->base->get_time(),
|
| 589 | tsk->signal->it_real_incr);
|
| 590 | hrtimer_restart(tmr);
|
| 591 | }
|
| 592 | }
|
| 593 | }
|
| 594 |
|
| 595 | recalc_sigpending();
|
| 596 | if (!signr)
|
| 597 | return 0;
|
| 598 |
|
| 599 | if (unlikely(sig_kernel_stop(signr))) {
|
| 600 | |
| 601 | * Set a marker that we have dequeued a stop signal. Our
|
| 602 | * caller might release the siglock and then the pending
|
| 603 | * stop signal it is about to process is no longer in the
|
| 604 | * pending bitmasks, but must still be cleared by a SIGCONT
|
| 605 | * (and overruled by a SIGKILL). So those cases clear this
|
| 606 | * shared flag after we've set it. Note that this flag may
|
| 607 | * remain set after the signal we return is ignored or
|
| 608 | * handled. That doesn't matter because its only purpose
|
| 609 | * is to alert stop-signal processing code when another
|
| 610 | * processor has come along and cleared the flag.
|
| 611 |
|
| 612 | current->jobctl |= JOBCTL_STOP_DEQUEUED;
|
| 613 | }
|
| 614 | if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) {
|
| 615 | |
| 616 | * Release the siglock to ensure proper locking order
|
| 617 | * of timer locks outside of siglocks. Note, we leave
|
| 618 | * irqs disabled here, since the posix-timers code is
|
| 619 | * about to disable them again anyway.
|
| 620 |
|
| 621 | spin_unlock(&tsk->sighand->siglock);
|
| 622 | do_schedule_next_timer(info);
|
| 623 | spin_lock(&tsk->sighand->siglock);
|
| 624 | }
|
| 625 | return signr;
|
| 626 | }
|
| 627 |
|
| 628 | |
| 629 | * Tell a process that it has a new active signal..
|
| 630 | *
|
| 631 | * NOTE! we rely on the previous spin_lock to
|
| 632 | * lock interrupts for us! We can only be called with
|
| 633 | * "siglock" held, and the local interrupt must
|
| 634 | * have been disabled when that got acquired!
|
| 635 | *
|
| 636 | * No need to set need_resched since signal event passing
|
| 637 | * goes through ->blocked
|
| 638 |
|
| 639 | void signal_wake_up_state(struct task_struct *t, unsigned int state)
|
| 640 | {
|
| 641 | set_tsk_thread_flag(t, TIF_SIGPENDING);
|
| 642 | |
| 643 | * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
|
| 644 | * case. We don't check t->state here because there is a race with it
|
| 645 | * executing another processor and just now entering stopped state.
|
| 646 | * By using wake_up_state, we ensure the process will wake up and
|
| 647 | * handle its death signal.
|
| 648 |
|
| 649 | if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
|
| 650 | kick_process(t);
|
| 651 | }
|
| 652 |
|
| 653 | |
| 654 | * Remove signals in mask from the pending set and queue.
|
| 655 | * Returns 1 if any signals were found.
|
| 656 | *
|
| 657 | * All callers must be holding the siglock.
|
| 658 |
|
| 659 | static int flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
|
| 660 | {
|
| 661 | struct sigqueue *q, *n;
|
| 662 | sigset_t m;
|
| 663 |
|
| 664 | sigandsets(&m, mask, &s->signal);
|
| 665 | if (sigisemptyset(&m))
|
| 666 | return 0;
|
| 667 |
|
| 668 | sigandnsets(&s->signal, &s->signal, mask);
|
| 669 | list_for_each_entry_safe(q, n, &s->list, list) {
|
| 670 | if (sigismember(mask, q->info.si_signo)) {
|
| 671 | list_del_init(&q->list);
|
| 672 | __sigqueue_free(q);
|
| 673 | }
|
| 674 | }
|
| 675 | return 1;
|
| 676 | }
|
| 677 |
|
| 678 | static inline int is_si_special(const struct siginfo *info)
|
| 679 | {
|
| 680 | return info <= SEND_SIG_FORCED;
|
| 681 | }
|
| 682 |
|
| 683 | static inline bool si_fromuser(const struct siginfo *info)
|
| 684 | {
|
| 685 | return info == SEND_SIG_NOINFO ||
|
| 686 | (!is_si_special(info) && SI_FROMUSER(info));
|
| 687 | }
|
| 688 |
|
| 689 | |
| 690 | * called with RCU read lock from check_kill_permission()
|
| 691 |
|
| 692 | static int kill_ok_by_cred(struct task_struct *t)
|
| 693 | {
|
| 694 | const struct cred *cred = current_cred();
|
| 695 | const struct cred *tcred = __task_cred(t);
|
| 696 |
|
| 697 | if (uid_eq(cred->euid, tcred->suid) ||
|
| 698 | uid_eq(cred->euid, tcred->uid) ||
|
| 699 | uid_eq(cred->uid, tcred->suid) ||
|
| 700 | uid_eq(cred->uid, tcred->uid))
|
| 701 | return 1;
|
| 702 |
|
| 703 | if (ns_capable(tcred->user_ns, CAP_KILL))
|
| 704 | return 1;
|
| 705 |
|
| 706 | return 0;
|
| 707 | }
|
| 708 |
|
| 709 | |
| 710 | * Bad permissions for sending the signal
|
| 711 | * - the caller must hold the RCU read lock
|
| 712 |
|
| 713 | static int check_kill_permission(int sig, struct siginfo *info,
|
| 714 | struct task_struct *t)
|
| 715 | {
|
| 716 | struct pid *sid;
|
| 717 | int error;
|
| 718 |
|
| 719 | if (!valid_signal(sig))
|
| 720 | return -EINVAL;
|
| 721 |
|
| 722 | if (!si_fromuser(info))
|
| 723 | return 0;
|
| 724 |
|
| 725 | error = audit_signal_info(sig, t);
|
| 726 | if (error)
|
| 727 | return error;
|
| 728 |
|
| 729 | if (!same_thread_group(current, t) &&
|
| 730 | !kill_ok_by_cred(t)) {
|
| 731 | switch (sig) {
|
| 732 | case SIGCONT:
|
| 733 | sid = task_session(t);
|
| 734 | |
| 735 | * We don't return the error if sid == NULL. The
|
| 736 | * task was unhashed, the caller must notice this.
|
| 737 |
|
| 738 | if (!sid || sid == task_session(current))
|
| 739 | break;
|
| 740 | default:
|
| 741 | return -EPERM;
|
| 742 | }
|
| 743 | }
|
| 744 |
|
| 745 | return security_task_kill(t, info, sig, 0);
|
| 746 | }
|
| 747 |
|
| 748 | |
| 749 | * ptrace_trap_notify - schedule trap to notify ptracer
|
| 750 | * @t: tracee wanting to notify tracer
|
| 751 | *
|
| 752 | * This function schedules sticky ptrace trap which is cleared on the next
|
| 753 | * TRAP_STOP to notify ptracer of an event. @t must have been seized by
|
| 754 | * ptracer.
|
| 755 | *
|
| 756 | * If @t is running, STOP trap will be taken. If trapped for STOP and
|
| 757 | * ptracer is listening for events, tracee is woken up so that it can
|
| 758 | * re-trap for the new event. If trapped otherwise, STOP trap will be
|
| 759 | * eventually taken without returning to userland after the existing traps
|
| 760 | * are finished by PTRACE_CONT.
|
| 761 | *
|
| 762 | * CONTEXT:
|
| 763 | * Must be called with @task->sighand->siglock held.
|
| 764 |
|
| 765 | static void ptrace_trap_notify(struct task_struct *t)
|
| 766 | {
|
| 767 | WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
|
| 768 | assert_spin_locked(&t->sighand->siglock);
|
| 769 |
|
| 770 | task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
|
| 771 | ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
|
| 772 | }
|
| 773 |
|
| 774 | |
| 775 | * Handle magic process-wide effects of stop/continue signals. Unlike
|
| 776 | * the signal actions, these happen immediately at signal-generation
|
| 777 | * time regardless of blocking, ignoring, or handling. This does the
|
| 778 | * actual continuing for SIGCONT, but not the actual stopping for stop
|
| 779 | * signals. The process stop is done as a signal action for SIG_DFL.
|
| 780 | *
|
| 781 | * Returns true if the signal should be actually delivered, otherwise
|
| 782 | * it should be dropped.
|
| 783 |
|
| 784 | static bool prepare_signal(int sig, struct task_struct *p, bool force)
|
| 785 | {
|
| 786 | struct signal_struct *signal = p->signal;
|
| 787 | struct task_struct *t;
|
| 788 | sigset_t flush;
|
| 789 |
|
| 790 | if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) {
|
| 791 | if (!(signal->flags & SIGNAL_GROUP_EXIT))
|
| 792 | return sig == SIGKILL;
|
| 793 | |
| 794 | * The process is in the middle of dying, nothing to do.
|
| 795 |
|
| 796 | } else if (sig_kernel_stop(sig)) {
|
| 797 | |
| 798 | * This is a stop signal. Remove SIGCONT from all queues.
|
| 799 |
|
| 800 | siginitset(&flush, sigmask(SIGCONT));
|
| 801 | flush_sigqueue_mask(&flush, &signal->shared_pending);
|
| 802 | for_each_thread(p, t)
|
| 803 | flush_sigqueue_mask(&flush, &t->pending);
|
| 804 | } else if (sig == SIGCONT) {
|
| 805 | unsigned int why;
|
| 806 | |
| 807 | * Remove all stop signals from all queues, wake all threads.
|
| 808 |
|
| 809 | siginitset(&flush, SIG_KERNEL_STOP_MASK);
|
| 810 | flush_sigqueue_mask(&flush, &signal->shared_pending);
|
| 811 | for_each_thread(p, t) {
|
| 812 | flush_sigqueue_mask(&flush, &t->pending);
|
| 813 | task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
|
| 814 | if (likely(!(t->ptrace & PT_SEIZED)))
|
| 815 | wake_up_state(t, __TASK_STOPPED);
|
| 816 | else
|
| 817 | ptrace_trap_notify(t);
|
| 818 | }
|
| 819 |
|
| 820 | |
| 821 | * Notify the parent with CLD_CONTINUED if we were stopped.
|
| 822 | *
|
| 823 | * If we were in the middle of a group stop, we pretend it
|
| 824 | * was already finished, and then continued. Since SIGCHLD
|
| 825 | * doesn't queue we report only CLD_STOPPED, as if the next
|
| 826 | * CLD_CONTINUED was dropped.
|
| 827 |
|
| 828 | why = 0;
|
| 829 | if (signal->flags & SIGNAL_STOP_STOPPED)
|
| 830 | why |= SIGNAL_CLD_CONTINUED;
|
| 831 | else if (signal->group_stop_count)
|
| 832 | why |= SIGNAL_CLD_STOPPED;
|
| 833 |
|
| 834 | if (why) {
|
| 835 | |
| 836 | * The first thread which returns from do_signal_stop()
|
| 837 | * will take ->siglock, notice SIGNAL_CLD_MASK, and
|
| 838 | * notify its parent. See get_signal_to_deliver().
|
| 839 |
|
| 840 | signal->flags = why | SIGNAL_STOP_CONTINUED;
|
| 841 | signal->group_stop_count = 0;
|
| 842 | signal->group_exit_code = 0;
|
| 843 | }
|
| 844 | }
|
| 845 |
|
| 846 | return !sig_ignored(p, sig, force);
|
| 847 | }
|
| 848 |
|
| 849 | |
| 850 | * Test if P wants to take SIG. After we've checked all threads with this,
|
| 851 | * it's equivalent to finding no threads not blocking SIG. Any threads not
|
| 852 | * blocking SIG were ruled out because they are not running and already
|
| 853 | * have pending signals. Such threads will dequeue from the shared queue
|
| 854 | * as soon as they're available, so putting the signal on the shared queue
|
| 855 | * will be equivalent to sending it to one such thread.
|
| 856 |
|
| 857 | static inline int wants_signal(int sig, struct task_struct *p)
|
| 858 | {
|
| 859 | if (sigismember(&p->blocked, sig))
|
| 860 | return 0;
|
| 861 | if (p->flags & PF_EXITING)
|
| 862 | return 0;
|
| 863 | if (sig == SIGKILL)
|
| 864 | return 1;
|
| 865 | if (task_is_stopped_or_traced(p))
|
| 866 | return 0;
|
| 867 | return task_curr(p) || !signal_pending(p);
|
| 868 | }
|
| 869 |
|
| 870 | static void complete_signal(int sig, struct task_struct *p, int group)
|
| 871 | {
|
| 872 | struct signal_struct *signal = p->signal;
|
| 873 | struct task_struct *t;
|
| 874 |
|
| 875 | |
| 876 | * Now find a thread we can wake up to take the signal off the queue.
|
| 877 | *
|
| 878 | * If the main thread wants the signal, it gets first crack.
|
| 879 | * Probably the least surprising to the average bear.
|
| 880 |
|
| 881 | if (wants_signal(sig, p))
|
| 882 | t = p;
|
| 883 | else if (!group || thread_group_empty(p))
|
| 884 | |
| 885 | * There is just one thread and it does not need to be woken.
|
| 886 | * It will dequeue unblocked signals before it runs again.
|
| 887 |
|
| 888 | return;
|
| 889 | else {
|
| 890 | |
| 891 | * Otherwise try to find a suitable thread.
|
| 892 |
|
| 893 | t = signal->curr_target;
|
| 894 | while (!wants_signal(sig, t)) {
|
| 895 | t = next_thread(t);
|
| 896 | if (t == signal->curr_target)
|
| 897 | |
| 898 | * No thread needs to be woken.
|
| 899 | * Any eligible threads will see
|
| 900 | * the signal in the queue soon.
|
| 901 |
|
| 902 | return;
|
| 903 | }
|
| 904 | signal->curr_target = t;
|
| 905 | }
|
| 906 |
|
| 907 | |
| 908 | * Found a killable thread. If the signal will be fatal,
|
| 909 | * then start taking the whole group down immediately.
|
| 910 |
|
| 911 | if (sig_fatal(p, sig) &&
|
| 912 | !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) &&
|
| 913 | !sigismember(&t->real_blocked, sig) &&
|
| 914 | (sig == SIGKILL || !t->ptrace)) {
|
| 915 | |
| 916 | * This signal will be fatal to the whole group.
|
| 917 |
|
| 918 | if (!sig_kernel_coredump(sig)) {
|
| 919 | |
| 920 | * Start a group exit and wake everybody up.
|
| 921 | * This way we don't have other threads
|
| 922 | * running and doing things after a slower
|
| 923 | * thread has the fatal signal pending.
|
| 924 |
|
| 925 | signal->flags = SIGNAL_GROUP_EXIT;
|
| 926 | signal->group_exit_code = sig;
|
| 927 | signal->group_stop_count = 0;
|
| 928 | t = p;
|
| 929 | do {
|
| 930 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
|
| 931 | sigaddset(&t->pending.signal, SIGKILL);
|
| 932 | signal_wake_up(t, 1);
|
| 933 | } while_each_thread(p, t);
|
| 934 | return;
|
| 935 | }
|
| 936 | }
|
| 937 |
|
| 938 | |
| 939 | * The signal is already in the shared-pending queue.
|
| 940 | * Tell the chosen thread to wake up and dequeue it.
|
| 941 |
|
| 942 | signal_wake_up(t, sig == SIGKILL);
|
| 943 | return;
|
| 944 | }
|
| 945 |
|
| 946 | static inline int legacy_queue(struct sigpending *signals, int sig)
|
| 947 | {
|
| 948 | return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
|
| 949 | }
|
| 950 |
|
| 951 | #ifdef CONFIG_USER_NS
|
| 952 | static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t)
|
| 953 | {
|
| 954 | if (current_user_ns() == task_cred_xxx(t, user_ns))
|
| 955 | return;
|
| 956 |
|
| 957 | if (SI_FROMKERNEL(info))
|
| 958 | return;
|
| 959 |
|
| 960 | rcu_read_lock();
|
| 961 | info->si_uid = from_kuid_munged(task_cred_xxx(t, user_ns),
|
| 962 | make_kuid(current_user_ns(), info->si_uid));
|
| 963 | rcu_read_unlock();
|
| 964 | }
|
| 965 | #else
|
| 966 | static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t)
|
| 967 | {
|
| 968 | return;
|
| 969 | }
|
| 970 | #endif
|
| 971 |
|
| 972 | static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
|
| 973 | int group, int from_ancestor_ns)
|
| 974 | {
|
| 975 | struct sigpending *pending;
|
| 976 | struct sigqueue *q;
|
| 977 | int override_rlimit;
|
| 978 | int ret = 0, result;
|
| 979 |
|
| 980 | assert_spin_locked(&t->sighand->siglock);
|
| 981 |
|
| 982 | result = TRACE_SIGNAL_IGNORED;
|
| 983 | if (!prepare_signal(sig, t,
|
| 984 | from_ancestor_ns || (info == SEND_SIG_FORCED)))
|
| 985 | goto ret;
|
| 986 |
|
| 987 | pending = group ? &t->signal->shared_pending : &t->pending;
|
| 988 | |
| 989 | * Short-circuit ignored signals and support queuing
|
| 990 | * exactly one non-rt signal, so that we can get more
|
| 991 | * detailed information about the cause of the signal.
|
| 992 |
|
| 993 | result = TRACE_SIGNAL_ALREADY_PENDING;
|
| 994 | if (legacy_queue(pending, sig))
|
| 995 | goto ret;
|
| 996 |
|
| 997 | result = TRACE_SIGNAL_DELIVERED;
|
| 998 | |
| 999 | * fast-pathed signals for kernel-internal things like SIGSTOP
|
| 1000 | * or SIGKILL.
|
| 1001 |
|
| 1002 | if (info == SEND_SIG_FORCED)
|
| 1003 | goto out_set;
|
| 1004 |
|
| 1005 | |
| 1006 | * Real-time signals must be queued if sent by sigqueue, or
|
| 1007 | * some other real-time mechanism. It is implementation
|
| 1008 | * defined whether kill() does so. We attempt to do so, on
|
| 1009 | * the principle of least surprise, but since kill is not
|
| 1010 | * allowed to fail with EAGAIN when low on memory we just
|
| 1011 | * make sure at least one signal gets delivered and don't
|
| 1012 | * pass on the info struct.
|
| 1013 |
|
| 1014 | if (sig < SIGRTMIN)
|
| 1015 | override_rlimit = (is_si_special(info) || info->si_code >= 0);
|
| 1016 | else
|
| 1017 | override_rlimit = 0;
|
| 1018 |
|
| 1019 | q = __sigqueue_alloc(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE,
|
| 1020 | override_rlimit);
|
| 1021 | if (q) {
|
| 1022 | list_add_tail(&q->list, &pending->list);
|
| 1023 | switch ((unsigned long) info) {
|
| 1024 | case (unsigned long) SEND_SIG_NOINFO:
|
| 1025 | q->info.si_signo = sig;
|
| 1026 | q->info.si_errno = 0;
|
| 1027 | q->info.si_code = SI_USER;
|
| 1028 | q->info.si_pid = task_tgid_nr_ns(current,
|
| 1029 | task_active_pid_ns(t));
|
| 1030 | q->info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
|
| 1031 | break;
|
| 1032 | case (unsigned long) SEND_SIG_PRIV:
|
| 1033 | q->info.si_signo = sig;
|
| 1034 | q->info.si_errno = 0;
|
| 1035 | q->info.si_code = SI_KERNEL;
|
| 1036 | q->info.si_pid = 0;
|
| 1037 | q->info.si_uid = 0;
|
| 1038 | break;
|
| 1039 | default:
|
| 1040 | copy_siginfo(&q->info, info);
|
| 1041 | if (from_ancestor_ns)
|
| 1042 | q->info.si_pid = 0;
|
| 1043 | break;
|
| 1044 | }
|
| 1045 |
|
| 1046 | userns_fixup_signal_uid(&q->info, t);
|
| 1047 |
|
| 1048 | } else if (!is_si_special(info)) {
|
| 1049 | if (sig >= SIGRTMIN && info->si_code != SI_USER) {
|
| 1050 | |
| 1051 | * Queue overflow, abort. We may abort if the
|
| 1052 | * signal was rt and sent by user using something
|
| 1053 | * other than kill().
|
| 1054 |
|
| 1055 | result = TRACE_SIGNAL_OVERFLOW_FAIL;
|
| 1056 | ret = -EAGAIN;
|
| 1057 | goto ret;
|
| 1058 | } else {
|
| 1059 | |
| 1060 | * This is a silent loss of information. We still
|
| 1061 | * send the signal, but the *info bits are lost.
|
| 1062 |
|
| 1063 | result = TRACE_SIGNAL_LOSE_INFO;
|
| 1064 | }
|
| 1065 | }
|
| 1066 |
|
| 1067 | out_set:
|
| 1068 | signalfd_notify(t, sig);
|
| 1069 | sigaddset(&pending->signal, sig);
|
| 1070 | complete_signal(sig, t, group);
|
| 1071 | ret:
|
| 1072 | trace_signal_generate(sig, info, t, group, result);
|
| 1073 | return ret;
|
| 1074 | }
|
| 1075 |
|
| 1076 | static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
|
| 1077 | int group)
|
| 1078 | {
|
| 1079 | int from_ancestor_ns = 0;
|
| 1080 |
|
| 1081 | #ifdef CONFIG_PID_NS
|
| 1082 | from_ancestor_ns = si_fromuser(info) &&
|
| 1083 | !task_pid_nr_ns(current, task_active_pid_ns(t));
|
| 1084 | #endif
|
| 1085 |
|
| 1086 | return __send_signal(sig, info, t, group, from_ancestor_ns);
|
| 1087 | }
|
| 1088 |
|
| 1089 | static void print_fatal_signal(int signr)
|
| 1090 | {
|
| 1091 | struct pt_regs *regs = signal_pt_regs();
|
| 1092 | pr_info("potentially unexpected fatal signal %d.\n", signr);
|
| 1093 |
|
| 1094 | #if defined(__i386__) && !defined(__arch_um__)
|
| 1095 | pr_info("code at %08lx: ", regs->ip);
|
| 1096 | {
|
| 1097 | int i;
|
| 1098 | for (i = 0; i < 16; i++) {
|
| 1099 | unsigned char insn;
|
| 1100 |
|
| 1101 | if (get_user(insn, (unsigned char *)(regs->ip + i)))
|
| 1102 | break;
|
| 1103 | pr_cont("%02x ", insn);
|
| 1104 | }
|
| 1105 | }
|
| 1106 | pr_cont("\n");
|
| 1107 | #endif
|
| 1108 | preempt_disable();
|
| 1109 | show_regs(regs);
|
| 1110 | preempt_enable();
|
| 1111 | }
|
| 1112 |
|
| 1113 | static int __init setup_print_fatal_signals(char *str)
|
| 1114 | {
|
| 1115 | get_option (&str, &print_fatal_signals);
|
| 1116 |
|
| 1117 | return 1;
|
| 1118 | }
|
| 1119 |
|
| 1120 | __setup("print-fatal-signals=", setup_print_fatal_signals);
|
| 1121 |
|
| 1122 | int
|
| 1123 | __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
|
| 1124 | {
|
| 1125 | return send_signal(sig, info, p, 1);
|
| 1126 | }
|
| 1127 |
|
| 1128 | static int
|
| 1129 | specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t)
|
| 1130 | {
|
| 1131 | return send_signal(sig, info, t, 0);
|
| 1132 | }
|
| 1133 |
|
| 1134 | int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p,
|
| 1135 | bool group)
|
| 1136 | {
|
| 1137 | unsigned long flags;
|
| 1138 | int ret = -ESRCH;
|
| 1139 |
|
| 1140 | if (lock_task_sighand(p, &flags)) {
|
| 1141 | ret = send_signal(sig, info, p, group);
|
| 1142 | unlock_task_sighand(p, &flags);
|
| 1143 | }
|
| 1144 |
|
| 1145 | return ret;
|
| 1146 | }
|
| 1147 |
|
| 1148 | |
| 1149 | * Force a signal that the process can't ignore: if necessary
|
| 1150 | * we unblock the signal and change any SIG_IGN to SIG_DFL.
|
| 1151 | *
|
| 1152 | * Note: If we unblock the signal, we always reset it to SIG_DFL,
|
| 1153 | * since we do not want to have a signal handler that was blocked
|
| 1154 | * be invoked when user space had explicitly blocked it.
|
| 1155 | *
|
| 1156 | * We don't want to have recursive SIGSEGV's etc, for example,
|
| 1157 | * that is why we also clear SIGNAL_UNKILLABLE.
|
| 1158 |
|
| 1159 | int
|
| 1160 | force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
|
| 1161 | {
|
| 1162 | unsigned long int flags;
|
| 1163 | int ret, blocked, ignored;
|
| 1164 | struct k_sigaction *action;
|
| 1165 |
|
| 1166 | spin_lock_irqsave(&t->sighand->siglock, flags);
|
| 1167 | action = &t->sighand->action[sig-1];
|
| 1168 | ignored = action->sa.sa_handler == SIG_IGN;
|
| 1169 | blocked = sigismember(&t->blocked, sig);
|
| 1170 | if (blocked || ignored) {
|
| 1171 | action->sa.sa_handler = SIG_DFL;
|
| 1172 | if (blocked) {
|
| 1173 | sigdelset(&t->blocked, sig);
|
| 1174 | recalc_sigpending_and_wake(t);
|
| 1175 | }
|
| 1176 | }
|
| 1177 | if (action->sa.sa_handler == SIG_DFL)
|
| 1178 | t->signal->flags &= ~SIGNAL_UNKILLABLE;
|
| 1179 | ret = specific_send_sig_info(sig, info, t);
|
| 1180 | spin_unlock_irqrestore(&t->sighand->siglock, flags);
|
| 1181 |
|
| 1182 | return ret;
|
| 1183 | }
|
| 1184 |
|
| 1185 | |
| 1186 | * Nuke all other threads in the group.
|
| 1187 |
|
| 1188 | int zap_other_threads(struct task_struct *p)
|
| 1189 | {
|
| 1190 | struct task_struct *t = p;
|
| 1191 | int count = 0;
|
| 1192 |
|
| 1193 | p->signal->group_stop_count = 0;
|
| 1194 |
|
| 1195 | while_each_thread(p, t) {
|
| 1196 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
|
| 1197 | count++;
|
| 1198 |
|
| 1199 |
|
| 1200 | if (t->exit_state)
|
| 1201 | continue;
|
| 1202 | sigaddset(&t->pending.signal, SIGKILL);
|
| 1203 | signal_wake_up(t, 1);
|
| 1204 | }
|
| 1205 |
|
| 1206 | return count;
|
| 1207 | }
|
| 1208 |
|
| 1209 | struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
|
| 1210 | unsigned long *flags)
|
| 1211 | {
|
| 1212 | struct sighand_struct *sighand;
|
| 1213 |
|
| 1214 | for (;;) {
|
| 1215 | |
| 1216 | * Disable interrupts early to avoid deadlocks.
|
| 1217 | * See rcu_read_unlock() comment header for details.
|
| 1218 |
|
| 1219 | local_irq_save(*flags);
|
| 1220 | rcu_read_lock();
|
| 1221 | sighand = rcu_dereference(tsk->sighand);
|
| 1222 | if (unlikely(sighand == NULL)) {
|
| 1223 | rcu_read_unlock();
|
| 1224 | local_irq_restore(*flags);
|
| 1225 | break;
|
| 1226 | }
|
| 1227 | |
| 1228 | * This sighand can be already freed and even reused, but
|
| 1229 | * we rely on SLAB_DESTROY_BY_RCU and sighand_ctor() which
|
| 1230 | * initializes ->siglock: this slab can't go away, it has
|
| 1231 | * the same object type, ->siglock can't be reinitialized.
|
| 1232 | *
|
| 1233 | * We need to ensure that tsk->sighand is still the same
|
| 1234 | * after we take the lock, we can race with de_thread() or
|
| 1235 | * __exit_signal(). In the latter case the next iteration
|
| 1236 | * must see ->sighand == NULL.
|
| 1237 |
|
| 1238 | spin_lock(&sighand->siglock);
|
| 1239 | if (likely(sighand == tsk->sighand)) {
|
| 1240 | rcu_read_unlock();
|
| 1241 | break;
|
| 1242 | }
|
| 1243 | spin_unlock(&sighand->siglock);
|
| 1244 | rcu_read_unlock();
|
| 1245 | local_irq_restore(*flags);
|
| 1246 | }
|
| 1247 |
|
| 1248 | return sighand;
|
| 1249 | }
|
| 1250 |
|
| 1251 | |
| 1252 | * send signal info to all the members of a group
|
| 1253 |
|
| 1254 | int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
|
| 1255 | {
|
| 1256 | int ret;
|
| 1257 |
|
| 1258 | rcu_read_lock();
|
| 1259 | ret = check_kill_permission(sig, info, p);
|
| 1260 | rcu_read_unlock();
|
| 1261 |
|
| 1262 | if (!ret && sig)
|
| 1263 | ret = do_send_sig_info(sig, info, p, true);
|
| 1264 |
|
| 1265 | return ret;
|
| 1266 | }
|
| 1267 |
|
| 1268 | |
| 1269 | * __kill_pgrp_info() sends a signal to a process group: this is what the tty
|
| 1270 | * control characters do (^C, ^Z etc)
|
| 1271 | * - the caller must hold at least a readlock on tasklist_lock
|
| 1272 |
|
| 1273 | int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp)
|
| 1274 | {
|
| 1275 | struct task_struct *p = NULL;
|
| 1276 | int retval, success;
|
| 1277 |
|
| 1278 | success = 0;
|
| 1279 | retval = -ESRCH;
|
| 1280 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
|
| 1281 | int err = group_send_sig_info(sig, info, p);
|
| 1282 | success |= !err;
|
| 1283 | retval = err;
|
| 1284 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
|
| 1285 | return success ? 0 : retval;
|
| 1286 | }
|
| 1287 |
|
| 1288 | int kill_pid_info(int sig, struct siginfo *info, struct pid *pid)
|
| 1289 | {
|
| 1290 | int error = -ESRCH;
|
| 1291 | struct task_struct *p;
|
| 1292 |
|
| 1293 | for (;;) {
|
| 1294 | rcu_read_lock();
|
| 1295 | p = pid_task(pid, PIDTYPE_PID);
|
| 1296 | if (p)
|
| 1297 | error = group_send_sig_info(sig, info, p);
|
| 1298 | rcu_read_unlock();
|
| 1299 | if (likely(!p || error != -ESRCH))
|
| 1300 | return error;
|
| 1301 |
|
| 1302 | |
| 1303 | * The task was unhashed in between, try again. If it
|
| 1304 | * is dead, pid_task() will return NULL, if we race with
|
| 1305 | * de_thread() it will find the new leader.
|
| 1306 |
|
| 1307 | }
|
| 1308 | }
|
| 1309 |
|
| 1310 | int kill_proc_info(int sig, struct siginfo *info, pid_t pid)
|
| 1311 | {
|
| 1312 | int error;
|
| 1313 | rcu_read_lock();
|
| 1314 | error = kill_pid_info(sig, info, find_vpid(pid));
|
| 1315 | rcu_read_unlock();
|
| 1316 | return error;
|
| 1317 | }
|
| 1318 |
|
| 1319 | static int kill_as_cred_perm(const struct cred *cred,
|
| 1320 | struct task_struct *target)
|
| 1321 | {
|
| 1322 | const struct cred *pcred = __task_cred(target);
|
| 1323 | if (!uid_eq(cred->euid, pcred->suid) && !uid_eq(cred->euid, pcred->uid) &&
|
| 1324 | !uid_eq(cred->uid, pcred->suid) && !uid_eq(cred->uid, pcred->uid))
|
| 1325 | return 0;
|
| 1326 | return 1;
|
| 1327 | }
|
| 1328 |
|
| 1329 |
|
| 1330 | int kill_pid_info_as_cred(int sig, struct siginfo *info, struct pid *pid,
|
| 1331 | const struct cred *cred, u32 secid)
|
| 1332 | {
|
| 1333 | int ret = -EINVAL;
|
| 1334 | struct task_struct *p;
|
| 1335 | unsigned long flags;
|
| 1336 |
|
| 1337 | if (!valid_signal(sig))
|
| 1338 | return ret;
|
| 1339 |
|
| 1340 | rcu_read_lock();
|
| 1341 | p = pid_task(pid, PIDTYPE_PID);
|
| 1342 | if (!p) {
|
| 1343 | ret = -ESRCH;
|
| 1344 | goto out_unlock;
|
| 1345 | }
|
| 1346 | if (si_fromuser(info) && !kill_as_cred_perm(cred, p)) {
|
| 1347 | ret = -EPERM;
|
| 1348 | goto out_unlock;
|
| 1349 | }
|
| 1350 | ret = security_task_kill(p, info, sig, secid);
|
| 1351 | if (ret)
|
| 1352 | goto out_unlock;
|
| 1353 |
|
| 1354 | if (sig) {
|
| 1355 | if (lock_task_sighand(p, &flags)) {
|
| 1356 | ret = __send_signal(sig, info, p, 1, 0);
|
| 1357 | unlock_task_sighand(p, &flags);
|
| 1358 | } else
|
| 1359 | ret = -ESRCH;
|
| 1360 | }
|
| 1361 | out_unlock:
|
| 1362 | rcu_read_unlock();
|
| 1363 | return ret;
|
| 1364 | }
|
| 1365 | EXPORT_SYMBOL_GPL(kill_pid_info_as_cred);
|
| 1366 |
|
| 1367 | |
| 1368 | * kill_something_info() interprets pid in interesting ways just like kill(2).
|
| 1369 | *
|
| 1370 | * POSIX specifies that kill(-1,sig) is unspecified, but what we have
|
| 1371 | * is probably wrong. Should make it like BSD or SYSV.
|
| 1372 |
|
| 1373 |
|
| 1374 | static int kill_something_info(int sig, struct siginfo *info, pid_t pid)
|
| 1375 | {
|
| 1376 | int ret;
|
| 1377 |
|
| 1378 | if (pid > 0) {
|
| 1379 | rcu_read_lock();
|
| 1380 | ret = kill_pid_info(sig, info, find_vpid(pid));
|
| 1381 | rcu_read_unlock();
|
| 1382 | return ret;
|
| 1383 | }
|
| 1384 |
|
| 1385 | read_lock(&tasklist_lock);
|
| 1386 | if (pid != -1) {
|
| 1387 | ret = __kill_pgrp_info(sig, info,
|
| 1388 | pid ? find_vpid(-pid) : task_pgrp(current));
|
| 1389 | } else {
|
| 1390 | int retval = 0, count = 0;
|
| 1391 | struct task_struct * p;
|
| 1392 |
|
| 1393 | for_each_process(p) {
|
| 1394 | if (task_pid_vnr(p) > 1 &&
|
| 1395 | !same_thread_group(p, current)) {
|
| 1396 | int err = group_send_sig_info(sig, info, p);
|
| 1397 | ++count;
|
| 1398 | if (err != -EPERM)
|
| 1399 | retval = err;
|
| 1400 | }
|
| 1401 | }
|
| 1402 | ret = count ? retval : -ESRCH;
|
| 1403 | }
|
| 1404 | read_unlock(&tasklist_lock);
|
| 1405 |
|
| 1406 | return ret;
|
| 1407 | }
|
| 1408 |
|
| 1409 | |
| 1410 | * These are for backward compatibility with the rest of the kernel source.
|
| 1411 |
|
| 1412 |
|
| 1413 | int send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
|
| 1414 | {
|
| 1415 | |
| 1416 | * Make sure legacy kernel users don't send in bad values
|
| 1417 | * (normal paths check this in check_kill_permission).
|
| 1418 |
|
| 1419 | if (!valid_signal(sig))
|
| 1420 | return -EINVAL;
|
| 1421 |
|
| 1422 | return do_send_sig_info(sig, info, p, false);
|
| 1423 | }
|
| 1424 |
|
| 1425 | #define __si_special(priv) \
|
| 1426 | ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
|
| 1427 |
|
| 1428 | int
|
| 1429 | send_sig(int sig, struct task_struct *p, int priv)
|
| 1430 | {
|
| 1431 | return send_sig_info(sig, __si_special(priv), p);
|
| 1432 | }
|
| 1433 |
|
| 1434 | void
|
| 1435 | force_sig(int sig, struct task_struct *p)
|
| 1436 | {
|
| 1437 | force_sig_info(sig, SEND_SIG_PRIV, p);
|
| 1438 | }
|
| 1439 |
|
| 1440 | |
| 1441 | * When things go south during signal handling, we
|
| 1442 | * will force a SIGSEGV. And if the signal that caused
|
| 1443 | * the problem was already a SIGSEGV, we'll want to
|
| 1444 | * make sure we don't even try to deliver the signal..
|
| 1445 |
|
| 1446 | int
|
| 1447 | force_sigsegv(int sig, struct task_struct *p)
|
| 1448 | {
|
| 1449 | if (sig == SIGSEGV) {
|
| 1450 | unsigned long flags;
|
| 1451 | spin_lock_irqsave(&p->sighand->siglock, flags);
|
| 1452 | p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
|
| 1453 | spin_unlock_irqrestore(&p->sighand->siglock, flags);
|
| 1454 | }
|
| 1455 | force_sig(SIGSEGV, p);
|
| 1456 | return 0;
|
| 1457 | }
|
| 1458 |
|
| 1459 | int kill_pgrp(struct pid *pid, int sig, int priv)
|
| 1460 | {
|
| 1461 | int ret;
|
| 1462 |
|
| 1463 | read_lock(&tasklist_lock);
|
| 1464 | ret = __kill_pgrp_info(sig, __si_special(priv), pid);
|
| 1465 | read_unlock(&tasklist_lock);
|
| 1466 |
|
| 1467 | return ret;
|
| 1468 | }
|
| 1469 | EXPORT_SYMBOL(kill_pgrp);
|
| 1470 |
|
| 1471 | int kill_pid(struct pid *pid, int sig, int priv)
|
| 1472 | {
|
| 1473 | return kill_pid_info(sig, __si_special(priv), pid);
|
| 1474 | }
|
| 1475 | EXPORT_SYMBOL(kill_pid);
|
| 1476 |
|
| 1477 | |
| 1478 | * These functions support sending signals using preallocated sigqueue
|
| 1479 | * structures. This is needed "because realtime applications cannot
|
| 1480 | * afford to lose notifications of asynchronous events, like timer
|
| 1481 | * expirations or I/O completions". In the case of POSIX Timers
|
| 1482 | * we allocate the sigqueue structure from the timer_create. If this
|
| 1483 | * allocation fails we are able to report the failure to the application
|
| 1484 | * with an EAGAIN error.
|
| 1485 |
|
| 1486 | struct sigqueue *sigqueue_alloc(void)
|
| 1487 | {
|
| 1488 | struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
|
| 1489 |
|
| 1490 | if (q)
|
| 1491 | q->flags |= SIGQUEUE_PREALLOC;
|
| 1492 |
|
| 1493 | return q;
|
| 1494 | }
|
| 1495 |
|
| 1496 | void sigqueue_free(struct sigqueue *q)
|
| 1497 | {
|
| 1498 | unsigned long flags;
|
| 1499 | spinlock_t *lock = ¤t->sighand->siglock;
|
| 1500 |
|
| 1501 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
|
| 1502 | |
| 1503 | * We must hold ->siglock while testing q->list
|
| 1504 | * to serialize with collect_signal() or with
|
| 1505 | * __exit_signal()->flush_sigqueue().
|
| 1506 |
|
| 1507 | spin_lock_irqsave(lock, flags);
|
| 1508 | q->flags &= ~SIGQUEUE_PREALLOC;
|
| 1509 | |
| 1510 | * If it is queued it will be freed when dequeued,
|
| 1511 | * like the "regular" sigqueue.
|
| 1512 |
|
| 1513 | if (!list_empty(&q->list))
|
| 1514 | q = NULL;
|
| 1515 | spin_unlock_irqrestore(lock, flags);
|
| 1516 |
|
| 1517 | if (q)
|
| 1518 | __sigqueue_free(q);
|
| 1519 | }
|
| 1520 |
|
| 1521 | int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group)
|
| 1522 | {
|
| 1523 | int sig = q->info.si_signo;
|
| 1524 | struct sigpending *pending;
|
| 1525 | unsigned long flags;
|
| 1526 | int ret, result;
|
| 1527 |
|
| 1528 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
|
| 1529 |
|
| 1530 | ret = -1;
|
| 1531 | if (!likely(lock_task_sighand(t, &flags)))
|
| 1532 | goto ret;
|
| 1533 |
|
| 1534 | ret = 1;
|
| 1535 | result = TRACE_SIGNAL_IGNORED;
|
| 1536 | if (!prepare_signal(sig, t, false))
|
| 1537 | goto out;
|
| 1538 |
|
| 1539 | ret = 0;
|
| 1540 | if (unlikely(!list_empty(&q->list))) {
|
| 1541 | |
| 1542 | * If an SI_TIMER entry is already queue just increment
|
| 1543 | * the overrun count.
|
| 1544 |
|
| 1545 | BUG_ON(q->info.si_code != SI_TIMER);
|
| 1546 | q->info.si_overrun++;
|
| 1547 | result = TRACE_SIGNAL_ALREADY_PENDING;
|
| 1548 | goto out;
|
| 1549 | }
|
| 1550 | q->info.si_overrun = 0;
|
| 1551 |
|
| 1552 | signalfd_notify(t, sig);
|
| 1553 | pending = group ? &t->signal->shared_pending : &t->pending;
|
| 1554 | list_add_tail(&q->list, &pending->list);
|
| 1555 | sigaddset(&pending->signal, sig);
|
| 1556 | complete_signal(sig, t, group);
|
| 1557 | result = TRACE_SIGNAL_DELIVERED;
|
| 1558 | out:
|
| 1559 | trace_signal_generate(sig, &q->info, t, group, result);
|
| 1560 | unlock_task_sighand(t, &flags);
|
| 1561 | ret:
|
| 1562 | return ret;
|
| 1563 | }
|
| 1564 |
|
| 1565 | |
| 1566 | * Let a parent know about the death of a child.
|
| 1567 | * For a stopped/continued status change, use do_notify_parent_cldstop instead.
|
| 1568 | *
|
| 1569 | * Returns true if our parent ignored us and so we've switched to
|
| 1570 | * self-reaping.
|
| 1571 |
|
| 1572 | bool do_notify_parent(struct task_struct *tsk, int sig)
|
| 1573 | {
|
| 1574 | struct siginfo info;
|
| 1575 | unsigned long flags;
|
| 1576 | struct sighand_struct *psig;
|
| 1577 | bool autoreap = false;
|
| 1578 | cputime_t utime, stime;
|
| 1579 |
|
| 1580 | BUG_ON(sig == -1);
|
| 1581 |
|
| 1582 |
|
| 1583 | BUG_ON(task_is_stopped_or_traced(tsk));
|
| 1584 |
|
| 1585 | BUG_ON(!tsk->ptrace &&
|
| 1586 | (tsk->group_leader != tsk || !thread_group_empty(tsk)));
|
| 1587 |
|
| 1588 | if (sig != SIGCHLD) {
|
| 1589 | |
| 1590 | * This is only possible if parent == real_parent.
|
| 1591 | * Check if it has changed security domain.
|
| 1592 |
|
| 1593 | if (tsk->parent_exec_id != tsk->parent->self_exec_id)
|
| 1594 | sig = SIGCHLD;
|
| 1595 | }
|
| 1596 |
|
| 1597 | info.si_signo = sig;
|
| 1598 | info.si_errno = 0;
|
| 1599 | |
| 1600 | * We are under tasklist_lock here so our parent is tied to
|
| 1601 | * us and cannot change.
|
| 1602 | *
|
| 1603 | * task_active_pid_ns will always return the same pid namespace
|
| 1604 | * until a task passes through release_task.
|
| 1605 | *
|
| 1606 | * write_lock() currently calls preempt_disable() which is the
|
| 1607 | * same as rcu_read_lock(), but according to Oleg, this is not
|
| 1608 | * correct to rely on this
|
| 1609 |
|
| 1610 | rcu_read_lock();
|
| 1611 | info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
|
| 1612 | info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns),
|
| 1613 | task_uid(tsk));
|
| 1614 | rcu_read_unlock();
|
| 1615 |
|
| 1616 | task_cputime(tsk, &utime, &stime);
|
| 1617 | info.si_utime = cputime_to_clock_t(utime + tsk->signal->utime);
|
| 1618 | info.si_stime = cputime_to_clock_t(stime + tsk->signal->stime);
|
| 1619 |
|
| 1620 | info.si_status = tsk->exit_code & 0x7f;
|
| 1621 | if (tsk->exit_code & 0x80)
|
| 1622 | info.si_code = CLD_DUMPED;
|
| 1623 | else if (tsk->exit_code & 0x7f)
|
| 1624 | info.si_code = CLD_KILLED;
|
| 1625 | else {
|
| 1626 | info.si_code = CLD_EXITED;
|
| 1627 | info.si_status = tsk->exit_code >> 8;
|
| 1628 | }
|
| 1629 |
|
| 1630 | psig = tsk->parent->sighand;
|
| 1631 | spin_lock_irqsave(&psig->siglock, flags);
|
| 1632 | if (!tsk->ptrace && sig == SIGCHLD &&
|
| 1633 | (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
|
| 1634 | (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
|
| 1635 | |
| 1636 | * We are exiting and our parent doesn't care. POSIX.1
|
| 1637 | * defines special semantics for setting SIGCHLD to SIG_IGN
|
| 1638 | * or setting the SA_NOCLDWAIT flag: we should be reaped
|
| 1639 | * automatically and not left for our parent's wait4 call.
|
| 1640 | * Rather than having the parent do it as a magic kind of
|
| 1641 | * signal handler, we just set this to tell do_exit that we
|
| 1642 | * can be cleaned up without becoming a zombie. Note that
|
| 1643 | * we still call __wake_up_parent in this case, because a
|
| 1644 | * blocked sys_wait4 might now return -ECHILD.
|
| 1645 | *
|
| 1646 | * Whether we send SIGCHLD or not for SA_NOCLDWAIT
|
| 1647 | * is implementation-defined: we do (if you don't want
|
| 1648 | * it, just use SIG_IGN instead).
|
| 1649 |
|
| 1650 | autoreap = true;
|
| 1651 | if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
|
| 1652 | sig = 0;
|
| 1653 | }
|
| 1654 | if (valid_signal(sig) && sig)
|
| 1655 | __group_send_sig_info(sig, &info, tsk->parent);
|
| 1656 | __wake_up_parent(tsk, tsk->parent);
|
| 1657 | spin_unlock_irqrestore(&psig->siglock, flags);
|
| 1658 |
|
| 1659 | return autoreap;
|
| 1660 | }
|
| 1661 |
|
| 1662 | |
| 1663 | * do_notify_parent_cldstop - notify parent of stopped/continued state change
|
| 1664 | * @tsk: task reporting the state change
|
| 1665 | * @for_ptracer: the notification is for ptracer
|
| 1666 | * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
|
| 1667 | *
|
| 1668 | * Notify @tsk's parent that the stopped/continued state has changed. If
|
| 1669 | * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
|
| 1670 | * If %true, @tsk reports to @tsk->parent which should be the ptracer.
|
| 1671 | *
|
| 1672 | * CONTEXT:
|
| 1673 | * Must be called with tasklist_lock at least read locked.
|
| 1674 |
|
| 1675 | static void do_notify_parent_cldstop(struct task_struct *tsk,
|
| 1676 | bool for_ptracer, int why)
|
| 1677 | {
|
| 1678 | struct siginfo info;
|
| 1679 | unsigned long flags;
|
| 1680 | struct task_struct *parent;
|
| 1681 | struct sighand_struct *sighand;
|
| 1682 | cputime_t utime, stime;
|
| 1683 |
|
| 1684 | if (for_ptracer) {
|
| 1685 | parent = tsk->parent;
|
| 1686 | } else {
|
| 1687 | tsk = tsk->group_leader;
|
| 1688 | parent = tsk->real_parent;
|
| 1689 | }
|
| 1690 |
|
| 1691 | info.si_signo = SIGCHLD;
|
| 1692 | info.si_errno = 0;
|
| 1693 | |
| 1694 | * see comment in do_notify_parent() about the following 4 lines
|
| 1695 |
|
| 1696 | rcu_read_lock();
|
| 1697 | info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
|
| 1698 | info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
|
| 1699 | rcu_read_unlock();
|
| 1700 |
|
| 1701 | task_cputime(tsk, &utime, &stime);
|
| 1702 | info.si_utime = cputime_to_clock_t(utime);
|
| 1703 | info.si_stime = cputime_to_clock_t(stime);
|
| 1704 |
|
| 1705 | info.si_code = why;
|
| 1706 | switch (why) {
|
| 1707 | case CLD_CONTINUED:
|
| 1708 | info.si_status = SIGCONT;
|
| 1709 | break;
|
| 1710 | case CLD_STOPPED:
|
| 1711 | info.si_status = tsk->signal->group_exit_code & 0x7f;
|
| 1712 | break;
|
| 1713 | case CLD_TRAPPED:
|
| 1714 | info.si_status = tsk->exit_code & 0x7f;
|
| 1715 | break;
|
| 1716 | default:
|
| 1717 | BUG();
|
| 1718 | }
|
| 1719 |
|
| 1720 | sighand = parent->sighand;
|
| 1721 | spin_lock_irqsave(&sighand->siglock, flags);
|
| 1722 | if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
|
| 1723 | !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
|
| 1724 | __group_send_sig_info(SIGCHLD, &info, parent);
|
| 1725 | |
| 1726 | * Even if SIGCHLD is not generated, we must wake up wait4 calls.
|
| 1727 |
|
| 1728 | __wake_up_parent(tsk, parent);
|
| 1729 | spin_unlock_irqrestore(&sighand->siglock, flags);
|
| 1730 | }
|
| 1731 |
|
| 1732 | static inline int may_ptrace_stop(void)
|
| 1733 | {
|
| 1734 | if (!likely(current->ptrace))
|
| 1735 | return 0;
|
| 1736 | |
| 1737 | * Are we in the middle of do_coredump?
|
| 1738 | * If so and our tracer is also part of the coredump stopping
|
| 1739 | * is a deadlock situation, and pointless because our tracer
|
| 1740 | * is dead so don't allow us to stop.
|
| 1741 | * If SIGKILL was already sent before the caller unlocked
|
| 1742 | * ->siglock we must see ->core_state != NULL. Otherwise it
|
| 1743 | * is safe to enter schedule().
|
| 1744 | *
|
| 1745 | * This is almost outdated, a task with the pending SIGKILL can't
|
| 1746 | * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported
|
| 1747 | * after SIGKILL was already dequeued.
|
| 1748 |
|
| 1749 | if (unlikely(current->mm->core_state) &&
|
| 1750 | unlikely(current->mm == current->parent->mm))
|
| 1751 | return 0;
|
| 1752 |
|
| 1753 | return 1;
|
| 1754 | }
|
| 1755 |
|
| 1756 | |
| 1757 | * Return non-zero if there is a SIGKILL that should be waking us up.
|
| 1758 | * Called with the siglock held.
|
| 1759 |
|
| 1760 | static int sigkill_pending(struct task_struct *tsk)
|
| 1761 | {
|
| 1762 | return sigismember(&tsk->pending.signal, SIGKILL) ||
|
| 1763 | sigismember(&tsk->signal->shared_pending.signal, SIGKILL);
|
| 1764 | }
|
| 1765 |
|
| 1766 | |
| 1767 | * This must be called with current->sighand->siglock held.
|
| 1768 | *
|
| 1769 | * This should be the path for all ptrace stops.
|
| 1770 | * We always set current->last_siginfo while stopped here.
|
| 1771 | * That makes it a way to test a stopped process for
|
| 1772 | * being ptrace-stopped vs being job-control-stopped.
|
| 1773 | *
|
| 1774 | * If we actually decide not to stop at all because the tracer
|
| 1775 | * is gone, we keep current->exit_code unless clear_code.
|
| 1776 |
|
| 1777 | static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
|
| 1778 | __releases(¤t->sighand->siglock)
|
| 1779 | __acquires(¤t->sighand->siglock)
|
| 1780 | {
|
| 1781 | bool gstop_done = false;
|
| 1782 |
|
| 1783 | if (arch_ptrace_stop_needed(exit_code, info)) {
|
| 1784 | |
| 1785 | * The arch code has something special to do before a
|
| 1786 | * ptrace stop. This is allowed to block, e.g. for faults
|
| 1787 | * on user stack pages. We can't keep the siglock while
|
| 1788 | * calling arch_ptrace_stop, so we must release it now.
|
| 1789 | * To preserve proper semantics, we must do this before
|
| 1790 | * any signal bookkeeping like checking group_stop_count.
|
| 1791 | * Meanwhile, a SIGKILL could come in before we retake the
|
| 1792 | * siglock. That must prevent us from sleeping in TASK_TRACED.
|
| 1793 | * So after regaining the lock, we must check for SIGKILL.
|
| 1794 |
|
| 1795 | spin_unlock_irq(¤t->sighand->siglock);
|
| 1796 | arch_ptrace_stop(exit_code, info);
|
| 1797 | spin_lock_irq(¤t->sighand->siglock);
|
| 1798 | if (sigkill_pending(current))
|
| 1799 | return;
|
| 1800 | }
|
| 1801 |
|
| 1802 | |
| 1803 | * We're committing to trapping. TRACED should be visible before
|
| 1804 | * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
|
| 1805 | * Also, transition to TRACED and updates to ->jobctl should be
|
| 1806 | * atomic with respect to siglock and should be done after the arch
|
| 1807 | * hook as siglock is released and regrabbed across it.
|
| 1808 |
|
| 1809 | set_current_state(TASK_TRACED);
|
| 1810 |
|
| 1811 | current->last_siginfo = info;
|
| 1812 | current->exit_code = exit_code;
|
| 1813 |
|
| 1814 | |
| 1815 | * If @why is CLD_STOPPED, we're trapping to participate in a group
|
| 1816 | * stop. Do the bookkeeping. Note that if SIGCONT was delievered
|
| 1817 | * across siglock relocks since INTERRUPT was scheduled, PENDING
|
| 1818 | * could be clear now. We act as if SIGCONT is received after
|
| 1819 | * TASK_TRACED is entered - ignore it.
|
| 1820 |
|
| 1821 | if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
|
| 1822 | gstop_done = task_participate_group_stop(current);
|
| 1823 |
|
| 1824 |
|
| 1825 | task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
|
| 1826 | if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
|
| 1827 | task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
|
| 1828 |
|
| 1829 |
|
| 1830 | task_clear_jobctl_trapping(current);
|
| 1831 |
|
| 1832 | spin_unlock_irq(¤t->sighand->siglock);
|
| 1833 | read_lock(&tasklist_lock);
|
| 1834 | if (may_ptrace_stop()) {
|
| 1835 | |
| 1836 | * Notify parents of the stop.
|
| 1837 | *
|
| 1838 | * While ptraced, there are two parents - the ptracer and
|
| 1839 | * the real_parent of the group_leader. The ptracer should
|
| 1840 | * know about every stop while the real parent is only
|
| 1841 | * interested in the completion of group stop. The states
|
| 1842 | * for the two don't interact with each other. Notify
|
| 1843 | * separately unless they're gonna be duplicates.
|
| 1844 |
|
| 1845 | do_notify_parent_cldstop(current, true, why);
|
| 1846 | if (gstop_done && ptrace_reparented(current))
|
| 1847 | do_notify_parent_cldstop(current, false, why);
|
| 1848 |
|
| 1849 | |
| 1850 | * Don't want to allow preemption here, because
|
| 1851 | * sys_ptrace() needs this task to be inactive.
|
| 1852 | *
|
| 1853 | * XXX: implement read_unlock_no_resched().
|
| 1854 |
|
| 1855 | preempt_disable();
|
| 1856 | read_unlock(&tasklist_lock);
|
| 1857 | preempt_enable_no_resched();
|
| 1858 | freezable_schedule();
|
| 1859 | } else {
|
| 1860 | |
| 1861 | * By the time we got the lock, our tracer went away.
|
| 1862 | * Don't drop the lock yet, another tracer may come.
|
| 1863 | *
|
| 1864 | * If @gstop_done, the ptracer went away between group stop
|
| 1865 | * completion and here. During detach, it would have set
|
| 1866 | * JOBCTL_STOP_PENDING on us and we'll re-enter
|
| 1867 | * TASK_STOPPED in do_signal_stop() on return, so notifying
|
| 1868 | * the real parent of the group stop completion is enough.
|
| 1869 |
|
| 1870 | if (gstop_done)
|
| 1871 | do_notify_parent_cldstop(current, false, why);
|
| 1872 |
|
| 1873 |
|
| 1874 | __set_current_state(TASK_RUNNING);
|
| 1875 | if (clear_code)
|
| 1876 | current->exit_code = 0;
|
| 1877 | read_unlock(&tasklist_lock);
|
| 1878 | }
|
| 1879 |
|
| 1880 | |
| 1881 | * We are back. Now reacquire the siglock before touching
|
| 1882 | * last_siginfo, so that we are sure to have synchronized with
|
| 1883 | * any signal-sending on another CPU that wants to examine it.
|
| 1884 |
|
| 1885 | spin_lock_irq(¤t->sighand->siglock);
|
| 1886 | current->last_siginfo = NULL;
|
| 1887 |
|
| 1888 |
|
| 1889 | current->jobctl &= ~JOBCTL_LISTENING;
|
| 1890 |
|
| 1891 | |
| 1892 | * Queued signals ignored us while we were stopped for tracing.
|
| 1893 | * So check for any that we should take before resuming user mode.
|
| 1894 | * This sets TIF_SIGPENDING, but never clears it.
|
| 1895 |
|
| 1896 | recalc_sigpending_tsk(current);
|
| 1897 | }
|
| 1898 |
|
| 1899 | static void ptrace_do_notify(int signr, int exit_code, int why)
|
| 1900 | {
|
| 1901 | siginfo_t info;
|
| 1902 |
|
| 1903 | memset(&info, 0, sizeof info);
|
| 1904 | info.si_signo = signr;
|
| 1905 | info.si_code = exit_code;
|
| 1906 | info.si_pid = task_pid_vnr(current);
|
| 1907 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
|
| 1908 |
|
| 1909 |
|
| 1910 | ptrace_stop(exit_code, why, 1, &info);
|
| 1911 | }
|
| 1912 |
|
| 1913 | void ptrace_notify(int exit_code)
|
| 1914 | {
|
| 1915 | BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
|
| 1916 | if (unlikely(current->task_works))
|
| 1917 | task_work_run();
|
| 1918 |
|
| 1919 | spin_lock_irq(¤t->sighand->siglock);
|
| 1920 | ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
|
| 1921 | spin_unlock_irq(¤t->sighand->siglock);
|
| 1922 | }
|
| 1923 |
|
| 1924 | |
| 1925 | * do_signal_stop - handle group stop for SIGSTOP and other stop signals
|
| 1926 | * @signr: signr causing group stop if initiating
|
| 1927 | *
|
| 1928 | * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
|
| 1929 | * and participate in it. If already set, participate in the existing
|
| 1930 | * group stop. If participated in a group stop (and thus slept), %true is
|
| 1931 | * returned with siglock released.
|
| 1932 | *
|
| 1933 | * If ptraced, this function doesn't handle stop itself. Instead,
|
| 1934 | * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
|
| 1935 | * untouched. The caller must ensure that INTERRUPT trap handling takes
|
| 1936 | * places afterwards.
|
| 1937 | *
|
| 1938 | * CONTEXT:
|
| 1939 | * Must be called with @current->sighand->siglock held, which is released
|
| 1940 | * on %true return.
|
| 1941 | *
|
| 1942 | * RETURNS:
|
| 1943 | * %false if group stop is already cancelled or ptrace trap is scheduled.
|
| 1944 | * %true if participated in group stop.
|
| 1945 |
|
| 1946 | static bool do_signal_stop(int signr)
|
| 1947 | __releases(¤t->sighand->siglock)
|
| 1948 | {
|
| 1949 | struct signal_struct *sig = current->signal;
|
| 1950 |
|
| 1951 | if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
|
| 1952 | unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
|
| 1953 | struct task_struct *t;
|
| 1954 |
|
| 1955 |
|
| 1956 | WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
|
| 1957 |
|
| 1958 | if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
|
| 1959 | unlikely(signal_group_exit(sig)))
|
| 1960 | return false;
|
| 1961 | |
| 1962 | * There is no group stop already in progress. We must
|
| 1963 | * initiate one now.
|
| 1964 | *
|
| 1965 | * While ptraced, a task may be resumed while group stop is
|
| 1966 | * still in effect and then receive a stop signal and
|
| 1967 | * initiate another group stop. This deviates from the
|
| 1968 | * usual behavior as two consecutive stop signals can't
|
| 1969 | * cause two group stops when !ptraced. That is why we
|
| 1970 | * also check !task_is_stopped(t) below.
|
| 1971 | *
|
| 1972 | * The condition can be distinguished by testing whether
|
| 1973 | * SIGNAL_STOP_STOPPED is already set. Don't generate
|
| 1974 | * group_exit_code in such case.
|
| 1975 | *
|
| 1976 | * This is not necessary for SIGNAL_STOP_CONTINUED because
|
| 1977 | * an intervening stop signal is required to cause two
|
| 1978 | * continued events regardless of ptrace.
|
| 1979 |
|
| 1980 | if (!(sig->flags & SIGNAL_STOP_STOPPED))
|
| 1981 | sig->group_exit_code = signr;
|
| 1982 |
|
| 1983 | sig->group_stop_count = 0;
|
| 1984 |
|
| 1985 | if (task_set_jobctl_pending(current, signr | gstop))
|
| 1986 | sig->group_stop_count++;
|
| 1987 |
|
| 1988 | t = current;
|
| 1989 | while_each_thread(current, t) {
|
| 1990 | |
| 1991 | * Setting state to TASK_STOPPED for a group
|
| 1992 | * stop is always done with the siglock held,
|
| 1993 | * so this check has no races.
|
| 1994 |
|
| 1995 | if (!task_is_stopped(t) &&
|
| 1996 | task_set_jobctl_pending(t, signr | gstop)) {
|
| 1997 | sig->group_stop_count++;
|
| 1998 | if (likely(!(t->ptrace & PT_SEIZED)))
|
| 1999 | signal_wake_up(t, 0);
|
| 2000 | else
|
| 2001 | ptrace_trap_notify(t);
|
| 2002 | }
|
| 2003 | }
|
| 2004 | }
|
| 2005 |
|
| 2006 | if (likely(!current->ptrace)) {
|
| 2007 | int notify = 0;
|
| 2008 |
|
| 2009 | |
| 2010 | * If there are no other threads in the group, or if there
|
| 2011 | * is a group stop in progress and we are the last to stop,
|
| 2012 | * report to the parent.
|
| 2013 |
|
| 2014 | if (task_participate_group_stop(current))
|
| 2015 | notify = CLD_STOPPED;
|
| 2016 |
|
| 2017 | __set_current_state(TASK_STOPPED);
|
| 2018 | spin_unlock_irq(¤t->sighand->siglock);
|
| 2019 |
|
| 2020 | |
| 2021 | * Notify the parent of the group stop completion. Because
|
| 2022 | * we're not holding either the siglock or tasklist_lock
|
| 2023 | * here, ptracer may attach inbetween; however, this is for
|
| 2024 | * group stop and should always be delivered to the real
|
| 2025 | * parent of the group leader. The new ptracer will get
|
| 2026 | * its notification when this task transitions into
|
| 2027 | * TASK_TRACED.
|
| 2028 |
|
| 2029 | if (notify) {
|
| 2030 | read_lock(&tasklist_lock);
|
| 2031 | do_notify_parent_cldstop(current, false, notify);
|
| 2032 | read_unlock(&tasklist_lock);
|
| 2033 | }
|
| 2034 |
|
| 2035 |
|
| 2036 | freezable_schedule();
|
| 2037 | return true;
|
| 2038 | } else {
|
| 2039 | |
| 2040 | * While ptraced, group stop is handled by STOP trap.
|
| 2041 | * Schedule it and let the caller deal with it.
|
| 2042 |
|
| 2043 | task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
|
| 2044 | return false;
|
| 2045 | }
|
| 2046 | }
|
| 2047 |
|
| 2048 | |
| 2049 | * do_jobctl_trap - take care of ptrace jobctl traps
|
| 2050 | *
|
| 2051 | * When PT_SEIZED, it's used for both group stop and explicit
|
| 2052 | * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
|
| 2053 | * accompanying siginfo. If stopped, lower eight bits of exit_code contain
|
| 2054 | * the stop signal; otherwise, %SIGTRAP.
|
| 2055 | *
|
| 2056 | * When !PT_SEIZED, it's used only for group stop trap with stop signal
|
| 2057 | * number as exit_code and no siginfo.
|
| 2058 | *
|
| 2059 | * CONTEXT:
|
| 2060 | * Must be called with @current->sighand->siglock held, which may be
|
| 2061 | * released and re-acquired before returning with intervening sleep.
|
| 2062 |
|
| 2063 | static void do_jobctl_trap(void)
|
| 2064 | {
|
| 2065 | struct signal_struct *signal = current->signal;
|
| 2066 | int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
|
| 2067 |
|
| 2068 | if (current->ptrace & PT_SEIZED) {
|
| 2069 | if (!signal->group_stop_count &&
|
| 2070 | !(signal->flags & SIGNAL_STOP_STOPPED))
|
| 2071 | signr = SIGTRAP;
|
| 2072 | WARN_ON_ONCE(!signr);
|
| 2073 | ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
|
| 2074 | CLD_STOPPED);
|
| 2075 | } else {
|
| 2076 | WARN_ON_ONCE(!signr);
|
| 2077 | ptrace_stop(signr, CLD_STOPPED, 0, NULL);
|
| 2078 | current->exit_code = 0;
|
| 2079 | }
|
| 2080 | }
|
| 2081 |
|
| 2082 | static int ptrace_signal(int signr, siginfo_t *info)
|
| 2083 | {
|
| 2084 | ptrace_signal_deliver();
|
| 2085 | |
| 2086 | * We do not check sig_kernel_stop(signr) but set this marker
|
| 2087 | * unconditionally because we do not know whether debugger will
|
| 2088 | * change signr. This flag has no meaning unless we are going
|
| 2089 | * to stop after return from ptrace_stop(). In this case it will
|
| 2090 | * be checked in do_signal_stop(), we should only stop if it was
|
| 2091 | * not cleared by SIGCONT while we were sleeping. See also the
|
| 2092 | * comment in dequeue_signal().
|
| 2093 |
|
| 2094 | current->jobctl |= JOBCTL_STOP_DEQUEUED;
|
| 2095 | ptrace_stop(signr, CLD_TRAPPED, 0, info);
|
| 2096 |
|
| 2097 |
|
| 2098 | signr = current->exit_code;
|
| 2099 | if (signr == 0)
|
| 2100 | return signr;
|
| 2101 |
|
| 2102 | current->exit_code = 0;
|
| 2103 |
|
| 2104 | |
| 2105 | * Update the siginfo structure if the signal has
|
| 2106 | * changed. If the debugger wanted something
|
| 2107 | * specific in the siginfo structure then it should
|
| 2108 | * have updated *info via PTRACE_SETSIGINFO.
|
| 2109 |
|
| 2110 | if (signr != info->si_signo) {
|
| 2111 | info->si_signo = signr;
|
| 2112 | info->si_errno = 0;
|
| 2113 | info->si_code = SI_USER;
|
| 2114 | rcu_read_lock();
|
| 2115 | info->si_pid = task_pid_vnr(current->parent);
|
| 2116 | info->si_uid = from_kuid_munged(current_user_ns(),
|
| 2117 | task_uid(current->parent));
|
| 2118 | rcu_read_unlock();
|
| 2119 | }
|
| 2120 |
|
| 2121 |
|
| 2122 | if (sigismember(¤t->blocked, signr)) {
|
| 2123 | specific_send_sig_info(signr, info, current);
|
| 2124 | signr = 0;
|
| 2125 | }
|
| 2126 |
|
| 2127 | return signr;
|
| 2128 | }
|
| 2129 |
|
| 2130 | int get_signal(struct ksignal *ksig)
|
| 2131 | {
|
| 2132 | struct sighand_struct *sighand = current->sighand;
|
| 2133 | struct signal_struct *signal = current->signal;
|
| 2134 | int signr;
|
| 2135 |
|
| 2136 | if (unlikely(current->task_works))
|
| 2137 | task_work_run();
|
| 2138 |
|
| 2139 | if (unlikely(uprobe_deny_signal()))
|
| 2140 | return 0;
|
| 2141 |
|
| 2142 | |
| 2143 | * Do this once, we can't return to user-mode if freezing() == T.
|
| 2144 | * do_signal_stop() and ptrace_stop() do freezable_schedule() and
|
| 2145 | * thus do not need another check after return.
|
| 2146 |
|
| 2147 | try_to_freeze();
|
| 2148 |
|
| 2149 | relock:
|
| 2150 | spin_lock_irq(&sighand->siglock);
|
| 2151 | |
| 2152 | * Every stopped thread goes here after wakeup. Check to see if
|
| 2153 | * we should notify the parent, prepare_signal(SIGCONT) encodes
|
| 2154 | * the CLD_ si_code into SIGNAL_CLD_MASK bits.
|
| 2155 |
|
| 2156 | if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
|
| 2157 | int why;
|
| 2158 |
|
| 2159 | if (signal->flags & SIGNAL_CLD_CONTINUED)
|
| 2160 | why = CLD_CONTINUED;
|
| 2161 | else
|
| 2162 | why = CLD_STOPPED;
|
| 2163 |
|
| 2164 | signal->flags &= ~SIGNAL_CLD_MASK;
|
| 2165 |
|
| 2166 | spin_unlock_irq(&sighand->siglock);
|
| 2167 |
|
| 2168 | |
| 2169 | * Notify the parent that we're continuing. This event is
|
| 2170 | * always per-process and doesn't make whole lot of sense
|
| 2171 | * for ptracers, who shouldn't consume the state via
|
| 2172 | * wait(2) either, but, for backward compatibility, notify
|
| 2173 | * the ptracer of the group leader too unless it's gonna be
|
| 2174 | * a duplicate.
|
| 2175 |
|
| 2176 | read_lock(&tasklist_lock);
|
| 2177 | do_notify_parent_cldstop(current, false, why);
|
| 2178 |
|
| 2179 | if (ptrace_reparented(current->group_leader))
|
| 2180 | do_notify_parent_cldstop(current->group_leader,
|
| 2181 | true, why);
|
| 2182 | read_unlock(&tasklist_lock);
|
| 2183 |
|
| 2184 | goto relock;
|
| 2185 | }
|
| 2186 |
|
| 2187 | for (;;) {
|
| 2188 | struct k_sigaction *ka;
|
| 2189 |
|
| 2190 | if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
|
| 2191 | do_signal_stop(0))
|
| 2192 | goto relock;
|
| 2193 |
|
| 2194 | if (unlikely(current->jobctl & JOBCTL_TRAP_MASK)) {
|
| 2195 | do_jobctl_trap();
|
| 2196 | spin_unlock_irq(&sighand->siglock);
|
| 2197 | goto relock;
|
| 2198 | }
|
| 2199 |
|
| 2200 | signr = dequeue_signal(current, ¤t->blocked, &ksig->info);
|
| 2201 |
|
| 2202 | if (!signr)
|
| 2203 | break;
|
| 2204 |
|
| 2205 | if (unlikely(current->ptrace) && signr != SIGKILL) {
|
| 2206 | signr = ptrace_signal(signr, &ksig->info);
|
| 2207 | if (!signr)
|
| 2208 | continue;
|
| 2209 | }
|
| 2210 |
|
| 2211 | ka = &sighand->action[signr-1];
|
| 2212 |
|
| 2213 |
|
| 2214 | trace_signal_deliver(signr, &ksig->info, ka);
|
| 2215 |
|
| 2216 | if (ka->sa.sa_handler == SIG_IGN)
|
| 2217 | continue;
|
| 2218 | if (ka->sa.sa_handler != SIG_DFL) {
|
| 2219 |
|
| 2220 | ksig->ka = *ka;
|
| 2221 |
|
| 2222 | if (ka->sa.sa_flags & SA_ONESHOT)
|
| 2223 | ka->sa.sa_handler = SIG_DFL;
|
| 2224 |
|
| 2225 | break;
|
| 2226 | }
|
| 2227 |
|
| 2228 | |
| 2229 | * Now we are doing the default action for this signal.
|
| 2230 |
|
| 2231 | if (sig_kernel_ignore(signr))
|
| 2232 | continue;
|
| 2233 |
|
| 2234 | |
| 2235 | * Global init gets no signals it doesn't want.
|
| 2236 | * Container-init gets no signals it doesn't want from same
|
| 2237 | * container.
|
| 2238 | *
|
| 2239 | * Note that if global/container-init sees a sig_kernel_only()
|
| 2240 | * signal here, the signal must have been generated internally
|
| 2241 | * or must have come from an ancestor namespace. In either
|
| 2242 | * case, the signal cannot be dropped.
|
| 2243 |
|
| 2244 | if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
|
| 2245 | !sig_kernel_only(signr))
|
| 2246 | continue;
|
| 2247 |
|
| 2248 | if (sig_kernel_stop(signr)) {
|
| 2249 | |
| 2250 | * The default action is to stop all threads in
|
| 2251 | * the thread group. The job control signals
|
| 2252 | * do nothing in an orphaned pgrp, but SIGSTOP
|
| 2253 | * always works. Note that siglock needs to be
|
| 2254 | * dropped during the call to is_orphaned_pgrp()
|
| 2255 | * because of lock ordering with tasklist_lock.
|
| 2256 | * This allows an intervening SIGCONT to be posted.
|
| 2257 | * We need to check for that and bail out if necessary.
|
| 2258 |
|
| 2259 | if (signr != SIGSTOP) {
|
| 2260 | spin_unlock_irq(&sighand->siglock);
|
| 2261 |
|
| 2262 |
|
| 2263 |
|
| 2264 | if (is_current_pgrp_orphaned())
|
| 2265 | goto relock;
|
| 2266 |
|
| 2267 | spin_lock_irq(&sighand->siglock);
|
| 2268 | }
|
| 2269 |
|
| 2270 | if (likely(do_signal_stop(ksig->info.si_signo))) {
|
| 2271 |
|
| 2272 | goto relock;
|
| 2273 | }
|
| 2274 |
|
| 2275 | |
| 2276 | * We didn't actually stop, due to a race
|
| 2277 | * with SIGCONT or something like that.
|
| 2278 |
|
| 2279 | continue;
|
| 2280 | }
|
| 2281 |
|
| 2282 | spin_unlock_irq(&sighand->siglock);
|
| 2283 |
|
| 2284 | |
| 2285 | * Anything else is fatal, maybe with a core dump.
|
| 2286 |
|
| 2287 | current->flags |= PF_SIGNALED;
|
| 2288 |
|
| 2289 | if (sig_kernel_coredump(signr)) {
|
| 2290 | if (print_fatal_signals)
|
| 2291 | print_fatal_signal(ksig->info.si_signo);
|
| 2292 | proc_coredump_connector(current);
|
| 2293 | |
| 2294 | * If it was able to dump core, this kills all
|
| 2295 | * other threads in the group and synchronizes with
|
| 2296 | * their demise. If we lost the race with another
|
| 2297 | * thread getting here, it set group_exit_code
|
| 2298 | * first and our do_group_exit call below will use
|
| 2299 | * that value and ignore the one we pass it.
|
| 2300 |
|
| 2301 | do_coredump(&ksig->info);
|
| 2302 | }
|
| 2303 |
|
| 2304 | |
| 2305 | * Death signals, no core dump.
|
| 2306 |
|
| 2307 | do_group_exit(ksig->info.si_signo);
|
| 2308 |
|
| 2309 | }
|
| 2310 | spin_unlock_irq(&sighand->siglock);
|
| 2311 |
|
| 2312 | ksig->sig = signr;
|
| 2313 | return ksig->sig > 0;
|
| 2314 | }
|
| 2315 |
|
| 2316 | |
| 2317 | * signal_delivered -
|
| 2318 | * @ksig: kernel signal struct
|
| 2319 | * @stepping: nonzero if debugger single-step or block-step in use
|
| 2320 | *
|
| 2321 | * This function should be called when a signal has successfully been
|
| 2322 | * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
|
| 2323 | * is always blocked, and the signal itself is blocked unless %SA_NODEFER
|
| 2324 | * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
|
| 2325 |
|
| 2326 | static void signal_delivered(struct ksignal *ksig, int stepping)
|
| 2327 | {
|
| 2328 | sigset_t blocked;
|
| 2329 |
|
| 2330 | |
| 2331 | saved sigmask was stored on the signal frame,
|
| 2332 | and will be restored by sigreturn. So we can
|
| 2333 | simply clear the restore sigmask flag.
|
| 2334 | clear_restore_sigmask();
|
| 2335 |
|
| 2336 | sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask);
|
| 2337 | if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
|
| 2338 | sigaddset(&blocked, ksig->sig);
|
| 2339 | set_current_blocked(&blocked);
|
| 2340 | tracehook_signal_handler(stepping);
|
| 2341 | }
|
| 2342 |
|
| 2343 | void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
|
| 2344 | {
|
| 2345 | if (failed)
|
| 2346 | force_sigsegv(ksig->sig, current);
|
| 2347 | else
|
| 2348 | signal_delivered(ksig, stepping);
|
| 2349 | }
|
| 2350 |
|
| 2351 | |
| 2352 | * It could be that complete_signal() picked us to notify about the
|
| 2353 | * group-wide signal. Other threads should be notified now to take
|
| 2354 | * the shared signals in @which since we will not.
|
| 2355 |
|
| 2356 | static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
|
| 2357 | {
|
| 2358 | sigset_t retarget;
|
| 2359 | struct task_struct *t;
|
| 2360 |
|
| 2361 | sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
|
| 2362 | if (sigisemptyset(&retarget))
|
| 2363 | return;
|
| 2364 |
|
| 2365 | t = tsk;
|
| 2366 | while_each_thread(tsk, t) {
|
| 2367 | if (t->flags & PF_EXITING)
|
| 2368 | continue;
|
| 2369 |
|
| 2370 | if (!has_pending_signals(&retarget, &t->blocked))
|
| 2371 | continue;
|
| 2372 |
|
| 2373 | sigandsets(&retarget, &retarget, &t->blocked);
|
| 2374 |
|
| 2375 | if (!signal_pending(t))
|
| 2376 | signal_wake_up(t, 0);
|
| 2377 |
|
| 2378 | if (sigisemptyset(&retarget))
|
| 2379 | break;
|
| 2380 | }
|
| 2381 | }
|
| 2382 |
|
| 2383 | void exit_signals(struct task_struct *tsk)
|
| 2384 | {
|
| 2385 | int group_stop = 0;
|
| 2386 | sigset_t unblocked;
|
| 2387 |
|
| 2388 | |
| 2389 | * @tsk is about to have PF_EXITING set - lock out users which
|
| 2390 | * expect stable threadgroup.
|
| 2391 |
|
| 2392 | threadgroup_change_begin(tsk);
|
| 2393 |
|
| 2394 | if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
|
| 2395 | tsk->flags |= PF_EXITING;
|
| 2396 | threadgroup_change_end(tsk);
|
| 2397 | return;
|
| 2398 | }
|
| 2399 |
|
| 2400 | spin_lock_irq(&tsk->sighand->siglock);
|
| 2401 | |
| 2402 | * From now this task is not visible for group-wide signals,
|
| 2403 | * see wants_signal(), do_signal_stop().
|
| 2404 |
|
| 2405 | tsk->flags |= PF_EXITING;
|
| 2406 |
|
| 2407 | threadgroup_change_end(tsk);
|
| 2408 |
|
| 2409 | if (!signal_pending(tsk))
|
| 2410 | goto out;
|
| 2411 |
|
| 2412 | unblocked = tsk->blocked;
|
| 2413 | signotset(&unblocked);
|
| 2414 | retarget_shared_pending(tsk, &unblocked);
|
| 2415 |
|
| 2416 | if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
|
| 2417 | task_participate_group_stop(tsk))
|
| 2418 | group_stop = CLD_STOPPED;
|
| 2419 | out:
|
| 2420 | spin_unlock_irq(&tsk->sighand->siglock);
|
| 2421 |
|
| 2422 | |
| 2423 | * If group stop has completed, deliver the notification. This
|
| 2424 | * should always go to the real parent of the group leader.
|
| 2425 |
|
| 2426 | if (unlikely(group_stop)) {
|
| 2427 | read_lock(&tasklist_lock);
|
| 2428 | do_notify_parent_cldstop(tsk, false, group_stop);
|
| 2429 | read_unlock(&tasklist_lock);
|
| 2430 | }
|
| 2431 | }
|
| 2432 |
|
| 2433 | EXPORT_SYMBOL(recalc_sigpending);
|
| 2434 | EXPORT_SYMBOL_GPL(dequeue_signal);
|
| 2435 | EXPORT_SYMBOL(flush_signals);
|
| 2436 | EXPORT_SYMBOL(force_sig);
|
| 2437 | EXPORT_SYMBOL(send_sig);
|
| 2438 | EXPORT_SYMBOL(send_sig_info);
|
| 2439 | EXPORT_SYMBOL(sigprocmask);
|
| 2440 |
|
| 2441 | |
| 2442 | * System call entry points.
|
| 2443 |
|
| 2444 |
|
| 2445 | |
| 2446 | * sys_restart_syscall - restart a system call
|
| 2447 |
|
| 2448 | SYSCALL_DEFINE0(restart_syscall)
|
| 2449 | {
|
| 2450 | struct restart_block *restart = ¤t->restart_block;
|
| 2451 | return restart->fn(restart);
|
| 2452 | }
|
| 2453 |
|
| 2454 | long do_no_restart_syscall(struct restart_block *param)
|
| 2455 | {
|
| 2456 | return -EINTR;
|
| 2457 | }
|
| 2458 |
|
| 2459 | static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
|
| 2460 | {
|
| 2461 | if (signal_pending(tsk) && !thread_group_empty(tsk)) {
|
| 2462 | sigset_t newblocked;
|
| 2463 |
|
| 2464 | sigandnsets(&newblocked, newset, ¤t->blocked);
|
| 2465 | retarget_shared_pending(tsk, &newblocked);
|
| 2466 | }
|
| 2467 | tsk->blocked = *newset;
|
| 2468 | recalc_sigpending();
|
| 2469 | }
|
| 2470 |
|
| 2471 | |
| 2472 | * set_current_blocked - change current->blocked mask
|
| 2473 | * @newset: new mask
|
| 2474 | *
|
| 2475 | * It is wrong to change ->blocked directly, this helper should be used
|
| 2476 | * to ensure the process can't miss a shared signal we are going to block.
|
| 2477 |
|
| 2478 | void set_current_blocked(sigset_t *newset)
|
| 2479 | {
|
| 2480 | sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
|
| 2481 | __set_current_blocked(newset);
|
| 2482 | }
|
| 2483 |
|
| 2484 | void __set_current_blocked(const sigset_t *newset)
|
| 2485 | {
|
| 2486 | struct task_struct *tsk = current;
|
| 2487 |
|
| 2488 | spin_lock_irq(&tsk->sighand->siglock);
|
| 2489 | __set_task_blocked(tsk, newset);
|
| 2490 | spin_unlock_irq(&tsk->sighand->siglock);
|
| 2491 | }
|
| 2492 |
|
| 2493 | |
| 2494 | * This is also useful for kernel threads that want to temporarily
|
| 2495 | * (or permanently) block certain signals.
|
| 2496 | *
|
| 2497 | * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
|
| 2498 | * interface happily blocks "unblockable" signals like SIGKILL
|
| 2499 | * and friends.
|
| 2500 |
|
| 2501 | int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
|
| 2502 | {
|
| 2503 | struct task_struct *tsk = current;
|
| 2504 | sigset_t newset;
|
| 2505 |
|
| 2506 |
|
| 2507 | if (oldset)
|
| 2508 | *oldset = tsk->blocked;
|
| 2509 |
|
| 2510 | switch (how) {
|
| 2511 | case SIG_BLOCK:
|
| 2512 | sigorsets(&newset, &tsk->blocked, set);
|
| 2513 | break;
|
| 2514 | case SIG_UNBLOCK:
|
| 2515 | sigandnsets(&newset, &tsk->blocked, set);
|
| 2516 | break;
|
| 2517 | case SIG_SETMASK:
|
| 2518 | newset = *set;
|
| 2519 | break;
|
| 2520 | default:
|
| 2521 | return -EINVAL;
|
| 2522 | }
|
| 2523 |
|
| 2524 | __set_current_blocked(&newset);
|
| 2525 | return 0;
|
| 2526 | }
|
| 2527 |
|
| 2528 | |
| 2529 | * sys_rt_sigprocmask - change the list of currently blocked signals
|
| 2530 | * @how: whether to add, remove, or set signals
|
| 2531 | * @nset: stores pending signals
|
| 2532 | * @oset: previous value of signal mask if non-null
|
| 2533 | * @sigsetsize: size of sigset_t type
|
| 2534 |
|
| 2535 | SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
|
| 2536 | sigset_t __user *, oset, size_t, sigsetsize)
|
| 2537 | {
|
| 2538 | sigset_t old_set, new_set;
|
| 2539 | int error;
|
| 2540 |
|
| 2541 |
|
| 2542 | if (sigsetsize != sizeof(sigset_t))
|
| 2543 | return -EINVAL;
|
| 2544 |
|
| 2545 | old_set = current->blocked;
|
| 2546 |
|
| 2547 | if (nset) {
|
| 2548 | if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
|
| 2549 | return -EFAULT;
|
| 2550 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
|
| 2551 |
|
| 2552 | error = sigprocmask(how, &new_set, NULL);
|
| 2553 | if (error)
|
| 2554 | return error;
|
| 2555 | }
|
| 2556 |
|
| 2557 | if (oset) {
|
| 2558 | if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
|
| 2559 | return -EFAULT;
|
| 2560 | }
|
| 2561 |
|
| 2562 | return 0;
|
| 2563 | }
|
| 2564 |
|
| 2565 | #ifdef CONFIG_COMPAT
|
| 2566 | COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
|
| 2567 | compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
|
| 2568 | {
|
| 2569 | #ifdef __BIG_ENDIAN
|
| 2570 | sigset_t old_set = current->blocked;
|
| 2571 |
|
| 2572 |
|
| 2573 | if (sigsetsize != sizeof(sigset_t))
|
| 2574 | return -EINVAL;
|
| 2575 |
|
| 2576 | if (nset) {
|
| 2577 | compat_sigset_t new32;
|
| 2578 | sigset_t new_set;
|
| 2579 | int error;
|
| 2580 | if (copy_from_user(&new32, nset, sizeof(compat_sigset_t)))
|
| 2581 | return -EFAULT;
|
| 2582 |
|
| 2583 | sigset_from_compat(&new_set, &new32);
|
| 2584 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
|
| 2585 |
|
| 2586 | error = sigprocmask(how, &new_set, NULL);
|
| 2587 | if (error)
|
| 2588 | return error;
|
| 2589 | }
|
| 2590 | if (oset) {
|
| 2591 | compat_sigset_t old32;
|
| 2592 | sigset_to_compat(&old32, &old_set);
|
| 2593 | if (copy_to_user(oset, &old32, sizeof(compat_sigset_t)))
|
| 2594 | return -EFAULT;
|
| 2595 | }
|
| 2596 | return 0;
|
| 2597 | #else
|
| 2598 | return sys_rt_sigprocmask(how, (sigset_t __user *)nset,
|
| 2599 | (sigset_t __user *)oset, sigsetsize);
|
| 2600 | #endif
|
| 2601 | }
|
| 2602 | #endif
|
| 2603 |
|
| 2604 | static int do_sigpending(void *set, unsigned long sigsetsize)
|
| 2605 | {
|
| 2606 | if (sigsetsize > sizeof(sigset_t))
|
| 2607 | return -EINVAL;
|
| 2608 |
|
| 2609 | spin_lock_irq(¤t->sighand->siglock);
|
| 2610 | sigorsets(set, ¤t->pending.signal,
|
| 2611 | ¤t->signal->shared_pending.signal);
|
| 2612 | spin_unlock_irq(¤t->sighand->siglock);
|
| 2613 |
|
| 2614 |
|
| 2615 | sigandsets(set, ¤t->blocked, set);
|
| 2616 | return 0;
|
| 2617 | }
|
| 2618 |
|
| 2619 | |
| 2620 | * sys_rt_sigpending - examine a pending signal that has been raised
|
| 2621 | * while blocked
|
| 2622 | * @uset: stores pending signals
|
| 2623 | * @sigsetsize: size of sigset_t type or larger
|
| 2624 |
|
| 2625 | SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
|
| 2626 | {
|
| 2627 | sigset_t set;
|
| 2628 | int err = do_sigpending(&set, sigsetsize);
|
| 2629 | if (!err && copy_to_user(uset, &set, sigsetsize))
|
| 2630 | err = -EFAULT;
|
| 2631 | return err;
|
| 2632 | }
|
| 2633 |
|
| 2634 | #ifdef CONFIG_COMPAT
|
| 2635 | COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
|
| 2636 | compat_size_t, sigsetsize)
|
| 2637 | {
|
| 2638 | #ifdef __BIG_ENDIAN
|
| 2639 | sigset_t set;
|
| 2640 | int err = do_sigpending(&set, sigsetsize);
|
| 2641 | if (!err) {
|
| 2642 | compat_sigset_t set32;
|
| 2643 | sigset_to_compat(&set32, &set);
|
| 2644 |
|
| 2645 | if (copy_to_user(uset, &set32, sigsetsize))
|
| 2646 | err = -EFAULT;
|
| 2647 | }
|
| 2648 | return err;
|
| 2649 | #else
|
| 2650 | return sys_rt_sigpending((sigset_t __user *)uset, sigsetsize);
|
| 2651 | #endif
|
| 2652 | }
|
| 2653 | #endif
|
| 2654 |
|
| 2655 | #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER
|
| 2656 |
|
| 2657 | int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from)
|
| 2658 | {
|
| 2659 | int err;
|
| 2660 |
|
| 2661 | if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t)))
|
| 2662 | return -EFAULT;
|
| 2663 | if (from->si_code < 0)
|
| 2664 | return __copy_to_user(to, from, sizeof(siginfo_t))
|
| 2665 | ? -EFAULT : 0;
|
| 2666 | |
| 2667 | * If you change siginfo_t structure, please be sure
|
| 2668 | * this code is fixed accordingly.
|
| 2669 | * Please remember to update the signalfd_copyinfo() function
|
| 2670 | * inside fs/signalfd.c too, in case siginfo_t changes.
|
| 2671 | * It should never copy any pad contained in the structure
|
| 2672 | * to avoid security leaks, but must copy the generic
|
| 2673 | * 3 ints plus the relevant union member.
|
| 2674 |
|
| 2675 | err = __put_user(from->si_signo, &to->si_signo);
|
| 2676 | err |= __put_user(from->si_errno, &to->si_errno);
|
| 2677 | err |= __put_user((short)from->si_code, &to->si_code);
|
| 2678 | switch (from->si_code & __SI_MASK) {
|
| 2679 | case __SI_KILL:
|
| 2680 | err |= __put_user(from->si_pid, &to->si_pid);
|
| 2681 | err |= __put_user(from->si_uid, &to->si_uid);
|
| 2682 | break;
|
| 2683 | case __SI_TIMER:
|
| 2684 | err |= __put_user(from->si_tid, &to->si_tid);
|
| 2685 | err |= __put_user(from->si_overrun, &to->si_overrun);
|
| 2686 | err |= __put_user(from->si_ptr, &to->si_ptr);
|
| 2687 | break;
|
| 2688 | case __SI_POLL:
|
| 2689 | err |= __put_user(from->si_band, &to->si_band);
|
| 2690 | err |= __put_user(from->si_fd, &to->si_fd);
|
| 2691 | break;
|
| 2692 | case __SI_FAULT:
|
| 2693 | err |= __put_user(from->si_addr, &to->si_addr);
|
| 2694 | #ifdef __ARCH_SI_TRAPNO
|
| 2695 | err |= __put_user(from->si_trapno, &to->si_trapno);
|
| 2696 | #endif
|
| 2697 | #ifdef BUS_MCEERR_AO
|
| 2698 | |
| 2699 | * Other callers might not initialize the si_lsb field,
|
| 2700 | * so check explicitly for the right codes here.
|
| 2701 |
|
| 2702 | if (from->si_signo == SIGBUS &&
|
| 2703 | (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO))
|
| 2704 | err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb);
|
| 2705 | #endif
|
| 2706 | #ifdef SEGV_BNDERR
|
| 2707 | if (from->si_signo == SIGSEGV && from->si_code == SEGV_BNDERR) {
|
| 2708 | err |= __put_user(from->si_lower, &to->si_lower);
|
| 2709 | err |= __put_user(from->si_upper, &to->si_upper);
|
| 2710 | }
|
| 2711 | #endif
|
| 2712 | #ifdef SEGV_PKUERR
|
| 2713 | if (from->si_signo == SIGSEGV && from->si_code == SEGV_PKUERR)
|
| 2714 | err |= __put_user(from->si_pkey, &to->si_pkey);
|
| 2715 | #endif
|
| 2716 | break;
|
| 2717 | case __SI_CHLD:
|
| 2718 | err |= __put_user(from->si_pid, &to->si_pid);
|
| 2719 | err |= __put_user(from->si_uid, &to->si_uid);
|
| 2720 | err |= __put_user(from->si_status, &to->si_status);
|
| 2721 | err |= __put_user(from->si_utime, &to->si_utime);
|
| 2722 | err |= __put_user(from->si_stime, &to->si_stime);
|
| 2723 | break;
|
| 2724 | case __SI_RT:
|
| 2725 | case __SI_MESGQ:
|
| 2726 | err |= __put_user(from->si_pid, &to->si_pid);
|
| 2727 | err |= __put_user(from->si_uid, &to->si_uid);
|
| 2728 | err |= __put_user(from->si_ptr, &to->si_ptr);
|
| 2729 | break;
|
| 2730 | #ifdef __ARCH_SIGSYS
|
| 2731 | case __SI_SYS:
|
| 2732 | err |= __put_user(from->si_call_addr, &to->si_call_addr);
|
| 2733 | err |= __put_user(from->si_syscall, &to->si_syscall);
|
| 2734 | err |= __put_user(from->si_arch, &to->si_arch);
|
| 2735 | break;
|
| 2736 | #endif
|
| 2737 | default:
|
| 2738 | err |= __put_user(from->si_pid, &to->si_pid);
|
| 2739 | err |= __put_user(from->si_uid, &to->si_uid);
|
| 2740 | break;
|
| 2741 | }
|
| 2742 | return err;
|
| 2743 | }
|
| 2744 |
|
| 2745 | #endif
|
| 2746 |
|
| 2747 | |
| 2748 | * do_sigtimedwait - wait for queued signals specified in @which
|
| 2749 | * @which: queued signals to wait for
|
| 2750 | * @info: if non-null, the signal's siginfo is returned here
|
| 2751 | * @ts: upper bound on process time suspension
|
| 2752 |
|
| 2753 | int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
|
| 2754 | const struct timespec *ts)
|
| 2755 | {
|
| 2756 | ktime_t *to = NULL, timeout = { .tv64 = KTIME_MAX };
|
| 2757 | struct task_struct *tsk = current;
|
| 2758 | sigset_t mask = *which;
|
| 2759 | int sig, ret = 0;
|
| 2760 |
|
| 2761 | if (ts) {
|
| 2762 | if (!timespec_valid(ts))
|
| 2763 | return -EINVAL;
|
| 2764 | timeout = timespec_to_ktime(*ts);
|
| 2765 | to = &timeout;
|
| 2766 | }
|
| 2767 |
|
| 2768 | |
| 2769 | * Invert the set of allowed signals to get those we want to block.
|
| 2770 |
|
| 2771 | sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
|
| 2772 | signotset(&mask);
|
| 2773 |
|
| 2774 | spin_lock_irq(&tsk->sighand->siglock);
|
| 2775 | sig = dequeue_signal(tsk, &mask, info);
|
| 2776 | if (!sig && timeout.tv64) {
|
| 2777 | |
| 2778 | * None ready, temporarily unblock those we're interested
|
| 2779 | * while we are sleeping in so that we'll be awakened when
|
| 2780 | * they arrive. Unblocking is always fine, we can avoid
|
| 2781 | * set_current_blocked().
|
| 2782 |
|
| 2783 | tsk->real_blocked = tsk->blocked;
|
| 2784 | sigandsets(&tsk->blocked, &tsk->blocked, &mask);
|
| 2785 | recalc_sigpending();
|
| 2786 | spin_unlock_irq(&tsk->sighand->siglock);
|
| 2787 |
|
| 2788 | __set_current_state(TASK_INTERRUPTIBLE);
|
| 2789 | ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns,
|
| 2790 | HRTIMER_MODE_REL);
|
| 2791 | spin_lock_irq(&tsk->sighand->siglock);
|
| 2792 | __set_task_blocked(tsk, &tsk->real_blocked);
|
| 2793 | sigemptyset(&tsk->real_blocked);
|
| 2794 | sig = dequeue_signal(tsk, &mask, info);
|
| 2795 | }
|
| 2796 | spin_unlock_irq(&tsk->sighand->siglock);
|
| 2797 |
|
| 2798 | if (sig)
|
| 2799 | return sig;
|
| 2800 | return ret ? -EINTR : -EAGAIN;
|
| 2801 | }
|
| 2802 |
|
| 2803 | |
| 2804 | * sys_rt_sigtimedwait - synchronously wait for queued signals specified
|
| 2805 | * in @uthese
|
| 2806 | * @uthese: queued signals to wait for
|
| 2807 | * @uinfo: if non-null, the signal's siginfo is returned here
|
| 2808 | * @uts: upper bound on process time suspension
|
| 2809 | * @sigsetsize: size of sigset_t type
|
| 2810 |
|
| 2811 | SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
|
| 2812 | siginfo_t __user *, uinfo, const struct timespec __user *, uts,
|
| 2813 | size_t, sigsetsize)
|
| 2814 | {
|
| 2815 | sigset_t these;
|
| 2816 | struct timespec ts;
|
| 2817 | siginfo_t info;
|
| 2818 | int ret;
|
| 2819 |
|
| 2820 |
|
| 2821 | if (sigsetsize != sizeof(sigset_t))
|
| 2822 | return -EINVAL;
|
| 2823 |
|
| 2824 | if (copy_from_user(&these, uthese, sizeof(these)))
|
| 2825 | return -EFAULT;
|
| 2826 |
|
| 2827 | if (uts) {
|
| 2828 | if (copy_from_user(&ts, uts, sizeof(ts)))
|
| 2829 | return -EFAULT;
|
| 2830 | }
|
| 2831 |
|
| 2832 | ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
|
| 2833 |
|
| 2834 | if (ret > 0 && uinfo) {
|
| 2835 | if (copy_siginfo_to_user(uinfo, &info))
|
| 2836 | ret = -EFAULT;
|
| 2837 | }
|
| 2838 |
|
| 2839 | return ret;
|
| 2840 | }
|
| 2841 |
|
| 2842 | |
| 2843 | * sys_kill - send a signal to a process
|
| 2844 | * @pid: the PID of the process
|
| 2845 | * @sig: signal to be sent
|
| 2846 |
|
| 2847 | SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
|
| 2848 | {
|
| 2849 | struct siginfo info;
|
| 2850 |
|
| 2851 | info.si_signo = sig;
|
| 2852 | info.si_errno = 0;
|
| 2853 | info.si_code = SI_USER;
|
| 2854 | info.si_pid = task_tgid_vnr(current);
|
| 2855 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
|
| 2856 |
|
| 2857 | return kill_something_info(sig, &info, pid);
|
| 2858 | }
|
| 2859 |
|
| 2860 | static int
|
| 2861 | do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info)
|
| 2862 | {
|
| 2863 | struct task_struct *p;
|
| 2864 | int error = -ESRCH;
|
| 2865 |
|
| 2866 | rcu_read_lock();
|
| 2867 | p = find_task_by_vpid(pid);
|
| 2868 | if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
|
| 2869 | error = check_kill_permission(sig, info, p);
|
| 2870 | |
| 2871 | * The null signal is a permissions and process existence
|
| 2872 | * probe. No signal is actually delivered.
|
| 2873 |
|
| 2874 | if (!error && sig) {
|
| 2875 | error = do_send_sig_info(sig, info, p, false);
|
| 2876 | |
| 2877 | * If lock_task_sighand() failed we pretend the task
|
| 2878 | * dies after receiving the signal. The window is tiny,
|
| 2879 | * and the signal is private anyway.
|
| 2880 |
|
| 2881 | if (unlikely(error == -ESRCH))
|
| 2882 | error = 0;
|
| 2883 | }
|
| 2884 | }
|
| 2885 | rcu_read_unlock();
|
| 2886 |
|
| 2887 | return error;
|
| 2888 | }
|
| 2889 |
|
| 2890 | static int do_tkill(pid_t tgid, pid_t pid, int sig)
|
| 2891 | {
|
| 2892 | struct siginfo info = {};
|
| 2893 |
|
| 2894 | info.si_signo = sig;
|
| 2895 | info.si_errno = 0;
|
| 2896 | info.si_code = SI_TKILL;
|
| 2897 | info.si_pid = task_tgid_vnr(current);
|
| 2898 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
|
| 2899 |
|
| 2900 | return do_send_specific(tgid, pid, sig, &info);
|
| 2901 | }
|
| 2902 |
|
| 2903 | |
| 2904 | * sys_tgkill - send signal to one specific thread
|
| 2905 | * @tgid: the thread group ID of the thread
|
| 2906 | * @pid: the PID of the thread
|
| 2907 | * @sig: signal to be sent
|
| 2908 | *
|
| 2909 | * This syscall also checks the @tgid and returns -ESRCH even if the PID
|
| 2910 | * exists but it's not belonging to the target process anymore. This
|
| 2911 | * method solves the problem of threads exiting and PIDs getting reused.
|
| 2912 |
|
| 2913 | SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
|
| 2914 | {
|
| 2915 |
|
| 2916 | if (pid <= 0 || tgid <= 0)
|
| 2917 | return -EINVAL;
|
| 2918 |
|
| 2919 | return do_tkill(tgid, pid, sig);
|
| 2920 | }
|
| 2921 |
|
| 2922 | |
| 2923 | * sys_tkill - send signal to one specific task
|
| 2924 | * @pid: the PID of the task
|
| 2925 | * @sig: signal to be sent
|
| 2926 | *
|
| 2927 | * Send a signal to only one task, even if it's a CLONE_THREAD task.
|
| 2928 |
|
| 2929 | SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
|
| 2930 | {
|
| 2931 |
|
| 2932 | if (pid <= 0)
|
| 2933 | return -EINVAL;
|
| 2934 |
|
| 2935 | return do_tkill(0, pid, sig);
|
| 2936 | }
|
| 2937 |
|
| 2938 | static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info)
|
| 2939 | {
|
| 2940 | |
| 2941 | * Nor can they impersonate a kill()/tgkill(), which adds source info.
|
| 2942 |
|
| 2943 | if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
|
| 2944 | (task_pid_vnr(current) != pid))
|
| 2945 | return -EPERM;
|
| 2946 |
|
| 2947 | info->si_signo = sig;
|
| 2948 |
|
| 2949 |
|
| 2950 | return kill_proc_info(sig, info, pid);
|
| 2951 | }
|
| 2952 |
|
| 2953 | |
| 2954 | * sys_rt_sigqueueinfo - send signal information to a signal
|
| 2955 | * @pid: the PID of the thread
|
| 2956 | * @sig: signal to be sent
|
| 2957 | * @uinfo: signal info to be sent
|
| 2958 |
|
| 2959 | SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
|
| 2960 | siginfo_t __user *, uinfo)
|
| 2961 | {
|
| 2962 | siginfo_t info;
|
| 2963 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
|
| 2964 | return -EFAULT;
|
| 2965 | return do_rt_sigqueueinfo(pid, sig, &info);
|
| 2966 | }
|
| 2967 |
|
| 2968 | #ifdef CONFIG_COMPAT
|
| 2969 | COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
|
| 2970 | compat_pid_t, pid,
|
| 2971 | int, sig,
|
| 2972 | struct compat_siginfo __user *, uinfo)
|
| 2973 | {
|
| 2974 | siginfo_t info = {};
|
| 2975 | int ret = copy_siginfo_from_user32(&info, uinfo);
|
| 2976 | if (unlikely(ret))
|
| 2977 | return ret;
|
| 2978 | return do_rt_sigqueueinfo(pid, sig, &info);
|
| 2979 | }
|
| 2980 | #endif
|
| 2981 |
|
| 2982 | static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
|
| 2983 | {
|
| 2984 |
|
| 2985 | if (pid <= 0 || tgid <= 0)
|
| 2986 | return -EINVAL;
|
| 2987 |
|
| 2988 | |
| 2989 | * Nor can they impersonate a kill()/tgkill(), which adds source info.
|
| 2990 |
|
| 2991 | if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
|
| 2992 | (task_pid_vnr(current) != pid))
|
| 2993 | return -EPERM;
|
| 2994 |
|
| 2995 | info->si_signo = sig;
|
| 2996 |
|
| 2997 | return do_send_specific(tgid, pid, sig, info);
|
| 2998 | }
|
| 2999 |
|
| 3000 | SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
|
| 3001 | siginfo_t __user *, uinfo)
|
| 3002 | {
|
| 3003 | siginfo_t info;
|
| 3004 |
|
| 3005 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
|
| 3006 | return -EFAULT;
|
| 3007 |
|
| 3008 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
|
| 3009 | }
|
| 3010 |
|
| 3011 | #ifdef CONFIG_COMPAT
|
| 3012 | COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
|
| 3013 | compat_pid_t, tgid,
|
| 3014 | compat_pid_t, pid,
|
| 3015 | int, sig,
|
| 3016 | struct compat_siginfo __user *, uinfo)
|
| 3017 | {
|
| 3018 | siginfo_t info = {};
|
| 3019 |
|
| 3020 | if (copy_siginfo_from_user32(&info, uinfo))
|
| 3021 | return -EFAULT;
|
| 3022 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
|
| 3023 | }
|
| 3024 | #endif
|
| 3025 |
|
| 3026 | |
| 3027 | * For kthreads only, must not be used if cloned with CLONE_SIGHAND
|
| 3028 |
|
| 3029 | void kernel_sigaction(int sig, __sighandler_t action)
|
| 3030 | {
|
| 3031 | spin_lock_irq(¤t->sighand->siglock);
|
| 3032 | current->sighand->action[sig - 1].sa.sa_handler = action;
|
| 3033 | if (action == SIG_IGN) {
|
| 3034 | sigset_t mask;
|
| 3035 |
|
| 3036 | sigemptyset(&mask);
|
| 3037 | sigaddset(&mask, sig);
|
| 3038 |
|
| 3039 | flush_sigqueue_mask(&mask, ¤t->signal->shared_pending);
|
| 3040 | flush_sigqueue_mask(&mask, ¤t->pending);
|
| 3041 | recalc_sigpending();
|
| 3042 | }
|
| 3043 | spin_unlock_irq(¤t->sighand->siglock);
|
| 3044 | }
|
| 3045 | EXPORT_SYMBOL(kernel_sigaction);
|
| 3046 |
|
| 3047 | int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
|
| 3048 | {
|
| 3049 | struct task_struct *p = current, *t;
|
| 3050 | struct k_sigaction *k;
|
| 3051 | sigset_t mask;
|
| 3052 |
|
| 3053 | if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
|
| 3054 | return -EINVAL;
|
| 3055 |
|
| 3056 | k = &p->sighand->action[sig-1];
|
| 3057 |
|
| 3058 | spin_lock_irq(&p->sighand->siglock);
|
| 3059 | if (oact)
|
| 3060 | *oact = *k;
|
| 3061 |
|
| 3062 | if (act) {
|
| 3063 | sigdelsetmask(&act->sa.sa_mask,
|
| 3064 | sigmask(SIGKILL) | sigmask(SIGSTOP));
|
| 3065 | *k = *act;
|
| 3066 | |
| 3067 | * POSIX 3.3.1.3:
|
| 3068 | * "Setting a signal action to SIG_IGN for a signal that is
|
| 3069 | * pending shall cause the pending signal to be discarded,
|
| 3070 | * whether or not it is blocked."
|
| 3071 | *
|
| 3072 | * "Setting a signal action to SIG_DFL for a signal that is
|
| 3073 | * pending and whose default action is to ignore the signal
|
| 3074 | * (for example, SIGCHLD), shall cause the pending signal to
|
| 3075 | * be discarded, whether or not it is blocked"
|
| 3076 |
|
| 3077 | if (sig_handler_ignored(sig_handler(p, sig), sig)) {
|
| 3078 | sigemptyset(&mask);
|
| 3079 | sigaddset(&mask, sig);
|
| 3080 | flush_sigqueue_mask(&mask, &p->signal->shared_pending);
|
| 3081 | for_each_thread(p, t)
|
| 3082 | flush_sigqueue_mask(&mask, &t->pending);
|
| 3083 | }
|
| 3084 | }
|
| 3085 |
|
| 3086 | spin_unlock_irq(&p->sighand->siglock);
|
| 3087 | return 0;
|
| 3088 | }
|
| 3089 |
|
| 3090 | static int
|
| 3091 | do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp)
|
| 3092 | {
|
| 3093 | stack_t oss;
|
| 3094 | int error;
|
| 3095 |
|
| 3096 | oss.ss_sp = (void __user *) current->sas_ss_sp;
|
| 3097 | oss.ss_size = current->sas_ss_size;
|
| 3098 | oss.ss_flags = sas_ss_flags(sp) |
|
| 3099 | (current->sas_ss_flags & SS_FLAG_BITS);
|
| 3100 |
|
| 3101 | if (uss) {
|
| 3102 | void __user *ss_sp;
|
| 3103 | size_t ss_size;
|
| 3104 | unsigned ss_flags;
|
| 3105 | int ss_mode;
|
| 3106 |
|
| 3107 | error = -EFAULT;
|
| 3108 | if (!access_ok(VERIFY_READ, uss, sizeof(*uss)))
|
| 3109 | goto out;
|
| 3110 | error = __get_user(ss_sp, &uss->ss_sp) |
|
| 3111 | __get_user(ss_flags, &uss->ss_flags) |
|
| 3112 | __get_user(ss_size, &uss->ss_size);
|
| 3113 | if (error)
|
| 3114 | goto out;
|
| 3115 |
|
| 3116 | error = -EPERM;
|
| 3117 | if (on_sig_stack(sp))
|
| 3118 | goto out;
|
| 3119 |
|
| 3120 | ss_mode = ss_flags & ~SS_FLAG_BITS;
|
| 3121 | error = -EINVAL;
|
| 3122 | if (ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK &&
|
| 3123 | ss_mode != 0)
|
| 3124 | goto out;
|
| 3125 |
|
| 3126 | if (ss_mode == SS_DISABLE) {
|
| 3127 | ss_size = 0;
|
| 3128 | ss_sp = NULL;
|
| 3129 | } else {
|
| 3130 | error = -ENOMEM;
|
| 3131 | if (ss_size < MINSIGSTKSZ)
|
| 3132 | goto out;
|
| 3133 | }
|
| 3134 |
|
| 3135 | current->sas_ss_sp = (unsigned long) ss_sp;
|
| 3136 | current->sas_ss_size = ss_size;
|
| 3137 | current->sas_ss_flags = ss_flags;
|
| 3138 | }
|
| 3139 |
|
| 3140 | error = 0;
|
| 3141 | if (uoss) {
|
| 3142 | error = -EFAULT;
|
| 3143 | if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss)))
|
| 3144 | goto out;
|
| 3145 | error = __put_user(oss.ss_sp, &uoss->ss_sp) |
|
| 3146 | __put_user(oss.ss_size, &uoss->ss_size) |
|
| 3147 | __put_user(oss.ss_flags, &uoss->ss_flags);
|
| 3148 | }
|
| 3149 |
|
| 3150 | out:
|
| 3151 | return error;
|
| 3152 | }
|
| 3153 | SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
|
| 3154 | {
|
| 3155 | return do_sigaltstack(uss, uoss, current_user_stack_pointer());
|
| 3156 | }
|
| 3157 |
|
| 3158 | int restore_altstack(const stack_t __user *uss)
|
| 3159 | {
|
| 3160 | int err = do_sigaltstack(uss, NULL, current_user_stack_pointer());
|
| 3161 |
|
| 3162 | return err == -EFAULT ? err : 0;
|
| 3163 | }
|
| 3164 |
|
| 3165 | int __save_altstack(stack_t __user *uss, unsigned long sp)
|
| 3166 | {
|
| 3167 | struct task_struct *t = current;
|
| 3168 | int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
|
| 3169 | __put_user(t->sas_ss_flags, &uss->ss_flags) |
|
| 3170 | __put_user(t->sas_ss_size, &uss->ss_size);
|
| 3171 | if (err)
|
| 3172 | return err;
|
| 3173 | if (t->sas_ss_flags & SS_AUTODISARM)
|
| 3174 | sas_ss_reset(t);
|
| 3175 | return 0;
|
| 3176 | }
|
| 3177 |
|
| 3178 | #ifdef CONFIG_COMPAT
|
| 3179 | COMPAT_SYSCALL_DEFINE2(sigaltstack,
|
| 3180 | const compat_stack_t __user *, uss_ptr,
|
| 3181 | compat_stack_t __user *, uoss_ptr)
|
| 3182 | {
|
| 3183 | stack_t uss, uoss;
|
| 3184 | int ret;
|
| 3185 | mm_segment_t seg;
|
| 3186 |
|
| 3187 | if (uss_ptr) {
|
| 3188 | compat_stack_t uss32;
|
| 3189 |
|
| 3190 | memset(&uss, 0, sizeof(stack_t));
|
| 3191 | if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
|
| 3192 | return -EFAULT;
|
| 3193 | uss.ss_sp = compat_ptr(uss32.ss_sp);
|
| 3194 | uss.ss_flags = uss32.ss_flags;
|
| 3195 | uss.ss_size = uss32.ss_size;
|
| 3196 | }
|
| 3197 | seg = get_fs();
|
| 3198 | set_fs(KERNEL_DS);
|
| 3199 | ret = do_sigaltstack((stack_t __force __user *) (uss_ptr ? &uss : NULL),
|
| 3200 | (stack_t __force __user *) &uoss,
|
| 3201 | compat_user_stack_pointer());
|
| 3202 | set_fs(seg);
|
| 3203 | if (ret >= 0 && uoss_ptr) {
|
| 3204 | if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(compat_stack_t)) ||
|
| 3205 | __put_user(ptr_to_compat(uoss.ss_sp), &uoss_ptr->ss_sp) ||
|
| 3206 | __put_user(uoss.ss_flags, &uoss_ptr->ss_flags) ||
|
| 3207 | __put_user(uoss.ss_size, &uoss_ptr->ss_size))
|
| 3208 | ret = -EFAULT;
|
| 3209 | }
|
| 3210 | return ret;
|
| 3211 | }
|
| 3212 |
|
| 3213 | int compat_restore_altstack(const compat_stack_t __user *uss)
|
| 3214 | {
|
| 3215 | int err = compat_sys_sigaltstack(uss, NULL);
|
| 3216 |
|
| 3217 | return err == -EFAULT ? err : 0;
|
| 3218 | }
|
| 3219 |
|
| 3220 | int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
|
| 3221 | {
|
| 3222 | struct task_struct *t = current;
|
| 3223 | return __put_user(ptr_to_compat((void __user *)t->sas_ss_sp), &uss->ss_sp) |
|
| 3224 | __put_user(sas_ss_flags(sp), &uss->ss_flags) |
|
| 3225 | __put_user(t->sas_ss_size, &uss->ss_size);
|
| 3226 | }
|
| 3227 | #endif
|
| 3228 |
|
| 3229 | #ifdef __ARCH_WANT_SYS_SIGPENDING
|
| 3230 |
|
| 3231 | |
| 3232 | * sys_sigpending - examine pending signals
|
| 3233 | * @set: where mask of pending signal is returned
|
| 3234 |
|
| 3235 | SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set)
|
| 3236 | {
|
| 3237 | return sys_rt_sigpending((sigset_t __user *)set, sizeof(old_sigset_t));
|
| 3238 | }
|
| 3239 |
|
| 3240 | #endif
|
| 3241 |
|
| 3242 | #ifdef __ARCH_WANT_SYS_SIGPROCMASK
|
| 3243 | |
| 3244 | * sys_sigprocmask - examine and change blocked signals
|
| 3245 | * @how: whether to add, remove, or set signals
|
| 3246 | * @nset: signals to add or remove (if non-null)
|
| 3247 | * @oset: previous value of signal mask if non-null
|
| 3248 | *
|
| 3249 | * Some platforms have their own version with special arguments;
|
| 3250 | * others support only sys_rt_sigprocmask.
|
| 3251 |
|
| 3252 |
|
| 3253 | SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
|
| 3254 | old_sigset_t __user *, oset)
|
| 3255 | {
|
| 3256 | old_sigset_t old_set, new_set;
|
| 3257 | sigset_t new_blocked;
|
| 3258 |
|
| 3259 | old_set = current->blocked.sig[0];
|
| 3260 |
|
| 3261 | if (nset) {
|
| 3262 | if (copy_from_user(&new_set, nset, sizeof(*nset)))
|
| 3263 | return -EFAULT;
|
| 3264 |
|
| 3265 | new_blocked = current->blocked;
|
| 3266 |
|
| 3267 | switch (how) {
|
| 3268 | case SIG_BLOCK:
|
| 3269 | sigaddsetmask(&new_blocked, new_set);
|
| 3270 | break;
|
| 3271 | case SIG_UNBLOCK:
|
| 3272 | sigdelsetmask(&new_blocked, new_set);
|
| 3273 | break;
|
| 3274 | case SIG_SETMASK:
|
| 3275 | new_blocked.sig[0] = new_set;
|
| 3276 | break;
|
| 3277 | default:
|
| 3278 | return -EINVAL;
|
| 3279 | }
|
| 3280 |
|
| 3281 | set_current_blocked(&new_blocked);
|
| 3282 | }
|
| 3283 |
|
| 3284 | if (oset) {
|
| 3285 | if (copy_to_user(oset, &old_set, sizeof(*oset)))
|
| 3286 | return -EFAULT;
|
| 3287 | }
|
| 3288 |
|
| 3289 | return 0;
|
| 3290 | }
|
| 3291 | #endif
|
| 3292 |
|
| 3293 | #ifndef CONFIG_ODD_RT_SIGACTION
|
| 3294 | |
| 3295 | * sys_rt_sigaction - alter an action taken by a process
|
| 3296 | * @sig: signal to be sent
|
| 3297 | * @act: new sigaction
|
| 3298 | * @oact: used to save the previous sigaction
|
| 3299 | * @sigsetsize: size of sigset_t type
|
| 3300 |
|
| 3301 | SYSCALL_DEFINE4(rt_sigaction, int, sig,
|
| 3302 | const struct sigaction __user *, act,
|
| 3303 | struct sigaction __user *, oact,
|
| 3304 | size_t, sigsetsize)
|
| 3305 | {
|
| 3306 | struct k_sigaction new_sa, old_sa;
|
| 3307 | int ret = -EINVAL;
|
| 3308 |
|
| 3309 |
|
| 3310 | if (sigsetsize != sizeof(sigset_t))
|
| 3311 | goto out;
|
| 3312 |
|
| 3313 | if (act) {
|
| 3314 | if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
|
| 3315 | return -EFAULT;
|
| 3316 | }
|
| 3317 |
|
| 3318 | ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
|
| 3319 |
|
| 3320 | if (!ret && oact) {
|
| 3321 | if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
|
| 3322 | return -EFAULT;
|
| 3323 | }
|
| 3324 | out:
|
| 3325 | return ret;
|
| 3326 | }
|
| 3327 | #ifdef CONFIG_COMPAT
|
| 3328 | COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
|
| 3329 | const struct compat_sigaction __user *, act,
|
| 3330 | struct compat_sigaction __user *, oact,
|
| 3331 | compat_size_t, sigsetsize)
|
| 3332 | {
|
| 3333 | struct k_sigaction new_ka, old_ka;
|
| 3334 | compat_sigset_t mask;
|
| 3335 | #ifdef __ARCH_HAS_SA_RESTORER
|
| 3336 | compat_uptr_t restorer;
|
| 3337 | #endif
|
| 3338 | int ret;
|
| 3339 |
|
| 3340 |
|
| 3341 | if (sigsetsize != sizeof(compat_sigset_t))
|
| 3342 | return -EINVAL;
|
| 3343 |
|
| 3344 | if (act) {
|
| 3345 | compat_uptr_t handler;
|
| 3346 | ret = get_user(handler, &act->sa_handler);
|
| 3347 | new_ka.sa.sa_handler = compat_ptr(handler);
|
| 3348 | #ifdef __ARCH_HAS_SA_RESTORER
|
| 3349 | ret |= get_user(restorer, &act->sa_restorer);
|
| 3350 | new_ka.sa.sa_restorer = compat_ptr(restorer);
|
| 3351 | #endif
|
| 3352 | ret |= copy_from_user(&mask, &act->sa_mask, sizeof(mask));
|
| 3353 | ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
|
| 3354 | if (ret)
|
| 3355 | return -EFAULT;
|
| 3356 | sigset_from_compat(&new_ka.sa.sa_mask, &mask);
|
| 3357 | }
|
| 3358 |
|
| 3359 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
|
| 3360 | if (!ret && oact) {
|
| 3361 | sigset_to_compat(&mask, &old_ka.sa.sa_mask);
|
| 3362 | ret = put_user(ptr_to_compat(old_ka.sa.sa_handler),
|
| 3363 | &oact->sa_handler);
|
| 3364 | ret |= copy_to_user(&oact->sa_mask, &mask, sizeof(mask));
|
| 3365 | ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
|
| 3366 | #ifdef __ARCH_HAS_SA_RESTORER
|
| 3367 | ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
|
| 3368 | &oact->sa_restorer);
|
| 3369 | #endif
|
| 3370 | }
|
| 3371 | return ret;
|
| 3372 | }
|
| 3373 | #endif
|
| 3374 | #endif
|
| 3375 |
|
| 3376 | #ifdef CONFIG_OLD_SIGACTION
|
| 3377 | SYSCALL_DEFINE3(sigaction, int, sig,
|
| 3378 | const struct old_sigaction __user *, act,
|
| 3379 | struct old_sigaction __user *, oact)
|
| 3380 | {
|
| 3381 | struct k_sigaction new_ka, old_ka;
|
| 3382 | int ret;
|
| 3383 |
|
| 3384 | if (act) {
|
| 3385 | old_sigset_t mask;
|
| 3386 | if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
|
| 3387 | __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
|
| 3388 | __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
|
| 3389 | __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
|
| 3390 | __get_user(mask, &act->sa_mask))
|
| 3391 | return -EFAULT;
|
| 3392 | #ifdef __ARCH_HAS_KA_RESTORER
|
| 3393 | new_ka.ka_restorer = NULL;
|
| 3394 | #endif
|
| 3395 | siginitset(&new_ka.sa.sa_mask, mask);
|
| 3396 | }
|
| 3397 |
|
| 3398 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
|
| 3399 |
|
| 3400 | if (!ret && oact) {
|
| 3401 | if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
|
| 3402 | __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
|
| 3403 | __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
|
| 3404 | __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
|
| 3405 | __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
|
| 3406 | return -EFAULT;
|
| 3407 | }
|
| 3408 |
|
| 3409 | return ret;
|
| 3410 | }
|
| 3411 | #endif
|
| 3412 | #ifdef CONFIG_COMPAT_OLD_SIGACTION
|
| 3413 | COMPAT_SYSCALL_DEFINE3(sigaction, int, sig,
|
| 3414 | const struct compat_old_sigaction __user *, act,
|
| 3415 | struct compat_old_sigaction __user *, oact)
|
| 3416 | {
|
| 3417 | struct k_sigaction new_ka, old_ka;
|
| 3418 | int ret;
|
| 3419 | compat_old_sigset_t mask;
|
| 3420 | compat_uptr_t handler, restorer;
|
| 3421 |
|
| 3422 | if (act) {
|
| 3423 | if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
|
| 3424 | __get_user(handler, &act->sa_handler) ||
|
| 3425 | __get_user(restorer, &act->sa_restorer) ||
|
| 3426 | __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
|
| 3427 | __get_user(mask, &act->sa_mask))
|
| 3428 | return -EFAULT;
|
| 3429 |
|
| 3430 | #ifdef __ARCH_HAS_KA_RESTORER
|
| 3431 | new_ka.ka_restorer = NULL;
|
| 3432 | #endif
|
| 3433 | new_ka.sa.sa_handler = compat_ptr(handler);
|
| 3434 | new_ka.sa.sa_restorer = compat_ptr(restorer);
|
| 3435 | siginitset(&new_ka.sa.sa_mask, mask);
|
| 3436 | }
|
| 3437 |
|
| 3438 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
|
| 3439 |
|
| 3440 | if (!ret && oact) {
|
| 3441 | if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
|
| 3442 | __put_user(ptr_to_compat(old_ka.sa.sa_handler),
|
| 3443 | &oact->sa_handler) ||
|
| 3444 | __put_user(ptr_to_compat(old_ka.sa.sa_restorer),
|
| 3445 | &oact->sa_restorer) ||
|
| 3446 | __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
|
| 3447 | __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
|
| 3448 | return -EFAULT;
|
| 3449 | }
|
| 3450 | return ret;
|
| 3451 | }
|
| 3452 | #endif
|
| 3453 |
|
| 3454 | #ifdef CONFIG_SGETMASK_SYSCALL
|
| 3455 |
|
| 3456 | |
| 3457 | * For backwards compatibility. Functionality superseded by sigprocmask.
|
| 3458 |
|
| 3459 | SYSCALL_DEFINE0(sgetmask)
|
| 3460 | {
|
| 3461 |
|
| 3462 | return current->blocked.sig[0];
|
| 3463 | }
|
| 3464 |
|
| 3465 | SYSCALL_DEFINE1(ssetmask, int, newmask)
|
| 3466 | {
|
| 3467 | int old = current->blocked.sig[0];
|
| 3468 | sigset_t newset;
|
| 3469 |
|
| 3470 | siginitset(&newset, newmask);
|
| 3471 | set_current_blocked(&newset);
|
| 3472 |
|
| 3473 | return old;
|
| 3474 | }
|
| 3475 | #endif
|
| 3476 |
|
| 3477 | #ifdef __ARCH_WANT_SYS_SIGNAL
|
| 3478 | |
| 3479 | * For backwards compatibility. Functionality superseded by sigaction.
|
| 3480 |
|
| 3481 | SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
|
| 3482 | {
|
| 3483 | struct k_sigaction new_sa, old_sa;
|
| 3484 | int ret;
|
| 3485 |
|
| 3486 | new_sa.sa.sa_handler = handler;
|
| 3487 | new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
|
| 3488 | sigemptyset(&new_sa.sa.sa_mask);
|
| 3489 |
|
| 3490 | ret = do_sigaction(sig, &new_sa, &old_sa);
|
| 3491 |
|
| 3492 | return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
|
| 3493 | }
|
| 3494 | #endif
|
| 3495 |
|
| 3496 | #ifdef __ARCH_WANT_SYS_PAUSE
|
| 3497 |
|
| 3498 | SYSCALL_DEFINE0(pause)
|
| 3499 | {
|
| 3500 | while (!signal_pending(current)) {
|
| 3501 | __set_current_state(TASK_INTERRUPTIBLE);
|
| 3502 | schedule();
|
| 3503 | }
|
| 3504 | return -ERESTARTNOHAND;
|
| 3505 | }
|
| 3506 |
|
| 3507 | #endif
|
| 3508 |
|
| 3509 | static int sigsuspend(sigset_t *set)
|
| 3510 | {
|
| 3511 | current->saved_sigmask = current->blocked;
|
| 3512 | set_current_blocked(set);
|
| 3513 |
|
| 3514 | while (!signal_pending(current)) {
|
| 3515 | __set_current_state(TASK_INTERRUPTIBLE);
|
| 3516 | schedule();
|
| 3517 | }
|
| 3518 | set_restore_sigmask();
|
| 3519 | return -ERESTARTNOHAND;
|
| 3520 | }
|
| 3521 |
|
| 3522 | |
| 3523 | * sys_rt_sigsuspend - replace the signal mask for a value with the
|
| 3524 | * @unewset value until a signal is received
|
| 3525 | * @unewset: new signal mask value
|
| 3526 | * @sigsetsize: size of sigset_t type
|
| 3527 |
|
| 3528 | SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
|
| 3529 | {
|
| 3530 | sigset_t newset;
|
| 3531 |
|
| 3532 |
|
| 3533 | if (sigsetsize != sizeof(sigset_t))
|
| 3534 | return -EINVAL;
|
| 3535 |
|
| 3536 | if (copy_from_user(&newset, unewset, sizeof(newset)))
|
| 3537 | return -EFAULT;
|
| 3538 | return sigsuspend(&newset);
|
| 3539 | }
|
| 3540 |
|
| 3541 | #ifdef CONFIG_COMPAT
|
| 3542 | COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize)
|
| 3543 | {
|
| 3544 | #ifdef __BIG_ENDIAN
|
| 3545 | sigset_t newset;
|
| 3546 | compat_sigset_t newset32;
|
| 3547 |
|
| 3548 |
|
| 3549 | if (sigsetsize != sizeof(sigset_t))
|
| 3550 | return -EINVAL;
|
| 3551 |
|
| 3552 | if (copy_from_user(&newset32, unewset, sizeof(compat_sigset_t)))
|
| 3553 | return -EFAULT;
|
| 3554 | sigset_from_compat(&newset, &newset32);
|
| 3555 | return sigsuspend(&newset);
|
| 3556 | #else
|
| 3557 |
|
| 3558 | return sys_rt_sigsuspend((sigset_t __user *)unewset, sigsetsize);
|
| 3559 | #endif
|
| 3560 | }
|
| 3561 | #endif
|
| 3562 |
|
| 3563 | #ifdef CONFIG_OLD_SIGSUSPEND
|
| 3564 | SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
|
| 3565 | {
|
| 3566 | sigset_t blocked;
|
| 3567 | siginitset(&blocked, mask);
|
| 3568 | return sigsuspend(&blocked);
|
| 3569 | }
|
| 3570 | #endif
|
| 3571 | #ifdef CONFIG_OLD_SIGSUSPEND3
|
| 3572 | SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask)
|
| 3573 | {
|
| 3574 | sigset_t blocked;
|
| 3575 | siginitset(&blocked, mask);
|
| 3576 | return sigsuspend(&blocked);
|
| 3577 | }
|
| 3578 | #endif
|
| 3579 |
|
| 3580 | __weak const char *arch_vma_name(struct vm_area_struct *vma)
|
| 3581 | {
|
| 3582 | return NULL;
|
| 3583 | }
|
| 3584 |
|
| 3585 | void __init signals_init(void)
|
| 3586 | {
|
| 3587 |
|
| 3588 | BUILD_BUG_ON(__ARCH_SI_PREAMBLE_SIZE
|
| 3589 | != offsetof(struct siginfo, _sifields._pad));
|
| 3590 |
|
| 3591 | sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
|
| 3592 | }
|
| 3593 |
|
| 3594 | #ifdef CONFIG_KGDB_KDB
|
| 3595 | #include <linux/kdb.h>
|
| 3596 | |
| 3597 | * kdb_send_sig_info - Allows kdb to send signals without exposing
|
| 3598 | * signal internals. This function checks if the required locks are
|
| 3599 | * available before calling the main signal code, to avoid kdb
|
| 3600 | * deadlocks.
|
| 3601 |
|
| 3602 | void
|
| 3603 | kdb_send_sig_info(struct task_struct *t, struct siginfo *info)
|
| 3604 | {
|
| 3605 | static struct task_struct *kdb_prev_t;
|
| 3606 | int sig, new_t;
|
| 3607 | if (!spin_trylock(&t->sighand->siglock)) {
|
| 3608 | kdb_printf("Can't do kill command now.\n"
|
| 3609 | "The sigmask lock is held somewhere else in "
|
| 3610 | "kernel, try again later\n");
|
| 3611 | return;
|
| 3612 | }
|
| 3613 | spin_unlock(&t->sighand->siglock);
|
| 3614 | new_t = kdb_prev_t != t;
|
| 3615 | kdb_prev_t = t;
|
| 3616 | if (t->state != TASK_RUNNING && new_t) {
|
| 3617 | kdb_printf("Process is not RUNNING, sending a signal from "
|
| 3618 | "kdb risks deadlock\n"
|
| 3619 | "on the run queue locks. "
|
| 3620 | "The signal has _not_ been sent.\n"
|
| 3621 | "Reissue the kill command if you want to risk "
|
| 3622 | "the deadlock.\n");
|
| 3623 | return;
|
| 3624 | }
|
| 3625 | sig = info->si_signo;
|
| 3626 | if (send_sig_info(sig, info, t))
|
| 3627 | kdb_printf("Fail to deliver Signal %d to process %d.\n",
|
| 3628 | sig, t->pid);
|
| 3629 | else
|
| 3630 | kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
|
| 3631 | }
|
| 3632 | #endif
|