diff options
Diffstat (limited to 'kernel/signal.c')
| -rw-r--r-- | kernel/signal.c | 217 |
1 files changed, 209 insertions, 8 deletions
diff --git a/kernel/signal.c b/kernel/signal.c index 9a32bc2088c9..57b7771e20d7 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -688,6 +688,48 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, kernel_siginfo_t *in } EXPORT_SYMBOL_GPL(dequeue_signal); +static int dequeue_synchronous_signal(kernel_siginfo_t *info) +{ + struct task_struct *tsk = current; + struct sigpending *pending = &tsk->pending; + struct sigqueue *q, *sync = NULL; + + /* + * Might a synchronous signal be in the queue? + */ + if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK)) + return 0; + + /* + * Return the first synchronous signal in the queue. + */ + list_for_each_entry(q, &pending->list, list) { + /* Synchronous signals have a postive si_code */ + if ((q->info.si_code > SI_USER) && + (sigmask(q->info.si_signo) & SYNCHRONOUS_MASK)) { + sync = q; + goto next; + } + } + return 0; +next: + /* + * Check if there is another siginfo for the same signal. + */ + list_for_each_entry_continue(q, &pending->list, list) { + if (q->info.si_signo == sync->info.si_signo) + goto still_pending; + } + + sigdelset(&pending->signal, sync->info.si_signo); + recalc_sigpending(); +still_pending: + list_del_init(&sync->list); + copy_siginfo(info, &sync->info); + __sigqueue_free(sync); + return info->si_signo; +} + /* * Tell a process that it has a new active signal.. * @@ -1057,10 +1099,9 @@ static int __send_signal(int sig, struct kernel_siginfo *info, struct task_struc result = TRACE_SIGNAL_DELIVERED; /* - * Skip useless siginfo allocation for SIGKILL SIGSTOP, - * and kernel threads. + * Skip useless siginfo allocation for SIGKILL and kernel threads. */ - if (sig_kernel_only(sig) || (t->flags & PF_KTHREAD)) + if ((sig == SIGKILL) || (t->flags & PF_KTHREAD)) goto out_set; /* @@ -2394,6 +2435,14 @@ relock: goto relock; } + /* Has this task already been marked for death? */ + if (signal_group_exit(signal)) { + ksig->info.si_signo = signr = SIGKILL; + sigdelset(¤t->pending.signal, SIGKILL); + recalc_sigpending(); + goto fatal; + } + for (;;) { struct k_sigaction *ka; @@ -2407,7 +2456,15 @@ relock: goto relock; } - signr = dequeue_signal(current, ¤t->blocked, &ksig->info); + /* + * Signals generated by the execution of an instruction + * need to be delivered before any other pending signals + * so that the instruction pointer in the signal stack + * frame points to the faulting instruction. + */ + signr = dequeue_synchronous_signal(&ksig->info); + if (!signr) + signr = dequeue_signal(current, ¤t->blocked, &ksig->info); if (!signr) break; /* will return 0 */ @@ -2489,6 +2546,7 @@ relock: continue; } + fatal: spin_unlock_irq(&sighand->siglock); /* @@ -2735,6 +2793,84 @@ int sigprocmask(int how, sigset_t *set, sigset_t *oldset) } EXPORT_SYMBOL(sigprocmask); +/* + * The api helps set app-provided sigmasks. + * + * This is useful for syscalls such as ppoll, pselect, io_pgetevents and + * epoll_pwait where a new sigmask is passed from userland for the syscalls. + */ +int set_user_sigmask(const sigset_t __user *usigmask, sigset_t *set, + sigset_t *oldset, size_t sigsetsize) +{ + if (!usigmask) + return 0; + + if (sigsetsize != sizeof(sigset_t)) + return -EINVAL; + if (copy_from_user(set, usigmask, sizeof(sigset_t))) + return -EFAULT; + + *oldset = current->blocked; + set_current_blocked(set); + + return 0; +} +EXPORT_SYMBOL(set_user_sigmask); + +#ifdef CONFIG_COMPAT +int set_compat_user_sigmask(const compat_sigset_t __user *usigmask, + sigset_t *set, sigset_t *oldset, + size_t sigsetsize) +{ + if (!usigmask) + return 0; + + if (sigsetsize != sizeof(compat_sigset_t)) + return -EINVAL; + if (get_compat_sigset(set, usigmask)) + return -EFAULT; + + *oldset = current->blocked; + set_current_blocked(set); + + return 0; +} +EXPORT_SYMBOL(set_compat_user_sigmask); +#endif + +/* + * restore_user_sigmask: + * usigmask: sigmask passed in from userland. + * sigsaved: saved sigmask when the syscall started and changed the sigmask to + * usigmask. + * + * This is useful for syscalls such as ppoll, pselect, io_pgetevents and + * epoll_pwait where a new sigmask is passed in from userland for the syscalls. + */ +void restore_user_sigmask(const void __user *usigmask, sigset_t *sigsaved) +{ + + if (!usigmask) + return; + /* + * When signals are pending, do not restore them here. + * Restoring sigmask here can lead to delivering signals that the above + * syscalls are intended to block because of the sigmask passed in. + */ + if (signal_pending(current)) { + current->saved_sigmask = *sigsaved; + set_restore_sigmask(); + return; + } + + /* + * This is needed because the fast syscall return path does not restore + * saved_sigmask when signals are not pending. + */ + set_current_blocked(sigsaved); +} +EXPORT_SYMBOL(restore_user_sigmask); + /** * sys_rt_sigprocmask - change the list of currently blocked signals * @how: whether to add, remove, or set signals @@ -3254,7 +3390,71 @@ SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese, return ret; } +#ifdef CONFIG_COMPAT_32BIT_TIME +SYSCALL_DEFINE4(rt_sigtimedwait_time32, const sigset_t __user *, uthese, + siginfo_t __user *, uinfo, + const struct old_timespec32 __user *, uts, + size_t, sigsetsize) +{ + sigset_t these; + struct timespec64 ts; + kernel_siginfo_t info; + int ret; + + if (sigsetsize != sizeof(sigset_t)) + return -EINVAL; + + if (copy_from_user(&these, uthese, sizeof(these))) + return -EFAULT; + + if (uts) { + if (get_old_timespec32(&ts, uts)) + return -EFAULT; + } + + ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL); + + if (ret > 0 && uinfo) { + if (copy_siginfo_to_user(uinfo, &info)) + ret = -EFAULT; + } + + return ret; +} +#endif + #ifdef CONFIG_COMPAT +COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time64, compat_sigset_t __user *, uthese, + struct compat_siginfo __user *, uinfo, + struct __kernel_timespec __user *, uts, compat_size_t, sigsetsize) +{ + sigset_t s; + struct timespec64 t; + kernel_siginfo_t info; + long ret; + + if (sigsetsize != sizeof(sigset_t)) + return -EINVAL; + + if (get_compat_sigset(&s, uthese)) + return -EFAULT; + + if (uts) { + if (get_timespec64(&t, uts)) + return -EFAULT; + } + + ret = do_sigtimedwait(&s, &info, uts ? &t : NULL); + + if (ret > 0 && uinfo) { + if (copy_siginfo_to_user32(uinfo, &info)) + ret = -EFAULT; + } + + return ret; +} + +#ifdef CONFIG_COMPAT_32BIT_TIME COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait, compat_sigset_t __user *, uthese, struct compat_siginfo __user *, uinfo, struct old_timespec32 __user *, uts, compat_size_t, sigsetsize) @@ -3285,6 +3485,7 @@ COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait, compat_sigset_t __user *, uthese, return ret; } #endif +#endif /** * sys_kill - send a signal to a process @@ -3854,7 +4055,7 @@ SYSCALL_DEFINE3(sigaction, int, sig, if (act) { old_sigset_t mask; - if (!access_ok(VERIFY_READ, act, sizeof(*act)) || + if (!access_ok(act, sizeof(*act)) || __get_user(new_ka.sa.sa_handler, &act->sa_handler) || __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) || __get_user(new_ka.sa.sa_flags, &act->sa_flags) || @@ -3869,7 +4070,7 @@ SYSCALL_DEFINE3(sigaction, int, sig, ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); if (!ret && oact) { - if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || + if (!access_ok(oact, sizeof(*oact)) || __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) || __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || @@ -3891,7 +4092,7 @@ COMPAT_SYSCALL_DEFINE3(sigaction, int, sig, compat_uptr_t handler, restorer; if (act) { - if (!access_ok(VERIFY_READ, act, sizeof(*act)) || + if (!access_ok(act, sizeof(*act)) || __get_user(handler, &act->sa_handler) || __get_user(restorer, &act->sa_restorer) || __get_user(new_ka.sa.sa_flags, &act->sa_flags) || @@ -3909,7 +4110,7 @@ COMPAT_SYSCALL_DEFINE3(sigaction, int, sig, ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); if (!ret && oact) { - if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || + if (!access_ok(oact, sizeof(*oact)) || __put_user(ptr_to_compat(old_ka.sa.sa_handler), &oact->sa_handler) || __put_user(ptr_to_compat(old_ka.sa.sa_restorer), |