From f12f95624a28ea687ecc97cc57e066a7eef6818c Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 16 Jul 2019 16:29:53 -0700 Subject: [PATCH 0620/2944] signal: simplify set_user_sigmask/restore_user_sigmask commit b772434be0891ed1081a08ae7cfd4666728f8e82 upstream. task->saved_sigmask and ->restore_sigmask are only used in the ret-from- syscall paths. This means that set_user_sigmask() can save ->blocked in ->saved_sigmask and do set_restore_sigmask() to indicate that ->blocked was modified. This way the callers do not need 2 sigset_t's passed to set/restore and restore_user_sigmask() renamed to restore_saved_sigmask_unless() turns into the trivial helper which just calls restore_saved_sigmask(). Link: http://lkml.kernel.org/r/20190606113206.GA9464@redhat.com Signed-off-by: Oleg Nesterov Cc: Deepa Dinamani Cc: Arnd Bergmann Cc: Jens Axboe Cc: Davidlohr Bueso Cc: Eric Wong Cc: Jason Baron Cc: Thomas Gleixner Cc: Al Viro Cc: Eric W. Biederman Cc: David Laight Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Joseph Qi Reviewed-by: Xiaoguang Wang --- fs/aio.c | 10 +++---- fs/eventpoll.c | 12 +++----- fs/io_uring.c | 11 ++----- fs/select.c | 20 +++++-------- include/linux/compat.h | 3 +- include/linux/sched/signal.h | 12 ++++++-- include/linux/signal.h | 4 --- kernel/signal.c | 69 ++++++++++++-------------------------------- 8 files changed, 49 insertions(+), 92 deletions(-) diff --git a/fs/aio.c b/fs/aio.c index 63c5481..2a5ea34 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -2094,7 +2094,6 @@ struct __aio_sigset { const struct __aio_sigset __user *, usig) { struct __aio_sigset ksig = { NULL, }; - sigset_t ksigmask, sigsaved; struct timespec64 ts; bool interrupted; int ret; @@ -2106,14 +2105,14 @@ struct __aio_sigset { return -EFAULT; - ret = set_user_sigmask(ksig.sigmask, &ksigmask, &sigsaved, ksig.sigsetsize); + ret = set_user_sigmask(ksig.sigmask, ksig.sigsetsize); if (ret) return ret; ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL); interrupted = signal_pending(current); - restore_user_sigmask(ksig.sigmask, &sigsaved, interrupted); + restore_saved_sigmask_unless(interrupted); if (interrupted && !ret) ret = -ERESTARTNOHAND; @@ -2154,7 +2153,6 @@ struct __compat_aio_sigset { const struct __compat_aio_sigset __user *, usig) { struct __compat_aio_sigset ksig = { NULL, }; - sigset_t ksigmask, sigsaved; struct timespec64 t; bool interrupted; int ret; @@ -2165,14 +2163,14 @@ struct __compat_aio_sigset { if (usig && copy_from_user(&ksig, usig, sizeof(ksig))) return -EFAULT; - ret = set_compat_user_sigmask(ksig.sigmask, &ksigmask, &sigsaved, ksig.sigsetsize); + ret = set_compat_user_sigmask(ksig.sigmask, ksig.sigsetsize); if (ret) return ret; ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL); interrupted = signal_pending(current); - restore_user_sigmask(ksig.sigmask, &sigsaved, interrupted); + restore_saved_sigmask_unless(interrupted); if (interrupted && !ret) ret = -ERESTARTNOHAND; diff --git a/fs/eventpoll.c b/fs/eventpoll.c index c6930af..cf9f9c6 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -2217,19 +2217,17 @@ static int do_epoll_wait(int epfd, struct epoll_event __user *events, size_t, sigsetsize) { int error; - sigset_t ksigmask, sigsaved; /* * If the caller wants a certain signal mask to be set during the wait, * we apply it here. */ - error = set_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize); + error = set_user_sigmask(sigmask, sigsetsize); if (error) return error; error = do_epoll_wait(epfd, events, maxevents, timeout); - - restore_user_sigmask(sigmask, &sigsaved, error == -EINTR); + restore_saved_sigmask_unless(error == -EINTR); return error; } @@ -2242,19 +2240,17 @@ static int do_epoll_wait(int epfd, struct epoll_event __user *events, compat_size_t, sigsetsize) { long err; - sigset_t ksigmask, sigsaved; /* * If the caller wants a certain signal mask to be set during the wait, * we apply it here. */ - err = set_compat_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize); + err = set_compat_user_sigmask(sigmask, sigsetsize); if (err) return err; err = do_epoll_wait(epfd, events, maxevents, timeout); - - restore_user_sigmask(sigmask, &sigsaved, err == -EINTR); + restore_saved_sigmask_unless(err == -EINTR); return err; } diff --git a/fs/io_uring.c b/fs/io_uring.c index 357e811..6407148 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2406,7 +2406,6 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, const sigset_t __user *sig, size_t sigsz) { struct io_cq_ring *ring = ctx->cq_ring; - sigset_t ksigmask, sigsaved; int ret; if (io_cqring_events(ring) >= min_events) @@ -2416,21 +2415,17 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, #ifdef CONFIG_COMPAT if (in_compat_syscall()) ret = set_compat_user_sigmask((const compat_sigset_t __user *)sig, - &ksigmask, &sigsaved, sigsz); + sigsz); else #endif - ret = set_user_sigmask(sig, &ksigmask, - &sigsaved, sigsz); + ret = set_user_sigmask(sig, sigsz); if (ret) return ret; } ret = wait_event_interruptible(ctx->wait, io_cqring_events(ring) >= min_events); - - if (sig) - restore_user_sigmask(sig, &sigsaved, ret == -ERESTARTSYS); - + restore_saved_sigmask_unless(ret == -ERESTARTSYS); if (ret == -ERESTARTSYS) ret = -EINTR; diff --git a/fs/select.c b/fs/select.c index 8f850b2..756761b 100644 --- a/fs/select.c +++ b/fs/select.c @@ -704,7 +704,6 @@ static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp, fd_set __user *exp, struct timespec __user *tsp, const sigset_t __user *sigmask, size_t sigsetsize) { - sigset_t ksigmask, sigsaved; struct timespec64 ts, end_time, *to = NULL; int ret; @@ -717,12 +716,12 @@ static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp, return -EINVAL; } - ret = set_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize); + ret = set_user_sigmask(sigmask, sigsetsize); if (ret) return ret; ret = core_sys_select(n, inp, outp, exp, to); - restore_user_sigmask(sigmask, &sigsaved, ret == -ERESTARTNOHAND); + restore_saved_sigmask_unless(ret == -ERESTARTNOHAND); ret = poll_select_copy_remaining(&end_time, tsp, 0, ret); return ret; @@ -1028,7 +1027,6 @@ static long do_restart_poll(struct restart_block *restart_block) struct timespec __user *, tsp, const sigset_t __user *, sigmask, size_t, sigsetsize) { - sigset_t ksigmask, sigsaved; struct timespec64 ts, end_time, *to = NULL; int ret; @@ -1041,13 +1039,13 @@ static long do_restart_poll(struct restart_block *restart_block) return -EINVAL; } - ret = set_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize); + ret = set_user_sigmask(sigmask, sigsetsize); if (ret) return ret; ret = do_sys_poll(ufds, nfds, to); - restore_user_sigmask(sigmask, &sigsaved, ret == -EINTR); + restore_saved_sigmask_unless(ret == -EINTR); /* We can restart this syscall, usually */ if (ret == -EINTR) ret = -ERESTARTNOHAND; @@ -1272,7 +1270,6 @@ static long do_compat_pselect(int n, compat_ulong_t __user *inp, struct compat_timespec __user *tsp, compat_sigset_t __user *sigmask, compat_size_t sigsetsize) { - sigset_t ksigmask, sigsaved; struct timespec64 ts, end_time, *to = NULL; int ret; @@ -1285,12 +1282,12 @@ static long do_compat_pselect(int n, compat_ulong_t __user *inp, return -EINVAL; } - ret = set_compat_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize); + ret = set_compat_user_sigmask(sigmask, sigsetsize); if (ret) return ret; ret = compat_core_sys_select(n, inp, outp, exp, to); - restore_user_sigmask(sigmask, &sigsaved, ret == -ERESTARTNOHAND); + restore_saved_sigmask_unless(ret == -ERESTARTNOHAND); ret = compat_poll_select_copy_remaining(&end_time, tsp, 0, ret); return ret; @@ -1319,7 +1316,6 @@ static long do_compat_pselect(int n, compat_ulong_t __user *inp, unsigned int, nfds, struct compat_timespec __user *, tsp, const compat_sigset_t __user *, sigmask, compat_size_t, sigsetsize) { - sigset_t ksigmask, sigsaved; struct timespec64 ts, end_time, *to = NULL; int ret; @@ -1332,13 +1328,13 @@ static long do_compat_pselect(int n, compat_ulong_t __user *inp, return -EINVAL; } - ret = set_compat_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize); + ret = set_compat_user_sigmask(sigmask, sigsetsize); if (ret) return ret; ret = do_sys_poll(ufds, nfds, to); - restore_user_sigmask(sigmask, &sigsaved, ret == -EINTR); + restore_saved_sigmask_unless(ret == -EINTR); /* We can restart this syscall, usually */ if (ret == -EINTR) ret = -ERESTARTNOHAND; diff --git a/include/linux/compat.h b/include/linux/compat.h index 8f846d0..2566d9f 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -176,8 +176,7 @@ struct compat_timex { compat_sigset_word sig[_COMPAT_NSIG_WORDS]; } compat_sigset_t; -int set_compat_user_sigmask(const compat_sigset_t __user *usigmask, - sigset_t *set, sigset_t *oldset, +int set_compat_user_sigmask(const compat_sigset_t __user *umask, size_t sigsetsize); struct compat_sigaction { diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h index 5889abb..698d1c4 100644 --- a/include/linux/sched/signal.h +++ b/include/linux/sched/signal.h @@ -418,7 +418,6 @@ static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume) static inline void set_restore_sigmask(void) { set_thread_flag(TIF_RESTORE_SIGMASK); - WARN_ON(!test_thread_flag(TIF_SIGPENDING)); } static inline void clear_tsk_restore_sigmask(struct task_struct *tsk) @@ -449,7 +448,6 @@ static inline bool test_and_clear_restore_sigmask(void) static inline void set_restore_sigmask(void) { current->restore_sigmask = true; - WARN_ON(!test_thread_flag(TIF_SIGPENDING)); } static inline void clear_tsk_restore_sigmask(struct task_struct *tsk) { @@ -482,6 +480,16 @@ static inline void restore_saved_sigmask(void) __set_current_blocked(¤t->saved_sigmask); } +extern int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize); + +static inline void restore_saved_sigmask_unless(bool interrupted) +{ + if (interrupted) + WARN_ON(!test_thread_flag(TIF_SIGPENDING)); + else + restore_saved_sigmask(); +} + static inline sigset_t *sigmask_to_save(void) { sigset_t *res = ¤t->blocked; diff --git a/include/linux/signal.h b/include/linux/signal.h index a88a174..e4d0146 100644 --- a/include/linux/signal.h +++ b/include/linux/signal.h @@ -263,10 +263,6 @@ extern int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p, enum pid_type type); extern int __group_send_sig_info(int, struct siginfo *, struct task_struct *); extern int sigprocmask(int, sigset_t *, sigset_t *); -extern int set_user_sigmask(const sigset_t __user *usigmask, sigset_t *set, - sigset_t *oldset, size_t sigsetsize); -extern void restore_user_sigmask(const void __user *usigmask, - sigset_t *sigsaved, bool interrupted); extern void set_current_blocked(sigset_t *); extern void __set_current_blocked(const sigset_t *); extern int show_unhandled_signals; diff --git a/kernel/signal.c b/kernel/signal.c index b39061e..598d09a 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2744,80 +2744,49 @@ static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset) * * 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. + * + * Note that it does set_restore_sigmask() in advance, so it must be always + * paired with restore_saved_sigmask_unless() before return from syscall. */ -int set_user_sigmask(const sigset_t __user *usigmask, sigset_t *set, - sigset_t *oldset, size_t sigsetsize) +int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize) { - if (!usigmask) - return 0; + sigset_t kmask; + if (!umask) + return 0; if (sigsetsize != sizeof(sigset_t)) return -EINVAL; - if (copy_from_user(set, usigmask, sizeof(sigset_t))) + if (copy_from_user(&kmask, umask, sizeof(sigset_t))) return -EFAULT; - *oldset = current->blocked; - set_current_blocked(set); + set_restore_sigmask(); + current->saved_sigmask = current->blocked; + set_current_blocked(&kmask); 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, +int set_compat_user_sigmask(const compat_sigset_t __user *umask, size_t sigsetsize) { - if (!usigmask) - return 0; + sigset_t kmask; + if (!umask) + return 0; if (sigsetsize != sizeof(compat_sigset_t)) return -EINVAL; - if (get_compat_sigset(set, usigmask)) + if (get_compat_sigset(&kmask, umask)) return -EFAULT; - *oldset = current->blocked; - set_current_blocked(set); + set_restore_sigmask(); + current->saved_sigmask = current->blocked; + set_current_blocked(&kmask); 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, - bool interrupted) -{ - - 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 (interrupted) { - 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); - /** * set_current_blocked - change current->blocked mask * @newset: new mask -- 1.8.3.1