From ded653ccbec0335a78fa7a7aff3ec9870349fafb Mon Sep 17 00:00:00 2001 From: Deepa Dinamani Date: Wed, 19 Sep 2018 21:41:04 -0700 Subject: signal: Add set_user_sigmask() Refactor reading sigset from userspace and updating sigmask into an api. This is useful for versions of syscalls that pass in the sigmask and expect the current->sigmask to be changed during, and restored after, the execution of the syscall. With the advent of new y2038 syscalls in the subsequent patches, we add two more new versions of the syscalls (for pselect, ppoll, and io_pgetevents) in addition to the existing native and compat versions. Adding such an api reduces the logic that would need to be replicated otherwise. Note that the calls to sigprocmask() ignored the return value from the api as the function only returns an error on an invalid first argument that is hardcoded at these call sites. The updated logic uses set_current_blocked() instead. Signed-off-by: Deepa Dinamani Signed-off-by: Arnd Bergmann --- fs/aio.c | 23 +++++++---------------- 1 file changed, 7 insertions(+), 16 deletions(-) (limited to 'fs/aio.c') diff --git a/fs/aio.c b/fs/aio.c index 301e6314183b..6ddb63ee8eb6 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -2104,14 +2104,10 @@ SYSCALL_DEFINE6(io_pgetevents, if (usig && copy_from_user(&ksig, usig, sizeof(ksig))) return -EFAULT; - if (ksig.sigmask) { - if (ksig.sigsetsize != sizeof(sigset_t)) - return -EINVAL; - if (copy_from_user(&ksigmask, ksig.sigmask, sizeof(ksigmask))) - return -EFAULT; - sigdelsetmask(&ksigmask, sigmask(SIGKILL) | sigmask(SIGSTOP)); - sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); - } + + ret = set_user_sigmask(ksig.sigmask, &ksigmask, &sigsaved, ksig.sigsetsize); + if (ret) + return ret; ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL); if (signal_pending(current)) { @@ -2174,14 +2170,9 @@ COMPAT_SYSCALL_DEFINE6(io_pgetevents, if (usig && copy_from_user(&ksig, usig, sizeof(ksig))) return -EFAULT; - if (ksig.sigmask) { - if (ksig.sigsetsize != sizeof(compat_sigset_t)) - return -EINVAL; - if (get_compat_sigset(&ksigmask, ksig.sigmask)) - return -EFAULT; - sigdelsetmask(&ksigmask, sigmask(SIGKILL) | sigmask(SIGSTOP)); - sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); - } + ret = set_compat_user_sigmask(ksig.sigmask, &ksigmask, &sigsaved, ksig.sigsetsize); + if (ret) + return ret; ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL); if (signal_pending(current)) { -- cgit v1.2.3-55-g7522 From 854a6ed56839a40f6b5d02a2962f48841482eec4 Mon Sep 17 00:00:00 2001 From: Deepa Dinamani Date: Wed, 19 Sep 2018 21:41:05 -0700 Subject: signal: Add restore_user_sigmask() Refactor the logic to restore the sigmask before the syscall returns into an api. This is useful for versions of syscalls that pass in the sigmask and expect the current->sigmask to be changed during the execution and restored after the execution of the syscall. With the advent of new y2038 syscalls in the subsequent patches, we add two more new versions of the syscalls (for pselect, ppoll and io_pgetevents) in addition to the existing native and compat versions. Adding such an api reduces the logic that would need to be replicated otherwise. Signed-off-by: Deepa Dinamani Signed-off-by: Arnd Bergmann --- fs/aio.c | 29 +++++------------------- fs/eventpoll.c | 30 ++----------------------- fs/select.c | 60 +++++++------------------------------------------- include/linux/signal.h | 2 ++ kernel/signal.c | 33 +++++++++++++++++++++++++++ 5 files changed, 51 insertions(+), 103 deletions(-) (limited to 'fs/aio.c') diff --git a/fs/aio.c b/fs/aio.c index 6ddb63ee8eb6..39a1f2df6805 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -2110,18 +2110,9 @@ SYSCALL_DEFINE6(io_pgetevents, return ret; ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL); - if (signal_pending(current)) { - if (ksig.sigmask) { - current->saved_sigmask = sigsaved; - set_restore_sigmask(); - } - - if (!ret) - ret = -ERESTARTNOHAND; - } else { - if (ksig.sigmask) - sigprocmask(SIG_SETMASK, &sigsaved, NULL); - } + restore_user_sigmask(ksig.sigmask, &sigsaved); + if (signal_pending(current) && !ret) + ret = -ERESTARTNOHAND; return ret; } @@ -2175,17 +2166,9 @@ COMPAT_SYSCALL_DEFINE6(io_pgetevents, return ret; ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL); - if (signal_pending(current)) { - if (ksig.sigmask) { - current->saved_sigmask = sigsaved; - set_restore_sigmask(); - } - if (!ret) - ret = -ERESTARTNOHAND; - } else { - if (ksig.sigmask) - sigprocmask(SIG_SETMASK, &sigsaved, NULL); - } + restore_user_sigmask(ksig.sigmask, &sigsaved); + if (signal_pending(current) && !ret) + ret = -ERESTARTNOHAND; return ret; } diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 2d86eeba837b..8a5a1010886b 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -2229,20 +2229,7 @@ SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct epoll_event __user *, events, error = do_epoll_wait(epfd, events, maxevents, timeout); - /* - * If we changed the signal mask, we need to restore the original one. - * In case we've got a signal while waiting, we do not restore the - * signal mask yet, and we allow do_signal() to deliver the signal on - * the way back to userspace, before the signal mask is restored. - */ - if (sigmask) { - if (error == -EINTR) { - memcpy(¤t->saved_sigmask, &sigsaved, - sizeof(sigsaved)); - set_restore_sigmask(); - } else - set_current_blocked(&sigsaved); - } + restore_user_sigmask(sigmask, &sigsaved); return error; } @@ -2267,20 +2254,7 @@ COMPAT_SYSCALL_DEFINE6(epoll_pwait, int, epfd, err = do_epoll_wait(epfd, events, maxevents, timeout); - /* - * If we changed the signal mask, we need to restore the original one. - * In case we've got a signal while waiting, we do not restore the - * signal mask yet, and we allow do_signal() to deliver the signal on - * the way back to userspace, before the signal mask is restored. - */ - if (sigmask) { - if (err == -EINTR) { - memcpy(¤t->saved_sigmask, &sigsaved, - sizeof(sigsaved)); - set_restore_sigmask(); - } else - set_current_blocked(&sigsaved); - } + restore_user_sigmask(sigmask, &sigsaved); return err; } diff --git a/fs/select.c b/fs/select.c index 65c78b4147a2..eb9132520197 100644 --- a/fs/select.c +++ b/fs/select.c @@ -724,19 +724,7 @@ static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp, ret = core_sys_select(n, inp, outp, exp, to); ret = poll_select_copy_remaining(&end_time, tsp, 0, ret); - if (ret == -ERESTARTNOHAND) { - /* - * Don't restore the signal mask yet. Let do_signal() deliver - * the signal on the way back to userspace, before the signal - * mask is restored. - */ - if (sigmask) { - memcpy(¤t->saved_sigmask, &sigsaved, - sizeof(sigsaved)); - set_restore_sigmask(); - } - } else if (sigmask) - sigprocmask(SIG_SETMASK, &sigsaved, NULL); + restore_user_sigmask(sigmask, &sigsaved); return ret; } @@ -1060,21 +1048,11 @@ SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds, ret = do_sys_poll(ufds, nfds, to); + restore_user_sigmask(sigmask, &sigsaved); + /* We can restart this syscall, usually */ - if (ret == -EINTR) { - /* - * Don't restore the signal mask yet. Let do_signal() deliver - * the signal on the way back to userspace, before the signal - * mask is restored. - */ - if (sigmask) { - memcpy(¤t->saved_sigmask, &sigsaved, - sizeof(sigsaved)); - set_restore_sigmask(); - } + if (ret == -EINTR) ret = -ERESTARTNOHAND; - } else if (sigmask) - sigprocmask(SIG_SETMASK, &sigsaved, NULL); ret = poll_select_copy_remaining(&end_time, tsp, 0, ret); @@ -1316,19 +1294,7 @@ static long do_compat_pselect(int n, compat_ulong_t __user *inp, ret = compat_core_sys_select(n, inp, outp, exp, to); ret = compat_poll_select_copy_remaining(&end_time, tsp, 0, ret); - if (ret == -ERESTARTNOHAND) { - /* - * Don't restore the signal mask yet. Let do_signal() deliver - * the signal on the way back to userspace, before the signal - * mask is restored. - */ - if (sigmask) { - memcpy(¤t->saved_sigmask, &sigsaved, - sizeof(sigsaved)); - set_restore_sigmask(); - } - } else if (sigmask) - sigprocmask(SIG_SETMASK, &sigsaved, NULL); + restore_user_sigmask(sigmask, &sigsaved); return ret; } @@ -1375,21 +1341,11 @@ COMPAT_SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, ret = do_sys_poll(ufds, nfds, to); + restore_user_sigmask(sigmask, &sigsaved); + /* We can restart this syscall, usually */ - if (ret == -EINTR) { - /* - * Don't restore the signal mask yet. Let do_signal() deliver - * the signal on the way back to userspace, before the signal - * mask is restored. - */ - if (sigmask) { - memcpy(¤t->saved_sigmask, &sigsaved, - sizeof(sigsaved)); - set_restore_sigmask(); - } + if (ret == -EINTR) ret = -ERESTARTNOHAND; - } else if (sigmask) - sigprocmask(SIG_SETMASK, &sigsaved, NULL); ret = compat_poll_select_copy_remaining(&end_time, tsp, 0, ret); diff --git a/include/linux/signal.h b/include/linux/signal.h index ce14b951befb..cc7e2c1cd444 100644 --- a/include/linux/signal.h +++ b/include/linux/signal.h @@ -275,6 +275,8 @@ extern int __group_send_sig_info(int, struct kernel_siginfo *, struct task_struc 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); 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 811b5d440617..3c8ea7a328e0 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2780,6 +2780,39 @@ int set_compat_user_sigmask(const compat_sigset_t __user *usigmask, 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 -- cgit v1.2.3-55-g7522 From 7a35397f8c06bffd4c747537095321ff971045a5 Mon Sep 17 00:00:00 2001 From: Deepa Dinamani Date: Wed, 19 Sep 2018 21:41:08 -0700 Subject: io_pgetevents: use __kernel_timespec struct timespec is not y2038 safe. struct __kernel_timespec is the new y2038 safe structure for all syscalls that are using struct timespec. Update io_pgetevents interfaces to use struct __kernel_timespec. sigset_t also has different representations on 32 bit and 64 bit architectures. Hence, we need to support the following different syscalls: New y2038 safe syscalls: (Controlled by CONFIG_64BIT_TIME for 32 bit ABIs) Native 64 bit(unchanged) and native 32 bit : sys_io_pgetevents Compat : compat_sys_io_pgetevents_time64 Older y2038 unsafe syscalls: (Controlled by CONFIG_32BIT_COMPAT_TIME for 32 bit ABIs) Native 32 bit : sys_io_pgetevents_time32 Compat : compat_sys_io_pgetevents Note that io_getevents syscalls do not have a y2038 safe solution. Signed-off-by: Deepa Dinamani Signed-off-by: Arnd Bergmann --- fs/aio.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++-- include/linux/compat.h | 6 ++++ include/linux/syscalls.h | 10 ++++-- 3 files changed, 95 insertions(+), 5 deletions(-) (limited to 'fs/aio.c') diff --git a/fs/aio.c b/fs/aio.c index 39a1f2df6805..62a0c560cd3d 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -2062,11 +2062,13 @@ static long do_io_getevents(aio_context_t ctx_id, * specifies an infinite timeout. Note that the timeout pointed to by * timeout is relative. Will fail with -ENOSYS if not implemented. */ +#if !defined(CONFIG_64BIT_TIME) || defined(CONFIG_64BIT) + SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id, long, min_nr, long, nr, struct io_event __user *, events, - struct timespec __user *, timeout) + struct __kernel_timespec __user *, timeout) { struct timespec64 ts; int ret; @@ -2080,6 +2082,8 @@ SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id, return ret; } +#endif + struct __aio_sigset { const sigset_t __user *sigmask; size_t sigsetsize; @@ -2090,7 +2094,7 @@ SYSCALL_DEFINE6(io_pgetevents, long, min_nr, long, nr, struct io_event __user *, events, - struct timespec __user *, timeout, + struct __kernel_timespec __user *, timeout, const struct __aio_sigset __user *, usig) { struct __aio_sigset ksig = { NULL, }; @@ -2104,6 +2108,39 @@ SYSCALL_DEFINE6(io_pgetevents, if (usig && copy_from_user(&ksig, usig, sizeof(ksig))) return -EFAULT; + ret = set_user_sigmask(ksig.sigmask, &ksigmask, &sigsaved, ksig.sigsetsize); + if (ret) + return ret; + + ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL); + restore_user_sigmask(ksig.sigmask, &sigsaved); + if (signal_pending(current) && !ret) + ret = -ERESTARTNOHAND; + + return ret; +} + +#if defined(CONFIG_COMPAT_32BIT_TIME) && !defined(CONFIG_64BIT) + +SYSCALL_DEFINE6(io_pgetevents_time32, + aio_context_t, ctx_id, + long, min_nr, + long, nr, + struct io_event __user *, events, + struct old_timespec32 __user *, timeout, + const struct __aio_sigset __user *, usig) +{ + struct __aio_sigset ksig = { NULL, }; + sigset_t ksigmask, sigsaved; + struct timespec64 ts; + int ret; + + if (timeout && unlikely(get_old_timespec32(&ts, timeout))) + return -EFAULT; + + if (usig && copy_from_user(&ksig, usig, sizeof(ksig))) + return -EFAULT; + ret = set_user_sigmask(ksig.sigmask, &ksigmask, &sigsaved, ksig.sigsetsize); if (ret) @@ -2117,7 +2154,10 @@ SYSCALL_DEFINE6(io_pgetevents, return ret; } -#ifdef CONFIG_COMPAT +#endif + +#if defined(CONFIG_COMPAT_32BIT_TIME) + COMPAT_SYSCALL_DEFINE5(io_getevents, compat_aio_context_t, ctx_id, compat_long_t, min_nr, compat_long_t, nr, @@ -2136,12 +2176,17 @@ COMPAT_SYSCALL_DEFINE5(io_getevents, compat_aio_context_t, ctx_id, return ret; } +#endif + +#ifdef CONFIG_COMPAT struct __compat_aio_sigset { compat_sigset_t __user *sigmask; compat_size_t sigsetsize; }; +#if defined(CONFIG_COMPAT_32BIT_TIME) + COMPAT_SYSCALL_DEFINE6(io_pgetevents, compat_aio_context_t, ctx_id, compat_long_t, min_nr, @@ -2172,4 +2217,37 @@ COMPAT_SYSCALL_DEFINE6(io_pgetevents, return ret; } + +#endif + +COMPAT_SYSCALL_DEFINE6(io_pgetevents_time64, + compat_aio_context_t, ctx_id, + compat_long_t, min_nr, + compat_long_t, nr, + struct io_event __user *, events, + struct __kernel_timespec __user *, timeout, + const struct __compat_aio_sigset __user *, usig) +{ + struct __compat_aio_sigset ksig = { NULL, }; + sigset_t ksigmask, sigsaved; + struct timespec64 t; + int ret; + + if (timeout && get_timespec64(&t, timeout)) + return -EFAULT; + + if (usig && copy_from_user(&ksig, usig, sizeof(ksig))) + return -EFAULT; + + ret = set_compat_user_sigmask(ksig.sigmask, &ksigmask, &sigsaved, ksig.sigsetsize); + if (ret) + return ret; + + ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL); + restore_user_sigmask(ksig.sigmask, &sigsaved); + if (signal_pending(current) && !ret) + ret = -ERESTARTNOHAND; + + return ret; +} #endif diff --git a/include/linux/compat.h b/include/linux/compat.h index 5776733b763f..8be8daa38c9a 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -562,6 +562,12 @@ asmlinkage long compat_sys_io_pgetevents(compat_aio_context_t ctx_id, struct io_event __user *events, struct old_timespec32 __user *timeout, const struct __compat_aio_sigset __user *usig); +asmlinkage long compat_sys_io_pgetevents_time64(compat_aio_context_t ctx_id, + compat_long_t min_nr, + compat_long_t nr, + struct io_event __user *events, + struct __kernel_timespec __user *timeout, + const struct __compat_aio_sigset __user *usig); /* fs/cookies.c */ asmlinkage long compat_sys_lookup_dcookie(u32, u32, char __user *, compat_size_t); diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 934e58e0dfa4..a27cf407de92 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -296,12 +296,18 @@ asmlinkage long sys_io_getevents(aio_context_t ctx_id, long min_nr, long nr, struct io_event __user *events, - struct timespec __user *timeout); + struct __kernel_timespec __user *timeout); asmlinkage long sys_io_pgetevents(aio_context_t ctx_id, long min_nr, long nr, struct io_event __user *events, - struct timespec __user *timeout, + struct __kernel_timespec __user *timeout, + const struct __aio_sigset *sig); +asmlinkage long sys_io_pgetevents_time32(aio_context_t ctx_id, + long min_nr, + long nr, + struct io_event __user *events, + struct old_timespec32 __user *timeout, const struct __aio_sigset *sig); /* fs/xattr.c */ -- cgit v1.2.3-55-g7522