From 2e132aa11ddf867216926099ee4ec34347832497 Mon Sep 17 00:00:00 2001 From: Deepa Dinamani Date: Wed, 19 Sep 2018 21:41:04 -0700 Subject: [PATCH 0395/2944] signal: Add set_user_sigmask() commit ded653ccbec0335a78fa7a7aff3ec9870349fafb upstream. 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 Signed-off-by: Joseph Qi Reviewed-by: Xiaoguang Wang Acked-by: Caspar Zhang --- fs/aio.c | 23 +++++++---------------- fs/eventpoll.c | 22 ++++++---------------- fs/select.c | 50 ++++++++++++-------------------------------------- include/linux/compat.h | 4 ++++ include/linux/signal.h | 2 ++ kernel/signal.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 76 insertions(+), 70 deletions(-) diff --git a/fs/aio.c b/fs/aio.c index 911e230..7ee15d0 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -2103,14 +2103,10 @@ struct __aio_sigset { 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)) { @@ -2173,14 +2169,9 @@ struct __compat_aio_sigset { 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)) { diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 58f48ea..2502b9f 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -2223,14 +2223,9 @@ static int do_epoll_wait(int epfd, struct epoll_event __user *events, * If the caller wants a certain signal mask to be set during the wait, * we apply it here. */ - if (sigmask) { - if (sigsetsize != sizeof(sigset_t)) - return -EINVAL; - if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) - return -EFAULT; - sigsaved = current->blocked; - set_current_blocked(&ksigmask); - } + error = set_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize); + if (error) + return error; error = do_epoll_wait(epfd, events, maxevents, timeout); @@ -2266,14 +2261,9 @@ static int do_epoll_wait(int epfd, struct epoll_event __user *events, * If the caller wants a certain signal mask to be set during the wait, * we apply it here. */ - if (sigmask) { - if (sigsetsize != sizeof(compat_sigset_t)) - return -EINVAL; - if (get_compat_sigset(&ksigmask, sigmask)) - return -EFAULT; - sigsaved = current->blocked; - set_current_blocked(&ksigmask); - } + err = set_compat_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize); + if (err) + return err; err = do_epoll_wait(epfd, events, maxevents, timeout); diff --git a/fs/select.c b/fs/select.c index 4a6b6e4..3665847 100644 --- a/fs/select.c +++ b/fs/select.c @@ -717,16 +717,9 @@ static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp, return -EINVAL; } - if (sigmask) { - /* XXX: Don't preclude handling different sized sigset_t's. */ - if (sigsetsize != sizeof(sigset_t)) - return -EINVAL; - if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) - return -EFAULT; - - sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP)); - sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); - } + ret = set_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize); + if (ret) + return ret; ret = core_sys_select(n, inp, outp, exp, to); ret = poll_select_copy_remaining(&end_time, tsp, 0, ret); @@ -1061,16 +1054,9 @@ static long do_restart_poll(struct restart_block *restart_block) return -EINVAL; } - if (sigmask) { - /* XXX: Don't preclude handling different sized sigset_t's. */ - if (sigsetsize != sizeof(sigset_t)) - return -EINVAL; - if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) - return -EFAULT; - - sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP)); - sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); - } + ret = set_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize); + if (ret) + return ret; ret = do_sys_poll(ufds, nfds, to); @@ -1323,15 +1309,9 @@ static long do_compat_pselect(int n, compat_ulong_t __user *inp, return -EINVAL; } - if (sigmask) { - if (sigsetsize != sizeof(compat_sigset_t)) - return -EINVAL; - if (get_compat_sigset(&ksigmask, sigmask)) - return -EFAULT; - - sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP)); - sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); - } + ret = set_compat_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize); + if (ret) + return ret; ret = compat_core_sys_select(n, inp, outp, exp, to); ret = compat_poll_select_copy_remaining(&end_time, tsp, 0, ret); @@ -1389,15 +1369,9 @@ static long do_compat_pselect(int n, compat_ulong_t __user *inp, return -EINVAL; } - if (sigmask) { - if (sigsetsize != sizeof(compat_sigset_t)) - return -EINVAL; - if (get_compat_sigset(&ksigmask, sigmask)) - return -EFAULT; - - sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP)); - sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); - } + ret = set_compat_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize); + if (ret) + return ret; ret = do_sys_poll(ufds, nfds, to); diff --git a/include/linux/compat.h b/include/linux/compat.h index de0c13b..8f846d0 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -176,6 +176,10 @@ 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, + size_t sigsetsize); + struct compat_sigaction { #ifndef __ARCH_HAS_IRIX_SIGACTION compat_uptr_t sa_handler; diff --git a/include/linux/signal.h b/include/linux/signal.h index e4d0146..296b87b 100644 --- a/include/linux/signal.h +++ b/include/linux/signal.h @@ -263,6 +263,8 @@ 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 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 7278302..a9b8e57 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2739,6 +2739,51 @@ static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset) recalc_sigpending(); } +/* + * 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 + /** * set_current_blocked - change current->blocked mask * @newset: new mask -- 1.8.3.1