From: Deepa Dinamani deepa.kernel@gmail.com
mainline inclusion from mainline-5.0-rc1 commit ded653ccbec0335a78fa7a7aff3ec9870349fafb category: feature bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=27 CVE: NA ---------------------------
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 deepa.kernel@gmail.com Signed-off-by: Arnd Bergmann arnd@arndb.de
Conflicts: include/linux/signal.h [ Patch ae7795bc6("signal: Distinguish between kernel_siginfo and siginfo") is not applied. ] kernel/signal.c [ Patch fb50f5a40("signal: Pair exports with their functions") is not applied. ]
Signed-off-by: Zhihao Cheng chengzhihao1@huawei.com Signed-off-by: yangerkun yangerkun@huawei.com Reviewed-by: zhangyi (F) yi.zhang@huawei.com Signed-off-by: Cheng Jian cj.chengjian@huawei.com --- 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 a404047ab453..9bd3dd57ea8f 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -2138,14 +2138,10 @@ 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)) { @@ -2208,14 +2204,9 @@ 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)) { diff --git a/fs/eventpoll.c b/fs/eventpoll.c index cf332e8f6bdf..3d879caff64c 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -2217,14 +2217,9 @@ SYSCALL_DEFINE6(epoll_pwait, 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);
@@ -2260,14 +2255,9 @@ COMPAT_SYSCALL_DEFINE6(epoll_pwait, int, epfd, * 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 be2f66c5cc8a..58594f0d5f67 100644 --- a/fs/select.c +++ b/fs/select.c @@ -714,16 +714,9 @@ 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); @@ -1056,16 +1049,9 @@ SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds, 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);
@@ -1318,15 +1304,9 @@ 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); @@ -1384,15 +1364,9 @@ COMPAT_SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, 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 189d0e111d57..c0476f7c4444 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -176,6 +176,10 @@ typedef struct { 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 0be5ce2375cb..2f489e525099 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 5ded8c6ac789..23beedc12eaa 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2816,6 +2816,51 @@ int sigprocmask(int how, sigset_t *set, sigset_t *oldset) return 0; }
+/* + * 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 + /** * sys_rt_sigprocmask - change the list of currently blocked signals * @how: whether to add, remove, or set signals