diff options
Diffstat (limited to 'kernel/seccomp.c')
| -rw-r--r-- | kernel/seccomp.c | 49 |
1 files changed, 29 insertions, 20 deletions
diff --git a/kernel/seccomp.c b/kernel/seccomp.c index 7bbb408431eb..41aa761c7738 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -29,13 +29,11 @@ #include <linux/syscalls.h> #include <linux/sysctl.h> +#include <asm/syscall.h> + /* Not exposed in headers: strictly internal use only. */ #define SECCOMP_MODE_DEAD (SECCOMP_MODE_FILTER + 1) -#ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER -#include <asm/syscall.h> -#endif - #ifdef CONFIG_SECCOMP_FILTER #include <linux/file.h> #include <linux/filter.h> @@ -576,6 +574,9 @@ void seccomp_filter_release(struct task_struct *tsk) if (WARN_ON((tsk->flags & PF_EXITING) == 0)) return; + if (READ_ONCE(tsk->seccomp.filter) == NULL) + return; + spin_lock_irq(&tsk->sighand->siglock); orig = tsk->seccomp.filter; /* Detach task from its filter tree. */ @@ -601,6 +602,13 @@ static inline void seccomp_sync_threads(unsigned long flags) BUG_ON(!mutex_is_locked(¤t->signal->cred_guard_mutex)); assert_spin_locked(¤t->sighand->siglock); + /* + * Don't touch any of the threads if the process is being killed. + * This allows for a lockless check in seccomp_filter_release. + */ + if (current->signal->flags & SIGNAL_GROUP_EXIT) + return; + /* Synchronize all threads. */ caller = current; for_each_thread(caller, thread) { @@ -1074,6 +1082,13 @@ void secure_computing_strict(int this_syscall) else BUG(); } +int __secure_computing(void) +{ + int this_syscall = syscall_get_nr(current, current_pt_regs()); + + secure_computing_strict(this_syscall); + return 0; +} #else #ifdef CONFIG_SECCOMP_FILTER @@ -1225,13 +1240,12 @@ out: return -1; } -static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd, - const bool recheck_after_trace) +static int __seccomp_filter(int this_syscall, const bool recheck_after_trace) { u32 filter_ret, action; + struct seccomp_data sd; struct seccomp_filter *match = NULL; int data; - struct seccomp_data sd_local; /* * Make sure that any changes to mode from another thread have @@ -1239,12 +1253,9 @@ static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd, */ smp_rmb(); - if (!sd) { - populate_seccomp_data(&sd_local); - sd = &sd_local; - } + populate_seccomp_data(&sd); - filter_ret = seccomp_run_filters(sd, &match); + filter_ret = seccomp_run_filters(&sd, &match); data = filter_ret & SECCOMP_RET_DATA; action = filter_ret & SECCOMP_RET_ACTION_FULL; @@ -1302,13 +1313,13 @@ static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd, * a reload of all registers. This does not goto skip since * a skip would have already been reported. */ - if (__seccomp_filter(this_syscall, NULL, true)) + if (__seccomp_filter(this_syscall, true)) return -1; return 0; case SECCOMP_RET_USER_NOTIF: - if (seccomp_do_user_notification(this_syscall, match, sd)) + if (seccomp_do_user_notification(this_syscall, match, &sd)) goto skip; return 0; @@ -1350,8 +1361,7 @@ skip: return -1; } #else -static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd, - const bool recheck_after_trace) +static int __seccomp_filter(int this_syscall, const bool recheck_after_trace) { BUG(); @@ -1359,7 +1369,7 @@ static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd, } #endif -int __secure_computing(const struct seccomp_data *sd) +int __secure_computing(void) { int mode = current->seccomp.mode; int this_syscall; @@ -1368,15 +1378,14 @@ int __secure_computing(const struct seccomp_data *sd) unlikely(current->ptrace & PT_SUSPEND_SECCOMP)) return 0; - this_syscall = sd ? sd->nr : - syscall_get_nr(current, current_pt_regs()); + this_syscall = syscall_get_nr(current, current_pt_regs()); switch (mode) { case SECCOMP_MODE_STRICT: __secure_computing_strict(this_syscall); /* may call do_exit */ return 0; case SECCOMP_MODE_FILTER: - return __seccomp_filter(this_syscall, sd, false); + return __seccomp_filter(this_syscall, false); /* Surviving SECCOMP_RET_KILL_* must be proactively impossible. */ case SECCOMP_MODE_DEAD: WARN_ON_ONCE(1); |