diff options
| -rw-r--r-- | include/linux/seccomp.h | 6 | ||||
| -rw-r--r-- | kernel/seccomp.c | 129 |
2 files changed, 41 insertions, 94 deletions
diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h index 9eaa7b34d6da..ecc296c137cd 100644 --- a/include/linux/seccomp.h +++ b/include/linux/seccomp.h @@ -35,12 +35,6 @@ static inline int secure_computing(const struct seccomp_data *sd) return __secure_computing(sd); return 0; } - -#define SECCOMP_PHASE1_OK 0 -#define SECCOMP_PHASE1_SKIP 1 - -extern u32 seccomp_phase1(struct seccomp_data *sd); -int seccomp_phase2(u32 phase1_result); #else extern void secure_computing_strict(int this_syscall); #endif diff --git a/kernel/seccomp.c b/kernel/seccomp.c index 06816290a212..14a37d71b612 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -173,7 +173,7 @@ static int seccomp_check_filter(struct sock_filter *filter, unsigned int flen) * * Returns valid seccomp BPF response codes. */ -static u32 seccomp_run_filters(struct seccomp_data *sd) +static u32 seccomp_run_filters(const struct seccomp_data *sd) { struct seccomp_data sd_local; u32 ret = SECCOMP_RET_ALLOW; @@ -554,20 +554,9 @@ void secure_computing_strict(int this_syscall) BUG(); } #else -int __secure_computing(const struct seccomp_data *sd) -{ - u32 phase1_result = seccomp_phase1(sd); - - if (likely(phase1_result == SECCOMP_PHASE1_OK)) - return 0; - else if (likely(phase1_result == SECCOMP_PHASE1_SKIP)) - return -1; - else - return seccomp_phase2(phase1_result); -} #ifdef CONFIG_SECCOMP_FILTER -static u32 __seccomp_phase1_filter(int this_syscall, struct seccomp_data *sd) +static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd) { u32 filter_ret, action; int data; @@ -599,10 +588,33 @@ static u32 __seccomp_phase1_filter(int this_syscall, struct seccomp_data *sd) goto skip; case SECCOMP_RET_TRACE: - return filter_ret; /* Save the rest for phase 2. */ + /* ENOSYS these calls if there is no tracer attached. */ + if (!ptrace_event_enabled(current, PTRACE_EVENT_SECCOMP)) { + syscall_set_return_value(current, + task_pt_regs(current), + -ENOSYS, 0); + goto skip; + } + + /* Allow the BPF to provide the event message */ + ptrace_event(PTRACE_EVENT_SECCOMP, data); + /* + * The delivery of a fatal signal during event + * notification may silently skip tracer notification. + * Terminating the task now avoids executing a system + * call that may not be intended. + */ + if (fatal_signal_pending(current)) + do_exit(SIGSYS); + /* Check if the tracer forced the syscall to be skipped. */ + this_syscall = syscall_get_nr(current, task_pt_regs(current)); + if (this_syscall < 0) + goto skip; + + return 0; case SECCOMP_RET_ALLOW: - return SECCOMP_PHASE1_OK; + return 0; case SECCOMP_RET_KILL: default: @@ -614,96 +626,37 @@ static u32 __seccomp_phase1_filter(int this_syscall, struct seccomp_data *sd) skip: audit_seccomp(this_syscall, 0, action); - return SECCOMP_PHASE1_SKIP; + return -1; +} +#else +static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd) +{ + BUG(); } #endif -/** - * seccomp_phase1() - run fast path seccomp checks on the current syscall - * @arg sd: The seccomp_data or NULL - * - * This only reads pt_regs via the syscall_xyz helpers. The only change - * it will make to pt_regs is via syscall_set_return_value, and it will - * only do that if it returns SECCOMP_PHASE1_SKIP. - * - * If sd is provided, it will not read pt_regs at all. - * - * It may also call do_exit or force a signal; these actions must be - * safe. - * - * If it returns SECCOMP_PHASE1_OK, the syscall passes checks and should - * be processed normally. - * - * If it returns SECCOMP_PHASE1_SKIP, then the syscall should not be - * invoked. In this case, seccomp_phase1 will have set the return value - * using syscall_set_return_value. - * - * If it returns anything else, then the return value should be passed - * to seccomp_phase2 from a context in which ptrace hooks are safe. - */ -u32 seccomp_phase1(struct seccomp_data *sd) +int __secure_computing(const struct seccomp_data *sd) { int mode = current->seccomp.mode; - int this_syscall = sd ? sd->nr : - syscall_get_nr(current, task_pt_regs(current)); + int this_syscall; if (config_enabled(CONFIG_CHECKPOINT_RESTORE) && unlikely(current->ptrace & PT_SUSPEND_SECCOMP)) - return SECCOMP_PHASE1_OK; + return 0; + + this_syscall = sd ? sd->nr : + syscall_get_nr(current, task_pt_regs(current)); switch (mode) { case SECCOMP_MODE_STRICT: __secure_computing_strict(this_syscall); /* may call do_exit */ - return SECCOMP_PHASE1_OK; -#ifdef CONFIG_SECCOMP_FILTER + return 0; case SECCOMP_MODE_FILTER: - return __seccomp_phase1_filter(this_syscall, sd); -#endif + return __seccomp_filter(this_syscall, sd); default: BUG(); } } - -/** - * seccomp_phase2() - finish slow path seccomp work for the current syscall - * @phase1_result: The return value from seccomp_phase1() - * - * This must be called from a context in which ptrace hooks can be used. - * - * Returns 0 if the syscall should be processed or -1 to skip the syscall. - */ -int seccomp_phase2(u32 phase1_result) -{ - struct pt_regs *regs = task_pt_regs(current); - u32 action = phase1_result & SECCOMP_RET_ACTION; - int data = phase1_result & SECCOMP_RET_DATA; - - BUG_ON(action != SECCOMP_RET_TRACE); - - audit_seccomp(syscall_get_nr(current, regs), 0, action); - - /* Skip these calls if there is no tracer. */ - if (!ptrace_event_enabled(current, PTRACE_EVENT_SECCOMP)) { - syscall_set_return_value(current, regs, - -ENOSYS, 0); - return -1; - } - - /* Allow the BPF to provide the event message */ - ptrace_event(PTRACE_EVENT_SECCOMP, data); - /* - * The delivery of a fatal signal during event - * notification may silently skip tracer notification. - * Terminating the task now avoids executing a system - * call that may not be intended. - */ - if (fatal_signal_pending(current)) - do_exit(SIGSYS); - if (syscall_get_nr(current, regs) < 0) - return -1; /* Explicit request to skip. */ - - return 0; -} #endif /* CONFIG_HAVE_ARCH_SECCOMP_FILTER */ long prctl_get_seccomp(void) |