diff options
| -rw-r--r-- | include/linux/seccomp.h | 3 | ||||
| -rw-r--r-- | include/uapi/linux/seccomp.h | 1 | ||||
| -rw-r--r-- | kernel/seccomp.c | 14 | ||||
| -rw-r--r-- | tools/testing/selftests/seccomp/seccomp_bpf.c | 74 |
4 files changed, 86 insertions, 6 deletions
diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h index 03583b6d1416..4192369b8418 100644 --- a/include/linux/seccomp.h +++ b/include/linux/seccomp.h @@ -7,7 +7,8 @@ #define SECCOMP_FILTER_FLAG_MASK (SECCOMP_FILTER_FLAG_TSYNC | \ SECCOMP_FILTER_FLAG_LOG | \ SECCOMP_FILTER_FLAG_SPEC_ALLOW | \ - SECCOMP_FILTER_FLAG_NEW_LISTENER) + SECCOMP_FILTER_FLAG_NEW_LISTENER | \ + SECCOMP_FILTER_FLAG_TSYNC_ESRCH) #ifdef CONFIG_SECCOMP diff --git a/include/uapi/linux/seccomp.h b/include/uapi/linux/seccomp.h index be84d87f1f46..c1735455bc53 100644 --- a/include/uapi/linux/seccomp.h +++ b/include/uapi/linux/seccomp.h @@ -22,6 +22,7 @@ #define SECCOMP_FILTER_FLAG_LOG (1UL << 1) #define SECCOMP_FILTER_FLAG_SPEC_ALLOW (1UL << 2) #define SECCOMP_FILTER_FLAG_NEW_LISTENER (1UL << 3) +#define SECCOMP_FILTER_FLAG_TSYNC_ESRCH (1UL << 4) /* * All BPF programs must return a 32-bit value. diff --git a/kernel/seccomp.c b/kernel/seccomp.c index b6ea3dcb57bf..29022c1bbe18 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -528,8 +528,12 @@ static long seccomp_attach_filter(unsigned int flags, int ret; ret = seccomp_can_sync_threads(); - if (ret) - return ret; + if (ret) { + if (flags & SECCOMP_FILTER_FLAG_TSYNC_ESRCH) + return -ESRCH; + else + return ret; + } } /* Set log flag, if present. */ @@ -1288,10 +1292,12 @@ static long seccomp_set_mode_filter(unsigned int flags, * In the successful case, NEW_LISTENER returns the new listener fd. * But in the failure case, TSYNC returns the thread that died. If you * combine these two flags, there's no way to tell whether something - * succeeded or failed. So, let's disallow this combination. + * succeeded or failed. So, let's disallow this combination if the user + * has not explicitly requested no errors from TSYNC. */ if ((flags & SECCOMP_FILTER_FLAG_TSYNC) && - (flags & SECCOMP_FILTER_FLAG_NEW_LISTENER)) + (flags & SECCOMP_FILTER_FLAG_NEW_LISTENER) && + ((flags & SECCOMP_FILTER_FLAG_TSYNC_ESRCH) == 0)) return -EINVAL; /* Prepare the new filter before holding any locks. */ diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c index ee1b727ede04..a9ad3bd8b2ad 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -212,6 +212,10 @@ struct seccomp_notif_sizes { #define SECCOMP_USER_NOTIF_FLAG_CONTINUE 0x00000001 #endif +#ifndef SECCOMP_FILTER_FLAG_TSYNC_ESRCH +#define SECCOMP_FILTER_FLAG_TSYNC_ESRCH (1UL << 4) +#endif + #ifndef seccomp int seccomp(unsigned int op, unsigned int flags, void *args) { @@ -2187,7 +2191,8 @@ TEST(detect_seccomp_filter_flags) unsigned int flags[] = { SECCOMP_FILTER_FLAG_TSYNC, SECCOMP_FILTER_FLAG_LOG, SECCOMP_FILTER_FLAG_SPEC_ALLOW, - SECCOMP_FILTER_FLAG_NEW_LISTENER }; + SECCOMP_FILTER_FLAG_NEW_LISTENER, + SECCOMP_FILTER_FLAG_TSYNC_ESRCH }; unsigned int exclusive[] = { SECCOMP_FILTER_FLAG_TSYNC, SECCOMP_FILTER_FLAG_NEW_LISTENER }; @@ -2645,6 +2650,55 @@ TEST_F(TSYNC, two_siblings_with_one_divergence) EXPECT_EQ(SIBLING_EXIT_UNKILLED, (long)status); } +TEST_F(TSYNC, two_siblings_with_one_divergence_no_tid_in_err) +{ + long ret, flags; + void *status; + + ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) { + TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); + } + + ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &self->root_prog); + ASSERT_NE(ENOSYS, errno) { + TH_LOG("Kernel does not support seccomp syscall!"); + } + ASSERT_EQ(0, ret) { + TH_LOG("Kernel does not support SECCOMP_SET_MODE_FILTER!"); + } + self->sibling[0].diverge = 1; + tsync_start_sibling(&self->sibling[0]); + tsync_start_sibling(&self->sibling[1]); + + while (self->sibling_count < TSYNC_SIBLINGS) { + sem_wait(&self->started); + self->sibling_count++; + } + + flags = SECCOMP_FILTER_FLAG_TSYNC | \ + SECCOMP_FILTER_FLAG_TSYNC_ESRCH; + ret = seccomp(SECCOMP_SET_MODE_FILTER, flags, &self->apply_prog); + ASSERT_EQ(ESRCH, errno) { + TH_LOG("Did not return ESRCH for diverged sibling."); + } + ASSERT_EQ(-1, ret) { + TH_LOG("Did not fail on diverged sibling."); + } + + /* Wake the threads */ + pthread_mutex_lock(&self->mutex); + ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) { + TH_LOG("cond broadcast non-zero"); + } + pthread_mutex_unlock(&self->mutex); + + /* Ensure they are both unkilled. */ + PTHREAD_JOIN(self->sibling[0].tid, &status); + EXPECT_EQ(SIBLING_EXIT_UNKILLED, (long)status); + PTHREAD_JOIN(self->sibling[1].tid, &status); + EXPECT_EQ(SIBLING_EXIT_UNKILLED, (long)status); +} + TEST_F(TSYNC, two_siblings_not_under_filter) { long ret, sib; @@ -3196,6 +3250,24 @@ TEST(user_notification_basic) EXPECT_EQ(0, WEXITSTATUS(status)); } +TEST(user_notification_with_tsync) +{ + int ret; + unsigned int flags; + + /* these were exclusive */ + flags = SECCOMP_FILTER_FLAG_NEW_LISTENER | + SECCOMP_FILTER_FLAG_TSYNC; + ASSERT_EQ(-1, user_trap_syscall(__NR_getppid, flags)); + ASSERT_EQ(EINVAL, errno); + + /* but now they're not */ + flags |= SECCOMP_FILTER_FLAG_TSYNC_ESRCH; + ret = user_trap_syscall(__NR_getppid, flags); + close(ret); + ASSERT_LE(0, ret); +} + TEST(user_notification_kill_in_middle) { pid_t pid; |