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authorLinus Torvalds <torvalds@linux-foundation.org>2020-03-30 12:53:56 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-03-30 12:53:56 -0700
commit78b0dedd529239332b1f8c24dfc9e6c1c322880e (patch)
tree95255b091f2c97c1f3077fa27db394dde9451632
parent377ad0c28c1df7b0634e697f34bdea8325f39a66 (diff)
parent3db81afd99494a33f1c3839103f0429c8f30cb9d (diff)
downloadlinux-78b0dedd529239332b1f8c24dfc9e6c1c322880e.tar.bz2
Merge tag 'seccomp-v5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull seccomp updates from Kees Cook: "A couple of seccomp updates. They're both mostly bug fixes that I wanted to have sit in linux-next for a while: - allow TSYNC and USER_NOTIF together (Tycho Andersen) - add missing compat_ioctl for notify (Sven Schnelle)" * tag 'seccomp-v5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: seccomp: Add missing compat_ioctl for notify seccomp: allow TSYNC and USER_NOTIF together
-rw-r--r--include/linux/seccomp.h3
-rw-r--r--include/uapi/linux/seccomp.h1
-rw-r--r--kernel/seccomp.c15
-rw-r--r--tools/testing/selftests/seccomp/seccomp_bpf.c74
4 files changed, 87 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..ec5c606bc3a1 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. */
@@ -1221,6 +1225,7 @@ static const struct file_operations seccomp_notify_ops = {
.poll = seccomp_notify_poll,
.release = seccomp_notify_release,
.unlocked_ioctl = seccomp_notify_ioctl,
+ .compat_ioctl = seccomp_notify_ioctl,
};
static struct file *init_listener(struct seccomp_filter *filter)
@@ -1288,10 +1293,12 @@ 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;