From a402f1e35313fc7ce2ca60f543c4402c2c7c3544 Mon Sep 17 00:00:00 2001 From: Tobias Klauser Date: Wed, 8 Mar 2023 11:51:26 +0100 Subject: [PATCH 1/2] fork: allow CLONE_NEWTIME in clone3 flags Currently, calling clone3() with CLONE_NEWTIME in clone_args->flags fails with -EINVAL. This is because CLONE_NEWTIME intersects with CSIGNAL. However, CSIGNAL was deprecated when clone3 was introduced in commit 7f192e3cd316 ("fork: add clone3"), allowing re-use of that part of clone flags. Fix this by explicitly allowing CLONE_NEWTIME in clone3_args_valid. This is also in line with the respective check in check_unshare_flags which allow CLONE_NEWTIME for unshare(). Fixes: 769071ac9f20 ("ns: Introduce Time Namespace") Cc: Andrey Vagin Cc: Christian Brauner Cc: stable@vger.kernel.org Signed-off-by: Tobias Klauser Reviewed-by: Christian Brauner Signed-off-by: Christian Brauner (Microsoft) --- kernel/fork.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/fork.c b/kernel/fork.c index f68954d05e89..d8cda4c6de6c 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2936,7 +2936,7 @@ static bool clone3_args_valid(struct kernel_clone_args *kargs) * - make the CLONE_DETACHED bit reusable for clone3 * - make the CSIGNAL bits reusable for clone3 */ - if (kargs->flags & (CLONE_DETACHED | CSIGNAL)) + if (kargs->flags & (CLONE_DETACHED | (CSIGNAL & (~CLONE_NEWTIME)))) return false; if ((kargs->flags & (CLONE_SIGHAND | CLONE_CLEAR_SIGHAND)) == From 515bddf0ec4155cbd666d72daf5bd68c8b7cd987 Mon Sep 17 00:00:00 2001 From: Tobias Klauser Date: Wed, 8 Mar 2023 11:53:20 +0100 Subject: [PATCH 2/2] selftests/clone3: test clone3 with CLONE_NEWTIME Verify that clone3 can be called successfully with CLONE_NEWTIME in flags. Cc: Andrey Vagin Cc: Christian Brauner Cc: Shuah Khan Signed-off-by: Tobias Klauser Signed-off-by: Christian Brauner (Microsoft) --- tools/testing/selftests/clone3/clone3.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tools/testing/selftests/clone3/clone3.c b/tools/testing/selftests/clone3/clone3.c index cd4582129c7d..4fce46afe6db 100644 --- a/tools/testing/selftests/clone3/clone3.c +++ b/tools/testing/selftests/clone3/clone3.c @@ -195,5 +195,8 @@ int main(int argc, char *argv[]) test_clone3(CLONE_NEWPID, getpagesize() + 8, -E2BIG, CLONE3_ARGS_NO_TEST); + /* Do a clone3() in a new time namespace */ + test_clone3(CLONE_NEWTIME, 0, 0, CLONE3_ARGS_NO_TEST); + return !ksft_get_fail_cnt() ? ksft_exit_pass() : ksft_exit_fail(); }