2023-04-14 02:37:24

by Jeff Xu

Subject: [PATCH] selftests/memfd: fix test_sysctl

From: Jeff Xu <[email protected]>

sysctl memfd_noexec is pid-namespaced, non-reservable,
and inherent to the child process.
Moving the inherence test from init ns to child ns, so
init ns can keep the default value.

Signed-off-by: Jeff Xu <[email protected]>
Reported-by: kernel test robot <[email protected]>
Link: https://lore.kernel.org/oe-lkp/[email protected]
---
tools/testing/selftests/memfd/memfd_test.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c
index ae71f15f790d..dba0e8ba002f 100644
--- a/tools/testing/selftests/memfd/memfd_test.c
+++ b/tools/testing/selftests/memfd/memfd_test.c
@@ -43,6 +43,9 @@
*/
static size_t mfd_def_size = MFD_DEF_SIZE;
static const char *memfd_str = MEMFD_STR;
+static pid_t spawn_newpid_thread(unsigned int flags, int (*fn)(void *));
+static int newpid_thread_fn2(void *arg);
+static void join_newpid_thread(pid_t pid);

static ssize_t fd2name(int fd, char *buf, size_t bufsize)
{
@@ -1111,6 +1114,7 @@ static void test_noexec_seal(void)
static void test_sysctl_child(void)
{
int fd;
+ int pid;

printf("%s sysctl 0\n", memfd_str);
sysctl_assert_write("0");
@@ -1129,6 +1133,10 @@ static void test_sysctl_child(void)
mfd_def_size,
MFD_CLOEXEC | MFD_ALLOW_SEALING);

+ printf("%s child ns\n", memfd_str);
+ pid = spawn_newpid_thread(CLONE_NEWPID, newpid_thread_fn2);
+ join_newpid_thread(pid);
+
mfd_assert_mode(fd, 0666);
mfd_assert_has_seals(fd, F_SEAL_EXEC);
mfd_fail_chmod(fd, 0777);
@@ -1206,12 +1214,6 @@ static void test_sysctl(void)
int pid = spawn_newpid_thread(CLONE_NEWPID, newpid_thread_fn);

join_newpid_thread(pid);
-
- printf("%s child ns\n", memfd_str);
- sysctl_assert_write("1");
-
- pid = spawn_newpid_thread(CLONE_NEWPID, newpid_thread_fn2);
- join_newpid_thread(pid);
}

/*
--
2.40.0.577.gac1e443424-goog

2023-04-14 06:29:21

by kernel test robot

Subject: Re: [PATCH] selftests/memfd: fix test_sysctl

On Fri, Apr 14, 2023 at 02:28:01AM +0000, [email protected] wrote:
> From: Jeff Xu <[email protected]>
>
> sysctl memfd_noexec is pid-namespaced, non-reservable,
> and inherent to the child process.
> Moving the inherence test from init ns to child ns, so
> init ns can keep the default value.
>
> Signed-off-by: Jeff Xu <[email protected]>
> Reported-by: kernel test robot <[email protected]>
> Link: https://lore.kernel.org/oe-lkp/[email protected]

The reported issue is gone after applying this patch. Thanks.

Tested-by: Yujie Liu <[email protected]>

=========================================================================================
compiler/group/kconfig/rootfs/tbox_group/testcase:
gcc-11/group-02/x86_64-rhel-8.3-kselftests/debian-12-x86_64-20220629.cgz/lkp-skl-d06/kernel-selftests

commit:
c4f75bc8bd6b3 ("mm/memfd: add write seals when apply SEAL_EXEC to executable memfd")
11f75a01448f1 ("selftests/memfd: add tests for MFD_NOEXEC_SEAL MFD_EXEC")
395874d592d77 ("selftests/memfd: fix test_sysctl")

c4f75bc8bd6b3d62 11f75a01448f1b7a739e75dbd8f 395874d592d775d999d18ef9cae
---------------- --------------------------- ---------------------------
fail:runs %reproduction fail:runs %reproduction fail:runs
| | | | |
:6 233% 14:20 0% :5 kernel-selftests.memfd.run_fuse_test.sh.fail

> ---
> tools/testing/selftests/memfd/memfd_test.c | 14 ++++++++------
> 1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c
> index ae71f15f790d..dba0e8ba002f 100644
> --- a/tools/testing/selftests/memfd/memfd_test.c
> +++ b/tools/testing/selftests/memfd/memfd_test.c
> @@ -43,6 +43,9 @@
> */
> static size_t mfd_def_size = MFD_DEF_SIZE;
> static const char *memfd_str = MEMFD_STR;
> +static pid_t spawn_newpid_thread(unsigned int flags, int (*fn)(void *));
> +static int newpid_thread_fn2(void *arg);
> +static void join_newpid_thread(pid_t pid);
>
> static ssize_t fd2name(int fd, char *buf, size_t bufsize)
> {
> @@ -1111,6 +1114,7 @@ static void test_noexec_seal(void)
> static void test_sysctl_child(void)
> {
> int fd;
> + int pid;
>
> printf("%s sysctl 0\n", memfd_str);
> sysctl_assert_write("0");
> @@ -1129,6 +1133,10 @@ static void test_sysctl_child(void)
> mfd_def_size,
> MFD_CLOEXEC | MFD_ALLOW_SEALING);
>
> + printf("%s child ns\n", memfd_str);
> + pid = spawn_newpid_thread(CLONE_NEWPID, newpid_thread_fn2);
> + join_newpid_thread(pid);
> +
> mfd_assert_mode(fd, 0666);
> mfd_assert_has_seals(fd, F_SEAL_EXEC);
> mfd_fail_chmod(fd, 0777);
> @@ -1206,12 +1214,6 @@ static void test_sysctl(void)
> int pid = spawn_newpid_thread(CLONE_NEWPID, newpid_thread_fn);
>
> join_newpid_thread(pid);
> -
> - printf("%s child ns\n", memfd_str);
> - sysctl_assert_write("1");
> -
> - pid = spawn_newpid_thread(CLONE_NEWPID, newpid_thread_fn2);
> - join_newpid_thread(pid);
> }
>
> /*
> --
> 2.40.0.577.gac1e443424-goog
>