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| author | Roberto Sassu <roberto.sassu@huawei.com> | 2023-06-07 15:24:27 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-06-19 13:19:31 -0700 |
| commit | 935d44acf621aa0688fef8312dec3e5940f38f4e (patch) | |
| tree | eef706b0b5d6eb69ca354954d96c52119c34d232 /mm | |
| parent | 95a301eefa82057571207edd06ea36218985a75e (diff) | |
| download | linux-935d44acf621aa0688fef8312dec3e5940f38f4e.tar.gz linux-935d44acf621aa0688fef8312dec3e5940f38f4e.tar.bz2 linux-935d44acf621aa0688fef8312dec3e5940f38f4e.zip | |
memfd: check for non-NULL file_seals in memfd_create() syscall
Ensure that file_seals is non-NULL before using it in the memfd_create()
syscall. One situation in which memfd_file_seals_ptr() could return a
NULL pointer when CONFIG_SHMEM=n, oopsing the kernel.
Link: https://lkml.kernel.org/r/20230607132427.2867435-1-roberto.sassu@huaweicloud.com
Fixes: 47b9012ecdc7 ("shmem: add sealing support to hugetlb-backed memfd")
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Cc: Marc-Andr Lureau <marcandre.lureau@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/memfd.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/mm/memfd.c b/mm/memfd.c index 69b90c31d38c..e763e76f1106 100644 --- a/mm/memfd.c +++ b/mm/memfd.c @@ -371,12 +371,15 @@ SYSCALL_DEFINE2(memfd_create, inode->i_mode &= ~0111; file_seals = memfd_file_seals_ptr(file); - *file_seals &= ~F_SEAL_SEAL; - *file_seals |= F_SEAL_EXEC; + if (file_seals) { + *file_seals &= ~F_SEAL_SEAL; + *file_seals |= F_SEAL_EXEC; + } } else if (flags & MFD_ALLOW_SEALING) { /* MFD_EXEC and MFD_ALLOW_SEALING are set */ file_seals = memfd_file_seals_ptr(file); - *file_seals &= ~F_SEAL_SEAL; + if (file_seals) + *file_seals &= ~F_SEAL_SEAL; } fd_install(fd, file); |