Description
In the Linux kernel, the following vulnerability has been resolved: hugetlbfs: fix null-ptr-deref in hugetlbfs_parse_param() Syzkaller reports a null-ptr-deref bug as follows: ====================================================== KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: 0010:hugetlbfs_parse_param+0x1dd/0x8e0 fs/hugetlbfs/inode.c:1380 [...] Call Trace: <TASK> vfs_parse_fs_param fs/fs_context.c:148 [inline] vfs_parse_fs_param+0x1f9/0x3c0 fs/fs_context.c:129 vfs_parse_fs_string+0xdb/0x170 fs/fs_context.c:191 generic_parse_monolithic+0x16f/0x1f0 fs/fs_context.c:231 do_new_mount fs/namespace.c:3036 [inline] path_mount+0x12de/0x1e20 fs/namespace.c:3370 do_mount fs/namespace.c:3383 [inline] __do_sys_mount fs/namespace.c:3591 [inline] __se_sys_mount fs/namespace.c:3568 [inline] __x64_sys_mount+0x27f/0x300 fs/namespace.c:3568 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd [...] </TASK> ====================================================== According to commit "vfs: parse: deal with zero length string value", kernel will set the param->string to null pointer in vfs_parse_fs_string() if fs string has zero length. Yet the problem is that, hugetlbfs_parse_param() will dereference the param->string, without checking whether it is a null pointer. To be more specific, if hugetlbfs_parse_param() parses an illegal mount parameter, such as "size=,", kernel will constructs struct fs_parameter with null pointer in vfs_parse_fs_string(), then passes this struct fs_parameter to hugetlbfs_parse_param(), which triggers the above null-ptr-deref bug. This patch solves it by adding sanity check on param->string in hugetlbfs_parse_param().
Product status
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before fa71639873518e3587632ae58e25e4a96b57fa90
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before dcd28191be9bbf307ba51a5b485773a55b0037c4
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before 9a8862820cbf1f18dca4f3b4c289d88561b3a384
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before 965e8f8ae0f642b5528f5a82b7bcaf15a659d5bd
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before f2207145693ae5697a7b59e2add4b92f9e5b0e3c
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before 26215b7ee923b9251f7bb12c4e5f09dc465d35f2
5.4.229 (semver)
5.10.163 (semver)
5.15.86 (semver)
6.0.16 (semver)
6.1.2 (semver)
6.2 (original_commit_for_fix)
References
git.kernel.org/...c/fa71639873518e3587632ae58e25e4a96b57fa90
git.kernel.org/...c/dcd28191be9bbf307ba51a5b485773a55b0037c4
git.kernel.org/...c/9a8862820cbf1f18dca4f3b4c289d88561b3a384
git.kernel.org/...c/965e8f8ae0f642b5528f5a82b7bcaf15a659d5bd
git.kernel.org/...c/f2207145693ae5697a7b59e2add4b92f9e5b0e3c
git.kernel.org/...c/26215b7ee923b9251f7bb12c4e5f09dc465d35f2
