CVE-2022-50334
Vulnerability Summary
Timeline
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().
CVSS Metrics
- v3.1•MEDIUM•Score: 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS Trends
Current EPSS score: 0.16%• Percentile: 5%
Techniques & Countermeasures
- CWE-476•NULL Pointer Dereference
The product dereferences a pointer that it expects to be valid but is NULL.
Affected Systems
- debian•linux
< 5.10.178-1 | < 6.1.4-1 | < 6.1.4-1 | < 6.1.4-1
- ubuntu•linux
all | < 5.4.0-144.161 | < 5.15.0-69.76
- ubuntu•linux-allwinner-5.19
all
- ubuntu•linux-aws
all | < 5.4.0-1097.105 | < 5.15.0-1033.37
- ubuntu•linux-aws-5.0
all
- ubuntu•linux-aws-5.11
all
- ubuntu•linux-aws-5.13
all
- ubuntu•linux-aws-5.15
< 5.15.0-1033.37~20.04.1
- ubuntu•linux-aws-5.19
all
- ubuntu•linux-aws-5.3
all
- ubuntu•linux-aws-5.4
< 5.4.0-1097.105~18.04.1
- ubuntu•linux-aws-5.8
all
- ubuntu•linux-aws-6.2
all
- ubuntu•linux-aws-6.5
all
- ubuntu•linux-aws-fips
all | < 5.4.0-1099.107+fips1
- ubuntu•linux-aws-hwe
all
- ubuntu•linux-azure
all | all | < 5.4.0-1104.110 | < 5.15.0-1035.42
- ubuntu•linux-azure-4.15
all
- ubuntu•linux-azure-5.11
all
- ubuntu•linux-azure-5.13
all
- ubuntu•linux-azure-5.15
< 5.15.0-1035.42~20.04.1
- ubuntu•linux-azure-5.19
all
- ubuntu•linux-azure-5.3
all
- ubuntu•linux-azure-5.4
< 5.4.0-1104.110~18.04.1
- ubuntu•linux-azure-5.8
all
- ubuntu•linux-azure-6.11
all
- ubuntu•linux-azure-6.2
all
- ubuntu•linux-azure-6.5
all
- ubuntu•linux-azure-edge
all
- ubuntu•linux-azure-fde
all | all
- ubuntu•linux-azure-fde-5.15
< 5.15.0-1114.123~20.04.1
- ubuntu•linux-azure-fde-5.19
all
- ubuntu•linux-azure-fde-6.2
all
- ubuntu•linux-azure-fips
all | < 5.4.0-1104.110+fips1
- ubuntu•linux-bluefield
all | < 5.4.0-1059.65 | < 5.15.0-1015.17
- ubuntu•linux-fips
all | < 5.4.0-1073.82
- ubuntu•linux-gcp
all | all | < 5.4.0-1101.110 | < 5.15.0-1031.38
- ubuntu•linux-gcp-4.15
all
- ubuntu•linux-gcp-5.11
all
- ubuntu•linux-gcp-5.13
all
- ubuntu•linux-gcp-5.15
< 5.15.0-1031.38~20.04.1
- ubuntu•linux-gcp-5.19
all
- ubuntu•linux-gcp-5.3
all
- ubuntu•linux-gcp-5.4
< 5.4.0-1101.110~18.04.1
- ubuntu•linux-gcp-5.8
all
- ubuntu•linux-gcp-6.11
all
- ubuntu•linux-gcp-6.2
all
- ubuntu•linux-gcp-6.5
all
- ubuntu•linux-gcp-fips
all | < 5.4.0-1101.110+fips1
- ubuntu•linux-gke
all | < 5.15.0-1030.35
Showing first 50 affected entries in server-rendered view.
References (10)
- https://git.kernel.org/stable/c/fa71639873518e3587632ae58e25e4a96b57fa90
- https://git.kernel.org/stable/c/dcd28191be9bbf307ba51a5b485773a55b0037c4
- https://git.kernel.org/stable/c/9a8862820cbf1f18dca4f3b4c289d88561b3a384
- https://git.kernel.org/stable/c/965e8f8ae0f642b5528f5a82b7bcaf15a659d5bd
- https://git.kernel.org/stable/c/f2207145693ae5697a7b59e2add4b92f9e5b0e3c
- https://git.kernel.org/stable/c/26215b7ee923b9251f7bb12c4e5f09dc465d35f2
- https://ubuntu.com/security/CVE-2022-50334
- https://www.cve.org/CVERecord?id=CVE-2022-50334
- https://git.kernel.org/linus/26215b7ee923b9251f7bb12c4e5f09dc465d35f2
- https://security-tracker.debian.org/tracker/CVE-2022-50334