UBUNTU-CVE-2025-22070
In the Linux kernel, the following vulnerability has been resolved: fs/9p: fix NULL pointer dereference on mkdir When a 9p tree was mounted with option 'posixacl', parent directory had a default ACL set for its subdirectories, e.g.: setfacl -m default:group:simpsons:rwx parentdir then creating a subdirectory crashed 9p client, as v9fs_fid_add() call in function v9fs_vfs_mkdir_dotl() sets the passed 'fid' pointer to NULL (since dafbe689736) even though the subsequent v9fs_set_create_acl() call expects a valid non-NULL 'fid' pointer: [ 37.273191] BUG: kernel NULL pointer dereference, address: 0000000000000000 ... [ 37.322338] Call Trace: [ 37.323043] <TASK> [ 37.323621] ? __die (arch/x86/kernel/dumpstack.c:421 arch/x86/kernel/dumpstack.c:434) [ 37.324448] ? page_fault_oops (arch/x86/mm/fault.c:714) [ 37.325532] ? search_module_extables (kernel/module/main.c:3733) [ 37.326742] ? p9_client_walk (net/9p/client.c:1165) 9pnet [ 37.328006] ? search_bpf_extables (kernel/bpf/core.c:804) [ 37.329142] ? exc_page_fault (./arch/x86/include/asm/paravirt.h:686 arch/x86/mm/fault.c:1488 arch/x86/mm/fault.c:1538) [ 37.330196] ? asm_exc_page_fault (./arch/x86/include/asm/idtentry.h:574) [ 37.331330] ? p9_client_walk (net/9p/client.c:1165) 9pnet [ 37.332562] ? v9fs_fid_xattr_get (fs/9p/xattr.c:30) 9p [ 37.333824] v9fs_fid_xattr_set (fs/9p/fid.h:23 fs/9p/xattr.c:121) 9p [ 37.335077] v9fs_set_acl (fs/9p/acl.c:276) 9p [ 37.336112] v9fs_set_create_acl (fs/9p/acl.c:307) 9p [ 37.337326] v9fs_vfs_mkdir_dotl (fs/9p/vfs_inode_dotl.c:411) 9p [ 37.338590] vfs_mkdir (fs/namei.c:4313) [ 37.339535] do_mkdirat (fs/namei.c:4336) [ 37.340465] __x64_sys_mkdir (fs/namei.c:4354) [ 37.341455] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) [ 37.342447] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) Fix this by simply swapping the sequence of these two calls in v9fs_vfs_mkdir_dotl(), i.e. calling v9fs_set_create_acl() before v9fs_fid_add().
02 / AFFECTED SOFTWARE
Affected packages
11 explicit affected versions
50 explicit affected versions
6 explicit affected versions
12 explicit affected versions
19 explicit affected versions
6 explicit affected versions
24 explicit affected versions
10 explicit affected versions
23 explicit affected versions
26 explicit affected versions
7 explicit affected versions
27 explicit affected versions
13 explicit affected versions
30 explicit affected versions
35 explicit affected versions
18 explicit affected versions
32 explicit affected versions
13 explicit affected versions
4 explicit affected versions
23 explicit affected versions
38 explicit affected versions
1 explicit affected versions
21 explicit affected versions
16 explicit affected versions
10 explicit affected versions
34 explicit affected versions
6 explicit affected versions
7 explicit affected versions
12 explicit affected versions
6 explicit affected versions
12 explicit affected versions
14 explicit affected versions
10 explicit affected versions
1 explicit affected versions
7 explicit affected versions
5 explicit affected versions
12 explicit affected versions
12 explicit affected versions
27 explicit affected versions
21 explicit affected versions
20 explicit affected versions
10 explicit affected versions
37 explicit affected versions
8 explicit affected versions
13 explicit affected versions
26 explicit affected versions
10 explicit affected versions
26 explicit affected versions
2 explicit affected versions
13 explicit affected versions
29 explicit affected versions
13 explicit affected versions
27 explicit affected versions
27 explicit affected versions
33 explicit affected versions
23 explicit affected versions
10 explicit affected versions
6 explicit affected versions
5 explicit affected versions
11 explicit affected versions
12 explicit affected versions
7 explicit affected versions
12 explicit affected versions
10 explicit affected versions
26 explicit affected versions
28 explicit affected versions
21 explicit affected versions
33 explicit affected versions
13 explicit affected versions
32 explicit affected versions
16 explicit affected versions
36 explicit affected versions
3 explicit affected versions
5 explicit affected versions
51 explicit affected versions
15 explicit affected versions
28 explicit affected versions
12 explicit affected versions
27 explicit affected versions
29 explicit affected versions
8 explicit affected versions
5 explicit affected versions
3 explicit affected versions
8 explicit affected versions
10 explicit affected versions
5 explicit affected versions
32 explicit affected versions
13 explicit affected versions
13 explicit affected versions
7 explicit affected versions
5 explicit affected versions
10 explicit affected versions
12 explicit affected versions
44 explicit affected versions
16 explicit affected versions
3 explicit affected versions
13 explicit affected versions
26 explicit affected versions
45 explicit affected versions
37 explicit affected versions
37 explicit affected versions
14 explicit affected versions
38 explicit affected versions
9 explicit affected versions
11 explicit affected versions
25 explicit affected versions
8 explicit affected versions
7 explicit affected versions
4 explicit affected versions
1 explicit affected versions
13 explicit affected versions
43 explicit affected versions
10 explicit affected versions
8 explicit affected versions
31 explicit affected versions
14 explicit affected versions
4 explicit affected versions
78 explicit affected versions
11 explicit affected versions
1 explicit affected versions
5 explicit affected versions
25 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: fs/9p: fix NULL pointer dereference on mkdir When a 9p tree was mounted with option 'posixacl', parent directory had a default ACL set for its subdirectories, e.g.: setfacl -m default:group:simpsons:rwx parentdir then creating a subdirectory crashed 9p client, as v9fs_fid_add() call in function v9fs_vfs_mkdir_dotl() sets the passed 'fid' pointer to NULL (since dafbe689736) even though the subsequent v9fs_set_create_acl() call expects a valid non-NULL 'fid' pointer: [ 37.273191] BUG: kernel NULL pointer dereference, address: 0000000000000000 ... [ 37.322338] Call Trace: [ 37.323043] <TASK> [ 37.323621] ? __die (arch/x86/kernel/dumpstack.c:421 arch/x86/kernel/dumpstack.c:434) [ 37.324448] ? page_fault_oops (arch/x86/mm/fault.c:714) [ 37.325532] ? search_module_extables (kernel/module/main.c:3733) [ 37.326742] ? p9_client_walk (net/9p/client.c:1165) 9pnet [ 37.328006] ? search_bpf_extables (kernel/bpf/core.c:804) [ 37.329142] ? exc_page_fault (./arch/x86/include/asm/paravirt.h:686 arch/x86/mm/fault.c:1488 arch/x86/mm/fault.c:1538) [ 37.330196] ? asm_exc_page_fault (./arch/x86/include/asm/idtentry.h:574) [ 37.331330] ? p9_client_walk (net/9p/client.c:1165) 9pnet [ 37.332562] ? v9fs_fid_xattr_get (fs/9p/xattr.c:30) 9p [ 37.333824] v9fs_fid_xattr_set (fs/9p/fid.h:23 fs/9p/xattr.c:121) 9p [ 37.335077] v9fs_set_acl (fs/9p/acl.c:276) 9p [ 37.336112] v9fs_set_create_acl (fs/9p/acl.c:307) 9p [ 37.337326] v9fs_vfs_mkdir_dotl (fs/9p/vfs_inode_dotl.c:411) 9p [ 37.338590] vfs_mkdir (fs/namei.c:4313) [ 37.339535] do_mkdirat (fs/namei.c:4336) [ 37.340465] __x64_sys_mkdir (fs/namei.c:4354) [ 37.341455] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) [ 37.342447] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) Fix this by simply swapping the sequence of these two calls in v9fs_vfs_mkdir_dotl(), i.e. calling v9fs_set_create_acl() before v9fs_fid_add().
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/3f61ac7c65bdb26accb52f9db66313597e759821
- https://git.kernel.org/stable/c/2139dea5c53e3bb63ac49a6901c85e525a80ee8a
- https://git.kernel.org/stable/c/3f61ac7c65bdb26accb52f9db66313597e759821
- https://git.kernel.org/stable/c/6517b395cb1e43fbf3962dd93e6fb4a5e5ab100e
- https://git.kernel.org/stable/c/8522051c58d68146b93e8a5ba9987e83b3d64e7b
- https://ubuntu.com/security/CVE-2025-22070
- https://ubuntu.com/security/notices/USN-7594-1
- https://ubuntu.com/security/notices/USN-7594-2
- https://ubuntu.com/security/notices/USN-7594-3
- https://ubuntu.com/security/notices/USN-7605-1
- https://ubuntu.com/security/notices/USN-7605-2
- https://ubuntu.com/security/notices/USN-7606-1
- https://ubuntu.com/security/notices/USN-7628-1
- https://ubuntu.com/security/notices/USN-7835-1
- https://ubuntu.com/security/notices/USN-7835-2
- https://ubuntu.com/security/notices/USN-7835-3
- https://ubuntu.com/security/notices/USN-7835-4
- https://ubuntu.com/security/notices/USN-7835-5
- https://ubuntu.com/security/notices/USN-7835-6
- https://ubuntu.com/security/notices/USN-7887-1
- https://ubuntu.com/security/notices/USN-7887-2
- https://ubuntu.com/security/notices/USN-7940-1
- https://ubuntu.com/security/notices/USN-7940-2
- https://www.cve.org/CVERecord?id=CVE-2025-22070