ghsa-jprx-mprp-6qvx
Vulnerability from github
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] [ 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().
{
"affected": [],
"aliases": [
"CVE-2025-22070"
],
"database_specific": {
"cwe_ids": [
"CWE-476"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-04-16T15:16:01Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/9p: fix NULL pointer dereference on mkdir\n\nWhen a 9p tree was mounted with option \u0027posixacl\u0027, parent directory had a\ndefault ACL set for its subdirectories, e.g.:\n\n setfacl -m default:group:simpsons:rwx parentdir\n\nthen creating a subdirectory crashed 9p client, as v9fs_fid_add() call in\nfunction v9fs_vfs_mkdir_dotl() sets the passed \u0027fid\u0027 pointer to NULL\n(since dafbe689736) even though the subsequent v9fs_set_create_acl() call\nexpects a valid non-NULL \u0027fid\u0027 pointer:\n\n [ 37.273191] BUG: kernel NULL pointer dereference, address: 0000000000000000\n ...\n [ 37.322338] Call Trace:\n [ 37.323043] \u003cTASK\u003e\n [ 37.323621] ? __die (arch/x86/kernel/dumpstack.c:421 arch/x86/kernel/dumpstack.c:434)\n [ 37.324448] ? page_fault_oops (arch/x86/mm/fault.c:714)\n [ 37.325532] ? search_module_extables (kernel/module/main.c:3733)\n [ 37.326742] ? p9_client_walk (net/9p/client.c:1165) 9pnet\n [ 37.328006] ? search_bpf_extables (kernel/bpf/core.c:804)\n [ 37.329142] ? exc_page_fault (./arch/x86/include/asm/paravirt.h:686 arch/x86/mm/fault.c:1488 arch/x86/mm/fault.c:1538)\n [ 37.330196] ? asm_exc_page_fault (./arch/x86/include/asm/idtentry.h:574)\n [ 37.331330] ? p9_client_walk (net/9p/client.c:1165) 9pnet\n [ 37.332562] ? v9fs_fid_xattr_get (fs/9p/xattr.c:30) 9p\n [ 37.333824] v9fs_fid_xattr_set (fs/9p/fid.h:23 fs/9p/xattr.c:121) 9p\n [ 37.335077] v9fs_set_acl (fs/9p/acl.c:276) 9p\n [ 37.336112] v9fs_set_create_acl (fs/9p/acl.c:307) 9p\n [ 37.337326] v9fs_vfs_mkdir_dotl (fs/9p/vfs_inode_dotl.c:411) 9p\n [ 37.338590] vfs_mkdir (fs/namei.c:4313)\n [ 37.339535] do_mkdirat (fs/namei.c:4336)\n [ 37.340465] __x64_sys_mkdir (fs/namei.c:4354)\n [ 37.341455] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)\n [ 37.342447] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)\n\nFix this by simply swapping the sequence of these two calls in\nv9fs_vfs_mkdir_dotl(), i.e. calling v9fs_set_create_acl() before\nv9fs_fid_add().",
"id": "GHSA-jprx-mprp-6qvx",
"modified": "2025-05-06T18:30:36Z",
"published": "2025-04-16T15:34:43Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-22070"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2139dea5c53e3bb63ac49a6901c85e525a80ee8a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3f61ac7c65bdb26accb52f9db66313597e759821"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6517b395cb1e43fbf3962dd93e6fb4a5e5ab100e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8522051c58d68146b93e8a5ba9987e83b3d64e7b"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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