ghsa-p2qw-28x5-q4gw
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_tables: unlink table before deleting it
syzbot reports following UAF: BUG: KASAN: use-after-free in memcmp+0x18f/0x1c0 lib/string.c:955 nla_strcmp+0xf2/0x130 lib/nlattr.c:836 nft_table_lookup.part.0+0x1a2/0x460 net/netfilter/nf_tables_api.c:570 nft_table_lookup net/netfilter/nf_tables_api.c:4064 [inline] nf_tables_getset+0x1b3/0x860 net/netfilter/nf_tables_api.c:4064 nfnetlink_rcv_msg+0x659/0x13f0 net/netfilter/nfnetlink.c:285 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504
Problem is that all get operations are lockless, so the commit_mutex held by nft_rcv_nl_event() isn't enough to stop a parallel GET request from doing read-accesses to the table object even after synchronize_rcu().
To avoid this, unlink the table first and store the table objects in on-stack scratch space.
{
"affected": [],
"aliases": [
"CVE-2021-47394"
],
"database_specific": {
"cwe_ids": [
"CWE-416"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-05-21T15:15:24Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_tables: unlink table before deleting it\n\nsyzbot reports following UAF:\nBUG: KASAN: use-after-free in memcmp+0x18f/0x1c0 lib/string.c:955\n nla_strcmp+0xf2/0x130 lib/nlattr.c:836\n nft_table_lookup.part.0+0x1a2/0x460 net/netfilter/nf_tables_api.c:570\n nft_table_lookup net/netfilter/nf_tables_api.c:4064 [inline]\n nf_tables_getset+0x1b3/0x860 net/netfilter/nf_tables_api.c:4064\n nfnetlink_rcv_msg+0x659/0x13f0 net/netfilter/nfnetlink.c:285\n netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504\n\nProblem is that all get operations are lockless, so the commit_mutex\nheld by nft_rcv_nl_event() isn\u0027t enough to stop a parallel GET request\nfrom doing read-accesses to the table object even after synchronize_rcu().\n\nTo avoid this, unlink the table first and store the table objects in\non-stack scratch space.",
"id": "GHSA-p2qw-28x5-q4gw",
"modified": "2025-02-03T18:30:37Z",
"published": "2024-05-21T15:31:44Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-47394"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a499b03bf36b0c2e3b958a381d828678ab0ffc5e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f65c73d3aabb87d4353e0bc4a718b5ae8c43fd04"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.