CVE-2021-47394

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.

CVSS v3 7.8 HIGH

7.8^/10

CVSS v3 : HIGH

Vector :

Exploitability : 1.8 / Impact : 5.9

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://git.kernel.org/stable/c/a499b03bf36b0c2e3b958a381d828678ab0ffc5e	Patch
https://git.kernel.org/stable/c/f65c73d3aabb87d4353e0bc4a718b5ae8c43fd04	Patch
https://git.kernel.org/stable/c/a499b03bf36b0c2e3b958a381d828678ab0ffc5e	Patch
https://git.kernel.org/stable/c/f65c73d3aabb87d4353e0bc4a718b5ae8c43fd04	Patch

Configurations

Configuration 1 (hide)

OR	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel:5.15:rc1::::::
	cpe:2.3:o:linux:linux_kernel:5.15:rc2::::::
	cpe:2.3:o:linux:linux_kernel:5.15:rc3::::::

History

No history.

Information

Published : 2024-05-21 15:15

Updated : 2025-02-03 16:11

NVD link : CVE-2021-47394

Mitre link : CVE-2021-47394

CVE.ORG link : CVE-2021-47394

JSON object : View

Products Affected

linux

linux_kernel

CWE

CWE-416

Use After Free

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