Bug 1223767 (CVE-2024-27050)

Summary:	VUL-0: CVE-2024-27050: libbpf: use OPTS_SET() macro in bpf_xdp_query()
Product:	[Novell Products] SUSE Security Incidents	Reporter:	SMASH SMASH <smash_bz>
Component:	Incidents	Assignee:	Security Team bot <security-team>
Status:	RESOLVED UPSTREAM	QA Contact:	Security Team bot <security-team>
Severity:	Major
Priority:	P3 - Medium	CC:	camila.matos, meissner, shung-hsi.yu, vasant.karasulli
Version:	unspecified
Target Milestone:	---
Hardware:	Other
OS:	Other
URL:	https://smash.suse.de/issue/403841/
Whiteboard:	CVSSv3.1:SUSE:CVE-2024-27050:7.8:(AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
Found By:	Security Response Team	Services Priority:
Business Priority:		Blocker:	---
Marketing QA Status:	---	IT Deployment:	---

Description SMASH SMASH 2024-05-02 14:36:59 UTC

In the Linux kernel, the following vulnerability has been resolved:

libbpf: Use OPTS_SET() macro in bpf_xdp_query()

When the feature_flags and xdp_zc_max_segs fields were added to the libbpf
bpf_xdp_query_opts, the code writing them did not use the OPTS_SET() macro.
This causes libbpf to write to those fields unconditionally, which means
that programs compiled against an older version of libbpf (with a smaller
size of the bpf_xdp_query_opts struct) will have its stack corrupted by
libbpf writing out of bounds.

The patch adding the feature_flags field has an early bail out if the
feature_flags field is not part of the opts struct (via the OPTS_HAS)
macro, but the patch adding xdp_zc_max_segs does not. For consistency, this
fix just changes the assignments to both fields to use the OPTS_SET()
macro.

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2024-27050
https://www.cve.org/CVERecord?id=CVE-2024-27050
https://git.kernel.org/stable/c/682ddd62abd4bdcee7584246903e7a2df005fe0d
https://git.kernel.org/stable/c/92a871ab9fa59a74d013bc04f321026a057618e7
https://git.kernel.org/stable/c/cd3be9843247edb8fc6fcd8d8237cbce2bc19f5e
https://git.kernel.org/stable/c/fa5bef5e80c6a3321b2b1a7070436f3bc5daf07c
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2024/CVE-2024-27050.mbox
https://bugzilla.redhat.com/show_bug.cgi?id=2278427

Comment 3 Shung-Hsi Yu 2024-05-06 12:28:18 UTC

The libbpf package we provide to customer is at SUSE:SLE-15-SP6:GA/libbpf, which is sourced from the upstream repository https://github.com/libbpf/libbpf, rather  than inheriting the source from kernel-source (since SLE-15-SP4).

SUSE:SLE-15-SP6:GA/libbpf is at v1.2.2, which is roughly equivalent to v6.5 in kernel-source, and thus does not contain the buggy commit.

> $ git log -n1 --oneline --grep='Start v1.3 development' tools/lib/bpf/libbpf.map
> 2b001b94073b libbpf: Start v1.3 development cycle
> $ git describe --tags --contains 2b001b94073b
> v6.5-rc1~163^2~215^2~10

Reassigning back to security team.

Comment 4 Shung-Hsi Yu 2024-05-06 12:29:16 UTC

For completeness, this is a bug in the user-space library libbpf, and not in the Linux kernel itself.

Comment 8 Marcus Meissner 2024-05-08 13:22:02 UTC

no libbpf version affected.