Bug 1227831 (CVE-2024-40996)

Summary:	VUL-0: CVE-2024-40996: kernel: bpf: Avoid splat in pskb_pull_reason
Product:	[Novell Products] SUSE Security Incidents	Reporter:	SMASH SMASH <smash_bz>
Component:	Incidents	Assignee:	Security Team bot <security-team>
Status:	RESOLVED FIXED	QA Contact:	Security Team bot <security-team>
Severity:	Normal
Priority:	P3 - Medium	CC:	gianluca.gabrielli, miroslav.franc
Version:	unspecified
Target Milestone:	---
Hardware:	Other
OS:	Other
URL:	https://smash.suse.de/issue/413923/
Whiteboard:
Found By:	Security Response Team	Services Priority:
Business Priority:		Blocker:	---
Marketing QA Status:	---	IT Deployment:	---

Description SMASH SMASH 2024-07-15 13:38:27 UTC

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

bpf: Avoid splat in pskb_pull_reason

syzkaller builds (CONFIG_DEBUG_NET=y) frequently trigger a debug
hint in pskb_may_pull.

We'd like to retain this debug check because it might hint at integer
overflows and other issues (kernel code should pull headers, not huge
value).

In bpf case, this splat isn't interesting at all: such (nonsensical)
bpf programs are typically generated by a fuzzer anyway.

Do what Eric suggested and suppress such warning.

For CONFIG_DEBUG_NET=n we don't need the extra check because
pskb_may_pull will do the right thing: return an error without the
WARN() backtrace.

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2024-40996
https://www.cve.org/CVERecord?id=CVE-2024-40996
https://git.kernel.org/stable/c/2bbe3e5a2f4ef69d13be54f1cf895b4658287080
https://git.kernel.org/stable/c/5e90258303a358e88737afb5048bee9113beea3a
https://git.kernel.org/stable/c/7f9644782c559635bd676c12c59389a34ed7c866
https://git.kernel.org/stable/c/dacc15e9cb248d19e5fc63c54bef0b9b55007761
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2024/CVE-2024-40996.mbox

Comment 4 Andrea Mattiazzo 2024-07-19 12:38:59 UTC

All done, closing.