Bug 2297580 (CVE-2024-40996) - CVE-2024-40996 kernel: bpf: Avoid splat in pskb_pull_reason
Summary: CVE-2024-40996 kernel: bpf: Avoid splat in pskb_pull_reason
Keywords:
Status: NEW
Alias: CVE-2024-40996
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
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Blocks:
TreeView+ depends on / blocked
 
Reported: 2024-07-12 13:48 UTC by OSIDB Bzimport
Modified: 2024-09-24 14:00 UTC (History)
4 users (show)

Fixed In Version: kernel 6.1.96, kernel 6.6.36, kernel 6.9.7, kernel 6.10-rc5
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Doc Text:
A vulnerability found in the Linux kernel’s bpf subsystem, involving a frequent warning (splat) in pskb_may_pull during syzkaller builds (CONFIG_DEBUG_NET=y), has been resolved. The warning, caused by nonsensical BPF programs generated by fuzzers, was suppressed as it provided no useful information. For non-debug builds (CONFIG_DEBUG_NET=n), the check is unnecessary, as pskb_may_pull handles errors without triggering warnings.
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Description OSIDB Bzimport 2024-07-12 13:48:51 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.
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