Linux vulnerability

What happened

In the Linux kernel, the following vulnerability has been resolved: bpf: Mark signal tracepoint siginfo arguments as scalar The signal_generate and signal_deliver tracepoints declare their info argument as a struct kernel_siginfo pointer. btf_ctx_access() therefore treats it as a trusted pointer for tp_btf programs. Signal delivery also uses SEND_SIG_NOINFO and SEND_SIG_PRIV as special values for this argument. Those values are zero and one respectively, and are not pointers. A tp_btf program can currently dereference either value and fault the kernel. In particular, signal_generate can run from timer interrupt context, turning the fault into a kernel panic. Record both tracepoints in raw_tp_null_args[] and mark argument one as a non-pointer. This preserves scalar access to the cookie while rejecting direct and helper-mediated pointer use. Merely marking it nullable would not suffice because SEND_SIG_PRIV is nonzero.

Affected versions

Linux: 838a10bd2ebfe11a60dd67687533a7cfc220cc86 through before 0e78cb242a57e481061fcb542fed4d51afba25c4 (git); 838a10bd2ebfe11a60dd67687533a7cfc220cc86 through before d2eaea3599bcce659ce91862254dc91bcbdb6351 (git); 838a10bd2ebfe11a60dd67687533a7cfc220cc86 through before 77515ab12e4983e6416f8c35039a3f0c0822ac70 (git); b2fc4b17fc13810ef440fb323fad3981cd174985 (git); 6.12.6 through before 6.13 (semver); 6.13 Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

• Apply vendor-provided updates or mitigations.
• Review affected product exposure and access logs.