CVE-2024-35895

Summary

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

bpf, sockmap: Prevent lock inversion deadlock in map delete elem

syzkaller started using corpuses where a BPF tracing program deletes elements from a sockmap/sockhash map. Because BPF tracing programs can be invoked from any interrupt context, locks taken during a map_delete_elem operation must be hardirq-safe. Otherwise a deadlock due to lock inversion is possible, as reported by lockdep:

   CPU0                    CPU1
   ----                    ----

lock(&htab->buckets[i].lock); local_irq_disable(); lock(&host->lock); lock(&htab->buckets[i].lock); <Interrupt> lock(&host->lock);

Locks in sockmap are hardirq-unsafe by design. We expects elements to be deleted from sockmap/sockhash only in task (normal) context with interrupts enabled, or in softirq context.

Detect when map_delete_elem operation is invoked from a context which is not hardirq-unsafe, that is interrupts are disabled, and bail out with an error.

Note that map updates are not affected by this issue. BPF verifier does not allow updating sockmap/sockhash from a BPF tracing program today.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux604326b41a6fb9b4a78b6179335decee0365cd8c < f7990498b05ac41f7d6a190dc0418ef1d21bf058affected
LinuxLinux604326b41a6fb9b4a78b6179335decee0365cd8c < dd54b48db0c822ae7b520bc80751f0a0a173ef75affected
LinuxLinux604326b41a6fb9b4a78b6179335decee0365cd8c < d1e73fb19a4c872d7a399ad3c66e8ca30e0875ecaffected
LinuxLinux604326b41a6fb9b4a78b6179335decee0365cd8c < a44770fed86515eedb5a7c00b787f847ebb134a5affected
LinuxLinux604326b41a6fb9b4a78b6179335decee0365cd8c < 668b3074aa14829e2ac2759799537a93b60fef86affected
LinuxLinux604326b41a6fb9b4a78b6179335decee0365cd8c < 6af057ccdd8e7619960aca1f0428339f213b31cdaffected
LinuxLinux604326b41a6fb9b4a78b6179335decee0365cd8c < ff91059932401894e6c86341915615c5eb0eca48affected
LinuxLinux4.20affected
LinuxLinux0 < 4.20unaffected
LinuxLinux5.4.274 <= 5.4.*unaffected
LinuxLinux5.10.215 <= 5.10.*unaffected
LinuxLinux5.15.154 <= 5.15.*unaffected
LinuxLinux6.1.85 <= 6.1.*unaffected
LinuxLinux6.6.26 <= 6.6.*unaffected
LinuxLinux6.8.5 <= 6.8.*unaffected
LinuxLinux6.9 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

CVE Program Container

Additional References

Additional References

References