CVE-2024-35895

Published: 19 May 2024

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.

Status

References

• https://www.cve.org/CVERecord?id=CVE-2024-35895
• https://git.kernel.org/linus/ff91059932401894e6c86341915615c5eb0eca48 (6.9-rc3)
• https://git.kernel.org/stable/c/f7990498b05ac41f7d6a190dc0418ef1d21bf058
• https://git.kernel.org/stable/c/dd54b48db0c822ae7b520bc80751f0a0a173ef75
• https://git.kernel.org/stable/c/d1e73fb19a4c872d7a399ad3c66e8ca30e0875ec
• https://git.kernel.org/stable/c/a44770fed86515eedb5a7c00b787f847ebb134a5
• https://git.kernel.org/stable/c/668b3074aa14829e2ac2759799537a93b60fef86
• https://git.kernel.org/stable/c/6af057ccdd8e7619960aca1f0428339f213b31cd
• https://git.kernel.org/stable/c/ff91059932401894e6c86341915615c5eb0eca48
• https://ubuntu.com/security/notices/USN-6893-1
• https://ubuntu.com/security/notices/USN-6896-1
• https://ubuntu.com/security/notices/USN-6898-1
• https://ubuntu.com/security/notices/USN-6893-2
• https://ubuntu.com/security/notices/USN-6896-2
• https://ubuntu.com/security/notices/USN-6898-2
• https://ubuntu.com/security/notices/USN-6896-3
• https://ubuntu.com/security/notices/USN-6898-3
• https://ubuntu.com/security/notices/USN-6896-4
• https://ubuntu.com/security/notices/USN-6896-5
• https://ubuntu.com/security/notices/USN-6893-3
• https://ubuntu.com/security/notices/USN-6898-4
• https://ubuntu.com/security/notices/USN-6917-1
• https://ubuntu.com/security/notices/USN-6919-1
• https://ubuntu.com/security/notices/USN-6918-1
• https://ubuntu.com/security/notices/USN-6927-1
• NVD
• Launchpad
• Debian