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bpf, sockmap: Prevent lock inversion deadlock in map delete elem
stable inclusion from stable-v5.10.215 commit dd54b48db0c822ae7b520bc80751f0a0a173ef75 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9QG7M CVE: CVE-2024-35895 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=dd54b48db0c822ae7b520bc80751f0a0a173ef75 --------------------------- commit ff91059932401894e6c86341915615c5eb0eca48 upstream. 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. Fixes: 604326b4 ("bpf, sockmap: convert to generic sk_msg interface") Reported-by:xingwei lee <xrivendell7@gmail.com> Reported-by: