CVE-2024-35895

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.

• linux linux kernel (>= 4.20 < 5.4.274) • linux linux kernel (>= 5.5 < 5.10.215) • linux linux kernel (>= 5.11 < 5.15.154) • linux linux kernel (>= 5.16 < 6.1.85) • linux linux kernel (>= 6.2 < 6.6.26) • linux linux kernel (>= 6.7 < 6.8.5) • linux linux kernel 6.9 • debian debian linux 10.0