First published: Sun May 19 2024(Updated: )
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.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Software | Affected Version | How to fix |
---|---|---|
redhat/kernel | <5.4.274 | 5.4.274 |
redhat/kernel | <5.10.215 | 5.10.215 |
redhat/kernel | <5.15.154 | 5.15.154 |
redhat/kernel | <6.1.85 | 6.1.85 |
redhat/kernel | <6.6.26 | 6.6.26 |
redhat/kernel | <6.8.5 | 6.8.5 |
redhat/kernel | <6.9 | 6.9 |
debian/linux | 5.10.223-1 5.10.226-1 6.1.115-1 6.1.119-1 6.12.6-1 |
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