CVE-2024-56665

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> bpf,perf: Fix invalid prog_array access in perf_event_detach_bpf_prog<br /> <br /> Syzbot reported [1] crash that happens for following tracing scenario:<br /> <br /> - create tracepoint perf event with attr.inherit=1, attach it to the<br /> process and set bpf program to it<br /> - attached process forks -&gt; chid creates inherited event<br /> <br /> the new child event shares the parent&amp;#39;s bpf program and tp_event<br /> (hence prog_array) which is global for tracepoint<br /> <br /> - exit both process and its child -&gt; release both events<br /> - first perf_event_detach_bpf_prog call will release tp_event-&gt;prog_array<br /> and second perf_event_detach_bpf_prog will crash, because<br /> tp_event-&gt;prog_array is NULL<br /> <br /> The fix makes sure the perf_event_detach_bpf_prog checks prog_array<br /> is valid before it tries to remove the bpf program from it.<br /> <br /> [1] https://lore.kernel.org/bpf/Z1MR6dCIKajNS6nU@krava/T/#m91dbf0688221ec7a7fc95e896a7ef9ff93b0b8ad