Bug 2334534 (CVE-2024-56665)

Summary: CVE-2024-56665 kernel: bpf,perf: Fix invalid prog_array access in perf_event_detach_bpf_prog
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2024-12-27 16:01:54 UTC
In the Linux kernel, the following vulnerability has been resolved:

bpf,perf: Fix invalid prog_array access in perf_event_detach_bpf_prog

Syzbot reported [1] crash that happens for following tracing scenario:

  - create tracepoint perf event with attr.inherit=1, attach it to the
    process and set bpf program to it
  - attached process forks -> chid creates inherited event

    the new child event shares the parent's bpf program and tp_event
    (hence prog_array) which is global for tracepoint

  - exit both process and its child -> release both events
  - first perf_event_detach_bpf_prog call will release tp_event->prog_array
    and second perf_event_detach_bpf_prog will crash, because
    tp_event->prog_array is NULL

The fix makes sure the perf_event_detach_bpf_prog checks prog_array
is valid before it tries to remove the bpf program from it.

[1] https://lore.kernel.org/bpf/Z1MR6dCIKajNS6nU@krava/T/#m91dbf0688221ec7a7fc95e896a7ef9ff93b0b8ad

Comment 1 Avinash Hanwate 2024-12-28 03:31:19 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024122753-CVE-2024-56665-5df3@gregkh/T