Merge branch 'bpf: fix NULL dereference during extable search'

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Krister Johansen says:

====================
Hi,
Enclosed are a pair of patches for an oops that can occur if an exception is
generated while a bpf subprogram is running.  One of the bpf_prog_aux entries
for the subprograms are missing an extable.  This can lead to an exception that
would otherwise be handled turning into a NULL pointer bug.

These changes were tested via the verifier and progs selftests and no
regressions were observed.

Changes from v4:
- Ensure that num_exentries is copied to prog->aux from func[0] (Feedback from
  Ilya Leoshkevich)

Changes from v3:
- Selftest style fixups (Feedback from Yonghong Song)
- Selftest needs to assert that test bpf program executed (Feedback from
  Yonghong Song)
- Selftest should combine open and load using open_and_load (Feedback from
  Yonghong Song)

Changes from v2:
- Insert only the main program's kallsyms (Feedback from Yonghong Song and
  Alexei Starovoitov)
- Selftest should use ASSERT instead of CHECK (Feedback from Yonghong Song)
- Selftest needs some cleanup (Feedback from Yonghong Song)
- Switch patch order (Feedback from Alexei Starovoitov)

Changes from v1:
- Add a selftest (Feedback From Alexei Starovoitov)
- Move to a 1-line verifier change instead of searching multiple extables
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

...

This commit is contained in:

Alexei Starovoitov 2023-06-13 15:13:52 -07:00

parent ad96f1c913 84a62b445c

commit b78b34c604

3 changed files with 85 additions and 2 deletions

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7

kernel/bpf/verifier.c

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29

tools/testing/selftests/bpf/prog_tests/subprogs_extable.c

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51

tools/testing/selftests/bpf/progs/test_subprogs_extable.c

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