From: Kui-Feng Lee <thinker.li@xxxxxxxxx> Recently, cfi_stubs were introduced. However, existing struct_ops types that are not in the upstream may not be aware of this, resulting in kernel crashes. By rejecting struct_ops types that do not provide cfi_stubs properly during registration, these crashes can be avoided. --- Changes from v3: - Remove CFI stub function for get_info. - Allow passing NULL prog arg to check_member of struct bpf_struct_ops type. - Call check_member to determines if a CFI stub function should be defined for an operator. Changes from v2: - Add a stub function for get_info of struct tcp_congestion_ops. Changes from v1: - Check *(void **)(cfi_stubs + moff) to make sure stub functions are provided for every operator. - Add a test case to ensure that struct_ops rejects incomplete cfi_stub. v3: https://lore.kernel.org/all/20240216193434.735874-1-thinker.li@xxxxxxxxx/ v2: https://lore.kernel.org/all/20240216020350.2061373-1-thinker.li@xxxxxxxxx/ v1: https://lore.kernel.org/all/20240215022401.1882010-1-thinker.li@xxxxxxxxx/ Kui-Feng Lee (3): bpf, net: allow passing NULL prog to check_member. bpf: Check cfi_stubs before registering a struct_ops type. selftests/bpf: Test case for lacking CFI stub functions. kernel/bpf/bpf_struct_ops.c | 17 ++++ net/bpf/bpf_dummy_struct_ops.c | 2 +- tools/testing/selftests/bpf/Makefile | 10 +- .../selftests/bpf/bpf_test_no_cfi/Makefile | 19 ++++ .../bpf/bpf_test_no_cfi/bpf_test_no_cfi.c | 93 +++++++++++++++++++ .../bpf/prog_tests/test_struct_ops_no_cfi.c | 38 ++++++++ tools/testing/selftests/bpf/testing_helpers.c | 4 +- tools/testing/selftests/bpf/testing_helpers.h | 2 + 8 files changed, 181 insertions(+), 4 deletions(-) create mode 100644 tools/testing/selftests/bpf/bpf_test_no_cfi/Makefile create mode 100644 tools/testing/selftests/bpf/bpf_test_no_cfi/bpf_test_no_cfi.c create mode 100644 tools/testing/selftests/bpf/prog_tests/test_struct_ops_no_cfi.c -- 2.34.1
