From da6c7faeb103c493e505e87643272f70be586635 Mon Sep 17 00:00:00 2001 From: Yoshiki Komachi Date: Tue, 10 Mar 2020 16:32:29 +0900 Subject: [PATCH 1/2] bpf/btf: Fix BTF verification of enum members in struct/union btf_enum_check_member() was currently sure to recognize the size of "enum" type members in struct/union as the size of "int" even if its size was packed. This patch fixes BTF enum verification to use the correct size of member in BPF programs. Fixes: 179cde8cef7e ("bpf: btf: Check members of struct/union") Signed-off-by: Yoshiki Komachi Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/1583825550-18606-2-git-send-email-komachi.yoshiki@gmail.com --- kernel/bpf/btf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 787140095e58..32ab9225026e 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -2418,7 +2418,7 @@ static int btf_enum_check_member(struct btf_verifier_env *env, struct_size = struct_type->size; bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off); - if (struct_size - bytes_offset < sizeof(int)) { + if (struct_size - bytes_offset < member_type->size) { btf_verifier_log_member(env, struct_type, member, "Member exceeds struct_size"); return -EINVAL; From 6ffe559a77d1c963a3567f7a39a5419bdcdc4f1c Mon Sep 17 00:00:00 2001 From: Yoshiki Komachi Date: Tue, 10 Mar 2020 16:32:30 +0900 Subject: [PATCH 2/2] selftests/bpf: Add test for the packed enum member in struct/union Add a simple test to the existing selftest program in order to make sure that a packed enum member in struct unexceeds the struct_size. Signed-off-by: Yoshiki Komachi Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/1583825550-18606-3-git-send-email-komachi.yoshiki@gmail.com --- tools/testing/selftests/bpf/test_btf.c | 42 ++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) diff --git a/tools/testing/selftests/bpf/test_btf.c b/tools/testing/selftests/bpf/test_btf.c index 93040ca83e60..8da77cda5f4a 100644 --- a/tools/testing/selftests/bpf/test_btf.c +++ b/tools/testing/selftests/bpf/test_btf.c @@ -1062,6 +1062,48 @@ static struct btf_raw_test raw_tests[] = { .err_str = "Member exceeds struct_size", }, +/* Test member unexceeds the size of struct + * + * enum E { + * E0, + * E1, + * }; + * + * struct A { + * char m; + * enum E __attribute__((packed)) n; + * }; + */ +{ + .descr = "size check test #5", + .raw_types = { + /* int */ /* [1] */ + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, sizeof(int)), + /* char */ /* [2] */ + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 8, 1), + /* enum E { */ /* [3] */ + BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_ENUM, 0, 2), 1), + BTF_ENUM_ENC(NAME_TBD, 0), + BTF_ENUM_ENC(NAME_TBD, 1), + /* } */ + /* struct A { */ /* [4] */ + BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 2), 2), + BTF_MEMBER_ENC(NAME_TBD, 2, 0), /* char m; */ + BTF_MEMBER_ENC(NAME_TBD, 3, 8),/* enum E __attribute__((packed)) n; */ + /* } */ + BTF_END_RAW, + }, + .str_sec = "\0E\0E0\0E1\0A\0m\0n", + .str_sec_size = sizeof("\0E\0E0\0E1\0A\0m\0n"), + .map_type = BPF_MAP_TYPE_ARRAY, + .map_name = "size_check5_map", + .key_size = sizeof(int), + .value_size = 2, + .key_type_id = 1, + .value_type_id = 4, + .max_entries = 4, +}, + /* typedef const void * const_void_ptr; * struct A { * const_void_ptr m;