From da6c7faeb103c493e505e87643272f70be586635 Mon Sep 17 00:00:00 2001
From: Yoshiki Komachi <komachi.yoshiki@gmail.com>
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 <komachi.yoshiki@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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 787140095e58d..32ab9225026eb 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 <komachi.yoshiki@gmail.com>
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 <komachi.yoshiki@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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 93040ca83e604..8da77cda5f4a5 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;