[PATCH bpf-next 1/2] bpf: btf: Check array t->size

Martin KaFai Lau
2018-06-02T16:06:54Z

This patch ensures array's t->size is 0.

The array size is decided by its individual elem's size and the
number of elements. Hence, t->size is not used and
it must be 0.

A test case is added to test_btf.c

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
---
kernel/bpf/btf.c | 5 +++++
tools/testing/selftests/bpf/test_btf.c | 23 +++++++++++++++++++++++
2 files changed, 28 insertions(+)

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 3d20aa1f4b54..84ad532f2854 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -1342,6 +1342,11 @@ static s32 btf_array_check_meta(struct btf_verifier_env *env,
return -EINVAL;
}

+ if (t->size) {
+ btf_verifier_log_type(env, t, "size != 0");
+ return -EINVAL;
+ }
+
/* Array elem type and index type cannot be in type void,
* so !array->type and !array->index_type are not allowed.
*/
diff --git a/tools/testing/selftests/bpf/test_btf.c b/tools/testing/selftests/bpf/test_btf.c
index 35064df688c1..fd8246e84149 100644
--- a/tools/testing/selftests/bpf/test_btf.c
+++ b/tools/testing/selftests/bpf/test_btf.c
@@ -1179,6 +1179,29 @@ static struct btf_raw_test raw_tests[] = {
},

{
+ .descr = "array test. t->size != 0\"",
+ .raw_types = {
+ /* int */ /* [1] */
+ BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),
+ /* int[16] */ /* [2] */
+ BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_ARRAY, 0, 0), 1),
+ BTF_ARRAY_ENC(1, 1, 16),
+ BTF_END_RAW,
+ },
+ .str_sec = "",
+ .str_sec_size = sizeof(""),
+ .map_type = BPF_MAP_TYPE_ARRAY,
+ .map_name = "array_test_map",
+ .key_size = sizeof(int),
+ .value_size = sizeof(int),
+ .key_type_id = 1,
+ .value_type_id = 1,
+ .max_entries = 4,
+ .btf_load_err = true,
+ .err_str = "size != 0",
+},
+
+{
.descr = "int test. invalid int_data",
.raw_types = {
BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), 4),
--
2.9.5