The current map_check_btf() in BPF_MAP_TYPE_ARRAY rejects
'> map->value_size' to ensure map_seq_show_elem() will not
access things beyond an array element.
Yonghong suggested that using '!=' is a more correct
check. The 8 bytes round_up on value_size is stored
in array->elem_size. Hence, using '!=' on map->value_size
is a proper check.
This patch also adds new tests to check the btf array
key type and value type. Two of these new tests verify
the btf's value_size (the change in this patch).
It also fixes two existing tests that wrongly encoded
a btf's type size (pprint_test) and the value_type_id (in one
of the raw_tests[]). However, that do not affect these two
BTF verification tests before or after this test changes.
These two tests mainly failed at array creation time after
this patch.
Fixes: a26ca7c982cb ("bpf: btf: Add pretty print support to the basic arraymap")
Suggested-by: Yonghong Song
Acked-by: Yonghong Song
Signed-off-by: Martin KaFai Lau
---
kernel/bpf/arraymap.c | 2 +-
tools/testing/selftests/bpf/test_btf.c | 86 +-
2 files changed, 85 insertions(+), 3 deletions(-)
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index 544e58f5f642..2aa55d030c77 100644
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -378,7 +378,7 @@ static int array_map_check_btf(const struct bpf_map *map,
const struct btf *btf,
return -EINVAL;
value_type = btf_type_id_size(btf, _value_id, _size);
- if (!value_type || value_size > map->value_size)
+ if (!value_type || value_size != map->value_size)
return -EINVAL;
return 0;
diff --git a/tools/testing/selftests/bpf/test_btf.c
b/tools/testing/selftests/bpf/test_btf.c
index 402c0f7cc418..ffdd27737c9e 100644
--- a/tools/testing/selftests/bpf/test_btf.c
+++ b/tools/testing/selftests/bpf/test_btf.c
@@ -507,7 +507,7 @@ static struct btf_raw_test raw_tests[] = {
.key_size = sizeof(int),
.value_size = sizeof(void *) * 4,
.key_type_id = 1,
- .value_type_id = 4,
+ .value_type_id = 5,
.max_entries = 4,
},
@@ -1292,6 +1292,88 @@ static struct btf_raw_test raw_tests[] = {
.err_str = "type != 0",
},
+{
+ .descr = "arraymap invalid btf key (a bit field)",
+ .raw_types = {
+ /* int */ /* [1] */
+ BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),
+ /* 32 bit int with 32 bit offset */ /* [2] */
+ BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 32, 32, 8),
+ BTF_END_RAW,
+ },
+ .str_sec = "",
+ .str_sec_size = sizeof(""),
+ .map_type = BPF_MAP_TYPE_ARRAY,
+ .map_name = "array_map_check_btf",
+ .key_size = sizeof(int),
+ .value_size = sizeof(int),
+ .key_type_id = 2,
+ .value_type_id = 1,
+ .max_entries = 4,
+ .map_create_err = true,
+},
+
+{
+ .descr = "arraymap invalid btf key (!= 32 bits)",
+ .raw_types = {
+ /* int */ /* [1] */
+ BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),
+ /* 16 bit int with 0 bit offset */ /* [2] */
+ BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 16, 2),
+ BTF_END_RAW,
+ },
+ .str_sec = "",
+ .str_sec_size = sizeof(""),
+ .map_type = BPF_MAP_TYPE_ARRAY,
+ .map_name = "array_map_check_btf",
+ .key_size = sizeof(int),
+ .value_size = sizeof(int),
+ .key_type_id = 2,
+ .value_type_id = 1,
+ .max_entries = 4,
+ .map_create_err = true,
+},
+
+{
+ .descr = "arraymap invalid btf value (too small)",
+ .raw_types = {
+ /* int */ /* [1] */
+ BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),
+ BTF_END_RAW,
+ },
+ .str_sec = "",
+ .str_sec_size = sizeof(""),
+ .map_type = BPF_MAP_TYPE_ARRAY,
+ .map_name = "array_map_check_btf",
+ .key_size = sizeof(int),
+ /* btf_value_size < map->value_size */
+ .value_size = sizeof(__u64),
+ .key_type_id = 1,
+ .value_type_id = 1,
+ .max_entries = 4,
+ .map_create_err = true,
+},
+
+{
+ .descr = "arraymap invalid btf value (too big)",
+ .raw_types = {
+ /* int */ /* [1] */
+ BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),
+ BTF_END_RAW,
+ },
+ .str_sec = "",
+ .str_sec_size = sizeof(""),
+ .map_type = BPF_MAP_TYPE_ARRAY,
+ .map_name = "array_map_check_btf",
+ .key_size = sizeof(int),
+ /* btf_value_size > map->value_size */
+ .value_size = sizeof(__u16),
+ .key_type_id = 1,
+ .value_type_id = 1,
+ .max_entries = 4,
+ .map_create_err = true,
+},
+
}; /* struct btf_raw_test raw_tests[] */
static const char
