From: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
commit 5b029a32cfe4600f5e10e36b41778506b90fd4de upstream.
Commit 457f44363a88 ("bpf: Implement BPF ring buffer and verifier support
for it") extended check_map_func_compatibility() by enforcing map -> helper
function match, but not helper -> map type match.
Due to this all of the bpf_ringbuf_*() helper functions could be used with
a wrong map type such as array or hash map, leading to invalid access due
to type confusion.
Also, both BPF_FUNC_ringbuf_{submit,discard} have ARG_PTR_TO_ALLOC_MEM as
argument and not a BPF map. Therefore, their check_map_func_compatibility()
presence is incorrect since it's only for map type checking.
Fixes: 457f44363a88 ("bpf: Implement BPF ring buffer and verifier support for it")
Reported-by: Ryota Shiga (Flatt Security)
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Acked-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/bpf/verifier.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5148,8 +5148,6 @@ static int check_map_func_compatibility(
case BPF_MAP_TYPE_RINGBUF:
if (func_id != BPF_FUNC_ringbuf_output &&
func_id != BPF_FUNC_ringbuf_reserve &&
- func_id != BPF_FUNC_ringbuf_submit &&
- func_id != BPF_FUNC_ringbuf_discard &&
func_id != BPF_FUNC_ringbuf_query)
goto error;
break;
@@ -5258,6 +5256,12 @@ static int check_map_func_compatibility(
if (map->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY)
goto error;
break;
+ case BPF_FUNC_ringbuf_output:
+ case BPF_FUNC_ringbuf_reserve:
+ case BPF_FUNC_ringbuf_query:
+ if (map->map_type != BPF_MAP_TYPE_RINGBUF)
+ goto error;
+ break;
case BPF_FUNC_get_stackid:
if (map->map_type != BPF_MAP_TYPE_STACK_TRACE)
goto error;
