This ensures we still reject invalid memory accesses in buffers that are
marked optional.
Signed-off-by: Daniel Rosenberg <drosen@xxxxxxxxxx>
---
.../testing/selftests/bpf/progs/dynptr_fail.c | 20 +++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/tools/testing/selftests/bpf/progs/dynptr_fail.c b/tools/testing/selftests/bpf/progs/dynptr_fail.c
index efe4ce72d00e..c2f0e18af951 100644
--- a/tools/testing/selftests/bpf/progs/dynptr_fail.c
+++ b/tools/testing/selftests/bpf/progs/dynptr_fail.c
@@ -1665,3 +1665,23 @@ int clone_xdp_packet_data(struct xdp_md *xdp)
return 0;
}
+
+/* Buffers that are provided must be sufficiently long */
+SEC("?cgroup_skb/egress")
+__failure __msg("memory, len pair leads to invalid memory access")
+int test_dynptr_skb_small_buff(struct __sk_buff *skb)
+{
+ struct bpf_dynptr ptr;
+ char buffer[8] = {};
+ __u64 *data;
+
+ if (bpf_dynptr_from_skb(skb, 0, &ptr)) {
+ err = 1;
+ return 1;
+ }
+
+ /* This may return NULL. SKB may require a buffer */
+ data = bpf_dynptr_slice(&ptr, 0, buffer, 9);
+
+ return !!data;
+}
--
2.40.1.521.gf1e218fcd8-goog
