Commit 3881fdfe authored by Daniel Rosenberg's avatar Daniel Rosenberg Committed by Alexei Starovoitov
Browse files

selftests/bpf: Check overflow in optional buffer 



This ensures we still reject invalid memory accesses in buffers that are
marked optional.

Signed-off-by: default avatarDaniel Rosenberg <drosen@google.com>
Link: https://lore.kernel.org/r/20230506013134.2492210-4-drosen@google.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 1ce33b6c

tools/testing/selftests/bpf/progs/dynptr_fail.c

+20 −0
Original line number Diff line number Diff line
@@ -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;

}