Commit 7f9ee5fc authored by Shardul Bankar's avatar Shardul Bankar Committed by Martin KaFai Lau
Browse files

bpf: test_run: Fix ctx leak in bpf_prog_test_run_xdp error path 



Fix a memory leak in bpf_prog_test_run_xdp() where the context buffer
allocated by bpf_ctx_init() is not freed when the function returns early
due to a data size check.

On the failing path:
  ctx = bpf_ctx_init(...);
  if (kattr->test.data_size_in - meta_sz < ETH_HLEN)
      return -EINVAL;

The early return bypasses the cleanup label that kfree()s ctx, leading to a
leak detectable by kmemleak under fuzzing. Change the return to jump to the
existing free_ctx label.

Fixes: fe9544ed ("bpf: Support specifying linear xdp packet data size for BPF_PROG_TEST_RUN")
Reported-by: BPF Runtime Fuzzer (BRF)
Signed-off-by: default avatarShardul Bankar <shardulsb08@gmail.com>
Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
Acked-by: default avatarJiri Olsa <jolsa@kernel.org>
Acked-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://patch.msgid.link/20251014120037.1981316-1-shardulsb08@gmail.com
parent 3a866087

net/bpf/test_run.c

+1 −1
Original line number Diff line number Diff line
@@ -1269,7 +1269,7 @@ int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr, 
		goto free_ctx;



	if (kattr->test.data_size_in - meta_sz < ETH_HLEN)

		return -EINVAL;

		goto free_ctx;



	data = bpf_test_init(kattr, linear_sz, max_linear_sz, headroom, tailroom);

	if (IS_ERR(data)) {