selftests/bpf: Add test cases to test narrower ctx field loads

Add test cases in test_verifier and test_progs.
Negative tests are added in test_verifier as well.
The test in test_progs will compare the value of narrower ctx field
load result vs. the masked value of normal full-field load result,
and will fail if they are not the same.

Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 21 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
index f10493d4c37c..5855cd3d3d45 100644
--- a/tools/testing/selftests/bpf/test_progs.c
+++ b/tools/testing/selftests/bpf/test_progs.c
@@ -484,6 +484,26 @@ done:
 		bpf_object__close(objs[i]);
 }
 
+static void test_pkt_md_access(void)
+{
+	const char *file = "./test_pkt_md_access.o";
+	struct bpf_object *obj;
+	__u32 duration, retval;
+	int err, prog_fd;
+
+	err = bpf_prog_load(file, BPF_PROG_TYPE_SCHED_CLS, &obj, &prog_fd);
+	if (err)
+		return;
+
+	err = bpf_prog_test_run(prog_fd, 10, &pkt_v4, sizeof(pkt_v4),
+				NULL, NULL, &retval, &duration);
+	CHECK(err || retval, "",
+	      "err %d errno %d retval %d duration %d\n",
+	      err, errno, retval, duration);
+
+	bpf_object__close(obj);
+}
+
 int main(void)
 {
 	struct rlimit rinf = { RLIM_INFINITY, RLIM_INFINITY };
@@ -495,6 +515,7 @@ int main(void)
 	test_l4lb();
 	test_tcp_estats();
 	test_bpf_obj_id();
+	test_pkt_md_access();
 
 	printf("Summary: %d PASSED, %d FAILED\n", pass_cnt, error_cnt);
 	return error_cnt ? EXIT_FAILURE : EXIT_SUCCESS;