[bpf-next v2 02/10] selftests/bpf: Avoid a clobbering of errno

Krzesimir Nowak
2019-06-25T19:42:52Z

Save errno right after bpf_prog_test_run returns, so we later check
the error code actually set by bpf_prog_test_run, not by some libcap
function.

Cc: Daniel Borkmann <daniel@iogearbox.net>
Fixes: 832c6f2c29ec ("bpf: test make sure to run unpriv test cases in test_verifier")
Signed-off-by: Krzesimir Nowak <krzesimir@kinvolk.io>
---
tools/testing/selftests/bpf/test_verifier.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 9e17bda016ef..12589da13487 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -824,15 +824,17 @@ static int do_prog_test_run(int fd_prog, bool unpriv, uint32_t expected_val,
__u32 size_tmp = sizeof(tmp);
uint32_t retval;
int err;
+ int saved_errno;

if (unpriv)
set_admin(true);
err = bpf_prog_test_run(fd_prog, 1, data, size_data,
tmp, &size_tmp, &retval, NULL);
+ saved_errno = errno;
if (unpriv)
set_admin(false);
if (err) {
- switch (errno) {
+ switch (saved_errno) {
case 524/*ENOTSUPP*/:
printf("Did not run the program (not supported) ");
return 0;
--
2.20.1