[PATCH 5.10 234/545] selftests/bpf: fix a test for snprintf() overflow

Greg Kroah-Hartman
2022-08-19T16:12:57Z

From: Dan Carpenter <dan.carpenter@oracle.com>

[ Upstream commit c5d22f4cfe8dfb93f1db0a1e7e2e7ebc41395d98 ]

The snprintf() function returns the number of bytes which *would*
have been copied if there were space. In other words, it can be
> sizeof(pin_path).

Fixes: c0fa1b6c3efc ("bpf: btf: Add BTF tests")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/r/YtZ+aD/tZMkgOUw+@kili
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/testing/selftests/bpf/prog_tests/btf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/btf.c b/tools/testing/selftests/bpf/prog_tests/btf.c
index 93162484c2ca..48b01150e703 100644
--- a/tools/testing/selftests/bpf/prog_tests/btf.c
+++ b/tools/testing/selftests/bpf/prog_tests/btf.c
@@ -4758,7 +4758,7 @@ static void do_test_pprint(int test_num)
ret = snprintf(pin_path, sizeof(pin_path), "%s/%s",
"/sys/fs/bpf", test->map_name);

- if (CHECK(ret == sizeof(pin_path), "pin_path %s/%s is too long",
+ if (CHECK(ret >= sizeof(pin_path), "pin_path %s/%s is too long",
"/sys/fs/bpf", test->map_name)) {
err = -1;
goto done;
--
2.35.1