If the test description is longer than the status alignment the parameter 'n' to putcharn() would lead to a signed underflow that then gets converted to a very large unsigned value. This in turn leads out-of-bound writes in memset() crashing the application.

The failure case of EXPECT_PTRER() used in "mmap_bad" exhibits this exact behavior.

Fixes: 8a27526f49f9 ("selftests/nolibc: add EXPECT_PTREQ, EXPECT_PTRNE and EXPECT_PTRER") Signed-off-by: Thomas Weißschuh linux@weissschuh.net --- tools/testing/selftests/nolibc/nolibc-test.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c index 03b1d30f5507..9b76603e4ce3 100644 --- a/tools/testing/selftests/nolibc/nolibc-test.c +++ b/tools/testing/selftests/nolibc/nolibc-test.c @@ -151,7 +151,8 @@ static void result(int llen, enum RESULT r) else msg = "[FAIL]";

- putcharn(' ', 64 - llen); + if (llen < 64) + putcharn(' ', 64 - llen); puts(msg); }

--- base-commit: dfef4fc45d5713eb23d87f0863aff9c33bd4bfaf change-id: 20230726-nolibc-result-width-1f4b0b4f3ca0

Best regards,