From 9c5e490093e83e165022e0311bd7df5aa06cc860 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Thomas=20Wei=C3=9Fschuh?= Date: Thu, 3 Aug 2023 09:28:56 +0200 Subject: [PATCH] selftests/nolibc: prevent out of bounds access in expect_vfprintf MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit If read() fails and returns -1 (or returns garbage for some other reason) buf would be accessed out of bounds. Only use the return value of read() after it has been validated. Signed-off-by: Thomas Weißschuh Signed-off-by: Willy Tarreau --- tools/testing/selftests/nolibc/nolibc-test.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c index 23a5e4c570833..e2b70641a1e76 100644 --- a/tools/testing/selftests/nolibc/nolibc-test.c +++ b/tools/testing/selftests/nolibc/nolibc-test.c @@ -1051,7 +1051,6 @@ static int expect_vfprintf(int llen, int c, const char *expected, const char *fm lseek(fd, 0, SEEK_SET); r = read(fd, buf, sizeof(buf) - 1); - buf[r] = '\0'; fclose(memfile); @@ -1061,6 +1060,7 @@ static int expect_vfprintf(int llen, int c, const char *expected, const char *fm return 1; } + buf[r] = '\0'; llen += printf(" \"%s\" = \"%s\"", expected, buf); ret = strncmp(expected, buf, c); -- 2.30.2