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From:   Kees Cook <keescook@chromium.org>
To:     Eric Biederman <ebiederm@xmission.com>
Cc:     Kees Cook <keescook@chromium.org>,
        Alexey Dobriyan <adobriyan@gmail.com>,
        Shuah Khan <shuah@kernel.org>, linux-kselftest@vger.kernel.org,
        Ariadne Conill <ariadne@dereferenced.org>,
        Michael Kerrisk <mtk.manpages@gmail.com>,
        Matthew Wilcox <willy@infradead.org>,
        Christian Brauner <brauner@kernel.org>,
        Rich Felker <dalias@libc.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-hardening@vger.kernel.org
Subject: [PATCH] selftests/exec: Avoid future NULL argv execve warning
Date:   Mon, 31 Jan 2022 16:08:07 -0800
Message-Id: <20220201000807.2453486-1-keescook@chromium.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Build actual argv for launching recursion test to avoid future warning
about using an empty argv in execve().

Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: linux-kselftest@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 tools/testing/selftests/exec/recursion-depth.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/exec/recursion-depth.c b/tools/testing/selftests/exec/recursion-depth.c
index 2dbd5bc45b3e..35348db00c52 100644
--- a/tools/testing/selftests/exec/recursion-depth.c
+++ b/tools/testing/selftests/exec/recursion-depth.c
@@ -24,8 +24,14 @@
 #include <sys/mount.h>
 #include <unistd.h>
 
+#define FILENAME "/tmp/1"
+#define HASHBANG "#!" FILENAME "\n"
+
 int main(void)
 {
+	char * const argv[] = { FILENAME, NULL };
+	int rv;
+
 	if (unshare(CLONE_NEWNS) == -1) {
 		if (errno == ENOSYS || errno == EPERM) {
 			fprintf(stderr, "error: unshare, errno %d\n", errno);
@@ -44,21 +50,19 @@ int main(void)
 		return 1;
 	}
 
-#define FILENAME "/tmp/1"
 
 	int fd = creat(FILENAME, 0700);
 	if (fd == -1) {
 		fprintf(stderr, "error: creat, errno %d\n", errno);
 		return 1;
 	}
-#define S "#!" FILENAME "\n"
-	if (write(fd, S, strlen(S)) != strlen(S)) {
+	if (write(fd, HASHBANG, strlen(HASHBANG)) != strlen(HASHBANG)) {
 		fprintf(stderr, "error: write, errno %d\n", errno);
 		return 1;
 	}
 	close(fd);
 
-	int rv = execve(FILENAME, NULL, NULL);
+	rv = execve(FILENAME, argv, NULL);
 	if (rv == -1 && errno == ELOOP) {
 		return 0;
 	}
-- 
2.30.2