[PATCH] selftests/landlock: NULL-terminate unix pathname addresses

[Matthieu Buffet <matthieu@buffet.re>]

The size of Unix pathname addresses is computed in selftests using
offsetof(struct sockaddr_un, sun_path) + strlen(xxx). It should have
been that +1, which makes addresses passed to the libc and kernel
non-NULL-terminated. unix_mkname_bsd() fixes that in Linux so there is
no harm, but just using sizeof(the address struct) should improve
readability.

Signed-off-by: Matthieu Buffet <matthieu@buffet.re>
---
Based on commit https://lore.kernel.org/linux-security-module/20251201003631.190817-1-matthieu@buffet.re/

 tools/testing/selftests/landlock/fs_test.c    | 24 +++++++++----------
 .../landlock/scoped_abstract_unix_test.c      | 21 +++++++---------
 2 files changed, 20 insertions(+), 25 deletions(-)

diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c
index 7d378bdf3bce..76491ba54dce 100644
--- a/tools/testing/selftests/landlock/fs_test.c
+++ b/tools/testing/selftests/landlock/fs_test.c
@@ -4362,22 +4362,24 @@ TEST_F_FORK(layout1, named_unix_domain_socket_ioctl)
 {
 	const char *const path = file1_s1d1;
 	int srv_fd, cli_fd, ruleset_fd;
-	socklen_t size;
-	struct sockaddr_un srv_un, cli_un;
+	struct sockaddr_un srv_un = {
+		.sun_family = AF_UNIX,
+	};
+	struct sockaddr_un cli_un = {
+		.sun_family = AF_UNIX,
+	};
 	const struct landlock_ruleset_attr attr = {
 		.handled_access_fs = LANDLOCK_ACCESS_FS_IOCTL_DEV,
 	};
 
 	/* Sets up a server */
-	srv_un.sun_family = AF_UNIX;
-	strncpy(srv_un.sun_path, path, sizeof(srv_un.sun_path));
-
 	ASSERT_EQ(0, unlink(path));
 	srv_fd = socket(AF_UNIX, SOCK_STREAM, 0);
 	ASSERT_LE(0, srv_fd);
 
-	size = offsetof(struct sockaddr_un, sun_path) + strlen(srv_un.sun_path);
-	ASSERT_EQ(0, bind(srv_fd, (struct sockaddr *)&srv_un, size));
+	strncpy(srv_un.sun_path, path, sizeof(srv_un.sun_path));
+	ASSERT_EQ(0, bind(srv_fd, (struct sockaddr *)&srv_un, sizeof(srv_un)));
+
 	ASSERT_EQ(0, listen(srv_fd, 10 /* qlen */));
 
 	/* Enables Landlock. */
@@ -4387,16 +4389,12 @@ TEST_F_FORK(layout1, named_unix_domain_socket_ioctl)
 	ASSERT_EQ(0, close(ruleset_fd));
 
 	/* Sets up a client connection to it */
-	cli_un.sun_family = AF_UNIX;
 	cli_fd = socket(AF_UNIX, SOCK_STREAM, 0);
 	ASSERT_LE(0, cli_fd);
 
-	bzero(&cli_un, sizeof(cli_un));
-	cli_un.sun_family = AF_UNIX;
 	strncpy(cli_un.sun_path, path, sizeof(cli_un.sun_path));
-	size = offsetof(struct sockaddr_un, sun_path) + strlen(cli_un.sun_path);
-
-	ASSERT_EQ(0, connect(cli_fd, (struct sockaddr *)&cli_un, size));
+	ASSERT_EQ(0,
+		  connect(cli_fd, (struct sockaddr *)&cli_un, sizeof(cli_un)));
 
 	/* FIONREAD and other IOCTLs should not be forbidden. */
 	EXPECT_EQ(0, test_fionread_ioctl(cli_fd));
diff --git a/tools/testing/selftests/landlock/scoped_abstract_unix_test.c b/tools/testing/selftests/landlock/scoped_abstract_unix_test.c
index 6825082c079c..2cdf1ba07016 100644
--- a/tools/testing/selftests/landlock/scoped_abstract_unix_test.c
+++ b/tools/testing/selftests/landlock/scoped_abstract_unix_test.c
@@ -779,7 +779,6 @@ FIXTURE_TEARDOWN(various_address_sockets)
 
 TEST_F(various_address_sockets, scoped_pathname_sockets)
 {
-	socklen_t size_stream, size_dgram;
 	pid_t child;
 	int status;
 	char buf_child, buf_parent;
@@ -798,12 +797,8 @@ TEST_F(various_address_sockets, scoped_pathname_sockets)
 	/* Pathname address. */
 	snprintf(stream_pathname_addr.sun_path,
 		 sizeof(stream_pathname_addr.sun_path), "%s", stream_path);
-	size_stream = offsetof(struct sockaddr_un, sun_path) +
-		      strlen(stream_pathname_addr.sun_path);
 	snprintf(dgram_pathname_addr.sun_path,
 		 sizeof(dgram_pathname_addr.sun_path), "%s", dgram_path);
-	size_dgram = offsetof(struct sockaddr_un, sun_path) +
-		     strlen(dgram_pathname_addr.sun_path);
 
 	/* Abstract address. */
 	memset(&stream_abstract_addr, 0, sizeof(stream_abstract_addr));
@@ -841,8 +836,9 @@ TEST_F(various_address_sockets, scoped_pathname_sockets)
 		/* Connects with pathname sockets. */
 		stream_pathname_socket = socket(AF_UNIX, SOCK_STREAM, 0);
 		ASSERT_LE(0, stream_pathname_socket);
-		ASSERT_EQ(0, connect(stream_pathname_socket,
-				     &stream_pathname_addr, size_stream));
+		ASSERT_EQ(0,
+			  connect(stream_pathname_socket, &stream_pathname_addr,
+				  sizeof(stream_pathname_addr)));
 		ASSERT_EQ(1, write(stream_pathname_socket, "b", 1));
 		EXPECT_EQ(0, close(stream_pathname_socket));
 
@@ -850,12 +846,13 @@ TEST_F(various_address_sockets, scoped_pathname_sockets)
 		dgram_pathname_socket = socket(AF_UNIX, SOCK_DGRAM, 0);
 		ASSERT_LE(0, dgram_pathname_socket);
 		err = sendto(dgram_pathname_socket, "c", 1, 0,
-			     &dgram_pathname_addr, size_dgram);
+			     &dgram_pathname_addr, sizeof(dgram_pathname_addr));
 		EXPECT_EQ(1, err);
 
 		/* Sends with connection. */
-		ASSERT_EQ(0, connect(dgram_pathname_socket,
-				     &dgram_pathname_addr, size_dgram));
+		ASSERT_EQ(0,
+			  connect(dgram_pathname_socket, &dgram_pathname_addr,
+				  sizeof(dgram_pathname_addr)));
 		ASSERT_EQ(1, write(dgram_pathname_socket, "d", 1));
 		EXPECT_EQ(0, close(dgram_pathname_socket));
 
@@ -910,13 +907,13 @@ TEST_F(various_address_sockets, scoped_pathname_sockets)
 	stream_pathname_socket = socket(AF_UNIX, SOCK_STREAM, 0);
 	ASSERT_LE(0, stream_pathname_socket);
 	ASSERT_EQ(0, bind(stream_pathname_socket, &stream_pathname_addr,
-			  size_stream));
+			  sizeof(stream_pathname_addr)));
 	ASSERT_EQ(0, listen(stream_pathname_socket, backlog));
 
 	dgram_pathname_socket = socket(AF_UNIX, SOCK_DGRAM, 0);
 	ASSERT_LE(0, dgram_pathname_socket);
 	ASSERT_EQ(0, bind(dgram_pathname_socket, &dgram_pathname_addr,
-			  size_dgram));
+			  sizeof(dgram_pathname_addr)));
 
 	/* Sets up abstract servers. */
 	stream_abstract_socket = socket(AF_UNIX, SOCK_STREAM, 0);

base-commit: c07e22414d18559b5c0fd5bc2c2f68f2903f1738
-- 
2.47.3