Merge tag 'landlock-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mic/linux

Pull landlock updates from Mickaël Salaün:
 "This brings ioctl control to Landlock, contributed by Günther Noack.
  This also adds him as a Landlock reviewer, and fixes an issue in the
  sample"

* tag 'landlock-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mic/linux:
  MAINTAINERS: Add Günther Noack as Landlock reviewer
  fs/ioctl: Add a comment to keep the logic in sync with LSM policies
  MAINTAINERS: Notify Landlock maintainers about changes to fs/ioctl.c
  landlock: Document IOCTL support
  samples/landlock: Add support for LANDLOCK_ACCESS_FS_IOCTL_DEV
  selftests/landlock: Exhaustive test for the IOCTL allow-list
  selftests/landlock: Check IOCTL restrictions for named UNIX domain sockets
  selftests/landlock: Test IOCTLs on named pipes
  selftests/landlock: Test ioctl(2) and ftruncate(2) with open(O_PATH)
  selftests/landlock: Test IOCTL with memfds
  selftests/landlock: Test IOCTL support
  landlock: Add IOCTL access right for character and block devices
  samples/landlock: Fix incorrect free in populate_ruleset_net

2 files changed, 477 insertions, 12 deletions

diff --git a/tools/testing/selftests/landlock/base_test.c b/tools/testing/selftests/landlock/base_test.c
index a6f89aaea77d..3c1e9f35b531 100644
--- a/tools/testing/selftests/landlock/base_test.c
+++ b/tools/testing/selftests/landlock/base_test.c
@@ -75,7 +75,7 @@ TEST(abi_version)
 	const struct landlock_ruleset_attr ruleset_attr = {
 		.handled_access_fs = LANDLOCK_ACCESS_FS_READ_FILE,
 	};
-	ASSERT_EQ(4, landlock_create_ruleset(NULL, 0,
+	ASSERT_EQ(5, landlock_create_ruleset(NULL, 0,
 					     LANDLOCK_CREATE_RULESET_VERSION));
 
 	ASSERT_EQ(-1, landlock_create_ruleset(&ruleset_attr, 0,
diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c
index 27744524df51..6b5a9ff88c3d 100644
--- a/tools/testing/selftests/landlock/fs_test.c
+++ b/tools/testing/selftests/landlock/fs_test.c
@@ -8,22 +8,34 @@
  */
 
 #define _GNU_SOURCE
+#include <asm/termbits.h>
 #include <fcntl.h>
 #include <libgen.h>
+#include <linux/fiemap.h>
 #include <linux/landlock.h>
 #include <linux/magic.h>
 #include <sched.h>
+#include <stddef.h>
 #include <stdio.h>
 #include <string.h>
 #include <sys/capability.h>
+#include <sys/ioctl.h>
 #include <sys/mount.h>
 #include <sys/prctl.h>
 #include <sys/sendfile.h>
+#include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/sysmacros.h>
+#include <sys/un.h>
 #include <sys/vfs.h>
 #include <unistd.h>
 
+/*
+ * Intentionally included last to work around header conflict.
+ * See https://sourceware.org/glibc/wiki/Synchronizing_Headers.
+ */
+#include <linux/fs.h>
+
 #include "common.h"
 
 #ifndef renameat2
@@ -536,9 +548,10 @@ TEST_F_FORK(layout1, inval)
 	LANDLOCK_ACCESS_FS_EXECUTE | \
 	LANDLOCK_ACCESS_FS_WRITE_FILE | \
 	LANDLOCK_ACCESS_FS_READ_FILE | \
-	LANDLOCK_ACCESS_FS_TRUNCATE)
+	LANDLOCK_ACCESS_FS_TRUNCATE | \
+	LANDLOCK_ACCESS_FS_IOCTL_DEV)
 
-#define ACCESS_LAST LANDLOCK_ACCESS_FS_TRUNCATE
+#define ACCESS_LAST LANDLOCK_ACCESS_FS_IOCTL_DEV
 
 #define ACCESS_ALL ( \
 	ACCESS_FILE | \
@@ -743,6 +756,9 @@ static int create_ruleset(struct __test_metadata *const _metadata,
 	}
 
 	for (i = 0; rules[i].path; i++) {
+		if (!rules[i].access)
+			continue;
+
 		add_path_beneath(_metadata, ruleset_fd, rules[i].access,
 				 rules[i].path);
 	}
@@ -3451,7 +3467,7 @@ TEST_F_FORK(layout1, truncate_unhandled)
 			      LANDLOCK_ACCESS_FS_WRITE_FILE;
 	int ruleset_fd;
 
-	/* Enable Landlock. */
+	/* Enables Landlock. */
 	ruleset_fd = create_ruleset(_metadata, handled, rules);
 
 	ASSERT_LE(0, ruleset_fd);
@@ -3534,7 +3550,7 @@ TEST_F_FORK(layout1, truncate)
 			      LANDLOCK_ACCESS_FS_TRUNCATE;
 	int ruleset_fd;
 
-	/* Enable Landlock. */
+	/* Enables Landlock. */
 	ruleset_fd = create_ruleset(_metadata, handled, rules);
 
 	ASSERT_LE(0, ruleset_fd);
@@ -3760,7 +3776,7 @@ TEST_F_FORK(ftruncate, open_and_ftruncate)
 	};
 	int fd, ruleset_fd;
 
-	/* Enable Landlock. */
+	/* Enables Landlock. */
 	ruleset_fd = create_ruleset(_metadata, variant->handled, rules);
 	ASSERT_LE(0, ruleset_fd);
 	enforce_ruleset(_metadata, ruleset_fd);
@@ -3837,22 +3853,471 @@ TEST_F_FORK(ftruncate, open_and_ftruncate_in_different_processes)
 	ASSERT_EQ(0, close(socket_fds[1]));
 }
 
-TEST(memfd_ftruncate)
+/* Invokes the FS_IOC_GETFLAGS IOCTL and returns its errno or 0. */
+static int test_fs_ioc_getflags_ioctl(int fd)
 {
-	int fd;
+	uint32_t flags;
+
+	if (ioctl(fd, FS_IOC_GETFLAGS, &flags) < 0)
+		return errno;
+	return 0;
+}
+
+TEST(memfd_ftruncate_and_ioctl)
+{
+	const struct landlock_ruleset_attr attr = {
+		.handled_access_fs = ACCESS_ALL,
+	};
+	int ruleset_fd, fd, i;
+
+	/*
+	 * We exercise the same test both with and without Landlock enabled, to
+	 * ensure that it behaves the same in both cases.
+	 */
+	for (i = 0; i < 2; i++) {
+		/* Creates a new memfd. */
+		fd = memfd_create("name", MFD_CLOEXEC);
+		ASSERT_LE(0, fd);
+
+		/*
+		 * Checks that operations associated with the opened file
+		 * (ftruncate, ioctl) are permitted on file descriptors that are
+		 * created in ways other than open(2).
+		 */
+		EXPECT_EQ(0, test_ftruncate(fd));
+		EXPECT_EQ(0, test_fs_ioc_getflags_ioctl(fd));
+
+		ASSERT_EQ(0, close(fd));
+
+		/* Enables Landlock. */
+		ruleset_fd = landlock_create_ruleset(&attr, sizeof(attr), 0);
+		ASSERT_LE(0, ruleset_fd);
+		enforce_ruleset(_metadata, ruleset_fd);
+		ASSERT_EQ(0, close(ruleset_fd));
+	}
+}
+
+static int test_fionread_ioctl(int fd)
+{
+	size_t sz = 0;
+
+	if (ioctl(fd, FIONREAD, &sz) < 0 && errno == EACCES)
+		return errno;
+	return 0;
+}
+
+TEST_F_FORK(layout1, o_path_ftruncate_and_ioctl)
+{
+	const struct landlock_ruleset_attr attr = {
+		.handled_access_fs = ACCESS_ALL,
+	};
+	int ruleset_fd, fd;
+
+	/*
+	 * Checks that for files opened with O_PATH, both ioctl(2) and
+	 * ftruncate(2) yield EBADF, as it is documented in open(2) for the
+	 * O_PATH flag.
+	 */
+	fd = open(dir_s1d1, O_PATH | O_CLOEXEC);
+	ASSERT_LE(0, fd);
+
+	EXPECT_EQ(EBADF, test_ftruncate(fd));
+	EXPECT_EQ(EBADF, test_fs_ioc_getflags_ioctl(fd));
+
+	ASSERT_EQ(0, close(fd));
+
+	/* Enables Landlock. */
+	ruleset_fd = landlock_create_ruleset(&attr, sizeof(attr), 0);
+	ASSERT_LE(0, ruleset_fd);
+	enforce_ruleset(_metadata, ruleset_fd);
+	ASSERT_EQ(0, close(ruleset_fd));
+
+	/*
+	 * Checks that after enabling Landlock,
+	 * - the file can still be opened with O_PATH
+	 * - both ioctl and truncate still yield EBADF (not EACCES).
+	 */
+	fd = open(dir_s1d1, O_PATH | O_CLOEXEC);
+	ASSERT_LE(0, fd);
+
+	EXPECT_EQ(EBADF, test_ftruncate(fd));
+	EXPECT_EQ(EBADF, test_fs_ioc_getflags_ioctl(fd));
+
+	ASSERT_EQ(0, close(fd));
+}
+
+/*
+ * ioctl_error - generically call the given ioctl with a pointer to a
+ * sufficiently large zeroed-out memory region.
+ *
+ * Returns the IOCTLs error, or 0.
+ */
+static int ioctl_error(struct __test_metadata *const _metadata, int fd,
+		       unsigned int cmd)
+{
+	char buf[128]; /* sufficiently large */
+	int res, stdinbak_fd;
+
+	/*
+	 * Depending on the IOCTL command, parts of the zeroed-out buffer might
+	 * be interpreted as file descriptor numbers.  We do not want to
+	 * accidentally operate on file descriptor 0 (stdin), so we temporarily
+	 * move stdin to a different FD and close FD 0 for the IOCTL call.
+	 */
+	stdinbak_fd = dup(0);
+	ASSERT_LT(0, stdinbak_fd);
+	ASSERT_EQ(0, close(0));
+
+	/* Invokes the IOCTL with a zeroed-out buffer. */
+	bzero(&buf, sizeof(buf));
+	res = ioctl(fd, cmd, &buf);
+
+	/* Restores the old FD 0 and closes the backup FD. */
+	ASSERT_EQ(0, dup2(stdinbak_fd, 0));
+	ASSERT_EQ(0, close(stdinbak_fd));
+
+	if (res < 0)
+		return errno;
+
+	return 0;
+}
+
+/* Define some linux/falloc.h IOCTL commands which are not available in uapi headers. */
+struct space_resv {
+	__s16 l_type;
+	__s16 l_whence;
+	__s64 l_start;
+	__s64 l_len; /* len == 0 means until end of file */
+	__s32 l_sysid;
+	__u32 l_pid;
+	__s32 l_pad[4]; /* reserved area */
+};
+
+#define FS_IOC_RESVSP _IOW('X', 40, struct space_resv)
+#define FS_IOC_UNRESVSP _IOW('X', 41, struct space_resv)
+#define FS_IOC_RESVSP64 _IOW('X', 42, struct space_resv)
+#define FS_IOC_UNRESVSP64 _IOW('X', 43, struct space_resv)
+#define FS_IOC_ZERO_RANGE _IOW('X', 57, struct space_resv)
+
+/*
+ * Tests a series of blanket-permitted and denied IOCTLs.
+ */
+TEST_F_FORK(layout1, blanket_permitted_ioctls)
+{
+	const struct landlock_ruleset_attr attr = {
+		.handled_access_fs = LANDLOCK_ACCESS_FS_IOCTL_DEV,
+	};
+	int ruleset_fd, fd;
 
-	fd = memfd_create("name", MFD_CLOEXEC);
+	/* Enables Landlock. */
+	ruleset_fd = landlock_create_ruleset(&attr, sizeof(attr), 0);
+	ASSERT_LE(0, ruleset_fd);
+	enforce_ruleset(_metadata, ruleset_fd);
+	ASSERT_EQ(0, close(ruleset_fd));
+
+	fd = open("/dev/null", O_RDWR | O_CLOEXEC);
 	ASSERT_LE(0, fd);
 
 	/*
-	 * Checks that ftruncate is permitted on file descriptors that are
-	 * created in ways other than open(2).
+	 * Checks permitted commands.
+	 * These ones may return errors, but should not be blocked by Landlock.
+	 */
+	EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FIOCLEX));
+	EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FIONCLEX));
+	EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FIONBIO));
+	EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FIOASYNC));
+	EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FIOQSIZE));
+	EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FIFREEZE));
+	EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FITHAW));
+	EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FS_IOC_FIEMAP));
+	EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FIGETBSZ));
+	EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FICLONE));
+	EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FICLONERANGE));
+	EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FIDEDUPERANGE));
+	EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FS_IOC_GETFSUUID));
+	EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FS_IOC_GETFSSYSFSPATH));
+
+	/*
+	 * Checks blocked commands.
+	 * A call to a blocked IOCTL command always returns EACCES.
 	 */
-	EXPECT_EQ(0, test_ftruncate(fd));
+	EXPECT_EQ(EACCES, ioctl_error(_metadata, fd, FIONREAD));
+	EXPECT_EQ(EACCES, ioctl_error(_metadata, fd, FS_IOC_GETFLAGS));
+	EXPECT_EQ(EACCES, ioctl_error(_metadata, fd, FS_IOC_SETFLAGS));
+	EXPECT_EQ(EACCES, ioctl_error(_metadata, fd, FS_IOC_FSGETXATTR));
+	EXPECT_EQ(EACCES, ioctl_error(_metadata, fd, FS_IOC_FSSETXATTR));
+	EXPECT_EQ(EACCES, ioctl_error(_metadata, fd, FIBMAP));
+	EXPECT_EQ(EACCES, ioctl_error(_metadata, fd, FS_IOC_RESVSP));
+	EXPECT_EQ(EACCES, ioctl_error(_metadata, fd, FS_IOC_RESVSP64));
+	EXPECT_EQ(EACCES, ioctl_error(_metadata, fd, FS_IOC_UNRESVSP));
+	EXPECT_EQ(EACCES, ioctl_error(_metadata, fd, FS_IOC_UNRESVSP64));
+	EXPECT_EQ(EACCES, ioctl_error(_metadata, fd, FS_IOC_ZERO_RANGE));
+
+	/* Default case is also blocked. */
+	EXPECT_EQ(EACCES, ioctl_error(_metadata, fd, 0xc00ffeee));
 
 	ASSERT_EQ(0, close(fd));
 }
 
+/*
+ * Named pipes are not governed by the LANDLOCK_ACCESS_FS_IOCTL_DEV right,
+ * because they are not character or block devices.
+ */
+TEST_F_FORK(layout1, named_pipe_ioctl)
+{
+	pid_t child_pid;
+	int fd, ruleset_fd;
+	const char *const path = file1_s1d1;
+	const struct landlock_ruleset_attr attr = {
+		.handled_access_fs = LANDLOCK_ACCESS_FS_IOCTL_DEV,
+	};
+
+	ASSERT_EQ(0, unlink(path));
+	ASSERT_EQ(0, mkfifo(path, 0600));
+
+	/* Enables Landlock. */
+	ruleset_fd = landlock_create_ruleset(&attr, sizeof(attr), 0);
+	ASSERT_LE(0, ruleset_fd);
+	enforce_ruleset(_metadata, ruleset_fd);
+	ASSERT_EQ(0, close(ruleset_fd));
+
+	/* The child process opens the pipe for writing. */
+	child_pid = fork();
+	ASSERT_NE(-1, child_pid);
+	if (child_pid == 0) {
+		fd = open(path, O_WRONLY);
+		close(fd);
+		exit(0);
+	}
+
+	fd = open(path, O_RDONLY);
+	ASSERT_LE(0, fd);
+
+	/* FIONREAD is implemented by pipefifo_fops. */
+	EXPECT_EQ(0, test_fionread_ioctl(fd));
+
+	ASSERT_EQ(0, close(fd));
+	ASSERT_EQ(0, unlink(path));
+
+	ASSERT_EQ(child_pid, waitpid(child_pid, NULL, 0));
+}
+
+/* For named UNIX domain sockets, no IOCTL restrictions apply. */
+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;
+	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));
+	ASSERT_EQ(0, listen(srv_fd, 10 /* qlen */));
+
+	/* Enables Landlock. */
+	ruleset_fd = landlock_create_ruleset(&attr, sizeof(attr), 0);
+	ASSERT_LE(0, ruleset_fd);
+	enforce_ruleset(_metadata, ruleset_fd);
+	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);
+
+	size = offsetof(struct sockaddr_un, sun_path) + strlen(cli_un.sun_path);
+	ASSERT_EQ(0, bind(cli_fd, (struct sockaddr *)&cli_un, size));
+
+	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));
+
+	/* FIONREAD and other IOCTLs should not be forbidden. */
+	EXPECT_EQ(0, test_fionread_ioctl(cli_fd));
+
+	ASSERT_EQ(0, close(cli_fd));
+}
+
+/* clang-format off */
+FIXTURE(ioctl) {};
+
+FIXTURE_SETUP(ioctl) {};
+
+FIXTURE_TEARDOWN(ioctl) {};
+/* clang-format on */
+
+FIXTURE_VARIANT(ioctl)
+{
+	const __u64 handled;
+	const __u64 allowed;
+	const mode_t open_mode;
+	/*
+	 * FIONREAD is used as a characteristic device-specific IOCTL command.
+	 * It is implemented in fs/ioctl.c for regular files,
+	 * but we do not blanket-permit it for devices.
+	 */
+	const int expected_fionread_result;
+};
+
+/* clang-format off */
+FIXTURE_VARIANT_ADD(ioctl, handled_i_allowed_none) {
+	/* clang-format on */
+	.handled = LANDLOCK_ACCESS_FS_IOCTL_DEV,
+	.allowed = 0,
+	.open_mode = O_RDWR,
+	.expected_fionread_result = EACCES,
+};
+
+/* clang-format off */
+FIXTURE_VARIANT_ADD(ioctl, handled_i_allowed_i) {
+	/* clang-format on */
+	.handled = LANDLOCK_ACCESS_FS_IOCTL_DEV,
+	.allowed = LANDLOCK_ACCESS_FS_IOCTL_DEV,
+	.open_mode = O_RDWR,
+	.expected_fionread_result = 0,
+};
+
+/* clang-format off */
+FIXTURE_VARIANT_ADD(ioctl, unhandled) {
+	/* clang-format on */
+	.handled = LANDLOCK_ACCESS_FS_EXECUTE,
+	.allowed = LANDLOCK_ACCESS_FS_EXECUTE,
+	.open_mode = O_RDWR,
+	.expected_fionread_result = 0,
+};
+
+TEST_F_FORK(ioctl, handle_dir_access_file)
+{
+	const int flag = 0;
+	const struct rule rules[] = {
+		{
+			.path = "/dev",
+			.access = variant->allowed,
+		},
+		{},
+	};
+	int file_fd, ruleset_fd;
+
+	/* Enables Landlock. */
+	ruleset_fd = create_ruleset(_metadata, variant->handled, rules);
+	ASSERT_LE(0, ruleset_fd);
+	enforce_ruleset(_metadata, ruleset_fd);
+	ASSERT_EQ(0, close(ruleset_fd));
+
+	file_fd = open("/dev/zero", variant->open_mode);
+	ASSERT_LE(0, file_fd);
+
+	/* Checks that IOCTL commands return the expected errors. */
+	EXPECT_EQ(variant->expected_fionread_result,
+		  test_fionread_ioctl(file_fd));
+
+	/* Checks that unrestrictable commands are unrestricted. */
+	EXPECT_EQ(0, ioctl(file_fd, FIOCLEX));
+	EXPECT_EQ(0, ioctl(file_fd, FIONCLEX));
+	EXPECT_EQ(0, ioctl(file_fd, FIONBIO, &flag));
+	EXPECT_EQ(0, ioctl(file_fd, FIOASYNC, &flag));
+	EXPECT_EQ(0, ioctl(file_fd, FIGETBSZ, &flag));
+
+	ASSERT_EQ(0, close(file_fd));
+}
+
+TEST_F_FORK(ioctl, handle_dir_access_dir)
+{
+	const int flag = 0;
+	const struct rule rules[] = {
+		{
+			.path = "/dev",
+			.access = variant->allowed,
+		},
+		{},
+	};
+	int dir_fd, ruleset_fd;
+
+	/* Enables Landlock. */
+	ruleset_fd = create_ruleset(_metadata, variant->handled, rules);
+	ASSERT_LE(0, ruleset_fd);
+	enforce_ruleset(_metadata, ruleset_fd);
+	ASSERT_EQ(0, close(ruleset_fd));
+
+	/*
+	 * Ignore variant->open_mode for this test, as we intend to open a
+	 * directory.  If the directory can not be opened, the variant is
+	 * infeasible to test with an opened directory.
+	 */
+	dir_fd = open("/dev", O_RDONLY);
+	if (dir_fd < 0)
+		return;
+
+	/*
+	 * Checks that IOCTL commands return the expected errors.
+	 * We do not use the expected values from the fixture here.
+	 *
+	 * When using IOCTL on a directory, no Landlock restrictions apply.
+	 */
+	EXPECT_EQ(0, test_fionread_ioctl(dir_fd));
+
+	/* Checks that unrestrictable commands are unrestricted. */
+	EXPECT_EQ(0, ioctl(dir_fd, FIOCLEX));
+	EXPECT_EQ(0, ioctl(dir_fd, FIONCLEX));
+	EXPECT_EQ(0, ioctl(dir_fd, FIONBIO, &flag));
+	EXPECT_EQ(0, ioctl(dir_fd, FIOASYNC, &flag));
+	EXPECT_EQ(0, ioctl(dir_fd, FIGETBSZ, &flag));
+
+	ASSERT_EQ(0, close(dir_fd));
+}
+
+TEST_F_FORK(ioctl, handle_file_access_file)
+{
+	const int flag = 0;
+	const struct rule rules[] = {
+		{
+			.path = "/dev/zero",
+			.access = variant->allowed,
+		},
+		{},
+	};
+	int file_fd, ruleset_fd;
+
+	/* Enables Landlock. */
+	ruleset_fd = create_ruleset(_metadata, variant->handled, rules);
+	ASSERT_LE(0, ruleset_fd);
+	enforce_ruleset(_metadata, ruleset_fd);
+	ASSERT_EQ(0, close(ruleset_fd));
+
+	file_fd = open("/dev/zero", variant->open_mode);
+	ASSERT_LE(0, file_fd)
+	{
+		TH_LOG("Failed to open /dev/zero: %s", strerror(errno));
+	}
+
+	/* Checks that IOCTL commands return the expected errors. */
+	EXPECT_EQ(variant->expected_fionread_result,
+		  test_fionread_ioctl(file_fd));
+
+	/* Checks that unrestrictable commands are unrestricted. */
+	EXPECT_EQ(0, ioctl(file_fd, FIOCLEX));
+	EXPECT_EQ(0, ioctl(file_fd, FIONCLEX));
+	EXPECT_EQ(0, ioctl(file_fd, FIONBIO, &flag));
+	EXPECT_EQ(0, ioctl(file_fd, FIOASYNC, &flag));
+	EXPECT_EQ(0, ioctl(file_fd, FIGETBSZ, &flag));
+
+	ASSERT_EQ(0, close(file_fd));
+}
+
 /* clang-format off */
 FIXTURE(layout1_bind) {};
 /* clang-format on */