Subject: [PATCH] Add test for more file systems in landlock - ext4

[Saasha Gupta <saashaa1122@gmail.com>]

Date: Mon, 2 Apr 2024 19:59:56 +0530

RE: This patch is now properly preformatted.

Landlock LSM, a part of the security subsystem, has some tests in place
for synthetic filesystems such as tmpfs, proc, sysfs, etc. The goal of
the new issue, and hence this patch is to add tests for non synthetic
file systems, such as ext4, btrfs, etc

This patch adds tests for the ext4 file system. This includes creation
of a loop device (test-ext4.img) and formating with mkfs.

Signed-off-by: Saasha Gupta <saashaa1122@gmail.com>
---
 tools/testing/selftests/landlock/fs_test.c | 65 ++++++++++++++++++++++
 1 file changed, 65 insertions(+)

diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c
index 9a6036fbf..b2f2cd5a5 100644
--- a/tools/testing/selftests/landlock/fs_test.c
+++ b/tools/testing/selftests/landlock/fs_test.c
@@ -4675,6 +4675,14 @@ FIXTURE_VARIANT_ADD(layout3_fs, hostfs) {
 	.cwd_fs_magic = HOSTFS_SUPER_MAGIC,
 };
 
+/* Add more filesystems */
+FIXTURE_VARIANT_ADD(layout3_fs, ext4) {
+	.mnt = {
+		.type = "ext4",
+	},
+	.file_path = TMP_DIR "/dir/file",
+};
+
 FIXTURE_SETUP(layout3_fs)
 {
 	struct stat statbuf;
@@ -4728,6 +4736,63 @@ FIXTURE_SETUP(layout3_fs)
 		self->has_created_file = true;
 		clear_cap(_metadata, CAP_DAC_OVERRIDE);
 	}
+
+	/* Create non synthetic file system - ext4 */
+	if (stat(self->dir_path, &statbuf) != 0) {
+		pid_t pid = fork();
+
+		if (pid == -1) {
+			perror("Failed to fork");
+			exit(EXIT_FAILURE);
+		} else if (pid == 0) {
+			static const fallocate_argv[] = { "fallocate", "--length",
+						   "4M", "test-ext4.img",
+						   NULL };
+			execvp(fallocate_argv[0], fallocate_argv);
+			perror("execvp failed");
+			exit(EXIT_FAILURE);
+		} else {
+			int status;
+
+			if (waitpid(pid, &status, 0) == -1) {
+				perror("waitpid failed");
+				exit(EXIT_FAILURE);
+			}
+			if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
+				TH_LOG(stderr,
+					"Failed to create ext4 filesystem image: fallocate failed\n");
+				exit(EXIT_FAILURE);
+			}
+		}
+	}
+
+	/* Formate and mount non synthetic file system - ext4 */
+	if (stat("mnt", &statbuf) != 0) {
+		pid_t pid = fork();
+
+		if (pid == -1) {
+			perror("Failed to fork");
+			exit(EXIT_FAILURE);
+		} else if (pid == 0) {
+			static const mkfs_argv[] = { "mkfs.ext4", "-q",
+					      "test-ext4.img", "mnt", NULL };
+			execvp(mkfs_argv[0], mkfs_argv);
+			perror("execvp failed");
+			exit(EXIT_FAILURE);
+		} else {
+			int status;
+
+			if (waitpid(pid, &status, 0) == -1) {
+				perror("waitpid failed");
+				exit(EXIT_FAILURE);
+			}
+			if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
+				TH_LOG(stderr,
+					"Failed to format ext4 filesystem image: mkfs.ext4 failed\n");
+				exit(EXIT_FAILURE);
+			}
+		}
+	}
 }
 
 FIXTURE_TEARDOWN(layout3_fs)
-- 
2.44.0