[PATCH] selinux: clean up selinuxfs resources on init failure

[Haoxiang Li]

init_sel_fs() creates the selinuxfs mount point and registers the
filesystem before mounting selinuxfs internally. If kern_mount()
or the subsequent lookup of the null file fails, the function
returns without undoing the resources that were already registered.

Add the missing error unwinding so the internal mount, filesystem
registration, and sysfs mount point are released as appropriate.

Signed-off-by: Haoxiang Li <haoxiang_li2024@xxxxxxx>
---
 security/selinux/selinuxfs.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index 5aaaf69410bb..c7d91476971c 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -1984,17 +1984,15 @@ int __init init_sel_fs(void)
 		return err;
 
 	err = register_filesystem(&sel_fs_type);
-	if (err) {
-		sysfs_remove_mount_point(fs_kobj, "selinux");
-		return err;
-	}
+	if (err)
+		goto err_remove_mount_point;
 
 	selinux_null.mnt = kern_mount(&sel_fs_type);
 	if (IS_ERR(selinux_null.mnt)) {
 		pr_err("selinuxfs:  could not mount!\n");
 		err = PTR_ERR(selinux_null.mnt);
 		selinux_null.mnt = NULL;
-		return err;
+		goto err_unregister_fs;
 	}
 
 	selinux_null.dentry = try_lookup_noperm(&null_name,
@@ -2003,7 +2001,7 @@ int __init init_sel_fs(void)
 		pr_err("selinuxfs:  could not lookup null!\n");
 		err = PTR_ERR(selinux_null.dentry);
 		selinux_null.dentry = NULL;
-		return err;
+		goto err_unmount;
 	}
 
 	/*
@@ -2012,5 +2010,14 @@ int __init init_sel_fs(void)
 	 */
 	(void) selinux_kernel_status_page();
 
+	return 0;
+
+err_unmount:
+	kern_unmount(selinux_null.mnt);
+	selinux_null.mnt = NULL;
+err_unregister_fs:
+	unregister_filesystem(&sel_fs_type);
+err_remove_mount_point:
+	sysfs_remove_mount_point(fs_kobj, "selinux");
 	return err;
 }
-- 
2.25.1