lrwxrwxrwx is a common string seen in Linux and Unix-like operating systems when listing files, specifically referring to the file type and its permissions. It indicates that the entry is a symbolic link, and grants full read, write, and execute permissions to the file owner, the file's group, and all other users.
Understanding lrwxrwxrwx
This specific string can be broken down into two main parts: the initial character indicating the file type, and the subsequent nine characters representing the access permissions for different user categories.
1. The File Type: l
The first character, l, signifies that the entry is a symbolic link (often shortened to "symlink"). A symbolic link is essentially a pointer or a shortcut to another file or directory located elsewhere on the file system. It's similar to a shortcut in Windows. When you access a symbolic link, the operating system redirects you to the actual target file or directory.
Common file type characters include:
-: Regular filed: Directoryl: Symbolic linkc: Character device fileb: Block device files: Local socket filep: Named pipe (FIFO)
2. File Permissions: rwxrwxrwx
The remaining nine characters, rwxrwxrwx, define the access permissions for three distinct user categories:
- Owner Permissions (first
rwx): These permissions apply to the user who owns the file. - Group Permissions (second
rwx): These permissions apply to users who are members of the file's assigned group. - Others Permissions (third
rwx): These permissions apply to everyone else on the system who is not the owner and not part of the file's group.
Each set of three characters represents read (r), write (w), and execute (x) permissions. A hyphen (-) in any position indicates the absence of that particular permission.
Here's what each permission means:
| Permission | Description |
|---|---|
r (Read) |
For files: Allows viewing the file's content. For directories: Allows listing the contents of the directory (e.g., using ls). |
w (Write) |
For files: Allows modifying, saving changes to, or deleting the file. For directories: Allows creating, deleting, or renaming files and subdirectories within that directory. |
x (Execute) |
For files: Allows running the file as a program or script. For directories: Allows traversing into the directory (e.g., using cd). Without execute permission on a directory, you cannot access its contents, even with read permission. |
In the specific case of rwxrwxrwx:
- Owner (
rwx): The file owner can Read, Write, and eXecute the file. They have full control over it. - Group (
rwx): Users belonging to the file's group can also Read, Write, and eXecute the file. This means they have the same full access as the owner. - Others (
rwx): All other users on the system can also Read, Write, and eXecute the file. This grants full access to everyone else.
Practical Implications and Security
The lrwxrwxrwx permission set is highly permissive because it grants full read, write, and execute access to everyone on the system for that symbolic link. While symbolic links themselves don't directly store data, they point to another file or directory. Therefore, these permissions effectively dictate who can interact with the target of the symbolic link.
Key considerations:
- Security Risk: Granting
rwxrwxrwx(often called "777" in octal notation) to regular files or directories is generally considered a significant security risk, especially in multi-user environments. It means any user can read, modify, or delete the file, or if it's a directory, add/remove files from it. - Symbolic Links: While symbolic links pointing to sensitive files should still be protected, the permissions on the symbolic link itself determine who can access the link, not necessarily who can modify the target file. The actual permissions on the target file also matter greatly. However, if a symbolic link itself is writable by others, it could potentially be altered to point to a different, malicious location.
- Use Cases: Such broad permissions are rarely advisable for critical system files or sensitive data. They might be temporarily set during development or troubleshooting, or for files/directories that truly need to be globally accessible and editable, such as certain temporary directories or shared resources.
Understanding these permission strings is fundamental for managing files and directories securely and efficiently in Linux and Unix environments.
