libnss-rs

Rust bindings for creating libnss modules.

Currently supports the following databases: - passwd - shadow - group - hosts

Getting started

• Create a new library

bash cargo new nss_example --lib

• Change library type to cdylib in your Cargo.toml

yaml [lib] name = "nss_example" crate-type = [ "cdylib" ] * NOTE * The name of the crate itself is not important, however the library itself must follow the nss_xxx pattern.

• Add libnss to your Cargo.toml

yaml [dependencies] libc = "0.2.0" lazy_static = "1.3.0" paste = "0.1" libnss = "0.1.0"

• Add the following to your src/main.rs

```rust extern crate libc;

[macro_use]

extern crate lazy_static;

[macro_use]

extern crate libnss; ```

• Implement a passwd database

```rust use libnss::passwd::{PasswdHooks, Passwd};

struct ExamplePasswd; libnsspasswdhooks!(example, ExamplePasswd); It is important that the first param oflibnsspasswdhooksis the name of your final librarylibnss_example.so.2```

````rust impl PasswdHooks for HardcodedPasswd { fn getallentries() -> Vec { vec![ Passwd { name: "test".tostring(), passwd: "x".tostring(), uid: 1005, gid: 1005, gecos: "Test Account".tostring(), dir: "/home/test".tostring(), shell: "/bin/bash".to_string(), } ] }

fn get_entry_by_uid(uid: libc::uid_t) -> Option<Passwd> {
    if uid == 1005 {
        return Some(Passwd {
            name: "test".to_string(),
            passwd: "x".to_string(),
            uid: 1005,
            gid: 1005,
            gecos: "Test Account".to_string(),
            dir: "/home/test".to_string(),
            shell: "/bin/bash".to_string(),
        });
    }

    None
}

fn get_entry_by_name(name: String) -> Option<Passwd> {
    if name == "test" {
        return Some(Passwd {
            name: "test".to_string(),
            passwd: "x".to_string(),
            uid: 1005,
            gid: 1005,
            gecos: "Test Account".to_string(),
            dir: "/home/test".to_string(),
            shell: "/bin/bash".to_string(),
        });
    }

    None
}

} ````

• Install the library

bash cd target/release cp libnss_example.so libnss_example.so.2 sudo install -m 0644 libnss_example.so.2 /lib sudo /sbin/ldconfig -n /lib /usr/lib

• Enable your nss module in /etc/nsswitch.conf

eg: passwd: example files systemd

The name in here must follow the final library name libnss_example.so.2

• Look at the examples for more information