From 521b3d79fc9bec80c4adfdb4ab8ed8d0d284fa62 Mon Sep 17 00:00:00 2001
From: Shimun <shimun@shimun.net>
Date: Tue, 29 Oct 2019 14:24:08 +0100
Subject: [PATCH] first commit

---
 Cargo.toml  |  24 +++++++++++
 src/lib.rs  | 115 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/main.rs |  29 +++++++++++++
 3 files changed, 168 insertions(+)
 create mode 100644 Cargo.toml
 create mode 100644 src/lib.rs
 create mode 100644 src/main.rs

diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..86ff245
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,24 @@
+[package]
+name = "fido2_pam"
+version = "0.1.0"
+authors = ["shimun <shimun@shimun.net>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[lib]
+name = "pam_fido2"
+path = "src/lib.rs"
+crate-type = ["cdylib"]
+
+[[bin]]
+name = "fido2-pam-credential"
+path = "src/main.rs"
+
+
+[dependencies]
+ctap = "0.1.0"
+pamsm = "0.2.0"
+regex = "1.3.1"
+rand = "0.7.2"
+hex = "0.4.0"
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..665eedf
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,115 @@
+#[macro_use]
+extern crate pamsm;
+
+use ctap;
+use pamsm::{Pam, PamError, PamFlag, PamServiceModule};
+use rand::Rng;
+use regex::Regex;
+use std::fs::File;
+use std::io::{self, prelude::*, BufReader};
+use std::time::{Duration, SystemTime};
+
+struct PamFido2;
+
+struct Settings {
+    pub device_timeout: Duration,
+    pub user_credentials: Vec<(String, String)>,
+}
+
+impl Default for Settings {
+    fn default() -> Self {
+        Settings {
+   device_timeout: Duration::from_secs(15),
+   user_credentials: vec![("091566e43802c5a29971c1e08d7865d959af862cc28af22dacf413ac26b90f6dea7d1ac491d9d3712c63f7b8d6cfadf86d057d099d382246dbe9c87f133ed167881b65030000".into(),".*".into())],
+  }
+    }
+}
+
+impl Settings {
+    pub fn load() -> Settings {
+        let mut creds = Vec::new();
+        for path in &["./pam_fido2.conf", "/etc/pam_fido2.conf"] {
+            let file = match File::open(&path) {
+                Ok(file) => file,
+                _ => continue,
+            };
+            let reader = BufReader::new(file);
+
+            for line in reader.lines() {
+                let line = line.unwrap();
+                let mut parts = line.split(":");
+                let user = parts.by_ref().next().unwrap();
+                creds.push((user.to_string(), (&parts.collect::<Vec<_>>()[..].join(":")).to_string()));
+            }
+        }
+        Settings{
+            user_credentials: creds,
+            ..Default::default()
+        }
+    }
+
+    pub fn get_credential(&self, user: &str) -> Option<ctap::FidoCredential> {
+        for (cred, pattern) in self.user_credentials.iter() {
+            let re = Regex::new(&pattern).expect(&["Invalid regex pattern:", &pattern].join(" "));
+            if re.is_match(user) {
+                let mut parts = cred.split(":");
+                //TODO: use expect
+                let id = parts.by_ref().next().unwrap();
+                let key = parts.by_ref().next().unwrap();
+                return Some(ctap::FidoCredential {
+                    id: hex::decode(id).unwrap(),
+                    public_key: hex::decode(key).unwrap(),
+                    rp_id: "pam".into(),
+                });
+            }
+        }
+        None
+    }
+}
+
+impl PamFido2 {
+    fn settings(&self) -> Settings {
+        Settings::load()
+    }
+}
+
+impl PamServiceModule for PamFido2 {
+    fn authenticate(self: &Self, pamh: Pam, _: PamFlag, _args: Vec<String>) -> PamError {
+        let settings = self.settings();
+        let begin = SystemTime::now();
+        let mut device = loop {
+            if let Ok(devices) = ctap::get_devices() {
+                if let Some(dev) = devices.first() {
+                    break ctap::FidoDevice::new(dev).unwrap();
+                }
+            }
+            if begin.elapsed().unwrap() > settings.device_timeout {
+                return PamError::AUTH_ERR;
+            }
+        };
+        let challenge = rand::thread_rng().gen::<[u8; 32]>();
+        let credential = settings
+            .get_credential(
+                &pamh
+                    .get_cached_user()
+                    .ok()
+                    .map(|name| name.unwrap().to_str().unwrap().to_string())
+                    .expect("Faied to get username"),
+            )
+            .expect("Couldn't find credential for user");
+        match device.get_assertion(&credential, &challenge) {
+            Ok(true) => PamError::SUCCESS,
+            _ => PamError::AUTH_ERR,
+        }
+    }
+}
+
+pamsm_init!(Box::new(PamFido2));
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn it_works() {
+        assert_eq!(2 + 2, 4);
+    }
+}
diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..e42b547
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,29 @@
+use ctap;
+use hex;
+use std::env::args;
+use std::error::Error;
+fn main() -> Result<(), ctap::FidoError> {
+    let user = args()
+        .skip(1)
+        .next()
+        .expect("Please supply username at index 0");
+    let devices = ctap::get_devices()?;
+    let device_info = &devices[0];
+    let mut device = ctap::FidoDevice::new(device_info)?;
+    let rp_id = "pam";
+    let user_id = [0];
+    let user_name = "pam";
+    let client_data_hash = [0; 32];
+    let cred = device.make_credential(rp_id, &user_id, user_name, &client_data_hash)?;
+
+    println!(
+        "{}",
+        &[
+            &user,
+            &hex::encode(&cred.id)[..],
+            &hex::encode(&cred.public_key)[..]
+        ]
+        .join(":")
+    );
+    Ok(())
+}