initial commit

sasl/.gitignore

@@ -0,0 +1,2 @@
+target
+Cargo.lock

sasl/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "sasl"
+version = "0.1.0"
+authors = ["lumi <lumi@pew.im>"]
+
+[dependencies]
+openssl = "0.9.7"
+base64 = "0.4.0"

sasl/src/error.rs

@@ -0,0 +1,13 @@
+use openssl::error::ErrorStack;
+
+#[derive(Debug)]
+pub enum Error {
+    OpenSslErrorStack(ErrorStack),
+    SaslError(String),
+}
+
+impl From<ErrorStack> for Error {
+    fn from(err: ErrorStack) -> Error {
+        Error::OpenSslErrorStack(err)
+    }
+}

sasl/src/lib.rs

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+//! Provides the `SaslMechanism` trait and some implementations.
+
+extern crate base64;
+extern crate openssl;
+
+pub mod error;
+
+/// A struct containing SASL credentials.
+pub struct SaslCredentials {
+    pub username: String,
+    pub secret: SaslSecret,
+    pub channel_binding: Option<Vec<u8>>,
+}
+
+/// Represents a SASL secret, like a password.
+pub enum SaslSecret {
+    /// No extra data needed.
+    None,
+    /// Password required.
+    Password(String),
+}
+
+pub trait SaslMechanism {
+    /// The name of the mechanism.
+    fn name(&self) -> &str;
+
+    /// Creates this mechanism from `SaslCredentials`.
+    fn from_credentials(credentials: SaslCredentials) -> Result<Self, String>
+    where
+        Self: Sized;
+
+    /// Provides initial payload of the SASL mechanism.
+    fn initial(&mut self) -> Result<Vec<u8>, String> {
+        Ok(Vec::new())
+    }
+
+    /// Creates a response to the SASL challenge.
+    fn response(&mut self, _challenge: &[u8]) -> Result<Vec<u8>, String> {
+        Ok(Vec::new())
+    }
+
+    /// Verifies the server success response, if there is one.
+    fn success(&mut self, _data: &[u8]) -> Result<(), String> {
+        Ok(())
+    }
+}
+
+pub mod mechanisms;

sasl/src/mechanisms/anonymous.rs

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+//! Provides the SASL "ANONYMOUS" mechanism.
+
+use SaslCredentials;
+use SaslMechanism;
+use SaslSecret;
+
+pub struct Anonymous;
+
+impl Anonymous {
+    pub fn new() -> Anonymous {
+        Anonymous
+    }
+}
+
+impl SaslMechanism for Anonymous {
+    fn name(&self) -> &str {
+        "ANONYMOUS"
+    }
+
+    fn from_credentials(credentials: SaslCredentials) -> Result<Anonymous, String> {
+        if let SaslSecret::None = credentials.secret {
+            Ok(Anonymous)
+        } else {
+            Err("the anonymous sasl mechanism requires no credentials".to_owned())
+        }
+    }
+}

sasl/src/mechanisms/mod.rs

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+///! Provides a few SASL mechanisms.
+mod anonymous;
+mod plain;
+mod scram;
+
+pub use self::anonymous::Anonymous;
+pub use self::plain::Plain;
+pub use self::scram::{Scram, ScramProvider, Sha1, Sha256};

sasl/src/mechanisms/plain.rs

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+//! Provides the SASL "PLAIN" mechanism.
+
+use SaslCredentials;
+use SaslMechanism;
+use SaslSecret;
+
+pub struct Plain {
+    username: String,
+    password: String,
+}
+
+impl Plain {
+    pub fn new<N: Into<String>, P: Into<String>>(username: N, password: P) -> Plain {
+        Plain {
+            username: username.into(),
+            password: password.into(),
+        }
+    }
+}
+
+impl SaslMechanism for Plain {
+    fn name(&self) -> &str {
+        "PLAIN"
+    }
+
+    fn from_credentials(credentials: SaslCredentials) -> Result<Plain, String> {
+        if let SaslSecret::Password(password) = credentials.secret {
+            Ok(Plain::new(credentials.username, password))
+        } else {
+            Err("PLAIN requires a password".to_owned())
+        }
+    }
+
+    fn initial(&mut self) -> Result<Vec<u8>, String> {
+        let mut auth = Vec::new();
+        auth.push(0);
+        auth.extend(self.username.bytes());
+        auth.push(0);
+        auth.extend(self.password.bytes());
+        Ok(auth)
+    }
+}

sasl/src/mechanisms/scram.rs

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+//! Provides the SASL "SCRAM-*" mechanisms and a way to implement more.
+
+use base64;
+
+use SaslCredentials;
+use SaslMechanism;
+use SaslSecret;
+
+use error::Error;
+
+use openssl::error::ErrorStack;
+use openssl::hash::hash;
+use openssl::hash::MessageDigest;
+use openssl::pkcs5::pbkdf2_hmac;
+use openssl::pkey::PKey;
+use openssl::rand::rand_bytes;
+use openssl::sign::Signer;
+
+use std::marker::PhantomData;
+
+use std::collections::HashMap;
+
+use std::string::FromUtf8Error;
+
+#[cfg(test)]
+#[test]
+fn xor_works() {
+    assert_eq!(
+        xor(
+            &[135, 94, 53, 134, 73, 233, 140, 221, 150, 12, 96, 111, 54, 66, 11, 76],
+            &[163, 9, 122, 180, 107, 44, 22, 252, 248, 134, 112, 82, 84, 122, 56, 209]
+        ),
+        &[36, 87, 79, 50, 34, 197, 154, 33, 110, 138, 16, 61, 98, 56, 51, 157]
+    );
+}
+
+fn xor(a: &[u8], b: &[u8]) -> Vec<u8> {
+    assert_eq!(a.len(), b.len());
+    let mut ret = Vec::with_capacity(a.len());
+    for (a, b) in a.into_iter().zip(b) {
+        ret.push(a ^ b);
+    }
+    ret
+}
+
+fn parse_frame(frame: &[u8]) -> Result<HashMap<String, String>, FromUtf8Error> {
+    let inner = String::from_utf8(frame.to_owned())?;
+    let mut ret = HashMap::new();
+    for s in inner.split(',') {
+        let mut tmp = s.splitn(2, '=');
+        let key = tmp.next();
+        let val = tmp.next();
+        match (key, val) {
+            (Some(k), Some(v)) => {
+                ret.insert(k.to_owned(), v.to_owned());
+            }
+            _ => (),
+        }
+    }
+    Ok(ret)
+}
+
+fn generate_nonce() -> Result<String, ErrorStack> {
+    let mut data = vec![0; 32];
+    rand_bytes(&mut data)?;
+    Ok(base64::encode(&data))
+}
+
+pub trait ScramProvider {
+    fn name() -> &'static str;
+    fn hash(data: &[u8]) -> Vec<u8>;
+    fn hmac(data: &[u8], key: &[u8]) -> Vec<u8>;
+    fn derive(data: &[u8], salt: &[u8], iterations: usize) -> Vec<u8>;
+}
+
+pub struct Sha1;
+
+impl ScramProvider for Sha1 {
+    // TODO: look at all these unwraps
+    fn name() -> &'static str {
+        "SHA-1"
+    }
+
+    fn hash(data: &[u8]) -> Vec<u8> {
+        hash(MessageDigest::sha1(), data).unwrap()
+    }
+
+    fn hmac(data: &[u8], key: &[u8]) -> Vec<u8> {
+        let pkey = PKey::hmac(key).unwrap();
+        let mut signer = Signer::new(MessageDigest::sha1(), &pkey).unwrap();
+        signer.update(data).unwrap();
+        signer.finish().unwrap()
+    }
+
+    fn derive(data: &[u8], salt: &[u8], iterations: usize) -> Vec<u8> {
+        let mut result = vec![0; 20];
+        pbkdf2_hmac(data, salt, iterations, MessageDigest::sha1(), &mut result).unwrap();
+        result
+    }
+}
+
+pub struct Sha256;
+
+impl ScramProvider for Sha256 {
+    // TODO: look at all these unwraps
+    fn name() -> &'static str {
+        "SHA-256"
+    }
+
+    fn hash(data: &[u8]) -> Vec<u8> {
+        hash(MessageDigest::sha256(), data).unwrap()
+    }
+
+    fn hmac(data: &[u8], key: &[u8]) -> Vec<u8> {
+        let pkey = PKey::hmac(key).unwrap();
+        let mut signer = Signer::new(MessageDigest::sha256(), &pkey).unwrap();
+        signer.update(data).unwrap();
+        signer.finish().unwrap()
+    }
+
+    fn derive(data: &[u8], salt: &[u8], iterations: usize) -> Vec<u8> {
+        let mut result = vec![0; 32];
+        pbkdf2_hmac(data, salt, iterations, MessageDigest::sha256(), &mut result).unwrap();
+        result
+    }
+}
+
+enum ScramState {
+    Init,
+    SentInitialMessage {
+        initial_message: Vec<u8>,
+        gs2_header: Vec<u8>,
+    },
+    GotServerData {
+        server_signature: Vec<u8>,
+    },
+}
+
+pub struct Scram<S: ScramProvider> {
+    name: String,
+    username: String,
+    password: String,
+    client_nonce: String,
+    state: ScramState,
+    channel_binding: Option<Vec<u8>>,
+    _marker: PhantomData<S>,
+}
+
+impl<S: ScramProvider> Scram<S> {
+    pub fn new<N: Into<String>, P: Into<String>>(
+        username: N,
+        password: P,
+    ) -> Result<Scram<S>, Error> {
+        Ok(Scram {
+            name: format!("SCRAM-{}", S::name()),
+            username: username.into(),
+            password: password.into(),
+            client_nonce: generate_nonce()?,
+            state: ScramState::Init,
+            channel_binding: None,
+            _marker: PhantomData,
+        })
+    }
+
+    pub fn new_with_nonce<N: Into<String>, P: Into<String>>(
+        username: N,
+        password: P,
+        nonce: String,
+    ) -> Scram<S> {
+        Scram {
+            name: format!("SCRAM-{}", S::name()),
+            username: username.into(),
+            password: password.into(),
+            client_nonce: nonce,
+            state: ScramState::Init,
+            channel_binding: None,
+            _marker: PhantomData,
+        }
+    }
+
+    pub fn new_with_channel_binding<N: Into<String>, P: Into<String>>(
+        username: N,
+        password: P,
+        channel_binding: Vec<u8>,
+    ) -> Result<Scram<S>, Error> {
+        Ok(Scram {
+            name: format!("SCRAM-{}-PLUS", S::name()),
+            username: username.into(),
+            password: password.into(),
+            client_nonce: generate_nonce()?,
+            state: ScramState::Init,
+            channel_binding: Some(channel_binding),
+            _marker: PhantomData,
+        })
+    }
+}
+
+impl<S: ScramProvider> SaslMechanism for Scram<S> {
+    fn name(&self) -> &str {
+        // TODO: this is quite the workaround…
+        &self.name
+    }
+
+    fn from_credentials(credentials: SaslCredentials) -> Result<Scram<S>, String> {
+        if let SaslSecret::Password(password) = credentials.secret {
+            if let Some(binding) = credentials.channel_binding {
+                Scram::new_with_channel_binding(credentials.username, password, binding)
+                    .map_err(|_| "can't generate nonce".to_owned())
+            } else {
+                Scram::new(credentials.username, password)
+                    .map_err(|_| "can't generate nonce".to_owned())
+            }
+        } else {
+            Err("SCRAM requires a password".to_owned())
+        }
+    }
+
+    fn initial(&mut self) -> Result<Vec<u8>, String> {
+        let mut gs2_header = Vec::new();
+        if let Some(_) = self.channel_binding {
+            gs2_header.extend(b"p=tls-unique,,");
+        } else {
+            gs2_header.extend(b"n,,");
+        }
+        let mut bare = Vec::new();
+        bare.extend(b"n=");
+        bare.extend(self.username.bytes());
+        bare.extend(b",r=");
+        bare.extend(self.client_nonce.bytes());
+        let mut data = Vec::new();
+        data.extend(&gs2_header);
+        data.extend(bare.clone());
+        self.state = ScramState::SentInitialMessage {
+            initial_message: bare,
+            gs2_header: gs2_header,
+        };
+        Ok(data)
+    }
+
+    fn response(&mut self, challenge: &[u8]) -> Result<Vec<u8>, String> {
+        let next_state;
+        let ret;
+        match self.state {
+            ScramState::SentInitialMessage {
+                ref initial_message,
+                ref gs2_header,
+            } => {
+                let frame =
+                    parse_frame(challenge).map_err(|_| "can't decode challenge".to_owned())?;
+                let server_nonce = frame.get("r");
+                let salt = frame.get("s").and_then(|v| base64::decode(v).ok());
+                let iterations = frame.get("i").and_then(|v| v.parse().ok());
+                let server_nonce = server_nonce.ok_or_else(|| "no server nonce".to_owned())?;
+                let salt = salt.ok_or_else(|| "no server salt".to_owned())?;
+                let iterations = iterations.ok_or_else(|| "no server iterations".to_owned())?;
+                // TODO: SASLprep
+                let mut client_final_message_bare = Vec::new();
+                client_final_message_bare.extend(b"c=");
+                let mut cb_data: Vec<u8> = Vec::new();
+                cb_data.extend(gs2_header);
+                if let Some(ref cb) = self.channel_binding {
+                    cb_data.extend(cb);
+                }
+                client_final_message_bare.extend(base64::encode(&cb_data).bytes());
+                client_final_message_bare.extend(b",r=");
+                client_final_message_bare.extend(server_nonce.bytes());
+                let salted_password = S::derive(self.password.as_bytes(), &salt, iterations);
+                let client_key = S::hmac(b"Client Key", &salted_password);
+                let server_key = S::hmac(b"Server Key", &salted_password);
+                let mut auth_message = Vec::new();
+                auth_message.extend(initial_message);
+                auth_message.push(b',');
+                auth_message.extend(challenge);
+                auth_message.push(b',');
+                auth_message.extend(&client_final_message_bare);
+                let stored_key = S::hash(&client_key);
+                let client_signature = S::hmac(&auth_message, &stored_key);
+                let client_proof = xor(&client_key, &client_signature);
+                let server_signature = S::hmac(&auth_message, &server_key);
+                let mut client_final_message = Vec::new();
+                client_final_message.extend(&client_final_message_bare);
+                client_final_message.extend(b",p=");
+                client_final_message.extend(base64::encode(&client_proof).bytes());
+                next_state = ScramState::GotServerData {
+                    server_signature: server_signature,
+                };
+                ret = client_final_message;
+            }
+            _ => {
+                return Err("not in the right state to receive this response".to_owned());
+            }
+        }
+        self.state = next_state;
+        Ok(ret)
+    }
+
+    fn success(&mut self, data: &[u8]) -> Result<(), String> {
+        let frame = parse_frame(data).map_err(|_| "can't decode success response".to_owned())?;
+        match self.state {
+            ScramState::GotServerData {
+                ref server_signature,
+            } => {
+                if let Some(sig) = frame.get("v").and_then(|v| base64::decode(&v).ok()) {
+                    if sig == *server_signature {
+                        Ok(())
+                    } else {
+                        Err("invalid signature in success response".to_owned())
+                    }
+                } else {
+                    Err("no signature in success response".to_owned())
+                }
+            }
+            _ => Err("not in the right state to get a success response".to_owned()),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use SaslMechanism;
+
+    use super::*;
+
+    #[test]
+    fn scram_sha1_works() {
+        // Source: https://wiki.xmpp.org/web/SASLandSCRAM-SHA-1
+        let username = "user";
+        let password = "pencil";
+        let client_nonce = "fyko+d2lbbFgONRv9qkxdawL";
+        let client_init = b"n,,n=user,r=fyko+d2lbbFgONRv9qkxdawL";
+        let server_init = b"r=fyko+d2lbbFgONRv9qkxdawL3rfcNHYJY1ZVvWVs7j,s=QSXCR+Q6sek8bf92,i=4096";
+        let client_final =
+            b"c=biws,r=fyko+d2lbbFgONRv9qkxdawL3rfcNHYJY1ZVvWVs7j,p=v0X8v3Bz2T0CJGbJQyF0X+HI4Ts=";
+        let server_final = b"v=rmF9pqV8S7suAoZWja4dJRkFsKQ=";
+        let mut mechanism =
+            Scram::<Sha1>::new_with_nonce(username, password, client_nonce.to_owned());
+        let init = mechanism.initial().unwrap();
+        assert_eq!(
+            String::from_utf8(init.clone()).unwrap(),
+            String::from_utf8(client_init[..].to_owned()).unwrap()
+        ); // depends on ordering…
+        let resp = mechanism.response(&server_init[..]).unwrap();
+        assert_eq!(
+            String::from_utf8(resp.clone()).unwrap(),
+            String::from_utf8(client_final[..].to_owned()).unwrap()
+        ); // again, depends on ordering…
+        mechanism.success(&server_final[..]).unwrap();
+    }
+
+    #[test]
+    fn scram_sha256_works() {
+        // Source: RFC 7677
+        let username = "user";
+        let password = "pencil";
+        let client_nonce = "rOprNGfwEbeRWgbNEkqO";
+        let client_init = b"n,,n=user,r=rOprNGfwEbeRWgbNEkqO";
+        let server_init = b"r=rOprNGfwEbeRWgbNEkqO%hvYDpWUa2RaTCAfuxFIlj)hNlF$k0,s=W22ZaJ0SNY7soEsUEjb6gQ==,i=4096";
+        let client_final = b"c=biws,r=rOprNGfwEbeRWgbNEkqO%hvYDpWUa2RaTCAfuxFIlj)hNlF$k0,p=dHzbZapWIk4jUhN+Ute9ytag9zjfMHgsqmmiz7AndVQ=";
+        let server_final = b"v=6rriTRBi23WpRR/wtup+mMhUZUn/dB5nLTJRsjl95G4=";
+        let mut mechanism =
+            Scram::<Sha256>::new_with_nonce(username, password, client_nonce.to_owned());
+        let init = mechanism.initial().unwrap();
+        assert_eq!(
+            String::from_utf8(init.clone()).unwrap(),
+            String::from_utf8(client_init[..].to_owned()).unwrap()
+        ); // depends on ordering…
+        let resp = mechanism.response(&server_init[..]).unwrap();
+        assert_eq!(
+            String::from_utf8(resp.clone()).unwrap(),
+            String::from_utf8(client_final[..].to_owned()).unwrap()
+        ); // again, depends on ordering…
+        mechanism.success(&server_final[..]).unwrap();
+    }
+}