start switching crypto implementations

src-tauri/src/credentials.rs

@@ -2,6 +2,25 @@ use std::fmt::{self, Formatter};
 use std::time::{SystemTime, UNIX_EPOCH};
 
 use aws_smithy_types::date_time::{DateTime, Format};
+use argon2::{
+    Argon2,
+    Algorithm,
+    Version,
+    ParamsBuilder,
+    password_hash::rand_core::{RngCore, OsRng},
+};
+use chacha20poly1305::{
+    XChaCha20Poly1305,
+    XNonce,
+    aead::{
+        Aead,
+        AeadCore,
+        Key,
+        KeyInit,
+        Error as AeadError,
+        generic_array::GenericArray,
+    },
+};
 use serde::{
     Serialize,
     Deserialize,
@@ -10,12 +29,7 @@ use serde::{
 };
 use serde::de::{self, Visitor};
 use sqlx::SqlitePool;
-use sodiumoxide::crypto::{
-        pwhash,
-        pwhash::Salt, 
-        secretbox, 
-        secretbox::{Nonce, Key}
-};
+
 
 use crate::errors::*;
 
@@ -76,8 +90,8 @@ impl Session {
 pub struct LockedCredentials {
     pub access_key_id: String,
     pub secret_key_enc: Vec<u8>,
-    pub salt: Salt,
-    pub nonce: Nonce,
+    pub salt: [u8; 32],
+    pub nonce: XNonce,
 }
 
 impl LockedCredentials {
@@ -97,10 +111,8 @@ impl LockedCredentials {
     }
 
     pub fn decrypt(&self, passphrase: &str) -> Result<BaseCredentials, UnlockError> {
-        let mut key_buf = [0; secretbox::KEYBYTES];
-        // pretty sure this only fails if we're out of memory
-        pwhash::derive_key_interactive(&mut key_buf, passphrase.as_bytes(), &self.salt).unwrap();
-        let decrypted = secretbox::open(&self.secret_key_enc, &self.nonce, &Key(key_buf))
+        let crypto = Crypto::new(passphrase, &self.salt);
+        let decrypted = crypto.decrypt(&self.nonce, &self.secret_key_enc)
             .map_err(|_| UnlockError::BadPassphrase)?;
         let secret_access_key = String::from_utf8(decrypted)
             .map_err(|_| UnlockError::InvalidUtf8)?;
@@ -122,21 +134,18 @@ pub struct BaseCredentials {
 }
 
 impl BaseCredentials {
-    pub fn encrypt(&self, passphrase: &str) -> LockedCredentials {
-        let salt = pwhash::gen_salt();
-        let mut key_buf = [0; secretbox::KEYBYTES];
-        pwhash::derive_key_interactive(&mut key_buf, passphrase.as_bytes(), &salt).unwrap();
-        let key = Key(key_buf);
-        let nonce = secretbox::gen_nonce();
+    pub fn encrypt(&self, passphrase: &str) -> Result<CryptoError, LockedCredentials> {
+        let salt = Crypto::salt();
+        let crypto = Crypto::new(passphrase, &salt)?;
+        let (nonce, secret_key_enc) = crypto.encrypt(self.secret_access_key.as_bytes());
 
-        let secret_key_enc = secretbox::seal(self.secret_access_key.as_bytes(), &nonce, &key);
-
-        LockedCredentials {
+        let locked = LockedCredentials {
             access_key_id: self.access_key_id.clone(),
             secret_key_enc,
             salt,
             nonce,
-        }
+        };
+        Ok(locked)
     }
 }
 
@@ -241,4 +250,60 @@ fn deserialize_expiration<'de, D>(deserializer: D) -> Result<DateTime, D::Error>
 where D: Deserializer<'de>
 {
     deserializer.deserialize_str(DateTimeVisitor)
-}
+}
+
+
+struct Crypto {
+    cipher: XChaCha20Poly1305,
+}
+
+impl Crypto {
+    /// Argon2 params rationale:
+    ///
+    /// m_cost is measured in KiB, so 128 * 1024 gives us 128MiB.
+    /// This should roughly double the memory usage of the application
+    /// while deriving the key.
+    ///
+    /// p_cost is irrelevant since (at present) there isn't any parallelism
+    /// implemented, so we leave it at 1.
+    ///
+    /// With the above m_cost, t_cost = 8 results in about 800ms to derive
+    /// a key on my (somewhat older) CPU. This is probably overkill, but
+    /// given that it should only have to happen ~once a day for most 
+    /// usage, it should be acceptable.
+    fn new(passphrase: &str, salt: &[u8]) -> argon2::Result<Crypto> {
+        let params = ParamsBuilder::new()
+            .m_cost(128 * 1024)
+            .p_cost(1)
+            .t_cost(8)
+            .build()
+            .unwrap(); // only errors if the given params are invalid
+
+        let hasher = Argon2::new(
+            Algorithm::Argon2id,
+            Version::V0x13,
+            params,
+        );
+
+        let mut key = [0; 32];
+        hasher.hash_password_into(passphrase.as_bytes(), &salt, &mut key)?;
+        let cipher = XChaCha20Poly1305::new(GenericArray::from_slice(&key));
+        Ok(Crypto { cipher })
+    }
+
+    fn salt() -> [u8; 32] {
+        let mut salt = [0; 32];
+        OsRng.fill_bytes(&mut salt);
+        salt
+    }
+
+    fn encrypt(&self, data: &[u8]) -> Result<(XNonce, Vec<u8>), AeadError> {
+        let nonce = XChaCha20Poly1305::generate_nonce(&mut OsRng);
+        let ciphertext = self.cipher.encrypt(&nonce, data)?;
+        Ok((nonce, ciphertext))
+    }
+
+    fn decrypt(&self, nonce: &XNonce, data: &[u8]) -> Result<Vec<u8>, AeadError> {
+        self.cipher.decrypt(nonce, data)
+    }
+}