From 777b810db4675305854c373dcd57aedc40061e5d Mon Sep 17 00:00:00 2001
From: Jesse Luehrs <doy@tozt.net>
Date: Sat, 18 Apr 2020 01:28:48 -0400
Subject: add encryption to the agent protocol

---
 src/bin/rbw-agent/actions.rs | 33 +++++++++++++++++++++++++++++
 src/bin/rbw-agent/agent.rs   |  4 ++++
 src/bin/rbw/actions.rs       | 20 ++++++++++++++++++
 src/cipherstring.rs          | 49 ++++++++++++++++++++++++++++++++++++++++++++
 src/protocol.rs              |  2 ++
 5 files changed, 108 insertions(+)

diff --git a/src/bin/rbw-agent/actions.rs b/src/bin/rbw-agent/actions.rs
index 2cb012c..7289a25 100644
--- a/src/bin/rbw-agent/actions.rs
+++ b/src/bin/rbw-agent/actions.rs
@@ -192,6 +192,28 @@ pub async fn decrypt(
     Ok(())
 }
 
+pub async fn encrypt(
+    sock: &mut crate::sock::Sock,
+    state: std::sync::Arc<tokio::sync::RwLock<crate::agent::State>>,
+    plaintext: &str,
+) -> anyhow::Result<()> {
+    let state = state.read().await;
+    let keys = if let Some(keys) = &state.priv_key {
+        keys
+    } else {
+        return Err(anyhow::anyhow!(
+            "failed to find encryption keys in in-memory state"
+        ));
+    };
+    let cipherstring =
+        rbw::cipherstring::CipherString::encrypt(keys, plaintext.as_bytes())
+            .context("failed to encrypt plaintext secret")?;
+
+    respond_encrypt(sock, cipherstring.to_string()).await?;
+
+    Ok(())
+}
+
 async fn respond_ack(sock: &mut crate::sock::Sock) -> anyhow::Result<()> {
     sock.send(&rbw::protocol::Response::Ack)
         .await
@@ -211,6 +233,17 @@ async fn respond_decrypt(
     Ok(())
 }
 
+async fn respond_encrypt(
+    sock: &mut crate::sock::Sock,
+    cipherstring: String,
+) -> anyhow::Result<()> {
+    sock.send(&rbw::protocol::Response::Encrypt { cipherstring })
+        .await
+        .context("failed to send response")?;
+
+    Ok(())
+}
+
 async fn config_email() -> anyhow::Result<String> {
     let config = rbw::config::Config::load_async()
         .await
diff --git a/src/bin/rbw-agent/agent.rs b/src/bin/rbw-agent/agent.rs
index 21600c3..e80e1c6 100644
--- a/src/bin/rbw-agent/agent.rs
+++ b/src/bin/rbw-agent/agent.rs
@@ -142,6 +142,10 @@ async fn handle_request(
                 .await?;
             true
         }
+        rbw::protocol::Action::Encrypt { plaintext } => {
+            crate::actions::encrypt(sock, state.clone(), &plaintext).await?;
+            true
+        }
         rbw::protocol::Action::Quit => std::process::exit(0),
     };
 
diff --git a/src/bin/rbw/actions.rs b/src/bin/rbw/actions.rs
index 5951185..b3a9f1b 100644
--- a/src/bin/rbw/actions.rs
+++ b/src/bin/rbw/actions.rs
@@ -55,6 +55,26 @@ pub fn decrypt(cipherstring: &str) -> anyhow::Result<String> {
     }
 }
 
+pub fn encrypt(plaintext: &str) -> anyhow::Result<String> {
+    let mut sock = crate::sock::Sock::connect()
+        .context("failed to connect to rbw-agent")?;
+    sock.send(&rbw::protocol::Request {
+        tty: std::env::var("TTY").ok(),
+        action: rbw::protocol::Action::Encrypt {
+            plaintext: plaintext.to_string(),
+        },
+    })?;
+
+    let res = sock.recv()?;
+    match res {
+        rbw::protocol::Response::Encrypt { cipherstring } => Ok(cipherstring),
+        rbw::protocol::Response::Error { error } => {
+            Err(anyhow::anyhow!("failed to encrypt: {}", error))
+        }
+        _ => Err(anyhow::anyhow!("unexpected message: {:?}", res)),
+    }
+}
+
 fn simple_action(
     action: rbw::protocol::Action,
     desc: &str,
diff --git a/src/cipherstring.rs b/src/cipherstring.rs
index 9f2c261..2398b07 100644
--- a/src/cipherstring.rs
+++ b/src/cipherstring.rs
@@ -2,6 +2,7 @@ use crate::prelude::*;
 
 use block_modes::BlockMode as _;
 use hmac::Mac as _;
+use rand::RngCore as _;
 
 pub struct CipherString {
     ty: u8,
@@ -51,6 +52,34 @@ impl CipherString {
         })
     }
 
+    pub fn encrypt(
+        keys: &crate::locked::Keys,
+        plaintext: &[u8],
+    ) -> Result<Self> {
+        let iv = random_iv();
+
+        let cipher = block_modes::Cbc::<
+            aes::Aes256,
+            block_modes::block_padding::Pkcs7,
+        >::new_var(keys.enc_key(), &iv)
+        .context(crate::error::CreateBlockMode)?;
+        let ciphertext = cipher.encrypt_vec(plaintext);
+
+        let mut digest =
+            hmac::Hmac::<sha2::Sha256>::new_varkey(keys.mac_key())
+                .map_err(|_| Error::InvalidMacKey)?;
+        digest.input(&iv);
+        digest.input(&ciphertext);
+        let mac = digest.result().code().to_vec();
+
+        Ok(Self {
+            ty: 2,
+            iv,
+            ciphertext,
+            mac: Some(mac),
+        })
+    }
+
     pub fn decrypt(&self, keys: &crate::locked::Keys) -> Result<Vec<u8>> {
         let cipher = self.decrypt_common(keys)?;
         cipher
@@ -102,6 +131,19 @@ impl CipherString {
     }
 }
 
+impl std::fmt::Display for CipherString {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        let iv = base64::encode(&self.iv);
+        let ciphertext = base64::encode(&self.ciphertext);
+        if let Some(mac) = &self.mac {
+            let mac = base64::encode(&mac);
+            write!(f, "{}.{}|{}|{}", self.ty, iv, ciphertext, mac)
+        } else {
+            write!(f, "{}.{}|{}", self.ty, iv, ciphertext)
+        }
+    }
+}
+
 fn macs_equal(mac1: &[u8], mac2: &[u8], mac_key: &[u8]) -> Result<bool> {
     let mut digest = hmac::Hmac::<sha2::Sha256>::new_varkey(mac_key)
         .map_err(|_| Error::InvalidMacKey)?;
@@ -115,3 +157,10 @@ fn macs_equal(mac1: &[u8], mac2: &[u8], mac_key: &[u8]) -> Result<bool> {
 
     Ok(hmac1 == hmac2)
 }
+
+fn random_iv() -> Vec<u8> {
+    let mut iv = vec![0_u8; 16];
+    let mut rng = rand::thread_rng();
+    rng.fill_bytes(&mut iv);
+    iv
+}
diff --git a/src/protocol.rs b/src/protocol.rs
index 8d7cd69..5d476ca 100644
--- a/src/protocol.rs
+++ b/src/protocol.rs
@@ -12,6 +12,7 @@ pub enum Action {
     Lock,
     Sync,
     Decrypt { cipherstring: String },
+    Encrypt { plaintext: String },
     // add
     // update
     // remove
@@ -24,4 +25,5 @@ pub enum Response {
     Ack,
     Error { error: String },
     Decrypt { plaintext: String },
+    Encrypt { cipherstring: String },
 }
-- 
cgit v1.2.3-54-g00ecf