check protocol version before agent communication

5 files changed, 60 insertions, 0 deletions

diff --git a/src/bin/rbw-agent/actions.rs b/src/bin/rbw-agent/actions.rs
index 8823424..52c34fa 100644
--- a/src/bin/rbw-agent/actions.rs
+++ b/src/bin/rbw-agent/actions.rs
@@ -256,6 +256,16 @@ pub async fn encrypt(
     Ok(())
 }
 
+pub async fn version(sock: &mut crate::sock::Sock) -> anyhow::Result<()> {
+    sock.send(&rbw::protocol::Response::Version {
+        version: rbw::protocol::VERSION,
+    })
+    .await
+    .context("failed to send response")?;
+
+    Ok(())
+}
+
 async fn respond_ack(sock: &mut crate::sock::Sock) -> anyhow::Result<()> {
     sock.send(&rbw::protocol::Response::Ack)
         .await
diff --git a/src/bin/rbw-agent/agent.rs b/src/bin/rbw-agent/agent.rs
index 9021569..72d6077 100644
--- a/src/bin/rbw-agent/agent.rs
+++ b/src/bin/rbw-agent/agent.rs
@@ -156,6 +156,10 @@ async fn handle_request(
             true
         }
         rbw::protocol::Action::Quit => std::process::exit(0),
+        rbw::protocol::Action::Version => {
+            crate::actions::version(sock).await?;
+            true
+        }
     };
 
     if set_timeout {
diff --git a/src/bin/rbw/actions.rs b/src/bin/rbw/actions.rs
index 273b038..399b7f3 100644
--- a/src/bin/rbw/actions.rs
+++ b/src/bin/rbw/actions.rs
@@ -82,6 +82,24 @@ pub fn encrypt(plaintext: &str) -> anyhow::Result<String> {
     }
 }
 
+pub fn version() -> anyhow::Result<u32> {
+    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::Version,
+    })?;
+
+    let res = sock.recv()?;
+    match res {
+        rbw::protocol::Response::Version { version } => Ok(version),
+        rbw::protocol::Response::Error { error } => {
+            Err(anyhow::anyhow!("failed to get version: {}", error))
+        }
+        _ => Err(anyhow::anyhow!("unexpected message: {:?}", res)),
+    }
+}
+
 fn simple_action(
     action: rbw::protocol::Action,
     desc: &str,
diff --git a/src/bin/rbw/commands.rs b/src/bin/rbw/commands.rs
index 6c9d18c..b29987d 100644
--- a/src/bin/rbw/commands.rs
+++ b/src/bin/rbw/commands.rs
@@ -493,6 +493,30 @@ pub fn stop_agent() -> anyhow::Result<()> {
 }
 
 fn ensure_agent() -> anyhow::Result<()> {
+    ensure_agent_once()?;
+    let version = crate::actions::version()?;
+    if version != rbw::protocol::VERSION {
+        log::debug!(
+            "client protocol version is {} but agent protocol version is {}",
+            rbw::protocol::VERSION,
+            version
+        );
+        crate::actions::quit()?;
+        ensure_agent_once()?;
+        let version = crate::actions::version()?;
+        if version != rbw::protocol::VERSION {
+            crate::actions::quit()?;
+            return Err(anyhow::anyhow!(
+                "incompatible protocol versions: client ({}), agent ({})",
+                rbw::protocol::VERSION,
+                version
+            ));
+        }
+    }
+    Ok(())
+}
+
+fn ensure_agent_once() -> anyhow::Result<()> {
     let agent_path = std::env::var("RBW_AGENT");
     let agent_path = agent_path
         .as_ref()
diff --git a/src/protocol.rs b/src/protocol.rs
index de8833c..2ef99cd 100644
--- a/src/protocol.rs
+++ b/src/protocol.rs
@@ -1,3 +1,5 @@
+pub const VERSION: u32 = 1;
+
 #[derive(serde::Serialize, serde::Deserialize, Debug)]
 pub struct Request {
     pub tty: Option<String>,
@@ -14,6 +16,7 @@ pub enum Action {
     Decrypt { cipherstring: String },
     Encrypt { plaintext: String },
     Quit,
+    Version,
 }
 
 #[derive(serde::Serialize, serde::Deserialize, Debug)]
@@ -23,4 +26,5 @@ pub enum Response {
     Error { error: String },
     Decrypt { plaintext: String },
     Encrypt { cipherstring: String },
+    Version { version: u32 },
 }