Verify stored keychain SSH signatures

AGENTS.md

@@ -126,7 +126,9 @@ Roadmap items should be actionable and checkable:
   `keychain status`. `keychain init --signing-key <path>` signs recorded
   keychain ops with `ssh-keygen -Y sign` under the
   `geth.keychain.v1@geth.local` namespace and stores signatures locally.
-  Verification before accepting replicated keychain ops is still roadmap work.
+  `keychain status` verifies stored signatures with OpenSSH when public key
+  material is available. Verification before accepting replicated keychain ops
+  is still roadmap work.
 - Local CAS supports pin/unpin metadata, surfaced through `cas list`, and
   `cas cleanup` evicts unpinned blobs while retaining pinned blobs. The daemon
   can fetch CAS blobs from an imported signed peer card over Iroh when the peer

README.md

@@ -32,8 +32,8 @@ the keychain initialization/admin-key operations and signs their canonical
 payloads through `ssh-keygen -Y sign` using the
 `geth.keychain.v1@geth.local` namespace. This is the bootstrap path for
 admin/YubiKey-rooted trust. `geth keychain status` reports the number of stored
-keychain signatures; signature verification for replicated keychain ops is still
-future work.
+keychain signatures plus how many currently verify with OpenSSH; rejecting
+unsigned or invalid replicated keychain ops is still future work.
 
 The daemon can also install itself as a user service:
 

crates/geth-cli/src/lib.rs

@@ -1103,6 +1103,8 @@ fn print_response(response: ControlResponse, json: bool) -> Result<()> {
             println!("initialized: {}", status.initialized);
             println!("admin_keys: {}", status.admin_keys);
             println!("signatures: {}", status.signatures);
+            println!("verified_signatures: {}", status.verified_signatures);
+            println!("failed_signatures: {}", status.failed_signatures);
             println!("users: {}", status.users);
             println!("devices: {}", status.devices);
             println!("nodes: {}", status.nodes);

crates/geth-control/src/lib.rs

@@ -593,6 +593,8 @@ pub struct KeychainStatusResponse {
     pub initialized: bool,
     pub admin_keys: usize,
     pub signatures: usize,
+    pub verified_signatures: usize,
+    pub failed_signatures: usize,
     pub users: usize,
     pub devices: usize,
     pub nodes: usize,

crates/geth-keychain/src/lib.rs

@@ -32,6 +32,7 @@ pub struct KeychainOp {
 pub struct KeychainOpSignature {
     pub op_id: AuthOpId,
     pub signer: KeyId,
+    pub signer_public_key: String,
     pub namespace: String,
     pub signature: Vec<u8>,
     pub created_at: UnixMillis,

crates/geth-node/src/lib.rs

@@ -2890,7 +2890,7 @@ pub fn handle_request(
             }
 
             let signatures = if let Some(signing_key_path) = signing_key_path {
-                let signer =
+                let (signer, signer_public_key) =
                     keychain_signer_from_paths(&signing_key_path, admin_key_path.as_deref())?;
                 let mut signatures = Vec::new();
                 for op in &ops {
@@ -2900,6 +2900,7 @@ pub fn handle_request(
                         op,
                         &signing_key_path,
                         &signer,
+                        &signer_public_key,
                     )?);
                 }
                 signatures
@@ -2911,10 +2912,13 @@ pub fn handle_request(
         }
         ControlRequest::KeychainStatus => {
             let view = geth_keychain::reduce_keychain_ops(&load_keychain_ops(&store)?);
+            let signature_status = verify_keychain_signatures(&store, node)?;
             Ok(ControlResponse::KeychainStatus(KeychainStatusResponse {
                 initialized: view.initialized,
                 admin_keys: view.admin_keys.len(),
-                signatures: store.list_keychain_signatures()?.len(),
+                signatures: signature_status.total,
+                verified_signatures: signature_status.verified,
+                failed_signatures: signature_status.failed,
                 users: view.users.len(),
                 devices: view.devices.len(),
                 nodes: view.nodes.len(),
@@ -4021,12 +4025,15 @@ fn store_keychain_op(store: &Store, op: &KeychainOp) -> Result<(), NodeError> {
 fn keychain_signer_from_paths(
     signing_key_path: &Path,
     admin_key_path: Option<&Path>,
-) -> Result<KeyId, NodeError> {
+) -> Result<(KeyId, String), NodeError> {
     let public_key_path = admin_key_path
         .map(Path::to_path_buf)
         .unwrap_or_else(|| Path::new(&format!("{}.pub", signing_key_path.display())).to_path_buf());
     let public_key = std::fs::read_to_string(public_key_path)?;
-    Ok(KeyId::new(ssh_public_key_fingerprint(&public_key)))
+    Ok((
+        KeyId::new(ssh_public_key_fingerprint(&public_key)),
+        public_key,
+    ))
 }
 
 fn sign_keychain_op_with_ssh(
@@ -4035,6 +4042,7 @@ fn sign_keychain_op_with_ssh(
     op: &KeychainOp,
     signing_key_path: &Path,
     signer: &KeyId,
+    signer_public_key: &str,
 ) -> Result<KeychainOpSignature, NodeError> {
     geth_ssh_identity::ensure_ssh_keygen_available()?;
     let signature_dir = node.paths.home().join("keychain-signatures");
@@ -4062,6 +4070,7 @@ fn sign_keychain_op_with_ssh(
     let signature = KeychainOpSignature {
         op_id: op.id.clone(),
         signer: signer.clone(),
+        signer_public_key: signer_public_key.to_owned(),
         namespace: geth_keychain::KEYCHAIN_SIGNATURE_NAMESPACE.to_owned(),
         signature: signature_bytes,
         created_at,
@@ -4069,6 +4078,7 @@ fn sign_keychain_op_with_ssh(
     store.insert_keychain_signature(&StoredKeychainSignature {
         op_id: signature.op_id.to_string(),
         signer: signature.signer.to_string(),
+        signer_public_key: signature.signer_public_key.clone(),
         namespace: signature.namespace.clone(),
         signature: signature.signature.clone(),
         created_at_ms: signature.created_at.0,
@@ -4076,6 +4086,96 @@ fn sign_keychain_op_with_ssh(
     Ok(signature)
 }
 
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
+struct KeychainSignatureStatus {
+    total: usize,
+    verified: usize,
+    failed: usize,
+}
+
+fn verify_keychain_signatures(
+    store: &Store,
+    node: &LocalNode,
+) -> Result<KeychainSignatureStatus, NodeError> {
+    let ops = load_keychain_ops(store)?;
+    let ops_by_id = ops
+        .into_iter()
+        .map(|op| (op.id.to_string(), op))
+        .collect::<BTreeMap<_, _>>();
+    let signatures = store.list_keychain_signatures()?;
+    let total = signatures.len();
+    let mut verified = 0;
+    let mut failed = 0;
+    for signature in signatures {
+        let Some(op) = ops_by_id.get(&signature.op_id) else {
+            failed += 1;
+            continue;
+        };
+        if verify_keychain_signature_with_ssh(node, op, &signature)? {
+            verified += 1;
+        } else {
+            failed += 1;
+        }
+    }
+    Ok(KeychainSignatureStatus {
+        total,
+        verified,
+        failed,
+    })
+}
+
+fn verify_keychain_signature_with_ssh(
+    node: &LocalNode,
+    op: &KeychainOp,
+    signature: &StoredKeychainSignature,
+) -> Result<bool, NodeError> {
+    if signature.signer_public_key.trim().is_empty() {
+        return Ok(false);
+    }
+    if geth_ssh_identity::ensure_ssh_keygen_available().is_err() {
+        return Ok(false);
+    }
+
+    let verify_dir = node.paths.home().join("keychain-signatures").join("verify");
+    std::fs::create_dir_all(&verify_dir)?;
+    let stable_id = geth_crypto::blake3_hex(
+        format!(
+            "{}\0{}\0{}\0{}",
+            op.id, signature.signer, signature.namespace, signature.created_at_ms
+        )
+        .as_bytes(),
+    );
+    let payload_path = verify_dir.join(format!("{stable_id}.payload"));
+    let signature_path = verify_dir.join(format!("{stable_id}.sig"));
+    let allowed_signers_path = verify_dir.join(format!("{stable_id}.allowed-signers"));
+    std::fs::write(&payload_path, geth_keychain::keychain_signing_payload(op)?)?;
+    std::fs::write(&signature_path, &signature.signature)?;
+    std::fs::write(
+        &allowed_signers_path,
+        format!(
+            "{} {}\n",
+            signature.signer,
+            signature.signer_public_key.trim()
+        ),
+    )?;
+
+    let payload = std::fs::File::open(&payload_path)?;
+    let output = std::process::Command::new("ssh-keygen")
+        .arg("-Y")
+        .arg("verify")
+        .arg("-f")
+        .arg(&allowed_signers_path)
+        .arg("-I")
+        .arg(&signature.signer)
+        .arg("-n")
+        .arg(&signature.namespace)
+        .arg("-s")
+        .arg(&signature_path)
+        .stdin(std::process::Stdio::from(payload))
+        .output()?;
+    Ok(output.status.success())
+}
+
 fn load_keychain_ops(store: &Store) -> Result<Vec<KeychainOp>, NodeError> {
     store
         .list_keychain_ops()?

crates/geth-store/src/lib.rs

@@ -73,6 +73,7 @@ impl Store {
             CREATE TABLE IF NOT EXISTS keychain_signatures (
                 op_id TEXT NOT NULL,
                 signer TEXT NOT NULL,
+                signer_public_key TEXT NOT NULL DEFAULT '',
                 namespace TEXT NOT NULL,
                 signature BLOB NOT NULL,
                 created_at_ms INTEGER NOT NULL,
@@ -205,6 +206,30 @@ impl Store {
             INSERT OR IGNORE INTO meta(key, value) VALUES ('schema_version', '1');
             "#,
         )?;
+        self.add_column_if_missing(
+            "keychain_signatures",
+            "signer_public_key",
+            "TEXT NOT NULL DEFAULT ''",
+        )?;
+        Ok(())
+    }
+
+    fn add_column_if_missing(
+        &self,
+        table: &str,
+        column: &str,
+        definition: &str,
+    ) -> Result<(), StoreError> {
+        let mut stmt = self.conn.prepare(&format!("PRAGMA table_info({table})"))?;
+        let columns = stmt
+            .query_map([], |row| row.get::<_, String>(1))?
+            .collect::<Result<Vec<_>, _>>()?;
+        if !columns.iter().any(|name| name == column) {
+            self.conn.execute(
+                &format!("ALTER TABLE {table} ADD COLUMN {column} {definition}"),
+                [],
+            )?;
+        }
         Ok(())
     }
 
@@ -935,12 +960,13 @@ impl Store {
     ) -> Result<(), StoreError> {
         self.conn.execute(
             r#"INSERT OR REPLACE INTO keychain_signatures(
-                   op_id, signer, namespace, signature, created_at_ms
+               op_id, signer, signer_public_key, namespace, signature, created_at_ms
                )
-               VALUES (?1, ?2, ?3, ?4, ?5)"#,
+               VALUES (?1, ?2, ?3, ?4, ?5, ?6)"#,
             params![
                 signature.op_id,
                 signature.signer,
+                signature.signer_public_key,
                 signature.namespace,
                 signature.signature,
                 signature.created_at_ms
@@ -951,16 +977,17 @@ impl Store {
 
     pub fn list_keychain_signatures(&self) -> Result<Vec<StoredKeychainSignature>, StoreError> {
         let mut stmt = self.conn.prepare(
-            r#"SELECT op_id, signer, namespace, signature, created_at_ms
+            r#"SELECT op_id, signer, signer_public_key, namespace, signature, created_at_ms
                FROM keychain_signatures ORDER BY created_at_ms, op_id, signer, namespace"#,
         )?;
         let rows = stmt.query_map([], |row| {
             Ok(StoredKeychainSignature {
                 op_id: row.get(0)?,
                 signer: row.get(1)?,
-                namespace: row.get(2)?,
-                signature: row.get(3)?,
-                created_at_ms: row.get(4)?,
+                signer_public_key: row.get(2)?,
+                namespace: row.get(3)?,
+                signature: row.get(4)?,
+                created_at_ms: row.get(5)?,
             })
         })?;
         rows.collect::<Result<Vec<_>, _>>()
@@ -1342,6 +1369,7 @@ pub struct StoredKeychainOp {
 pub struct StoredKeychainSignature {
     pub op_id: String,
     pub signer: String,
+    pub signer_public_key: String,
     pub namespace: String,
     pub signature: Vec<u8>,
     pub created_at_ms: i64,
@@ -1547,6 +1575,7 @@ mod tests {
         let signature = StoredKeychainSignature {
             op_id: "op:keychain:1".to_owned(),
             signer: "ssh:blake3:admin".to_owned(),
+            signer_public_key: "ssh-ed25519 AAAAADMIN eric@geth".to_owned(),
             namespace: "geth.keychain.v1@geth.local".to_owned(),
             signature: b"-----BEGIN SSH SIGNATURE-----".to_vec(),
             created_at_ms: 3,

crates/geth/tests/bootstrap.rs

@@ -710,6 +710,8 @@ fn keychain_init_and_status_use_local_keychain_log() {
             assert!(status.initialized);
             assert_eq!(status.admin_keys, 1);
             assert_eq!(status.signatures, 0);
+            assert_eq!(status.verified_signatures, 0);
+            assert_eq!(status.failed_signatures, 0);
             assert_eq!(status.users, 0);
         }
         other => panic!("unexpected response: {other:?}"),
@@ -752,6 +754,7 @@ fn keychain_init_can_record_openssh_signatures() {
             assert_eq!(signatures.len(), 2);
             assert!(signatures.iter().all(|signature| {
                 signature.namespace == "geth.keychain.v1@geth.local"
+                    && signature.signer_public_key.starts_with("ssh-ed25519 ")
                     && !signature.signature.is_empty()
             }));
         }
@@ -769,6 +772,8 @@ fn keychain_init_can_record_openssh_signatures() {
     match response {
         geth_control::ControlResponse::KeychainStatus(status) => {
             assert_eq!(status.signatures, 2);
+            assert_eq!(status.verified_signatures, 2);
+            assert_eq!(status.failed_signatures, 0);
         }
         other => panic!("unexpected response: {other:?}"),
     }

docs/architecture.md

@@ -239,8 +239,9 @@ reports the reduced local view. `keychain init --signing-key <path>` writes the
 canonical keychain signing payloads, runs `ssh-keygen -Y sign` with the explicit
 `geth.keychain.v1@geth.local` namespace, and stores the resulting OpenSSH
 signatures in local SQLite. `keychain status` reports the stored signature
-count. Verification and rejection of unsigned replicated keychain operations are
-still future work.
+count and verifies stored signatures against their canonical payloads with
+OpenSSH when possible. Rejection of unsigned or invalid replicated keychain
+operations is still future work.
 
 The authorization plane is `geth-auth`: resource-local signed operation logs,
 grants, revocations, groups, and `auth explain`. Auth operations reduce into a

docs/roadmap.md

@@ -175,10 +175,13 @@ resource-scoped capability decisions.
     `geth.keychain.v1@geth.local` namespace.
   - `[x]` Keychain OpenSSH signatures are stored in local SQLite.
   - `[x]` `geth keychain status` reports the stored keychain signature count.
+  - `[x]` `geth keychain status` verifies stored keychain signatures against
+    canonical payloads with OpenSSH when public key material is available.
   - `[x]` Missing `ssh-keygen` or unavailable hardware keys produce clear
     errors during signing.
   - `[x]` Tests cover signed keychain init with a generated local OpenSSH key
     when `ssh-keygen` is available.
+  - `[x]` Tests cover local OpenSSH verification of stored keychain signatures.
   - `[ ]` Future completion verifies signatures before accepting replicated
     keychain ops.