diff --git a/bin/tee-vault-admin/src/command.rs b/bin/tee-vault-admin/src/command.rs
index b39c05a..607bca3 100644
--- a/bin/tee-vault-admin/src/command.rs
+++ b/bin/tee-vault-admin/src/command.rs
@@ -58,7 +58,7 @@ pub async fn post_command(
     hasher.update(item.commands.as_bytes());
     let hash = hasher.finalize();
     let digest = hex::encode(hash);
-    admin_state.last_digest = digest.clone();
+    admin_state.last_digest.clone_from(&digest);
     conn.store_secret(admin_state, "state").await?;
 
     let mut responds = VaultCommandsResponse {
diff --git a/bin/tee-vault-admin/src/sign.rs b/bin/tee-vault-admin/src/sign.rs
index eece999..973df93 100644
--- a/bin/tee-vault-admin/src/sign.rs
+++ b/bin/tee-vault-admin/src/sign.rs
@@ -82,7 +82,7 @@ pub async fn post_sign(
     hasher.update(item.sign_request_data.as_bytes());
     let hash = hasher.finalize();
     let digest = hex::encode(hash);
-    admin_state.last_digest = digest.clone();
+    admin_state.last_digest.clone_from(&digest);
     conn.store_secret(admin_state, "state").await?;
 
     // Sign SGX enclave
diff --git a/bin/vault-admin/src/main.rs b/bin/vault-admin/src/main.rs
index e2f6381..91d17e0 100644
--- a/bin/vault-admin/src/main.rs
+++ b/bin/vault-admin/src/main.rs
@@ -291,6 +291,7 @@ async fn send_sig_request(args: SignTeeArgs) -> Result<()> {
     // open out_file early to fail fast if it is not writable
     let mut out_file = OpenOptions::new()
         .create(true)
+        .truncate(true)
         .write(true)
         .open(&args.out)?;
 
diff --git a/crates/teepot/src/json/http.rs b/crates/teepot/src/json/http.rs
index af5d28e..d450906 100644
--- a/crates/teepot/src/json/http.rs
+++ b/crates/teepot/src/json/http.rs
@@ -122,17 +122,17 @@ pub struct AuthDataField {
 /// Vault auth
 #[derive(Debug, Default, Serialize, Deserialize)]
 pub struct AuthField {
-    /// TODO
+    /// if the auth token is renewable
     pub renewable: bool,
-    /// TODO
+    /// the lease duration of the auth token
     pub lease_duration: isize,
-    /// TODO
+    /// the policies of the auth token
     pub policies: Vec<String>,
-    /// TODO
+    /// the accessor of the auth token
     pub accessor: String,
-    /// TODO
+    /// the client token
     pub client_token: String,
-    /// TODO
+    /// additional metadata
     pub metadata: AuthMetadataField,
 }
 
@@ -141,7 +141,7 @@ pub struct AuthField {
 pub struct AuthResponse {
     /// vault auth
     pub auth: AuthField,
-    ///
+    /// vault auth data
     pub data: AuthDataField,
 }
 
diff --git a/flake.lock b/flake.lock
index 9cc68bb..0fd8f3b 100644
--- a/flake.lock
+++ b/flake.lock
@@ -238,17 +238,16 @@
         ]
       },
       "locked": {
-        "lastModified": 1707876656,
-        "narHash": "sha256-urnZg6e2JjziBosarDB1MnjPeVqcu3PeSqIpqQKYrdg=",
+        "lastModified": 1717985971,
+        "narHash": "sha256-24h/qKp0aeI+Ew13WdRF521kY24PYa5HOvw0mlrABjk=",
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "3ad32bb27c700b59306224e285b66577e3532dfc",
+        "rev": "abfe5b3126b1b7e9e4daafc1c6478d17f0b584e7",
         "type": "github"
       },
       "original": {
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "3ad32bb27c700b59306224e285b66577e3532dfc",
         "type": "github"
       }
     },
diff --git a/flake.nix b/flake.nix
index f5939a4..a6a4653 100644
--- a/flake.nix
+++ b/flake.nix
@@ -19,7 +19,7 @@
     };
 
     rust-overlay = {
-      url = "github:oxalica/rust-overlay?rev=3ad32bb27c700b59306224e285b66577e3532dfc";
+      url = "github:oxalica/rust-overlay";
       inputs.nixpkgs.follows = "nixsgx-flake/nixpkgs";
     };
 
diff --git a/rust-toolchain.toml b/rust-toolchain.toml
index 33bc70a..bac2303 100644
--- a/rust-toolchain.toml
+++ b/rust-toolchain.toml
@@ -1,3 +1,3 @@
 [toolchain]
-channel = "1.75"
+channel = "1.78"
 components = ["rustfmt", "clippy", "rust-src"]