feat: enhance OAuth flow validation and improve security checks; add credential read blocking and git operation safeguards

src/app/runtime/actions/mod.rs

@@ -1029,7 +1029,7 @@ fn maybe_trigger_review(state: &mut AppStateRest) {
     }
     state.push_toast(Toast::new(
         ToastKind::Info,
-        format!("{} file(s) modified this turn. Review available.", edit_count),
+        format!("{} file(s) modified this session. Review available.", edit_count),
     ));
 }
 
@@ -1116,11 +1116,17 @@ fn run_oauth_flow(provider: &str) -> anyhow::Result<String> {
     let state_token = format!("{:x}", sha2::Sha256::digest(rand_bytes(16)));
 
     let mut manager = OAuthManager::new(config.clone());
-    let _auth_url = manager.build_auth_url(&redirect_uri, &state_token, challenge.as_str());
+    let auth_url = manager.build_auth_url(&redirect_uri, &state_token, challenge.as_str());
+    if auth_url.is_empty() {
+        tracing::warn!("[oauth] auth_url was empty for provider '{}'", provider);
+    } else if webbrowser::open(&auth_url).is_err() {
+        tracing::warn!(
+            "[oauth] could not open browser for '{}'; user must open URL manually:\n{}",
+            provider, auth_url
+        );
+    }
 
-    // let _ = webbrowser::open(&auth_url);
-
-    let code = server.wait_for_code(120_000)?;
+    let code = server.wait_for_code(120_000, &state_token)?;
 
     manager.exchange_code(&code, &redirect_uri, verifier.as_str())
         .map_err(|e| anyhow::anyhow!("{}", e))?;
@@ -1139,15 +1145,24 @@ fn run_oauth_flow(provider: &str) -> anyhow::Result<String> {
     Ok(format!("Successfully authenticated with {}.", provider))
 }
 
-/// Generate `n` pseudo-random bytes from the current sub-second timestamp.
+/// Generate `n` pseudo-random bytes from the system clock mixed with a monotonic
+/// counter, providing sufficient unpredictability for a per-flow OAuth state
+/// token without a `rand` dependency.
 ///
 /// Why: avoids pulling in a full RNG crate for the OAuth state token;
-/// sufficient for a nonce that only needs to be unpredictable over the
-/// lifetime of a single OAuth flow.
+/// the counter ensures sequential invocations produce different outputs even
+/// within the same clock tick, which is sufficient for a short-lived nonce.
 fn rand_bytes(n: usize) -> Vec<u8> {
+    use std::sync::atomic::{AtomicU64, Ordering};
     use std::time::{SystemTime, UNIX_EPOCH};
-    let seed = SystemTime::now().duration_since(UNIX_EPOCH).unwrap_or_default().subsec_nanos();
-    (0..n).map(|i| ((seed >> (i % 4 * 8)) ^ (i as u32 * 2654435761)) as u8).collect()
+    static COUNTER: AtomicU64 = AtomicU64::new(0);
+    let counter = COUNTER.fetch_add(1, Ordering::Relaxed);
+    let seed = SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_nanos() as u64;
+    let base = seed ^ counter;
+    (0..n).map(|i| ((base >> ((i as u64 % 8) * 8)) ^ (i as u64 * 2654435761)) as u8).collect()
 }