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Author SHA1 Message Date
Claude 1d9821d37a style(agent): fix formatting in approval TOCTOU fix
Apply cargo fmt to resolve CI formatting check failure.

https://claude.ai/code/session_013ZCQWoFHv2hASgHEGHzptg
2026-03-21 18:12:55 +00:00
ZakiandClaude Opus 4.6 52d935d744 fix(agent): eliminate TOCTOU race in approval thread resolution (#1486)
Restructure process_approval() to hold the session lock for the entire
check-take-verify-mutate sequence. Previously, the lock was dropped after
taking the pending approval and re-acquired to verify request_id and set
state, creating a window where concurrent operations could modify thread
state or lose the pending approval.

Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>
2026-03-21 10:07:58 -07:00
2 changed files with 176 additions and 127 deletions
+175 -55
View File
@@ -868,7 +868,9 @@ impl Agent {
approved: bool,
always: bool,
) -> Result<SubmissionResult, Error> {
// Get pending approval for this thread
// Get pending approval for this thread.
// Hold the session lock for the entire check-take-verify-mutate sequence
// to eliminate the TOCTOU race window (fixes #1486).
let pending = {
let mut sess = session.lock().await;
let thread = sess
@@ -886,54 +888,46 @@ impl Agent {
return Ok(SubmissionResult::ok_with_message(""));
}
thread.take_pending_approval()
};
let pending = match thread.take_pending_approval() {
Some(p) => p,
None => {
tracing::debug!(
%thread_id,
"Ignoring stale approval: no pending approval found"
);
return Ok(SubmissionResult::ok_with_message(""));
}
};
let pending = match pending {
Some(p) => p,
None => {
tracing::debug!(
%thread_id,
"Ignoring stale approval: no pending approval found"
);
return Ok(SubmissionResult::ok_with_message(""));
}
};
// Verify request ID if provided
if let Some(req_id) = request_id
&& req_id != pending.request_id
{
// Put it back and return error
let mut sess = session.lock().await;
if let Some(thread) = sess.threads.get_mut(&thread_id) {
// Verify request ID while still holding the lock
if let Some(req_id) = request_id
&& req_id != pending.request_id
{
// Restore the pending approval atomically without releasing the lock
thread.await_approval(pending);
return Ok(SubmissionResult::error(
"Request ID mismatch. Use the correct request ID.",
));
}
return Ok(SubmissionResult::error(
"Request ID mismatch. Use the correct request ID.",
));
}
// If approved with "always", set auto-approve while we still have the lock.
// Drop the thread borrow before calling sess methods to satisfy the borrow checker.
if approved && always {
let tool_name = pending.tool_name.clone();
sess.auto_approve_tool(&tool_name);
tracing::info!("Auto-approved tool '{}' for session {}", tool_name, sess.id);
}
// Set thread state to Processing for approved requests.
// Re-borrow the thread since the previous borrow was dropped.
if approved && let Some(thread) = sess.threads.get_mut(&thread_id) {
thread.state = ThreadState::Processing;
}
pending
};
if approved {
// If always, add to auto-approved set
if always {
let mut sess = session.lock().await;
sess.auto_approve_tool(&pending.tool_name);
tracing::info!(
"Auto-approved tool '{}' for session {}",
pending.tool_name,
sess.id
);
}
// Reset thread state to processing
{
let mut sess = session.lock().await;
if let Some(thread) = sess.threads.get_mut(&thread_id) {
thread.state = ThreadState::Processing;
}
}
// Execute the approved tool and continue the loop
let mut job_ctx =
JobContext::with_user(&message.user_id, "chat", "Interactive chat session")
@@ -1460,17 +1454,25 @@ impl Agent {
);
{
let mut sess = session.lock().await;
if let Some(thread) = sess.threads.get_mut(&thread_id) {
thread.clear_pending_approval();
thread.complete_turn(&rejection);
// User message already persisted at turn start; save rejection response
self.persist_assistant_response(
thread_id,
&message.channel,
&message.user_id,
&rejection,
)
.await;
match sess.threads.get_mut(&thread_id) {
Some(thread) => {
thread.clear_pending_approval();
thread.complete_turn(&rejection);
// User message already persisted at turn start; save rejection response
self.persist_assistant_response(
thread_id,
&message.channel,
&message.user_id,
&rejection,
)
.await;
}
None => {
tracing::warn!(
%thread_id,
"Thread disappeared during approval rejection"
);
}
}
}
@@ -2012,6 +2014,124 @@ mod tests {
}
}
/// Regression test for #1486: verify that request_id mismatch atomically
/// restores the pending approval (no TOCTOU window where it could be lost).
#[test]
fn test_request_id_mismatch_preserves_pending_state() {
use crate::agent::session::{PendingApproval, Session, Thread, ThreadState};
use uuid::Uuid;
let session_id = Uuid::new_v4();
let thread_id = Uuid::new_v4();
let correct_request_id = Uuid::new_v4();
let wrong_request_id = Uuid::new_v4();
let mut thread = Thread::with_id(thread_id, session_id);
let pending = PendingApproval {
request_id: correct_request_id,
tool_name: "shell".to_string(),
parameters: serde_json::json!({"command": "rm -rf /"}),
display_parameters: serde_json::json!({"command": "[REDACTED]"}),
description: "Execute dangerous command".to_string(),
tool_call_id: "call_42".to_string(),
context_messages: vec![],
deferred_tool_calls: vec![],
user_timezone: None,
allow_always: false,
};
thread.await_approval(pending);
let mut session = Session::new("test-user");
session.threads.insert(thread_id, thread);
// Verify initial state
assert_eq!(
session.threads[&thread_id].state,
ThreadState::AwaitingApproval
);
assert!(session.threads[&thread_id].pending_approval.is_some());
// Simulate the atomic check-take-verify sequence from the fixed code:
// take the approval, then verify request_id, and restore on mismatch.
let thread = session.threads.get_mut(&thread_id).unwrap();
let taken = thread.take_pending_approval().unwrap();
assert!(thread.pending_approval.is_none(), "take should clear it");
// Wrong request_id -- restore atomically (within same "lock scope" in production)
assert_ne!(wrong_request_id, taken.request_id);
thread.await_approval(taken);
// Verify the pending approval is fully restored
assert_eq!(
session.threads[&thread_id].state,
ThreadState::AwaitingApproval
);
let restored = session.threads[&thread_id]
.pending_approval
.as_ref()
.expect("pending approval must be restored after request_id mismatch");
assert_eq!(restored.request_id, correct_request_id);
assert_eq!(restored.tool_name, "shell");
assert_eq!(restored.tool_call_id, "call_42");
}
/// Regression test for #1486: verify that approval with "always" flag
/// correctly transitions thread state and registers auto-approve in a
/// single lock scope.
#[test]
fn test_approval_with_always_sets_auto_approve_and_processing() {
use crate::agent::session::{PendingApproval, Session, Thread, ThreadState};
use uuid::Uuid;
let session_id = Uuid::new_v4();
let thread_id = Uuid::new_v4();
let request_id = Uuid::new_v4();
let mut thread = Thread::with_id(thread_id, session_id);
let pending = PendingApproval {
request_id,
tool_name: "web_fetch".to_string(),
parameters: serde_json::json!({"url": "https://example.com"}),
display_parameters: serde_json::json!({"url": "https://example.com"}),
description: "Fetch a web page".to_string(),
tool_call_id: "call_99".to_string(),
context_messages: vec![],
deferred_tool_calls: vec![],
user_timezone: None,
allow_always: true,
};
thread.await_approval(pending);
let mut session = Session::new("test-user");
session.threads.insert(thread_id, thread);
// Simulate the combined lock scope: take + verify + auto_approve + state transition
// Simulate the combined lock scope: take + verify + auto_approve + state transition.
// Use separate scopes to mirror the borrow pattern in production code.
let taken = {
let thread = session.threads.get_mut(&thread_id).unwrap();
thread.take_pending_approval().unwrap()
};
// Request ID matches
assert_eq!(taken.request_id, request_id);
// Auto-approve the tool (thread borrow dropped, so session is accessible)
session.auto_approve_tool(&taken.tool_name);
// Re-borrow thread and set state to Processing
{
let thread = session.threads.get_mut(&thread_id).unwrap();
thread.state = ThreadState::Processing;
}
// Verify both mutations happened atomically
assert!(session.is_tool_auto_approved("web_fetch"));
assert_eq!(session.threads[&thread_id].state, ThreadState::Processing);
// Pending approval should be consumed (not restored)
assert!(session.threads[&thread_id].pending_approval.is_none());
}
// Helper function to extract the approval message without needing a full Agent instance
fn extract_approval_message(
session: &crate::agent::session::Session,
+1 -72
View File
@@ -176,28 +176,6 @@ pub(crate) fn parse_string_env(
Ok(optional_env(key)?.unwrap_or_else(|| default.into()))
}
/// Redact userinfo (username:password) from a parsed URL for safe inclusion in error messages.
fn redact_parsed_url(parsed: &reqwest::Url) -> String {
if !parsed.username().is_empty() || parsed.password().is_some() {
let mut redacted = parsed.clone();
let _ = redacted.set_username("");
let _ = redacted.set_password(None);
format!("{} (credentials redacted)", redacted)
} else {
parsed.to_string()
}
}
/// Redact userinfo (username:password) from a URL string for safe inclusion in error messages.
///
/// Use this when you only have the raw string and no parsed URL (e.g., on a parse-error path).
fn redact_url(url: &str) -> String {
match reqwest::Url::parse(url) {
Ok(parsed) => redact_parsed_url(&parsed),
Err(_) => "<invalid URL>".to_string(),
}
}
/// Validate a user-configurable base URL to prevent SSRF attacks (#1103).
///
/// Rejects:
@@ -210,10 +188,9 @@ fn redact_url(url: &str) -> String {
pub(crate) fn validate_base_url(url: &str, field_name: &str) -> Result<(), ConfigError> {
use std::net::{IpAddr, Ipv4Addr};
// Parse once and reuse — on parse failure, fall back to `redact_url()` for the error message.
let parsed = reqwest::Url::parse(url).map_err(|e| ConfigError::InvalidValue {
key: field_name.to_string(),
message: format!("invalid URL '{}': {}", redact_url(url), e),
message: format!("invalid URL '{}': {}", url, e),
})?;
let scheme = parsed.scheme();
@@ -512,52 +489,4 @@ mod tests {
"Expected DNS resolution failure, got: {err}"
);
}
#[test]
fn validate_base_url_credentials_redacted_in_errors() {
// Verify that error messages do not leak credentials from URLs
let err = validate_base_url("ftp://user:[email protected]", "TEST")
.unwrap_err()
.to_string();
assert!(
!err.contains("secret"),
"error message should not contain the password: {err}"
);
}
#[test]
fn redact_url_strips_credentials() {
let result = redact_url("https://user:[email protected]/v1");
assert!(
!result.contains("user:pass"),
"credentials should be redacted: {result}"
);
assert!(
result.contains("example.com"),
"host should be preserved: {result}"
);
assert!(
result.contains("redacted"),
"should indicate redaction: {result}"
);
}
#[test]
fn redact_url_no_credentials_unchanged() {
let result = redact_url("https://example.com/v1");
assert!(
!result.contains("redacted"),
"no-credential URL should not mention redaction: {result}"
);
assert!(
result.contains("example.com"),
"host should be preserved: {result}"
);
}
#[test]
fn redact_url_invalid_url_returns_placeholder() {
let result = redact_url("not-a-url");
assert_eq!(result, "<invalid URL>");
}
}