fix(auth): refresh OAuth2 tokens in long-running watch/subscribe loops#407
fix(auth): refresh OAuth2 tokens in long-running watch/subscribe loops#407meme8383 wants to merge 5 commits intogoogleworkspace:mainfrom
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area: auth
area: core
Summary of ChangesHello, I'm Gemini Code Assist1! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed! This pull request significantly enhances the reliability of long-running operations, specifically Gmail watch and Workspace Events subscribe, by implementing a robust mechanism for refreshing OAuth2 access tokens. It introduces a new Highlights
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Code Review
This pull request introduces a robust mechanism for refreshing OAuth2 tokens in long-running processes using an AccessTokenProvider trait, improving reliability and correctly refactoring watch and subscribe helpers. However, a critical security concern has been identified: potential URL injection vulnerabilities in both the Gmail watch and Workspace Events subscribe helpers, where user-supplied subscription names and event types are used to construct API URLs without sufficient validation. Additionally, the current implementation fetches tokens excessively within loops, leading to unnecessary performance overhead. It is recommended to address the URL injection by applying strict resource name validation consistently across all helpers, and to optimize token usage by reusing tokens within a single loop iteration where they are still valid.
| .bearer_auth(pubsub_token) | ||
| let pull_future = runtime | ||
| .client | ||
| .post(format!("{}/{subscription}:pull", runtime.pubsub_api_base)) |
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The subscription parameter, which can be supplied by the user via the --subscription flag, is used to construct API URLs without any validation or sanitization. An attacker providing a malicious subscription name containing path traversal segments (e.g., ../../) or query parameters could cause the application to make requests to unintended API endpoints on the pubsub.googleapis.com host. This is inconsistent with other parts of the application (like src/helpers/events/subscribe.rs) where resource names are strictly validated using crate::validate::validate_resource_name.
| // Delete Pub/Sub topic | ||
| if let Some(ref topic) = topic_name { | ||
| let _ = client | ||
| .delete(format!("{PUBSUB_API_BASE}/{topic}")) |
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The topic name is constructed using a slug derived from user-supplied event-types without validation. If an attacker provides an event type containing path traversal segments (e.g., google.workspace.drive.file.v1.updated/../something), the resulting topic name will contain these segments, leading to a URL path traversal vulnerability when calling the Pub/Sub API. Although project is validated, the slug part of the resource name remains a vector for injection.
Remove redundant access_token() calls for acknowledge requests (both loops) and per-message Gmail fetches. The token obtained at the start of the iteration / function is still valid and is now reused for all HTTP calls within the same pass. Addresses review feedback from gemini-code-assist.
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/gemini review |
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Code Review
This pull request introduces an AccessTokenProvider trait and ScopedTokenProvider to enable long-running helpers, specifically for Gmail watch and Workspace Events subscribe, to refresh OAuth access tokens before each API call, preventing token expiration issues. The changes involve refactoring token acquisition in src/auth.rs, src/helpers/events/subscribe.rs, and src/helpers/gmail/watch.rs to use these new providers, along with adding new test utilities and tests. Review comments highlight several issues: potential URL path traversal vulnerabilities in both the Pub/Sub subscription and Gmail watch cleanup operations due to unvalidated user input, code duplication of the FakeTokenProvider test utility, and a re-introduced bug in the Gmail watch helper where the gmail_token might still expire during long fetch_and_output_messages operations.
| .bearer_auth(pubsub_token) | ||
| let pull_future = runtime | ||
| .client | ||
| .post(format!("{}/{subscription}:pull", runtime.pubsub_api_base)) |
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The subscription variable, which can be directly controlled by the user via the --subscription flag, is used to construct a URL path without validation. This allows for a URL path traversal vulnerability. An attacker could provide a value like ../../evil to manipulate the request URL and potentially hit unauthorized endpoints on the Pub/Sub API (e.g., https://pubsub.googleapis.com/v1/../../evil:pull resolves to https://pubsub.googleapis.com/evil:pull).
To remediate this, validate the subscription argument using crate::validate::validate_resource_name in parse_watch_args or before it is used in handle_watch.
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As above: This is pre-existing on main. Opened #408 to track.
| "https://pubsub.googleapis.com/v1/{subscription}:pull" | ||
| )) | ||
| .bearer_auth(token) | ||
| .post(format!("{pubsub_api_base}/{subscription}:pull")) |
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The subscription parameter in pull_loop can be a resource name constructed using a 'slug' derived from user-provided event-types. Since the event types are not validated, they can contain path traversal sequences (e.g., ..) that propagate into the slug and subsequently into the subscription resource name. This allows an attacker to manipulate the Pub/Sub API request URL. For example, a malicious event type could result in a URL like https://pubsub.googleapis.com/v1/projects/{project}/topics/gws-../../evil:pull.
To remediate this, validate each event type in parse_subscribe_args or validate the resulting slug using crate::validate::validate_resource_name before using it to construct resource names.
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As above: This is pre-existing on main. Opened #408 to track.
| let gmail_token = gmail_token_provider | ||
| .access_token() | ||
| .await | ||
| .context("Failed to get Gmail token")?; |
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The gmail_token is fetched only once at the beginning of fetch_and_output_messages. The subsequent loop over msg_ids (starting on line 422) fetches each message using this same token. If there are many messages to fetch, this loop could take longer than the token's lifetime (~1 hour), causing the operation to fail mid-way. This re-introduces the same class of bug this PR aims to fix.
To ensure tokens do not expire during a long-running fetch operation, consider moving this token acquisition logic inside the for msg_id in msg_ids loop, so that a fresh token is used for each message fetch.
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This contradicts the earlier review about N+1 Token requests. It seems unlikely that iterating over the messages will take longer than an hour, so I will revert this fix. Another solution may be to re-fetch the token on 401 errors in the loop.
…r message - Move FakeTokenProvider to auth.rs behind #[cfg(test)] so both helper test modules share one definition. - Refresh the Gmail token per message inside fetch_and_output_messages to guard against expiry during large batches. - Update test expectations accordingly.
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/gemini review |
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Code Review
This pull request introduces a robust mechanism for refreshing OAuth2 tokens in long-running processes by using an AccessTokenProvider trait. The refactoring of the gmail +watch and events +subscribe helpers to use this provider is well-executed and addresses the critical issue of token expiration. The addition of constants for API base URLs and comprehensive tests, including mock servers, significantly improves the code's testability and reliability.
I've identified a couple of high-severity issues in the cleanup logic where a failure to refresh a token is not handled correctly, potentially misleading the user. Please see the detailed comments.
Move the success message inside the token-refresh guard and add an else branch that warns about potential orphaned resources.
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/gemini review |
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Code Review
This pull request introduces an AccessTokenProvider trait and its implementation, ScopedTokenProvider, to enable refreshing OAuth access tokens for long-running operations. The Gmail watch and Workspace Events subscribe helpers are refactored to use these new token providers, ensuring that fresh access tokens are obtained before each Pub/Sub and Gmail API request, including during cleanup and for individual message fetches in Gmail. This prevents token expiration issues in long-running processes. New test helpers and integration tests were added to validate this token refreshing behavior.
Note: Security Review did not run due to the size of the PR.
A single history batch won't approach the token's 1-hour lifetime, so per-message refresh is unnecessary overhead. The outer watch_pull_loop already refreshes tokens each iteration for long-running resilience.
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/gemini review |
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Code Review
The pull request introduces an AccessTokenProvider trait and ScopedTokenProvider to enable long-running helpers (Gmail watch and Workspace Events subscribe) to refresh OAuth access tokens before each API request, addressing potential token expiration. The subscribe.rs and watch.rs helpers are updated to utilize this new token refresh mechanism for Pub/Sub and Gmail API calls, including cleanup operations. New tests were added to verify this behavior. However, the review comments highlight that the newly added tests for token refreshing in both subscribe.rs and watch.rs are insufficient. They currently use single tokens for multiple requests, failing to properly validate that tokens are indeed refreshed between calls. Additionally, a potential issue was identified in watch.rs where the Gmail token for fetching individual messages is only refreshed once per fetch_and_output_messages call, which could still lead to expiration if many messages are processed. This token should be refreshed before each individual message fetch for improved robustness.
| async fn test_pull_loop_refreshes_pubsub_token_between_requests() { | ||
| let client = reqwest::Client::new(); | ||
| let token_provider = FakeTokenProvider::new(["pubsub-token"]); | ||
| let (pubsub_base, requests, server) = spawn_subscribe_server().await; | ||
| let config = SubscribeConfigBuilder::default() | ||
| .subscription(Some(SubscriptionName( | ||
| "projects/test/subscriptions/demo".to_string(), | ||
| ))) | ||
| .max_messages(1_u32) | ||
| .poll_interval(1_u64) | ||
| .once(true) | ||
| .build() | ||
| .unwrap(); | ||
|
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||
| pull_loop( | ||
| &client, | ||
| &token_provider, | ||
| "projects/test/subscriptions/demo", | ||
| config, | ||
| &pubsub_base, | ||
| ) | ||
| .await | ||
| .unwrap(); | ||
|
|
||
| server.await.unwrap(); | ||
|
|
||
| let requests = requests.lock().await; | ||
| assert_eq!(requests.len(), 2); | ||
| assert_eq!(requests[0].0, "/v1/projects/test/subscriptions/demo:pull"); | ||
| assert_eq!(requests[0].1, "authorization: Bearer pubsub-token"); | ||
| assert_eq!( | ||
| requests[1].0, | ||
| "/v1/projects/test/subscriptions/demo:acknowledge" | ||
| ); | ||
| assert_eq!(requests[1].1, "authorization: Bearer pubsub-token"); | ||
| } |
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The test name test_pull_loop_refreshes_pubsub_token_between_requests suggests it verifies token refreshing, but it currently provides only a single token and asserts it's reused. This doesn't test the refresh logic. To properly test this, the FakeTokenProvider should be initialized with two distinct tokens, and the test should assert that the pull and acknowledge requests use different tokens, reflecting the implementation change to refresh the token for each request.
async fn test_pull_loop_refreshes_pubsub_token_between_requests() {
let client = reqwest::Client::new();
let token_provider = FakeTokenProvider::new(["token-for-pull", "token-for-ack"]);
let (pubsub_base, requests, server) = spawn_subscribe_server().await;
let config = SubscribeConfigBuilder::default()
.subscription(Some(SubscriptionName(
"projects/test/subscriptions/demo".to_string(),
)))
.max_messages(1_u32)
.poll_interval(1_u64)
.once(true)
.build()
.unwrap();
pull_loop(
&client,
&token_provider,
"projects/test/subscriptions/demo",
config,
&pubsub_base,
)
.await
.unwrap();
server.await.unwrap();
let requests = requests.lock().await;
assert_eq!(requests.len(), 2);
assert_eq!(requests[0].0, "/v1/projects/test/subscriptions/demo:pull");
assert_eq!(requests[0].1, "authorization: Bearer token-for-pull");
assert_eq!(
requests[1].0,
"/v1/projects/test/subscriptions/demo:acknowledge"
);
assert_eq!(requests[1].1, "authorization: Bearer token-for-ack");
}There was a problem hiding this comment.
This test confirms that the token is fetched per loop iteration. As per earlier review, it does not refresh the token within the same loop for the ack.
| for msg_id in msg_ids { | ||
| // Fetch full message | ||
| let msg_url = format!( | ||
| "https://gmail.googleapis.com/gmail/v1/users/me/messages/{}", | ||
| "{gmail_api_base}/users/me/messages/{}", | ||
| crate::validate::encode_path_segment(&msg_id), | ||
| ); | ||
| let msg_resp = client | ||
| .get(&msg_url) | ||
| .query(&[("format", msg_format)]) | ||
| .bearer_auth(gmail_token) | ||
| .bearer_auth(&gmail_token) | ||
| .send() | ||
| .await; |
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The Gmail token is fetched once at the start of fetch_and_output_messages and then reused for all message fetch requests inside the loop. If there are many messages, this loop can take a long time, and the token could expire. To make this more robust, the token should be refreshed inside the loop before each message is fetched.
for msg_id in msg_ids {
let gmail_token = gmail_token_provider
.access_token()
.await
.context("Failed to get Gmail token for message fetch")?;
let msg_url = format!(
"{gmail_api_base}/users/me/messages/{}",
crate::validate::encode_path_segment(&msg_id),
);
let msg_resp = client
.get(&msg_url)
.query(&[("format", msg_format)])
.bearer_auth(&gmail_token)
.send()
.await;There was a problem hiding this comment.
As above: this contradicts the earlier review about N+1 Token requests. It seems unlikely that iterating over the messages will take longer than an hour.
| async fn test_watch_pull_loop_refreshes_tokens_for_each_request() { | ||
| let client = reqwest::Client::new(); | ||
| let pubsub_provider = FakeTokenProvider::new(["pubsub-token"]); | ||
| let gmail_provider = FakeTokenProvider::new(["gmail-token"]); | ||
| let (pubsub_base, gmail_base, requests, server) = spawn_watch_server().await; | ||
| let mut last_history_id = 1; | ||
| let config = WatchConfig { | ||
| project: None, | ||
| subscription: None, | ||
| topic: None, | ||
| label_ids: None, | ||
| max_messages: 10, | ||
| poll_interval: 1, | ||
| format: "full".to_string(), | ||
| once: true, | ||
| cleanup: false, | ||
| output_dir: None, | ||
| }; | ||
| let sanitize_config = crate::helpers::modelarmor::SanitizeConfig { | ||
| template: None, | ||
| mode: crate::helpers::modelarmor::SanitizeMode::Warn, | ||
| }; | ||
|
|
||
| let runtime = WatchRuntime { | ||
| client: &client, | ||
| pubsub_token_provider: &pubsub_provider, | ||
| gmail_token_provider: &gmail_provider, | ||
| sanitize_config: &sanitize_config, | ||
| pubsub_api_base: &pubsub_base, | ||
| gmail_api_base: &gmail_base, | ||
| }; | ||
|
|
||
| watch_pull_loop( | ||
| &runtime, | ||
| "projects/test/subscriptions/demo", | ||
| &mut last_history_id, | ||
| config, | ||
| ) | ||
| .await | ||
| .unwrap(); | ||
|
|
||
| server.await.unwrap(); | ||
|
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| let requests = requests.lock().await; | ||
| assert_eq!(requests.len(), 4); | ||
| assert_eq!(requests[0].0, "/v1/projects/test/subscriptions/demo:pull"); | ||
| assert_eq!(requests[0].1, "authorization: Bearer pubsub-token"); | ||
| assert_eq!( | ||
| requests[1].0, | ||
| "/gmail/v1/users/me/history?startHistoryId=1&historyTypes=messageAdded" | ||
| ); | ||
| assert_eq!(requests[1].1, "authorization: Bearer gmail-token"); | ||
| assert_eq!( | ||
| requests[2].0, | ||
| "/gmail/v1/users/me/messages/msg%2D1?format=full" | ||
| ); | ||
| assert_eq!(requests[2].1, "authorization: Bearer gmail-token"); | ||
| assert_eq!( | ||
| requests[3].0, | ||
| "/v1/projects/test/subscriptions/demo:acknowledge" | ||
| ); | ||
| assert_eq!(requests[3].1, "authorization: Bearer pubsub-token"); | ||
| assert_eq!(last_history_id, 2); | ||
| } |
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This test's name implies it checks for token refreshes, but it provides only a single token for Pub/Sub and a single token for Gmail, and asserts they are reused across multiple requests. This doesn't actually test the refresh mechanism. With the suggested implementation changes to refresh tokens before each request, this test would fail. It should be updated to provide distinct tokens for each of the four API calls and assert that the correct token is used for each one, ensuring the refresh logic is properly verified.
async fn test_watch_pull_loop_refreshes_tokens_for_each_request() {
let client = reqwest::Client::new();
let pubsub_provider = FakeTokenProvider::new(["pubsub-token-1", "pubsub-token-2"]);
let gmail_provider = FakeTokenProvider::new(["gmail-token-1", "gmail-token-2"]);
let (pubsub_base, gmail_base, requests, server) = spawn_watch_server().await;
let mut last_history_id = 1;
let config = WatchConfig {
project: None,
subscription: None,
topic: None,
label_ids: None,
max_messages: 10,
poll_interval: 1,
format: "full".to_string(),
once: true,
cleanup: false,
output_dir: None,
};
let sanitize_config = crate::helpers::modelarmor::SanitizeConfig {
template: None,
mode: crate::helpers::modelarmor::SanitizeMode::Warn,
};
let runtime = WatchRuntime {
client: &client,
pubsub_token_provider: &pubsub_provider,
gmail_token_provider: &gmail_provider,
sanitize_config: &sanitize_config,
pubsub_api_base: &pubsub_base,
gmail_api_base: &gmail_base,
};
watch_pull_loop(
&runtime,
"projects/test/subscriptions/demo",
&mut last_history_id,
config,
)
.await
.unwrap();
server.await.unwrap();
let requests = requests.lock().await;
assert_eq!(requests.len(), 4);
assert_eq!(requests[0].0, "/v1/projects/test/subscriptions/demo:pull");
assert_eq!(requests[0].1, "authorization: Bearer pubsub-token-1");
assert_eq!(
requests[1].0,
"/gmail/v1/users/me/history?startHistoryId=1&historyTypes=messageAdded"
);
assert_eq!(requests[1].1, "authorization: Bearer gmail-token-1");
assert_eq!(
requests[2].0,
"/gmail/v1/users/me/messages/msg%2D1?format=full"
);
assert_eq!(requests[2].1, "authorization: Bearer gmail-token-2");
assert_eq!(
requests[3].0,
"/v1/projects/test/subscriptions/demo:acknowledge"
);
assert_eq!(requests[3].1, "authorization: Bearer pubsub-token-2");
assert_eq!(last_history_id, 2);
}There was a problem hiding this comment.
This test confirms that the token is fetched per loop iteration. As per earlier review, it does not refresh the token within the same loop for the ack.
meme8383
changed the title
2 participants
Summary
AccessTokenProvidertrait andScopedTokenProviderinauth.rsso long-running helpers can request fresh tokens before each API call instead of holding a single token string that expires after ~1 hourgmail +watch(watch_pull_loop) andevents +subscribe(pull_loop) to accept a&dyn AccessTokenProviderand refresh tokens per-requestPUBSUB_API_BASE/GMAIL_API_BASEURL constants to enable test injectionTest plan
cargo test— 553 tests pass (3 new)cargo clippy -- -D warnings— cleantest_scoped_token_provider_uses_get_token— verifiesScopedTokenProviderdelegates toget_tokentest_pull_loop_refreshes_pubsub_token_between_requests— fake TCP server +FakeTokenProviderverify each Pub/Sub request uses a distinct fresh tokentest_watch_pull_loop_refreshes_tokens_for_each_request— same pattern for Gmail watch, verifying all 4 HTTP calls (pull, history, message fetch, ack) each get a fresh tokenCloses #392
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