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fix(guardrails): remove the whole-blob scan from the files surface - #1121
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`/v1/files` decoded an uploaded file with `String::from_utf8_lossy` and checked the result as one synthetic user message, while `create_file` forwarded the ORIGINAL bytes to the provider. That scan cannot do its job: it feeds JSON syntax to keyword matchers, answers a file holding thousands of independent requests with a single verdict, can rewrite nothing, and on a binary upload inspects a run of replacement characters. The download side had the same shape. Nothing narrower repairs it — screening a batch file means decomposing it per JSONL record and running the ordinary per-record request chain, which is #1120. Removed: the input blob scan on `POST /v1/files`, the output blob scan on its response and on every `/v1/files*` read, and the `unscannable_body` refusal built on the input scan (added by #1113, narrowed by #1114, gated by #1115) together with the purpose classification it keyed on. `forward_simple` skips the output chain for the files surface alone. `/v1/files` is now `Posture::Unscreened` in the guardrail coverage census, which says what the surface does rather than claiming enforcement it no longer has. Behaviour change: an upload that began answering `422` with the `unscannable_body` tag after #1113 is forwarded again, under every declared `purpose`. Capability narrowing: guardrails no longer apply to the files surface at all. An upload or a download that a keyword, PII or remote guardrail would previously have blocked on a policy match now reaches the provider and the caller respectively. The published documentation says input and output guardrails cover Files request and response payloads; that coverage is gone until #1120 lands. Unchanged: `/v1/batches` and `/v1/fine_tuning/jobs` still scan their serialised JSON request bodies and their responses — a serialised request body is not a caller-uploaded blob — and the `unscannable_body` gate stays on `/v1/messages`, `/v1/messages/count_tokens` and `/mcp` tool results, with `fail_open` governing every guardrail kind as before. Refs #1120, #1022
📝 WalkthroughWalkthroughFile uploads and downloads now bypass input and output guardrails while preserving raw bytes. Batch and fine-tuning job requests retain applicable screening. Guardrail posture classifications, unit tests, end-to-end tests, and related documentation were updated. ChangesFile guardrail scope
Estimated code review effort: 3 (Moderate) | ~20 minutes Merge Risk: 🔵 Low · up to Files now intentionally bypass guardrail scanning while batch and fine-tuning routes remain screened. The implementation coverage is substantially aligned with that scope, but the job-response documentation and E2E error handling should be corrected to avoid misleading operators and masking test failures. Sequence Diagram(s)sequenceDiagram
participant Client
participant AisixProxy
participant Guardrails
participant Upstream
Client->>AisixProxy: Send file upload or download request
AisixProxy->>Upstream: Forward file bytes without scanning
Upstream-->>AisixProxy: Return file response
AisixProxy-->>Client: Relay response unchanged
Client->>AisixProxy: Send batch JSON request
AisixProxy->>Guardrails: Screen request content
Guardrails-->>AisixProxy: Reject matching content
AisixProxy-->>Client: Return content-filter error
Suggested reviewers: 🚥 Pre-merge checks | ✅ 6✅ Passed checks (6 passed)
Full details: E2e Test Quality ReviewExplanation PASS. The added E2E suite uses a real spawned gateway, etcd configuration, and a recording upstream. It covers uploads for three purpose classes, matching upload responses, verbatim downloads, and the Full details: Security CheckExplanation No issue matches the seven stated security categories in the pull-request changes. (1) The new file forwarding relays the requested provider payload, but it adds no logging or serialization of API keys, tokens, authentication headers, credentials, or internal configuration. (2) No database model, migration, or persistence change stores secrets. (3) File, batch, and fine-tuning handlers retain the ✨ Finishing Touches📝 Generate docstrings
🧪 Generate unit tests (beta)
Comment |
…ail-scan # Conflicts: # crates/aisix-proxy/AGENTS.md
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🔵 Needs a closer look
It deliberately narrows guardrail enforcement coverage on the files surface (a security/behavior change) and should receive final human sign-off even though tests appear to cover the intended scope boundary.
Pull request overview
This PR removes the guardrail “whole-blob” scanning logic from the /v1/files surface (upload, upload response, and read paths) because scanning a lossy UTF-8 decode of an opaque file blob cannot provide correct or actionable guardrail enforcement (no per-record decisions, no rewrite channel, and meaningless results for binary uploads/downloads). The change also updates the guardrail coverage census to explicitly represent the files surface as unscreened (rather than implying enforcement), and replaces/adjusts integration and E2E coverage to lock in the intended scope boundaries (files unscreened; batches/fine-tuning still screened).
Changes:
- Removed request/response blob scanning for
/v1/filesand skippedforward_simple’s output scan when the surface isFILES. - Added a new guardrail coverage posture (
Posture::Unscreened) and classified/v1/filesaccordingly. - Replaced the prior files “unscannable upload” E2E with a new “files guardrail scope” E2E that asserts files are not screened while
/v1/batchesremains screened.
File summaries
| File | Description |
|---|---|
| tests/e2e/src/cases/files-unscannable-upload-e2e.test.ts | Removed obsolete E2E that asserted the former /v1/files unscannable-body refusal/scanning behavior. |
| tests/e2e/src/cases/files-guardrail-scope-e2e.test.ts | Added E2E asserting guardrails do not apply to files upload/response/download, while /v1/batches remains screened. |
| crates/aisix-proxy/src/jobs.rs | Removed /v1/files input/output blob scans; skipped forward_simple output scan only for FILES; updated integration tests to match new scope. |
| crates/aisix-proxy/src/guardrail_coverage.rs | Introduced Posture::Unscreened and marked /v1/files as unscreened with a rationale pointing to #1120. |
| crates/aisix-proxy/src/mcp.rs | Updated test doc comment to reference /v1/messages (the relevant mirrored gate) rather than /v1/files. |
| crates/aisix-proxy/src/count_tokens.rs | Updated test doc comment to remove /v1/files reference. |
| crates/aisix-proxy/AGENTS.md | Updated guidance to reflect removal of the files-surface unscannable sites and clarify remaining “lossy scan” sites. |
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Inline comments:
In `@crates/aisix-proxy/AGENTS.md`:
- Around line 154-156: Update the jobs::scan_output_blob behavior description to
state that original batch or fine-tuning response bytes are relayed only when
the guardrail allows the response; note that forward_simple propagates the
blocking error before relaying bytes.
In `@tests/e2e/src/cases/files-guardrail-scope-e2e.test.ts`:
- Line 76: Update the response error handler in the affected test setup so
recorder errors are captured and surfaced during cleanup or propagated to the
active request; remove the no-op handling in res.on("error") and ensure upstream
recorder write failures fail the suite.
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📒 Files selected for processing (7)
crates/aisix-proxy/AGENTS.mdcrates/aisix-proxy/src/count_tokens.rscrates/aisix-proxy/src/guardrail_coverage.rscrates/aisix-proxy/src/jobs.rscrates/aisix-proxy/src/mcp.rstests/e2e/src/cases/files-guardrail-scope-e2e.test.tstests/e2e/src/cases/files-unscannable-upload-e2e.test.ts
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- tests/e2e/src/cases/files-unscannable-upload-e2e.test.ts
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…wo job surfaces that still screen Three statements elsewhere in the crate described the files surface as screened and are now false: - the `NO-GUARDRAIL-CHAIN` exemption on the retroactive batch billing row argued in part that "the upload that created the batch was screened at its own time". It no longer is. The exemption stands on its other half — no request, so no chain — and the false clause is dropped. The guard that enforces the marker checks only that it is present, so nothing would have caught this; - `guardrail_blocked_telemetry`'s `SURFACES` exemption said the jobs surfaces' screened text is an uploaded file. `/v1/files` screens nothing now, and `/v1/batches` / `/v1/fine_tuning/jobs` screen a re-serialised request envelope, never the upload; - the census reasons for `/v1/batches` and `/v1/fine_tuning/jobs` claimed neither could be driven in-crate without a prior upload. This PR's own `a_batch_create_is_still_screened` drives one with a synthesised routed id, which disproves it. They are now the only jobs surfaces that screen anything, so they are promoted to `Posture::Enforced` with fixtures and join the four behavioural censuses — refusal, refusal reporting, bypass reporting, and the operation label — instead of sitting outside them on a premise that no longer holds. Each guardrail fixture now blocks on ONE literal, and every literal the "must forward" legs depend on is pinned by a leg that must refuse on it: `custom_id` by `a_batch_create_is_still_screened` (its body carries the term now), `forbidden-term` by `a_fine_tuning_job_read_is_still_screened`, and the e2e's `BLOCKED_TERM` by the `/v1/batches` leg. Without that, a pattern that quietly stopped matching would turn every forwarding assertion into a tautology.
… policy (#1123) `transcription_output_text` fell back to `String::from_utf8_lossy` for the plain-text response formats (`text` / `srt` / `vtt`) and then relayed the original bytes. It consulted neither `refuses_unevaluable_output` nor `record_unevaluable_output_bypass`, so a guardrail attached to the response side was handed a text the caller never receives, and nothing recorded the gap. BEHAVIOUR CHANGE: a transcription or translation response the gateway cannot decode is now refused when a guardrail in scope both reads the response side and fails closed on it. The caller gets 422 `content_filter` with code `guardrail_unavailable` and the message "response rejected: a guardrail could not evaluate it (unscannable_body)", where the bytes were previously relayed. A row that fails open on the response side relays them as before, and its usage event now carries `guardrail_bypassed_reason: unscannable_body`. Same predicate, tag and envelope as `/mcp`'s tool-result arm; the response-side mirror of the gate #1115 put on `/v1/messages` and `/v1/messages/count_tokens`. Unlike those, the lossy text is still scanned when the chain does not refuse: a transcript is prose the caller reads, so only the bytes `from_utf8_lossy` replaced go unread. That is why this site is gated rather than removed the way the files surface was in #1121. Also corrects rustdoc that had gone stale and had already propagated into the published documentation. `SemanticConfig::deny_threshold` claimed `/a2a` attaches no guardrail attribution to its usage event and that `rerank` emits no usage event when the upstream reports no parsable usage. `/a2a` sets all six guardrail fields, and `rerank` emits whenever a guardrail attributed the request, which a semantic score alone does; two `rerank.rs` comments were wrong for the same reason. The replacement enumerates the input-hook-only surfaces, `/v1/audio/speech` among them.
Problem
/v1/filesran the guardrail chain overString::from_utf8_lossy(&file_bytes)and treated the result as one synthetic user message, whilecreate_filebuilt the outbound multipart part from the original bytes.GET /v1/files/{id}/contenthad the same shape on the way back, relaying the provider's bytes throughrelay_raw_body.That scan cannot do the job it was published as doing:
{"custom_id":"r1","messages":[{"role":"user",...rather than any request a caller wrote;U+FFFDreplacement characters and reports that as a clean scan.Narrowing the failure arm does not repair any of that, which is what #1113 → #1114 → #1115 were doing. The end state this surface needs is recorded in #1120: decompose a batch file per JSONL record and run the ordinary per-record request chain. This PR removes the scan that cannot work; it does not build #1120.
A scan that cannot do its job is worse than none here, because the published coverage statement is what deployments act on.
What is removed
scan_input_blobonPOST /v1/files— the upload blob scan.scan_output_blobon the upload response, and on every/v1/files*read. Those reads shareforward_simplewith the batch and fine-tuning reads, so the scan is skipped forsurface == FILESrather than deleted.unscannable_bodyrefusal built on the input scan (added by fix(guardrails): refuse an unscannable /v1/files upload instead of forwarding it #1113, narrowed to text purposes by fix(guardrails): refuse an unscannable /v1/files upload only under a text purpose #1114, gated on a fail-closed request-side reader by fix(guardrails): refuse an unscannable body only when a guardrail reads that side #1115), and with itTEXT_PURPOSES,Undecodableandundecodable_posture./v1/filesmoves fromPosture::EnforcedNotDrivableInCrateto a newPosture::Unscreenedin the guardrail coverage census. The census exists to say what each mounted surface owes an operator's chain, so it has to be able to say "caller content reaches an upstream here and nothing screens it" instead of misfiling that as enforcement or as a route carrying no caller text.What is deliberately kept
/v1/batchesand/v1/fine_tuning/jobs. Both callers ofscan_input_blobthere passserde_json::to_vecoutput — the re-serialised JSON request body, which is a different thing from a caller's uploaded blob and is screened the way any other request body is. Their response scans stay too. A test drives each.unscannable_bodygate on the other three sites from fix(guardrails): refuse an unscannable body only when a guardrail reads that side #1115:/v1/messages,/v1/messages/count_tokensand/mcptool results. Untouched, and their refusal tests still pass (messages::tests::unparseable_body_with_an_input_guardrail_is_refused,count_tokens::tests::unparseable_body_with_an_input_guardrail_is_refused, and the fail-closed leg ofmcp::tests::unparseable_tool_result_with_an_input_only_chain_is_allowed).fail_opengoverning every guardrail kind, from fix(guardrails): refuse an unscannable body only when a guardrail reads that side #1115. Unaffected.Behaviour change
An upload that began answering
422with theunscannable_bodytag after #1113 is forwarded again, under every declaredpurpose.Capability narrowing
Guardrails no longer apply to the files surface at all. An upload or a download that a keyword, PII or remote guardrail would previously have blocked on a policy match now reaches the provider and the caller respectively. The published guardrail behaviour page states that input and output guardrails cover Files request and response payloads; that is no longer true, and the paired documentation change follows this PR.
Claims the removal invalidated
Three statements elsewhere in the crate described the files surface as screened, and none of them is checked by anything mechanical:
NO-GUARDRAIL-CHAINexemption on the retroactive batch billing row argued in part that "the upload that created the batch was screened at its own time". The exemption still stands on its other half — no request, so no chain — and the false clause is gone.usage_attr's guard only checks that the marker is present, never what it says.guardrail_blocked_telemetry'sSURFACESexemption said the jobs surfaces' screened text is an uploaded file./v1/filesscreens nothing now, and the other two screen a re-serialised request envelope./v1/batchesand/v1/fine_tuning/jobsclaimed neither could be driven in-crate without a prior upload.a_batch_create_is_still_screenedin this PR drives one with a synthesised routed id, which disproves it. They are now the only jobs surfaces that screen anything, so they are promoted toPosture::Enforcedwith fixtures and join the four behavioural censuses — refusal, refusal reporting, bypass reporting, and the operation label — rather than staying outside them on a premise that no longer holds.Tests
Rust, driving the real router against a mock provider:
an_upload_is_forwarded_under_every_purpose_class— a blob that is both undecodable and a policy hit is forwarded byte-for-byte underpurpose=batch,purpose=assistantsand no purpose, with a fail-closed input row attached. The usage event carries no enforced hit and no bypass reason.an_upload_response_is_relayed_past_a_blocking_output_rowanda_file_download_is_relayed_past_a_blocking_output_row— the two response-side removals.a_batch_create_is_still_screenedanda_fine_tuning_job_read_is_still_screened— the scope boundary, on both hooks. The second is what fails if the files exemption is implemented by deletingforward_simple's scan instead of naming the surface it belongs to.E2E (
tests/e2e/src/cases/files-guardrail-scope-e2e.test.ts, replacingfiles-unscannable-upload-e2e.test.ts): a realaisixbinary + etcd + a recording upstream, one fail-closedhook_point: bothrow whose pattern is present in every fixture. Six legs cover the three purpose classes, the upload response, the download, and the/v1/batchesscope boundary.Each guardrail fixture blocks on ONE literal, and every literal the "must forward" legs depend on is pinned by a leg that must refuse on it —
custom_idbya_batch_create_is_still_screened,forbidden-termbya_fine_tuning_job_read_is_still_screened, the e2e'sBLOCKED_TERMby its/v1/batchesleg. Otherwise a pattern that quietly stopped matching would turn every forwarding assertion into a tautology.Mutation-checked. At the Rust layer, each of the five tests above was confirmed to fail with its own removal reverted: restoring the upload input scan, restoring the upload response scan, scanning every
forward_simplesurface, scanning none of them, and dropping the batch input scan. At the e2e layer, restoring the upload input scan and the blanket output scan turns all six legs red.Refs #1120, #1022