fix(uploads): close multipart storage-quota bypass via quota-exempt contexts by waleedlatif1 · Pull Request #5155 · simstudioai/sim

waleedlatif1 · 2026-06-20T20:57:01Z

Summary

The multipart upload endpoint (POST /api/files/multipart) accepted the quota-exempt public-asset contexts og-images, profile-pictures, and workspace-logos, which skip checkStorageQuota. Any authenticated writer — including a free-tier account — could open arbitrarily large upload sessions (100 GB+ confirmed) that never counted against their plan limit, causing unbounded untracked storage cost (CWE-770).
Fix: remove those three contexts from ALLOWED_UPLOAD_CONTEXTS (joining logs), so every context the multipart endpoint serves is quota-enforced. The bypass is now structurally impossible.

Why this is the right (and backwards-compatible) fix

These contexts have no legitimate multipart flow: their client hooks hard-cap uploads at 5 MB (image-only), and the direct-upload strategy only switches to multipart above 50 MB — so they always route through the single-part presigned endpoint (which already enforces admin/image-type policy).
og-images has neither a client nor a server multipart write path.
No change to workspace / mothership / knowledge-base / chat / copilot / execution behavior; workspace/mothership keep their existing MAX_WORKSPACE_FILE_SIZE cap.

Type of Change

Bug fix (security)

Testing

Updated route.test.ts: every quota-exempt context (og-images, profile-pictures, workspace-logos, logs) now returns 400 Invalid storage context before any session/quota call; quota-enforced contexts still pass the quota check and initiate.
bunx tsc --noEmit — 0 errors; vitest multipart suite — 11/11 pass; bun run check:api-validation — passes.

Checklist

Code follows project style guidelines
Self-reviewed my changes
Tests added/updated and passing
No new warnings introduced
I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

…ontexts The multipart endpoint accepted the quota-exempt public-asset contexts (og-images, profile-pictures, workspace-logos), which skip checkStorageQuota, letting any authenticated writer open arbitrarily large upload sessions that never count against their plan limit. These contexts have no large-file flow: their client hooks hard-cap uploads at 5MB (image-only) and the direct-upload strategy only uses multipart above 50MB, so they always route through the presigned endpoint. Remove them from ALLOWED_UPLOAD_CONTEXTS (joining logs) so every context the multipart endpoint serves is quota-enforced.

vercel · 2026-06-20T20:57:07Z

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cursor · 2026-06-20T20:57:11Z

PR Summary

High Risk
Security fix on billing/storage enforcement; scope is limited to multipart allowlisting and tests, with no change to legitimate small-asset presigned flows.

Overview
Closes a storage-quota bypass on POST /api/files/multipart where og-images, profile-pictures, and workspace-logos were allowed to initiate multipart uploads while skipping checkStorageQuota, enabling very large uploads that did not count against plan limits.

Those three contexts are removed from ALLOWED_UPLOAD_CONTEXTS, alongside the existing logs exclusion, so multipart initiate only accepts quota-enforced contexts (knowledge-base, chat, copilot, mothership, execution, workspace). Comments in the route and QUOTA_EXEMPT_STORAGE_CONTEXTS document that quota-exempt assets stay on presigned/single-part paths only.

Initiate quota logic now keys off the validated storageContext after the allowlist check. Tests assert quota-enforced success paths and use it.each to reject all four quota-exempt contexts with 400 Invalid storage context before quota or S3 initiate run.

^{Reviewed by Cursor Bugbot for commit e8ffb15. Configure here.}

greptile-apps · 2026-06-20T20:59:55Z

Greptile Summary

This PR closes a storage-quota bypass in the multipart upload endpoint by removing the three quota-exempt public-asset contexts (profile-pictures, workspace-logos, og-images) from ALLOWED_UPLOAD_CONTEXTS, joining the already-excluded logs context. A minor correctness cleanup also swaps a redundant context as StorageContext cast for the already-typed storageContext local in the quota guard.

Security fix: quota-exempt contexts are now structurally unreachable at the multipart endpoint — the ALLOWED_UPLOAD_CONTEXTS and QUOTA_EXEMPT_STORAGE_CONTEXTS sets are now fully disjoint, making the bypass impossible without a code change.
Tests updated: parameterized it.each covers all four excluded contexts, and the "passes quota" path is verified end-to-end with mockInitiateS3MultipartUpload now properly wired into the S3 client mock.
Docs updated: the JSDoc on QUOTA_EXEMPT_STORAGE_CONTEXTS in types.ts is corrected to describe the new invariant (all exempt contexts excluded from multipart, not just logs).

Confidence Score: 5/5

Safe to merge — the change is a minimal, well-scoped removal of three context strings that had no legitimate multipart flow; it cannot regress existing quota-enforced uploads.

The fix is structurally sound: ALLOWED_UPLOAD_CONTEXTS and QUOTA_EXEMPT_STORAGE_CONTEXTS are now fully disjoint, so every context the multipart endpoint accepts is quota-checked. The quota guard itself was also cleaned up to use the already-cast local. Tests cover all four excluded contexts with a parameterized suite and verify the happy path end-to-end. No pre-existing quota-enforced contexts were removed or altered.

No files require special attention.

Important Files Changed

Filename	Overview
apps/sim/app/api/files/multipart/route.ts	Removes the three quota-exempt contexts from ALLOWED_UPLOAD_CONTEXTS and fixes a minor cast redundancy in the quota guard; logic is correct and the sets are now fully disjoint.
apps/sim/lib/uploads/shared/types.ts	JSDoc on QUOTA_EXEMPT_STORAGE_CONTEXTS updated to reflect the new invariant; no behavioral changes to the type definitions or the set itself.
apps/sim/app/api/files/multipart/route.test.ts	Tests are updated to cover all four excluded quota-exempt contexts via it.each and the happy-path now asserts both quota check and S3 initiation; mockInitiateS3MultipartUpload is properly wired into the S3 client mock.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A["POST /api/files/multipart?action=initiate"] --> B{Authenticated?}
    B -- No --> C[401 Unauthorized]
    B -- Yes --> D{Cloud storage enabled?}
    D -- No --> E[400 Cloud storage only]
    D -- Yes --> F{context in ALLOWED_UPLOAD_CONTEXTS?}
    
    F -- "No\n'og-images','profile-pictures',\n'workspace-logos','logs'" --> G["400 Invalid storage context\n(quota bypass blocked)"]
    
    F -- "Yes\n'knowledge-base','chat','copilot',\n'mothership','execution','workspace'" --> H{User has workspace write/admin?}
    H -- No --> I[403 Forbidden]
    H -- Yes --> J{context in QUOTA_EXEMPT_STORAGE_CONTEXTS?}
    
    J -- "Yes (dead path after fix)" --> K[Skip quota check]
    J -- "No (always taken now)" --> L["checkStorageQuota(userId, fileSize)"]
    L -- Denied --> M[413 Storage limit exceeded]
    L -- Allowed --> N[Initiate S3/Blob multipart upload]
    K --> N
    N --> O[Return uploadId + key + uploadToken]

%%{init: {'theme': 'base', 'themeVariables': {"darkMode": true, "background": "#0d1117", "primaryColor": "#21262d", "primaryTextColor": "#e6edf3", "primaryBorderColor": "#8b949e", "lineColor": "#8b949e", "textColor": "#e6edf3", "edgeLabelBackground": "#161b22", "actorBkg": "#21262d", "actorBorder": "#8b949e", "actorTextColor": "#e6edf3", "actorLineColor": "#8b949e", "signalColor": "#8b949e", "signalTextColor": "#e6edf3", "noteBkgColor": "#373320", "noteBorderColor": "#d4a72c", "noteTextColor": "#f0e6c0", "labelBoxBkgColor": "#21262d", "labelBoxBorderColor": "#8b949e", "labelTextColor": "#e6edf3", "loopTextColor": "#e6edf3", "activationBkgColor": "#30363d", "activationBorderColor": "#8b949e"}}}%%
flowchart TD
    A["POST /api/files/multipart?action=initiate"] --> B{Authenticated?}
    B -- No --> C[401 Unauthorized]
    B -- Yes --> D{Cloud storage enabled?}
    D -- No --> E[400 Cloud storage only]
    D -- Yes --> F{context in ALLOWED_UPLOAD_CONTEXTS?}
    
    F -- "No\n'og-images','profile-pictures',\n'workspace-logos','logs'" --> G["400 Invalid storage context\n(quota bypass blocked)"]
    
    F -- "Yes\n'knowledge-base','chat','copilot',\n'mothership','execution','workspace'" --> H{User has workspace write/admin?}
    H -- No --> I[403 Forbidden]
    H -- Yes --> J{context in QUOTA_EXEMPT_STORAGE_CONTEXTS?}
    
    J -- "Yes (dead path after fix)" --> K[Skip quota check]
    J -- "No (always taken now)" --> L["checkStorageQuota(userId, fileSize)"]
    L -- Denied --> M[413 Storage limit exceeded]
    L -- Allowed --> N[Initiate S3/Blob multipart upload]
    K --> N
    N --> O[Return uploadId + key + uploadToken]

_{Reviews (2): Last reviewed commit: "fix(uploads): close multipart storage-qu..." | Re-trigger Greptile}

waleedlatif1 · 2026-06-20T21:05:15Z

@greptile

waleedlatif1 · 2026-06-20T21:05:16Z

@cursor review

cursor

✅ Bugbot reviewed your changes and found no new issues!

Comment @cursor review or bugbot run to trigger another review on this PR

^{Reviewed by Cursor Bugbot for commit e8ffb15. Configure here.}

cursor Bot reviewed Jun 20, 2026

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waleedlatif1 merged commit 2f7d607 into staging Jun 20, 2026
16 checks passed

waleedlatif1 deleted the worktree-fix+multipart-quota-bypass branch June 20, 2026 21:07

waleedlatif1 mentioned this pull request Jun 20, 2026

v0.7.11: parallel subagents, new tools, rich markdown editor, governance, file sharing #5145

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fix(uploads): close multipart storage-quota bypass via quota-exempt contexts#5155

fix(uploads): close multipart storage-quota bypass via quota-exempt contexts#5155
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waleedlatif1 commented Jun 20, 2026

Summary

Why this is the right (and backwards-compatible) fix

Type of Change

Testing

Checklist

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PR Summary

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Greptile Summary

Confidence Score: 5/5

Important Files Changed

Flowchart

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