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Austin Drummond
80f9335950
## Summary Garage's SigV4 canonical-request builder trims leading/trailing whitespace from signed header values but does not collapse sequential internal whitespace, which the SigV4 spec requires: > Convert sequential spaces to a single space. — https://docs.aws.amazon.com/IAM/latest/UserGuide/create-signed-request.html AWS SDKs apply this normalization before computing the signature, but transmit the raw value on the wire. The receiver must therefore apply the same normalization when reconstructing the canonical request, otherwise the recomputed hash differs and the request is rejected as `Invalid signature`. Same class of canonicalization-drift bug as #1155 / !1382, but on the canonical-headers axis rather than the canonical-URI axis. ## Reproduction Surfaces in practice with `gitlab-runner`'s S3 cache uploader. I was in the midst of migrating my runner cache from AWS S3 to garage, but I noticed some shared runner caches were no longer uploading. I was using `sha256sum | sha256sum` to compute my cache keys, which leaves a trailing ` -` on the value. Once GitLab appends `-protected` for protected branches the resulting `x-amz-meta-cachekey` header value contains internal sequential whitespace and triggers the mismatch: ``` x-amz-meta-cachekey:php- --protected ^^ two spaces, preserved by Garage ``` Without the fix the included regression test (`test_presigned_put_with_user_metadata`) fails with HTTP 403; with the fix it returns 200. `aws-cli` is unaffected because it signs `Content-Type` rather than user metadata, so the specific code path with whitespace-bearing signed header values isn't exercised. ## Fix In `canonical_request` (`src/api/common/signature/payload.rs`), replace the `.trim()` call on the joined header value with the full SigV4 normalization — `split_whitespace().collect::<Vec<_>>().join(" ")` — which both trims edges and collapses internal runs. ## Tests * New regression test `test_presigned_put_with_user_metadata` covering a presigned PUT whose `x-amz-meta-*` value contains internal sequential whitespace. * Full integration suite passes: `40 passed; 0 failed; 2 ignored`. * `garage_api_common` unit tests pass: `18 passed; 0 failed`. ## Notes * Backwards-compatible: any signature that validated before still validates, because clients are spec-required to collapse on their side; Garage was only rejecting requests where the client had collapsed correctly but Garage hadn't. * No config or migration changes. * Fix applies to both presigned-URL and Authorization-header code paths since they share the canonical-request builder. Reviewed-on: https://git.deuxfleurs.fr/Deuxfleurs/garage/pulls/1424 Reviewed-by: Alex <lx@deuxfleurs.fr>
Garage 
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Garage is an S3-compatible distributed object storage service designed for self-hosting at a small-to-medium scale.
Garage is designed for storage clusters composed of nodes running at different physical locations, in order to easily provide a storage service that replicates data at these different locations and stays available even when some servers are unreachable. Garage also focuses on being lightweight, easy to operate, and highly resilient to machine failures.
Garage is built by Deuxfleurs, an experimental small-scale self hosted service provider, which has been using it in production since its first release in 2020.
Learn more on our dedicated documentation pages:
Garage is entirely free software released under the terms of the AGPLv3.