Validate required signed headers for both Authorization-header SigV4 requests and presigned URLs. The required signed header set is now `host` plus every incoming header with the `x-amz-` prefix.
During request reconstruction, signed headers and explicitly ignored headers are copied into the generated request used for signature verification. If an incoming `x-amz-*` header is present but missing from the client-provided `SignedHeaders`, return `AccessDenied` with a `HeadersNotSigned` field. The `host` header remains part of the canonical request and signed header calculation.
Previously, a client could sign a request without an S3 control header and then add that header after signing. For example, a presigned `PUT` URL could be generated with only `host` signed, then the actual request could include an unsigned `X-Amz-Tagging` or `X-Amz-Copy-Source` header. Because the verifier reconstructed the request only from `SignedHeaders`, that extra header was omitted from signature calculation and could pass authentication even though it changed the request semantics. This is now rejected with `AccessDenied`.
Expose v4 helper methods for checking required and ignored headers, and update canonical header signing so ignored headers can still be included when a client explicitly lists them in `SignedHeaders`, while `Authorization` remains excluded from signature calculation.
This is a fixup of the codebase using:
go run golang.org/x/tools/go/analysis/passes/modernize/cmd/modernize@latest -fix ./...
This has no bahvior changes, and only updates safe changes for
modern go features.
Fixes#1707
The `Expect` HTTP header is ignored by the AWS SDK SigV4 signer and is omitted during signature calculation. As a result, the signature is computed incorrectly when the `Expect` header is included in the signed headers. This PR removes the `Expect` header from the SigV4 ignored headers list in the SDK-derived source code.
This fixes the case where clients can include the content-length
header in the signed headers for a 0 length file (like s3cmd).
Since we had to hoist the aws code into versitygw, we can also
remove the hack for the "User-Agent" header in the hard coded
excludes list and just remove it from the excludes list.
niksis02
Ben McClelland
jonaustin09