* s3api: verify source permission on CopyObject and UploadPartCopy
The Auth middleware only authorized the destination because routes key on
the request URL. The source from X-Amz-Copy-Source was never evaluated,
so an STS session token scoped to one prefix could copy from any other
prefix in the same bucket.
Add AuthorizeCopySource on IdentityAccessManagement to run the full
bucket-policy + IAM/identity flow against the source, using a synthetic
GetObject request so action resolution lands on s3:GetObject (or
s3:GetObjectVersion when a source versionId is supplied). Both
CopyObjectHandler and CopyObjectPartHandler now invoke it before reading
the source.
* s3api: preserve presigned-URL session token on copy-source check
Presigned CopyObject / UploadPartCopy requests carry the STS session
token in the query string (X-Amz-Security-Token), not in a header.
Rebuilding the synthetic source URL from scratch dropped that token, so
the source authorization would fall through to non-STS paths and miss
session policy enforcement. Forward X-Amz-Security-Token from the
original query (alongside versionId), still excluding unrelated params
like uploadId/partNumber that would steer ResolveS3Action away from
s3:GetObject.
see https://blog.aqwari.net/xml-schema-go/
1. go get aqwari.net/xml/cmd/xsdgen
2. Add EncodingType element for ListBucketResult in AmazonS3.xsd
3. xsdgen -o s3api_xsd_generated.go -pkg s3api AmazonS3.xsd
4. Remove empty Grantee struct in s3api_xsd_generated.go
5. Remove xmlns: sed s'/http:\/\/s3.amazonaws.com\/doc\/2006-03-01\/\ //' s3api_xsd_generated.go
c61d227613