* s3: test the GetCallerIdentity handler
The handler had no test, only XML marshalling, so nothing pinned that a
caller presenting session credentials is reported as the assumed role
rather than the user who minted the session.
* s3: drive AssumeRoleWithWebIdentity over HTTP with a real OIDC token
Coverage reached the OIDC path either at the IAMManager service layer or
through the Authorization: Bearer shortcut. Nothing exercised the public
STS entry point an AWS SDK actually calls, which is where parameter
parsing, the IAMManager dispatch and the XML response shape live.
* s3: test that every STS route emits an audit entry
STS responses go out through WriteXMLResponse, which never calls PostLog,
so track() is the only thing that logs them. A route registered outside it
would mint credentials with no audit trail and nothing would notice. STS
has three routing layers, so a new action is easy to attach to the wrong
one.
* s3: make the STS tests assert what they claim to cover
The audit routing test ran against an uninitialized STS service, so every
case answered 503 and a non-404 status was the only evidence the request
had reached STS at all - the POST-body case could have been served by the
dispatcher's IAM branch and still passed. Back it with a real STS service
and assert the STS response namespace, which IAM and S3 responses do not
carry.
The session policy case checked that the policy travelled in the token
rather than that it restricted anything; assert the narrowed bucket is
allowed and another bucket is refused.
Give the forged-token case the same claim set a valid token gets, so it
cannot pass for want of a claim, and cover both rejection paths: a key we
do not publish, and a key id absent from the JWKS.
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