* iceberg: vend table-scoped credentials to clients that ask for delegation
The catalog recognised X-Iceberg-Access-Delegation: vended-credentials
and then deliberately said nothing, because it had nothing to vend: it
withheld even the S3 endpoint so the client would keep the credentials it
was configured with. That left every engine expecting the catalog to hand
out access - Snowflake, Databricks, Trino with vending, any multi-tenant
setup - needing static S3 keys distributed out of band.
Mint an STS session per request instead, scoped by a session policy to
the table's own prefix plus the bucket listing needed to resolve it, and
return it in the load response config and storage-credentials. The role
to assume is named by -s3.iceberg.credentialRole; its trust policy is
what decides whether a caller may assume it, and vending stays off until
it is set. A failed mint falls back to the old silence rather than
handing back an endpoint the client cannot sign for.
* iceberg: keep vended credentials inside the table prefix
Review follow-ups on credential vending:
Listing was granted on the bucket ARN with no condition, so a credential
vended for one table could enumerate every other table's object names.
Constrain s3:prefix to the table's own prefix, which the S3 gateway
already populates for list requests.
A table location carrying * or ? would have gone into the policy's
resource pattern unescaped and widened the session to sibling prefixes.
Refuse to vend for such a location rather than escaping it; nothing the
catalog generates contains those characters.
DurationSeconds skipped the 900..43200 bounds the other assume-role paths
enforce, so -s3.iceberg.credentialDurationSeconds could ask for a session
outside them. The check is now shared by all three entry points.
* iceberg: return the vended credentials from buildFileIOConfig itself
buildStorageConfig was a second name for what buildFileIOConfig already
did; it now returns the storage credentials alongside the properties, and
callers that only want the properties drop them.
* iceberg: split the vended bucket grants, and refuse a whole-bucket scope
The prefix condition sat on a statement that also granted
GetBucketLocation and ListBucketMultipartUploads, neither of which carries
an s3:prefix to satisfy it, so both were denied for every vended
credential. GetBucketLocation moves to its own unconditioned statement.
ListBucketMultipartUploads is dropped: Iceberg writers complete and abort
by upload id, and granting it either leaks in-flight keys bucket-wide or
breaks on the same missing prefix.
A table whose location has no prefix - one registered at the bucket root -
would have been vended read and write over every other table in the
bucket. Refuse, the way a location with wildcards is refused.
Temporary credentials from STS AssumeRole were using "AKIA" prefix
(permanent IAM user credentials) instead of "ASIA" prefix (temporary
security credentials). This violates AWS conventions and may cause
compatibility issues with AWS SDKs that validate credential types.
Changes:
- Rename generateAccessKeyId to generateTemporaryAccessKeyId for clarity
- Update function to use ASIA prefix for temporary credentials
- Add unit tests to verify ASIA prefix format (weed/iam/sts/credential_prefix_test.go)
- Add integration test to verify ASIA prefix in S3 API (test/s3/iam/s3_sts_credential_prefix_test.go)
- Ensure AWS-compatible credential format (ASIA + 16 hex chars)
The credentials are already deterministic (SHA256-based from session ID)
and the SessionToken is correctly set to the JWT token, so this is just
a prefix fix to follow AWS standards.
Fixes#8312
Chris Lu