Hi Jiajia, Forward one of my discussion thread, https://lists.apache.org/thread/jgwhzmvvdfr1mc7nfdrtp7btrmt9wdqx. In general, forwarding the remote's storage credentials breaks the Polaris security model. We should avoid that if possible.
Best, Yufei On Tue, Aug 18, 2026 at 11:51 PM Jiajia Li <[email protected]> wrote: > Hi all, > Raising this from PR #5309, at @vigneshio's suggestion. The PR also > changes the management API — roleArn is no longer required on > SigV4AuthenticationParameters, plus new accessKeyId and secretAccessKey > fields — so comments on that are welcome too. > A federated catalog mints storage credentials from its own > storageConfigInfo. When the remote catalog owns the storage there is no > local configuration describing it, and every route fails: vending is > refused, or validateTableLocations rejects the remote's locations, or > allowedLocations is rejected at create time over the > URI scheme. The client can't work around it either when the remote only > honours credentials it issued. > I have an opt-in per-catalog flag that forwards the remote's credentials > instead, read off the loaded table's FileIO via SupportsStorageCredentials. > It refuses principals not authorized for write delegation, since forwarded > credentials are scoped to the identity Polaris federates with and can't be > narrowed to the caller. > Verified end to end: a stock Iceberg client with no storage credentials > of its own read a table through Polaris. > The question is the trust model. On this path Polaris stops being the > location policy point — validateTableLocations is skipped, because it > compares against storage this deployment configured rather than what's > being handed out. As @vigneshio put it, "the remote scoped the creds" is > only as strong as our trust in that > remote. Per-catalog opt-in is the best answer I have; if there's a > meaningful location check to keep here, I'd rather have it. > If the list would rather Polaris not take this on, that's a useful answer > too — the alternative is engines talking to these catalogs directly and > skipping federation. > Thanks, > Jiajia > Thanks, > Jiajia >
