WorkflowCatalog._fetch_single_catalog and StepCatalog._fetch_single_catalog
opened the catalog URL with open_url(entry.url, timeout=30) and validated
only the final resp.geturl(). open_url follows redirects, so an https://
catalog entry that 30x-redirects through a non-HTTPS host mid-chain could
let a network attacker rewrite the next hop and slip a payload past the
terminal-URL-only check. The payload then drives step/workflow catalog data.
Pass a redirect_validator that runs the existing HTTPS/hostname check before
every redirect hop, keeping the final geturl() check as a defense-in-depth
backstop. This brings both workflow catalog loaders to parity with the
presets (#3523) and extensions (#3524) catalog fetchers.
Tests: add per-hop redirect-validation tests for both WorkflowCatalog and
StepCatalog (a non-HTTPS intermediate hop is rejected); both fail before the
fix ("NoneType object is not callable" — no validator passed). Update the two
existing malformed-redirect tests whose open_url stub lacked the
redirect_validator kwarg.
30e99ec083