fix(exam): source-pdf download reads files row via service role (S4-8.1 merge-gate fix 2)

Pre-merge smoke caught a second issue: the source_file_id download path read `files`
as-the-user, tripping a PRE-EXISTING broken RLS policy on cabinet_memberships
(42P17 infinite recursion). Authz is already enforced (template fetch + source
visibility), and source_file_id is the template's own file, so resolve the row via
service role (documented exception, same as the catalogue lookup). Flagged the
cabinet_memberships RLS recursion separately as infra bug E8.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
This commit is contained in:
CC Worker 2026-06-06 22:54:24 +00:00
parent c0775f3be1
commit a37bcaa935

View File

@ -322,8 +322,12 @@ async def get_template_source_pdf(
except ValueError:
raise HTTPException(status_code=404, detail="Template source not found")
elif template.get("source_file_id"):
# Resolve the file row via service role (authz already done above: the caller proved they
# can see this template, and source_file_id is the template's own file). Reading `files`
# as-the-user trips a pre-existing broken RLS policy on cabinet_memberships
# (42P17 infinite recursion) — documented service-role exception, like the catalogue lookup.
file_row = _first(
ctx.supabase.table("files")
SupabaseServiceRoleClient().supabase.table("files")
.select("bucket, path, mime_type, name")
.eq("id", template["source_file_id"])
.limit(1)