mathiasandClaude Sonnet 5
4f75279ceb
Round-4 review found a fifth bypass, and this one needs no adversarial
old_str/new_str crafting at all: frontmatterBlock's fence detection matches
the literal byte sequence "---\n". A note whose fence lines use CRLF
("---\r\n") fails strings.HasPrefix(doc, "---\n") on the precondition read
purely from line-ending encoding — hadFence is false, so the round-3/round-4
checks can never fire, frontmatterScalars falls back to an empty map, and
claim.ValidateEnvelope({}) is nil by design. An invalid claim_provenance
value lands with zero error.
Zero CRLF-fenced notes exist in the live corpus today, but nothing in the
code prevented one, and this class of encoding-dependent false negative
could resurface in any of the other fence-based checks. Normalize once
inside frontmatterBlock so every caller (fence-presence detection and
frontmatterScalars) agrees regardless of line ending.
The broader structural concern — three independent, subtly inconsistent
fence-parsing implementations across internal/mcp, internal/api, and
internal/frontmatter, of which this CRLF gap is a direct symptom — is out
of scope for this PR and filed separately as hyperguild#138.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>