The r3 fold scoped only the dmarc verdict to its clause. SPF and DKIM
still came from a whole-string, last-match-wins regex scan, so the same
quoted/comment smuggle closed for dmarc still authenticated a spoofed
From (GHSA-rxqh-5572-8m77), e.g.
spf=fail smtp.mailfrom="x spf=pass smtp.mailfrom=example.com "@evil.test
spf=fail (spf=pass) smtp.mailfrom=a@example.com
spf=fail smtp.mailfrom=a.spf=pass@example.com
dkim=pass header.d=evil.test header.i="x header.d=example.com y"@evil.test
Every verdict now comes from the leading method=result token of its
own clause (from _ar_clauses, comments dropped), and its domains only
from that clause. Properties are read by a token scanner that consumes
quoted-strings and other key=value tokens whole, so quoted contents are
never read as properties while a quoted value still is
(header.from="example.com"). SPF fails closed on more than one spf
clause; DKIM accepts any single dkim=pass clause whose own header.d
aligns (multi-signature mail is normal), never mixing clauses. The
whole-string methods/props (methods["dmarc"] was dead) are gone.
Also: a stray ')' at depth 0 is now unbalanced (it split header.from
out of the dmarc clause); a From with more than 64 '(' takes the silent
empty-sender drop instead of a parseaddr RecursionError logged as an
error; the cap test asserts the cap directly instead of wall-clock
timing; the empty-From drop assertion moves next to the other
_extract_email_address rejects; and the untested >1-dmarc, unbalanced
and backslash-escape rules get reject strings.
3f4533b9de