[ietf-dkim] LWSP in base64-encoded public key TXT RR
Mark.Martinec+dkim at ijs.si
Wed Mar 7 00:34:45 PST 2007
I came across a real life example where a public key as returned
by a DNS record contained embedded CR LF, probably due to a
misconfiguration or a broken DNS server implementation.
Two different DKIM implementations gave different treatment to the
situation, one claiming 'key syntax error', the other accepted it.
Turning to draft-ietf-dkim-base-10 reveals:
key-p-tag = %x70 [FWS] "=" [ [FWS] base64string ]
base64string = 1*(ALPHA / DIGIT / "+" / "/" / LWSP)
[ "=" LWSP [ "=" LWSP ] ]
LWSP = *(WSP / CRLF WSP)
which would indicate that a public key in TXT RR
like the following would be alright:
while the one without a <SP> would not be syntactically correct:
It seems the requirement to insist on LWSP (e.g. a WSP must follow CRLF)
in a non- message header context is very much artificial and unwarranted.
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