https://bugs.exim.org/show_bug.cgi?id=2278
Phil Pennock <p...@exim.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |p...@exim.org --- Comment #2 from Phil Pennock <p...@exim.org> --- DKIM signatures are specified in RFC 6376. --- 3.2. Tag=Value Lists DKIM uses a simple "tag=value" syntax in several contexts, including in messages and domain signature records. [...] Formally, the ABNF syntax rules are as follows: tag-list = tag-spec *( ";" tag-spec ) [ ";" ] tag-spec = [FWS] tag-name [FWS] "=" [FWS] tag-value [FWS] tag-name = ALPHA *ALNUMPUNC tag-value = [ tval *( 1*(WSP / FWS) tval ) ] ; Prohibits WSP and FWS at beginning and end tval = 1*VALCHAR VALCHAR = %x21-3A / %x3C-7E ; EXCLAMATION to TILDE except SEMICOLON ALNUMPUNC = ALPHA / DIGIT / "_" Note that WSP is allowed anywhere around tags. In particular, any WSP after the "=" and any WSP before the terminating ";" is not part of the value; however, WSP inside the value is significant. --- Per the RFC, `b=;` and `b= ;` at the end are equivalent and anything assigning semantic value to the whitespace there, and failing validation, is broken. There's special text in 3.5 around the b= tag in this header for signing, so it's understandable that it's handled specially, but if the issue you highlighted is the root cause, then Exim is fully spec compliant and the verifiers are not. -- You are receiving this mail because: You are on the CC list for the bug. -- ## List details at https://lists.exim.org/mailman/listinfo/exim-dev Exim details at http://www.exim.org/ ##