Date: Wed, 11 Mar 2015 00:58:57 -0700 From: Julian Elischer <julian@freebsd.org> To: Xin Li <delphij@delphij.net>, freebsd security <freebsd-security@freebsd.org>, current@freebsd.com Cc: Gregory Shapiro <gshapiro@gshapiro.net> Subject: Re: sendmail broken by libssl in current Message-ID: <54FFF5C1.10909@freebsd.org> In-Reply-To: <54FFEB49.5030706@delphij.net> References: <54FFE774.50103@freebsd.org> <54FFEB49.5030706@delphij.net>
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On 3/11/15 12:14 AM, Xin Li wrote: > > On 3/10/15 23:57, Julian Elischer wrote: >> [sorry for reposting but the original copy I got back had been truncated] >> >> libssl has a new "feature" >> implemented by: >> crypto/openssl/ssl/t1_lib.c >> >> 672 /* Add padding to workaround bugs in F5 terminators. >> 673 * See https://tools.ietf.org/html/draft-agl-tls-padding-03 >> 674 * >> 675 * NB: because this code works out the length of all >> existing >> 676 * extensions it MUST always appear last. >> 677 */ >> 678 //if (s->options & SSL_OP_TLSEXT_PADDING) >> >> unfortunatly this makes sendmail incompatible with various email servers >> around the world, >> including (apparently (ironically (*))) Ironport email gateways. >> It fails in TLS handshake. > I hate workarounds of workarounds :( > > How about this? > > %%% > Index: contrib/sendmail/src/readcf.c > =================================================================== > --- contrib/sendmail/src/readcf.c (revision 279857) > +++ contrib/sendmail/src/readcf.c (working copy) > @@ -116,7 +116,7 @@ readcf(cfname, safe, e) > > #if STARTTLS > Srv_SSL_Options = SSL_OP_ALL; > - Clt_SSL_Options = SSL_OP_ALL > + Clt_SSL_Options = SSL_OP_ALL & ~SSL_OP_TLSEXT_PADDING > #ifdef SSL_OP_NO_SSLv2 > | SSL_OP_NO_SSLv2 > #endif > %%% that's certainly better.. MY change was to just prove where the problem was after reading a bit on the web. The trouble is that that may break mail servers behind F5 appliances. One wonders if one could only turn it off for every second attempt on a retry after a failed attempt. or some other way of not breaking the F5 appliances... I found I could not talk to my child's school (department of education) and my bank, over a period of just a week.. I will look to see if I start picking up new failures now (and see how many F5 appliances there are :-). > Cheers, >
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