Enforced TLS issue after Postfix upgrade
Hello, After upgrading from 2.5.x to 2.7.1 mail started queuing up to one particular domain (TLS security level: verify) with Server certificate not verified. Systems still on 2.5.x versions of Postfix transmit messages to that domain via enforced TLS just fine. Based on some testing with different version it seems that the change in behavior started with 2.6.0. The ST part of the CN contains an encoded string sequence of \xC3\xBC that represents the German u Umlaut. We have tons of domains setup for enforced TLS and this is the only one that is causing trouble. Warning messages in the log file are also tied to asn1 encoding and eventually CN appears with no value in the log. Which seems to suggest that the asn 1 encoded character is what causes the trouble. Some log information below. Regards, Martin Nov 29 22:14:23 server postfix/smtp[6740]: initializing the client-side TLS engine Nov 29 22:14:24 server postfix/smtp[6740]: setting up TLS connection to mx2.mlp-ag.com[195.170.185.78]:25 Nov 29 22:14:24 server postfix/smtp[6740]: mx2.mlp-ag.com[195.170.185.78]:25: TLS cipher list ALL:!EXPORT:!LOW:+RC4:@STRENGTH:!aNULL Nov 29 22:14:24 server postfix/smtp[6740]: looking for session smtp:195.170.185.78:25:mx2.mlp-ag.comp=1c=ALL:!EXPORT:!LOW:+RC4:@STRENGTH:!aNULL in smtp cache Nov 29 22:14:24 server postfix/smtp[6740]: mx2.mlp-ag.com[195.170.185.78]:25: certificate verification depth=3 verify=1 subject=/C=US/O=VeriSign, Inc./OU=Class 3 Public Primary Certification Authority Nov 29 22:14:24 server postfix/smtp[6740]: mx2.mlp-ag.com[195.170.185.78]:25: certificate verification depth=2 verify=1 subject=/C=US/O=VeriSign, Inc./OU=VeriSign Trust Network/OU=(c) 2006 VeriSign, Inc. - For authorized use only/CN=VeriSign Class 3 Public Primary Certification Authority - G5 Nov 29 22:14:24 server postfix/smtp[6740]: mx2.mlp-ag.com[195.170.185.78]:25: certificate verification depth=1 verify=1 subject=/C=US/O=VeriSign, Inc./OU=VeriSign Trust Network/OU=Terms of use at https://www.verisign.com/rpa (c)06/CN=VeriSign Class 3 Extended Validation SSL SGC CA Nov 29 22:14:24 server postfix/smtp[6740]: mx2.mlp-ag.com[195.170.185.78]:25: certificate verification depth=0 verify=1 subject=/1.3.6.1.4.1.311.60.2.1.3=DE/1.3.6.1.4.1.311.60.2.1.1=Mannheim/2.5.4.15=V1.0, Clause 5.(b)/serialNumber=HRB 335755/C=DE/2.5.4.17=69168/ST=Baden-W\xC3\xBCrttemberg/L=Wiesloch/2.5.4.9=Alte Heerstrasse 40/O=MLP Finanzdienstleistungen Aktiengesellschaft Nov 29 22:14:24 server postfix/smtp[6740]: SSL_connect:SSLv3 read finished A Nov 29 22:14:24 server postfix/smtp[6740]: save session smtp:195.170.185.78:25:mx2.mlp-ag.comp=1c=ALL:!EXPORT:!LOW:+RC4:@STRENGTH:!aNULL to smtp cache Nov 29 22:14:24 server postfix/smtp[6740]: warning: tls_text_name: mx2.mlp-ag.com[195.170.185.78]:25: error decoding peer subject CN of ASN.1 type=12 Nov 29 22:14:24 server postfix/smtp[6740]: warning: TLS library problem: 6740:error:0D07A0A0:asn1 encoding routines:ASN1_mbstring_copy:unknown format:a_mbstr.c:142: Nov 29 22:14:24 server postfix/smtp[6740]: mx2.mlp-ag.com[195.170.185.78]:25: Trusted subject_CN=, issuer_CN=VeriSign Class 3 Extended Validation SSL SGC CA Nov 29 22:14:24 server postfix/smtp[6740]: Trusted TLS connection established to mx2.mlp-ag.com[195.170.185.78]:25: TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits) Nov 29 22:14:24 server postfix/smtp[6740]: 193A714002: Server certificate not verified Nov 29 22:14:25 server postfix/smtp[6740]: setting up TLS connection to mx1.mlp-ag.com[195.170.185.77]:25 Nov 29 22:14:25 server postfix/smtp[6740]: mx1.mlp-ag.com[195.170.185.77]:25: TLS cipher list ALL:!EXPORT:!LOW:+RC4:@STRENGTH:!aNULL Nov 29 22:14:25 server postfix/smtp[6740]: looking for session smtp:195.170.185.77:25:mx1.mlp-ag.comp=1c=ALL:!EXPORT:!LOW:+RC4:@STRENGTH:!aNULL in smtp cache Nov 29 22:14:25 server postfix/smtp[6740]: SSL_connect:before/connect initialization Nov 29 22:14:25 server postfix/smtp[6740]: mx1.mlp-ag.com[195.170.185.77]:25: certificate verification depth=3 verify=1 subject=/C=US/O=VeriSign, Inc./OU=Class 3 Public Primary Certification Authority Nov 29 22:14:25 server postfix/smtp[6740]: mx1.mlp-ag.com[195.170.185.77]:25: certificate verification depth=2 verify=1 subject=/C=US/O=VeriSign, Inc./OU=VeriSign Trust Network/OU=(c) 2006 VeriSign, Inc. - For authorized use only/CN=VeriSign Class 3 Public Primary Certification Authority - G5 Nov 29 22:14:25 server postfix/smtp[6740]: mx1.mlp-ag.com[195.170.185.77]:25: certificate verification depth=1 verify=1 subject=/C=US/O=VeriSign, Inc./OU=VeriSign Trust Network/OU=Terms of use at https://www.verisign.com/rpa (c)06/CN=VeriSign Class 3 Extended Validation SSL SGC CA Nov 29 22:14:25 server postfix/smtp[6740]: mx1.mlp-ag.com[195.170.185.77]:25: certificate verification depth=0 verify=1 subject=/1.3.6.1.4.1.311.60.2.1.3=DE/1.3.6.1.4.1.311.60.2.1.1=Mannheim/2.5.4.15=V1.0, Clause 5.(b)/serialNumber=HRB
Re: Enforced TLS issue after Postfix upgrade
On Tue, Nov 30, 2010 at 02:44:31AM +, Mueller, Martin (Messaging) wrote: After upgrading from 2.5.x to 2.7.1 mail started queuing up to one particular domain (TLS security level: verify) with Server certificate not verified. Postfix TLS support has not changed noticeably since 2.5. Systems still on 2.5.x versions of Postfix transmit messages to that domain via enforced TLS just fine. Based on some testing with different version it seems that the change in behavior started with 2.6.0. What's new in 2.6/2.7 is that finally and with good reason SSLv2 and its associated ciphers are disabled by default. http://www.postfix.org/postconf.5.html#smtp_tls_protocols It is also likely that are you are using a more recent version of OpenSSL, this can be more significant than any minor changes in Postfix. The ST part of the CN contains an encoded string sequence of \xC3\xBC that represents the German u Umlaut. The ST as you say, is not part of the CN it is part of the Distinguished Name or DN. Parts of the DN that are not the CN do not matter for peer verification. We have tons of domains setup for enforced TLS and this is the only one that is causing trouble. Warning messages in the log file are also tied to asn1 encoding and eventually CN appears with no value in the log. Which seems to suggest that the asn 1 encoded character is what causes the trouble. This is almost certainly a Red Herring. initializing the client-side TLS engine setting up TLS connection to mx2.mlp-ag.com[195.170.185.78]:25 mx2.mlp-ag.com[195.170.185.78]:25: TLS cipher list ALL:!EXPORT:!LOW:+RC4:@STRENGTH:!aNULL Your TLS log level is a bit too verbose. Nov 29 22:14:24 server postfix/smtp[6740]: warning: TLS library problem: 6740:error:0D07A0A0:asn1 encoding routines:ASN1_mbstring_copy:unknown format:a_mbstr.c:142: Harmless noise unless you have peername verification turned on. What is the configured TLS security level? Nov 29 22:14:24 server postfix/smtp[6740]: Trusted TLS connection established to mx2.mlp-ag.com[195.170.185.78]:25: TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits) The TLS handshake completes. Nov 29 22:14:24 server postfix/smtp[6740]: 193A714002: Server certificate not verified But you appear to have peername verification turned on. What is your tls security level for this destination? When testing with Postfix 2.7 compiled against OpenSSL 1.0.0a and also 1.0.0b with two patches from the upcoming 1.0.0c (due any day now) everything is normal. Your OpenSSL is perhaps less fortuitously selected than mine. smtp-finger: Connected to mx2.mlp-ag.com[195.170.185.78]:25 smtp-finger: 220 mx2.mlp-ag.com ESMTP smtp-finger: EHLO amnesiac.example.com smtp-finger: 250-mx2.mlp-ag.com smtp-finger: 250-8BITMIME smtp-finger: 250-SIZE 104857600 smtp-finger: 250 STARTTLS smtp-finger: STARTTLS smtp-finger: 220 Go ahead with TLS smtp-finger: mx2.mlp-ag.com[195.170.185.78]:25 Matched CommonName mx2.mlp-ag.com smtp-finger: mx2.mlp-ag.com[195.170.185.78]:25: Matched subject_CN=mx2.mlp-ag.com, issuer_CN=VeriSign Class 3 Extended Validation SSL SGC CA smtp-finger: mx2.mlp-ag.com[195.170.185.78]:25 sha1 fingerprint 90:9A:37:16:7B:DB:5E:D4:0D:72:2F:E4:AA:38:4C:5C:9A:12:59:21 smtp-finger: Verified TLS connection established to mx2.mlp-ag.com[195.170.185.78]:25: TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits) --- Certificate chain 0 s:/1.3.6.1.4.1.311.60.2.1.3=DE/1.3.6.1.4.1.311.60.2.1.1=Mannheim/businessCategory=V1.0, Clause 5.(b)/serialNumber=HRB 335755/C=DE/postalCode=69168/ST=Baden-W\xC3\xBCrttemberg/L=Wiesloch/street=Alte Heerstrasse 40 i:/C=US/O=VeriSign, Inc./OU=VeriSign Trust Network/OU=Terms of use at https://www.verisign.com/rpa (c)06/CN=VeriSign Class 3 Extended Validation SSL SGC CA Certificate: Data: Version: 3 (0x2) Serial Number: 5c:15:d9:5e:08:43:61:e7:6e:40:76:e5:a3:cd:7b:bc Signature Algorithm: sha1WithRSAEncryption Issuer: C=US, O=VeriSign, Inc., OU=VeriSign Trust Network, OU=Terms of use at https://www.verisign.com/rpa (c)06, CN=VeriSign Class 3 Extended Validation SSL SGC CA Validity Not Before: Jul 1 00:00:00 2010 GMT Not After : Jul 1 23:59:59 2011 GMT Subject: 1.3.6.1.4.1.311.60.2.1.3=DE/1.3.6.1.4.1.311.60.2.1.1=Mannheim/businessCategory=V1.0, Clause 5.(b)/serialNumber=HRB 335755, C=DE/postalCode=69168, ST=Baden-W\xC3\xBCrttemberg, L=Wiesloch/street=Alte Heerstrasse 40, O=MLP Finanzdienstleistungen Aktiengesellschaft, OU=e-Services, CN=mx2.mlp-ag.com Subject Public Key Info: Public Key Algorithm: rsaEncryption Public-Key: (2048 bit) Modulus: 00:ba:9e:2d:b9:ea:23:90:d5:a1:28:71:d3:cf:a8: e5:4b:d0:da:2a:00:c4:21:40:8d:77:43:b8:df:73: 49:f9:d2:e8:ae:85:43:74:e1:aa:e2:53:8c:4b:54: 41:0f:b7:62:85:8b:3d:ad:e6:5c:ca:f7:f8:af:4d:
Re: Enforced TLS issue after Postfix upgrade
On Tue, Nov 30, 2010 at 12:56:08AM -0500, Victor Duchovni wrote: When testing with Postfix 2.7 compiled against OpenSSL 1.0.0a and also 1.0.0b with two patches from the upcoming 1.0.0c (due any day now) everything is normal. Your OpenSSL is perhaps less fortuitously selected than mine. I get the same (successfully decoded CN) results with 0.9.8p and Postfix 2.5. I don't have a build of Postfix 2.7 with OpenSSL 0.9.8. What combination are you using? It sounds like your OpenSSL has a problem parsing the CN encoding, this happens very far away from Postfix code, entirely within OpenSSL. -- Viktor.
