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TLS handshake: Bad certificate - how to solve?

  • 7 प्रत्युत्तर
  • 1 यह समस्या है
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  • के द्वारा अंतिम प्रतियुतर Warren

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Hi, I try to access my email on IMAP mail server running Dovecot v2.3.7.2. It works just fine with any other email client I have tried such as Outlook, Bluemail, Claws, ...

However, when accessing the my email through Thunderbird, it just says "Connecting to... " in the bottom status bar and nothing ever happens - I do not get an error message or any other kind of status update.

In dovecot's mail.log I get these error messages though:

Nov 21 07:55:21 hostxyz dovecot: master: Dovecot v2.3.7.2 (3c910f64b) starting up for imap (core dumps disabled) Nov 21 08:03:46 hostxyz dovecot: imap-login: Disconnected (no auth attempts in 0 secs): user=<>, rip=10.0.0.2, lip=192.168.0.120, TLS handshaking: SSL_accept() failed: error:14094412:SSL routines:ssl3_read_bytes:sslv3 alert bad certificate: SSL alert number 42, session=<Kt6V8kfRD4EKAAAC>

Note that there is a valid non-self-signed server side certificate installed on the mail server. As I don't have a problem accessing email through other clients I assume that something is wrong with my configuration of Thunderbird. Could you please highlight how to configure Thunderbird to make it work again?

Hi, I try to access my email on IMAP mail server running Dovecot v2.3.7.2. It works just fine with any other email client I have tried such as Outlook, Bluemail, Claws, ... However, when accessing the my email through Thunderbird, it just says "Connecting to... " in the bottom status bar and nothing ever happens - I do not get an error message or any other kind of status update. In dovecot's mail.log I get these error messages though: Nov 21 07:55:21 hostxyz dovecot: master: Dovecot v2.3.7.2 (3c910f64b) starting up for imap (core dumps disabled) Nov 21 08:03:46 hostxyz dovecot: imap-login: Disconnected (no auth attempts in 0 secs): user=<>, rip=10.0.0.2, lip=192.168.0.120, TLS handshaking: SSL_accept() failed: error:14094412:SSL routines:ssl3_read_bytes:sslv3 alert bad certificate: SSL alert number 42, session=<Kt6V8kfRD4EKAAAC> Note that there is a valid non-self-signed server side certificate installed on the mail server. As I don't have a problem accessing email through other clients I assume that something is wrong with my configuration of Thunderbird. Could you please highlight how to configure Thunderbird to make it work again?

All Replies (7)

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Hallo, may be you have to import the servers certificate into your Thunderbird or you have to declare an exception. Options -> Safety -> Certificates

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I also have this problem with a CA, server cert, client cert and Dovecot I have generated them using xca and can post the certs and keys if required.

I'm happy to try anything - even nightlys :)

You can't import a certificate into server certificate tab without calling a server.

For the client to fail like this without a word is frustrating - because you have to debug the server to find out what was wrong with Thunderbird.

I tried imap:server:993 in the location box - but it won't load it. and you can't upload one manually into that dialog box.

You can only import your own certificates/keys and CA certificates.


Seamonkey seem worked and Fairmail(Android) works.

ii dovecot-core 1:2.3.4.1-5+deb10u6 amd64 secure POP3/IMAP server - core files

Thunderbird 91.6.0 (64-bit

Using dovecot ssl_min_protocol = TLSv1.2 and all other default.

Debug: SSL: where=0x10, ret=1: before SSL initialization Debug: SSL: where=0x2001, ret=1: before SSL initialization Debug: SSL: where=0x2002, ret=-1: before SSL initialization Debug: SSL: where=0x2001, ret=1: before SSL initialization Debug: SSL: where=0x2001, ret=1: SSLv3/TLS read client hello Debug: SSL: where=0x2001, ret=1: SSLv3/TLS write server hello Debug: SSL: where=0x2001, ret=1: SSLv3/TLS write change cipher spec Debug: SSL: where=0x2001, ret=1: TLSv1.3 write encrypted extensions Debug: SSL: where=0x2001, ret=1: SSLv3/TLS write certificate request Debug: SSL: where=0x2001, ret=1: SSLv3/TLS write certificate Debug: SSL: where=0x10, ret=1: before SSL initialization Debug: SSL: where=0x2001, ret=1: before SSL initialization Debug: SSL: where=0x2002, ret=-1: before SSL initialization Debug: SSL: where=0x2001, ret=1: before SSL initialization Debug: SSL: where=0x2001, ret=1: SSLv3/TLS read client hello Debug: SSL: where=0x2001, ret=1: SSLv3/TLS write server hello Debug: SSL: where=0x2001, ret=1: SSLv3/TLS write change cipher spec Debug: SSL: where=0x2001, ret=1: TLSv1.3 write encrypted extensions Debug: SSL: where=0x2001, ret=1: SSLv3/TLS write certificate request Debug: SSL: where=0x2001, ret=1: SSLv3/TLS write certificate Debug: SSL: where=0x2001, ret=1: TLSv1.3 write server certificate verify Debug: SSL: where=0x2001, ret=1: SSLv3/TLS write finished Debug: SSL: where=0x2001, ret=1: TLSv1.3 early data Debug: SSL: where=0x2002, ret=-1: TLSv1.3 early data Debug: SSL: where=0x2002, ret=-1: TLSv1.3 early data Debug: SSL: where=0x2002, ret=-1: TLSv1.3 early data Debug: SSL: where=0x2001, ret=1: TLSv1.3 write server certificate verify Debug: SSL: where=0x2001, ret=1: SSLv3/TLS write finished Debug: SSL: where=0x2001, ret=1: TLSv1.3 early data Debug: SSL: where=0x2002, ret=-1: TLSv1.3 early data Debug: SSL: where=0x2002, ret=-1: TLSv1.3 early data Debug: SSL: where=0x2002, ret=-1: TLSv1.3 early data Debug: SSL: where=0x2002, ret=-1: TLSv1.3 early data Debug: SSL alert: where=0x4004, ret=554: fatal bad certificate Debug: SSL: where=0x2002, ret=-1: error Debug: SSL error: SSL_accept() failed: error:14094412:SSL routines:ssl3_read_bytes:sslv3 alert bad certificate: SSL alert number 42 Disconnected (no auth attempts in 1 secs): user=<>, rip=10.8.0.10, lip=10.8.0.1, TLS handshaking: SSL_accept() failed: error:14094412:SSL routines:ssl3_read_bytes:sslv3 alert bad certificate: SSL alert number 42, session=<Bbx/lCzYvIYKCAAK>

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Is there anything related in the TB error console (Ctrl-Shift-J)?

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Ok - I finnally found a log mechanism - https://searchfox.org/comm-central/search?q=LazyLogModule

export MOZ_LOG_FILE=/tmp/imap.log export MOZ_LOG=pipnss:5

And snarfed the log - but I can't upload it so I'll just paste it in here.

Arrrh -- Ensure this value has at most 10000 characters (it has 10081). :)

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[Parent 1229825: Main Thread]: D/pipnss nsNSSComponent::ctor [Parent 1229825: Main Thread]: D/pipnss Beginning NSS initialization [Parent 1229825: Main Thread]: D/pipnss nsNSSComponent::InitializeNSS [Parent 1229825: Main Thread]: D/pipnss NSS Initialization beginning [Parent 1229825: Main Thread]: D/pipnss NSS profile at '/home/wozza/.thunderbird/uqeiznj0.default' [Parent 1229825: Main Thread]: D/pipnss not setting NSS_SDB_USE_CACHE [Parent 1229825: Main Thread]: D/pipnss inSafeMode: 0 [Parent 1229825: Main Thread]: D/pipnss initialized NSS in r/w mode [Parent 1229825: Main Thread]: D/pipnss NSS Initialization done [Parent 1229825: Main Thread]: D/pipnss nsNSSComponent: adding observers [Parent 1229825: Main Thread]: D/pipnss nsNSSComponent::MaybeEnableIntermediatePreloadingHealer [Parent 1229825: StreamTrans #1]: D/pipnss loaded CKBI from /usr/lib/x86_64-linux-gnu [Parent 1229825: Socket Thread]: D/pipnss [7fb8b9bfb910] nsSSLIOLayerSetOptions: using TLS version range (0x0301,0x0304) [Parent 1229825: Socket Thread]: D/pipnss [7fb8b9bfb910] Socket set up [Parent 1229825: Socket Thread]: D/pipnss [7fb8b9bfb910] connecting SSL socket [Parent 1229825: Socket Thread]: E/pipnss [7fb8b9bfb910] Lower layer connect error: -5934 [Parent 1229825: Socket Thread]: D/pipnss [7fb8b9bfbdf0] nsSSLIOLayerSetOptions: using TLS version range (0x0301,0x0304) [Parent 1229825: Socket Thread]: D/pipnss [7fb8b9bfbdf0] Socket set up [Parent 1229825: Socket Thread]: D/pipnss [7fb8b9bfbdf0] connecting SSL socket [Parent 1229825: Socket Thread]: E/pipnss [7fb8b9bfbdf0] Lower layer connect error: -5934 [Parent 1229825: Socket Thread]: D/pipnss [7fb8ccb89550] nsSSLIOLayerSetOptions: using TLS version range (0x0301,0x0304) [Parent 1229825: Socket Thread]: D/pipnss [7fb8ccb89550] Socket set up [Parent 1229825: Socket Thread]: D/pipnss [7fb8ccb89550] connecting SSL socket [Parent 1229825: Socket Thread]: E/pipnss [7fb8ccb89550] Lower layer connect error: -5934 [Parent 1229825: Socket Thread]: V/pipnss [7fb8b9bfbdf0] read -1 bytes [Parent 1229825: Socket Thread]: V/pipnss [7fb8b9bfb910] read -1 bytes [Parent 1229825: Socket Thread]: V/pipnss [7fb8ccb89550] read -1 bytes [Parent 1229825: Socket Thread]: V/pipnss [7fb8ccb89550] wrote -1 bytes [Parent 1229825: Socket Thread]: V/pipnss [7fb8ccb89550] wrote -1 bytes [Parent 1229825: Socket Thread]: V/pipnss [7fb8ccb89550] read -1 bytes [Parent 1229825: Socket Thread]: V/pipnss [7fb8ccb89550] wrote -1 bytes [Parent 1229825: Socket Thread]: V/pipnss [7fb8ccb89550] read -1 bytes [Parent 1229825: Socket Thread]: D/pipnss [7fb8ccb89400] starting AuthCertificateHook [Parent 1229825: Socket Thread]: D/pipnss [7fb8ccb89400] starting AuthCertificateHookInternal [Parent 1229825: SSL Cert #1]: D/pipnss [7fb8ccb89400] SSLServerCertVerificationJob::Run [Parent 1229825: Socket Thread]: V/pipnss [7fb8ccb89550] wrote -1 bytes [Parent 1229825: Socket Thread]: V/pipnss [7fb8ccb89550] read -1 bytes [Parent 1229825: Socket Thread]: V/pipnss [7fb8ccb89550] polling SSL socket during certificate verification using lower 5 [Parent 1229825: Socket Thread]: V/pipnss [7fb8ccb89550] polling SSL socket during certificate verification using lower 6 [Parent 1229825: Socket Thread]: D/pipnss AuthCertificate setting NEW cert 7fb8b28e6e20 [Parent 1229825: Socket Thread]: D/pipnss [7fb8ccb89400] HandshakeCallback: succeeded using TLS version range (0x0301,0x0304) [Parent 1229825: Socket Thread]: D/pipnss HandshakeCallback KEEPING existing cert [Parent 1229825: Socket Thread]: D/pipnss [7fb8ccb89550] nsNSSSocketInfo::NoteTimeUntilReady [Parent 1229825: Socket Thread]: D/pipnss [7fb8ccb89550] nsNSSSocketInfo::SetHandshakeCompleted [Parent 1229825: Socket Thread]: V/pipnss [7fb8ccb89550] wrote 137 bytes [Parent 1229825: Socket Thread]: V/pipnss [7fb8b9bfb910] read -1 bytes [Parent 1229825: Socket Thread]: D/pipnss [7fb8b9bfbc10] starting AuthCertificateHook [Parent 1229825: Socket Thread]: D/pipnss [7fb8b9bfbc10] starting AuthCertificateHookInternal [Parent 1229825: SSL Cert #1]: D/pipnss [7fb8b9bfbc10] SSLServerCertVerificationJob::Run [Parent 1229825: SSL Cert #1]: D/pipnss [0x7fb8b9bfbc10] Certificate error was not overridden [Parent 1229825: Main Thread]: D/pipnss FindClientCertificatesWithPrivateKeys [Parent 1229825: Main Thread]: D/pipnss module 'NSS Internal PKCS #11 Module' [Parent 1229825: Main Thread]: D/pipnss slot 'NSS Internal Cryptographic Services' [Parent 1229825: Main Thread]: D/pipnss (looking at non-internal slot) [Parent 1229825: Main Thread]: D/pipnss slot 'NSS User Private Key and Certificate Services' [Parent 1229825: Main Thread]: D/pipnss (looking at internal slot) [Parent 1229825: Main Thread]: D/pipnss provisionally adding 'E=warren@itcl.com.au,CN=warrenc5' [Parent 1229825: Main Thread]: D/pipnss module 'Builtin Roots Module' [Parent 1229825: Main Thread]: D/pipnss slot 'NSS Builtin Objects' [Parent 1229825: Main Thread]: D/pipnss (looking at non-internal slot) [Parent 1229825: Main Thread]: D/pipnss returning: [Parent 1229825: Main Thread]: D/pipnss E=warren@itcl.com.au,CN=warrenc5 [Parent 1229825: Main Thread]: D/pipnss keeping cert 'E=warren@itcl.com.au,CN=warrenc5' [Parent 1229825: Socket Thread]: V/pipnss [7fb8b9bfb910] read -1 bytes [Parent 1229825: Socket Thread]: V/pipnss [7fb8b9bfb910] polling SSL socket during certificate verification using lower 5 [Parent 1229825: Socket Thread]: V/pipnss [7fb8b9bfb910] polling SSL socket during certificate verification using lower 5 [Parent 1229825: Socket Thread]: D/pipnss [7fb8b9bfbe20] starting AuthCertificateHook [Parent 1229825: Socket Thread]: D/pipnss [7fb8b9bfbe20] starting AuthCertificateHookInternal [Parent 1229825: SSL Cert #1]: D/pipnss [7fb8b9bfbe20] SSLServerCertVerificationJob::Run [Parent 1229825: SSL Cert #1]: D/pipnss [0x7fb8b9bfbe20] Certificate error was not overridden [Parent 1229825: Main Thread]: D/pipnss FindClientCertificatesWithPrivateKeys [Parent 1229825: Main Thread]: D/pipnss module 'NSS Internal PKCS #11 Module' [Parent 1229825: Main Thread]: D/pipnss slot 'NSS Internal Cryptographic Services' [Parent 1229825: Main Thread]: D/pipnss (looking at non-internal slot) [Parent 1229825: Main Thread]: D/pipnss slot 'NSS User Private Key and Certificate Services' [Parent 1229825: Main Thread]: D/pipnss (looking at internal slot) [Parent 1229825: Main Thread]: D/pipnss provisionally adding 'E=warren@itcl.com.au,CN=warrenc5' [Parent 1229825: Main Thread]: D/pipnss module 'Builtin Roots Module' [Parent 1229825: Main Thread]: D/pipnss slot 'NSS Builtin Objects' [Parent 1229825: Main Thread]: D/pipnss (looking at non-internal slot) [Parent 1229825: Main Thread]: D/pipnss returning: [Parent 1229825: Main Thread]: D/pipnss E=warren@itcl.com.au,CN=warrenc5 [Parent 1229825: Main Thread]: D/pipnss keeping cert 'E=warren@itcl.com.au,CN=warrenc5' [Parent 1229825: Socket Thread]: V/pipnss [7fb8b9bfbdf0] read -1 bytes [Parent 1229825: Socket Thread]: V/pipnss [7fb8ccb89550] read 140 bytes [Parent 1229825: Socket Thread]: V/pipnss [7fb8ccb89550] read 197 bytes [Parent 1229825: Socket Thread

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Digging a little deeper to try and get the CertificateVerify result from TB but cant.

is 42 error that dovecot reports this error code here?

https://searchfox.org/mozilla-central/source/security/nss/lib/mozpkix/include/pkix/Result.h#88

MOZILLA_PKIX_MAP(ERROR_BAD_CERT_DOMAIN, 42, SSL_ERROR_BAD_CERT_DOMAIN)

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So to follow up - I got it working by getting the certificate in the certificate manager through the https server I set up (apache - default ssl)

Then manually editing the overrides file ~/.thunderbird/uqeiznj0.default/cert_override.txt and changing the first field from www.itcl.com.au:443 to mail.itcl.com.au:993

It would just be a lot easier to add an exception with the certificate file in the user interface.

I will further investigate how to manually construct this file from the raw certificate details ...

Then you can just write your own exceptions.