Android 6.0 uses BoringSSL which enforces a minimum default DiffieHelman length 
(BAD_DH_P_LENGTH) to mitigate the LogJam attack. 

I would guess that Gmail disables this. We probably could but we don't. I'm not 
sure it's a good idea. 

We have existing issues open to improve the errors we give - I'll make sure 
this instance is covered. 

I think upgrading the software your email server runs should fix this - the 
servers use some default parameters I believe. 

If you wanted to change your setup you definitely could improve it - e.g. SSLv3 
is broken and all clients should refuse to use it. 


On April 14, 2016 7:36:21 AM GMT+01:00, Joa H <[email protected]> wrote:
>Hi
>
>K-9 won´t connect after upgrading to Android 6.0, I get the below 
>exception. This didn't happen before. Incidentally MailWise also does
>not 
>work since then. I tried Gmail and that works, so I'm not sure where
>the 
>problem lies. I've tried to find something on this problem, but haven't
>
>found much. There are suggestions that it might be the server not 
>supporting necessary protocols or cipher suites, but why then does
>Gmail 
>work?
>
>My IMAP server has a (since 2011 expired) self signed certificate
>(which 
>worked fine til now). An SSL check reveals that TLS1.0 and SSLv3 are 
>supported and the following ciphers:
>TLS_RSA_EXPORT_WITH_RC4_40_MD5 (0x0003)
>TLS_RSA_WITH_RC4_128_MD5 (0x0004)
>TLS_RSA_WITH_RC4_128_SHA (0x0005)
>TLS_RSA_EXPORT_WITH_DES40_CBC_SHA (0x0008)
>TLS_RSA_WITH_DES_CBC_SHA (0x0009)
>TLS_RSA_WITH_3DES_EDE_CBC_SHA (0x000A)
>TLS_DHE_RSA_EXPORT_WITH_DES40_CBC_SHA (0x0014)
>TLS_DHE_RSA_WITH_DES_CBC_SHA (0x0015)
>TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA (0x0016)
>TLS_RSA_WITH_AES_128_CBC_SHA (0x002F)
>TLS_DHE_RSA_WITH_AES_128_CBC_SHA (0x0033)
>
>I would be grateful for any tips.
>
>The exception:
>
>K9-Mail version: 5.010
>Device make: Sony
>Device model: E6653
>Android version: 6.0
>
>com.fsck.k9.mail.MessagingException: IO Error
>       at
>com.fsck.k9.mail.store.ImapStore$ImapFolder.ioExceptionHandler(ImapStore.java:2208)
>       at
>com.fsck.k9.mail.store.ImapStore$ImapFolder.internalOpen(ImapStore.java:947)
>       at
>com.fsck.k9.mail.store.ImapStore$ImapFolder.open(ImapStore.java:867)
>       at
>com.fsck.k9.controller.MessagingController.synchronizeMailboxSynchronous(MessagingController.java:1041)
>       at
>com.fsck.k9.controller.MessagingController.access$400(MessagingController.java:111)
>       at
>com.fsck.k9.controller.MessagingController$8.run(MessagingController.java:934)
>       at
>com.fsck.k9.controller.MessagingController.run(MessagingController.java:435)
>       at java.lang.Thread.run(Thread.java:818)
>Caused by: javax.net.ssl.SSLHandshakeException: Handshake failed
>       at
>com.android.org.conscrypt.OpenSSLSocketImpl.startHandshake(OpenSSLSocketImpl.java:396)
>       at
>com.android.org.conscrypt.OpenSSLSocketImpl.waitForHandshake(OpenSSLSocketImpl.java:629)
>       at
>com.android.org.conscrypt.OpenSSLSocketImpl.getInputStream(OpenSSLSocketImpl.java:591)
>       at
>com.fsck.k9.mail.store.ImapStore$ImapConnection.open(ImapStore.java:2460)
>       at
>com.fsck.k9.mail.store.ImapStore$ImapConnection.sendCommand(ImapStore.java:2872)
>       at
>com.fsck.k9.mail.store.ImapStore$ImapConnection.executeSimpleCommand(ImapStore.java:2921)
>       at
>com.fsck.k9.mail.store.ImapStore$ImapConnection.executeSimpleCommand(ImapStore.java:2902)
>       at
>com.fsck.k9.mail.store.ImapStore$ImapFolder.executeSimpleCommand(ImapStore.java:858)
>       at
>com.fsck.k9.mail.store.ImapStore$ImapFolder.internalOpen(ImapStore.java:904)
>       ... 6 more
>Caused by: javax.net.ssl.SSLProtocolException: SSL handshake aborted:
>ssl=0x7f41039300: Failure in SSL library, usually a protocol error
>error:100c1069:SSL
>routines:ssl3_get_server_key_exchange:BAD_DH_P_LENGTH
>(external/boringssl/src/ssl/s3_clnt.c:1193 0x7f73563518:0x00000000)
>       at com.android.org.conscrypt.NativeCrypto.SSL_do_handshake(Native
>Method)
>       at
>com.android.org.conscrypt.OpenSSLSocketImpl.startHandshake(OpenSSLSocketImpl.java:324)
>       ... 14 more
>
>
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>To unsubscribe, email [email protected]
>To report an issue with K-9 Mail, visit
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>
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Best regards,

Philip Whitehouse

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To post to this group, send email to [email protected]
To unsubscribe, email [email protected]
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