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I am running Ubuntu Server 20.04 and proftpd 1.36 and have an issue setting up TLS.

I have followed the guide in the config file, but I get a very odd error. That there is no supported cipher. And then the process breaks with a handshake error. The SSL clienthello message includes a lot of ciphers that is recognised, and that is on the machine.

TLS log:

2020-06-29 18:16:30,457 mod_tls/2.7[87378]: [stat]: SSL sessions attempted: 0
2020-06-29 18:16:30,457 mod_tls/2.7[87378]: [stat]: SSL sessions established: 0
2020-06-29 18:16:30,457 mod_tls/2.7[87378]: [stat]: SSL sessions renegotiated: 0
2020-06-29 18:16:30,457 mod_tls/2.7[87378]: [stat]: SSL sessions resumed: 0
2020-06-29 18:16:30,457 mod_tls/2.7[87378]: [stat]: SSL sessions in cache: 0
2020-06-29 18:16:30,457 mod_tls/2.7[87378]: [stat]: SSL session cache hits: 0
2020-06-29 18:16:30,457 mod_tls/2.7[87378]: [stat]: SSL session cache misses: 0
2020-06-29 18:16:30,457 mod_tls/2.7[87378]: [stat]: SSL session cache timeouts: 0
2020-06-29 18:16:30,457 mod_tls/2.7[87378]: [stat]: SSL session cache size exceeded: 0
2020-06-29 18:16:35,242 mod_tls/2.7[87910]: TLSOption EnableDiags enabled, setting diagnostics callback
2020-06-29 18:16:35,245 mod_tls/2.7[87910]: error initializing OpenSSL context for this session
2020-06-29 18:16:35,247 mod_tls/2.7[87910]: TLS/TLS-C requested, starting TLS handshake
2020-06-29 18:16:35,247 mod_tls/2.7[87910]: [info] (unknown): before SSL initialization
2020-06-29 18:16:35,247 mod_tls/2.7[87910]: [info] accepting: before SSL initialization
2020-06-29 18:16:35,247 mod_tls/2.7[87910]: [info] accepting: before SSL initialization
2020-06-29 18:16:35,255 mod_tls/2.7[87910]: [msg] received protocol record message (5 bytes)
2020-06-29 18:16:35,255 mod_tls/2.7[87910]: [info] accepting: before SSL initialization
2020-06-29 18:16:35,255 mod_tls/2.7[87910]: [msg] received TLSv1.3 'ClientHello' Handshake message (368 bytes)
2020-06-29 18:16:35,256 mod_tls/2.7[87910]: [msg]
ClientHello:
  client_version = TLS 1.2
  random:
    gmt_unix_time = Thu Oct 20 14:46:18 1904 (not guaranteed to be accurate)
    random_bytes (28 bytes)
      5820ebe66e5afa9ec7d9cfc5d69fd7b97698ba054091bd338c918587
  session_id (0 bytes)
  cipher_suites (58 bytes)
    TLS_AES_256_GCM_SHA384
    TLS_CHACHA20_POLY1305_SHA256
    TLS_AES_128_GCM_SHA256
    [unknown/unsupported]
    TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
    [unknown/unsupported]
    TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
    [unknown/unsupported]
    TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
    TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
    [unknown/unsupported]
    TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
    [unknown/unsupported]

    TLS_RSA_WITH_AES_256_CBC_SHA
    [unknown/unsupported]
    TLS_RSA_WITH_AES_128_GCM_SHA256
    TLS_RSA_WITH_AES_128_CBC_SHA
    [unknown/unsupported]
    TLS_DHE_RSA_WITH_AES_256_GCM_SHA384
    [unknown/unsupported]
    TLS_DHE_RSA_WITH_AES_256_CBC_SHA
    [unknown/unsupported]
    TLS_DHE_RSA_WITH_AES_128_GCM_SHA256
    TLS_DHE_RSA_WITH_AES_128_CBC_SHA
    [unknown/unsupported]
  compression_methods (1 byte)
    None
  extensions (265 bytes)
    extension_type = status_request (5 bytes)
    extension_type = elliptic_curves (22 bytes)
    extension_type = ec_point_formats (2 bytes)
    extension_type = signature_algorithms (34 bytes)
    extension_type = encrypt_then_mac (0 bytes)
    extension_type = extended_master_secret (0 bytes)
    extension_type = session_ticket (0 bytes)
    extension_type = key_share (139 bytes)
    extension_type = supported_versions (9 bytes)
    extension_type = renegotiate (1 byte)
    extension_type = psk_kex_modes (3 bytes)
    extension_type = [unknown/unsupported] (2 bytes)

2020-06-29 18:16:35,256 mod_tls/2.7[87910]: [msg] sent protocol record message (5 bytes)
2020-06-29 18:16:35,256 mod_tls/2.7[87910]: [msg] sent TLSv1.2 fatal 'handshake_failure' Alert message (2 bytes)
2020-06-29 18:16:35,256 mod_tls/2.7[87910]: [info] writing: SSL/TLS alert fatal: handshake failure
2020-06-29 18:16:35,256 mod_tls/2.7[87910]: [info] accepting: error
2020-06-29 18:16:35,256 mod_tls/2.7[87910]: unable to accept TLS connection: protocol error:
  (1) error:1417A0C1:SSL routines:tls_post_process_client_hello:no shared cipher
2020-06-29 18:16:35,256 mod_tls/2.7[87910]: unable to accept TLS connection: client does not support any cipher from 'TLSCipherSuite DEFAULT:!ADH:!EXPORT:!DES' (see `openssl ciphers DE>
2020-06-29 18:16:35,256 mod_tls/2.7[87910]: TLS/TLS-C negotiation failed on control channel
2020-06-29 18:16:35,256 mod_tls/2.7[87910]: [stat]: SSL sessions attempted: 1
2020-06-29 18:16:35,256 mod_tls/2.7[87910]: [stat]: SSL sessions established: 0
2020-06-29 18:16:35,256 mod_tls/2.7[87910]: [stat]: SSL sessions renegotiated: 0
2020-06-29 18:16:35,256 mod_tls/2.7[87910]: [stat]: SSL sessions resumed: 0
2020-06-29 18:16:35,256 mod_tls/2.7[87910]: [stat]: SSL sessions in cache: 0
2020-06-29 18:16:35,256 mod_tls/2.7[87910]: [stat]: SSL session cache hits: 0
2020-06-29 18:16:35,256 mod_tls/2.7[87910]: [stat]: SSL session cache misses: 0
2020-06-29 18:16:35,256 mod_tls/2.7[87910]: [stat]: SSL session cache timeouts: 0
2020-06-29 18:16:35,256 mod_tls/2.7[87910]: [stat]: SSL session cache size exceeded: 0

Output of openssl

openssl ciphers -v 'DEFAULT:!ADH:!EXPORT:!DES'
TLS_AES_256_GCM_SHA384  TLSv1.3 Kx=any      Au=any  Enc=AESGCM(256) Mac=AEAD
TLS_CHACHA20_POLY1305_SHA256 TLSv1.3 Kx=any      Au=any  Enc=CHACHA20/POLY1305(256) Mac=AEAD
TLS_AES_128_GCM_SHA256  TLSv1.3 Kx=any      Au=any  Enc=AESGCM(128) Mac=AEAD
ECDHE-ECDSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH     Au=ECDSA Enc=AESGCM(256) Mac=AEAD
ECDHE-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH     Au=RSA  Enc=AESGCM(256) Mac=AEAD
DHE-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=DH       Au=RSA  Enc=AESGCM(256) Mac=AEAD
ECDHE-ECDSA-CHACHA20-POLY1305 TLSv1.2 Kx=ECDH     Au=ECDSA Enc=CHACHA20/POLY1305(256) Mac=AEAD
ECDHE-RSA-CHACHA20-POLY1305 TLSv1.2 Kx=ECDH     Au=RSA  Enc=CHACHA20/POLY1305(256) Mac=AEAD
DHE-RSA-CHACHA20-POLY1305 TLSv1.2 Kx=DH       Au=RSA  Enc=CHACHA20/POLY1305(256) Mac=AEAD
ECDHE-ECDSA-AES128-GCM-SHA256 TLSv1.2 Kx=ECDH     Au=ECDSA Enc=AESGCM(128) Mac=AEAD
ECDHE-RSA-AES128-GCM-SHA256 TLSv1.2 Kx=ECDH     Au=RSA  Enc=AESGCM(128) Mac=AEAD
DHE-RSA-AES128-GCM-SHA256 TLSv1.2 Kx=DH       Au=RSA  Enc=AESGCM(128) Mac=AEAD
ECDHE-ECDSA-AES256-SHA384 TLSv1.2 Kx=ECDH     Au=ECDSA Enc=AES(256)  Mac=SHA384
ECDHE-RSA-AES256-SHA384 TLSv1.2 Kx=ECDH     Au=RSA  Enc=AES(256)  Mac=SHA384
DHE-RSA-AES256-SHA256   TLSv1.2 Kx=DH       Au=RSA  Enc=AES(256)  Mac=SHA256
ECDHE-ECDSA-AES128-SHA256 TLSv1.2 Kx=ECDH     Au=ECDSA Enc=AES(128)  Mac=SHA256
ECDHE-RSA-AES128-SHA256 TLSv1.2 Kx=ECDH     Au=RSA  Enc=AES(128)  Mac=SHA256
DHE-RSA-AES128-SHA256   TLSv1.2 Kx=DH       Au=RSA  Enc=AES(128)  Mac=SHA256
ECDHE-ECDSA-AES256-SHA  TLSv1 Kx=ECDH     Au=ECDSA Enc=AES(256)  Mac=SHA1
ECDHE-RSA-AES256-SHA    TLSv1 Kx=ECDH     Au=RSA  Enc=AES(256)  Mac=SHA1
DHE-RSA-AES256-SHA      SSLv3 Kx=DH       Au=RSA  Enc=AES(256)  Mac=SHA1
ECDHE-ECDSA-AES128-SHA  TLSv1 Kx=ECDH     Au=ECDSA Enc=AES(128)  Mac=SHA1
ECDHE-RSA-AES128-SHA    TLSv1 Kx=ECDH     Au=RSA  Enc=AES(128)  Mac=SHA1
DHE-RSA-AES128-SHA      SSLv3 Kx=DH       Au=RSA  Enc=AES(128)  Mac=SHA1
RSA-PSK-AES256-GCM-SHA384 TLSv1.2 Kx=RSAPSK   Au=RSA  Enc=AESGCM(256) Mac=AEAD
DHE-PSK-AES256-GCM-SHA384 TLSv1.2 Kx=DHEPSK   Au=PSK  Enc=AESGCM(256) Mac=AEAD
RSA-PSK-CHACHA20-POLY1305 TLSv1.2 Kx=RSAPSK   Au=RSA  Enc=CHACHA20/POLY1305(256) Mac=AEAD
DHE-PSK-CHACHA20-POLY1305 TLSv1.2 Kx=DHEPSK   Au=PSK  Enc=CHACHA20/POLY1305(256) Mac=AEAD
ECDHE-PSK-CHACHA20-POLY1305 TLSv1.2 Kx=ECDHEPSK Au=PSK  Enc=CHACHA20/POLY1305(256) Mac=AEAD
AES256-GCM-SHA384       TLSv1.2 Kx=RSA      Au=RSA  Enc=AESGCM(256) Mac=AEAD
PSK-AES256-GCM-SHA384   TLSv1.2 Kx=PSK      Au=PSK  Enc=AESGCM(256) Mac=AEAD
PSK-CHACHA20-POLY1305   TLSv1.2 Kx=PSK      Au=PSK  Enc=CHACHA20/POLY1305(256) Mac=AEAD
RSA-PSK-AES128-GCM-SHA256 TLSv1.2 Kx=RSAPSK   Au=RSA  Enc=AESGCM(128) Mac=AEAD
DHE-PSK-AES128-GCM-SHA256 TLSv1.2 Kx=DHEPSK   Au=PSK  Enc=AESGCM(128) Mac=AEAD
AES128-GCM-SHA256       TLSv1.2 Kx=RSA      Au=RSA  Enc=AESGCM(128) Mac=AEAD
PSK-AES128-GCM-SHA256   TLSv1.2 Kx=PSK      Au=PSK  Enc=AESGCM(128) Mac=AEAD
AES256-SHA256           TLSv1.2 Kx=RSA      Au=RSA  Enc=AES(256)  Mac=SHA256
AES128-SHA256           TLSv1.2 Kx=RSA      Au=RSA  Enc=AES(128)  Mac=SHA256
ECDHE-PSK-AES256-CBC-SHA384 TLSv1 Kx=ECDHEPSK Au=PSK  Enc=AES(256)  Mac=SHA384
ECDHE-PSK-AES256-CBC-SHA TLSv1 Kx=ECDHEPSK Au=PSK  Enc=AES(256)  Mac=SHA1
SRP-RSA-AES-256-CBC-SHA SSLv3 Kx=SRP      Au=RSA  Enc=AES(256)  Mac=SHA1
SRP-AES-256-CBC-SHA     SSLv3 Kx=SRP      Au=SRP  Enc=AES(256)  Mac=SHA1
RSA-PSK-AES256-CBC-SHA384 TLSv1 Kx=RSAPSK   Au=RSA  Enc=AES(256)  Mac=SHA384
DHE-PSK-AES256-CBC-SHA384 TLSv1 Kx=DHEPSK   Au=PSK  Enc=AES(256)  Mac=SHA384
RSA-PSK-AES256-CBC-SHA  SSLv3 Kx=RSAPSK   Au=RSA  Enc=AES(256)  Mac=SHA1
DHE-PSK-AES256-CBC-SHA  SSLv3 Kx=DHEPSK   Au=PSK  Enc=AES(256)  Mac=SHA1
AES256-SHA              SSLv3 Kx=RSA      Au=RSA  Enc=AES(256)  Mac=SHA1
PSK-AES256-CBC-SHA384   TLSv1 Kx=PSK      Au=PSK  Enc=AES(256)  Mac=SHA384
PSK-AES256-CBC-SHA      SSLv3 Kx=PSK      Au=PSK  Enc=AES(256)  Mac=SHA1
ECDHE-PSK-AES128-CBC-SHA256 TLSv1 Kx=ECDHEPSK Au=PSK  Enc=AES(128)  Mac=SHA256
ECDHE-PSK-AES128-CBC-SHA TLSv1 Kx=ECDHEPSK Au=PSK  Enc=AES(128)  Mac=SHA1
SRP-RSA-AES-128-CBC-SHA SSLv3 Kx=SRP      Au=RSA  Enc=AES(128)  Mac=SHA1
SRP-AES-128-CBC-SHA     SSLv3 Kx=SRP      Au=SRP  Enc=AES(128)  Mac=SHA1
RSA-PSK-AES128-CBC-SHA256 TLSv1 Kx=RSAPSK   Au=RSA  Enc=AES(128)  Mac=SHA256
DHE-PSK-AES128-CBC-SHA256 TLSv1 Kx=DHEPSK   Au=PSK  Enc=AES(128)  Mac=SHA256
RSA-PSK-AES128-CBC-SHA  SSLv3 Kx=RSAPSK   Au=RSA  Enc=AES(128)  Mac=SHA1
DHE-PSK-AES128-CBC-SHA  SSLv3 Kx=DHEPSK   Au=PSK  Enc=AES(128)  Mac=SHA1
AES128-SHA              SSLv3 Kx=RSA      Au=RSA  Enc=AES(128)  Mac=SHA1
PSK-AES128-CBC-SHA256   TLSv1 Kx=PSK      Au=PSK  Enc=AES(128)  Mac=SHA256
PSK-AES128-CBC-SHA      SSLv3 Kx=PSK      Au=PSK  Enc=AES(128)  Mac=SHA1

As you can see there is plenty of matching ciphers. So why do I get this error??

----------- Bonus info---------- I have tried changing the Cipher to a single cipher, to every cipher, still same error. I have tried changing the protocol, still same error. Google has not helped me find a solution, all errors seems to be with actual missing certificates, or not related. proftpd tls config for completions sake:

#
# Proftpd sample configuration for FTPS connections.
#
# Note that FTPS impose some limitations in NAT traversing.
# See http://www.castaglia.org/proftpd/doc/contrib/ProFTPD-mini-HOWTO-TLS.html
# for more information.
#

<IfModule mod_tls.c>
TLSEngine                               on
TLSLog                                  /var/log/proftpd/tls.log
TLSProtocol                             SSLv23
#
# Server SSL certificate. You can generate a self-signed certificate using 
# a command like:
#
# openssl req -x509 -newkey rsa:1024 \
#          -keyout /etc/ssl/private/proftpd.key -out /etc/ssl/certs/proftpd.crt \
#          -nodes -days 365
#
# The proftpd.key file must be readable by root only. The other file can be
# readable by anyone.
#
# chmod 0600 /etc/ssl/private/proftpd.key 
# chmod 0640 /etc/ssl/private/proftpd.key
# 
TLSRSACertificateFile                   /etc/ssl/certs/proftpd.crt
TLSRSACertificateKeyFile                /etc/ssl/private/proftpd.key
#
# CA the server trusts...
#TLSCACertificateFile            /etc/ssl/certs/CA.pem
# ...or avoid CA cert and be verbose
TLSOptions                      NoCertRequest EnableDiags 
# ... or the same with relaxed session use for some clients (e.g. FireFtp)
#TLSOptions                      NoCertRequest EnableDiags NoSessionReuseRequired
#
#
# Per default drop connection if client tries to start a renegotiate
# This is a fix for CVE-2009-3555 but could break some clients.
#
#TLSOptions                             AllowClientRenegotiations
#
# Authenticate clients that want to use FTP over TLS?
#
#TLSVerifyClient                         off
#
# Are clients required to use FTP over TLS when talking to this server?
#
TLSRequired                             auth
#
# Allow SSL/TLS renegotiations when the client requests them, but
# do not force the renegotations.  Some clients do not support
# SSL/TLS renegotiations; when mod_tls forces a renegotiation, these
# clients will close the data connection, or there will be a timeout
# on an idle data connection.
#
#TLSRenegotiate                          required off
</IfModule>
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  • 1
    Check your server log file for more problems. No shared cipher happens also if the server cannot use the certificate you've configured and thus cannot handle any ciphers which require a certificate. – Steffen Ullrich Jun 29 at 19:20
  • ``` 2020-06-29 18:17:44,666 server proftpd[88549] server: ProFTPD 1.3.6c (maint) (built Thu Feb 27 2020 19:34:56 UTC) standalone mode STARTUP 2020-06-29 18:43:18,547 server proftpd[88549] server: ProFTPD killed (signal 15) 2020-06-29 18:43:18,551 server proftpd[88549] server: ProFTPD 1.3.6c standalone mode SHUTDOWN ``` edit: cant get code to work :\ But the log is from the same time as when I did the original post. As you can see, no errors from startup to shutdown – Ney Jun 30 at 8:12
1

It looks like your TLSProtocol is set incorrectly. It should be at worst:

TLSProtocol TLSv1 TLSv1.1 TLSv1.2

No SSLv2 or 3 should be enabled.

| improve this answer | |
  • I just used the default for the post. I have tried restricting to 1.2, that does not change the error in questions however, as it's not a protocol issue. – Ney Jun 29 at 19:11
0

Ok, so quite by accident I fell over other people having issues with openssl, and found that in newer versions the recommended keysize is set to 2048bits and not the 1024 as suggested in the proftpd guide. I tried generating new keys using 2048 bits, and now the handshake seems to work! The dataconnection however fails, but that's probably a different issue.

Edit: data connection was just the Reuse problem.

| improve this answer | |
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