kdb+ v3.4t 2016.05.12 can use Secure Sockets Layer(SSL)/Transport Layer Security(TLS) to encrypt connections using the OpenSSL libraries.
Ensure that your OS has the latest OpenSSL libraries installed, and that they are in your LD_LIBRARY_PATH (unix), or PATH (windows).
kdb+ loads the following files
windows:ssleay32.dll,libeay32.dll osx:libssl.dylib linux,solaris:libssl.so
The windows build was tested with the precompiled libs (Win32 OpenSSL v1.0.2h Light, Win64 OpenSSL v1.0.2h Light) from
Since TLS uses certificates, prior to enabling TLS in a kdb+ server, ensure that you have the necessary certificates in place. The minimum for a TLS enabled server is to provide a certificate and its associated key, both in pem format. To locate these files, kdb+ will use the default path as reported by the openssl version -d command as a base, e.g.
$ openssl version -d OPENSSLDIR: "/opt/local/etc/openssl"
This default can be overridden by setting the environment variables SSL_CERT_FILE and SSL_KEY_FILE to the full path to your certificate and key files. e.g.
$export SSL_CERT_FILE=$HOME/certs/server-crt.pem $export SSL_KEY_FILE=$HOME/certs/server-key.pem
If you don't have a certificate, you can create a self-signed certificate using the openssl program. An example script to do so follows, which you should customize as necessary
$more makeCerts.sh mkdir -f $HOME/certs && cd $HOME/certs # Create CA certificate openssl genrsa 2048 > ca-key.pem openssl req -new -x509 -nodes -days 3600 -key ca-key.pem -out ca.pem -extensions usr_cert -subj '/C=US/ST=New York/L=Brooklyn/O=Example Brooklyn Company/CN=examplebrooklyn.com' # Create server certificate, remove passphrase, and sign it # server-crt.pem = public key, server-key.pem = private key openssl req -newkey rsa:2048 -days 3600 -nodes -keyout server-key.pem -out server-req.pem -extensions usr_cert -subj '/C=US/ST=New York/L=Brooklyn/O=Example Brooklyn Company/CN=myname.com' openssl rsa -in server-key.pem -out server-key.pem openssl x509 -req -in server-req.pem -days 3600 -CA ca.pem -CAkey ca-key.pem -set_serial 01 -out server-crt.pem -extensions usr_cert # Create client certificate, remove passphrase, and sign it # client-crt.pem = public key, client-key.pem = private key openssl req -newkey rsa:2048 -days 3600 -nodes -keyout client-key.pem -out client-req.pem -extensions usr_cert -subj '/C=US/ST=New York/L=Brooklyn/O=Example Brooklyn Company/CN=myname.com' openssl rsa -in client-key.pem -out client-key.pem openssl x509 -req -in client-req.pem -days 3600 -CA ca.pem -CAkey ca-key.pem -set_serial 01 -out client-crt.pem -extensions usr_cert
N.B. store your certificates outside of the directories accessible from within kdb+, otherwise remote users can easily steal your server's key file!!!
TLS Cipher List
The default cipher list is set to the 'Intermediate compatibility (default)' as recommended by Mozilla Org and the user may override this via the environment variable SSL_CIPHER_LIST, to reduce the list to whatever your IT security policy requires. A good source for what is generally recommended can be found here (Ciphersuites) https://wiki.mozilla.org/Security/Server_Side_TLS
If you select a set which is not compatible with the peer process, you'll observe a message at the q console similar to the following
140735201689680:error:1408A0C1:SSL routines:ssl3_get_client_hello:no shared cipher:s3_srvr.c:1417:
TLS Server Mode
Once the certificates are in place, and the environment variables set, TLS server mode can be enabled through the command line option -E 0 (plain), 1 (plain&tls), 2 (tls only). e.g.
$q -u 1 -E 1 -p 5000
starts a server which will listen for plain and tls connections on port 5000, restricting remote access to the pwd and below.
General TLS settings for a kdb+ process can be viewed with (-26!), e.g.
q)(-26!) SSLEAY_VERSION | OpenSSL 1.0.2g 1 Mar 2016 SSL_CERT_FILE | /Users/kdb/certs/server-crt.pem SSL_CA_CERT_FILE | /Users/kdb/certs/ca.pem SSL_CA_CERT_PATH | /Users/kdb/certs/ SSL_KEY_FILE | /Users/kdb/certs/server-key.pem SSL_CIPHER_LIST | ALL SSL_VERIFY_CLIENT| NO SSL_VERIFY_SERVER| YES
All keys except SSLEAY_VERSION in the result from (-26!) are initialized from environment variables.
By default, kdb+ does not request nor validate the certificate from a client. If the environment variable SSL_VERIFY_CLIENT is set to YES, it will try to use the certificates from SSL_CA_CERT_FILE or SSL_CA_CERT_PATH to verify the client's certificate.
Extra protocol details for a handle h are available via .z.e
q)h".z.e" CURRENT_CIPHER | AES128-GCM-SHA256 CURRENT_PROTOCOL | TLSv1.2
TLS Client Mode
TLS client mode is always enabled, and TLS Connections can be opened to TLS enabled servers with
Clients can also request secure http (https) and websockets (wss) connections via
q)(`$":https://127.0.0.1:5000")"GET /login.html http/1.1\r\nhost:www.kx.com\r\n\r\n" and for websockets q) r:(`$":wss://127.0.0.1:5000")"GET / HTTP/1.1\r\nHost: 127.0.0.1:5000\r\n\r\n"
By default kdb+ will try to verify the server's certificate against a trusted source, using the certificates from SSL_CA_CERT_FILE or SSL_CA_CERT_PATH to verify the server's certificate. If you don't wish to verify a server's certificate, set
To allow verification of certificates which were not issued by you, you can import the CA bundle from reputable sources, e.g.
$curl https://curl.haxx.se/ca/cacert.pem > $HOME/certs/cabundle.pem $export SSL_CA_CERT_FILE=$HOME/certs/cabundle.pem
If you open the downloaded cabundle.pem with a text editor you'll see a list of certificates, and you can append your own self-signed ca.pem to this file if you wish.
In the interests of not interrupting service, verification of certificates accepts expired certificates.
If there is an issue in loading the CA certificate, an error similar to the following will be printed at the q console
q).Q.hg`$":https://www.kx.com" 140735201689680:error:02001002:system library:fopen:No such file or directory:bss_file.c:175:fopen('/opt/local/etc/openssl/cacert.pem','r') 140735201689680:error:2006D080:BIO routines:BIO_new_file:no such file:bss_file.c:178: 140735201689680:error:0B084002:x509 certificate routines:X509_load_cert_crl_file:system lib:by_file.c:253: 'conn. OS reports: Protocol not available
Testing your client configuration
You can test your client configuration with
q)(`$":howsmyssl.html")0:enlist .Q.hg`$":https://www.howsmyssl.com"; And then open the resulting file with your browser, e.g. on osx use the open command q)\open howsmyssl.html
Suitability and restrictions
Currently we would recommend TLS be considered only for long-standing, latency-insensitive, low-throughput connections. The overhead of hopen on localhost appears to be 40-50x that of a plain connection, and once handshaking is complete, the overhead is ~1.5x assuming your openssl library can utilize aes-ni.
The following associated features are not yet implemented for TLS:
1) multithreaded input mode
2) hopen timeout