I've been trying to move from using a self-signed certificate to using a wildcard certificate from a well-known CA to reduce maintenance overhead and improve security. The certificate has already been in use for months on test servers. The setup is working well enough that I can do the following (domain name anonymised):
mysql --host=host.example-dot-com-equivalent-for.co.uk --user=query_user --password --ssl
This connects successfully after providing the password. However, when I try to actually verify the certificate Common Name it fails:
$ mysql --host=host.example-dot-com-equivalent-for.co.uk --user=query_user --password --ssl --ssl-verify-server-cert
ERROR 2026 (HY000): SSL connection error: SSL certificate validation failure
After compiling MariaDB 5.5 using cmake -DCMAKE_BUILD_TYPE=Debug -DWITH_SSL=yes and running the client with --debug I get the following trace log (trimmed):
mysql_real_connect: info: Connecting
mysql_real_connect: info: net->vio: 0x0 protocol: 0
mysql_real_connect: info: Server name: 'host.example-dot-com-equivalent-for.co.uk'. TCP sock: 3306
mysql_real_connect: info: IP 'client'
mysql_real_connect: info: IPV6 getaddrinfo host.example-dot-com-equivalent-for.co.uk
mysql_real_connect: info: Try connect on all addresses for host.
mysql_real_connect: info: Create socket, family: 2 type: 1 proto: 6
mysql_real_connect: info: Connect socket
mysql_real_connect: info: End of connect attempts, sock: 4 status: 0 error: 0
mysql_real_connect: info: net->vio: 0x263c540
mysql_real_connect: info: Read first packet.
mysql_real_connect: info: mysql protocol version 10, server=10
get_charsets_dir: info: charsets dir: '/usr/local/mysql/share/charsets/'
my_stat: error: Got errno: 2 from stat
run_plugin_auth: info: using plugin mysql_native_password
native_password_auth_client: info: no password
native_password_auth_client: info: IO layer change in progress...
ssl_do: info: ssl: 0x2823e50 timeout: 0
ssl_do: info: SSL connection succeeded
ssl_do: info: Using cipher: 'AES256-GCM-SHA384'
ssl_do: info: Peer certificate:
ssl_do: info: subject: '/OU=Domain Control Validated/OU=Gandi Standard Wildcard SSL/CN=*.example-dot-com-equivalent-for.co.uk'
ssl_do: info: issuer: '/C=FR/ST=Paris/L=Paris/O=Gandi/CN=Gandi Standard SSL CA 2'
ssl_do: info: no shared ciphers!
native_password_auth_client: info: IO layer change done!
ssl_verify_server_cert: info: Server hostname in cert: *.example-dot-com-equivalent-for.co.uk
run_plugin_auth: info: authenticate_user returned CR_ERROR
run_plugin_auth: info: res=0
mysql_real_connect: error: message: 2026/HY000 (SSL connection error: SSL certificate validation failure)
end_server: info: Net:
main: info: Shutting down: infoflag: 3 print_info: 1
Note specifically that the Server name value matches the CN value.
The certificate is valid for the given hostname and is not expired, as verified by openssl s_client -connect host.example-dot-com-equivalent-for.co.uk:443 -verify_return_error < /dev/null. The "X509v3 Subject Alternative Name" field contains "DNS:*.example-dot-com-equivalent-for.co.uk, DNS:example-dot-com-equivalent-for.co.uk"
The whole certificate chain is in the file pointed to by the server's ssl-cert configuration, as recommended elsewhere. "USERTrust RSA Certification Authority" is in the client's /etc/pki/tls/certs/ca-bundle.crt and /etc/pki/tls/certs/ca-bundle.trust.crt. I tried adding --ssl-ca=/etc/pki/tls/certs/ca-bundle.crt to the command, but that didn't change anything.
The question ends up being: Do MySQL/MariaDB clients support wildcard certificates? If they do, is something wrong with my connection?
Original client:
$ mysql --version
mysql Ver 15.1 Distrib 10.1.21-MariaDB, for Linux (x86_64) using readline 5.1
Debug client:
$ ./client/mysql --version
./client/mysql Ver 15.1 Distrib 5.5.56-MariaDB, for Linux (x86_64) using readline 5.1
Server:
# rpm -q mariadb
mariadb-5.5.52-1.el7.x86_64
Posted to unix.SE rather than dba.SE because the problem may well be with the SSL libraries rather than the client.
