psql: FATAL: connection requires a valid client certificate

Question

I am trying to connect to my PostgreSQL server but psql is complaining that I don't have a valid client certificate. Here is how I create my certificates:

Self-signed server certificate:

openssl req -new -text -nodes -keyout server.key -out server.csr -subj '/C=US/ST=California/L=Fremont/O=Example/OU=CoreDev/CN=192.168.0.100' # CN is the server's IP address
openssl req -x509 -text -in server.csr -key server.key -out server.crt
cp server.crt root.crt
rm server.csr
chmod og-rwx server.key

Client certificate:

openssl req -new -nodes -keyout client.key -out client.csr -subj '/C=US/ST=California/L=Fremont/O=Example/OU=CoreDev/CN=postgres' # postgres is the database user name
openssl x509 -req -CAcreateserial -in client.csr -CA root.crt -CAkey server.key -out client.crt
rm client.csr

After copying the necessary files (client.crt, client.key, root.crt) onto the client machine and changing permission (i.e., chmod og-rwx client.key), I do the following:

psql 'host=192.168.0.100 port=5432 dbname=postgres user=postgres sslmode=verify-full sslcert=client.crt sslkey=client.key sslrootcert=root.crt'

and then I get:

psql: FATAL:  connection requires a valid client certificate

Am I doing the client certificate signing process wrong?

Thanks,

#Edit

I tried:

openssl verify -CAfile root.crt -purpose sslclient client.crt

and I get:

client.crt: OK

Using Wireshark, here is the capture I got for the communication between the client (192.168.0.103) and the server (192.168.0.100):

Do you know how to make sense of this?

#Edit 2

Okay, I did what you said, and it seems like the server does not send the CertificateRequest message to the client.. as you can see below:

but this is weird because in pg_hba.conf, I have:

hostssl all             postgres        192.168.0.103/32        cert

What do you think?

#Edit3 (SOLVED!)

I changed the pg_hba.conf to contain:

hostssl all             postgres        192.168.0.103/32        cert clientcert=1

and changed postgresql.conf to add in the "Security and Authentication" section:

ssl_ca_file = 'root.crt'

AND IT WORKED! Thank you so much!

Answer 1

In this situation I tend to pull out Wireshark and snoop the SSL negotiation to make sure the client certificate is really being offered by the client.

I suggest using openssl to verify the client->root signing link, too.

openssl verify -CAfile root.crt -purpose sslclient client.crt

Edit: It's necessary to specify clientcert=1 even when cert authentication is chosen. Yes, that's weird.