Mosquitto SSL certificate verify failed - ssl

Question

I'm using Mosquitto version 1.4.8 on my test PC and the server. The server is accessible via ha.euroicc.com.
I've generated certificates and keys using the following script:
#! /usr/bin/env bash
# Create the CA Key and Certificate for signing Client Certs
openssl genrsa -out ca.key 4096
openssl req -new -x509 -days 365 -key ca.key -out ca.crt
# Create the Server Key, CSR, and Certificate
openssl genrsa -out server.key 1024
openssl req -new -key server.key -out server.csr
# We're self signing our own server cert here. This is a no-no in production.
openssl x509 -req -days 365 -in server.csr -CA ca.crt -CAkey ca.key -set_serial 01 -out server.crt
# Create the Client Key and CSR
openssl genrsa -out client.key 1024
openssl req -new -key client.key -out client.csr
# Sign the client certificate with our CA cert. Unlike signing our own server cert, this is what we want to do.
# Serial should be different from the server one, otherwise curl will return NSS error -8054
openssl x509 -req -days 365 -in client.csr -CA ca.crt -CAkey ca.key -set_serial 02 -out client.crt
# Verify Server Certificate
openssl verify -purpose sslserver -CAfile ca.crt server.crt
# Verify Client Certificate
openssl verify -purpose sslclient -CAfile ca.crt client.crt
I've put 'd', 'dd' and 'dddd' everywhere except for common name.
The common name for ca is 'd' and for server/client is 'ha.euroicc.com'.
CN for server/client needs to be this value, or it doesn't work at all!
My current mosquitto config file:
pid_file /var/run/mosquitto.pid
persistence true
persistence_location /var/lib/mosquitto/
persistence_file mosquitto.db
log_dest syslog
log_dest stdout
log_dest topic
log_type error
log_type warning
log_type notice
log_type information
connection_messages true
log_timestamp true
password_file /etc/mosquitto/passwd
log_dest file /var/log/mosquitto/mosquitto.log
include_dir /etc/mosquitto/conf.d
allow_anonymous false
port 8883
cafile /etc/mosquitto/certs/ca.crt
keyfile /etc/mosquitto/certs/server.key
certfile /etc/mosquitto/certs/server.crt
require_certificate true
I use this command to subscribe from test PC:
mosquitto_sub -h ha.euroicc.com -t "topic/test" -u "damjan" -P "damjan" -p 8883 --cafile ca.crt --key client.key --cert client.crt
And get these errors:
On test PC:
Error: A TLS error occurred.
On server:
1532564086: OpenSSL Error: error:14089086:SSL
routines:ssl3_get_client_certificate:certificate verify failed
1532564086: Socket error on client <unknown>, disconnecting.
I've tried without require_certificate set on the server side, and not using client key/cert on the client side and subscription works in this case. This means that username/password parameters are fine.
That means that I either generated certificates and keys with a problem, my mosquitto.conf is bad or I'm using mosquitto_sub with a problem. Maybe something else?
I'm really at loss here and can't figure out what to try next...
Every bit of information helps.

Answer 1

Had a similar issue while upgrading to 2.0 because of the updated TLS/SSL bindings several know weak algorithms are not supported anymore.
In my case the signature of the certificate was sha1WithRSAEncryption where sha1 is the weak part. The same would be for e.g. MD5.
Check your certificate with openssl x509 -text -noout -in your.crt
Resigning the certificate with sha256WithRSAEncryption fixed it for me.
There is no need to create a new key.
You can either create a new CSR from your existing key and information from your certificate:
openssl x509 -x509toreq -in sha1.crt -signkey sha1.key -out sha256-new.csr -sha256
or overwrite the algorithm while signing the existing CSR again:
openssl x509 -req -days 360 -in sha1.csr -CA DummyCA-DonotTrust.pem -CAkey DummyCA-DonotTrust.pem -CAcreateserial -out sha256.crt -sha256
Recent openssl version should use sha256 as default.
Debian has changed the default setting with openssl-1.1.1 see https://wiki.debian.org/ContinuousIntegration/TriagingTips/openssl-1.1.1 and set CipherString = DEFAULT#SECLEVEL=2.
To get a list of supported algorithms run: openssl ciphers -s -v 'ALL:#SECLEVEL=2'

Answer 2

Ok, so the problem was that I was generating all of the files on my test PC, and then sending it to the server.
I've tried generating everything on the server, and then copying appropriate files to my test PC, and everything works fine.
I've followed http://rockingdlabs.dunmire.org/exercises-experiments/ssl-client-certs-to-secure-mqtt . With lesser changes like hostname etc.

Answer 3

I had the same issue.
To fix it, while generating server.crt, answer to question 'Common Name' with IP address of the machine where Mqtt broker is going to be run.