error:failed to load the certificate about mqtt-c

[rosepinkr]

x509 certificate verification failed msg
But when i use the same certificate on mosquitto pub it works.
Do you have any solution for this?

[LiamBindle]

Hi,

I'm actually not too familiar with TLS/SSL so I might not be the best person to help debug this, but I can try. I'm also moving right now, so I apologize if my responses are slow (also I don't have access to my computer right now so I can't try to reproduce).

In templates/openssl_sockets.h I have written a barebones function—called open_nb_socket—that opens a secure connection and returns the associated BIO socket (this function is called in the openssl_publisher example). To get MQTT-C working on an encrypted connection you must create this BIO socket (i.e. open and verify the connection) and that's it.

I think that you will have to do some debugging in this function. If you are getting an error saying that the certificate failed to load then SSL_CTX_load_verify_locations on line 16 of tempaltes/openssl_sockets.h must be returning false. I'd start with figuring out why this is.

You could also check that there aren't any SSL errors immediately after loading OpenSSL (i.e. check the state of OpenSSL error at line 50 of openssl_publisher.c.

Here are some resources for error handling in OpenSSL:

• https://en.wikibooks.org/wiki/OpenSSL/Error_handling
• https://www.openssl.org/docs/man1.1.0/crypto/ERR_print_errors_fp.html
• https://stackoverflow.com/questions/37980798/openssl-error-handling
• https://www.ibm.com/developerworks/library/l-openssl/index.html

Let me know how it goes and if there is anything I can help you with.

Best regards,

Liam

[LiamBindle]

Because of inactivity, I'm going to assume this issue can be closed.

Please feel free to reopen if you continue to have trouble.