fix #833

[bricewge]

It partially revert the changes made in 9c6a5f3. But I used ASN1_STRING_get0_data() instead of the previous ASN1_STRING_data() because openssl say it is deprecated.

[bricewge]

Updated due to the remarks of @ptjm at #833 (comment). It should work with openssl before version 1.1 and not broke when the CN contains nulls (https://wiki.openssl.org/index.php/Hostname_validation).

[toast-uz]

Note there is a comment as bellow in ChangeLog.txt on mosquitto v1.5.

- Support for openssl versions 1.0.0 and 1.0.1 has been removed as these are
  no longer supported by openssl.

What do you think about that?

[bricewge]

I wasn't aware of this comment.
@toast-uz Do you want me to update the PR to use ASN1_STRING_get0_data() instead so it only support openssl 1.1 and higher?

[toast-uz]

Openssl 1.0.2 is still available. Is your patch needed and available with openssl 1.0.2?

[bricewge]

Yes it's needed since it fix a mosquitto bug and it should work with openssl 1.0.2.

[toast-uz]

OK. Understood this PR is valid. Then keep this PR and related issue.

[ralight]

Thanks for this PR, could you please sign the Eclipse Contributor Agreement and add a signed-off-by line to your commit message?

https://www.eclipse.org/legal/ECA.php

To add the line, do:

git commit --amend -s
git push -f

That should just update this PR.

[bricewge]

I just signed the ECA.

I didn't bothered to sign it at first because the first patch was trivial.

[ralight]

Lovely, thanks. I'll get to this later this afternoon.

[ralight]

I've merged this manually so it could go on the fixes branch rather than master, so I'm going to close this as merged. The commit is at the link below, thanks very much for your contribution.

2a3305a