Bug#828589: uw-imap: FTBFS with openssl 1.1.0

On 2016-09-10 16:36:35 [+0200], Kurt Roeckx wrote:
> Looking at the certificate subject looks just wrong.  It should
> at least check the Subject Altnerative Name, if present, and it
> should be present.  And it really shouldn't convert it to a string
> and hope there are no other field that happen to have "CN=" in it.
> You might want to look at:
> 
> https://wiki.openssl.org/index.php/Hostname_validation

But this problem existed before 1.1.0 support (this patch).
What do you recommend here? The builtin usage
(X509_VERIFY_PARAM_set_hostflags()) looks simple. The alternative
X509_check_host() is 1.0.2+ and since it can not be applied to stable I
don't see the point. I would add this for 1.1.0 and keep the current
validation for < 1.1.0.

> Kurt

Sebastian