Re: [Bug-wget] wget sets gnutls priority multiple times

[Tim Ruehsen]

On Monday, December 19, 2016 4:09:08 PM CET Nikos Mavrogiannopoulos wrote:
> Hi,
>  While debugging some issue in Fedora [0] I've realized that wget calls
> the gnutls priority functions multiple times, and that confuses gnutls
> on certain cases. In src/gnutls.c wget calls
> gnutls_set_default_priority (session) which sets the default cipher
> priorities according to the system policy. However, at the following
> lines it overwrites that policy in the switch (opt.secure_protocol).
> 
> In particular, when no options are given it enters:
> ```
>     case secure_protocol_auto:
>       err = gnutls_priority_set_direct (session,
> "NORMAL:%COMPAT:-VERS-SSL3.0", NULL); ```
> 
> That means that the default policy set above is overwritten. A possible
> fix is attached. That ensures that the priorities are set only once and
> that the default priorities are used when no options are specified (the
> latter is important for Fedora which ensures that
> gnutls_set_default_priority() sets a priority string according to the
> system-wide policies.
> 
> The use of keyword %COMPAT is replaced by calling
> gnutls_session_enable_compatibility_mode().

Thanks, Nikos.

I like the idea of having a system wide TLS/security policy.

But what happens when wget is build with an older version of GnuTLS that 
doesn't disable SSL3.0 by default ? Before your change, these people where 
'save' from using SSL, with your change applied we introduce insecurity by 
default.

Since what version did you disable SSL by default ? We could make a run-time 
version check to explicitly disable SSL then.

Regards, Tim

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