Attempt to add support for Secure Channel binding when negotiate
authentication is used. The problem to solve is that by default IIS
accepts channel binding and curl doesn't utilise them. The result was a
401 response. Scope affects only the Schannel(winssl)-SSPI combination.
Fixes https://github.com/curl/curl/issues/3503
Closes https://github.com/curl/curl/pull/3509
We use "conn" everywhere to be a pointer to the connection.
Introduces two functions that "attaches" and "detaches" the connection
to and from the transfer.
Going forward, we should favour using "data->conn" (since a transfer
always only has a single connection or none at all) to "conn->data"
(since a connection can have none, one or many transfers associated with
it and updating conn->data to be correct is error prone and a frequent
reason for internal issues).
Closes#3442
When a zeroed out allocation is required, use calloc() rather than
malloc() followed by an explicit memset(). The result will be the
same, but using calloc() everywhere increases consistency in the
codebase and avoids the risk of subtle bugs when code is injected
between malloc and memset by accident.
Closes https://github.com/curl/curl/pull/2497
As Windows SSPI authentication calls fail when a particular mechanism
isn't available, introduced these functions for DIGEST, NTLM, Kerberos 5
and Negotiate to allow both HTTP and SASL authentication the opportunity
to query support for a supported mechanism before selecting it.
For now each function returns TRUE to maintain compatability with the
existing code when called.
