Warning: this will make existing curl command lines that use metalink to
stop working.
Reasons for removal:
1. We've found several security problems and issues involving the
metalink support in curl. The issues are not detailed here. When
working on those, it become apparent to the team that several of the
problems are due to the system design, metalink library API and what
the metalink RFC says. They are very hard to fix on the curl side
only.
2. The metalink usage with curl was only very briefly documented and was
not following the "normal" curl usage pattern in several ways, making
it surprising and non-intuitive which could lead to further security
issues.
3. The metalink library was last updated 6 years ago and wasn't so
active the years before that either. An unmaintained library means
there's a security problem waiting to happen. This is probably reason
enough.
4. Metalink requires an XML parsing library, which is complex code (even
the smaller alternatives) and to this day often gets security
updates.
5. Metalink is not a widely used curl feature. In the 2020 curl user
survey, only 1.4% of the responders said that they'd are using it. In
2021 that number was 1.2%. Searching the web also show very few
traces of it being used, even with other tools.
6. The torrent format and associated technology clearly won for
downloading large files from multiple sources in parallel.
Cloes #7176
include zstd curl patch for Makefile.m32 from vszakats
and include Add CMake support for zstd from Peter Wu
Helped-by: Viktor Szakats
Helped-by: Peter Wu
Closes#5453
Reported by the new script 'scripts/copyright.pl'. The script has a
regex whitelist for the files that don't need copyright headers.
Removed three (mostly usesless) README files from docs/
Closes#5141
also:
- fix two warnings in synctime.c (one of them Windows-specific)
- upgrade URLs in synctime.c and remove a broken one
Closes https://github.com/curl/curl/pull/3033
- update default versions of dependencies (except for rare/old platforms)
- update urls
- sync examples makefiles with main ones
- remove line ending space
This is just fundamentally broken. SPNEGO (RFC4178) is a protocol which
allows client and server to negotiate the underlying mechanism which will
actually be used to authenticate. This is *often* Kerberos, and can also
be NTLM and other things. And to complicate matters, there are various
different OIDs which can be used to specify the Kerberos mechanism too.
A SPNEGO exchange will identify *which* GSSAPI mechanism is being used,
and will exchange GSSAPI tokens which are appropriate for that mechanism.
But this SPNEGO implementation just strips the incoming SPNEGO packet
and extracts the token, if any. And completely discards the information
about *which* mechanism is being used. Then we *assume* it was Kerberos,
and feed the token into gss_init_sec_context() with the default
mechanism (GSS_S_NO_OID for the mech_type argument).
Furthermore... broken as this code is, it was never even *used* for input
tokens anyway, because higher layers of curl would just bail out if the
server actually said anything *back* to us in the negotiation. We assume
that we send a single token to the server, and it accepts it. If the server
wants to continue the exchange (as is required for NTLM and for SPNEGO
to do anything useful), then curl was broken anyway.
So the only bit which actually did anything was the bit in
Curl_output_negotiate(), which always generates an *initial* SPNEGO
token saying "Hey, I support only the Kerberos mechanism and this is its
token".
You could have done that by manually just prefixing the Kerberos token
with the appropriate bytes, if you weren't going to do any proper SPNEGO
handling. There's no need for the FBOpenSSL library at all.
The sane way to do SPNEGO is just to *ask* the GSSAPI library to do
SPNEGO. That's what the 'mech_type' argument to gss_init_sec_context()
is for. And then it should all Just Work™.
That 'sane way' will be added in a subsequent patch, as will bug fixes
for our failure to handle any exchange other than a single outbound
token to the server which results in immediate success.
