rand: only provide weak random when needed

builds without TLS and builds using rustls

Closes #14749

tidy-up: spelling quiche and Rustls

Closes #14605

spnego_gssapi: implement TLS channel bindings for openssl

Channel Bindings are used to tie the session context to a specific TLS
channel. This is to provide additional proof of valid ide

spnego_gssapi: implement TLS channel bindings for openssl

Channel Bindings are used to tie the session context to a specific TLS
channel. This is to provide additional proof of valid identity,
mitigating authentication relay attacks.

Major web servers have the ability to require (None/Accept/Require)
GSSAPI channel binding, rendering Curl unable to connect to such
websites unless support for channel bindings is implemented.

IIS calls this feature Extended Protection (EPA), which is used in
Enterprise environments using Kerberos for authentication.

This change require krb5 >= 1.19, otherwise channel bindings won't be
forwarded through SPNEGO.

Co-Authored-By: Steffen Kieß <947515+steffen-kiess@users.noreply.github.com>
Closes #13098

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vtls: replace addsessionid with set_sessionid

- deduplicate the code in many tls backends that check
for an existing id and delete it before adding the new one
- rename ssl_primary

vtls: replace addsessionid with set_sessionid

- deduplicate the code in many tls backends that check
for an existing id and delete it before adding the new one
- rename ssl_primary_config's `sessionid` bool to `cache_session`

Closes #14121

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lib: graceful connection shutdown

When libcurl discards a connection there are two phases this may go
through: "shutdown" and "closing". If a connection is aborted, the
shutdown phas

lib: graceful connection shutdown

When libcurl discards a connection there are two phases this may go
through: "shutdown" and "closing". If a connection is aborted, the
shutdown phase is skipped and it is closed right away.

The connection filters attached to the connection implement the phases
in their `do_shutdown()` and `do_close()` callbacks. Filters carry now a
`shutdown` flags next to `connected` to keep track of the shutdown
operation.

Filters are shut down from top to bottom. If a filter is not connected,
its shutdown is skipped. Notable filters that *do* something during
shutdown are HTTP/2 and TLS. HTTP/2 sends the GOAWAY frame. TLS sends
its close notify and expects to receive a close notify from the server.

As sends and receives may EAGAIN on the network, a shutdown is often not
successful right away and needs to poll the connection's socket(s). To
facilitate this, such connections are placed on a new shutdown list
inside the connection cache.

Since managing this list requires the cooperation of a multi handle,
only the connection cache belonging to a multi handle is used. If a
connection was in another cache when being discarded, it is removed
there and added to the multi's cache. If no multi handle is available at
that time, the connection is shutdown and closed in a one-time,
best-effort attempt.

When a multi handle is destroyed, all connection still on the shutdown
list are discarded with a final shutdown attempt and close. In curl
debug builds, the environment variable `CURL_GRACEFUL_SHUTDOWN` can be
set to make this graceful with a timeout in milliseconds given by the
variable.

The shutdown list is limited to the max number of connections configured
for a multi cache. Set via CURLMOPT_MAX_TOTAL_CONNECTIONS. When the
limit is reached, the oldest connection on the shutdown list is
discarded.

- In multi_wait() and multi_waitfds(), collect all connection caches
involved (each transfer might carry its own) into a temporary list.
Let each connection cache on the list contribute sockets and
POLLIN/OUT events it's connections are waiting for.

- in multi_perform() collect the connection caches the same way and let
them peform their maintenance. This will make another non-blocking
attempt to shutdown all connections on its shutdown list.

- for event based multis (multi->socket_cb set), add the sockets and
their poll events via the callback. When `multi_socket()` is invoked
for a socket not known by an active transfer, forward this to the
multi's cache for processing. On closing a connection, remove its
socket(s) via the callback.

TLS connection filters MUST NOT send close nofity messages in their
`do_close()` implementation. The reason is that a TLS close notify
signals a success. When a connection is aborted and skips its shutdown
phase, the server needs to see a missing close notify to detect
something has gone wrong.

A graceful shutdown of FTP's data connection is performed implicitly
before regarding the upload/download as complete and continuing on the
control connection. For FTP without TLS, there is just the socket close
happening. But with TLS, the sent/received close notify signals that the
transfer is complete and healthy. Servers like `vsftpd` verify that and
reject uploads without a TLS close notify.

- added test_19_* for shutdown related tests
- test_19_01 and test_19_02 test for TCP RST packets
which happen without a graceful shutdown and should
no longer appear otherwise.
- add test_19_03 for handling shutdowns by the server
- add test_19_04 for handling shutdowns by curl
- add test_19_05 for event based shutdowny by server
- add test_30_06/07 and test_31_06/07 for shutdown checks
on FTP up- and downloads.

Closes #13976

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connection: shutdown TLS (for FTP) better

This adds connection shutdown infrastructure and first use for FTP. FTP
data connections, when not encountering an error, are now shut down in a

connection: shutdown TLS (for FTP) better

This adds connection shutdown infrastructure and first use for FTP. FTP
data connections, when not encountering an error, are now shut down in a
blocking way with a 2sec timeout.

- add cfilter `Curl_cft_shutdown` callback
- keep a shutdown start timestamp and timeout at connectdata
- provide shutdown timeout default and member in
`data->set.shutdowntimeout`.
- provide methods for starting, interrogating and clearing
shutdown timers
- provide `Curl_conn_shutdown_blocking()` to shutdown the
`sockindex` filter chain in a blocking way. Use that in FTP.
- add `Curl_conn_cf_poll()` to wait for socket events during
shutdown of a connection filter chain.
This gets the monitoring sockets and events via the filters
"adjust_pollset()" methods. This gives correct behaviour when
shutting down a TLS connection through a HTTP/2 proxy.
- Implement shutdown for all socket filters
- for HTTP/2 and h2 proxying to send GOAWAY
- for TLS backends to the best of their capabilities
- for tcp socket filter to make a final, nonblocking
receive to avoid unwanted RST states
- add shutdown forwarding to happy eyeballers and
https connect ballers when applicable.

Closes #13904

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vtls: new io_need flags for poll handling

- decouple need to recv/send from negotiation state, we need
this later in shutdown handling as well
- move ssl enums from urldata.h to vt

vtls: new io_need flags for poll handling

- decouple need to recv/send from negotiation state, we need
this later in shutdown handling as well
- move ssl enums from urldata.h to vtls_int.h
- implement use of `connssl->io_need` in vtls.c. and all backends

Closes #13879

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multi: add multi->proto_hash, a key-value store for protocol data

- add `Curl_hash_add2()` that passes a destructor function for
the element added. Call element destructor instead of h

multi: add multi->proto_hash, a key-value store for protocol data

- add `Curl_hash_add2()` that passes a destructor function for
the element added. Call element destructor instead of hash
destructor if present.
- multi: add `proto_hash` for protocol related information,
remove `struct multi_ssl_backend_data`.
- openssl: use multi->proto_hash to keep x509 shared store
- schannel: use multi->proto_hash to keep x509 shared store
- vtls: remove Curl_free_multi_ssl_backend_data() and its
equivalents in the TLS backends

Closes #13345

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vtls: TLS session storage overhaul

- add session with destructor callback
- remove vtls `session_free` method
- let `Curl_ssl_addsessionid()` take ownership
of session object,

vtls: TLS session storage overhaul

- add session with destructor callback
- remove vtls `session_free` method
- let `Curl_ssl_addsessionid()` take ownership
of session object, freeing it also on failures
- change tls backend use
- test_17, add tests for SSL session resumption

Closes #13386

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tls: use shared init code for TCP+QUIC

Closes #13172

TLS: start shutdown only when peer did not already close

- When curl sees a TCP close from the peer, do not start a TLS shutdown.
TLS shutdown is a handshake and if the peer already cl

TLS: start shutdown only when peer did not already close

- When curl sees a TCP close from the peer, do not start a TLS shutdown.
TLS shutdown is a handshake and if the peer already closed the
connection, it is not interested in participating.

Reported-by: dfdity on github
Assisted-by: Jiří Bok
Assisted-by: Pēteris Caune
Fixes #10290
Closes #13087

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openssl: when a session-ID is reused, skip OCSP stapling

Fixes #12399
Reported-by: Alexey Larikov
Closes #12418

vtls/vquic, keep peer name information together

- add `struct ssl_peer` to keep hostname, dispname and sni
for a filter
- allocate `sni` for use in VTLS backend
- eliminate `Cu

vtls/vquic, keep peer name information together

- add `struct ssl_peer` to keep hostname, dispname and sni
for a filter
- allocate `sni` for use in VTLS backend
- eliminate `Curl_ssl_snihost()` and its use of the download buffer
- use ssl_peer in SSL and QUIC filters

Closes #12349

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vtls: use ALPN "http/1.1" for HTTP/1.x, including HTTP/1.0

Some servers don't support the ALPN protocol "http/1.0" (e.g. IIS 10),
avoid it and use "http/1.1" instead.

This rever

vtls: use ALPN "http/1.1" for HTTP/1.x, including HTTP/1.0

Some servers don't support the ALPN protocol "http/1.0" (e.g. IIS 10),
avoid it and use "http/1.1" instead.

This reverts commit df856cb5c9 (#10183).

Fixes #12259
Closes #12285

show more ...

vtls: cleanup SSL config management

- remove `Curl_ssl_get_config()`, no longer needed

Closes #12204

lib: introduce struct easy_poll_set for poll information

Connection filter had a `get_select_socks()` method, inspired by the
various `getsocks` functions involved during the lifetime of

lib: introduce struct easy_poll_set for poll information

Connection filter had a `get_select_socks()` method, inspired by the
various `getsocks` functions involved during the lifetime of a
transfer. These, depending on transfer state (CONNECT/DO/DONE/ etc.),
return sockets to monitor and flag if this shall be done for POLLIN
and/or POLLOUT.

Due to this design, sockets and flags could only be added, not
removed. This led to problems in filters like HTTP/2 where flow control
prohibits the sending of data until the peer increases the flow
window. The general transfer loop wants to write, adds POLLOUT, the
socket is writeable but no data can be written.

This leads to cpu busy loops. To prevent that, HTTP/2 did set the
`SEND_HOLD` flag of such a blocked transfer, so the transfer loop cedes
further attempts. This works if only one such filter is involved. If a
HTTP/2 transfer goes through a HTTP/2 proxy, two filters are
setting/clearing this flag and may step on each other's toes.

Connection filters `get_select_socks()` is replaced by
`adjust_pollset()`. They get passed a `struct easy_pollset` that keeps
up to `MAX_SOCKSPEREASYHANDLE` sockets and their `POLLIN|POLLOUT`
flags. This struct is initialized in `multi_getsock()` by calling the
various `getsocks()` implementations based on transfer state, as before.

After protocol handlers/transfer loop have set the sockets and flags
they want, the `easy_pollset` is *always* passed to the filters. Filters
"higher" in the chain are called first, starting at the first
not-yet-connection one. Each filter may add sockets and/or change
flags. When all flags are removed, the socket itself is removed from the
pollset.

Example:

* transfer wants to send, adds POLLOUT
* http/2 filter has a flow control block, removes POLLOUT and adds
POLLIN (it is waiting on a WINDOW_UPDATE from the server)
* TLS filter is connected and changes nothing
* h2-proxy filter also has a flow control block on its tunnel stream,
removes POLLOUT and adds POLLIN also.
* socket filter is connected and changes nothing
* The resulting pollset is then mixed together with all other transfers
and their pollsets, just as before.

Use of `SEND_HOLD` is no longer necessary in the filters.

All filters are adapted for the changed method. The handling in
`multi.c` has been adjusted, but its state handling the the protocol
handlers' `getsocks` method are untouched.

The most affected filters are http/2, ngtcp2, quiche and h2-proxy. TLS
filters needed to be adjusted for the connecting handshake read/write
handling.

No noticeable difference in performance was detected in local scorecard
runs.

Closes #11833

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gskit: remove

We remove support for building curl with gskit.

- This is a niche TLS library, only running on some IBM systems
- no regular curl contributors use this backend

gskit: remove

We remove support for building curl with gskit.

- This is a niche TLS library, only running on some IBM systems
- no regular curl contributors use this backend
- no CI builds use or verify this backend
- gskit, or the curl adaption for it, lacks many modern TLS features
making it an inferior solution
- build breakages in this code take weeks or more to get detected
- fixing gskit code is mostly done "flying blind"

This removal has been advertized in DEPRECATED in Jan 2, 2023 and it has
been mentioned on the curl-library mailing list.

It could be brought back, this is not a ban. Given proper effort and
will, gskit support is welcome back into the curl TLS backend family.

Closes #11460

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nss: remove support for this TLS library

Closes #11459

cmake: add support for "unity" builds

Aka "jumbo" or "amalgamation" builds. It means to compile all sources
per target as a single C source. This is experimental.

You can enable

cmake: add support for "unity" builds

Aka "jumbo" or "amalgamation" builds. It means to compile all sources
per target as a single C source. This is experimental.

You can enable it by passing `-DCMAKE_UNITY_BUILD=ON` to cmake.
It requires CMake 3.16 or newer.

It makes builds (much) faster, allows for better optimizations and tends
to promote less ambiguous code.

Also add a new AppVeyor CI job and convert an existing one to use
"unity" mode (one MSVC, one MinGW), and enable it for one macOS CI job.

Fix related issues:
- add missing include guard to `easy_lock.h`.
- rename static variables and functions (and a macro) with names reused
across sources, or shadowed by local variables.
- add an `#undef` after use.
- add a missing `#undef` before use.
- move internal definitions from `ftp.h` to `ftp.c`.
- `curl_memory.h` fixes to make it work when included repeatedly.
- stop building/linking curlx bits twice for a static-mode curl tool.
These caused doubly defined symbols in unity builds.
- silence missing extern declarations compiler warning for ` _CRT_glob`.
- fix extern declarations for `tool_freq` and `tool_isVistaOrGreater`.
- fix colliding static symbols in debug mode: `debugtime()` and
`statename`.
- rename `ssl_backend_data` structure to unique names for each
TLS-backend, along with the `ssl_connect_data` struct member
referencing them. This required adding casts for each access.
- add workaround for missing `[P]UNICODE_STRING` types in certain Windows
builds when compiling `lib/ldap.c`. To support "unity" builds, we had
to enable `SCHANNEL_USE_BLACKLISTS` for Schannel (a Windows
`schannel.h` option) _globally_. This caused an indirect inclusion of
Windows `schannel.h` from `ldap.c` via `winldap.h` to have it enabled
as well. This requires `[P]UNICODE_STRING` types, which is apperantly
not defined automatically (as seen with both MSVS and mingw-w64).
This patch includes `<subauth.h>` to fix it.
Ref: https://github.com/curl/curl/runs/13987772013
Ref: https://dev.azure.com/daniel0244/curl/_build/results?buildId=15827&view=logs&jobId=2c9f582d-e278-56b6-4354-f38a4d851906&j=2c9f582d-e278-56b6-4354-f38a4d851906&t=90509b00-34fa-5a81-35d7-5ed9569d331c
- tweak unity builds to compile `lib/memdebug.c` separately in memory
trace builds to avoid PP confusion.
- force-disable unity for test programs.
- do not compile and link libcurl sources to libtests _twice_ when libcurl
is built in static mode.

KNOWN ISSUES:
- running tests with unity builds may fail in cases.
- some build configurations/env may not compile in unity mode. E.g.:
https://ci.appveyor.com/project/curlorg/curl/builds/47230972/job/51wfesgnfuauwl8q#L250

Ref: https://github.com/libssh2/libssh2/issues/1034
Ref: https://cmake.org/cmake/help/latest/prop_tgt/UNITY_BUILD.html
Ref: https://en.wikipedia.org/wiki/Unity_build

Closes #11095

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proxy: http2 proxy tunnel implementation

- currently only on debug build and when env variable
CURL_PROXY_TUNNEL_H2 is present.
- will ALPN negotiate with the proxy server and swit

proxy: http2 proxy tunnel implementation

- currently only on debug build and when env variable
CURL_PROXY_TUNNEL_H2 is present.
- will ALPN negotiate with the proxy server and switch
tunnel filter based on the protocol negotiated.
- http/1.1 tunnel code moved into cf-h1-proxy.[ch]
- http/2 tunnel code implemented in cf-h2-proxy.[ch]
- tunnel start and ALPN set remains in http_proxy.c
- moving all haproxy related code into cf-haproxy.[ch]

VTLS changes
- SSL filters rely solely on the "alpn" specification they
are created with and no longer check conn->bits.tls_enable_alpn.
- checks on which ALPN specification to use (or none at all) are
done in vtls.c when creating the filter.

Testing
- added a nghttpx forward proxy to the pytest setup that
speaks HTTP/2 and forwards all requests to the Apache httpd
forward proxy server.
- extending test coverage in test_10 cases
- adding proxy tests for direct/tunnel h1/h2 use of basic auth.
- adding test for http/1.1 and h2 proxy tunneling to pytest

Closes #10780

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connections: introduce http/3 happy eyeballs

New cfilter HTTP-CONNECT for h3/h2/http1.1 eyeballing.
- filter is installed when `--http3` in the tool is used (or
the equivalent CURL

connections: introduce http/3 happy eyeballs

New cfilter HTTP-CONNECT for h3/h2/http1.1 eyeballing.
- filter is installed when `--http3` in the tool is used (or
the equivalent CURLOPT_ done in the library)
- starts a QUIC/HTTP/3 connect right away. Should that not
succeed after 100ms (subject to change), a parallel attempt
is started for HTTP/2 and HTTP/1.1 via TCP
- both attempts are subject to IPv6/IPv4 eyeballing, same
as happens for other connections
- tie timeout to the ip-version HAPPY_EYEBALLS_TIMEOUT
- use a `soft` timeout at half the value. When the soft timeout
expires, the HTTPS-CONNECT filter checks if the QUIC filter
has received any data from the server. If not, it will start
the HTTP/2 attempt.

HTTP/3(ngtcp2) improvements.
- setting call_data in all cfilter calls similar to http/2 and vtls filters
for use in callback where no stream data is available.
- returning CURLE_PARTIAL_FILE for prematurely terminated transfers
- enabling pytest test_05 for h3
- shifting functionality to "connect" UDP sockets from ngtcp2
implementation into the udp socket cfilter. Because unconnected
UDP sockets are weird. For example they error when adding to a
pollset.

HTTP/3(quiche) improvements.
- fixed upload bug in quiche implementation, now passes 251 and pytest
- error codes on stream RESET
- improved debug logs
- handling of DRAIN during connect
- limiting pending event queue

HTTP/2 cfilter improvements.
- use LOG_CF macros for dynamic logging in debug build
- fix CURLcode on RST streams to be CURLE_PARTIAL_FILE
- enable pytest test_05 for h2
- fix upload pytests and improve parallel transfer performance.

GOAWAY handling for ngtcp2/quiche
- during connect, when the remote server refuses to accept new connections
and closes immediately (so the local conn goes into DRAIN phase), the
connection is torn down and a another attempt is made after a short grace
period.
This is the behaviour observed with nghttpx when we tell it to shut
down gracefully. Tested in pytest test_03_02.

TLS improvements
- ALPN selection for SSL/SSL-PROXY filters in one vtls set of functions, replaces
copy of logic in all tls backends.
- standardized the infof logging of offered ALPNs
- ALPN negotiated: have common function for all backends that sets alpn proprty
and connection related things based on the negotiated protocol (or lack thereof).

- new tests/tests-httpd/scorecard.py for testing h3/h2 protocol implementation.
Invoke:
python3 tests/tests-httpd/scorecard.py --help
for usage.

Improvements on gathering connect statistics and socket access.
- new CF_CTRL_CONN_REPORT_STATS cfilter control for having cfilters
report connection statistics. This is triggered when the connection
has completely connected.
- new void Curl_pgrsTimeWas(..) method to report a timer update with
a timestamp of when it happend. This allows for updating timers
"later", e.g. a connect statistic after full connectivity has been
reached.
- in case of HTTP eyeballing, the previous changes will update
statistics only from the filter chain that "won" the eyeballing.
- new cfilter query CF_QUERY_SOCKET for retrieving the socket used
by a filter chain.
Added methods Curl_conn_cf_get_socket() and Curl_conn_get_socket()
for convenient use of this query.
- Change VTLS backend to query their sub-filters for the socket when
checks during the handshake are made.

HTTP/3 documentation on how https eyeballing works.

TLS improvements
- ALPN selection for SSL/SSL-PROXY filters in one vtls set of functions, replaces
copy of logic in all tls backends.
- standardized the infof logging of offered ALPNs
- ALPN negotiated: have common function for all backends that sets alpn proprty
and connection related things based on the negotiated protocol (or lack thereof).

Scorecard with Caddy.
- configure can be run with `--with-test-caddy=path` to specify which caddy to use for testing
- tests/tests-httpd/scorecard.py now measures download speeds with caddy

pytest improvements
- adding Makfile to clean gen dir
- adding nghttpx rundir creation on start
- checking httpd version 2.4.55 for test_05 cases where it is needed. Skipping with message if too old.
- catch exception when checking for caddy existance on system.

Closes #10349

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vtls: Manage current easy handle in nested cfilter calls

The previous implementation cleared `data` so the outer invocation lost
its data, which could lead to a crash.

Bug: http

vtls: Manage current easy handle in nested cfilter calls

The previous implementation cleared `data` so the outer invocation lost
its data, which could lead to a crash.

Bug: https://github.com/curl/curl/issues/10336
Reported-by: Fujii Hironori

Closes https://github.com/curl/curl/pull/10340

show more ...

vtls: fix hostname handling in filters

- Copy the hostname and dispname to ssl_connect_data.

Use a copy instead of referencing the `connectdata` instance since this
may get free

vtls: fix hostname handling in filters

- Copy the hostname and dispname to ssl_connect_data.

Use a copy instead of referencing the `connectdata` instance since this
may get free'ed on connection reuse.

Reported-by: Stefan Talpalaru
Reported-by: sergio-nsk@users.noreply.github.com

Fixes https://github.com/curl/curl/issues/10273
Fixes https://github.com/curl/curl/issues/10309

Closes https://github.com/curl/curl/pull/10310

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copyright: update all copyright lines and remove year ranges

- they are mostly pointless in all major jurisdictions
- many big corporations and projects already don't use them
- save

copyright: update all copyright lines and remove year ranges

- they are mostly pointless in all major jurisdictions
- many big corporations and projects already don't use them
- saves us from pointless churn
- git keeps history for us
- the year range is kept in COPYING

checksrc is updated to allow non-year using copyright statements

Closes #10205

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vtls: fix typo in vtls_int.h

paramter -> parameter

Closes: #9996
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>