gtls: Add P12 format support

This change adds P12 format support for GnuTLS backend.

Closes #14991

lib/src: white space edits to comply better with code style

... as checksrc now finds and complains about these.

Closes #14921

gnutls: send all data

Turns out `gnutls_record_send()` does really what the name says: it
sends exactly one TLS record. If more than 16k are there to send, it
needs to be called agai

gnutls: send all data

Turns out `gnutls_record_send()` does really what the name says: it
sends exactly one TLS record. If more than 16k are there to send, it
needs to be called again with new buffer offset and length.

Continue sending record until the input is all sent or a EAGAIN (or
fatal error) is returned by gnutls.

Closes #14722

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gtls: fix OCSP stapling management

Reported-by: Hiroki Kurosawa
Closes #14642

gnutls/wolfssl: improve error message when certificate fails

Give more detailed reasons for certificate failures where available in
gnutls and wolfssi to allow user to understand the cau

gnutls/wolfssl: improve error message when certificate fails

Give more detailed reasons for certificate failures where available in
gnutls and wolfssi to allow user to understand the cause of the failure.

Closes #14501

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vtls: fix static function name collisions between TLS backends

When using CMake Unity build.

- use unique name for `set_ssl_version_min_max()`
Fixes collision between GnuTLS,

vtls: fix static function name collisions between TLS backends

When using CMake Unity build.

- use unique name for `set_ssl_version_min_max()`
Fixes collision between GnuTLS, mbedTLS and SecureTransport.
```
lib\vtls\mbedtls.c(317,1): error C2084: function 'CURLcode set_ssl_version_min_max(Curl_easy *,ssl_peer *,ssl_primary_config *,const char **,const char *)' already has a body
lib\vtls\mbedtls.c(837,49): warning C4133: 'function': incompatible types - from 'Curl_cfilter *' to 'Curl_easy *'
lib\vtls\mbedtls.c(837,53): warning C4133: 'function': incompatible types - from 'Curl_easy *' to 'ssl_peer *'
lib\vtls\mbedtls.c(837,25): error C2198: 'set_ssl_version_min_max': too few arguments for call
```

- use unique name for `do_file_type()`
Fixes collision between GnuTLS, OpenSSL and wolfSSL.
```
lib\vtls\openssl.c(1053,12): error C2084: function 'gnutls_x509_crt_fmt_t do_file_type(const char *)' already has a body
```

Ref: https://github.com/curl/curl/actions/runs/10341162641/job/28622681573?pr=14484#step:10:31
Cherry-picked from #14495
Closes #14516

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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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http2: improved upload eos handling

- replace the counting of upload lengths with the new eos send flag
- improve frequency of stream draining to happen less on events where it
is

http2: improved upload eos handling

- replace the counting of upload lengths with the new eos send flag
- improve frequency of stream draining to happen less on events where it
is not needed
- this PR is based on #14220

http2, cf-h2-proxy: fix EAGAINed out buffer
- in adjust pollset and shutdown handling, a non-empty `ctx->outbufq`
must trigger send polling, irregardless of http/2 flow control
- in http2, fix retry handling of blocked GOAWAY frame

test case improvement:
- let client 'upload-pausing' handle http versions

Closes #14253

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lib: add eos flag to send methods

Adds a `bool eos` flag to send methods to indicate that the data
is the last chunk the invovled transfer wants to send to the server.

This will

lib: add eos flag to send methods

Adds a `bool eos` flag to send methods to indicate that the data
is the last chunk the invovled transfer wants to send to the server.

This will help protocol filters like HTTP/2 and 3 to forward the
stream's EOF flag and also allow to EAGAIN such calls when buffers
are not yet fully flushed.

Closes #14220

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Revert "lib: send eos flag"

This reverts commit be93299f10ef0b2bf7fe5c82140120073831867a.

lib: send eos flag

Adds a `bool eos` flag to send methods to indicate that the data is the
last chunk the invovled transfer wants to send to the server.

This will help protocol

lib: send eos flag

Adds a `bool eos` flag to send methods to indicate that the data is the
last chunk the invovled transfer wants to send to the server.

This will help protocol filters like HTTP/2 and 3 to forward the
stream's EOF flag and also allow to EAGAIN such calls when buffers are
not yet fully flushed.

Closes #14220

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tidy-up: adjust casing of project names

Mostly TLS/SSH project name.

Closes #14160

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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code: language cleanup in comments

Based on the standards and guidelines we use for our documentation.

- expand contractions (they're => they are etc)
- host name = > hostname

code: language cleanup in comments

Based on the standards and guidelines we use for our documentation.

- expand contractions (they're => they are etc)
- host name = > hostname
- file name => filename
- user name = username
- man page => manpage
- run-time => runtime
- set-up => setup
- back-end => backend
- a HTTP => an HTTP
- Two spaces after a period => one space after period

Closes #14073

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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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gnutls: pass in SNI name, not hostname when checking cert

The function we use is called 'gnutls_x509_crt_check_hostname()' but if
we pass in the hostname with a trailing dot, the check f

gnutls: pass in SNI name, not hostname when checking cert

The function we use is called 'gnutls_x509_crt_check_hostname()' but if
we pass in the hostname with a trailing dot, the check fails. If we pass
in the SNI name, which cannot have a trailing dot, it succeeds for
https://pyropus.ca./

I consider this as a flaw in GnuTLS and have submitted this issue
upstream:

https://gitlab.com/gnutls/gnutls/-/issues/1548

In order to work with old and existing GnuTLS versions, we still need
this change no matter how they view the issue or might change it in the
future.

Fixes #13428
Reported-by: Ryan Carsten Schmidt
Closes #13949

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lib: xfer_setup and non-blocking shutdown

- clarify Curl_xfer_setup() with RECV/SEND flags and different calls for
which socket they operate on. Add a shutdown flag for secondary

lib: xfer_setup and non-blocking shutdown

- clarify Curl_xfer_setup() with RECV/SEND flags and different calls for
which socket they operate on. Add a shutdown flag for secondary
sockets
- change Curl_xfer_setup() calls to new functions
- implement non-blocking connection shutdown at the end of receiving or
sending a transfer

Closes #13913

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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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gnutls: support CA caching

- similar to openssl, use a shared 'credentials' instance
among TLS connections with a plain configuration.
- different to openssl, a connection with a c

gnutls: support CA caching

- similar to openssl, use a shared 'credentials' instance
among TLS connections with a plain configuration.
- different to openssl, a connection with a client certificate
is not eligible to sharing.
- document CURLOPT_CA_CACHE_TIMEOUT in man page

Closes #13795

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lib/v*: tidy up types and casts

Also add a couple of negative checks.

Cherry-picked from #13489
Closes #13622

openssl/gnutls: rectify the TLS version checks for QUIC

The versions check wrongly complained and return error if the *minimum*
version was set to something less than 1.3. QUIC is always

openssl/gnutls: rectify the TLS version checks for QUIC

The versions check wrongly complained and return error if the *minimum*
version was set to something less than 1.3. QUIC is always TLS 1.3, but
that means minimum 1.2 is still fine to ask for.

This also renames the local variable to make the mistake harder to make
in the future.

Regression shipped in 8.8.0

Follow-up to 3210101088dfa3d6a125

Reported-by: fds242 on github
Fixes #13799
Closes #13802

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gnutls: improve TLS shutdown

local ftp upload tests sometimes failed with an invalid TLS record being
reported by gnutls. vsftp did log that the shutdown was not regarded as
clean, f

gnutls: improve TLS shutdown

local ftp upload tests sometimes failed with an invalid TLS record being
reported by gnutls. vsftp did log that the shutdown was not regarded as
clean, failing the control connection thereafter.

These changes make test_31_05 work reliable locally.

- on closing the SSL filter, shutdown READ *and* WRITE
- on closing, try a receive after shutdown is sent
- convert to DEBUGF to CURL_TRC_CF

Closes #13790

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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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