curl/docs/libcurl/opts/CURLOPT_PROXY_CRLFILE.3
Alex Rousskov cb4e2be7c6 proxy: Support HTTPS proxy and SOCKS+HTTP(s)
* HTTPS proxies:

An HTTPS proxy receives all transactions over an SSL/TLS connection.
Once a secure connection with the proxy is established, the user agent
uses the proxy as usual, including sending CONNECT requests to instruct
the proxy to establish a [usually secure] TCP tunnel with an origin
server. HTTPS proxies protect nearly all aspects of user-proxy
communications as opposed to HTTP proxies that receive all requests
(including CONNECT requests) in vulnerable clear text.

With HTTPS proxies, it is possible to have two concurrent _nested_
SSL/TLS sessions: the "outer" one between the user agent and the proxy
and the "inner" one between the user agent and the origin server
(through the proxy). This change adds supports for such nested sessions
as well.

A secure connection with a proxy requires its own set of the usual SSL
options (their actual descriptions differ and need polishing, see TODO):

  --proxy-cacert FILE        CA certificate to verify peer against
  --proxy-capath DIR         CA directory to verify peer against
  --proxy-cert CERT[:PASSWD] Client certificate file and password
  --proxy-cert-type TYPE     Certificate file type (DER/PEM/ENG)
  --proxy-ciphers LIST       SSL ciphers to use
  --proxy-crlfile FILE       Get a CRL list in PEM format from the file
  --proxy-insecure           Allow connections to proxies with bad certs
  --proxy-key KEY            Private key file name
  --proxy-key-type TYPE      Private key file type (DER/PEM/ENG)
  --proxy-pass PASS          Pass phrase for the private key
  --proxy-ssl-allow-beast    Allow security flaw to improve interop
  --proxy-sslv2              Use SSLv2
  --proxy-sslv3              Use SSLv3
  --proxy-tlsv1              Use TLSv1
  --proxy-tlsuser USER       TLS username
  --proxy-tlspassword STRING TLS password
  --proxy-tlsauthtype STRING TLS authentication type (default SRP)

All --proxy-foo options are independent from their --foo counterparts,
except --proxy-crlfile which defaults to --crlfile and --proxy-capath
which defaults to --capath.

Curl now also supports %{proxy_ssl_verify_result} --write-out variable,
similar to the existing %{ssl_verify_result} variable.

Supported backends: OpenSSL, GnuTLS, and NSS.

* A SOCKS proxy + HTTP/HTTPS proxy combination:

If both --socks* and --proxy options are given, Curl first connects to
the SOCKS proxy and then connects (through SOCKS) to the HTTP or HTTPS
proxy.

TODO: Update documentation for the new APIs and --proxy-* options.
Look for "Added in 7.XXX" marks.
2016-11-24 23:41:44 +01:00

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.TH CURLOPT_PROXY_CRLFILE 3 "16 Nov 2016" "libcurl 7.51.1" "curl_easy_setopt options"
.SH NAME
CURLOPT_PROXY_CRLFILE \- specify a proxy Certificate Revocation List file
.SH SYNOPSIS
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_CRLFILE, char *file);
.SH DESCRIPTION
TODO: Make this text specific to HTTPS proxy. (Added in 7.XXX)
Pass a char * to a zero terminated string naming a \fIfile\fP with the
concatenation of CRL (in PEM format) to use in the certificate validation that
occurs during the SSL exchange.
When curl is built to use NSS or GnuTLS, there is no way to influence the use
of CRL passed to help in the verification process. When libcurl is built with
OpenSSL support, X509_V_FLAG_CRL_CHECK and X509_V_FLAG_CRL_CHECK_ALL are both
set, requiring CRL check against all the elements of the certificate chain if
a CRL file is passed.
This option makes sense only when used in combination with the
\fICURLOPT_SSL_VERIFYPEER(3)\fP option.
A specific error code (\fICURLE_SSL_CRL_BADFILE\fP) is defined with the
option. It is returned when the SSL exchange fails because the CRL file cannot
be loaded. A failure in certificate verification due to a revocation
information found in the CRL does not trigger this specific error.
.SH DEFAULT
NULL
.SH PROTOCOLS
All TLS-based protocols
.SH EXAMPLE
TODO
.SH AVAILABILITY
Added in 7.51.1
.SH RETURN VALUE
Returns CURLE_OK if the option is supported, CURLE_UNKNOWN_OPTION if not, or
CURLE_OUT_OF_MEMORY if there was insufficient heap space.
.SH "SEE ALSO"
.BR CURLOPT_SSL_VERIFYPEER "(3), " CURLOPT_SSL_VERIFYHOST "(3), "