setopt: add CURLOPT_PROXY_ISSUERCERT(_BLOB) for coherency

Closes #5431

8 files changed, 188 insertions, 0 deletions

diff --git a/docs/libcurl/curl_easy_setopt.3 b/docs/libcurl/curl_easy_setopt.3
index 9692a10b7..a64375e0c 100644
--- a/docs/libcurl/curl_easy_setopt.3
+++ b/docs/libcurl/curl_easy_setopt.3
@@ -564,6 +564,10 @@ Proxy CA cert bundle. See \fICURLOPT_PROXY_CAINFO(3)\fP
 Issuer certificate. See \fICURLOPT_ISSUERCERT(3)\fP
 .IP CURLOPT_ISSUERCERT_BLOB
 Issuer certificate memory buffer. See \fICURLOPT_ISSUERCERT_BLOB(3)\fP
+.IP CURLOPT_PROXY_ISSUERCERT
+Proxy issuer certificate. See \fICURLOPT_PROXY_ISSUERCERT(3)\fP
+.IP CURLOPT_PROXY_ISSUERCERT_BLOB
+Proxy issuer certificate memory buffer. See \fICURLOPT_PROXY_ISSUERCERT_BLOB(3)\fP
 .IP CURLOPT_CAPATH
 Path to CA cert bundle. See \fICURLOPT_CAPATH(3)\fP
 .IP CURLOPT_PROXY_CAPATH
diff --git a/docs/libcurl/opts/CURLOPT_PROXY_ISSUERCERT.3 b/docs/libcurl/opts/CURLOPT_PROXY_ISSUERCERT.3
new file mode 100644
index 000000000..7e9402f08
--- /dev/null
+++ b/docs/libcurl/opts/CURLOPT_PROXY_ISSUERCERT.3
@@ -0,0 +1,73 @@
+.\" **************************************************************************
+.\" *                                  _   _ ____  _
+.\" *  Project                     ___| | | |  _ \| |
+.\" *                             / __| | | | |_) | |
+.\" *                            | (__| |_| |  _ <| |___
+.\" *                             \___|\___/|_| \_\_____|
+.\" *
+.\" * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
+.\" *
+.\" * This software is licensed as described in the file COPYING, which
+.\" * you should have received as part of this distribution. The terms
+.\" * are also available at https://curl.haxx.se/docs/copyright.html.
+.\" *
+.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+.\" * copies of the Software, and permit persons to whom the Software is
+.\" * furnished to do so, under the terms of the COPYING file.
+.\" *
+.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+.\" * KIND, either express or implied.
+.\" *
+.\" **************************************************************************
+.\"
+.TH CURLOPT_PROXY_ISSUERCERT 3 "24 Jun 2020" "libcurl 7.71.0" "curl_easy_setopt options"
+.SH NAME
+CURLOPT_PROXY_ISSUERCERT \- proxy issuer SSL certificate filename
+.SH SYNOPSIS
+#include <curl/curl.h>
+
+CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_ISSUERCERT, char *file);
+.SH DESCRIPTION
+Pass a char * to a zero terminated string naming a \fIfile\fP holding a CA
+certificate in PEM format. If the option is set, an additional check against
+the peer certificate is performed to verify the issuer of the the HTTPS proxy
+is indeed the one associated with the certificate provided by the option.
+This additional check is useful in multi-level PKI where one needs to enforce
+that the peer certificate is from a specific branch of the tree.
+
+This option makes sense only when used in combination with the
+\fICURLOPT_PROXY_SSL_VERIFYPEER(3)\fP option. Otherwise, the result of the
+check is not considered as failure.
+
+A specific error code (CURLE_SSL_ISSUER_ERROR) is defined with the option,
+which is returned if the setup of the SSL/TLS session has failed due to a
+mismatch with the issuer of peer certificate
+(\fICURLOPT_PROXY_SSL_VERIFYPEER(3)\fP has to be set too for the check to
+fail).
+
+The application does not have to keep the string around after setting this
+option.
+.SH DEFAULT
+NULL
+.SH PROTOCOLS
+All TLS-based protocols
+.SH EXAMPLE
+.nf
+CURL *curl = curl_easy_init();
+if(curl) {
+  curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
+  /* using an HTTPS proxy */
+  curl_easy_setopt(curl, CURLOPT_PROXY, "https://localhost:443");
+  curl_easy_setopt(curl, CURLOPT_PROXY_ISSUERCERT, "/etc/certs/cacert.pem");
+  ret = curl_easy_perform(curl);
+  curl_easy_cleanup(curl);
+}
+.fi
+.SH AVAILABILITY
+Added in libcurl 7.71.0. This option is supported by the OpenSSL backends.
+.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_PROXY_SSL_VERIFYPEER "(3), " CURLOPT_PROXY_SSL_VERIFYHOST "(3), "
+.BR CURLOPT_SSL_VERIFYPEER "(3), " CURLOPT_SSL_VERIFYHOST "(3), "
diff --git a/docs/libcurl/opts/CURLOPT_PROXY_ISSUERCERT_BLOB.3 b/docs/libcurl/opts/CURLOPT_PROXY_ISSUERCERT_BLOB.3
new file mode 100644
index 000000000..857fffde9
--- /dev/null
+++ b/docs/libcurl/opts/CURLOPT_PROXY_ISSUERCERT_BLOB.3
@@ -0,0 +1,85 @@
+.\" **************************************************************************
+.\" *                                  _   _ ____  _
+.\" *  Project                     ___| | | |  _ \| |
+.\" *                             / __| | | | |_) | |
+.\" *                            | (__| |_| |  _ <| |___
+.\" *                             \___|\___/|_| \_\_____|
+.\" *
+.\" * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
+.\" *
+.\" * This software is licensed as described in the file COPYING, which
+.\" * you should have received as part of this distribution. The terms
+.\" * are also available at https://curl.haxx.se/docs/copyright.html.
+.\" *
+.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+.\" * copies of the Software, and permit persons to whom the Software is
+.\" * furnished to do so, under the terms of the COPYING file.
+.\" *
+.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+.\" * KIND, either express or implied.
+.\" *
+.\" **************************************************************************
+.\"
+.TH CURLOPT_PROXY_ISSUERCERT_BLOB 3 "24 Jun 2020" "libcurl 7.71.0" "curl_easy_setopt options"
+.SH NAME
+CURLOPT_ISSUERCERT_BLOB \- proxy issuer SSL certificate from memory blob
+.SH SYNOPSIS
+.nf
+#include <curl/curl.h>
+
+CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_ISSUERCERT_BLOB,
+                          struct curl_blob *blob);
+.fi
+.SH DESCRIPTION
+Pass a pointer to a curl_blob struct, which contains information (pointer and
+size) about a memory block with binary data of a CA certificate in PEM
+format. If the option is set, an additional check against the peer certificate
+is performed to verify the issuer of the the HTTPS proxy is indeed the one
+associated with the certificate provided by the option. This additional check
+is useful in multi-level PKI where one needs to enforce that the peer
+certificate is from a specific branch of the tree.
+
+This option should be used in combination with the
+\fICURLOPT_PROXY_SSL_VERIFYPEER(3)\fP option. Otherwise, the result of the
+check is not considered as failure.
+
+A specific error code (CURLE_SSL_ISSUER_ERROR) is defined with the option,
+which is returned if the setup of the SSL/TLS session has failed due to a
+mismatch with the issuer of peer certificate
+(\fICURLOPT_PROXY_SSL_VERIFYPEER(3)\fP has to be set too for the check to
+fail).
+
+If the blob is initialized with the flags member of struct curl_blob set to
+CURL_BLOB_COPY, the application does not have to keep the buffer around after
+setting this.
+
+This option is an alternative to \fICURLOPT_PROXY_ISSUERCERT(3)\fP which
+instead expects a file name as input.
+.SH DEFAULT
+NULL
+.SH PROTOCOLS
+All TLS-based protocols
+.SH EXAMPLE
+.nf
+CURL *curl = curl_easy_init();
+if(curl) {
+  struct curl_blob blob;
+  curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
+  /* using an HTTPS proxy */
+  curl_easy_setopt(curl, CURLOPT_PROXY, "https://localhost:443");
+  blob.data = certificateData;
+  blob.len = filesize;
+  blob.flags = CURL_BLOB_COPY;
+  curl_easy_setopt(curl, CURLOPT_PROXY_ISSUERCERT_BLOB, &blob);
+  ret = curl_easy_perform(curl);
+  curl_easy_cleanup(curl);
+}
+.fi
+.SH AVAILABILITY
+Added in libcurl 7.71.0. This option is supported by the OpenSSL backends.
+.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_PROXY_SSL_VERIFYPEER "(3), " CURLOPT_PROXY_SSL_VERIFYHOST "(3), "
+.BR CURLOPT_SSL_VERIFYPEER "(3), " CURLOPT_SSL_VERIFYHOST "(3), "
diff --git a/docs/libcurl/opts/Makefile.inc b/docs/libcurl/opts/Makefile.inc
index 21e14fc95..c60b486d1 100644
--- a/docs/libcurl/opts/Makefile.inc
+++ b/docs/libcurl/opts/Makefile.inc
@@ -258,6 +258,8 @@ man_MANS =                                      \
   CURLOPT_PROXY_CAPATH.3                        \
   CURLOPT_PROXY_CRLFILE.3                       \
   CURLOPT_PROXY_KEYPASSWD.3                     \
+  CURLOPT_PROXY_ISSUERCERT.3                    \
+  CURLOPT_PROXY_ISSUERCERT_BLOB.3               \
   CURLOPT_PROXY_PINNEDPUBLICKEY.3               \
   CURLOPT_PROXY_SERVICE_NAME.3                  \
   CURLOPT_PROXY_SSLCERT.3                       \
diff --git a/docs/libcurl/symbols-in-versions b/docs/libcurl/symbols-in-versions
index 92159d02a..36126db09 100644
--- a/docs/libcurl/symbols-in-versions
+++ b/docs/libcurl/symbols-in-versions
@@ -516,6 +516,8 @@ CURLOPT_PROGRESSDATA            7.1
 CURLOPT_PROGRESSFUNCTION        7.1           7.32.0
 CURLOPT_PROTOCOLS               7.19.4
 CURLOPT_PROXY                   7.1
+CURLOPT_PROXY_ISSUERCERT        7.71.0
+CURLOPT_PROXY_ISSUERCERT_BLOB   7.71.0
 CURLOPT_PROXYAUTH               7.10.7
 CURLOPT_PROXYHEADER             7.37.0
 CURLOPT_PROXYPASSWORD           7.19.1
diff --git a/include/curl/curl.h b/include/curl/curl.h
index 17d0384f0..d5f8817d5 100644
--- a/include/curl/curl.h
+++ b/include/curl/curl.h
@@ -1967,6 +1967,10 @@ typedef enum {
   CURLOPT(CURLOPT_PROXY_SSLKEY_BLOB, CURLOPTTYPE_BLOB, 294),
   CURLOPT(CURLOPT_ISSUERCERT_BLOB, CURLOPTTYPE_BLOB, 295),
 
+  /* Issuer certificate for proxy */
+  CURLOPT(CURLOPT_PROXY_ISSUERCERT, CURLOPTTYPE_STRINGPOINT, 296),
+  CURLOPT(CURLOPT_PROXY_ISSUERCERT_BLOB, CURLOPTTYPE_BLOB, 297),
+
   CURLOPT_LASTENTRY /* the last unused */
 } CURLoption;
 
diff --git a/lib/setopt.c b/lib/setopt.c
index 4570cc06a..72704127c 100644
--- a/lib/setopt.c
+++ b/lib/setopt.c
@@ -2036,6 +2036,23 @@ CURLcode Curl_vsetopt(struct Curl_easy *data, CURLoption option, va_list param)
     result = Curl_setblobopt(&data->set.blobs[BLOB_SSL_ISSUERCERT_ORIG],
                              va_arg(param, struct curl_blob *));
     break;
+#ifndef CURL_DISABLE_PROXY
+  case CURLOPT_PROXY_ISSUERCERT:
+    /*
+     * Set Issuer certificate file
+     * to check certificates issuer
+     */
+    result = Curl_setstropt(&data->set.str[STRING_SSL_ISSUERCERT_PROXY],
+                            va_arg(param, char *));
+    break;
+  case CURLOPT_PROXY_ISSUERCERT_BLOB:
+    /*
+     * Blob that holds Issuer certificate to check certificates issuer
+     */
+    result = Curl_setblobopt(&data->set.blobs[BLOB_SSL_ISSUERCERT_PROXY],
+                             va_arg(param, struct curl_blob *));
+    break;
+#endif
 #ifndef CURL_DISABLE_TELNET
   case CURLOPT_TELNETOPTIONS:
     /*
diff --git a/lib/urldata.h b/lib/urldata.h
index 9b4ce5f5b..9c50c261f 100644
--- a/lib/urldata.h
+++ b/lib/urldata.h
@@ -1589,6 +1589,7 @@ enum dupblob {
   BLOB_KEY_ORIG,
   BLOB_KEY_PROXY,
   BLOB_SSL_ISSUERCERT_ORIG,
+  BLOB_SSL_ISSUERCERT_PROXY,
   BLOB_LAST
 };