hsts: add read/write callbacks

- read/write callback options
- man pages for the 4 new setopts
- test 1915 verifies the callbacks

Closes #5896

8 files changed, 314 insertions, 0 deletions

diff --git a/docs/libcurl/curl_easy_setopt.3 b/docs/libcurl/curl_easy_setopt.3
index 3434b158c..9403304b8 100644
--- a/docs/libcurl/curl_easy_setopt.3
+++ b/docs/libcurl/curl_easy_setopt.3
@@ -323,6 +323,14 @@ Enable and configure Alt-Svc: treatment. See \fICURLOPT_ALTSVC_CTRL(3)\fP
 Set HSTS cache file. See \fICURLOPT_HSTS(3)\fP
 .IP CURLOPT_HSTS_CTRL
 Enable HSTS. See \fICURLOPT_HSTS_CTRL(3)\fP
+.IP CURLOPT_HSTSREADFUNCTION
+Set HSTS read callback. See \fICURLOPT_HSTSREADFUNCTION(3)\fP
+.IP CURLOPT_HSTSREADDATA
+Pass pointer to the HSTS read callback. See \fICURLOPT_HSTSREADDATA(3)\fP
+.IP CURLOPT_HSTSWRITEFUNCTION
+Set HSTS write callback. See \fICURLOPT_HSTSWRITEFUNCTION(3)\fP
+.IP CURLOPT_HSTSWRITEDATA
+Pass pointer to the HSTS write callback. See \fICURLOPT_HSTSWRITEDATA(3)\fP
 .IP CURLOPT_HTTPGET
 Do an HTTP GET request. See \fICURLOPT_HTTPGET(3)\fP
 .IP CURLOPT_REQUEST_TARGET
diff --git a/docs/libcurl/opts/CURLOPT_HSTSREADDATA.3 b/docs/libcurl/opts/CURLOPT_HSTSREADDATA.3
new file mode 100644
index 000000000..1af2d191e
--- /dev/null
+++ b/docs/libcurl/opts/CURLOPT_HSTSREADDATA.3
@@ -0,0 +1,66 @@
+.\" **************************************************************************
+.\" *                                  _   _ ____  _
+.\" *  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_HSTSREADDATA 3 "14 Sep 2020" "libcurl 7.74.0" "curl_easy_setopt options"
+.SH NAME
+CURLOPT_HSTSREADDATA \- pointer passed to the HSTS read callback
+.SH SYNOPSIS
+#include <curl/curl.h>
+
+CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HSTSREADDATA, void *pointer);
+.SH EXPERIMENTAL
+Warning: this feature is early code and is marked as experimental. It can only
+be enabled by explicitly telling configure with \fB--enable-hsts\fP. You are
+advised to not ship this in production before the experimental label is
+removed.
+.SH DESCRIPTION
+Data \fIpointer\fP to pass to the HSTS read function. If you use the
+\fICURLOPT_HSTSREADFUNCTION(3)\fP option, this is the pointer you'll get as
+input in the 3rd argument to the callback.
+
+This option doesn't enable HSTS, you need to use \fICURLOPT_HSTS_CTRL(3)\fP to
+do that.
+.SH DEFAULT
+NULL
+.SH PROTOCOLS
+This feature is only used for HTTP(S) transfer.
+.SH EXAMPLE
+.nf
+CURL *curl = curl_easy_init();
+struct MyData this;
+if(curl) {
+  curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");
+
+  /* pass pointer that gets passed in to the
+     CURLOPT_HSTSREADFUNCTION callback */
+  curl_easy_setopt(curl, CURLOPT_HSTSREADDATA, &this);
+
+  curl_easy_perform(curl);
+}
+.fi
+.SH AVAILABILITY
+Added in 7.74.0
+.SH RETURN VALUE
+This will return CURLE_OK.
+.SH "SEE ALSO"
+.BR CURLOPT_HSTSREADFUNCTION "(3), " CURLOPT_HSTSWRITEDATA "(3), "
+.BR CURLOPT_HSTSWRITEFUNCTION "(3), "
diff --git a/docs/libcurl/opts/CURLOPT_HSTSREADFUNCTION.3 b/docs/libcurl/opts/CURLOPT_HSTSREADFUNCTION.3
new file mode 100644
index 000000000..f3f476749
--- /dev/null
+++ b/docs/libcurl/opts/CURLOPT_HSTSREADFUNCTION.3
@@ -0,0 +1,81 @@
+.\" **************************************************************************
+.\" *                                  _   _ ____  _
+.\" *  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_HSTSREADFUNCTION 3 "14 Sep 2020" "libcurl 7.74.0" "curl_easy_setopt options"
+.SH NAME
+CURLOPT_HSTSREADFUNCTION \- read callback for HSTS hosts
+.SH SYNOPSIS
+#include <curl/curl.h>
+
+CURLSTScode hstsread(CURL *easy, struct curl_hstsentry *sts, void *userp);
+
+CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HSTSREADFUNCTION, hstsread);
+.SH EXPERIMENTAL
+Warning: this feature is early code and is marked as experimental. It can only
+be enabled by explicitly telling configure with \fB--enable-hsts\fP. You are
+advised to not ship this in production before the experimental label is
+removed.
+.SH DESCRIPTION
+Pass a pointer to your callback function, as the prototype shows above.
+
+This callback function gets called by libcurl repeatedly when it populates the
+in-memory HSTS cache.
+
+Set the \fIuserp\fP argument with the \fICURLOPT_HSTSREADDATA(3)\fP option or
+it will be NULL.
+
+When this callback is invoked, the \fIsts\fP pointer points to a populated
+struct: Copy the host name to 'name' (no longer than 'namelen' bytes). Make it
+null-terminated. Set 'includeSubDomains' to TRUE or FALSE. Set 'expire' to a
+date stamp or a zero length string for *forever* (wrong date stamp format
+might cause the name to not get accepted)
+
+The callback should return \fICURLSTS_OK\fP if it returns a name and is
+prepared to be called again (for another host) or \fICURLSTS_DONE\fP if it has
+no entry to return. It can also return \fICURLSTS_FAIL\fP to signal error.
+
+This option doesn't enable HSTS, you need to use \fICURLOPT_HSTS_CTRL(3)\fP to
+do that.
+.SH DEFAULT
+NULL - no callback.
+.SH PROTOCOLS
+This feature is only used for HTTP(S) transfer.
+.SH EXAMPLE
+.nf
+{
+  /* set HSTS read callback */
+  curl_easy_setopt(curl, CURLOPT_HSTSREADFUNCTION, hstsread);
+
+  /* pass in suitable argument to the callback */
+  curl_easy_setopt(curl, CURLOPT_HSTSREADDATA, &hstspreload[0]);
+
+  result = curl_easy_perform(curl);
+}
+.fi
+.SH AVAILABILITY
+Added in 7.74.0
+.SH RETURN VALUE
+This will return CURLE_OK.
+.SH "SEE ALSO"
+.BR CURLOPT_HSTSREADDATA "(3), " CURLOPT_HSTSWRITEFUNCTION "(3), "
+.BR CURLOPT_HSTS "(3), " CURLOPT_HSTS_CTRL "(3), "
+
diff --git a/docs/libcurl/opts/CURLOPT_HSTSWRITEDATA.3 b/docs/libcurl/opts/CURLOPT_HSTSWRITEDATA.3
new file mode 100644
index 000000000..9a3e4b769
--- /dev/null
+++ b/docs/libcurl/opts/CURLOPT_HSTSWRITEDATA.3
@@ -0,0 +1,66 @@
+.\" **************************************************************************
+.\" *                                  _   _ ____  _
+.\" *  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_HSTSWRITEDATA 3 "14 Sep 2020" "libcurl 7.74.0" "curl_easy_setopt options"
+.SH NAME
+CURLOPT_HSTSWRITEDATA \- pointer passed to the HSTS write callback
+.SH SYNOPSIS
+#include <curl/curl.h>
+
+CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HSTSWRITEDATA, void *pointer);
+.SH EXPERIMENTAL
+Warning: this feature is early code and is marked as experimental. It can only
+be enabled by explicitly telling configure with \fB--enable-hsts\fP. You are
+advised to not ship this in production before the experimental label is
+removed.
+.SH DESCRIPTION
+Data \fIpointer\fP to pass to the HSTS write function. If you use the
+\fICURLOPT_HSTSWRITEFUNCTION(3)\fP option, this is the pointer you'll get as
+input in the 4th argument to the callback.
+
+This option doesn't enable HSTS, you need to use \fICURLOPT_HSTS_CTRL(3)\fP to
+do that.
+.SH DEFAULT
+NULL
+.SH PROTOCOLS
+This feature is only used for HTTP(S) transfer.
+.SH EXAMPLE
+.nf
+CURL *curl = curl_easy_init();
+struct MyData this;
+if(curl) {
+  curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");
+
+  /* pass pointer that gets passed in to the
+     CURLOPT_HSTSWRITEFUNCTION callback */
+  curl_easy_setopt(curl, CURLOPT_HSTSWRITEDATA, &this);
+
+  curl_easy_perform(curl);
+}
+.fi
+.SH AVAILABILITY
+Added in 7.74.0
+.SH RETURN VALUE
+This will return CURLE_OK.
+.SH "SEE ALSO"
+.BR CURLOPT_HSTSWRITEFUNCTION "(3), " CURLOPT_HSTSREADDATA "(3), "
+.BR CURLOPT_HSTSREADFUNCTION "(3), "
diff --git a/docs/libcurl/opts/CURLOPT_HSTSWRITEFUNCTION.3 b/docs/libcurl/opts/CURLOPT_HSTSWRITEFUNCTION.3
new file mode 100644
index 000000000..ecf1d86f0
--- /dev/null
+++ b/docs/libcurl/opts/CURLOPT_HSTSWRITEFUNCTION.3
@@ -0,0 +1,79 @@
+.\" **************************************************************************
+.\" *                                  _   _ ____  _
+.\" *  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_HSTSWRITEFUNCTION 3 "14 Sep 2020" "libcurl 7.74.0" "curl_easy_setopt options"
+.SH NAME
+CURLOPT_HSTSWRITEFUNCTION \- write callback for HSTS hosts
+.SH SYNOPSIS
+#include <curl/curl.h>
+
+CURLSTScode hstswrite(CURL *easy, struct curl_hstsentry *sts,
+                      struct curl_index *count, void *userp);
+
+CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HSTSWRITEFUNCTION, hstswrite);
+.SH EXPERIMENTAL
+Warning: this feature is early code and is marked as experimental. It can only
+be enabled by explicitly telling configure with \fB--enable-hsts\fP. You are
+advised to not ship this in production before the experimental label is
+removed.
+.SH DESCRIPTION
+Pass a pointer to your callback function, as the prototype shows above.
+
+This callback function gets called by libcurl repeatedly to allow the
+application to store the in-memory HSTS cache when libcurl is about to discard
+it.
+
+Set the \fIuserp\fP argument with the \fICURLOPT_HSTSWRITEDATA(3)\fP option or
+it will be NULL.
+
+When the callback is invoked, the \fIsts\fP pointer points to a populated
+struct: Read the host name to 'name' (it is 'namelen' bytes long and null
+terminated. The 'includeSubDomains' field is non-zero if the entry matches
+subdomains. The 'expire' string is a date stamp null-terminated string using
+the syntax YYYYMMDD HH:MM:SS.
+
+The callback should return \fICURLSTS_OK\fP if it succeeded and is prepared to
+be called again (for another host) or \fICURLSTS_DONE\fP if there's nothing
+more to do. It can also return \fICURLSTS_FAIL\fP to signal error.
+.SH DEFAULT
+NULL - no callback.
+.SH PROTOCOLS
+This feature is only used for HTTP(S) transfer.
+.SH EXAMPLE
+.nf
+{
+  /* set HSTS read callback */
+  curl_easy_setopt(curl, CURLOPT_HSTSWRITEFUNCTION, hstswrite);
+
+  /* pass in suitable argument to the callback */
+  curl_easy_setopt(curl, CURLOPT_HSTSWRITEDATA, &hstspreload[0]);
+
+  result = curl_easy_perform(curl);
+}
+.fi
+.SH AVAILABILITY
+Added in 7.74.0
+.SH RETURN VALUE
+This will return CURLE_OK.
+.SH "SEE ALSO"
+.BR CURLOPT_HSTSWRITEDATA "(3), " CURLOPT_HSTSWRITEFUNCTION "(3), "
+.BR CURLOPT_HSTS "(3), " CURLOPT_HSTS_CTRL "(3), "
diff --git a/docs/libcurl/opts/CURLOPT_WRITEFUNCTION.3 b/docs/libcurl/opts/CURLOPT_WRITEFUNCTION.3
index 03dfca957..3fd458d5d 100644
--- a/docs/libcurl/opts/CURLOPT_WRITEFUNCTION.3
+++ b/docs/libcurl/opts/CURLOPT_WRITEFUNCTION.3
@@ -67,6 +67,9 @@ transfer to become paused.  See \fIcurl_easy_pause(3)\fP for further details.
 Set this option to NULL to get the internal default function used instead of
 your callback. The internal default function will write the data to the FILE *
 given with \fICURLOPT_WRITEDATA(3)\fP.
+
+This option doesn't enable HSTS, you need to use \fICURLOPT_HSTS_CTRL(3)\fP to
+do that.
 .SH DEFAULT
 libcurl will use 'fwrite' as a callback by default.
 .SH PROTOCOLS
diff --git a/docs/libcurl/opts/Makefile.inc b/docs/libcurl/opts/Makefile.inc
index 9d1eb2bba..7bf75ab0a 100644
--- a/docs/libcurl/opts/Makefile.inc
+++ b/docs/libcurl/opts/Makefile.inc
@@ -181,6 +181,10 @@ man_MANS =                                      \
   CURLOPT_HEADERFUNCTION.3                      \
   CURLOPT_HEADEROPT.3                           \
   CURLOPT_HSTS.3                                \
+  CURLOPT_HSTSREADDATA.3                        \
+  CURLOPT_HSTSREADFUNCTION.3                    \
+  CURLOPT_HSTSWRITEDATA.3                       \
+  CURLOPT_HSTSWRITEFUNCTION.3                   \
   CURLOPT_HSTS_CTRL.3                           \
   CURLOPT_HTTP09_ALLOWED.3                      \
   CURLOPT_HTTP200ALIASES.3                      \
diff --git a/docs/libcurl/symbols-in-versions b/docs/libcurl/symbols-in-versions
index cc35fc57b..861aaf88f 100644
--- a/docs/libcurl/symbols-in-versions
+++ b/docs/libcurl/symbols-in-versions
@@ -447,6 +447,10 @@ CURLOPT_HEADERFUNCTION          7.7.2
 CURLOPT_HEADEROPT               7.37.0
 CURLOPT_HSTS                    7.74.0
 CURLOPT_HSTS_CTRL               7.74.0
+CURLOPT_HSTSREADDATA            7.74.0
+CURLOPT_HSTSREADFUNCTION        7.74.0
+CURLOPT_HSTSWRITEDATA           7.74.0
+CURLOPT_HSTSWRITEFUNCTION       7.74.0
 CURLOPT_HTTP09_ALLOWED          7.64.0
 CURLOPT_HTTP200ALIASES          7.10.3
 CURLOPT_HTTPAUTH                7.10.6
@@ -812,6 +816,9 @@ CURLSSLSET_NO_BACKENDS          7.56.0
 CURLSSLSET_OK                   7.56.0
 CURLSSLSET_TOO_LATE             7.56.0
 CURLSSLSET_UNKNOWN_BACKEND      7.56.0
+CURLSTS_DONE                    7.74.0
+CURLSTS_FAIL                    7.74.0
+CURLSTS_OK                      7.74.0
 CURLUE_BAD_HANDLE               7.62.0
 CURLUE_BAD_PARTPOINTER          7.62.0
 CURLUE_BAD_PORT_NUMBER          7.62.0