citadel/modules/openid/serv_openid_rp.c

   1 /*
   2  * $Id$
   3  *
   4  * OpenID 1.1 "relying party" implementation
   5  *
   6  */
   7
   8 #include "sysdep.h"
   9 #include <stdlib.h>
  10 #include <unistd.h>
  11 #include <stdio.h>
  12 #include <fcntl.h>
  13 #include <signal.h>
  14 #include <pwd.h>
  15 #include <errno.h>
  16 #include <sys/types.h>
  17
  18 #if TIME_WITH_SYS_TIME
  19 # include <sys/time.h>
  20 # include <time.h>
  21 #else
  22 # if HAVE_SYS_TIME_H
  23 #  include <sys/time.h>
  24 # else
  25 #  include <time.h>
  26 # endif
  27 #endif
  28
  29 #include <sys/wait.h>
  30 #include <string.h>
  31 #include <limits.h>
  32 #include <curl/curl.h>
  33 #include "ctdl_module.h"
  34
  35
  36 /*
  37  * Locate a <link> tag and, given its 'rel=' parameter, return its 'href' parameter
  38  */
  39 void extract_link(char *target_buf, int target_size, char *rel, char *source_buf)
  40 {
  41         char *ptr = source_buf;
  42
  43         if (!target_buf) return;
  44         if (!rel) return;
  45         if (!source_buf) return;
  46
  47         target_buf[0] = 0;
  48
  49         while (ptr = bmstrcasestr(ptr, "<link"), ptr != NULL) {
  50
  51                 char work_buffer[1024];
  52                 char *link_tag_start = NULL;
  53                 char *link_tag_end = NULL;
  54
  55                 char rel_tag[1024];
  56                 char href_tag[1024];
  57
  58                 link_tag_start = ptr;
  59                 link_tag_end = strchr(ptr, '>');
  60                 rel_tag[0] = 0;
  61                 href_tag[0] = 0;
  62
  63                 if ((link_tag_end) && (link_tag_end > link_tag_start)) {
  64                         int len;
  65                         len = link_tag_end - link_tag_start;
  66                         if (len > sizeof work_buffer) len = sizeof work_buffer;
  67                         memcpy(work_buffer, link_tag_start, len);
  68
  69                         char *rel_start = NULL;
  70                         char *rel_end = NULL;
  71                         rel_start = bmstrcasestr(work_buffer, "rel=");
  72                         if (rel_start) {
  73                                 rel_start = strchr(rel_start, '\"');
  74                                 if (rel_start) {
  75                                         ++rel_start;
  76                                         rel_end = strchr(rel_start, '\"');
  77                                         if ((rel_end) && (rel_end > rel_start)) {
  78                                                 safestrncpy(rel_tag, rel_start, rel_end - rel_start + 1);
  79                                         }
  80                                 }
  81                         }
  82
  83                         char *href_start = NULL;
  84                         char *href_end = NULL;
  85                         href_start = bmstrcasestr(work_buffer, "href=");
  86                         if (href_start) {
  87                                 href_start = strchr(href_start, '\"');
  88                                 if (href_start) {
  89                                         ++href_start;
  90                                         href_end = strchr(href_start, '\"');
  91                                         if ((href_end) && (href_end > href_start)) {
  92                                                 safestrncpy(href_tag, href_start, href_end - href_start + 1);
  93                                         }
  94                                 }
  95                         }
  96
  97                         if (!strcasecmp(rel, rel_tag)) {
  98                                 safestrncpy(target_buf, href_tag, target_size);
  99                                 return;
 100                         }
 101
 102                 }
 103
 104         ++ptr;
 105         }
 106
 107
 108 }
 109
 110
 111
 112 struct fh_data {
 113         char *buf;
 114         int total_bytes_received;
 115         int maxbytes;
 116 };
 117
 118
 119 size_t fh_callback(void *ptr, size_t size, size_t nmemb, void *stream)
 120 {
 121         struct fh_data *fh = (struct fh_data *) stream;
 122         int got_bytes = (size * nmemb);
 123
 124         if (fh->total_bytes_received + got_bytes > fh->maxbytes) {
 125                 got_bytes = fh->maxbytes - fh->total_bytes_received;
 126         }
 127         if (got_bytes > 0) {
 128                 memcpy(&fh->buf[fh->total_bytes_received], ptr, got_bytes);
 129                 fh->total_bytes_received += got_bytes;
 130         }
 131
 132         return got_bytes;
 133 }
 134
 135
 136
 137 /*
 138  * Begin an HTTP fetch (returns number of bytes actually fetched, or -1 for error)
 139  * We first try 'curl' or 'wget' because they have more robust HTTP handling, and also
 140  * support HTTPS.  If neither one works, we fall back to a built in mini HTTP client.
 141  */
 142 int fetch_http(char *url, char *target_buf, int maxbytes)
 143 {
 144         CURL *curl;
 145         CURLcode res;
 146         char errmsg[1024] = "";
 147         struct fh_data fh = {
 148                 target_buf,
 149                 0,
 150                 maxbytes
 151         };
 152
 153         if (!url) return(-1);
 154         if (!target_buf) return(-1);
 155         memset(target_buf, 0, maxbytes);
 156
 157         curl = curl_easy_init();
 158         if (!curl) {
 159                 CtdlLogPrintf(CTDL_ALERT, "Unable to initialize libcurl.\n");
 160                 return(-1);
 161         }
 162
 163         curl_easy_setopt(curl, CURLOPT_URL, url);
 164         curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0);
 165         curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0);
 166         curl_easy_setopt(curl, CURLOPT_WRITEDATA, &fh);
 167         curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, fh_callback);
 168         curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, errmsg);
 169         curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1);
 170
 171         res = curl_easy_perform(curl);
 172         if (res) {
 173                 CtdlLogPrintf(CTDL_ALERT, "libcurl error %d: %s\n", res, errmsg);
 174         }
 175
 176         curl_easy_cleanup(curl);
 177         return fh.total_bytes_received;
 178 }
 179
 180
 181
 182
 183 /*
 184  * Begin the first portion of an OpenID checkid_setup operation.
 185  */
 186 void cmd_oid1(char *argbuf) {
 187         char openid_url[1024];
 188         char return_to[1024];
 189         char trust_root[1024];
 190         int i;
 191         char buf[SIZ];
 192
 193         if (CC->logged_in) {
 194                 cprintf("%d Already logged in.\n", ERROR + ALREADY_LOGGED_IN);
 195                 return;
 196         }
 197
 198         extract_token(openid_url, argbuf, 0, '|', sizeof openid_url);
 199         extract_token(return_to, argbuf, 1, '|', sizeof return_to);
 200         extract_token(trust_root, argbuf, 2, '|', sizeof trust_root);
 201
 202         i = fetch_http(openid_url, buf, sizeof buf - 1);
 203         buf[sizeof buf - 1] = 0;
 204         CtdlLogPrintf(CTDL_DEBUG, "fetch got %d bytes:\n", i);
 205         if (i > 0) {
 206                 char openid_server[1024];
 207                 char openid_delegate[1024];
 208
 209                 extract_link(openid_server, sizeof openid_server, "openid.server", buf);
 210                 extract_link(openid_delegate, sizeof openid_delegate, "openid.delegate", buf);
 211
 212                 if (IsEmptyStr(openid_server)) {
 213                         cprintf("%d There is no OpenID identity provider at this URL.\n", ERROR);
 214                         return;
 215                 }
 216
 217                 /* Empty delegate is legal; we just use the openid_url instead */
 218                 if (IsEmptyStr(openid_delegate)) {
 219                         safestrncpy(openid_delegate, openid_url, sizeof openid_delegate);
 220                 }
 221
 222                 /* Now we know where to redirect to. */
 223
 224                 char redirect_string[4096];
 225                 char escaped_identity[1024];
 226                 char escaped_return_to[1024];
 227                 char escaped_trust_root[1024];
 228
 229                 urlesc(escaped_identity, sizeof escaped_identity, openid_delegate);
 230                 urlesc(escaped_return_to, sizeof escaped_return_to, return_to);
 231                 urlesc(escaped_trust_root, sizeof escaped_trust_root, trust_root);
 232
 233                 snprintf(redirect_string, sizeof redirect_string,
 234                         "%s"
 235                         "?openid.mode=checkid_setup"
 236                         "&openid_identity=%s"
 237                         "&openid.return_to=%s"
 238                         "&openid.trust_root=%s"
 239                         ,
 240                         openid_server, escaped_identity, escaped_return_to, escaped_trust_root
 241                 );
 242                 cprintf("%d %s\n", CIT_OK, redirect_string);
 243                 return;
 244         }
 245
 246         cprintf("%d Unable to fetch OpenID URL\n", ERROR);
 247 }
 248
 249
 250
 251
 252
 253 /* To insert this module into the server activate the next block by changing the #if 0 to #if 1 */
 254 CTDL_MODULE_INIT(openid_rp)
 255 {
 256         if (!threading)
 257         {
 258                 CtdlRegisterProtoHook(cmd_oid1, "OID1", "Begin OpenID checkid_setup operation");
 259         }
 260
 261    /* return our Subversion id for the Log */
 262    return "$Id$";
 263 }