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 struct associate_handle {
  37         char claimed_id[256];
  38         char assoc_type[32];
  39         time_t expires_in;
  40         char assoc_handle[128];
  41         char mac_key[128];
  42 };
  43
  44
  45
  46 /*
  47  * Locate a <link> tag and, given its 'rel=' parameter, return its 'href' parameter
  48  */
  49 void extract_link(char *target_buf, int target_size, char *rel, char *source_buf)
  50 {
  51         char *ptr = source_buf;
  52
  53         if (!target_buf) return;
  54         if (!rel) return;
  55         if (!source_buf) return;
  56
  57         target_buf[0] = 0;
  58
  59         while (ptr = bmstrcasestr(ptr, "<link"), ptr != NULL) {
  60
  61                 char work_buffer[1024];
  62                 char *link_tag_start = NULL;
  63                 char *link_tag_end = NULL;
  64
  65                 char rel_tag[1024];
  66                 char href_tag[1024];
  67
  68                 link_tag_start = ptr;
  69                 link_tag_end = strchr(ptr, '>');
  70                 rel_tag[0] = 0;
  71                 href_tag[0] = 0;
  72
  73                 if ((link_tag_end) && (link_tag_end > link_tag_start)) {
  74                         int len;
  75                         len = link_tag_end - link_tag_start;
  76                         if (len > sizeof work_buffer) len = sizeof work_buffer;
  77                         memcpy(work_buffer, link_tag_start, len);
  78
  79                         char *rel_start = NULL;
  80                         char *rel_end = NULL;
  81                         rel_start = bmstrcasestr(work_buffer, "rel=");
  82                         if (rel_start) {
  83                                 rel_start = strchr(rel_start, '\"');
  84                                 if (rel_start) {
  85                                         ++rel_start;
  86                                         rel_end = strchr(rel_start, '\"');
  87                                         if ((rel_end) && (rel_end > rel_start)) {
  88                                                 safestrncpy(rel_tag, rel_start, rel_end - rel_start + 1);
  89                                         }
  90                                 }
  91                         }
  92
  93                         char *href_start = NULL;
  94                         char *href_end = NULL;
  95                         href_start = bmstrcasestr(work_buffer, "href=");
  96                         if (href_start) {
  97                                 href_start = strchr(href_start, '\"');
  98                                 if (href_start) {
  99                                         ++href_start;
 100                                         href_end = strchr(href_start, '\"');
 101                                         if ((href_end) && (href_end > href_start)) {
 102                                                 safestrncpy(href_tag, href_start, href_end - href_start + 1);
 103                                         }
 104                                 }
 105                         }
 106
 107                         if (!strcasecmp(rel, rel_tag)) {
 108                                 safestrncpy(target_buf, href_tag, target_size);
 109                                 return;
 110                         }
 111
 112                 }
 113
 114         ++ptr;
 115         }
 116
 117
 118 }
 119
 120
 121
 122 struct fh_data {
 123         char *buf;
 124         int total_bytes_received;
 125         int maxbytes;
 126 };
 127
 128
 129 size_t fh_callback(void *ptr, size_t size, size_t nmemb, void *stream)
 130 {
 131         struct fh_data *fh = (struct fh_data *) stream;
 132         int got_bytes = (size * nmemb);
 133
 134         if (fh->total_bytes_received + got_bytes > fh->maxbytes) {
 135                 got_bytes = fh->maxbytes - fh->total_bytes_received;
 136         }
 137         if (got_bytes > 0) {
 138                 memcpy(&fh->buf[fh->total_bytes_received], ptr, got_bytes);
 139                 fh->total_bytes_received += got_bytes;
 140         }
 141
 142         return got_bytes;
 143 }
 144
 145
 146
 147 /*
 148  * Begin an HTTP fetch (returns number of bytes actually fetched, or -1 for error)
 149  * We first try 'curl' or 'wget' because they have more robust HTTP handling, and also
 150  * support HTTPS.  If neither one works, we fall back to a built in mini HTTP client.
 151  */
 152 int fetch_http(char *url, char *target_buf, int maxbytes)
 153 {
 154         CURL *curl;
 155         CURLcode res;
 156         char errmsg[1024] = "";
 157         struct fh_data fh = {
 158                 target_buf,
 159                 0,
 160                 maxbytes
 161         };
 162
 163         if (!url) return(-1);
 164         if (!target_buf) return(-1);
 165         memset(target_buf, 0, maxbytes);
 166
 167         curl = curl_easy_init();
 168         if (!curl) {
 169                 CtdlLogPrintf(CTDL_ALERT, "Unable to initialize libcurl.\n");
 170                 return(-1);
 171         }
 172
 173         curl_easy_setopt(curl, CURLOPT_URL, url);
 174         curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0);
 175         curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0);
 176         curl_easy_setopt(curl, CURLOPT_WRITEDATA, &fh);
 177         curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, fh_callback);
 178         curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, errmsg);
 179         curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1);
 180
 181         res = curl_easy_perform(curl);
 182         if (res) {
 183                 CtdlLogPrintf(CTDL_ALERT, "libcurl error %d: %s\n", res, errmsg);
 184         }
 185
 186         curl_easy_cleanup(curl);
 187         return fh.total_bytes_received;
 188 }
 189
 190
 191 #define ASSOCIATE_RESPONSE_SIZE 4096
 192
 193 /*
 194  * libcurl callback function for prepare_openid_associate_request()
 195  */
 196 size_t associate_callback(void *ptr, size_t size, size_t nmemb, void *stream)
 197 {
 198         char *response = (char *) stream;
 199         int got_bytes = (size * nmemb);
 200         int len = strlen(response);
 201
 202         if ((len + got_bytes + 1) < ASSOCIATE_RESPONSE_SIZE) {
 203                 memcpy(&response[len], ptr, got_bytes);
 204                 response[len+got_bytes] = 0;
 205         }
 206
 207         return got_bytes;
 208 }
 209
 210
 211 /*
 212  * Process the response from an "associate" request
 213  */
 214 struct associate_handle *process_associate_response(char *claimed_id, char *associate_response)
 215 {
 216         struct associate_handle *h = NULL;
 217
 218         h = (struct associate_handle *) malloc(sizeof(struct associate_handle));
 219         safestrncpy(h->claimed_id, claimed_id, sizeof h->claimed_id);
 220
 221
 222
 223
 224         // FIXME finish this
 225
 226
 227         return h;
 228 }
 229
 230
 231
 232 /*
 233  * Establish a shared secret with an OpenID Identity Provider by sending
 234  * an "associate" request.
 235  */
 236 struct associate_handle *prepare_openid_associate_request(
 237                 char *claimed_id, char *openid_server, char *openid_delegate)
 238 {
 239         CURL *curl;
 240         CURLcode res;
 241         struct curl_httppost *formpost=NULL;
 242         struct curl_httppost *lastptr=NULL;
 243         char associate_response[ASSOCIATE_RESPONSE_SIZE];
 244         struct associate_handle *h = NULL;
 245
 246         memset(associate_response, 0, ASSOCIATE_RESPONSE_SIZE);
 247
 248         curl_formadd(&formpost,
 249                         &lastptr,
 250                         CURLFORM_COPYNAME,      "openid.mode",
 251                         CURLFORM_COPYCONTENTS,  "associate",
 252                         CURLFORM_END
 253         );
 254
 255         curl_formadd(&formpost,
 256                         &lastptr,
 257                         CURLFORM_COPYNAME,      "openid.session_type",
 258                         CURLFORM_COPYCONTENTS,  "",
 259                         CURLFORM_END
 260         );
 261
 262         curl = curl_easy_init();
 263         if (curl) {
 264                 curl_easy_setopt(curl, CURLOPT_URL, openid_server);
 265                 curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0);
 266                 curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0);
 267                 curl_easy_setopt(curl, CURLOPT_WRITEDATA, associate_response);
 268                 curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, associate_callback);
 269                 curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1);
 270
 271                 curl_easy_setopt(curl, CURLOPT_HTTPPOST, formpost);
 272                 res = curl_easy_perform(curl);
 273                 h = process_associate_response(claimed_id, associate_response);
 274                 curl_easy_cleanup(curl);
 275         }
 276         curl_formfree(formpost);
 277
 278         return h;
 279 }
 280
 281
 282
 283
 284
 285 /*
 286  * Begin the first portion of an OpenID checkid_setup operation.
 287  */
 288 void cmd_oid1(char *argbuf) {
 289         char openid_url[1024];
 290         char return_to[1024];
 291         char trust_root[1024];
 292         int i;
 293         char buf[SIZ];
 294         struct associate_handle *h = NULL;
 295
 296         if (CC->logged_in) {
 297                 cprintf("%d Already logged in.\n", ERROR + ALREADY_LOGGED_IN);
 298                 return;
 299         }
 300
 301         extract_token(openid_url, argbuf, 0, '|', sizeof openid_url);
 302         extract_token(return_to, argbuf, 1, '|', sizeof return_to);
 303         extract_token(trust_root, argbuf, 2, '|', sizeof trust_root);
 304
 305         i = fetch_http(openid_url, buf, sizeof buf - 1);
 306         buf[sizeof buf - 1] = 0;
 307         if (i > 0) {
 308                 char openid_server[1024];
 309                 char openid_delegate[1024];
 310
 311                 extract_link(openid_server, sizeof openid_server, "openid.server", buf);
 312                 extract_link(openid_delegate, sizeof openid_delegate, "openid.delegate", buf);
 313
 314                 if (IsEmptyStr(openid_server)) {
 315                         cprintf("%d There is no OpenID identity provider at this URL.\n", ERROR);
 316                         return;
 317                 }
 318
 319                 /* Empty delegate is legal; we just use the openid_url instead */
 320                 if (IsEmptyStr(openid_delegate)) {
 321                         safestrncpy(openid_delegate, openid_url, sizeof openid_delegate);
 322                 }
 323
 324                 /* Prepare an "associate" request */
 325                 h = prepare_openid_associate_request(openid_url, openid_server, openid_delegate);
 326
 327                 /* Now we know where to redirect to. */
 328                 char redirect_string[4096];
 329                 char escaped_identity[1024];
 330                 char escaped_return_to[1024];
 331                 char escaped_trust_root[1024];
 332                 char escaped_sreg_optional[256];
 333
 334                 urlesc(escaped_identity, sizeof escaped_identity, openid_delegate);
 335                 urlesc(escaped_return_to, sizeof escaped_return_to, return_to);
 336                 urlesc(escaped_trust_root, sizeof escaped_trust_root, trust_root);
 337                 urlesc(escaped_sreg_optional, sizeof escaped_sreg_optional,
 338                         "nickname,email,fullname,postcode,country");
 339
 340                 snprintf(redirect_string, sizeof redirect_string,
 341                         "%s"
 342                         "?openid.mode=checkid_setup"
 343                         "&openid_identity=%s"
 344                         "&openid.return_to=%s"
 345                         "&openid.trust_root=%s"
 346                         "&openid.sreg.optional=%s"
 347                         ,
 348                         openid_server, escaped_identity, escaped_return_to,
 349                         escaped_trust_root, escaped_sreg_optional
 350                 );
 351                 cprintf("%d %s\n", CIT_OK, redirect_string);
 352                 return;
 353         }
 354
 355         cprintf("%d Unable to fetch OpenID URL\n", ERROR);
 356 }
 357
 358
 359
 360
 361
 362 /* To insert this module into the server activate the next block by changing the #if 0 to #if 1 */
 363 CTDL_MODULE_INIT(openid_rp)
 364 {
 365         if (!threading)
 366         {
 367                 curl_global_init(CURL_GLOBAL_ALL);
 368                 CtdlRegisterProtoHook(cmd_oid1, "OID1", "Begin OpenID checkid_setup operation");
 369         }
 370
 371    /* return our Subversion id for the Log */
 372    return "$Id$";
 373 }