src/ssl_certificate.c

   1 /*
   2  * Sylpheed -- a GTK+ based, lightweight, and fast e-mail client
   3  * Copyright (C) 1999-2001 Hiroyuki Yamamoto
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  18  */
  19
  20 #ifdef HAVE_CONFIG_H
  21 #  include "config.h"
  22 #endif
  23
  24 #if USE_SSL
  25
  26 #include <openssl/ssl.h>
  27 #include <glib.h>
  28 #include "ssl_certificate.h"
  29 #include "alertpanel.h"
  30 #include "utils.h"
  31 #include "intl.h"
  32 #include "prefs_common.h"
  33 #include "socket.h"
  34 #include "log.h"
  35
  36 static char *ssl_certificate_check_signer (X509 *cert);
  37 static SSLCertificate *ssl_certificate_new_lookup(X509 *x509_cert, gchar *host, gushort port, gboolean lookup);
  38
  39 static char * get_fqdn(char *host)
  40 {
  41         struct hostent *hp;
  42
  43         if (host == NULL || strlen(host) == 0)
  44                 return g_strdup("");
  45
  46         hp = my_gethostbyname(host);
  47         if (hp == NULL)
  48                 return g_strdup(host); /*caller should free*/
  49         else
  50                 return g_strdup(hp->h_name);
  51 }
  52
  53 static char * readable_fingerprint(unsigned char *src, int len)
  54 {
  55         int i=0;
  56         char * ret;
  57
  58         if (src == NULL)
  59                 return NULL;
  60         ret = g_strdup("");
  61         while (i < len) {
  62                 char *tmp2;
  63                 if(i>0)
  64                         tmp2 = g_strdup_printf("%s:%02X", ret, src[i]);
  65                 else
  66                         tmp2 = g_strdup_printf("%02X", src[i]);
  67                 g_free(ret);
  68                 ret = g_strdup(tmp2);
  69                 g_free(tmp2);
  70                 i++;
  71         }
  72         return ret;
  73 }
  74
  75 SSLCertificate *ssl_certificate_new(X509 *x509_cert, gchar *host, gushort port)
  76 {
  77         return ssl_certificate_new_lookup(x509_cert, host, port, TRUE);
  78 }
  79
  80 static SSLCertificate *ssl_certificate_new_lookup(X509 *x509_cert, gchar *host, gushort port, gboolean lookup)
  81 {
  82         SSLCertificate *cert = g_new0(SSLCertificate, 1);
  83
  84         if (host == NULL || x509_cert == NULL) {
  85                 ssl_certificate_destroy(cert);
  86                 return NULL;
  87         }
  88         cert->x509_cert = X509_dup(x509_cert);
  89         if (lookup)
  90                 cert->host = get_fqdn(host);
  91         else
  92                 cert->host = g_strdup(host);
  93         cert->port = port;
  94         return cert;
  95 }
  96
  97 static void ssl_certificate_save (SSLCertificate *cert)
  98 {
  99         gchar *file, *port;
 100         FILE *fp;
 101
 102         file = g_strconcat(get_rc_dir(), G_DIR_SEPARATOR_S,
 103                           "certs", G_DIR_SEPARATOR_S, NULL);
 104
 105         if (!is_dir_exist(file))
 106                 make_dir_hier(file);
 107         g_free(file);
 108
 109         port = g_strdup_printf("%d", cert->port);
 110         file = g_strconcat(get_rc_dir(), G_DIR_SEPARATOR_S,
 111                           "certs", G_DIR_SEPARATOR_S,
 112                           cert->host, ".", port, ".cert", NULL);
 113
 114         g_free(port);
 115         fp = fopen(file, "wb");
 116         if (fp == NULL) {
 117                 g_free(file);
 118                 alertpanel_error(_("Can't save certificate !"));
 119                 return;
 120         }
 121         i2d_X509_fp(fp, cert->x509_cert);
 122         g_free(file);
 123         fclose(fp);
 124
 125 }
 126
 127 char* ssl_certificate_to_string(SSLCertificate *cert)
 128 {
 129         char *ret, buf[100];
 130         char *issuer_commonname, *issuer_location, *issuer_organization;
 131         char *subject_commonname, *subject_location, *subject_organization;
 132         char *fingerprint, *sig_status;
 133         unsigned int n;
 134         unsigned char md[EVP_MAX_MD_SIZE];
 135
 136         /* issuer */
 137         if (X509_NAME_get_text_by_NID(X509_get_issuer_name(cert->x509_cert),
 138                                        NID_commonName, buf, 100) >= 0)
 139                 issuer_commonname = g_strdup(buf);
 140         else
 141                 issuer_commonname = g_strdup(_("<not in certificate>"));
 142         if (X509_NAME_get_text_by_NID(X509_get_issuer_name(cert->x509_cert),
 143                                        NID_localityName, buf, 100) >= 0) {
 144                 issuer_location = g_strdup(buf);
 145                 if (X509_NAME_get_text_by_NID(X509_get_issuer_name(cert->x509_cert),
 146                                        NID_countryName, buf, 100) >= 0)
 147                         issuer_location = g_strconcat(issuer_location,", ",buf, NULL);
 148         } else if (X509_NAME_get_text_by_NID(X509_get_issuer_name(cert->x509_cert),
 149                                        NID_countryName, buf, 100) >= 0)
 150                 issuer_location = g_strdup(buf);
 151         else
 152                 issuer_location = g_strdup(_("<not in certificate>"));
 153
 154         if (X509_NAME_get_text_by_NID(X509_get_issuer_name(cert->x509_cert),
 155                                        NID_organizationName, buf, 100) >= 0)
 156                 issuer_organization = g_strdup(buf);
 157         else
 158                 issuer_organization = g_strdup(_("<not in certificate>"));
 159
 160         /* subject */
 161         if (X509_NAME_get_text_by_NID(X509_get_subject_name(cert->x509_cert),
 162                                        NID_commonName, buf, 100) >= 0)
 163                 subject_commonname = g_strdup(buf);
 164         else
 165                 subject_commonname = g_strdup(_("<not in certificate>"));
 166         if (X509_NAME_get_text_by_NID(X509_get_subject_name(cert->x509_cert),
 167                                        NID_localityName, buf, 100) >= 0) {
 168                 subject_location = g_strdup(buf);
 169                 if (X509_NAME_get_text_by_NID(X509_get_subject_name(cert->x509_cert),
 170                                        NID_countryName, buf, 100) >= 0)
 171                         subject_location = g_strconcat(subject_location,", ",buf, NULL);
 172         } else if (X509_NAME_get_text_by_NID(X509_get_subject_name(cert->x509_cert),
 173                                        NID_countryName, buf, 100) >= 0)
 174                 subject_location = g_strdup(buf);
 175         else
 176                 subject_location = g_strdup(_("<not in certificate>"));
 177
 178         if (X509_NAME_get_text_by_NID(X509_get_subject_name(cert->x509_cert),
 179                                        NID_organizationName, buf, 100) >= 0)
 180                 subject_organization = g_strdup(buf);
 181         else
 182                 subject_organization = g_strdup(_("<not in certificate>"));
 183
 184         /* fingerprint */
 185         X509_digest(cert->x509_cert, EVP_md5(), md, &n);
 186         fingerprint = readable_fingerprint(md, (int)n);
 187
 188         /* signature */
 189         sig_status = ssl_certificate_check_signer(cert->x509_cert);
 190
 191         ret = g_strdup_printf(_("  Owner: %s (%s) in %s\n  Signed by: %s (%s) in %s\n  Fingerprint: %s\n  Signature status: %s"),
 192                                 subject_commonname, subject_organization, subject_location,
 193                                 issuer_commonname, issuer_organization, issuer_location,
 194                                 fingerprint,
 195                                 (sig_status==NULL ? "correct":sig_status));
 196
 197         if (issuer_commonname)
 198                 g_free(issuer_commonname);
 199         if (issuer_location)
 200                 g_free(issuer_location);
 201         if (issuer_organization)
 202                 g_free(issuer_organization);
 203         if (subject_commonname)
 204                 g_free(subject_commonname);
 205         if (subject_location)
 206                 g_free(subject_location);
 207         if (subject_organization)
 208                 g_free(subject_organization);
 209         if (fingerprint)
 210                 g_free(fingerprint);
 211         if (sig_status)
 212                 g_free(sig_status);
 213         return ret;
 214 }
 215
 216 void ssl_certificate_destroy(SSLCertificate *cert)
 217 {
 218         if (cert == NULL)
 219                 return;
 220
 221         if (cert->x509_cert)
 222                 X509_free(cert->x509_cert);
 223         if (cert->host)
 224                 g_free(cert->host);
 225         g_free(cert);
 226         cert = NULL;
 227 }
 228
 229 void ssl_certificate_delete_from_disk(SSLCertificate *cert)
 230 {
 231         gchar *buf;
 232         gchar *file;
 233         buf = g_strdup_printf("%d", cert->port);
 234         file = g_strconcat(get_rc_dir(), G_DIR_SEPARATOR_S,
 235                           "certs", G_DIR_SEPARATOR_S,
 236                           cert->host, ".", buf, ".cert", NULL);
 237         unlink (file);
 238         g_free(buf);
 239         g_free(file);
 240 }
 241
 242 SSLCertificate *ssl_certificate_find (gchar *host, gushort port)
 243 {
 244         return ssl_certificate_find_lookup (host, port, TRUE);
 245 }
 246
 247 SSLCertificate *ssl_certificate_find_lookup (gchar *host, gushort port, gboolean lookup)
 248 {
 249         gchar *file;
 250         gchar *buf;
 251         gchar *fqdn_host;
 252         SSLCertificate *cert = NULL;
 253         X509 *tmp_x509;
 254         FILE *fp;
 255
 256         if (lookup)
 257                 fqdn_host = get_fqdn(host);
 258         else
 259                 fqdn_host = g_strdup(host);
 260
 261         buf = g_strdup_printf("%d", port);
 262         file = g_strconcat(get_rc_dir(), G_DIR_SEPARATOR_S,
 263                           "certs", G_DIR_SEPARATOR_S,
 264                           fqdn_host, ".", buf, ".cert", NULL);
 265
 266         g_free(buf);
 267         fp = fopen(file, "rb");
 268         if (fp == NULL) {
 269                 g_free(file);
 270                 g_free(fqdn_host);
 271                 return NULL;
 272         }
 273
 274
 275         if ((tmp_x509 = d2i_X509_fp(fp, 0)) != NULL) {
 276                 cert = ssl_certificate_new_lookup(tmp_x509, fqdn_host, port, lookup);
 277                 X509_free(tmp_x509);
 278         }
 279         fclose(fp);
 280         g_free(file);
 281         g_free(fqdn_host);
 282
 283         return cert;
 284 }
 285
 286 static gboolean ssl_certificate_compare (SSLCertificate *cert_a, SSLCertificate *cert_b)
 287 {
 288         if (cert_a == NULL || cert_b == NULL)
 289                 return FALSE;
 290         else if (!X509_cmp(cert_a->x509_cert, cert_b->x509_cert))
 291                 return TRUE;
 292         else
 293                 return FALSE;
 294 }
 295
 296 static char *ssl_certificate_check_signer (X509 *cert)
 297 {
 298         X509_STORE_CTX store_ctx;
 299         X509_STORE *store;
 300         int ok = 0;
 301         char *cert_file = NULL;
 302         char *err_msg = NULL;
 303
 304         store = X509_STORE_new();
 305         if (store == NULL) {
 306                 printf("Can't create X509_STORE\n");
 307                 return NULL;
 308         }
 309         if (X509_STORE_set_default_paths(store))
 310                 ok++;
 311         if (X509_STORE_load_locations(store, cert_file, NULL))
 312                 ok++;
 313
 314         if (ok == 0) {
 315                 X509_STORE_free (store);
 316                 return g_strdup(_("Can't load X509 default paths"));
 317         }
 318
 319         X509_STORE_CTX_init (&store_ctx, store, cert, NULL);
 320         ok = X509_verify_cert (&store_ctx);
 321
 322         if (ok == 0) {
 323                 err_msg = g_strdup(X509_verify_cert_error_string(
 324                                         X509_STORE_CTX_get_error(&store_ctx)));
 325                 debug_print("Can't check signer: %s\n", err_msg);
 326                 X509_STORE_CTX_cleanup (&store_ctx);
 327                 X509_STORE_free (store);
 328                 return err_msg;
 329
 330         }
 331         X509_STORE_CTX_cleanup (&store_ctx);
 332         X509_STORE_free (store);
 333         return NULL;
 334 }
 335
 336 gboolean ssl_certificate_check (X509 *x509_cert, gchar *host, gushort port)
 337 {
 338         SSLCertificate *current_cert = ssl_certificate_new(x509_cert, host, port);
 339         SSLCertificate *known_cert;
 340
 341         if (current_cert == NULL) {
 342                 debug_print("Buggy certificate !\n");
 343                 return FALSE;
 344         }
 345
 346         known_cert = ssl_certificate_find (host, port);
 347
 348         if (known_cert == NULL) {
 349                 gint val;
 350                 gchar *err_msg, *cur_cert_str, *sig_status;
 351
 352                 sig_status = ssl_certificate_check_signer(x509_cert);
 353
 354                 if (sig_status == NULL && !prefs_common.ssl_ask_unknown_valid) {
 355                         /* trust and accept silently if hostnames match */
 356                         char *buf; /* don't free buf ! */
 357                         if (X509_NAME_get_text_by_NID(X509_get_subject_name(x509_cert),
 358                                        NID_commonName, buf, 100) >= 0)
 359                                 if (!strcmp(buf, current_cert->host)) {
 360                                         g_free(sig_status);
 361                                         ssl_certificate_save(current_cert);
 362                                         ssl_certificate_destroy(current_cert);
 363                                         return TRUE;
 364                                 }
 365                 }
 366
 367                 g_free(sig_status);
 368
 369                 cur_cert_str = ssl_certificate_to_string(current_cert);
 370
 371                 err_msg = g_strdup_printf(_("%s presented an unknown SSL certificate:\n%s"),
 372                                           current_cert->host,
 373                                           cur_cert_str);
 374                 g_free (cur_cert_str);
 375
 376                 if (prefs_common.no_recv_err_panel) {
 377                         log_error(_("%s\n\nMail won't be retrieved on this account until you save the certificate.\n(Uncheck the \"%s\" preference).\n"),
 378                                         err_msg,
 379                                         _("Don't popup error dialog on receive error"));
 380                         g_free(err_msg);
 381                         return FALSE;
 382                 }
 383
 384                 val = alertpanel(_("Warning"),
 385                                err_msg,
 386                                _("Accept and save"), _("Cancel connection"), NULL);
 387                 g_free(err_msg);
 388
 389                 switch (val) {
 390                         case G_ALERTALTERNATE:
 391                                 ssl_certificate_destroy(current_cert);
 392                                 return FALSE;
 393                         default:
 394                                 ssl_certificate_save(current_cert);
 395                                 ssl_certificate_destroy(current_cert);
 396                                 return TRUE;
 397                 }
 398         }
 399         else if (!ssl_certificate_compare (current_cert, known_cert)) {
 400                 gint val;
 401                 gchar *err_msg, *known_cert_str, *cur_cert_str;
 402
 403                 known_cert_str = ssl_certificate_to_string(known_cert);
 404                 cur_cert_str = ssl_certificate_to_string(current_cert);
 405                 err_msg = g_strdup_printf(_("%s's SSL certificate changed !\nWe have saved this one:\n%s\n\nIt is now:\n%s\n\nThis could mean the server answering is not the known one."),
 406                                           current_cert->host,
 407                                           known_cert_str,
 408                                           cur_cert_str);
 409                 g_free (cur_cert_str);
 410                 g_free (known_cert_str);
 411
 412                 if (prefs_common.no_recv_err_panel) {
 413                         log_error(_("%s\n\nMail won't be retrieved on this account until you save the certificate.\n(Uncheck the \"%s\" preference).\n"),
 414                                         err_msg,
 415                                         _("Don't popup error dialog on receive error"));
 416                         g_free(err_msg);
 417                         return FALSE;
 418                 }
 419
 420                 val = alertpanel(_("Warning"),
 421                                err_msg,
 422                                _("Accept and save"), _("Cancel connection"), NULL);
 423                 g_free(err_msg);
 424
 425                 switch (val) {
 426                         case G_ALERTALTERNATE:
 427                                 ssl_certificate_destroy(current_cert);
 428                                 ssl_certificate_destroy(known_cert);
 429                                 return FALSE;
 430                         default:
 431                                 ssl_certificate_save(current_cert);
 432                                 ssl_certificate_destroy(current_cert);
 433                                 ssl_certificate_destroy(known_cert);
 434                                 return TRUE;
 435                 }
 436         }
 437
 438         ssl_certificate_destroy(current_cert);
 439         ssl_certificate_destroy(known_cert);
 440         return TRUE;
 441 }
 442
 443 #endif /* USE_SSL */