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