src/common/ssl_certificate.c

   1 /*
   2  * Claws Mail -- a GTK+ based, lightweight, and fast e-mail client
   3  * Copyright (C) 1999-2007 Colin Leroy <colin@colino.net>
   4  * and the Claws Mail team
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  19  */
  20
  21 #ifdef HAVE_CONFIG_H
  22 #  include "config.h"
  23 #endif
  24
  25 #if USE_OPENSSL
  26
  27 #include <openssl/ssl.h>
  28 #include <glib.h>
  29 #include <glib/gi18n.h>
  30
  31 #include "ssl_certificate.h"
  32 #include "utils.h"
  33 #include "log.h"
  34 #include "socket.h"
  35 #include "hooks.h"
  36
  37 static GHashTable *warned_expired = NULL;
  38
  39 gboolean prefs_common_unsafe_ssl_certs(void);
  40
  41 static gchar *get_certificate_path(const gchar *host, const gchar *port, const gchar *fp)
  42 {
  43         if (fp != NULL && prefs_common_unsafe_ssl_certs())
  44                 return g_strconcat(get_rc_dir(), G_DIR_SEPARATOR_S,
  45                           "certs", G_DIR_SEPARATOR_S,
  46                           host, ".", port, ".", fp, ".cert", NULL);
  47         else
  48                 return g_strconcat(get_rc_dir(), G_DIR_SEPARATOR_S,
  49                           "certs", G_DIR_SEPARATOR_S,
  50                           host, ".", port, ".cert", NULL);
  51 }
  52
  53 static SSLCertificate *ssl_certificate_new_lookup(X509 *x509_cert, gchar *host, gushort port, gboolean lookup);
  54
  55 /* from Courier */
  56 time_t asn1toTime(ASN1_TIME *asn1Time)
  57 {
  58         struct tm tm;
  59         int offset;
  60
  61         if (asn1Time == NULL || asn1Time->length < 13)
  62                 return 0;
  63
  64         memset(&tm, 0, sizeof(tm));
  65
  66 #define N2(n)   ((asn1Time->data[n]-'0')*10 + asn1Time->data[(n)+1]-'0')
  67
  68 #define CPY(f,n) (tm.f=N2(n))
  69
  70         CPY(tm_year,0);
  71
  72         if(tm.tm_year < 50)
  73                 tm.tm_year += 100; /* Sux */
  74
  75         CPY(tm_mon, 2);
  76         --tm.tm_mon;
  77         CPY(tm_mday, 4);
  78         CPY(tm_hour, 6);
  79         CPY(tm_min, 8);
  80         CPY(tm_sec, 10);
  81
  82         offset=0;
  83
  84         if (asn1Time->data[12] != 'Z')
  85         {
  86                 if (asn1Time->length < 17)
  87                         return 0;
  88
  89                 offset=N2(13)*3600+N2(15)*60;
  90
  91                 if (asn1Time->data[12] == '-')
  92                         offset= -offset;
  93         }
  94
  95 #undef N2
  96 #undef CPY
  97
  98         return mktime(&tm)-offset;
  99 }
 100
 101 static char * get_fqdn(char *host)
 102 {
 103         struct hostent *hp;
 104
 105         if (host == NULL || strlen(host) == 0)
 106                 return g_strdup("");
 107
 108         hp = my_gethostbyname(host);
 109         if (hp == NULL)
 110                 return g_strdup(host); /*caller should free*/
 111         else
 112                 return g_strdup(hp->h_name);
 113 }
 114
 115 char * readable_fingerprint(unsigned char *src, int len)
 116 {
 117         int i=0;
 118         char * ret;
 119
 120         if (src == NULL)
 121                 return NULL;
 122         ret = g_strdup("");
 123         while (i < len) {
 124                 char *tmp2;
 125                 if(i>0)
 126                         tmp2 = g_strdup_printf("%s:%02X", ret, src[i]);
 127                 else
 128                         tmp2 = g_strdup_printf("%02X", src[i]);
 129                 g_free(ret);
 130                 ret = g_strdup(tmp2);
 131                 g_free(tmp2);
 132                 i++;
 133         }
 134         return ret;
 135 }
 136
 137 static SSLCertificate *ssl_certificate_new_lookup(X509 *x509_cert, gchar *host, gushort port, gboolean lookup)
 138 {
 139         SSLCertificate *cert = g_new0(SSLCertificate, 1);
 140         unsigned int n;
 141         unsigned char md[EVP_MAX_MD_SIZE];
 142
 143         if (host == NULL || x509_cert == NULL) {
 144                 ssl_certificate_destroy(cert);
 145                 return NULL;
 146         }
 147         cert->x509_cert = X509_dup(x509_cert);
 148         if (lookup)
 149                 cert->host = get_fqdn(host);
 150         else
 151                 cert->host = g_strdup(host);
 152         cert->port = port;
 153
 154         /* fingerprint */
 155         X509_digest(cert->x509_cert, EVP_md5(), md, &n);
 156         cert->fingerprint = readable_fingerprint(md, (int)n);
 157
 158         return cert;
 159 }
 160
 161 static void ssl_certificate_save (SSLCertificate *cert)
 162 {
 163         gchar *file, *port;
 164         FILE *fp;
 165
 166         file = g_strconcat(get_rc_dir(), G_DIR_SEPARATOR_S,
 167                           "certs", G_DIR_SEPARATOR_S, NULL);
 168
 169         if (!is_dir_exist(file))
 170                 make_dir_hier(file);
 171         g_free(file);
 172
 173         port = g_strdup_printf("%d", cert->port);
 174         file = get_certificate_path(cert->host, port, cert->fingerprint);
 175
 176         g_free(port);
 177         fp = g_fopen(file, "wb");
 178         if (fp == NULL) {
 179                 g_free(file);
 180                 debug_print("Can't save certificate !\n");
 181                 return;
 182         }
 183         i2d_X509_fp(fp, cert->x509_cert);
 184         g_free(file);
 185         fclose(fp);
 186
 187 }
 188
 189 char* ssl_certificate_to_string(SSLCertificate *cert)
 190 {
 191         char *ret, buf[100];
 192         char *issuer_commonname, *issuer_location, *issuer_organization;
 193         char *subject_commonname, *subject_location, *subject_organization;
 194         char *fingerprint, *sig_status;
 195         unsigned int n;
 196         unsigned char md[EVP_MAX_MD_SIZE];
 197
 198         /* issuer */
 199         if (X509_NAME_get_text_by_NID(X509_get_issuer_name(cert->x509_cert),
 200                                        NID_commonName, buf, 100) >= 0)
 201                 issuer_commonname = g_strdup(buf);
 202         else
 203                 issuer_commonname = g_strdup(_("<not in certificate>"));
 204         if (X509_NAME_get_text_by_NID(X509_get_issuer_name(cert->x509_cert),
 205                                        NID_localityName, buf, 100) >= 0) {
 206                 issuer_location = g_strdup(buf);
 207                 if (X509_NAME_get_text_by_NID(X509_get_issuer_name(cert->x509_cert),
 208                                        NID_countryName, buf, 100) >= 0)
 209                         issuer_location = g_strconcat(issuer_location,", ",buf, NULL);
 210         } else if (X509_NAME_get_text_by_NID(X509_get_issuer_name(cert->x509_cert),
 211                                        NID_countryName, buf, 100) >= 0)
 212                 issuer_location = g_strdup(buf);
 213         else
 214                 issuer_location = g_strdup(_("<not in certificate>"));
 215
 216         if (X509_NAME_get_text_by_NID(X509_get_issuer_name(cert->x509_cert),
 217                                        NID_organizationName, buf, 100) >= 0)
 218                 issuer_organization = g_strdup(buf);
 219         else
 220                 issuer_organization = g_strdup(_("<not in certificate>"));
 221
 222         /* subject */
 223         if (X509_NAME_get_text_by_NID(X509_get_subject_name(cert->x509_cert),
 224                                        NID_commonName, buf, 100) >= 0)
 225                 subject_commonname = g_strdup(buf);
 226         else
 227                 subject_commonname = g_strdup(_("<not in certificate>"));
 228         if (X509_NAME_get_text_by_NID(X509_get_subject_name(cert->x509_cert),
 229                                        NID_localityName, buf, 100) >= 0) {
 230                 subject_location = g_strdup(buf);
 231                 if (X509_NAME_get_text_by_NID(X509_get_subject_name(cert->x509_cert),
 232                                        NID_countryName, buf, 100) >= 0)
 233                         subject_location = g_strconcat(subject_location,", ",buf, NULL);
 234         } else if (X509_NAME_get_text_by_NID(X509_get_subject_name(cert->x509_cert),
 235                                        NID_countryName, buf, 100) >= 0)
 236                 subject_location = g_strdup(buf);
 237         else
 238                 subject_location = g_strdup(_("<not in certificate>"));
 239
 240         if (X509_NAME_get_text_by_NID(X509_get_subject_name(cert->x509_cert),
 241                                        NID_organizationName, buf, 100) >= 0)
 242                 subject_organization = g_strdup(buf);
 243         else
 244                 subject_organization = g_strdup(_("<not in certificate>"));
 245
 246         /* fingerprint */
 247         X509_digest(cert->x509_cert, EVP_md5(), md, &n);
 248         fingerprint = readable_fingerprint(md, (int)n);
 249
 250         /* signature */
 251         sig_status = ssl_certificate_check_signer(cert->x509_cert);
 252
 253         ret = g_strdup_printf(_("  Owner: %s (%s) in %s\n  Signed by: %s (%s) in %s\n  Fingerprint: %s\n  Signature status: %s"),
 254                                 subject_commonname, subject_organization, subject_location,
 255                                 issuer_commonname, issuer_organization, issuer_location,
 256                                 fingerprint,
 257                                 (sig_status==NULL ? "correct":sig_status));
 258
 259         g_free(issuer_commonname);
 260         g_free(issuer_location);
 261         g_free(issuer_organization);
 262         g_free(subject_commonname);
 263         g_free(subject_location);
 264         g_free(subject_organization);
 265         g_free(fingerprint);
 266         g_free(sig_status);
 267         return ret;
 268 }
 269
 270 void ssl_certificate_destroy(SSLCertificate *cert)
 271 {
 272         if (cert == NULL)
 273                 return;
 274
 275         if (cert->x509_cert)
 276                 X509_free(cert->x509_cert);
 277         g_free(cert->host);
 278         g_free(cert->fingerprint);
 279         g_free(cert);
 280         cert = NULL;
 281 }
 282
 283 void ssl_certificate_delete_from_disk(SSLCertificate *cert)
 284 {
 285         gchar *buf;
 286         gchar *file;
 287         buf = g_strdup_printf("%d", cert->port);
 288         file = get_certificate_path(cert->host, buf, cert->fingerprint);
 289         g_unlink (file);
 290         g_free(file);
 291         g_free(buf);
 292 }
 293
 294 SSLCertificate *ssl_certificate_find (gchar *host, gushort port, const gchar *fingerprint)
 295 {
 296         return ssl_certificate_find_lookup (host, port, fingerprint, TRUE);
 297 }
 298
 299 SSLCertificate *ssl_certificate_find_lookup (gchar *host, gushort port, const gchar *fingerprint, gboolean lookup)
 300 {
 301         gchar *file = NULL;
 302         gchar *buf;
 303         gchar *fqdn_host;
 304         SSLCertificate *cert = NULL;
 305         X509 *tmp_x509;
 306         FILE *fp = NULL;
 307         gboolean must_rename = FALSE;
 308
 309         if (lookup)
 310                 fqdn_host = get_fqdn(host);
 311         else
 312                 fqdn_host = g_strdup(host);
 313
 314         buf = g_strdup_printf("%d", port);
 315
 316         if (fingerprint != NULL) {
 317                 file = get_certificate_path(fqdn_host, buf, fingerprint);
 318                 fp = g_fopen(file, "rb");
 319         }
 320         if (fp == NULL) {
 321                 /* see if we have the old one */
 322                 g_free(file);
 323                 file = get_certificate_path(fqdn_host, buf, NULL);
 324                 fp = g_fopen(file, "rb");
 325
 326                 if (fp)
 327                         must_rename = (fingerprint != NULL);
 328         }
 329         if (fp == NULL) {
 330                 g_free(file);
 331                 g_free(fqdn_host);
 332                 g_free(buf);
 333                 return NULL;
 334         }
 335
 336         if ((tmp_x509 = d2i_X509_fp(fp, 0)) != NULL) {
 337                 cert = ssl_certificate_new_lookup(tmp_x509, fqdn_host, port, lookup);
 338                 X509_free(tmp_x509);
 339         }
 340         fclose(fp);
 341         g_free(file);
 342
 343         if (must_rename) {
 344                 gchar *old = get_certificate_path(fqdn_host, buf, NULL);
 345                 gchar *new = get_certificate_path(fqdn_host, buf, fingerprint);
 346                 if (strcmp(old, new))
 347                         move_file(old, new, TRUE);
 348                 g_free(old);
 349                 g_free(new);
 350         }
 351         g_free(buf);
 352         g_free(fqdn_host);
 353
 354         return cert;
 355 }
 356
 357 static gboolean ssl_certificate_compare (SSLCertificate *cert_a, SSLCertificate *cert_b)
 358 {
 359         if (cert_a == NULL || cert_b == NULL)
 360                 return FALSE;
 361         else if (!X509_cmp(cert_a->x509_cert, cert_b->x509_cert))
 362                 return TRUE;
 363         else
 364                 return FALSE;
 365 }
 366
 367 char *ssl_certificate_check_signer (X509 *cert)
 368 {
 369         X509_STORE_CTX store_ctx;
 370         X509_STORE *store;
 371         char *err_msg = NULL;
 372
 373         store = X509_STORE_new();
 374         if (store == NULL) {
 375                 printf("Can't create X509_STORE\n");
 376                 return NULL;
 377         }
 378         if (!X509_STORE_set_default_paths(store)) {
 379                 X509_STORE_free (store);
 380                 return g_strdup(_("Couldn't load X509 default paths"));
 381         }
 382
 383         X509_STORE_CTX_init (&store_ctx, store, cert, NULL);
 384
 385         if(!X509_verify_cert (&store_ctx)) {
 386                 err_msg = g_strdup(X509_verify_cert_error_string(
 387                                         X509_STORE_CTX_get_error(&store_ctx)));
 388                 debug_print("Can't check signer: %s\n", err_msg);
 389                 X509_STORE_CTX_cleanup (&store_ctx);
 390                 X509_STORE_free (store);
 391                 return err_msg;
 392
 393         }
 394         X509_STORE_CTX_cleanup (&store_ctx);
 395         X509_STORE_free (store);
 396         return NULL;
 397 }
 398
 399 gboolean ssl_certificate_check (X509 *x509_cert, gchar *fqdn, gchar *host, gushort port)
 400 {
 401         SSLCertificate *current_cert = NULL;
 402         SSLCertificate *known_cert;
 403         SSLCertHookData cert_hook_data;
 404         gchar *fqdn_host = NULL;
 405         gchar *fingerprint;
 406         unsigned int n;
 407         unsigned char md[EVP_MAX_MD_SIZE];
 408
 409         if (fqdn)
 410                 fqdn_host = g_strdup(fqdn);
 411         else if (host)
 412                 fqdn_host = get_fqdn(host);
 413         else {
 414                 g_warning("no host!\n");
 415                 return FALSE;
 416         }
 417
 418         current_cert = ssl_certificate_new_lookup(x509_cert, fqdn_host, port, FALSE);
 419
 420         if (current_cert == NULL) {
 421                 debug_print("Buggy certificate !\n");
 422                 g_free(fqdn_host);
 423                 return FALSE;
 424         }
 425
 426         /* fingerprint */
 427         X509_digest(x509_cert, EVP_md5(), md, &n);
 428         fingerprint = readable_fingerprint(md, (int)n);
 429
 430         known_cert = ssl_certificate_find_lookup (fqdn_host, port, fingerprint, FALSE);
 431
 432         g_free(fingerprint);
 433         g_free(fqdn_host);
 434
 435         if (known_cert == NULL) {
 436                 cert_hook_data.cert = current_cert;
 437                 cert_hook_data.old_cert = NULL;
 438                 cert_hook_data.expired = FALSE;
 439                 cert_hook_data.accept = FALSE;
 440
 441                 hooks_invoke(SSLCERT_ASK_HOOKLIST, &cert_hook_data);
 442
 443                 if (!cert_hook_data.accept) {
 444                         ssl_certificate_destroy(current_cert);
 445                         return FALSE;
 446                 } else {
 447                         ssl_certificate_save(current_cert);
 448                         ssl_certificate_destroy(current_cert);
 449                         return TRUE;
 450                 }
 451         } else if (!ssl_certificate_compare (current_cert, known_cert)) {
 452                 cert_hook_data.cert = current_cert;
 453                 cert_hook_data.old_cert = known_cert;
 454                 cert_hook_data.expired = FALSE;
 455                 cert_hook_data.accept = FALSE;
 456
 457                 hooks_invoke(SSLCERT_ASK_HOOKLIST, &cert_hook_data);
 458
 459                 if (!cert_hook_data.accept) {
 460                         ssl_certificate_destroy(current_cert);
 461                         ssl_certificate_destroy(known_cert);
 462                         return FALSE;
 463                 } else {
 464                         ssl_certificate_save(current_cert);
 465                         ssl_certificate_destroy(current_cert);
 466                         ssl_certificate_destroy(known_cert);
 467                         return TRUE;
 468                 }
 469         } else if (asn1toTime(X509_get_notAfter(current_cert->x509_cert)) < time(NULL)) {
 470                 gchar *tmp = g_strdup_printf("%s:%d", current_cert->host, current_cert->port);
 471
 472                 if (warned_expired == NULL)
 473                         warned_expired = g_hash_table_new(g_str_hash, g_str_equal);
 474
 475                 if (g_hash_table_lookup(warned_expired, tmp)) {
 476                         g_free(tmp);
 477                         ssl_certificate_destroy(current_cert);
 478                         ssl_certificate_destroy(known_cert);
 479                         return TRUE;
 480                 }
 481
 482                 cert_hook_data.cert = current_cert;
 483                 cert_hook_data.old_cert = NULL;
 484                 cert_hook_data.expired = TRUE;
 485                 cert_hook_data.accept = FALSE;
 486
 487                 hooks_invoke(SSLCERT_ASK_HOOKLIST, &cert_hook_data);
 488
 489                 if (!cert_hook_data.accept) {
 490                         g_free(tmp);
 491                         ssl_certificate_destroy(current_cert);
 492                         ssl_certificate_destroy(known_cert);
 493                         return FALSE;
 494                 } else {
 495                         g_hash_table_insert(warned_expired, tmp, GINT_TO_POINTER(1));
 496                         ssl_certificate_destroy(current_cert);
 497                         ssl_certificate_destroy(known_cert);
 498                         return TRUE;
 499                 }
 500         }
 501
 502         ssl_certificate_destroy(current_cert);
 503         ssl_certificate_destroy(known_cert);
 504         return TRUE;
 505 }
 506
 507 #endif /* USE_OPENSSL */