asn1/cms/packet-cms-template.c

   1 /* packet-cms.c
   2  * Routines for RFC5652 Cryptographic Message Syntax packet dissection
   3  *   Ronnie Sahlberg 2004
   4  *   Stig Bjorlykke 2010
   5  *
   6  * $Id$
   7  *
   8  * Wireshark - Network traffic analyzer
   9  * By Gerald Combs <gerald@wireshark.org>
  10  * Copyright 1998 Gerald Combs
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  25  */
  26
  27 #include "config.h"
  28
  29 #include <glib.h>
  30
  31 #include <wsutil/sha1.h>
  32 #include <wsutil/md5.h>
  33
  34 #include <epan/packet.h>
  35 #include <epan/oids.h>
  36 #include <epan/asn1.h>
  37
  38 #include <string.h>
  39
  40 #include "packet-ber.h"
  41 #include "packet-cms.h"
  42 #include "packet-x509af.h"
  43 #include "packet-x509ce.h"
  44 #include "packet-x509if.h"
  45 #include "packet-x509sat.h"
  46 #include "packet-pkcs12.h"
  47
  48 #define PNAME  "Cryptographic Message Syntax"
  49 #define PSNAME "CMS"
  50 #define PFNAME "cms"
  51
  52 /* Initialize the protocol and registered fields */
  53 static int proto_cms = -1;
  54 static int hf_cms_ci_contentType = -1;
  55 #include "packet-cms-hf.c"
  56
  57 /* Initialize the subtree pointers */
  58 #include "packet-cms-ett.c"
  59
  60 static int dissect_cms_OCTET_STRING(gboolean implicit_tag _U_, tvbuff_t *tvb, int offset, asn1_ctx_t *actx, proto_tree *tree, int hf_index _U_) ; /* XXX kill a compiler warning until asn2wrs stops generating these silly wrappers */
  61
  62
  63 static const char *object_identifier_id;
  64 static tvbuff_t *content_tvb = NULL;
  65
  66 static proto_tree *top_tree=NULL;
  67 static proto_tree *cap_tree=NULL;
  68
  69 #define HASH_SHA1 "1.3.14.3.2.26"
  70 #define SHA1_BUFFER_SIZE  20
  71
  72 #define HASH_MD5 "1.2.840.113549.2.5"
  73 #define MD5_BUFFER_SIZE  16
  74
  75
  76 /* SHA-2 variants */
  77 #define HASH_SHA224 "2.16.840.1.101.3.4.2.4"
  78 #define SHA224_BUFFER_SIZE  32 /* actually 28 */
  79 #define HASH_SHA256 "2.16.840.1.101.3.4.2.1"
  80 #define SHA256_BUFFER_SIZE  32
  81
  82 unsigned char digest_buf[MAX(SHA1_BUFFER_SIZE, MD5_BUFFER_SIZE)];
  83
  84 static void
  85 cms_verify_msg_digest(proto_item *pi, tvbuff_t *content, const char *alg, tvbuff_t *tvb, int offset)
  86 {
  87   sha1_context sha1_ctx;
  88   md5_state_t md5_ctx;
  89   int i= 0, buffer_size = 0;
  90
  91   /* we only support two algorithms at the moment  - if we do add SHA2
  92      we should add a registration process to use a registration process */
  93
  94   if(strcmp(alg, HASH_SHA1) == 0) {
  95
  96     sha1_starts(&sha1_ctx);
  97
  98     sha1_update(&sha1_ctx, tvb_get_ptr(content, 0, tvb_length(content)),
  99                 tvb_length(content));
 100
 101     sha1_finish(&sha1_ctx, digest_buf);
 102
 103     buffer_size = SHA1_BUFFER_SIZE;
 104
 105   } else if(strcmp(alg, HASH_MD5) == 0) {
 106
 107     md5_init(&md5_ctx);
 108
 109     md5_append(&md5_ctx, tvb_get_ptr(content, 0, tvb_length(content)),
 110                tvb_length(content));
 111
 112     md5_finish(&md5_ctx, digest_buf);
 113
 114     buffer_size = MD5_BUFFER_SIZE;
 115   }
 116
 117   if(buffer_size) {
 118     /* compare our computed hash with what we have received */
 119
 120     if(tvb_bytes_exist(tvb, offset, buffer_size) &&
 121        (tvb_memeql(tvb, offset, digest_buf, buffer_size) != 0)) {
 122       proto_item_append_text(pi, " [incorrect, should be ");
 123       for(i = 0; i < buffer_size; i++)
 124         proto_item_append_text(pi, "%02X", digest_buf[i]);
 125
 126       proto_item_append_text(pi, "]");
 127     }
 128     else
 129       proto_item_append_text(pi, " [correct]");
 130   } else {
 131     proto_item_append_text(pi, " [unable to verify]");
 132   }
 133
 134 }
 135
 136 #include "packet-cms-fn.c"
 137
 138 /*--- proto_register_cms ----------------------------------------------*/
 139 void proto_register_cms(void) {
 140
 141   /* List of fields */
 142   static hf_register_info hf[] = {
 143     { &hf_cms_ci_contentType,
 144       { "contentType", "cms.contentInfo.contentType",
 145         FT_OID, BASE_NONE, NULL, 0,
 146         NULL, HFILL }},
 147 #include "packet-cms-hfarr.c"
 148   };
 149
 150   /* List of subtrees */
 151   static gint *ett[] = {
 152 #include "packet-cms-ettarr.c"
 153   };
 154
 155   /* Register protocol */
 156   proto_cms = proto_register_protocol(PNAME, PSNAME, PFNAME);
 157
 158   /* Register fields and subtrees */
 159   proto_register_field_array(proto_cms, hf, array_length(hf));
 160   proto_register_subtree_array(ett, array_length(ett));
 161
 162   register_ber_syntax_dissector("ContentInfo", proto_cms, dissect_ContentInfo_PDU);
 163   register_ber_syntax_dissector("SignedData", proto_cms, dissect_SignedData_PDU);
 164   register_ber_oid_syntax(".p7s", NULL, "ContentInfo");
 165   register_ber_oid_syntax(".p7m", NULL, "ContentInfo");
 166   register_ber_oid_syntax(".p7c", NULL, "ContentInfo");
 167
 168
 169 }
 170
 171
 172 /*--- proto_reg_handoff_cms -------------------------------------------*/
 173 void proto_reg_handoff_cms(void) {
 174 #include "packet-cms-dis-tab.c"
 175
 176   oid_add_from_string("id-data","1.2.840.113549.1.7.1");
 177   oid_add_from_string("id-alg-des-ede3-cbc","1.2.840.113549.3.7");
 178   oid_add_from_string("id-alg-des-cbc","1.3.14.3.2.7");
 179
 180 }
 181