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/* packet-cms.c
* Routines for RFC2630 Cryptographic Message Syntax packet dissection
* Ronnie Sahlberg 2004
*
* $Id$
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <glib.h>
#include <epan/packet.h>
#include <epan/conversation.h>
#include <stdio.h>
#include <string.h>
#include "packet-ber.h"
#include "packet-cms.h"
#include "packet-x509af.h"
#include "packet-x509if.h"
#include <epan/sha1.h>
#include <epan/crypt-md5.h>
#define PNAME "Cryptographic Message Syntax"
#define PSNAME "CMS"
#define PFNAME "cms"
/* Initialize the protocol and registered fields */
int proto_cms = -1;
static int hf_cms_ci_contentType = -1;
#include "packet-cms-hf.c"
/* Initialize the subtree pointers */
#include "packet-cms-ett.c"
static int dissect_cms_OCTET_STRING(gboolean implicit_tag _U_, tvbuff_t *tvb, int offset, packet_info *pinfo _U_, proto_tree *tree, int hf_index _U_) ; /* XXX kill a compiler warning until asn2eth stops generating these silly wrappers */
static const char *object_identifier_id;
static tvbuff_t *content_tvb = NULL;
static proto_tree *top_tree=NULL;
#define HASH_SHA1 "1.3.14.3.2.26"
#define SHA1_BUFFER_SIZE 20
#define HASH_MD5 "1.2.840.113549.2.5"
#define MD5_BUFFER_SIZE 16
/* SHA-2 variants */
#define HASH_SHA224 "2.16.840.1.101.3.4.2.4"
#define SHA224_BUFFER_SIZE 32 /* actually 28 */
#define HASH_SHA256 "2.16.840.1.101.3.4.2.1"
#define SHA256_BUFFER_SIZE 32
unsigned char digest_buf[MAX(SHA1_BUFFER_SIZE, MD5_BUFFER_SIZE)];
static void
cms_verify_msg_digest(proto_item *pi, tvbuff_t *content, const char *alg, tvbuff_t *tvb, int offset)
{
sha1_context sha1_ctx;
md5_state_t md5_ctx;
int i= 0, buffer_size = 0;
/* we only support two algorithms at the moment - if we do add SHA2
we should add a registration process to use a registration process */
if(strcmp(alg, HASH_SHA1) == 0) {
sha1_starts(&sha1_ctx);
sha1_update(&sha1_ctx, tvb_get_ptr(content, 0, tvb_length(content)),
tvb_length(content));
sha1_finish(&sha1_ctx, digest_buf);
buffer_size = SHA1_BUFFER_SIZE;
} else if(strcmp(alg, HASH_MD5) == 0) {
md5_init(&md5_ctx);
md5_append(&md5_ctx, tvb_get_ptr(content, 0, tvb_length(content)),
tvb_length(content));
md5_finish(&md5_ctx, digest_buf);
buffer_size = MD5_BUFFER_SIZE;
}
if(buffer_size) {
/* compare our computed hash with what we have received */
if(tvb_bytes_exist(tvb, offset, buffer_size) &&
(memcmp(tvb_get_ptr(tvb, offset, buffer_size), digest_buf, buffer_size) != 0)) {
proto_item_append_text(pi, " [incorrect, should be ");
for(i = 0; i < buffer_size; i++)
proto_item_append_text(pi, "%02X", digest_buf[i]);
proto_item_append_text(pi, "]");
}
else
proto_item_append_text(pi, " [correct]");
} else {
proto_item_append_text(pi, " [unable to verify]");
}
}
#include "packet-cms-fn.c"
/*--- proto_register_cms ----------------------------------------------*/
void proto_register_cms(void) {
/* List of fields */
static hf_register_info hf[] = {
{ &hf_cms_ci_contentType,
{ "contentType", "cms.contentInfo.contentType",
FT_OID, BASE_NONE, NULL, 0,
"ContentType", HFILL }},
#include "packet-cms-hfarr.c"
};
/* List of subtrees */
static gint *ett[] = {
#include "packet-cms-ettarr.c"
};
/* Register protocol */
proto_cms = proto_register_protocol(PNAME, PSNAME, PFNAME);
/* Register fields and subtrees */
proto_register_field_array(proto_cms, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
}
/*--- proto_reg_handoff_cms -------------------------------------------*/
void proto_reg_handoff_cms(void) {
#include "packet-cms-dis-tab.c"
}
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