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/* packet-cms.c
* Routines for RFC5652 Cryptographic Message Syntax packet dissection
* Ronnie Sahlberg 2004
* Stig Bjorlykke 2010
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/oids.h>
#include <epan/asn1.h>
#include <wsutil/wsgcrypt.h>
#include "packet-ber.h"
#include "packet-cms.h"
#include "packet-x509af.h"
#include "packet-x509ce.h"
#include "packet-x509if.h"
#include "packet-x509sat.h"
#include "packet-pkcs12.h"
#define PNAME "Cryptographic Message Syntax"
#define PSNAME "CMS"
#define PFNAME "cms"
void proto_register_cms(void);
void proto_reg_handoff_cms(void);
/* Initialize the protocol and registered fields */
static 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, asn1_ctx_t *actx, proto_tree *tree, int hf_index _U_) ; /* XXX kill a compiler warning until asn2wrs stops generating these silly wrappers */
static const char *object_identifier_id = NULL;
static tvbuff_t *content_tvb = NULL;
static proto_tree *top_tree=NULL;
static proto_tree *cap_tree=NULL;
#define HASH_SHA1 "1.3.14.3.2.26"
#define HASH_MD5 "1.2.840.113549.2.5"
/* 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(HASH_SHA1_LENGTH, HASH_MD5_LENGTH)];
static void
cms_verify_msg_digest(proto_item *pi, tvbuff_t *content, const char *alg, tvbuff_t *tvb, int offset)
{
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) {
gcry_md_hash_buffer(GCRY_MD_SHA1, digest_buf, tvb_get_ptr(content, 0, tvb_captured_length(content)), tvb_captured_length(content));
buffer_size = HASH_SHA1_LENGTH;
} else if(strcmp(alg, HASH_MD5) == 0) {
gcry_md_hash_buffer(GCRY_MD_MD5, digest_buf, tvb_get_ptr(content, 0, tvb_captured_length(content)), tvb_captured_length(content));
buffer_size = HASH_MD5_LENGTH;
}
if(buffer_size) {
/* compare our computed hash with what we have received */
if(tvb_bytes_exist(tvb, offset, buffer_size) &&
(tvb_memeql(tvb, offset, 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,
NULL, 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));
register_ber_syntax_dissector("ContentInfo", proto_cms, dissect_ContentInfo_PDU);
register_ber_syntax_dissector("SignedData", proto_cms, dissect_SignedData_PDU);
register_ber_oid_syntax(".p7s", NULL, "ContentInfo");
register_ber_oid_syntax(".p7m", NULL, "ContentInfo");
register_ber_oid_syntax(".p7c", NULL, "ContentInfo");
}
/*--- proto_reg_handoff_cms -------------------------------------------*/
void proto_reg_handoff_cms(void) {
dissector_handle_t content_info_handle;
#include "packet-cms-dis-tab.c"
/* RFC 3370 [CMS-ASN} section 4.3.1 */
register_ber_oid_dissector("1.2.840.113549.1.9.16.3.6", dissect_ber_oid_NULL_callback, proto_cms, "id-alg-CMS3DESwrap");
oid_add_from_string("id-data","1.2.840.113549.1.7.1");
oid_add_from_string("id-alg-des-cbc","1.3.14.3.2.7");
content_info_handle = create_dissector_handle (dissect_ContentInfo_PDU, proto_cms);
dissector_add_string("media_type", "application/pkcs7-mime", content_info_handle);
dissector_add_string("media_type", "application/pkcs7-signature", content_info_handle);
dissector_add_string("rfc7468.preeb_label", "CMS", content_info_handle);
}
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