/*
* Copyright 2008-2019 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <openssl/asn1t.h>
#include <openssl/pem.h>
#include <openssl/x509v3.h>
#include <openssl/err.h>
#include <openssl/cms.h>
#include "cms_local.h"
#include "internal/nelem.h"
/*-
* Attribute flags.
* CMS attribute restrictions are discussed in
* - RFC 5652 Section 11.
* ESS attribute restrictions are discussed in
* - RFC 2634 Section 1.3.4 AND
* - RFC 5035 Section 5.4
*/
/* This is a signed attribute */
#define CMS_ATTR_F_SIGNED 0x01
/* This is an unsigned attribute */
#define CMS_ATTR_F_UNSIGNED 0x02
/* Must be present if there are any other attributes of the same type */
#define CMS_ATTR_F_REQUIRED_COND 0x10
/* There can only be one instance of this attribute */
#define CMS_ATTR_F_ONLY_ONE 0x20
/* The Attribute's value must have exactly one entry */
#define CMS_ATTR_F_ONE_ATTR_VALUE 0x40
/* Attributes rules for different attributes */
static const struct {
int nid; /* The attribute id */
int flags;
} cms_attribute_properties[] = {
/* See RFC Section 11 */
{ NID_pkcs9_contentType, CMS_ATTR_F_SIGNED
| CMS_ATTR_F_ONLY_ONE
| CMS_ATTR_F_ONE_ATTR_VALUE
| CMS_ATTR_F_REQUIRED_COND },
{ NID_pkcs9_messageDigest, CMS_ATTR_F_SIGNED
| CMS_ATTR_F_ONLY_ONE
| CMS_ATTR_F_ONE_ATTR_VALUE
| CMS_ATTR_F_REQUIRED_COND },
{ NID_pkcs9_signingTime, CMS_ATTR_F_SIGNED
| CMS_ATTR_F_ONLY_ONE
| CMS_ATTR_F_ONE_ATTR_VALUE },
{ NID_pkcs9_countersignature, CMS_ATTR_F_UNSIGNED },
/* ESS */
{ NID_id_smime_aa_signingCertificate, CMS_ATTR_F_SIGNED
| CMS_ATTR_F_ONLY_ONE
| CMS_ATTR_F_ONE_ATTR_VALUE },
{ NID_id_smime_aa_signingCertificateV2, CMS_ATTR_F_SIGNED
| CMS_ATTR_F_ONLY_ONE
| CMS_ATTR_F_ONE_ATTR_VALUE },
{ NID_id_smime_aa_receiptRequest, CMS_ATTR_F_SIGNED
| CMS_ATTR_F_ONLY_ONE
| CMS_ATTR_F_ONE_ATTR_VALUE }
};
/* CMS SignedData Attribute utilities */
int CMS_signed_get_attr_count(const CMS_SignerInfo *si)
{
return X509at_get_attr_count(si->signedAttrs);
}
int CMS_signed_get_attr_by_NID(const CMS_SignerInfo *si, int nid, int lastpos)
{
return X509at_get_attr_by_NID(si->signedAttrs, nid, lastpos);
}
int CMS_signed_get_attr_by_OBJ(const CMS_SignerInfo *si, const ASN1_OBJECT *obj,
int lastpos)
{
return X509at_get_attr_by_OBJ(si->signedAttrs, obj, lastpos);
}
X509_ATTRIBUTE *CMS_signed_get_attr(const CMS_SignerInfo *si, int loc)
{
return X509at_get_attr(si->signedAttrs, loc);
}
X509_ATTRIBUTE *CMS_signed_delete_attr(CMS_SignerInfo *si, int loc)
{
return X509at_delete_attr(si->signedAttrs, loc);
}
int CMS_signed_add1_attr(CMS_SignerInfo *si, X509_ATTRIBUTE *attr)
{
if (X509at_add1_attr(&si->signedAttrs, attr))
return 1;
return 0;
}
int CMS_signed_add1_attr_by_OBJ(CMS_SignerInfo *si,
const ASN1_OBJECT *obj, int type,
const void *bytes, int len)
{
if (X509at_add1_attr_by_OBJ(&si->signedAttrs, obj, type, bytes, len))
return 1;
return 0;
}
int CMS_signed_add1_attr_by_NID(CMS_SignerInfo *si,
int nid, int type, const void *bytes, int len)
{
if (X509at_add1_attr_by_NID(&si->signedAttrs, nid, type, bytes, len))
return 1;
return 0;
}
int CMS_signed_add1_attr_by_txt(CMS_SignerInfo *si,
const char *attrname, int type,
const void *bytes, int len)
{
if (X509at_add1_attr_by_txt(&si->signedAttrs, attrname, type, bytes, len))
return 1;
return 0;
}
void *CMS_signed_get0_data_by_OBJ(CMS_SignerInfo *si, const ASN1_OBJECT *oid,
int lastpos, int type)
{
return X509at_get0_data_by_OBJ(si->signedAttrs, oid, lastpos, type);
}
int CMS_unsigned_get_attr_count(const CMS_SignerInfo *si)
{
return X509at_get_attr_count(si->unsignedAttrs);
}
int CMS_unsigned_get_attr_by_NID(const CMS_SignerInfo *si, int nid,
int lastpos)
{
return X509at_get_attr_by_NID(si->unsignedAttrs, nid, lastpos);
}
int CMS_unsigned_get_attr_by_OBJ(const CMS_SignerInfo *si,
const ASN1_OBJECT *obj, int lastpos)
{
return X509at_get_attr_by_OBJ(si->unsignedAttrs, obj, lastpos);
}
X509_ATTRIBUTE *CMS_unsigned_get_attr(const CMS_SignerInfo *si, int loc)
{
return X509at_get_attr(si->unsignedAttrs, loc);
}
X509_ATTRIBUTE *CMS_unsigned_delete_attr(CMS_SignerInfo *si, int loc)
{
return X509at_delete_attr(si->unsignedAttrs, loc);
}
int CMS_unsigned_add1_attr(CMS_SignerInfo *si, X509_ATTRIBUTE *attr)
{
if (X509at_add1_attr(&si->unsignedAttrs, attr))
return 1;
return 0;
}
int CMS_unsigned_add1_attr_by_OBJ(CMS_SignerInfo *si,
const ASN1_OBJECT *obj, int type,
const void *bytes, int len)
{
if (X509at_add1_attr_by_OBJ(&si->unsignedAttrs, obj, type, bytes, len))
return 1;
return 0;
}
int CMS_unsigned_add1_attr_by_NID(CMS_SignerInfo *si,
int nid, int type,
const void *bytes, int len)
{
if (X509at_add1_attr_by_NID(&si->unsignedAttrs, nid, type, bytes, len))
return 1;
return 0;
}
int CMS_unsigned_add1_attr_by_txt(CMS_SignerInfo *si,
const char *attrname, int type,
const void *bytes, int len)
{
if (X509at_add1_attr_by_txt(&si->unsignedAttrs, attrname,
type, bytes, len))
return 1;
return 0;
}
void *CMS_unsigned_get0_data_by_OBJ(CMS_SignerInfo *si, ASN1_OBJECT *oid,
int lastpos, int type)
{
return X509at_get0_data_by_OBJ(si->unsignedAttrs, oid, lastpos, type);
}
/*
* Retrieve an attribute by nid from a stack of attributes starting at index
* *lastpos + 1.
* Returns the attribute or NULL if there is no attribute.
* If an attribute was found *lastpos returns the index of the found attribute.
*/
static X509_ATTRIBUTE *cms_attrib_get(int nid,
const STACK_OF(X509_ATTRIBUTE) *attrs,
int *lastpos)
{
X509_ATTRIBUTE *at;
int loc;
loc = X509at_get_attr_by_NID(attrs, nid, *lastpos);
if (loc < 0)
return NULL;
at = X509at_get_attr(attrs, loc);
*lastpos = loc;
return at;
}
static int cms_check_attribute(int nid, int flags, int type,
const STACK_OF(X509_ATTRIBUTE) *attrs,
int have_attrs)
{
int lastpos = -1;
X509_ATTRIBUTE *at = cms_attrib_get(nid, attrs, &lastpos);
if (at != NULL) {
int count = X509_ATTRIBUTE_count(at);
/* Is this attribute allowed? */
if (((flags & type) == 0)
/* check if multiple attributes of the same type are allowed */
|| (((flags & CMS_ATTR_F_ONLY_ONE) != 0)
&& cms_attrib_get(nid, attrs, &lastpos) != NULL)
/* Check if attribute should have exactly one value in its set */
|| (((flags & CMS_ATTR_F_ONE_ATTR_VALUE) != 0)
&& count != 1)
/* There should be at least one value */
|| count == 0)
return 0;
} else {
/* fail if a required attribute is missing */
if (have_attrs
&& ((flags & CMS_ATTR_F_REQUIRED_COND) != 0)
&& (flags & type) != 0)
return 0;
}
return 1;
}
/*
* Check that the signerinfo attributes obey the attribute rules which includes
* the following checks
* - If any signed attributes exist then there must be a Content Type
* and Message Digest attribute in the signed attributes.
* - The countersignature attribute is an optional unsigned attribute only.
* - Content Type, Message Digest, and Signing time attributes are signed
* attributes. Only one instance of each is allowed, with each of these
* attributes containing a single attribute value in its set.
*/
int CMS_si_check_attributes(const CMS_SignerInfo *si)
{
int i;
int have_signed_attrs = (CMS_signed_get_attr_count(si) > 0);
int have_unsigned_attrs = (CMS_unsigned_get_attr_count(si) > 0);
for (i = 0; i < (int)OSSL_NELEM(cms_attribute_properties); ++i) {
int nid = cms_attribute_properties[i].nid;
int flags = cms_attribute_properties[i].flags;
if (!cms_check_attribute(nid, flags, CMS_ATTR_F_SIGNED,
si->signedAttrs, have_signed_attrs)
|| !cms_check_attribute(nid, flags, CMS_ATTR_F_UNSIGNED,
si->unsignedAttrs, have_unsigned_attrs)) {
CMSerr(CMS_F_CMS_SI_CHECK_ATTRIBUTES, CMS_R_ATTRIBUTE_ERROR);
return 0;
}
}
return 1;
}