signer_info.c

// SPDX-License-Identifier: GPLv2
/*
 * signer_info.c - implement the authenticode signer_info structure
 * Copyright Peter Jones <pjones@redhat.com>
 * Copyright Red Hat, Inc.
 */
#include "pesign.h"

#include <string.h>
#include <syslog.h>
#include <time.h>
#include <unistd.h>

#include <prerror.h>
#include <cms.h>
#include <cryptohi.h>
#include <keyhi.h>
#include <pk11pub.h>

SEC_ASN1Template AttributeTemplate[] = {
	{
	.kind = SEC_ASN1_SEQUENCE,
	.offset = 0,
	.sub = NULL,
	.size = sizeof (Attribute)
	},
	{
	.kind = SEC_ASN1_OBJECT_ID,
	.offset = offsetof(Attribute, attrType),
	.sub = &SEC_ObjectIDTemplate,
	.size = sizeof (SECItem)
	},
	{
	.kind = SEC_ASN1_SET_OF,
	.offset = offsetof(Attribute, attrValues),
	.sub = &SEC_AnyTemplate,
	.size = sizeof (SECItem **)
	},
	{ 0, }
};

SEC_ASN1Template AttributeSetTemplate[] = {
	{
	.kind = SEC_ASN1_SET_OF,
	.offset = 0,
	.sub = AttributeTemplate,
	.size = 0
	},
};

SEC_ASN1Template SignedAttributesTemplate[] = {
	{
	.kind = SEC_ASN1_CONTEXT_SPECIFIC | 0,
	.offset = 0,
	.sub = &AttributeSetTemplate,
	.size = 0
	}
};

int
generate_signed_attributes(cms_context *cms, SECItem *sattrs)
{
	Attribute *attrs[5];
	memset(attrs, '\0', sizeof (attrs));

	SECItem encoded;
	SECOidTag tag;
	SECOidData *oid;

	/* build the first attribute, which says we have no S/MIME
	 * capabilities whatsoever */
	attrs[0] = PORT_ArenaZAlloc(cms->arena, sizeof (Attribute));
	if (!attrs[0])
		goto err;

	oid = SECOID_FindOIDByTag(SEC_OID_PKCS9_SMIME_CAPABILITIES);
	attrs[0]->attrType = oid->oid;

	SECItem *smime_caps[2] = { NULL, NULL};
	if (generate_empty_sequence(cms, &encoded) < 0)
		goto err;
	smime_caps[0] = SECITEM_ArenaDupItem(cms->arena, &encoded);
	attrs[0]->attrValues = smime_caps;

	/* build the second attribute, which says that this is
	 * a PKCS9 content blob thingy */
	attrs[1] = PORT_ArenaZAlloc(cms->arena, sizeof (Attribute));
	if (!attrs[1])
		goto err;

	oid = SECOID_FindOIDByTag(SEC_OID_PKCS9_CONTENT_TYPE);
	attrs[1]->attrType = oid->oid;

	SECItem *content_types[2] = { NULL, NULL };
	tag = find_ms_oid_tag(SPC_INDIRECT_DATA_OBJID);
	if (tag == SEC_OID_UNKNOWN)
		goto err;
	if (generate_object_id(cms, &encoded, tag) < 0)
		goto err;
	content_types[0] = SECITEM_ArenaDupItem(cms->arena, &encoded);
	if (!content_types[0])
		goto err;
	attrs[1]->attrValues = content_types;

	/* build the third attribute.  This is our signing time. */
	attrs[2] = PORT_ArenaZAlloc(cms->arena, sizeof (Attribute));
	if (!attrs[2])
		goto err;

	oid = SECOID_FindOIDByTag(SEC_OID_PKCS9_SIGNING_TIME);
	attrs[2]->attrType = oid->oid;

	SECItem *signing_time[2] = { NULL, NULL };
	if (generate_time(cms, &encoded, time(NULL)) < 0)
		goto err;
	signing_time[0] = SECITEM_ArenaDupItem(cms->arena, &encoded);
	if (!signing_time[0])
		goto err;
	attrs[2]->attrValues = signing_time;

	/* build the fourth attribute, which is our PKCS9 message
	 * digest (which is a SHA-whatever selected and generated elsewhere */
	attrs[3] = PORT_ArenaZAlloc(cms->arena, sizeof (Attribute));
	if (!attrs[3])
		goto err;

	oid = SECOID_FindOIDByTag(SEC_OID_PKCS9_MESSAGE_DIGEST);
	attrs[3]->attrType = oid->oid;

	SECItem *digest_values[2] = { NULL, NULL };
	if (generate_octet_string(cms, &encoded, cms->ci_digest) < 0)
		goto err;
	digest_values[0] = SECITEM_ArenaDupItem(cms->arena, &encoded);
	if (!digest_values[0])
		goto err;
	attrs[3]->attrValues = digest_values;

	Attribute **attrtmp = attrs;
	if (SEC_ASN1EncodeItem(cms->arena, sattrs, &attrtmp,
				AttributeSetTemplate) == NULL)
		goto err;
	return 0;
err:
	return -1;
}

static int
sign_blob(cms_context *cms, SECItem *sigitem, SECItem *sign_content)
{
	sign_content = SECITEM_ArenaDupItem(cms->arena, sign_content);
	if (!sign_content)
		return -1;

	if (content_is_empty(sign_content->data, sign_content->len)) {
		cms->log(cms, LOG_ERR, "not signing empty digest");
		return -1;
	}

	SECOidData *oid = SECOID_FindOIDByTag(digest_get_signature_oid(cms));
	if (!oid)
		goto err;

	PK11_SetPasswordFunc(cms->func ? cms->func : SECU_GetModulePassword);
	SECKEYPrivateKey *privkey = PK11_FindKeyByAnyCert(cms->cert, cms);
	if (!privkey) {
		cms->log(cms, LOG_ERR, "could not get private key: %s",
			PORT_ErrorToString(PORT_GetError()));
		goto err;
	}

	SECItem *signature, tmp;
	memset (&tmp, '\0', sizeof (tmp));

	SECStatus status;
	status = SEC_SignData(&tmp, sign_content->data, sign_content->len,
			privkey, oid->offset);
	SECKEY_DestroyPrivateKey(privkey);
	privkey = NULL;

	if (status != SECSuccess) {
		cms->log(cms, LOG_ERR, "error signing data: %s",
			PORT_ErrorToString(PORT_GetError()));
		PORT_Free(tmp.data);
		return -1;
	}

	/* SEC_SignData awesomely allocates a SECItem and its contents for
	 * the signature, meaning they're not in our nss arena.  Fix it. */
	signature = SECITEM_AllocItem(cms->arena, NULL, tmp.len);
	if (!signature) {
		cms->log(cms, LOG_ERR, "error signing data: %s",
			PORT_ErrorToString(PORT_GetError()));
		return -1;
	}
	memcpy(signature->data, tmp.data, tmp.len);
	PORT_Free(tmp.data);

	if (status != SECSuccess) {
		cms->log(cms, LOG_ERR, "error signing data: %s",
			PORT_ErrorToString(PORT_GetError()));
		return -1;
	}
	memcpy(sigitem, signature, sizeof(*sigitem));

	//SECITEM_FreeItem(sign_content, PR_TRUE);
	return 0;
err:
	//SECITEM_FreeItem(sign_content, PR_TRUE);
	return -1;
}

static int
generate_unsigned_attributes(cms_context *cms, SECItem *uattrs)
{
	Attribute *attrs[1];
	memset(attrs, '\0', sizeof (attrs));

	Attribute **attrtmp = attrs;
	if (SEC_ASN1EncodeItem(cms->arena, uattrs, &attrtmp,
				AttributeSetTemplate) == NULL)
		goto err;
	return 0;
err:
	return -1;
}

SEC_ASN1Template IssuerAndSerialNumberTemplate[] = {
	{
	.kind = SEC_ASN1_SEQUENCE,
	.offset = 0,
	.sub = NULL,
	.size = sizeof (IssuerAndSerialNumber)
	},
	{
	.kind = SEC_ASN1_ANY,
	.offset = offsetof(IssuerAndSerialNumber, issuer),
	.sub = &SEC_AnyTemplate,
	.size = sizeof (SECItem)
	},
	{
	.kind = SEC_ASN1_INTEGER,
	.offset = offsetof(IssuerAndSerialNumber, serial),
	.sub = &SEC_IntegerTemplate,
	.size = sizeof (SECItem)
	},
	{ 0, }
};

SEC_ASN1Template SignerIdentifierTemplate[] = {
	/* we don't /really/ ever need signerType ==
	 * signerTypeSubjectKeyIdentifier */
#if 0
	{
	.kind = SEC_ASN1_CHOICE,
	.offset = offsetof(SignerIdentifier, signerType),
	.sub = NULL,
	.size = sizeof (SignerIdentifier)
	},
#endif
	{
	.kind = SEC_ASN1_INLINE,
	.offset = offsetof(SignerIdentifier, signerValue.iasn),
	.sub = &IssuerAndSerialNumberTemplate,
	.size = signerTypeIssuerAndSerialNumber,
	},
#if 0
	{
	.kind = SEC_ASN1_CONTEXT_SPECIFIC | 0 |
		SEC_ASN1_EXPLICIT |
		SEC_ASN1_CONSTRUCTED,
	.offset = offsetof(SignerIdentifier, signerValue.subjectKeyID),
	.sub = &SEC_OctetStringTemplate,
	.size = signerTypeSubjectKeyIdentifier,
	},
#endif
	{ 0, }
};

SEC_ASN1Template SpcSignerInfoTemplate[] = {
	{
	.kind = SEC_ASN1_SEQUENCE,
	.offset = 0,
	.sub = NULL,
	.size = 0,
	},
	{
	.kind = SEC_ASN1_INTEGER,
	.offset = offsetof(SpcSignerInfo, CMSVersion),
	.sub = &SEC_IntegerTemplate,
	.size = sizeof (SECItem),
	},
	{
	.kind = SEC_ASN1_INLINE,
	.offset = offsetof(SpcSignerInfo, sid),
	.sub = &SignerIdentifierTemplate,
	.size = sizeof (SignerIdentifier),
	},
	{
	.kind = SEC_ASN1_INLINE,
	.offset = offsetof(SpcSignerInfo, digestAlgorithm),
	.sub = &SECOID_AlgorithmIDTemplate,
	.size = sizeof (SECAlgorithmID)
	},
	{
	.kind = SEC_ASN1_CONTEXT_SPECIFIC | 0 |
		SEC_ASN1_CONSTRUCTED |
		SEC_ASN1_OPTIONAL,
	.offset = offsetof(SpcSignerInfo, signedAttrs),
	.sub = &SEC_AnyTemplate,
	.size = sizeof (SECItem)
	},
	{
	.kind = SEC_ASN1_INLINE,
	.offset = offsetof(SpcSignerInfo, signatureAlgorithm),
	.sub = &SECOID_AlgorithmIDTemplate,
	.size = sizeof (SECItem)
	},
	{
	.kind = SEC_ASN1_OCTET_STRING,
	.offset = offsetof(SpcSignerInfo, signature),
	.sub = &SEC_OctetStringTemplate,
	.size = sizeof (SECItem)
	},
#if 0
	{
	.kind = SEC_ASN1_CONTEXT_SPECIFIC | 1 |
		SEC_ASN1_CONSTRUCTED |
		SEC_ASN1_OPTIONAL |
		SEC_ASN1_EXPLICIT,
	.offset = offsetof(SpcSignerInfo, unsignedAttrs),
	.sub = &SEC_AnyTemplate,
	.size = sizeof (SECItem)
	},
#endif
	{ 0, }
};

int
generate_spc_signer_info(cms_context *cms, SpcSignerInfo *sip)
{
	if (!sip)
		return -1;

	SpcSignerInfo si;
	memset(&si, '\0', sizeof (si));

	if (SEC_ASN1EncodeInteger(cms->arena, &si.CMSVersion, 1) == NULL) {
		cms->log(cms, LOG_ERR, "could not encode CMSVersion: %s",
			PORT_ErrorToString(PORT_GetError()));
		goto err;
	}

	si.sid.signerType = signerTypeIssuerAndSerialNumber;
	si.sid.signerValue.iasn.issuer = cms->cert->derIssuer;
	si.sid.signerValue.iasn.serial = cms->cert->serialNumber;

	if (generate_algorithm_id(cms, &si.digestAlgorithm,
			digest_get_digest_oid(cms)) < 0)
		goto err;


	if (cms->raw_signature) {
		memcpy(&si.signedAttrs, cms->raw_signed_attrs,
			sizeof (si.signedAttrs));
		memcpy(&si.signature, cms->raw_signature, sizeof(si.signature));
	} else {
		if (generate_signed_attributes(cms, &si.signedAttrs) < 0)
			goto err;

		if (sign_blob(cms, &si.signature, &si.signedAttrs) < 0)
			goto err;
	}

	si.signedAttrs.data[0] = SEC_ASN1_CONTEXT_SPECIFIC | 0 |
				SEC_ASN1_CONSTRUCTED;

	if (generate_algorithm_id(cms, &si.signatureAlgorithm,
				digest_get_encryption_oid(cms)) < 0)
		goto err;

	if (generate_unsigned_attributes(cms, &si.unsignedAttrs) < 0)
		goto err;

	memcpy(sip, &si, sizeof(si));
	return 0;
err:
	return -1;
}

int
generate_authvar_signer_info(cms_context *cms, SpcSignerInfo *sip)
{
	SpcSignerInfo si;
	SECItem buf;

	if (!sip)
		return -1;

	memset(&si, '\0', sizeof (si));

	if (SEC_ASN1EncodeInteger(cms->arena, &si.CMSVersion, 1) == NULL) {
		cms->log(cms, LOG_ERR, "could not encode CMSVersion: %s",
			PORT_ErrorToString(PORT_GetError()));
		goto err;
	}

	si.sid.signerType = signerTypeIssuerAndSerialNumber;
	si.sid.signerValue.iasn.issuer = cms->cert->derIssuer;
	si.sid.signerValue.iasn.serial = cms->cert->serialNumber;

	if (generate_algorithm_id(cms, &si.digestAlgorithm,
			digest_get_digest_oid(cms)) < 0)
		goto err;

	si.signedAttrs.len = 0;
	si.signedAttrs.data = NULL;

	buf.len = cms->authbuf_len;
	buf.data = cms->authbuf;
	if (sign_blob(cms, &si.signature, &buf) < 0)
		goto err;

	if (generate_algorithm_id(cms, &si.signatureAlgorithm,
				digest_get_encryption_oid(cms)) < 0)
		goto err;

	si.unsignedAttrs.len = 0;
	si.unsignedAttrs.data = NULL;

	memcpy(sip, &si, sizeof(si));
	return 0;
err:
	return -1;
}

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