src/SignerInfo.c

#include <stdlib.h>
#include <memory.h>

#include "cose.h"
#include "cose_int.h"
#include "configure.h"
#include "crypto.h"

extern bool IsValidSignHandle(HCOSE_SIGN h);

bool IsValidSignerHandle(HCOSE_SIGNER h)
{
	if (h == NULL) return false;
	return true;
}

void _COSE_Signer_Free(COSE_SignerInfo * pSigner)
{
	COSE_FREE(pSigner, &pSigner->m_message.m_allocContext);

	return;
}


HCOSE_SIGNER COSE_Sign_GetSigner(HCOSE_SIGN cose, int iSigner, cose_errback * perr)
{
	int i;
	COSE_SignerInfo * p;

	if (!IsValidSignHandle(cose)) {
		if (perr != NULL) perr->err = COSE_ERR_INVALID_PARAMETER;
		return NULL;
	}

	p = ((COSE_SignMessage *)cose)->m_signerFirst;
	for (i = 0; i < iSigner; i++) {
		if (p == NULL) {
			if (perr != NULL) perr->err = COSE_ERR_INVALID_PARAMETER;
			return NULL;
		}
		p = p->m_signerNext;
	}
	return (HCOSE_SIGNER)p;
}

COSE_SignerInfo * _COSE_SignerInfo_Init_From_Object(cn_cbor * cbor, CBOR_CONTEXT_COMMA cose_errback * perr)
{
	COSE_SignerInfo * pSigner = NULL;

	pSigner = (COSE_SignerInfo *)COSE_CALLOC(1, sizeof(COSE_SignerInfo), context);
	CHECK_CONDITION(pSigner != NULL, COSE_ERR_OUT_OF_MEMORY);

	CHECK_CONDITION(cbor->type == CN_CBOR_ARRAY, COSE_ERR_INVALID_PARAMETER);

	if (!_COSE_Init_From_Object(&pSigner->m_message, cbor, CBOR_CONTEXT_PARAM_COMMA perr)) {
		_COSE_Signer_Free(pSigner);
		return NULL;
	}

	return pSigner;

errorReturn:
	if (pSigner != NULL) COSE_FREE(pSigner, context);
	return NULL;
}

byte RgbDontUse4[1024];

bool _COSE_Signer_sign(COSE_SignerInfo * pSigner, const cn_cbor * pcborBody, const cn_cbor * pcborProtected, cose_errback * perr)
{
#ifdef USE_CBOR_CONTEXT
	cn_cbor_context * context = &pSigner->m_message.m_allocContext;
#endif
	cn_cbor * pcborBody2 = NULL;
	cn_cbor * pcborProtected2 = NULL;
	cn_cbor * pcborProtectedSign = NULL;
	cn_cbor * pcborProtectedSign2 = NULL;
	cn_cbor * pArray = NULL;
	size_t cbToSign;
	byte * pbToSign = NULL;
	bool f;

	pArray = cn_cbor_array_create(CBOR_CONTEXT_PARAM_COMMA NULL);
	if (pArray == NULL) {
		if (perr != NULL) perr->err = COSE_ERR_OUT_OF_MEMORY;
	errorReturn:
		if (pcborBody2 != NULL) CN_CBOR_FREE(pcborBody2, context);
		if (pcborProtected2 != NULL) CN_CBOR_FREE(pcborProtected2, context);
		if (pArray != NULL) COSE_FREE(pArray, context);
		if (pbToSign != NULL) COSE_FREE(pbToSign, context);
		return false;
	}

	pcborProtectedSign = _COSE_encode_protected(&pSigner->m_message, perr);
	if (pcborProtectedSign == NULL) goto errorReturn;

	pcborBody2 = cn_cbor_data_create(pcborBody->v.bytes, (int) pcborBody->length, CBOR_CONTEXT_PARAM_COMMA NULL);
	CHECK_CONDITION(pcborBody2 != NULL, COSE_ERR_OUT_OF_MEMORY);

	pcborProtected2 = cn_cbor_data_create(pcborProtected->v.bytes, (int) pcborProtected->length, CBOR_CONTEXT_PARAM_COMMA NULL);
	CHECK_CONDITION(pcborProtected2 != NULL, COSE_ERR_OUT_OF_MEMORY);

	pcborProtectedSign2 = cn_cbor_data_create(pcborProtectedSign->v.bytes, (int) pcborProtectedSign->length, CBOR_CONTEXT_PARAM_COMMA NULL);
	CHECK_CONDITION(pcborProtectedSign2 != NULL, COSE_ERR_OUT_OF_MEMORY);

	CHECK_CONDITION(cn_cbor_array_append(pArray, pcborProtected2, NULL), COSE_ERR_CBOR);
	CHECK_CONDITION(cn_cbor_array_append(pArray, pcborProtectedSign2, NULL), COSE_ERR_CBOR);
	CHECK_CONDITION(cn_cbor_array_append(pArray, cn_cbor_data_create(NULL, 0, CBOR_CONTEXT_PARAM_COMMA NULL), NULL), COSE_ERR_CBOR);
	CHECK_CONDITION(cn_cbor_array_append(pArray, pcborBody2, NULL), COSE_ERR_CBOR);

	cbToSign = cn_cbor_encoder_write(RgbDontUse4, 0, sizeof(RgbDontUse4), pArray);
	CHECK_CONDITION(cbToSign > 0, COSE_ERR_CBOR);
	pbToSign = (byte *)COSE_CALLOC(cbToSign, 1, context);
	CHECK_CONDITION(pbToSign != NULL, COSE_ERR_OUT_OF_MEMORY);
	CHECK_CONDITION(cn_cbor_encoder_write(pbToSign, 0, cbToSign, pArray), COSE_ERR_CBOR);

	f = ECDSA_Sign(pSigner, pbToSign, cbToSign, perr);

	COSE_FREE(pbToSign, context);
	CN_CBOR_FREE(pArray, context);

	return f;
}

bool COSE_Signer_SetKey(HCOSE_SIGNER h, const cn_cbor * pKey, cose_errback * perror)
{
	COSE_SignerInfo * p;

	if (!IsValidSignerHandle(h) || (pKey == NULL)) {
		if (perror != NULL) perror->err = COSE_ERR_INVALID_PARAMETER;
		return false;
	}

	p = (COSE_SignerInfo *)h;
	p->m_pkey = pKey;

	return true;
}

byte RgbDontUseSign[8 * 1024];

bool _COSE_Signer_validate(COSE_SignMessage * pSign, COSE_SignerInfo * pSigner, const byte * pbContent, size_t cbContent, const byte * pbProtected, size_t cbProtected, cose_errback * perr)
{
	cn_cbor_errback cbor_error;
	byte * pbAuthData = NULL;
	int cbitKey = 0;
	byte * pbKeyIn = NULL;

	int alg;
	const cn_cbor * cn = NULL;

	byte * pbKey = pbKeyIn;
#ifdef USE_CBOR_CONTEXT
	cn_cbor_context * context = NULL;
#endif
	ssize_t cbAuthData;
	cn_cbor * pAuthData = NULL;
	cn_cbor * ptmp = NULL;

#ifdef USE_CBOR_CONTEXT
	context = &pSign->m_message.m_allocContext;
#endif

	cn = _COSE_map_get_int(&pSigner->m_message, COSE_Header_Algorithm, COSE_BOTH, perr);
	if (cn == NULL) goto errorReturn;

	if (cn->type == CN_CBOR_TEXT) {
		FAIL_CONDITION(COSE_ERR_UNKNOWN_ALGORITHM);
	}
	else {
		CHECK_CONDITION((cn->type == CN_CBOR_UINT || cn->type == CN_CBOR_INT), COSE_ERR_INVALID_PARAMETER);

		alg = (int)cn->v.uint;
	}

	//  Build protected headers

	cn_cbor * cnProtected = _COSE_arrayget_int(&pSigner->m_message, INDEX_PROTECTED);
	CHECK_CONDITION((cnProtected != NULL) && (cnProtected->type == CN_CBOR_BYTES), COSE_ERR_INVALID_PARAMETER);

	cn_cbor * cnSignature = _COSE_arrayget_int(&pSigner->m_message, INDEX_SIGNATURE);
	CHECK_CONDITION((cnSignature != NULL) && (cnSignature->type == CN_CBOR_BYTES), COSE_ERR_INVALID_PARAMETER);

	//  Build authenticated data
	pbAuthData = NULL;
	pAuthData = cn_cbor_array_create(CBOR_CONTEXT_PARAM_COMMA &cbor_error);
	CHECK_CONDITION_CBOR(pAuthData != NULL, cbor_error);

	ptmp = cn_cbor_string_create("Signature", CBOR_CONTEXT_PARAM_COMMA &cbor_error);
	CHECK_CONDITION_CBOR(ptmp != NULL, cbor_error);
	CHECK_CONDITION_CBOR(cn_cbor_array_append(pAuthData, ptmp, &cbor_error), cbor_error);

	ptmp = cn_cbor_data_create(pbProtected, (int) cbProtected, CBOR_CONTEXT_PARAM_COMMA &cbor_error);
	CHECK_CONDITION_CBOR(ptmp != NULL, cbor_error);
	CHECK_CONDITION_CBOR(cn_cbor_array_append(pAuthData, ptmp, &cbor_error), cbor_error);

	ptmp = cn_cbor_data_create(cnProtected->v.bytes, (int)cnProtected->length, CBOR_CONTEXT_PARAM_COMMA &cbor_error);
	CHECK_CONDITION_CBOR(ptmp != NULL, cbor_error);
	CHECK_CONDITION_CBOR(cn_cbor_array_append(pAuthData, ptmp, &cbor_error), cbor_error);

	ptmp = cn_cbor_data_create(NULL, 0, CBOR_CONTEXT_PARAM_COMMA &cbor_error);
	CHECK_CONDITION_CBOR(ptmp != NULL, cbor_error);
	CHECK_CONDITION_CBOR(cn_cbor_array_append(pAuthData, ptmp, &cbor_error), cbor_error);

	ptmp = cn_cbor_data_create(pbContent, (int) cbContent, CBOR_CONTEXT_PARAM_COMMA &cbor_error);
	CHECK_CONDITION_CBOR(ptmp != NULL, cbor_error);
	CHECK_CONDITION_CBOR(cn_cbor_array_append(pAuthData, ptmp, &cbor_error), cbor_error);

	cbAuthData = cn_cbor_encoder_write(RgbDontUseSign, 0, sizeof(RgbDontUseSign), pAuthData);
	pbAuthData = (byte *)COSE_CALLOC(cbAuthData, 1, context);
	CHECK_CONDITION(pbAuthData != NULL, COSE_ERR_OUT_OF_MEMORY);
	CHECK_CONDITION((cn_cbor_encoder_write(pbAuthData, 0, cbAuthData + 1, pAuthData) == cbAuthData), COSE_ERR_CBOR); // M00HACK

	switch (alg) {
	case COSE_Algorithm_ECDSA_SHA_256:
		if (!ECDSA_Verify(pSigner, pbAuthData, cbAuthData, cnSignature->v.bytes, cnSignature->length, perr)) goto errorReturn;
		break;

	default:
		FAIL_CONDITION(COSE_ERR_UNKNOWN_ALGORITHM);
		break;
	}

	if (pbAuthData != NULL) COSE_FREE(pbAuthData, context);
	if (pAuthData != NULL) cn_cbor_free(pAuthData CBOR_CONTEXT_PARAM);
	if ((pbKey != NULL) && (pbKeyIn == NULL)) {
		memset(pbKey, 0xff, cbitKey / 8);
		COSE_FREE(pbKey, context);
	}

	return true;

errorReturn:
	if (pbAuthData != NULL) COSE_FREE(pbAuthData, context);
	if (pAuthData != NULL) cn_cbor_free(pAuthData CBOR_CONTEXT_PARAM);
	if ((pbKey != NULL) && (pbKeyIn == NULL)) {
		memset(pbKey, 0xff, cbitKey / 8);
		COSE_FREE(pbKey, context);
	}

	return false;
}