/*
 * Verification stuff.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include <stdio.h>
#include "cryptohi.h"
#include "sechash.h"
#include "keyhi.h"
#include "secasn1.h"
#include "secoid.h"
#include "pk11func.h"
#include "secdig.h"
#include "secerr.h"
#include "keyi.h"

/*
** Decrypt signature block using public key
** Store the hash algorithm oid tag in *tagp
** Store the digest in the digest buffer
** Store the digest length in *digestlen
** XXX this is assuming that the signature algorithm has WITH_RSA_ENCRYPTION
*/
static SECStatus
DecryptSigBlock(SECOidTag *tagp, unsigned char *digest,
		unsigned int *digestlen, unsigned int maxdigestlen,
		SECKEYPublicKey *key, const SECItem *sig, char *wincx)
{
    SGNDigestInfo *di   = NULL;
    unsigned char *buf  = NULL;
    SECStatus      rv;
    SECOidTag      tag;
    SECItem        it;

    if (key == NULL) goto loser;

    it.len  = SECKEY_PublicKeyStrength(key);
    if (!it.len) goto loser;
    it.data = buf = (unsigned char *)PORT_Alloc(it.len);
    if (!buf) goto loser;

    /* decrypt the block */
    rv = PK11_VerifyRecover(key, (SECItem *)sig, &it, wincx);
    if (rv != SECSuccess) goto loser;

    di = SGN_DecodeDigestInfo(&it);
    if (di == NULL) goto sigloser;

    /*
    ** Finally we have the digest info; now we can extract the algorithm
    ** ID and the signature block
    */
    tag = SECOID_GetAlgorithmTag(&di->digestAlgorithm);
    /* Check that tag is an appropriate algorithm */
    if (tag == SEC_OID_UNKNOWN) {
	goto sigloser;
    }
    /* make sure the "parameters" are not too bogus. */
    if (di->digestAlgorithm.parameters.len > 2) {
	goto sigloser;
    }
    if (di->digest.len > maxdigestlen) {
	PORT_SetError(SEC_ERROR_OUTPUT_LEN);
	goto loser;
    }
    PORT_Memcpy(digest, di->digest.data, di->digest.len);
    *tagp = tag;
    *digestlen = di->digest.len;
    goto done;

  sigloser:
    PORT_SetError(SEC_ERROR_BAD_SIGNATURE);

  loser:
    rv = SECFailure;

  done:
    if (di   != NULL) SGN_DestroyDigestInfo(di);
    if (buf  != NULL) PORT_Free(buf);
    
    return rv;
}


struct VFYContextStr {
    SECOidTag hashAlg;  /* the hash algorithm */
    SECKEYPublicKey *key;
    /*
     * This buffer holds either the digest or the full signature
     * depending on the type of the signature (key->keyType).  It is
     * defined as a union to make sure it always has enough space.
     *
     * Use the "buffer" union member to reference the buffer.
     * Note: do not take the size of the "buffer" union member.  Take
     * the size of the union or some other union member instead.
     */
    union {
	unsigned char buffer[1];

	/* the digest in the decrypted RSA signature */
	unsigned char rsadigest[HASH_LENGTH_MAX];
	/* the full DSA signature... 40 bytes */
	unsigned char dsasig[DSA_MAX_SIGNATURE_LEN];
	/* the full ECDSA signature */
	unsigned char ecdsasig[2 * MAX_ECKEY_LEN];
    } u;
    unsigned int rsadigestlen;
    void * wincx;
    void *hashcx;
    const SECHashObject *hashobj;
    SECOidTag encAlg;  /* enc alg */
    PRBool hasSignature;  /* true if the signature was provided in the
                           * VFY_CreateContext call.  If false, the
                           * signature must be provided with a
                           * VFY_EndWithSignature call. */
};

/*
 * decode the ECDSA or DSA signature from it's DER wrapping.
 * The unwrapped/raw signature is placed in the buffer pointed
 * to by dsig and has enough room for len bytes.
 */
static SECStatus
decodeECorDSASignature(SECOidTag algid, const SECItem *sig, unsigned char *dsig,
		       unsigned int len) {
    SECItem *dsasig = NULL; /* also used for ECDSA */
    SECStatus rv=SECSuccess;

    if ((algid != SEC_OID_ANSIX9_DSA_SIGNATURE) &&
	(algid != SEC_OID_ANSIX962_EC_PUBLIC_KEY) ) {
        if (sig->len != len) {
	    PORT_SetError(SEC_ERROR_BAD_DER);
	    return SECFailure;
	} 

	PORT_Memcpy(dsig, sig->data, sig->len);
	return SECSuccess;
    }

    if (algid ==  SEC_OID_ANSIX962_EC_PUBLIC_KEY) {
	if (len > MAX_ECKEY_LEN * 2) {
	    PORT_SetError(SEC_ERROR_BAD_DER);
	    return SECFailure;
	}
    }
    dsasig = DSAU_DecodeDerSigToLen((SECItem *)sig, len);

    if ((dsasig == NULL) || (dsasig->len != len)) {
	rv = SECFailure;
    } else {
	PORT_Memcpy(dsig, dsasig->data, dsasig->len);
    }

    if (dsasig != NULL) SECITEM_FreeItem(dsasig, PR_TRUE);
    if (rv == SECFailure) PORT_SetError(SEC_ERROR_BAD_DER);
    return rv;
}

const SEC_ASN1Template hashParameterTemplate[] =
{
    { SEC_ASN1_SEQUENCE, 0, NULL, sizeof(SECItem) },
    { SEC_ASN1_OBJECT_ID, 0 },
    { SEC_ASN1_SKIP_REST },
    { 0, }
};

/*
 * Pulls the hash algorithm, signing algorithm, and key type out of a
 * composite algorithm.
 *
 * sigAlg: the composite algorithm to dissect.
 * hashalg: address of a SECOidTag which will be set with the hash algorithm.
 * encalg: address of a SECOidTag which will be set with the signing alg.
 *
 * Returns: SECSuccess if the algorithm was acceptable, SECFailure if the
 *	algorithm was not found or was not a signing algorithm.
 */
SECStatus
sec_DecodeSigAlg(const SECKEYPublicKey *key, SECOidTag sigAlg, 
             const SECItem *param, SECOidTag *encalg, SECOidTag *hashalg)
{
    int len;
    PLArenaPool *arena;
    SECStatus rv;
    SECItem oid;

    PR_ASSERT(hashalg!=NULL);
    PR_ASSERT(encalg!=NULL);

    switch (sigAlg) {
      /* We probably shouldn't be generating MD2 signatures either */
      case SEC_OID_PKCS1_MD2_WITH_RSA_ENCRYPTION:
        *hashalg = SEC_OID_MD2;
	break;
      case SEC_OID_PKCS1_MD5_WITH_RSA_ENCRYPTION:
        *hashalg = SEC_OID_MD5;
	break;
      case SEC_OID_PKCS1_SHA1_WITH_RSA_ENCRYPTION:
      case SEC_OID_ISO_SHA_WITH_RSA_SIGNATURE:
      case SEC_OID_ISO_SHA1_WITH_RSA_SIGNATURE:
        *hashalg = SEC_OID_SHA1;
	break;
      case SEC_OID_PKCS1_RSA_ENCRYPTION:
      case SEC_OID_PKCS1_RSA_PSS_SIGNATURE:
        *hashalg = SEC_OID_UNKNOWN; /* get it from the RSA signature */
	break;

      case SEC_OID_ANSIX962_ECDSA_SHA224_SIGNATURE:
      case SEC_OID_PKCS1_SHA224_WITH_RSA_ENCRYPTION:
      case SEC_OID_NIST_DSA_SIGNATURE_WITH_SHA224_DIGEST:
	*hashalg = SEC_OID_SHA224;
	break;
      case SEC_OID_ANSIX962_ECDSA_SHA256_SIGNATURE:
      case SEC_OID_PKCS1_SHA256_WITH_RSA_ENCRYPTION:
      case SEC_OID_NIST_DSA_SIGNATURE_WITH_SHA256_DIGEST:
	*hashalg = SEC_OID_SHA256;
	break;
      case SEC_OID_ANSIX962_ECDSA_SHA384_SIGNATURE:
      case SEC_OID_PKCS1_SHA384_WITH_RSA_ENCRYPTION:
	*hashalg = SEC_OID_SHA384;
	break;
      case SEC_OID_ANSIX962_ECDSA_SHA512_SIGNATURE:
      case SEC_OID_PKCS1_SHA512_WITH_RSA_ENCRYPTION:
	*hashalg = SEC_OID_SHA512;
	break;

      /* what about normal DSA? */
      case SEC_OID_ANSIX9_DSA_SIGNATURE_WITH_SHA1_DIGEST:
      case SEC_OID_BOGUS_DSA_SIGNATURE_WITH_SHA1_DIGEST:
      case SEC_OID_ANSIX962_ECDSA_SHA1_SIGNATURE:
        *hashalg = SEC_OID_SHA1;
	break;
      case SEC_OID_MISSI_DSS:
      case SEC_OID_MISSI_KEA_DSS:
      case SEC_OID_MISSI_KEA_DSS_OLD:
      case SEC_OID_MISSI_DSS_OLD:
        *hashalg = SEC_OID_SHA1;
	break;
      case SEC_OID_ANSIX962_ECDSA_SIGNATURE_RECOMMENDED_DIGEST:
	/* This is an EC algorithm. Recommended means the largest
	 * hash algorithm that is not reduced by the keysize of 
	 * the EC algorithm. Note that key strength is in bytes and
	 * algorithms are specified in bits. Never use an algorithm
	 * weaker than sha1. */
	len = SECKEY_PublicKeyStrength(key);
	if (len < 28) { /* 28 bytes == 224 bits */
	    *hashalg = SEC_OID_SHA1;
	} else if (len < 32) { /* 32 bytes == 256 bits */
	    *hashalg = SEC_OID_SHA224;
	} else if (len < 48) { /* 48 bytes == 384 bits */
	    *hashalg = SEC_OID_SHA256;
	} else if (len < 64) { /* 48 bytes == 512 bits */
	    *hashalg = SEC_OID_SHA384;
	} else {
	    /* use the largest in this case */
	    *hashalg = SEC_OID_SHA512;
	}
	break;
      case SEC_OID_ANSIX962_ECDSA_SIGNATURE_SPECIFIED_DIGEST:
	if (param == NULL) {
	    PORT_SetError(SEC_ERROR_INVALID_ALGORITHM);
	    return SECFailure;
	}
	arena = PORT_NewArena(DER_DEFAULT_CHUNKSIZE);
	if (arena == NULL) {
	    return SECFailure;
	}
	rv = SEC_QuickDERDecodeItem(arena, &oid, hashParameterTemplate, param);
	if (rv == SECSuccess) {
            *hashalg = SECOID_FindOIDTag(&oid);
        }
        PORT_FreeArena(arena, PR_FALSE);
        if (rv != SECSuccess) {
	    return rv;
	}
	/* only accept hash algorithms */
	if (HASH_GetHashTypeByOidTag(*hashalg) == HASH_AlgNULL) {
	    /* error set by HASH_GetHashTypeByOidTag */
	    return SECFailure;
	}
	break;
      /* we don't implement MD4 hashes */
      case SEC_OID_PKCS1_MD4_WITH_RSA_ENCRYPTION:
      default:
	PORT_SetError(SEC_ERROR_INVALID_ALGORITHM);
	return SECFailure;
    }
    /* get the "encryption" algorithm */ 
    switch (sigAlg) {
      case SEC_OID_PKCS1_RSA_ENCRYPTION:
      case SEC_OID_PKCS1_MD2_WITH_RSA_ENCRYPTION:
      case SEC_OID_PKCS1_MD5_WITH_RSA_ENCRYPTION:
      case SEC_OID_PKCS1_SHA1_WITH_RSA_ENCRYPTION:
      case SEC_OID_ISO_SHA_WITH_RSA_SIGNATURE:
      case SEC_OID_ISO_SHA1_WITH_RSA_SIGNATURE:
      case SEC_OID_PKCS1_SHA224_WITH_RSA_ENCRYPTION:
      case SEC_OID_PKCS1_SHA256_WITH_RSA_ENCRYPTION:
      case SEC_OID_PKCS1_SHA384_WITH_RSA_ENCRYPTION:
      case SEC_OID_PKCS1_SHA512_WITH_RSA_ENCRYPTION:
	*encalg = SEC_OID_PKCS1_RSA_ENCRYPTION;
	break;
      case SEC_OID_PKCS1_RSA_PSS_SIGNATURE:
	*encalg = SEC_OID_PKCS1_RSA_PSS_SIGNATURE;
	break;

      /* what about normal DSA? */
      case SEC_OID_ANSIX9_DSA_SIGNATURE_WITH_SHA1_DIGEST:
      case SEC_OID_BOGUS_DSA_SIGNATURE_WITH_SHA1_DIGEST:
      case SEC_OID_NIST_DSA_SIGNATURE_WITH_SHA224_DIGEST:
      case SEC_OID_NIST_DSA_SIGNATURE_WITH_SHA256_DIGEST:
	*encalg = SEC_OID_ANSIX9_DSA_SIGNATURE;
	break;
      case SEC_OID_MISSI_DSS:
      case SEC_OID_MISSI_KEA_DSS:
      case SEC_OID_MISSI_KEA_DSS_OLD:
      case SEC_OID_MISSI_DSS_OLD:
	*encalg = SEC_OID_MISSI_DSS;
	break;
      case SEC_OID_ANSIX962_ECDSA_SHA1_SIGNATURE:
      case SEC_OID_ANSIX962_ECDSA_SHA224_SIGNATURE:
      case SEC_OID_ANSIX962_ECDSA_SHA256_SIGNATURE:
      case SEC_OID_ANSIX962_ECDSA_SHA384_SIGNATURE:
      case SEC_OID_ANSIX962_ECDSA_SHA512_SIGNATURE:
      case SEC_OID_ANSIX962_ECDSA_SIGNATURE_RECOMMENDED_DIGEST:
      case SEC_OID_ANSIX962_ECDSA_SIGNATURE_SPECIFIED_DIGEST:
	*encalg = SEC_OID_ANSIX962_EC_PUBLIC_KEY;
	break;
      /* we don't implement MD4 hashes */
      case SEC_OID_PKCS1_MD4_WITH_RSA_ENCRYPTION:
      default:
	PORT_SetError(SEC_ERROR_INVALID_ALGORITHM);
	return SECFailure;
    }
    return SECSuccess;
}

/*
 * we can verify signatures that come from 2 different sources:
 *  one in with the signature contains a signature oid, and the other
 *  in which the signature is managed by a Public key (encAlg) oid
 *  and a hash oid. The latter is the more basic, so that's what
 *  our base vfyCreate function takes.
 *
 * There is one noteworthy corner case, if we are using an RSA key, and the
 * signature block is provided, then the hashAlg can be specified as 
 * SEC_OID_UNKNOWN. In this case, verify will use the hash oid supplied
 * in the RSA signature block.
 */
static VFYContext *
vfy_CreateContext(const SECKEYPublicKey *key, const SECItem *sig, 
	SECOidTag encAlg, SECOidTag hashAlg, SECOidTag *hash, void *wincx)
{
    VFYContext *cx;
    SECStatus rv;
    unsigned int sigLen;
    KeyType type;

    /* make sure the encryption algorithm matches the key type */
    /* RSA-PSS algorithm can be used with both rsaKey and rsaPssKey */
    type = seckey_GetKeyType(encAlg);
    if ((key->keyType != type) &&
	((key->keyType != rsaKey) || (type != rsaPssKey))) {
	PORT_SetError(SEC_ERROR_PKCS7_KEYALG_MISMATCH);
	return NULL;
    }

    cx = (VFYContext*) PORT_ZAlloc(sizeof(VFYContext));
    if (cx == NULL) {
	goto loser;
    }

    cx->wincx = wincx;
    cx->hasSignature = (sig != NULL);
    cx->encAlg = encAlg;
    cx->hashAlg = hashAlg;
    cx->key = SECKEY_CopyPublicKey(key);
    rv = SECSuccess;
    if (sig) {
	switch (type) {
	case rsaKey:
	    rv = DecryptSigBlock(&cx->hashAlg, cx->u.buffer, &cx->rsadigestlen,
			HASH_LENGTH_MAX, cx->key, sig, (char*)wincx);
	    if (cx->hashAlg != hashAlg && hashAlg != SEC_OID_UNKNOWN) {
		PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
		rv = SECFailure;	
	    }
	    break;
	case dsaKey:
	case ecKey:
	    sigLen = SECKEY_SignatureLen(key);
	    if (sigLen == 0) {
		/* error set by SECKEY_SignatureLen */
		rv = SECFailure;	
		break;
	    }
	    rv = decodeECorDSASignature(encAlg, sig, cx->u.buffer, sigLen);
 	    break;
	default:
	    rv = SECFailure;
	    PORT_SetError(SEC_ERROR_UNSUPPORTED_KEYALG);
	    break;
	}
    }

    if (rv) goto loser;

    /* check hash alg again, RSA may have changed it.*/
    if (HASH_GetHashTypeByOidTag(cx->hashAlg) == HASH_AlgNULL) {
	/* error set by HASH_GetHashTypeByOidTag */
	goto loser;
    }

    if (hash) {
	*hash = cx->hashAlg;
    }
    return cx;

  loser:
    if (cx) {
	VFY_DestroyContext(cx, PR_TRUE);
    }
    return 0;
}

VFYContext *
VFY_CreateContext(SECKEYPublicKey *key, SECItem *sig, SECOidTag sigAlg,
		  void *wincx)
{
    SECOidTag encAlg, hashAlg;
    SECStatus rv = sec_DecodeSigAlg(key, sigAlg, NULL, &encAlg, &hashAlg);
    if (rv != SECSuccess) {
	return NULL;
    }
    return vfy_CreateContext(key, sig, encAlg, hashAlg, NULL, wincx);
}

VFYContext *
VFY_CreateContextDirect(const SECKEYPublicKey *key, const SECItem *sig, 
			SECOidTag encAlg, SECOidTag hashAlg, 
			SECOidTag *hash, void *wincx)
{
  return vfy_CreateContext(key, sig, encAlg, hashAlg, hash, wincx);
}

VFYContext *
VFY_CreateContextWithAlgorithmID(const SECKEYPublicKey *key, const SECItem *sig,
	      const SECAlgorithmID *sigAlgorithm, SECOidTag *hash, void *wincx)
{
    SECOidTag encAlg, hashAlg;
    SECStatus rv = sec_DecodeSigAlg(key, 
		    SECOID_GetAlgorithmTag((SECAlgorithmID *)sigAlgorithm), 
		    &sigAlgorithm->parameters, &encAlg, &hashAlg);
    if (rv != SECSuccess) {
	return NULL;
    }
    return vfy_CreateContext(key, sig, encAlg, hashAlg, hash, wincx);
}

void
VFY_DestroyContext(VFYContext *cx, PRBool freeit)
{
    if (cx) {
	if (cx->hashcx != NULL) {
	    (*cx->hashobj->destroy)(cx->hashcx, PR_TRUE);
	    cx->hashcx = NULL;
	}
	if (cx->key) {
	    SECKEY_DestroyPublicKey(cx->key);
	}
	if (freeit) {
	    PORT_ZFree(cx, sizeof(VFYContext));
	}
    }
}

SECStatus
VFY_Begin(VFYContext *cx)
{
    if (cx->hashcx != NULL) {
	(*cx->hashobj->destroy)(cx->hashcx, PR_TRUE);
	cx->hashcx = NULL;
    }

    cx->hashobj = HASH_GetHashObjectByOidTag(cx->hashAlg);
    if (!cx->hashobj) 
	return SECFailure;	/* error code is set */

    cx->hashcx = (*cx->hashobj->create)();
    if (cx->hashcx == NULL)
	return SECFailure;

    (*cx->hashobj->begin)(cx->hashcx);
    return SECSuccess;
}

SECStatus
VFY_Update(VFYContext *cx, const unsigned char *input, unsigned inputLen)
{
    if (cx->hashcx == NULL) {
	PORT_SetError(SEC_ERROR_INVALID_ARGS);
	return SECFailure;
    }
    (*cx->hashobj->update)(cx->hashcx, input, inputLen);
    return SECSuccess;
}

SECStatus
VFY_EndWithSignature(VFYContext *cx, SECItem *sig)
{
    unsigned char final[HASH_LENGTH_MAX];
    unsigned part;
    SECItem hash,dsasig; /* dsasig is also used for ECDSA */
    SECStatus rv;

    if ((cx->hasSignature == PR_FALSE) && (sig == NULL)) {
	PORT_SetError(SEC_ERROR_INVALID_ARGS);
	return SECFailure;
    }

    if (cx->hashcx == NULL) {
	PORT_SetError(SEC_ERROR_INVALID_ARGS);
	return SECFailure;
    }
    (*cx->hashobj->end)(cx->hashcx, final, &part, sizeof(final));
    switch (cx->key->keyType) {
      case ecKey:
      case dsaKey:
	dsasig.data = cx->u.buffer;
	dsasig.len = SECKEY_SignatureLen(cx->key);
	if (dsasig.len == 0) {
	    return SECFailure;
	} 
	if (sig) {
	    rv = decodeECorDSASignature(cx->encAlg, sig, dsasig.data,
					dsasig.len);
	    if (rv != SECSuccess) {
		PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
		return SECFailure;
	    }
	} 
	hash.data = final;
	hash.len = part;
	if (PK11_Verify(cx->key,&dsasig,&hash,cx->wincx) != SECSuccess) {
		PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
		return SECFailure;
	}
	break;
      case rsaKey:
	if (sig) {
	    SECOidTag hashid = SEC_OID_UNKNOWN;
	    rv = DecryptSigBlock(&hashid, cx->u.buffer, &cx->rsadigestlen,
		    HASH_LENGTH_MAX, cx->key, sig, (char*)cx->wincx);
	    if ((rv != SECSuccess) || (hashid != cx->hashAlg)) {
		PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
		return SECFailure;
	    }
	}
	if ((part != cx->rsadigestlen) ||
	    PORT_Memcmp(final, cx->u.buffer, part)) {
	    PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
	    return SECFailure;
	}
	break;
      default:
	PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
	return SECFailure; /* shouldn't happen */
    }
    return SECSuccess;
}

SECStatus
VFY_End(VFYContext *cx)
{
    return VFY_EndWithSignature(cx,NULL);
}

/************************************************************************/
/*
 * Verify that a previously-computed digest matches a signature.
 */
static SECStatus
vfy_VerifyDigest(const SECItem *digest, const SECKEYPublicKey *key, 
		 const SECItem *sig, SECOidTag encAlg, SECOidTag hashAlg,
		 void *wincx)
{
    SECStatus rv;
    VFYContext *cx;
    SECItem dsasig; /* also used for ECDSA */

    rv = SECFailure;

    cx = vfy_CreateContext(key, sig, encAlg, hashAlg, NULL, wincx);
    if (cx != NULL) {
	switch (key->keyType) {
	case rsaKey:
	    if ((digest->len != cx->rsadigestlen) ||
		PORT_Memcmp(digest->data, cx->u.buffer, digest->len)) {
		PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
	    } else {
		rv = SECSuccess;
	    }
	    break;
	case dsaKey:
	case ecKey:
	    dsasig.data = cx->u.buffer;
	    dsasig.len = SECKEY_SignatureLen(cx->key);
	    if (dsasig.len == 0) {
		break;
	    }
	    if (PK11_Verify(cx->key, &dsasig, (SECItem *)digest, cx->wincx)
		!= SECSuccess) {
		PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
	    } else {
		rv = SECSuccess;
	    }
	    break;
	default:
	    break;
	}
	VFY_DestroyContext(cx, PR_TRUE);
    }
    return rv;
}

SECStatus
VFY_VerifyDigestDirect(const SECItem *digest, const SECKEYPublicKey *key, 
		       const SECItem *sig, SECOidTag encAlg, 
		       SECOidTag hashAlg, void *wincx)
{
    return vfy_VerifyDigest(digest, key, sig, encAlg, hashAlg, wincx);
}

SECStatus
VFY_VerifyDigest(SECItem *digest, SECKEYPublicKey *key, SECItem *sig,
		 SECOidTag algid, void *wincx)
{
    SECOidTag encAlg, hashAlg;
    SECStatus rv = sec_DecodeSigAlg(key, algid, NULL, &encAlg, &hashAlg);
    if (rv != SECSuccess) {
	return SECFailure;
    }
    return vfy_VerifyDigest(digest, key, sig, encAlg, hashAlg, wincx);
}

/*
 * this function takes an optional hash oid, which the digest function
 * will be compared with our target hash value.
 */
SECStatus
VFY_VerifyDigestWithAlgorithmID(const SECItem *digest, 
		const SECKEYPublicKey *key, const SECItem *sig, 
		const SECAlgorithmID *sigAlgorithm, 
		SECOidTag hashCmp, void *wincx)
{
    SECOidTag encAlg, hashAlg;
    SECStatus rv = sec_DecodeSigAlg(key, 
		    SECOID_GetAlgorithmTag((SECAlgorithmID *)sigAlgorithm), 
		    &sigAlgorithm->parameters, &encAlg, &hashAlg);
    if (rv != SECSuccess) {
	return rv;
    }
    if ( hashCmp != SEC_OID_UNKNOWN && 
	 hashAlg != SEC_OID_UNKNOWN &&
	 hashCmp != hashAlg) {
	PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
	return SECFailure;
    }
    return vfy_VerifyDigest(digest, key, sig, encAlg, hashAlg, wincx);
}

static SECStatus
vfy_VerifyData(const unsigned char *buf, int len, const SECKEYPublicKey *key,
	       const SECItem *sig, SECOidTag encAlg, SECOidTag hashAlg,
	       SECOidTag *hash, void *wincx)
{
    SECStatus rv;
    VFYContext *cx;

    cx = vfy_CreateContext(key, sig, encAlg, hashAlg, hash, wincx);
    if (cx == NULL)
	return SECFailure;

    rv = VFY_Begin(cx);
    if (rv == SECSuccess) {
	rv = VFY_Update(cx, (unsigned char *)buf, len);
	if (rv == SECSuccess)
	    rv = VFY_End(cx);
    }

    VFY_DestroyContext(cx, PR_TRUE);
    return rv;
}

SECStatus
VFY_VerifyDataDirect(const unsigned char *buf, int len, 
		     const SECKEYPublicKey *key, const SECItem *sig,
		     SECOidTag encAlg, SECOidTag hashAlg,
		     SECOidTag *hash, void *wincx)
{
    return vfy_VerifyData(buf, len, key, sig, encAlg, hashAlg, hash, wincx);
}

SECStatus
VFY_VerifyData(const unsigned char *buf, int len, const SECKEYPublicKey *key,
	       const SECItem *sig, SECOidTag algid, void *wincx)
{
    SECOidTag encAlg, hashAlg;
    SECStatus rv = sec_DecodeSigAlg(key, algid, NULL, &encAlg, &hashAlg);
    if (rv != SECSuccess) {
	return rv;
    }
    return vfy_VerifyData(buf, len, key, sig, encAlg, hashAlg, NULL, wincx);
}

SECStatus
VFY_VerifyDataWithAlgorithmID(const unsigned char *buf, int len, 
			      const SECKEYPublicKey *key,
			      const SECItem *sig, 
			      const SECAlgorithmID *sigAlgorithm, 
			      SECOidTag *hash, void *wincx)
{
    SECOidTag encAlg, hashAlg;
    SECOidTag sigAlg = SECOID_GetAlgorithmTag((SECAlgorithmID *)sigAlgorithm);
    SECStatus rv     = sec_DecodeSigAlg(key, sigAlg, 
		                &sigAlgorithm->parameters, &encAlg, &hashAlg);
    if (rv != SECSuccess) {
	return rv;
    }
    return vfy_VerifyData(buf, len, key, sig, encAlg, hashAlg, hash, wincx);
}