text: /*
   * validator/val_secalgo.c - validator security algorithm functions.
   *
   * Copyright (c) 2012, NLnet Labs. All rights reserved.
   *
   * This software is open source.
   * 
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 
   * Redistributions of source code must retain the above copyright notice,
   * this list of conditions and the following disclaimer.
   * 
   * Redistributions in binary form must reproduce the above copyright notice,
   * this list of conditions and the following disclaimer in the documentation
   * and/or other materials provided with the distribution.
   * 
   * Neither the name of the NLNET LABS nor the names of its contributors may
   * be used to endorse or promote products derived from this software without
   * specific prior written permission.
   * 
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
   * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
   * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  /**
   * \file
   *
   * This file contains helper functions for the validator module.
   * These functions take raw data buffers, formatted for crypto verification,
   * and do the library calls (for the crypto library in use).
   */
  #include "config.h"
  /* packed_rrset on top to define enum types (forced by c99 standard) */
  #include "util/data/packed_rrset.h"
  #include "validator/val_secalgo.h"
  #include "validator/val_nsec3.h"
  #include "util/log.h"
  #include "sldns/rrdef.h"
  #include "sldns/keyraw.h"
  #include "sldns/sbuffer.h"
  
  #if !defined(HAVE_SSL) && !defined(HAVE_NSS) && !defined(HAVE_NETTLE)
  #error "Need crypto library to do digital signature cryptography"
  #endif
  
  /* OpenSSL implementation */
  #ifdef HAVE_SSL
  #ifdef HAVE_OPENSSL_ERR_H
  #include <openssl/err.h>
  #endif
  
  #ifdef HAVE_OPENSSL_RAND_H
  #include <openssl/rand.h>
  #endif
  
  #ifdef HAVE_OPENSSL_CONF_H
  #include <openssl/conf.h>
  #endif
  
  #ifdef HAVE_OPENSSL_ENGINE_H
  #include <openssl/engine.h>
  #endif
  
  /** fake DSA support for unit tests */
  int fake_dsa = 0;
  /** fake SHA1 support for unit tests */
  int fake_sha1 = 0;
  
  /**
   * Output a libcrypto openssl error to the logfile.
   * @param str: string to add to it.
   * @param e: the error to output, error number from ERR_get_error().
   */
  static void
  log_crypto_error(const char* str, unsigned long e)
  {
  	char buf[128];
  	/* or use ERR_error_string if ERR_error_string_n is not avail TODO */
  	ERR_error_string_n(e, buf, sizeof(buf));
  	/* buf now contains */
  	/* error:[error code]:[library name]:[function name]:[reason string] */
  	log_err("%s crypto %s", str, buf);
  }
  
  /* return size of digest if supported, or 0 otherwise */
  size_t
  nsec3_hash_algo_size_supported(int id)
  {
  	switch(id) {
  	case NSEC3_HASH_SHA1:
  		return SHA_DIGEST_LENGTH;
  	default:
  		return 0;
  	}
  }
  
  /* perform nsec3 hash. return false on failure */
  int
  secalgo_nsec3_hash(int algo, unsigned char* buf, size_t len,
          unsigned char* res)
  {
  	switch(algo) {
  	case NSEC3_HASH_SHA1:
  #ifdef OPENSSL_FIPS
  		if(!sldns_digest_evp(buf, len, res, EVP_sha1()))
  			log_crypto_error("could not digest with EVP_sha1",
  				ERR_get_error());
  #else
  		(void)SHA1(buf, len, res);
  #endif
  		return 1;
  	default:
  		return 0;
  	}
  }
  
  void
  secalgo_hash_sha256(unsigned char* buf, size_t len, unsigned char* res)
  {
  #ifdef OPENSSL_FIPS
  	if(!sldns_digest_evp(buf, len, res, EVP_sha256()))
  		log_crypto_error("could not digest with EVP_sha256",
  			ERR_get_error());
  #else
  	(void)SHA256(buf, len, res);
  #endif
  }
  
  /**
   * Return size of DS digest according to its hash algorithm.
   * @param algo: DS digest algo.
   * @return size in bytes of digest, or 0 if not supported.
   */
  size_t
  ds_digest_size_supported(int algo)
  {
  	switch(algo) {
  		case LDNS_SHA1:
  #if defined(HAVE_EVP_SHA1) && defined(USE_SHA1)
  			return SHA_DIGEST_LENGTH;
  #else
  			if(fake_sha1) return 20;
  			return 0;
  #endif
  #ifdef HAVE_EVP_SHA256
  		case LDNS_SHA256:
  			return SHA256_DIGEST_LENGTH;
  #endif
  #ifdef USE_GOST
  		case LDNS_HASH_GOST:
  			/* we support GOST if it can be loaded */
  			(void)sldns_key_EVP_load_gost_id();
  			if(EVP_get_digestbyname("md_gost94"))
  				return 32;
  			else	return 0;
  #endif
  #ifdef USE_ECDSA
  		case LDNS_SHA384:
  			return SHA384_DIGEST_LENGTH;
  #endif
  		default: break;
  	}
  	return 0;
  }
  
  #ifdef USE_GOST
  /** Perform GOST hash */
  static int
  do_gost94(unsigned char* data, size_t len, unsigned char* dest)
  {
  	const EVP_MD* md = EVP_get_digestbyname("md_gost94");
  	if(!md) 
  		return 0;
  	return sldns_digest_evp(data, (unsigned int)len, dest, md);
  }
  #endif
  
  int
  secalgo_ds_digest(int algo, unsigned char* buf, size_t len,
  	unsigned char* res)
  {
  	switch(algo) {
  #if defined(HAVE_EVP_SHA1) && defined(USE_SHA1)
  		case LDNS_SHA1:
  #ifdef OPENSSL_FIPS
  			if(!sldns_digest_evp(buf, len, res, EVP_sha1()))
  				log_crypto_error("could not digest with EVP_sha1",
  					ERR_get_error());
  #else
  			(void)SHA1(buf, len, res);
  #endif
  			return 1;
  #endif
  #ifdef HAVE_EVP_SHA256
  		case LDNS_SHA256:
  #ifdef OPENSSL_FIPS
  			if(!sldns_digest_evp(buf, len, res, EVP_sha256()))
  				log_crypto_error("could not digest with EVP_sha256",
  					ERR_get_error());
  #else
  			(void)SHA256(buf, len, res);
  #endif
  			return 1;
  #endif
  #ifdef USE_GOST
  		case LDNS_HASH_GOST:
  			if(do_gost94(buf, len, res))
  				return 1;
  			break;
  #endif
  #ifdef USE_ECDSA
  		case LDNS_SHA384:
  #ifdef OPENSSL_FIPS
  			if(!sldns_digest_evp(buf, len, res, EVP_sha384()))
  				log_crypto_error("could not digest with EVP_sha384",
  					ERR_get_error());
  #else
  			(void)SHA384(buf, len, res);
  #endif
  			return 1;
  #endif
  		default: 
  			verbose(VERB_QUERY, "unknown DS digest algorithm %d", 
  				algo);
  			break;
  	}
  	return 0;
  }
  
  /** return true if DNSKEY algorithm id is supported */
  int
  dnskey_algo_id_is_supported(int id)
  {
  	switch(id) {
  	case LDNS_RSAMD5:
  		/* RFC 6725 deprecates RSAMD5 */
  		return 0;
  	case LDNS_DSA:
  	case LDNS_DSA_NSEC3:
  #if defined(USE_DSA) && defined(USE_SHA1)
  		return 1;
  #else
  		if(fake_dsa || fake_sha1) return 1;
  		return 0;
  #endif
  
  	case LDNS_RSASHA1:
  	case LDNS_RSASHA1_NSEC3:
  #ifdef USE_SHA1
  		return 1;
  #else
  		if(fake_sha1) return 1;
  		return 0;
  #endif
  
  #if defined(HAVE_EVP_SHA256) && defined(USE_SHA2)
  	case LDNS_RSASHA256:
  #endif
  #if defined(HAVE_EVP_SHA512) && defined(USE_SHA2)
  	case LDNS_RSASHA512:
  #endif
  #ifdef USE_ECDSA
  	case LDNS_ECDSAP256SHA256:
  	case LDNS_ECDSAP384SHA384:
  #endif
  #ifdef USE_ED25519
  	case LDNS_ED25519:
  #endif
  #ifdef USE_ED448
  	case LDNS_ED448:
  #endif
  #if (defined(HAVE_EVP_SHA256) && defined(USE_SHA2)) || (defined(HAVE_EVP_SHA512) && defined(USE_SHA2)) || defined(USE_ECDSA) || defined(USE_ED25519) || defined(USE_ED448)
  		return 1;
  #endif
  
  #ifdef USE_GOST
  	case LDNS_ECC_GOST:
  		/* we support GOST if it can be loaded */
  		return sldns_key_EVP_load_gost_id();
  #endif
  	default:
  		return 0;
  	}
  }
  
  #ifdef USE_DSA
  /**
   * Setup DSA key digest in DER encoding ... 
   * @param sig: input is signature output alloced ptr (unless failure).
   * 	caller must free alloced ptr if this routine returns true.
   * @param len: input is initial siglen, output is output len.
   * @return false on failure.
   */
  static int
  setup_dsa_sig(unsigned char** sig, unsigned int* len)
  {
  	unsigned char* orig = *sig;
  	unsigned int origlen = *len;
  	int newlen;
  	BIGNUM *R, *S;
  	DSA_SIG *dsasig;
  
  	/* extract the R and S field from the sig buffer */
  	if(origlen < 1 + 2*SHA_DIGEST_LENGTH)
  		return 0;
  	R = BN_new();
  	if(!R) return 0;
  	(void) BN_bin2bn(orig + 1, SHA_DIGEST_LENGTH, R);
  	S = BN_new();
  	if(!S) return 0;
  	(void) BN_bin2bn(orig + 21, SHA_DIGEST_LENGTH, S);
  	dsasig = DSA_SIG_new();
  	if(!dsasig) return 0;
  
  #ifdef HAVE_DSA_SIG_SET0
  	if(!DSA_SIG_set0(dsasig, R, S)) return 0;
  #else
  	dsasig->r = R;
  	dsasig->s = S;
  #endif
  	*sig = NULL;
  	newlen = i2d_DSA_SIG(dsasig, sig);
  	if(newlen < 0) {
  		DSA_SIG_free(dsasig);
  		free(*sig);
  		return 0;
  	}
  	*len = (unsigned int)newlen;
  	DSA_SIG_free(dsasig);
  	return 1;
  }
  #endif /* USE_DSA */
  
  #ifdef USE_ECDSA
  /**
   * Setup the ECDSA signature in its encoding that the library wants.
   * Converts from plain numbers to ASN formatted.
   * @param sig: input is signature, output alloced ptr (unless failure).
   * 	caller must free alloced ptr if this routine returns true.
   * @param len: input is initial siglen, output is output len.
   * @return false on failure.
   */
  static int
  setup_ecdsa_sig(unsigned char** sig, unsigned int* len)
  {
          /* convert from two BIGNUMs in the rdata buffer, to ASN notation.
  	 * ASN preamble: 30440220 <R 32bytefor256> 0220 <S 32bytefor256>
  	 * the '20' is the length of that field (=bnsize).
  i	 * the '44' is the total remaining length.
  	 * if negative, start with leading zero.
  	 * if starts with 00s, remove them from the number.
  	 */
          uint8_t pre[] = {0x30, 0x44, 0x02, 0x20};
          int pre_len = 4;
          uint8_t mid[] = {0x02, 0x20};
          int mid_len = 2;
          int raw_sig_len, r_high, s_high, r_rem=0, s_rem=0;
  	int bnsize = (int)((*len)/2);
          unsigned char* d = *sig;
  	uint8_t* p;
  	/* if too short or not even length, fails */
  	if(*len < 16 || bnsize*2 != (int)*len)
  		return 0;
  
          /* strip leading zeroes from r (but not last one) */
          while(r_rem < bnsize-1 && d[r_rem] == 0)
                  r_rem++;
          /* strip leading zeroes from s (but not last one) */
          while(s_rem < bnsize-1 && d[bnsize+s_rem] == 0)
                  s_rem++;
  
          r_high = ((d[0+r_rem]&0x80)?1:0);
          s_high = ((d[bnsize+s_rem]&0x80)?1:0);
          raw_sig_len = pre_len + r_high + bnsize - r_rem + mid_len +
                  s_high + bnsize - s_rem;
  	*sig = (unsigned char*)malloc((size_t)raw_sig_len);
  	if(!*sig)
  		return 0;
  	p = (uint8_t*)*sig;
  	p[0] = pre[0];
  	p[1] = (uint8_t)(raw_sig_len-2);
  	p[2] = pre[2];
  	p[3] = (uint8_t)(bnsize + r_high - r_rem);
  	p += 4;
  	if(r_high) {
  		*p = 0;
  		p += 1;
  	}
  	memmove(p, d+r_rem, (size_t)bnsize-r_rem);
  	p += bnsize-r_rem;
  	memmove(p, mid, (size_t)mid_len-1);
  	p += mid_len-1;
  	*p = (uint8_t)(bnsize + s_high - s_rem);
  	p += 1;
          if(s_high) {
  		*p = 0;
  		p += 1;
  	}
  	memmove(p, d+bnsize+s_rem, (size_t)bnsize-s_rem);
  	*len = (unsigned int)raw_sig_len;
  	return 1;
  }
  #endif /* USE_ECDSA */
  
  #ifdef USE_ECDSA_EVP_WORKAROUND
  static EVP_MD ecdsa_evp_256_md;
  static EVP_MD ecdsa_evp_384_md;
  void ecdsa_evp_workaround_init(void)
  {
  	/* openssl before 1.0.0 fixes RSA with the SHA256
  	 * hash in EVP.  We create one for ecdsa_sha256 */
  	ecdsa_evp_256_md = *EVP_sha256();
  	ecdsa_evp_256_md.required_pkey_type[0] = EVP_PKEY_EC;
  	ecdsa_evp_256_md.verify = (void*)ECDSA_verify;
  
  	ecdsa_evp_384_md = *EVP_sha384();
  	ecdsa_evp_384_md.required_pkey_type[0] = EVP_PKEY_EC;
  	ecdsa_evp_384_md.verify = (void*)ECDSA_verify;
  }
  #endif /* USE_ECDSA_EVP_WORKAROUND */
  
  /**
   * Setup key and digest for verification. Adjust sig if necessary.
   *
   * @param algo: key algorithm
   * @param evp_key: EVP PKEY public key to create.
   * @param digest_type: digest type to use
   * @param key: key to setup for.
   * @param keylen: length of key.
   * @return false on failure.
   */
  static int
  setup_key_digest(int algo, EVP_PKEY** evp_key, const EVP_MD** digest_type, 
  	unsigned char* key, size_t keylen)
  {
  #if defined(USE_DSA) && defined(USE_SHA1)
  	DSA* dsa;
  #endif
  	RSA* rsa;
  
  	switch(algo) {
  #if defined(USE_DSA) && defined(USE_SHA1)
  		case LDNS_DSA:
  		case LDNS_DSA_NSEC3:
  			*evp_key = EVP_PKEY_new();
  			if(!*evp_key) {
  				log_err("verify: malloc failure in crypto");
  				return 0;
  			}
  			dsa = sldns_key_buf2dsa_raw(key, keylen);
  			if(!dsa) {
  				verbose(VERB_QUERY, "verify: "
  					"sldns_key_buf2dsa_raw failed");
  				return 0;
  			}
  			if(EVP_PKEY_assign_DSA(*evp_key, dsa) == 0) {
  				verbose(VERB_QUERY, "verify: "
  					"EVP_PKEY_assign_DSA failed");
  				return 0;
  			}
  #ifdef HAVE_EVP_DSS1
  			*digest_type = EVP_dss1();
  #else
  			*digest_type = EVP_sha1();
  #endif
  
  			break;
  #endif /* USE_DSA && USE_SHA1 */
  
  #if defined(USE_SHA1) || (defined(HAVE_EVP_SHA256) && defined(USE_SHA2)) || (defined(HAVE_EVP_SHA512) && defined(USE_SHA2))
  #ifdef USE_SHA1
  		case LDNS_RSASHA1:
  		case LDNS_RSASHA1_NSEC3:
  #endif
  #if defined(HAVE_EVP_SHA256) && defined(USE_SHA2)
  		case LDNS_RSASHA256:
  #endif
  #if defined(HAVE_EVP_SHA512) && defined(USE_SHA2)
  		case LDNS_RSASHA512:
  #endif
  			*evp_key = EVP_PKEY_new();
  			if(!*evp_key) {
  				log_err("verify: malloc failure in crypto");
  				return 0;
  			}
  			rsa = sldns_key_buf2rsa_raw(key, keylen);
  			if(!rsa) {
  				verbose(VERB_QUERY, "verify: "
  					"sldns_key_buf2rsa_raw SHA failed");
  				return 0;
  			}
  			if(EVP_PKEY_assign_RSA(*evp_key, rsa) == 0) {
  				verbose(VERB_QUERY, "verify: "
  					"EVP_PKEY_assign_RSA SHA failed");
  				return 0;
  			}
  
  			/* select SHA version */
  #if defined(HAVE_EVP_SHA256) && defined(USE_SHA2)
  			if(algo == LDNS_RSASHA256)
  				*digest_type = EVP_sha256();
  			else
  #endif
  #if defined(HAVE_EVP_SHA512) && defined(USE_SHA2)
  				if(algo == LDNS_RSASHA512)
  				*digest_type = EVP_sha512();
  			else
  #endif
  #ifdef USE_SHA1
  				*digest_type = EVP_sha1();
  #else
  				{ verbose(VERB_QUERY, "no digest available"); return 0; }
  #endif
  			break;
  #endif /* defined(USE_SHA1) || (defined(HAVE_EVP_SHA256) && defined(USE_SHA2)) || (defined(HAVE_EVP_SHA512) && defined(USE_SHA2)) */
  
  		case LDNS_RSAMD5:
  			*evp_key = EVP_PKEY_new();
  			if(!*evp_key) {
  				log_err("verify: malloc failure in crypto");
  				return 0;
  			}
  			rsa = sldns_key_buf2rsa_raw(key, keylen);
  			if(!rsa) {
  				verbose(VERB_QUERY, "verify: "
  					"sldns_key_buf2rsa_raw MD5 failed");
  				return 0;
  			}
  			if(EVP_PKEY_assign_RSA(*evp_key, rsa) == 0) {
  				verbose(VERB_QUERY, "verify: "
  					"EVP_PKEY_assign_RSA MD5 failed");
  				return 0;
  			}
  			*digest_type = EVP_md5();
  
  			break;
  #ifdef USE_GOST
  		case LDNS_ECC_GOST:
  			*evp_key = sldns_gost2pkey_raw(key, keylen);
  			if(!*evp_key) {
  				verbose(VERB_QUERY, "verify: "
  					"sldns_gost2pkey_raw failed");
  				return 0;
  			}
  			*digest_type = EVP_get_digestbyname("md_gost94");
  			if(!*digest_type) {
  				verbose(VERB_QUERY, "verify: "
  					"EVP_getdigest md_gost94 failed");
  				return 0;
  			}
  			break;
  #endif
  #ifdef USE_ECDSA
  		case LDNS_ECDSAP256SHA256:
  			*evp_key = sldns_ecdsa2pkey_raw(key, keylen,
  				LDNS_ECDSAP256SHA256);
  			if(!*evp_key) {
  				verbose(VERB_QUERY, "verify: "
  					"sldns_ecdsa2pkey_raw failed");
  				return 0;
  			}
  #ifdef USE_ECDSA_EVP_WORKAROUND
  			*digest_type = &ecdsa_evp_256_md;
  #else
  			*digest_type = EVP_sha256();
  #endif
  			break;
  		case LDNS_ECDSAP384SHA384:
  			*evp_key = sldns_ecdsa2pkey_raw(key, keylen,
  				LDNS_ECDSAP384SHA384);
  			if(!*evp_key) {
  				verbose(VERB_QUERY, "verify: "
  					"sldns_ecdsa2pkey_raw failed");
  				return 0;
  			}
  #ifdef USE_ECDSA_EVP_WORKAROUND
  			*digest_type = &ecdsa_evp_384_md;
  #else
  			*digest_type = EVP_sha384();
  #endif
  			break;
  #endif /* USE_ECDSA */
  #ifdef USE_ED25519
  		case LDNS_ED25519:
  			*evp_key = sldns_ed255192pkey_raw(key, keylen);
  			if(!*evp_key) {
  				verbose(VERB_QUERY, "verify: "
  					"sldns_ed255192pkey_raw failed");
  				return 0;
  			}
  			*digest_type = NULL;
  			break;
  #endif /* USE_ED25519 */
  #ifdef USE_ED448
  		case LDNS_ED448:
  			*evp_key = sldns_ed4482pkey_raw(key, keylen);
  			if(!*evp_key) {
  				verbose(VERB_QUERY, "verify: "
  					"sldns_ed4482pkey_raw failed");
  				return 0;
  			}
  			*digest_type = NULL;
  			break;
  #endif /* USE_ED448 */
  		default:
  			verbose(VERB_QUERY, "verify: unknown algorithm %d", 
  				algo);
  			return 0;
  	}
  	return 1;
  }
  
  /**
   * Check a canonical sig+rrset and signature against a dnskey
   * @param buf: buffer with data to verify, the first rrsig part and the
   *	canonicalized rrset.
   * @param algo: DNSKEY algorithm.
   * @param sigblock: signature rdata field from RRSIG
   * @param sigblock_len: length of sigblock data.
   * @param key: public key data from DNSKEY RR.
   * @param keylen: length of keydata.
   * @param reason: bogus reason in more detail.
   * @return secure if verification succeeded, bogus on crypto failure,
   *	unchecked on format errors and alloc failures.
   */
  enum sec_status
  verify_canonrrset(sldns_buffer* buf, int algo, unsigned char* sigblock, 
  	unsigned int sigblock_len, unsigned char* key, unsigned int keylen,
  	char** reason)
  {
  	const EVP_MD *digest_type;
  	EVP_MD_CTX* ctx;
  	int res, dofree = 0, docrypto_free = 0;
  	EVP_PKEY *evp_key = NULL;
  
  #ifndef USE_DSA
  	if((algo == LDNS_DSA || algo == LDNS_DSA_NSEC3) &&(fake_dsa||fake_sha1))
  		return sec_status_secure;
  #endif
  #ifndef USE_SHA1
  	if(fake_sha1 && (algo == LDNS_DSA || algo == LDNS_DSA_NSEC3 || algo == LDNS_RSASHA1 || algo == LDNS_RSASHA1_NSEC3))
  		return sec_status_secure;
  #endif
  	
  	if(!setup_key_digest(algo, &evp_key, &digest_type, key, keylen)) {
  		verbose(VERB_QUERY, "verify: failed to setup key");
  		*reason = "use of key for crypto failed";
  		EVP_PKEY_free(evp_key);
  		return sec_status_bogus;
  	}
  #ifdef USE_DSA
  	/* if it is a DSA signature in bind format, convert to DER format */
  	if((algo == LDNS_DSA || algo == LDNS_DSA_NSEC3) && 
  		sigblock_len == 1+2*SHA_DIGEST_LENGTH) {
  		if(!setup_dsa_sig(&sigblock, &sigblock_len)) {
  			verbose(VERB_QUERY, "verify: failed to setup DSA sig");
  			*reason = "use of key for DSA crypto failed";
  			EVP_PKEY_free(evp_key);
  			return sec_status_bogus;
  		}
  		docrypto_free = 1;
  	}
  #endif
  #if defined(USE_ECDSA) && defined(USE_DSA)
  	else 
  #endif
  #ifdef USE_ECDSA
  	if(algo == LDNS_ECDSAP256SHA256 || algo == LDNS_ECDSAP384SHA384) {
  		/* EVP uses ASN prefix on sig, which is not in the wire data */
  		if(!setup_ecdsa_sig(&sigblock, &sigblock_len)) {
  			verbose(VERB_QUERY, "verify: failed to setup ECDSA sig");
  			*reason = "use of signature for ECDSA crypto failed";
  			EVP_PKEY_free(evp_key);
  			return sec_status_bogus;
  		}
  		dofree = 1;
  	}
  #endif /* USE_ECDSA */
  
  	/* do the signature cryptography work */
  #ifdef HAVE_EVP_MD_CTX_NEW
  	ctx = EVP_MD_CTX_new();
  #else
  	ctx = (EVP_MD_CTX*)malloc(sizeof(*ctx));
  	if(ctx) EVP_MD_CTX_init(ctx);
  #endif
  	if(!ctx) {
  		log_err("EVP_MD_CTX_new: malloc failure");
  		EVP_PKEY_free(evp_key);
  		if(dofree) free(sigblock);
  		else if(docrypto_free) OPENSSL_free(sigblock);
  		return sec_status_unchecked;
  	}
  #ifndef HAVE_EVP_DIGESTVERIFY
  	if(EVP_DigestInit(ctx, digest_type) == 0) {
  		verbose(VERB_QUERY, "verify: EVP_DigestInit failed");
  #ifdef HAVE_EVP_MD_CTX_NEW
  		EVP_MD_CTX_destroy(ctx);
  #else
  		EVP_MD_CTX_cleanup(ctx);
  		free(ctx);
  #endif
  		EVP_PKEY_free(evp_key);
  		if(dofree) free(sigblock);
  		else if(docrypto_free) OPENSSL_free(sigblock);
  		return sec_status_unchecked;
  	}
  	if(EVP_DigestUpdate(ctx, (unsigned char*)sldns_buffer_begin(buf), 
  		(unsigned int)sldns_buffer_limit(buf)) == 0) {
  		verbose(VERB_QUERY, "verify: EVP_DigestUpdate failed");
  #ifdef HAVE_EVP_MD_CTX_NEW
  		EVP_MD_CTX_destroy(ctx);
  #else
  		EVP_MD_CTX_cleanup(ctx);
  		free(ctx);
  #endif
  		EVP_PKEY_free(evp_key);
  		if(dofree) free(sigblock);
  		else if(docrypto_free) OPENSSL_free(sigblock);
  		return sec_status_unchecked;
  	}
  
  	res = EVP_VerifyFinal(ctx, sigblock, sigblock_len, evp_key);
  #else /* HAVE_EVP_DIGESTVERIFY */
  	if(EVP_DigestVerifyInit(ctx, NULL, digest_type, NULL, evp_key) == 0) {
  		verbose(VERB_QUERY, "verify: EVP_DigestVerifyInit failed");
  #ifdef HAVE_EVP_MD_CTX_NEW
  		EVP_MD_CTX_destroy(ctx);
  #else
  		EVP_MD_CTX_cleanup(ctx);
  		free(ctx);
  #endif
  		EVP_PKEY_free(evp_key);
  		if(dofree) free(sigblock);
  		else if(docrypto_free) OPENSSL_free(sigblock);
  		return sec_status_unchecked;
  	}
  	res = EVP_DigestVerify(ctx, sigblock, sigblock_len,
  		(unsigned char*)sldns_buffer_begin(buf),
  		sldns_buffer_limit(buf));
  #endif
  #ifdef HAVE_EVP_MD_CTX_NEW
  	EVP_MD_CTX_destroy(ctx);
  #else
  	EVP_MD_CTX_cleanup(ctx);
  	free(ctx);
  #endif
  	EVP_PKEY_free(evp_key);
  
  	if(dofree) free(sigblock);
  	else if(docrypto_free) OPENSSL_free(sigblock);
  
  	if(res == 1) {
  		return sec_status_secure;
  	} else if(res == 0) {
  		verbose(VERB_QUERY, "verify: signature mismatch");
  		*reason = "signature crypto failed";
  		return sec_status_bogus;
  	}
  
  	log_crypto_error("verify:", ERR_get_error());
  	return sec_status_unchecked;
  }
  
  /**************************************************/
  #elif defined(HAVE_NSS)
  /* libnss implementation */
  /* nss3 */
  #include "sechash.h"
  #include "pk11pub.h"
  #include "keyhi.h"
  #include "secerr.h"
  #include "cryptohi.h"
  /* nspr4 */
  #include "prerror.h"
  
  /* return size of digest if supported, or 0 otherwise */
  size_t
  nsec3_hash_algo_size_supported(int id)
  {
  	switch(id) {
  	case NSEC3_HASH_SHA1:
  		return SHA1_LENGTH;
  	default:
  		return 0;
  	}
  }
  
  /* perform nsec3 hash. return false on failure */
  int
  secalgo_nsec3_hash(int algo, unsigned char* buf, size_t len,
          unsigned char* res)
  {
  	switch(algo) {
  	case NSEC3_HASH_SHA1:
  		(void)HASH_HashBuf(HASH_AlgSHA1, res, buf, (unsigned long)len);
  		return 1;
  	default:
  		return 0;
  	}
  }
  
  void
  secalgo_hash_sha256(unsigned char* buf, size_t len, unsigned char* res)
  {
  	(void)HASH_HashBuf(HASH_AlgSHA256, res, buf, (unsigned long)len);
  }
  
  size_t
  ds_digest_size_supported(int algo)
  {
  	/* uses libNSS */
  	switch(algo) {
  #ifdef USE_SHA1
  		case LDNS_SHA1:
  			return SHA1_LENGTH;
  #endif
  #ifdef USE_SHA2
  		case LDNS_SHA256:
  			return SHA256_LENGTH;
  #endif
  #ifdef USE_ECDSA
  		case LDNS_SHA384:
  			return SHA384_LENGTH;
  #endif
  		/* GOST not supported in NSS */
  		case LDNS_HASH_GOST:
  		default: break;
  	}
  	return 0;
  }
  
  int
  secalgo_ds_digest(int algo, unsigned char* buf, size_t len,
  	unsigned char* res)
  {
  	/* uses libNSS */
  	switch(algo) {
  #ifdef USE_SHA1
  		case LDNS_SHA1:
  			return HASH_HashBuf(HASH_AlgSHA1, res, buf, len)
  				== SECSuccess;
  #endif
  #if defined(USE_SHA2)
  		case LDNS_SHA256:
  			return HASH_HashBuf(HASH_AlgSHA256, res, buf, len)
  				== SECSuccess;
  #endif
  #ifdef USE_ECDSA
  		case LDNS_SHA384:
  			return HASH_HashBuf(HASH_AlgSHA384, res, buf, len)
  				== SECSuccess;
  #endif
  		case LDNS_HASH_GOST:
  		default: 
  			verbose(VERB_QUERY, "unknown DS digest algorithm %d", 
  				algo);
  			break;
  	}
  	return 0;
  }
  
  int
  dnskey_algo_id_is_supported(int id)
  {
  	/* uses libNSS */
  	switch(id) {
  	case LDNS_RSAMD5:
  		/* RFC 6725 deprecates RSAMD5 */
  		return 0;
  #if defined(USE_SHA1) || defined(USE_SHA2)
  #if defined(USE_DSA) && defined(USE_SHA1)
  	case LDNS_DSA:
  	case LDNS_DSA_NSEC3:
  #endif
  #ifdef USE_SHA1
  	case LDNS_RSASHA1:
  	case LDNS_RSASHA1_NSEC3:
  #endif
  #ifdef USE_SHA2
  	case LDNS_RSASHA256:
  #endif
  #ifdef USE_SHA2
  	case LDNS_RSASHA512:
  #endif
  		return 1;
  #endif /* SHA1 or SHA2 */
  
  #ifdef USE_ECDSA
  	case LDNS_ECDSAP256SHA256:
  	case LDNS_ECDSAP384SHA384:
  		return PK11_TokenExists(CKM_ECDSA);
  #endif
  	case LDNS_ECC_GOST:
  	default:
  		return 0;
  	}
  }
  
  /* return a new public key for NSS */
  static SECKEYPublicKey* nss_key_create(KeyType ktype)
  {
  	SECKEYPublicKey* key;
  	PLArenaPool* arena = PORT_NewArena(DER_DEFAULT_CHUNKSIZE);
  	if(!arena) {
  		log_err("out of memory, PORT_NewArena failed");
  		return NULL;
  	}
  	key = PORT_ArenaZNew(arena, SECKEYPublicKey);
  	if(!key) {
  		log_err("out of memory, PORT_ArenaZNew failed");
  		PORT_FreeArena(arena, PR_FALSE);
  		return NULL;
  	}
  	key->arena = arena;
  	key->keyType = ktype;
  	key->pkcs11Slot = NULL;
  	key->pkcs11ID = CK_INVALID_HANDLE;
  	return key;
  }
  
  static SECKEYPublicKey* nss_buf2ecdsa(unsigned char* key, size_t len, int algo)
  {
  	SECKEYPublicKey* pk;
  	SECItem pub = {siBuffer, NULL, 0};
  	SECItem params = {siBuffer, NULL, 0};
  	static unsigned char param256[] = {
  		/* OBJECTIDENTIFIER 1.2.840.10045.3.1.7 (P-256)
  		 * {iso(1) member-body(2) us(840) ansi-x962(10045) curves(3) prime(1) prime256v1(7)} */
  		0x06, 0x08, 0x2a, 0x86, 0x48, 0xce, 0x3d, 0x03, 0x01, 0x07
  	};
  	static unsigned char param384[] = {
  		/* OBJECTIDENTIFIER 1.3.132.0.34 (P-384)
  		 * {iso(1) identified-organization(3) certicom(132) curve(0) ansip384r1(34)} */
  		0x06, 0x05, 0x2b, 0x81, 0x04, 0x00, 0x22
  	};
  	unsigned char buf[256+2]; /* sufficient for 2*384/8+1 */
  
  	/* check length, which uncompressed must be 2 bignums */
  	if(algo == LDNS_ECDSAP256SHA256) {
  		if(len != 2*256/8) return NULL;
  		/* ECCurve_X9_62_PRIME_256V1 */
  	} else if(algo == LDNS_ECDSAP384SHA384) {
  		if(len != 2*384/8) return NULL;
  		/* ECCurve_X9_62_PRIME_384R1 */
  	} else    return NULL;
  
  	buf[0] = 0x04; /* POINT_FORM_UNCOMPRESSED */
  	memmove(buf+1, key, len);
  	pub.data = buf;
  	pub.len = len+1;
  	if(algo == LDNS_ECDSAP256SHA256) {
  		params.data = param256;
  		params.len = sizeof(param256);
  	} else {
  		params.data = param384;
  		params.len = sizeof(param384);
  	}
  
  	pk = nss_key_create(ecKey);
  	if(!pk)
  		return NULL;
  	pk->u.ec.size = (len/2)*8;
  	if(SECITEM_CopyItem(pk->arena, &pk->u.ec.publicValue, &pub)) {
  		SECKEY_DestroyPublicKey(pk);
  		return NULL;
  	}
  	if(SECITEM_CopyItem(pk->arena, &pk->u.ec.DEREncodedParams, &params)) {
  		SECKEY_DestroyPublicKey(pk);
  		return NULL;
  	}
  
  	return pk;
  }
  
  static SECKEYPublicKey* nss_buf2dsa(unsigned char* key, size_t len)
  {
  	SECKEYPublicKey* pk;
  	uint8_t T;
  	uint16_t length;
  	uint16_t offset;
  	SECItem Q = {siBuffer, NULL, 0};
  	SECItem P = {siBuffer, NULL, 0};
  	SECItem G = {siBuffer, NULL, 0};
  	SECItem Y = {siBuffer, NULL, 0};
  
  	if(len == 0)
  		return NULL;
  	T = (uint8_t)key[0];
  	length = (64 + T * 8);
  	offset = 1;
  
  	if (T > 8) {
  		return NULL;
  	}
  	if(len < (size_t)1 + SHA1_LENGTH + 3*length)
  		return NULL;
  
  	Q.data = key+offset;
  	Q.len = SHA1_LENGTH;
  	offset += SHA1_LENGTH;
  
  	P.data = key+offset;
  	P.len = length;
  	offset += length;
  
  	G.data = key+offset;
  	G.len = length;
  	offset += length;
  
  	Y.data = key+offset;
  	Y.len = length;
  	offset += length;
  
  	pk = nss_key_create(dsaKey);
  	if(!pk)
  		return NULL;
  	if(SECITEM_CopyItem(pk->arena, &pk->u.dsa.params.prime, &P)) {
  		SECKEY_DestroyPublicKey(pk);
  		return NULL;
  	}
  	if(SECITEM_CopyItem(pk->arena, &pk->u.dsa.params.subPrime, &Q)) {
  		SECKEY_DestroyPublicKey(pk);
  		return NULL;
  	}
  	if(SECITEM_CopyItem(pk->arena, &pk->u.dsa.params.base, &G)) {
  		SECKEY_DestroyPublicKey(pk);
  		return NULL;
  	}
  	if(SECITEM_CopyItem(pk->arena, &pk->u.dsa.publicValue, &Y)) {
  		SECKEY_DestroyPublicKey(pk);
  		return NULL;
  	}
  	return pk;
  }
  
  static SECKEYPublicKey* nss_buf2rsa(unsigned char* key, size_t len)
  {
  	SECKEYPublicKey* pk;
  	uint16_t exp;
  	uint16_t offset;
  	uint16_t int16;
  	SECItem modulus = {siBuffer, NULL, 0};
  	SECItem exponent = {siBuffer, NULL, 0};
  	if(len == 0)
  		return NULL;
  	if(key[0] == 0) {
  		if(len < 3)
  			return NULL;
  		/* the exponent is too large so it's places further */
  		memmove(&int16, key+1, 2);
  		exp = ntohs(int16);
  		offset = 3;
  	} else {
  		exp = key[0];
  		offset = 1;
  	}
  
  	/* key length at least one */
  	if(len < (size_t)offset + exp + 1)
  		return NULL;
  	
  	exponent.data = key+offset;
  	exponent.len = exp;
  	offset += exp;
  	modulus.data = key+offset;
  	modulus.len = (len - offset);
  
  	pk = nss_key_create(rsaKey);
  	if(!pk)
  		return NULL;
  	if(SECITEM_CopyItem(pk->arena, &pk->u.rsa.modulus, &modulus)) {
  		SECKEY_DestroyPublicKey(pk);
  		return NULL;
  	}
  	if(SECITEM_CopyItem(pk->arena, &pk->u.rsa.publicExponent, &exponent)) {
  		SECKEY_DestroyPublicKey(pk);
  		return NULL;
  	}
  	return pk;
  }
  
  /**
   * Setup key and digest for verification. Adjust sig if necessary.
   *
   * @param algo: key algorithm
   * @param evp_key: EVP PKEY public key to create.
   * @param digest_type: digest type to use
   * @param key: key to setup for.
   * @param keylen: length of key.
   * @param prefix: if returned, the ASN prefix for the hashblob.
   * @param prefixlen: length of the prefix.
   * @return false on failure.
   */
  static int
  nss_setup_key_digest(int algo, SECKEYPublicKey** pubkey, HASH_HashType* htype,
  	unsigned char* key, size_t keylen, unsigned char** prefix,
  	size_t* prefixlen)
  {
  	/* uses libNSS */
  
  	/* hash prefix for md5, RFC2537 */
  	static unsigned char p_md5[] = {0x30, 0x20, 0x30, 0x0c, 0x06, 0x08, 0x2a,
  	0x86, 0x48, 0x86, 0xf7, 0x0d, 0x02, 0x05, 0x05, 0x00, 0x04, 0x10};
  	/* hash prefix to prepend to hash output, from RFC3110 */
  	static unsigned char p_sha1[] = {0x30, 0x21, 0x30, 0x09, 0x06, 0x05, 0x2B,
  		0x0E, 0x03, 0x02, 0x1A, 0x05, 0x00, 0x04, 0x14};
  	/* from RFC5702 */
  	static unsigned char p_sha256[] = {0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60,
  	0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, 0x05, 0x00, 0x04, 0x20};
  	static unsigned char p_sha512[] = {0x30, 0x51, 0x30, 0x0d, 0x06, 0x09, 0x60,
  	0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03, 0x05, 0x00, 0x04, 0x40};
  	/* from RFC6234 */
  	/* for future RSASHA384 .. 
  	static unsigned char p_sha384[] = {0x30, 0x51, 0x30, 0x0d, 0x06, 0x09, 0x60,
  	0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02, 0x05, 0x00, 0x04, 0x30};
  	*/
  
  	switch(algo) {
  
  #if defined(USE_SHA1) || defined(USE_SHA2)
  #if defined(USE_DSA) && defined(USE_SHA1)
  		case LDNS_DSA:
  		case LDNS_DSA_NSEC3:
  			*pubkey = nss_buf2dsa(key, keylen);
  			if(!*pubkey) {
  				log_err("verify: malloc failure in crypto");
  				return 0;
  			}
  			*htype = HASH_AlgSHA1;
  			/* no prefix for DSA verification */
  			break;
  #endif
  #ifdef USE_SHA1
  		case LDNS_RSASHA1:
  		case LDNS_RSASHA1_NSEC3:
  #endif
  #ifdef USE_SHA2
  		case LDNS_RSASHA256:
  #endif
  #ifdef USE_SHA2
  		case LDNS_RSASHA512:
  #endif
  			*pubkey = nss_buf2rsa(key, keylen);
  			if(!*pubkey) {
  				log_err("verify: malloc failure in crypto");
  				return 0;
  			}
  			/* select SHA version */
  #ifdef USE_SHA2
  			if(algo == LDNS_RSASHA256) {
  				*htype = HASH_AlgSHA256;
  				*prefix = p_sha256;
  				*prefixlen = sizeof(p_sha256);
  			} else
  #endif
  #ifdef USE_SHA2
  				if(algo == LDNS_RSASHA512) {
  				*htype = HASH_AlgSHA512;
  				*prefix = p_sha512;
  				*prefixlen = sizeof(p_sha512);
  			} else
  #endif
  #ifdef USE_SHA1
  			{
  				*htype = HASH_AlgSHA1;
  				*prefix = p_sha1;
  				*prefixlen = sizeof(p_sha1);
  			}
  #else
  			{
  				verbose(VERB_QUERY, "verify: no digest algo");
  				return 0;
  			}
  #endif
  
  			break;
  #endif /* SHA1 or SHA2 */
  
  		case LDNS_RSAMD5:
  			*pubkey = nss_buf2rsa(key, keylen);
  			if(!*pubkey) {
  				log_err("verify: malloc failure in crypto");
  				return 0;
  			}
  			*htype = HASH_AlgMD5;
  			*prefix = p_md5;
  			*prefixlen = sizeof(p_md5);
  
  			break;
  #ifdef USE_ECDSA
  		case LDNS_ECDSAP256SHA256:
  			*pubkey = nss_buf2ecdsa(key, keylen,
  				LDNS_ECDSAP256SHA256);
  			if(!*pubkey) {
  				log_err("verify: malloc failure in crypto");
  				return 0;
  			}
  			*htype = HASH_AlgSHA256;
  			/* no prefix for DSA verification */
  			break;
  		case LDNS_ECDSAP384SHA384:
  			*pubkey = nss_buf2ecdsa(key, keylen,
  				LDNS_ECDSAP384SHA384);
  			if(!*pubkey) {
  				log_err("verify: malloc failure in crypto");
  				return 0;
  			}
  			*htype = HASH_AlgSHA384;
  			/* no prefix for DSA verification */
  			break;
  #endif /* USE_ECDSA */
  		case LDNS_ECC_GOST:
  		default:
  			verbose(VERB_QUERY, "verify: unknown algorithm %d", 
  				algo);
  			return 0;
  	}
  	return 1;
  }
  
  /**
   * Check a canonical sig+rrset and signature against a dnskey
   * @param buf: buffer with data to verify, the first rrsig part and the
   *	canonicalized rrset.
   * @param algo: DNSKEY algorithm.
   * @param sigblock: signature rdata field from RRSIG
   * @param sigblock_len: length of sigblock data.
   * @param key: public key data from DNSKEY RR.
   * @param keylen: length of keydata.
   * @param reason: bogus reason in more detail.
   * @return secure if verification succeeded, bogus on crypto failure,
   *	unchecked on format errors and alloc failures.
   */
  enum sec_status
  verify_canonrrset(sldns_buffer* buf, int algo, unsigned char* sigblock, 
  	unsigned int sigblock_len, unsigned char* key, unsigned int keylen,
  	char** reason)
  {
  	/* uses libNSS */
  	/* large enough for the different hashes */
  	unsigned char hash[HASH_LENGTH_MAX];
  	unsigned char hash2[HASH_LENGTH_MAX*2];
  	HASH_HashType htype = 0;
  	SECKEYPublicKey* pubkey = NULL;
  	SECItem secsig = {siBuffer, sigblock, sigblock_len};
  	SECItem sechash = {siBuffer, hash, 0};
  	SECStatus res;
  	unsigned char* prefix = NULL; /* prefix for hash, RFC3110, RFC5702 */
  	size_t prefixlen = 0;
  	int err;
  
  	if(!nss_setup_key_digest(algo, &pubkey, &htype, key, keylen,
  		&prefix, &prefixlen)) {
  		verbose(VERB_QUERY, "verify: failed to setup key");
  		*reason = "use of key for crypto failed";
  		SECKEY_DestroyPublicKey(pubkey);
  		return sec_status_bogus;
  	}
  
  #if defined(USE_DSA) && defined(USE_SHA1)
  	/* need to convert DSA, ECDSA signatures? */
  	if((algo == LDNS_DSA || algo == LDNS_DSA_NSEC3)) {
  		if(sigblock_len == 1+2*SHA1_LENGTH) {
  			secsig.data ++;
  			secsig.len --;
  		} else {
  			SECItem* p = DSAU_DecodeDerSig(&secsig);
  			if(!p) {
  				verbose(VERB_QUERY, "verify: failed DER decode");
  				*reason = "signature DER decode failed";
  				SECKEY_DestroyPublicKey(pubkey);
  				return sec_status_bogus;
  			}
  			if(SECITEM_CopyItem(pubkey->arena, &secsig, p)) {
  				log_err("alloc failure in DER decode");
  				SECKEY_DestroyPublicKey(pubkey);
  				SECITEM_FreeItem(p, PR_TRUE);
  				return sec_status_unchecked;
  			}
  			SECITEM_FreeItem(p, PR_TRUE);
  		}
  	}
  #endif /* USE_DSA */
  
  	/* do the signature cryptography work */
  	/* hash the data */
  	sechash.len = HASH_ResultLen(htype);
  	if(sechash.len > sizeof(hash)) {
  		verbose(VERB_QUERY, "verify: hash too large for buffer");
  		SECKEY_DestroyPublicKey(pubkey);
  		return sec_status_unchecked;
  	}
  	if(HASH_HashBuf(htype, hash, (unsigned char*)sldns_buffer_begin(buf),
  		(unsigned int)sldns_buffer_limit(buf)) != SECSuccess) {
  		verbose(VERB_QUERY, "verify: HASH_HashBuf failed");
  		SECKEY_DestroyPublicKey(pubkey);
  		return sec_status_unchecked;
  	}
  	if(prefix) {
  		int hashlen = sechash.len;
  		if(prefixlen+hashlen > sizeof(hash2)) {
  			verbose(VERB_QUERY, "verify: hashprefix too large");
  			SECKEY_DestroyPublicKey(pubkey);
  			return sec_status_unchecked;
  		}
  		sechash.data = hash2;
  		sechash.len = prefixlen+hashlen;
  		memcpy(sechash.data, prefix, prefixlen);
  		memmove(sechash.data+prefixlen, hash, hashlen);
  	}
  
  	/* verify the signature */
  	res = PK11_Verify(pubkey, &secsig, &sechash, NULL /*wincx*/);
  	SECKEY_DestroyPublicKey(pubkey);
  
  	if(res == SECSuccess) {
  		return sec_status_secure;
  	}
  	err = PORT_GetError();
  	if(err != SEC_ERROR_BAD_SIGNATURE) {
  		/* failed to verify */
  		verbose(VERB_QUERY, "verify: PK11_Verify failed: %s",
  			PORT_ErrorToString(err));
  		/* if it is not supported, like ECC is removed, we get,
  		 * SEC_ERROR_NO_MODULE */
  		if(err == SEC_ERROR_NO_MODULE)
  			return sec_status_unchecked;
  		/* but other errors are commonly returned
  		 * for a bad signature from NSS.  Thus we return bogus,
  		 * not unchecked */
  		*reason = "signature crypto failed";
  		return sec_status_bogus;
  	}
  	verbose(VERB_QUERY, "verify: signature mismatch: %s",
  		PORT_ErrorToString(err));
  	*reason = "signature crypto failed";
  	return sec_status_bogus;
  }
  
  #elif defined(HAVE_NETTLE)
  
  #include "sha.h"
  #include "bignum.h"
  #include "macros.h"
  #include "rsa.h"
  #include "dsa.h"
  #ifdef HAVE_NETTLE_DSA_COMPAT_H
  #include "dsa-compat.h"
  #endif
  #include "asn1.h"
  #ifdef USE_ECDSA
  #include "ecdsa.h"
  #include "ecc-curve.h"
  #endif
  #ifdef HAVE_NETTLE_EDDSA_H
  #include "eddsa.h"
  #endif
  
  static int
  _digest_nettle(int algo, uint8_t* buf, size_t len,
  	unsigned char* res)
  {
  	switch(algo) {
  		case SHA1_DIGEST_SIZE:
  		{
  			struct sha1_ctx ctx;
  			sha1_init(&ctx);
  			sha1_update(&ctx, len, buf);
  			sha1_digest(&ctx, SHA1_DIGEST_SIZE, res);
  			return 1;
  		}
  		case SHA256_DIGEST_SIZE:
  		{
  			struct sha256_ctx ctx;
  			sha256_init(&ctx);
  			sha256_update(&ctx, len, buf);
  			sha256_digest(&ctx, SHA256_DIGEST_SIZE, res);
  			return 1;
  		}
  		case SHA384_DIGEST_SIZE:
  		{
  			struct sha384_ctx ctx;
  			sha384_init(&ctx);
  			sha384_update(&ctx, len, buf);
  			sha384_digest(&ctx, SHA384_DIGEST_SIZE, res);
  			return 1;
  		}
  		case SHA512_DIGEST_SIZE:
  		{
  			struct sha512_ctx ctx;
  			sha512_init(&ctx);
  			sha512_update(&ctx, len, buf);
  			sha512_digest(&ctx, SHA512_DIGEST_SIZE, res);
  			return 1;
  		}
  		default:
  			break;
  	}
  	return 0;
  }
  
  /* return size of digest if supported, or 0 otherwise */
  size_t
  nsec3_hash_algo_size_supported(int id)
  {
  	switch(id) {
  	case NSEC3_HASH_SHA1:
  		return SHA1_DIGEST_SIZE;
  	default:
  		return 0;
  	}
  }
  
  /* perform nsec3 hash. return false on failure */
  int
  secalgo_nsec3_hash(int algo, unsigned char* buf, size_t len,
          unsigned char* res)
  {
  	switch(algo) {
  	case NSEC3_HASH_SHA1:
  		return _digest_nettle(SHA1_DIGEST_SIZE, (uint8_t*)buf, len,
  			res);
  	default:
  		return 0;
  	}
  }
  
  void
  secalgo_hash_sha256(unsigned char* buf, size_t len, unsigned char* res)
  {
  	_digest_nettle(SHA256_DIGEST_SIZE, (uint8_t*)buf, len, res);
  }
  
  /**
   * Return size of DS digest according to its hash algorithm.
   * @param algo: DS digest algo.
   * @return size in bytes of digest, or 0 if not supported.
   */
  size_t
  ds_digest_size_supported(int algo)
  {
  	switch(algo) {
  		case LDNS_SHA1:
  #ifdef USE_SHA1
  			return SHA1_DIGEST_SIZE;
  #else
  			if(fake_sha1) return 20;
  			return 0;
  #endif
  #ifdef USE_SHA2
  		case LDNS_SHA256:
  			return SHA256_DIGEST_SIZE;
  #endif
  #ifdef USE_ECDSA
  		case LDNS_SHA384:
  			return SHA384_DIGEST_SIZE;
  #endif
  		/* GOST not supported */
  		case LDNS_HASH_GOST:
  		default:
  			break;
  	}
  	return 0;
  }
  
  int
  secalgo_ds_digest(int algo, unsigned char* buf, size_t len,
  	unsigned char* res)
  {
  	switch(algo) {
  #ifdef USE_SHA1
  		case LDNS_SHA1:
  			return _digest_nettle(SHA1_DIGEST_SIZE, buf, len, res);
  #endif
  #if defined(USE_SHA2)
  		case LDNS_SHA256:
  			return _digest_nettle(SHA256_DIGEST_SIZE, buf, len, res);
  #endif
  #ifdef USE_ECDSA
  		case LDNS_SHA384:
  			return _digest_nettle(SHA384_DIGEST_SIZE, buf, len, res);
  
  #endif
  		case LDNS_HASH_GOST:
  		default:
  			verbose(VERB_QUERY, "unknown DS digest algorithm %d",
  				algo);
  			break;
  	}
  	return 0;
  }
  
  int
  dnskey_algo_id_is_supported(int id)
  {
  	/* uses libnettle */
  	switch(id) {
  #if defined(USE_DSA) && defined(USE_SHA1)
  	case LDNS_DSA:
  	case LDNS_DSA_NSEC3:
  #endif
  #ifdef USE_SHA1
  	case LDNS_RSASHA1:
  	case LDNS_RSASHA1_NSEC3:
  #endif
  #ifdef USE_SHA2
  	case LDNS_RSASHA256:
  	case LDNS_RSASHA512:
  #endif
  #ifdef USE_ECDSA
  	case LDNS_ECDSAP256SHA256:
  	case LDNS_ECDSAP384SHA384:
  #endif
  		return 1;
  #ifdef USE_ED25519
  	case LDNS_ED25519:
  		return 1;
  #endif
  	case LDNS_RSAMD5: /* RFC 6725 deprecates RSAMD5 */
  	case LDNS_ECC_GOST:
  	default:
  		return 0;
  	}
  }
  
  #if defined(USE_DSA) && defined(USE_SHA1)
  static char *
  _verify_nettle_dsa(sldns_buffer* buf, unsigned char* sigblock,
  	unsigned int sigblock_len, unsigned char* key, unsigned int keylen)
  {
  	uint8_t digest[SHA1_DIGEST_SIZE];
  	uint8_t key_t_value;
  	int res = 0;
  	size_t offset;
  	struct dsa_public_key pubkey;
  	struct dsa_signature signature;
  	unsigned int expected_len;
  
  	/* Extract DSA signature from the record */
  	nettle_dsa_signature_init(&signature);
  	/* Signature length: 41 bytes - RFC 2536 sec. 3 */
  	if(sigblock_len == 41) {
  		if(key[0] != sigblock[0])
  			return "invalid T value in DSA signature or pubkey";
  		nettle_mpz_set_str_256_u(signature.r, 20, sigblock+1);
  		nettle_mpz_set_str_256_u(signature.s, 20, sigblock+1+20);
  	} else {
  		/* DER encoded, decode the ASN1 notated R and S bignums */
  		/* SEQUENCE { r INTEGER, s INTEGER } */
  		struct asn1_der_iterator i, seq;
  		if(asn1_der_iterator_first(&i, sigblock_len,
  			(uint8_t*)sigblock) != ASN1_ITERATOR_CONSTRUCTED
  			|| i.type != ASN1_SEQUENCE)
  			return "malformed DER encoded DSA signature";
  		/* decode this element of i using the seq iterator */
  		if(asn1_der_decode_constructed(&i, &seq) !=
  			ASN1_ITERATOR_PRIMITIVE || seq.type != ASN1_INTEGER)
  			return "malformed DER encoded DSA signature";
  		if(!asn1_der_get_bignum(&seq, signature.r, 20*8))
  			return "malformed DER encoded DSA signature";
  		if(asn1_der_iterator_next(&seq) != ASN1_ITERATOR_PRIMITIVE
  			|| seq.type != ASN1_INTEGER)
  			return "malformed DER encoded DSA signature";
  		if(!asn1_der_get_bignum(&seq, signature.s, 20*8))
  			return "malformed DER encoded DSA signature";
  		if(asn1_der_iterator_next(&i) != ASN1_ITERATOR_END)
  			return "malformed DER encoded DSA signature";
  	}
  
  	/* Validate T values constraints - RFC 2536 sec. 2 & sec. 3 */
  	key_t_value = key[0];
  	if (key_t_value > 8) {
  		return "invalid T value in DSA pubkey";
  	}
  
  	/* Pubkey minimum length: 21 bytes - RFC 2536 sec. 2 */
  	if (keylen < 21) {
  		return "DSA pubkey too short";
  	}
  
  	expected_len =   1 +		/* T */
  		        20 +		/* Q */
  		       (64 + key_t_value*8) +	/* P */
  		       (64 + key_t_value*8) +	/* G */
  		       (64 + key_t_value*8);	/* Y */
  	if (keylen != expected_len ) {
  		return "invalid DSA pubkey length";
  	}
  
  	/* Extract DSA pubkey from the record */
  	nettle_dsa_public_key_init(&pubkey);
  	offset = 1;
  	nettle_mpz_set_str_256_u(pubkey.q, 20, key+offset);
  	offset += 20;
  	nettle_mpz_set_str_256_u(pubkey.p, (64 + key_t_value*8), key+offset);
  	offset += (64 + key_t_value*8);
  	nettle_mpz_set_str_256_u(pubkey.g, (64 + key_t_value*8), key+offset);
  	offset += (64 + key_t_value*8);
  	nettle_mpz_set_str_256_u(pubkey.y, (64 + key_t_value*8), key+offset);
  
  	/* Digest content of "buf" and verify its DSA signature in "sigblock"*/
  	res = _digest_nettle(SHA1_DIGEST_SIZE, (unsigned char*)sldns_buffer_begin(buf),
  						(unsigned int)sldns_buffer_limit(buf), (unsigned char*)digest);
  	res &= dsa_sha1_verify_digest(&pubkey, digest, &signature);
  
  	/* Clear and return */
  	nettle_dsa_signature_clear(&signature);
  	nettle_dsa_public_key_clear(&pubkey);
  	if (!res)
  		return "DSA signature verification failed";
  	else
  		return NULL;
  }
  #endif /* USE_DSA */
  
  static char *
  _verify_nettle_rsa(sldns_buffer* buf, unsigned int digest_size, char* sigblock,
  	unsigned int sigblock_len, uint8_t* key, unsigned int keylen)
  {
  	uint16_t exp_len = 0;
  	size_t exp_offset = 0, mod_offset = 0;
  	struct rsa_public_key pubkey;
  	mpz_t signature;
  	int res = 0;
  
  	/* RSA pubkey parsing as per RFC 3110 sec. 2 */
  	if( keylen <= 1) {
  		return "null RSA key";
  	}
  	if (key[0] != 0) {
  		/* 1-byte length */
  		exp_len = key[0];
  		exp_offset = 1;
  	} else {
  		/* 1-byte NUL + 2-bytes exponent length */
  		if (keylen < 3) {
  			return "incorrect RSA key length";
  		}
  		exp_len = READ_UINT16(key+1);
  		if (exp_len == 0)
  			return "null RSA exponent length";
  		exp_offset = 3;
  	}
  	/* Check that we are not over-running input length */
  	if (keylen < exp_offset + exp_len + 1) {
  		return "RSA key content shorter than expected";
  	}
  	mod_offset = exp_offset + exp_len;
  	nettle_rsa_public_key_init(&pubkey);
  	pubkey.size = keylen - mod_offset;
  	nettle_mpz_set_str_256_u(pubkey.e, exp_len, &key[exp_offset]);
  	nettle_mpz_set_str_256_u(pubkey.n, pubkey.size, &key[mod_offset]);
  
  	/* Digest content of "buf" and verify its RSA signature in "sigblock"*/
  	nettle_mpz_init_set_str_256_u(signature, sigblock_len, (uint8_t*)sigblock);
  	switch (digest_size) {
  		case SHA1_DIGEST_SIZE:
  		{
  			uint8_t digest[SHA1_DIGEST_SIZE];
  			res = _digest_nettle(SHA1_DIGEST_SIZE, (unsigned char*)sldns_buffer_begin(buf),
  						(unsigned int)sldns_buffer_limit(buf), (unsigned char*)digest);
  			res &= rsa_sha1_verify_digest(&pubkey, digest, signature);
  			break;
  		}
  		case SHA256_DIGEST_SIZE:
  		{
  			uint8_t digest[SHA256_DIGEST_SIZE];
  			res = _digest_nettle(SHA256_DIGEST_SIZE, (unsigned char*)sldns_buffer_begin(buf),
  						(unsigned int)sldns_buffer_limit(buf), (unsigned char*)digest);
  			res &= rsa_sha256_verify_digest(&pubkey, digest, signature);
  			break;
  		}
  		case SHA512_DIGEST_SIZE:
  		{
  			uint8_t digest[SHA512_DIGEST_SIZE];
  			res = _digest_nettle(SHA512_DIGEST_SIZE, (unsigned char*)sldns_buffer_begin(buf),
  						(unsigned int)sldns_buffer_limit(buf), (unsigned char*)digest);
  			res &= rsa_sha512_verify_digest(&pubkey, digest, signature);
  			break;
  		}
  		default:
  			break;
  	}
  
  	/* Clear and return */
  	nettle_rsa_public_key_clear(&pubkey);
  	mpz_clear(signature);
  	if (!res) {
  		return "RSA signature verification failed";
  	} else {
  		return NULL;
  	}
  }
  
  #ifdef USE_ECDSA
  static char *
  _verify_nettle_ecdsa(sldns_buffer* buf, unsigned int digest_size, unsigned char* sigblock,
  	unsigned int sigblock_len, unsigned char* key, unsigned int keylen)
  {
  	int res = 0;
  	struct ecc_point pubkey;
  	struct dsa_signature signature;
  
  	/* Always matched strength, as per RFC 6605 sec. 1 */
  	if (sigblock_len != 2*digest_size || keylen != 2*digest_size) {
  		return "wrong ECDSA signature length";
  	}
  
  	/* Parse ECDSA signature as per RFC 6605 sec. 4 */
  	nettle_dsa_signature_init(&signature);
  	switch (digest_size) {
  		case SHA256_DIGEST_SIZE:
  		{
  			uint8_t digest[SHA256_DIGEST_SIZE];
  			mpz_t x, y;
  			nettle_ecc_point_init(&pubkey, &nettle_secp_256r1);
  			nettle_mpz_init_set_str_256_u(x, SHA256_DIGEST_SIZE, key);
  			nettle_mpz_init_set_str_256_u(y, SHA256_DIGEST_SIZE, key+SHA256_DIGEST_SIZE);
  			nettle_mpz_set_str_256_u(signature.r, SHA256_DIGEST_SIZE, sigblock);
  			nettle_mpz_set_str_256_u(signature.s, SHA256_DIGEST_SIZE, sigblock+SHA256_DIGEST_SIZE);
  			res = _digest_nettle(SHA256_DIGEST_SIZE, (unsigned char*)sldns_buffer_begin(buf),
  						(unsigned int)sldns_buffer_limit(buf), (unsigned char*)digest);
  			res &= nettle_ecc_point_set(&pubkey, x, y);
  			res &= nettle_ecdsa_verify (&pubkey, SHA256_DIGEST_SIZE, digest, &signature);
  			mpz_clear(x);
  			mpz_clear(y);
  			break;
  		}
  		case SHA384_DIGEST_SIZE:
  		{
  			uint8_t digest[SHA384_DIGEST_SIZE];
  			mpz_t x, y;
  			nettle_ecc_point_init(&pubkey, &nettle_secp_384r1);
  			nettle_mpz_init_set_str_256_u(x, SHA384_DIGEST_SIZE, key);
  			nettle_mpz_init_set_str_256_u(y, SHA384_DIGEST_SIZE, key+SHA384_DIGEST_SIZE);
  			nettle_mpz_set_str_256_u(signature.r, SHA384_DIGEST_SIZE, sigblock);
  			nettle_mpz_set_str_256_u(signature.s, SHA384_DIGEST_SIZE, sigblock+SHA384_DIGEST_SIZE);
  			res = _digest_nettle(SHA384_DIGEST_SIZE, (unsigned char*)sldns_buffer_begin(buf),
  						(unsigned int)sldns_buffer_limit(buf), (unsigned char*)digest);
  			res &= nettle_ecc_point_set(&pubkey, x, y);
  			res &= nettle_ecdsa_verify (&pubkey, SHA384_DIGEST_SIZE, digest, &signature);
  			mpz_clear(x);
  			mpz_clear(y);
  			nettle_ecc_point_clear(&pubkey);
  			break;
  		}
  		default:
  			return "unknown ECDSA algorithm";
  	}
  
  	/* Clear and return */
  	nettle_dsa_signature_clear(&signature);
  	if (!res)
  		return "ECDSA signature verification failed";
  	else
  		return NULL;
  }
  #endif
  
  #ifdef USE_ED25519
  static char *
  _verify_nettle_ed25519(sldns_buffer* buf, unsigned char* sigblock,
  	unsigned int sigblock_len, unsigned char* key, unsigned int keylen)
  {
  	int res = 0;
  
  	if(sigblock_len != ED25519_SIGNATURE_SIZE) {
  		return "wrong ED25519 signature length";
  	}
  	if(keylen != ED25519_KEY_SIZE) {
  		return "wrong ED25519 key length";
  	}
  
  	res = ed25519_sha512_verify((uint8_t*)key, sldns_buffer_limit(buf),
  		sldns_buffer_begin(buf), (uint8_t*)sigblock);
  
  	if (!res)
  		return "ED25519 signature verification failed";
  	else
  		return NULL;
  }
  #endif
  
  /**
   * Check a canonical sig+rrset and signature against a dnskey
   * @param buf: buffer with data to verify, the first rrsig part and the
   *	canonicalized rrset.
   * @param algo: DNSKEY algorithm.
   * @param sigblock: signature rdata field from RRSIG
   * @param sigblock_len: length of sigblock data.
   * @param key: public key data from DNSKEY RR.
   * @param keylen: length of keydata.
   * @param reason: bogus reason in more detail.
   * @return secure if verification succeeded, bogus on crypto failure,
   *	unchecked on format errors and alloc failures.
   */
  enum sec_status
  verify_canonrrset(sldns_buffer* buf, int algo, unsigned char* sigblock,
  	unsigned int sigblock_len, unsigned char* key, unsigned int keylen,
  	char** reason)
  {
  	unsigned int digest_size = 0;
  
  	if (sigblock_len == 0 || keylen == 0) {
  		*reason = "null signature";
  		return sec_status_bogus;
  	}
  
  	switch(algo) {
  #if defined(USE_DSA) && defined(USE_SHA1)
  	case LDNS_DSA:
  	case LDNS_DSA_NSEC3:
  		*reason = _verify_nettle_dsa(buf, sigblock, sigblock_len, key, keylen);
  		if (*reason != NULL)
  			return sec_status_bogus;
  		else
  			return sec_status_secure;
  #endif /* USE_DSA */
  
  #ifdef USE_SHA1
  	case LDNS_RSASHA1:
  	case LDNS_RSASHA1_NSEC3:
  		digest_size = (digest_size ? digest_size : SHA1_DIGEST_SIZE);
  #endif
  		/* double fallthrough annotation to please gcc parser */
  		/* fallthrough */
  #ifdef USE_SHA2
  		/* fallthrough */
  	case LDNS_RSASHA256:
  		digest_size = (digest_size ? digest_size : SHA256_DIGEST_SIZE);
  		/* fallthrough */
  	case LDNS_RSASHA512:
  		digest_size = (digest_size ? digest_size : SHA512_DIGEST_SIZE);
  
  #endif
  		*reason = _verify_nettle_rsa(buf, digest_size, (char*)sigblock,
  						sigblock_len, key, keylen);
  		if (*reason != NULL)
  			return sec_status_bogus;
  		else
  			return sec_status_secure;
  
  #ifdef USE_ECDSA
  	case LDNS_ECDSAP256SHA256:
  		digest_size = (digest_size ? digest_size : SHA256_DIGEST_SIZE);
  		/* fallthrough */
  	case LDNS_ECDSAP384SHA384:
  		digest_size = (digest_size ? digest_size : SHA384_DIGEST_SIZE);
  		*reason = _verify_nettle_ecdsa(buf, digest_size, sigblock,
  						sigblock_len, key, keylen);
  		if (*reason != NULL)
  			return sec_status_bogus;
  		else
  			return sec_status_secure;
  #endif
  #ifdef USE_ED25519
  	case LDNS_ED25519:
  		*reason = _verify_nettle_ed25519(buf, sigblock, sigblock_len,
  			key, keylen);
  		if (*reason != NULL)
  			return sec_status_bogus;
  		else
  			return sec_status_secure;
  #endif
  	case LDNS_RSAMD5:
  	case LDNS_ECC_GOST:
  	default:
  		*reason = "unable to verify signature, unknown algorithm";
  		return sec_status_bogus;
  	}
  }
  
  #endif /* HAVE_SSL or HAVE_NSS or HAVE_NETTLE */
  