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unbound/validator/val_secalgo.c
wouter eb3fb269b0 - ED448 support. 
git-svn-id: https://unbound.nlnetlabs.nl/svn/trunk@4607 be551aaa-1e26-0410-a405-d3ace91eadb9
2018-04-05 14:44:17 +00:00

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/*
* 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;
/* 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:
(void)SHA1(buf, len, res);
return 1;
default:
return 0;
}
}
void
secalgo_hash_sha256(unsigned char* buf, size_t len, unsigned char* res)
{
(void)SHA256(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:
#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:
(void)SHA1(buf, len, res);
return 1;
#endif
#ifdef HAVE_EVP_SHA256
case LDNS_SHA256:
(void)SHA256(buf, len, res);
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:
(void)SHA384(buf, len, res);
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;
}
}
/**
* 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);
}
#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 */
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