int
rsa_vrfy_msg(struct rsa_public_key *pub,mpz_t sign,const uint8_t *msg,const size_t len)
{
uint8_t digest[SHA1_DIGEST_SIZE];
struct sha1_ctx sha1ctx;
bzero(&sha1ctx,sizeof(struct sha1_ctx));
bzero(&digest[0],SHA1_DIGEST_SIZE);
sha1_init(&sha1ctx);
sha1_update(&sha1ctx,len,msg);
sha1_digest(&sha1ctx,SHA1_DIGEST_SIZE,digest);
//if (!rsa_sha1_verify(pub, &sha1ctx, sign)) {
if (!rsa_sha1_verify_digest(pub, &digest[0], sign)) {
return SIGN_INVALID;
}
return SIGN_VALID;
}
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;
}
}
