mirror of
https://github.com/servalproject/serval-dna.git
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97 lines
3.1 KiB
C
97 lines
3.1 KiB
C
/*
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Serval DNA internal cryptographic operations
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Copyright 2013 Serval Project Inc.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#include "serval.h"
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#include "overlay_address.h"
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#include "crypto.h"
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#include "keyring.h"
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// verify that the supplied keypair is valid (by rebuilding it)
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int crypto_isvalid_keypair(const sign_private_t *private_key, const sign_public_t *public_key)
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{
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sign_keypair_t test_key;
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crypto_sign_seed_keypair(test_key.public_key.binary, test_key.binary, private_key->binary);
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return memcmp(test_key.public_key.binary, public_key->binary, sizeof (sign_public_t)) == 0 ? 1 : 0;
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}
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int crypto_sign_to_sid(const sign_public_t *public_key, sid_t *sid)
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{
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if (crypto_sign_ed25519_pk_to_curve25519(sid->binary, public_key->binary))
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return WHY("Failed to convert sign key to sid");
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return 0;
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}
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int crypto_ismatching_sign_sid(const sign_public_t *public_key, const sid_t *sid)
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{
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sid_t test_sid;
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if (crypto_sign_to_sid(public_key, &test_sid)==0
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&& cmp_sid_t(&test_sid, sid)==0)
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return 1;
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return 0;
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}
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// verify the signature at the end of a message, on return message_len will be reduced by the length of the signature.
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int crypto_verify_message(struct subscriber *subscriber, unsigned char *message, size_t *message_len)
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{
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if (!subscriber->id_valid){
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keyring_send_identity_request(subscriber);
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return WHY("SAS key not currently on record, cannot verify");
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}
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if (*message_len < SIGNATURE_BYTES)
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return WHY("Message is too short to include a signature");
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*message_len -= SIGNATURE_BYTES;
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unsigned char hash[crypto_hash_sha512_BYTES];
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crypto_hash_sha512(hash,message,*message_len);
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if (crypto_sign_verify_detached(&message[*message_len], hash, crypto_hash_sha512_BYTES, subscriber->id_public.binary))
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return WHY("Signature verification failed");
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return 0;
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}
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int crypto_seed_keypair(sign_keypair_t *keypair, const char *fmt, ...)
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{
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va_list ap;
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va_start(ap, fmt);
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int n = vsnprintf(NULL, 0, fmt, ap);
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if (n<0)
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return WHYF_perror("vsnprintf(%s, ...)", fmt);
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va_end(ap);
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char str_seed[n+1];
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va_start(ap, fmt);
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if (vsnprintf(str_seed, sizeof str_seed, fmt, ap)<0)
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return WHYF_perror("vsnprintf(%s, ...)", fmt);
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va_end(ap);
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union {
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unsigned char hash[crypto_hash_sha512_BYTES];
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sign_private_t seed;
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} u;
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// The first 256 bits (32 bytes) of the hash will be used as the seed bytes
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crypto_hash_sha512(u.hash, (uint8_t *)str_seed, n);
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crypto_sign_seed_keypair(keypair->public_key.binary, keypair->binary, u.seed.binary);
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return 0;
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}
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