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68 lines
2.4 KiB
C
68 lines
2.4 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 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->sas_valid){
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keyring_send_sas_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->sas_public))
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return WHY("Signature verification failed");
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return 0;
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}
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// sign the hash of a message, adding the signature to the end of the message buffer.
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int crypto_sign_message(struct keyring_identity *identity, unsigned char *content, size_t buffer_len, size_t *content_len)
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{
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if (*content_len + SIGNATURE_BYTES > buffer_len)
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return WHYF("Insufficient space in message buffer to add signature. %zu, need %zu",buffer_len, *content_len + SIGNATURE_BYTES);
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struct keypair *key = keyring_find_sas_private(keyring, identity);
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if (!key)
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return WHY("Could not find signing key");
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unsigned char hash[crypto_hash_sha512_BYTES];
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crypto_hash_sha512(hash, content, *content_len);
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if (crypto_sign_detached(&content[*content_len], NULL, hash, crypto_hash_sha512_BYTES, key->private_key))
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return WHY("Signing failed");
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*content_len += SIGNATURE_BYTES;
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return 0;
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}
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