66 lines
2.0 KiB
C
66 lines
2.0 KiB
C
/* LibTomCrypt, modular cryptographic library -- Tom St Denis */
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/* SPDX-License-Identifier: Unlicense */
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#include "tomcrypt_private.h"
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#if defined(LTC_MECC) && defined(LTC_SSH)
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/**
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@file ecc_verify_hash.c
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ECC Crypto, Tom St Denis
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*/
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/**
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Verify an ECC signature (RFC5656 / SSH format)
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@param sig The signature to verify
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@param siglen The length of the signature (octets)
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@param hash The hash (message digest) that was signed
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@param hashlen The length of the hash (octets)
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@param stat [out] Result of signature, 1==valid, 0==invalid
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@param key The corresponding public ECC key
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@return CRYPT_OK if successful (even if the signature is not valid)
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*/
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int ecc_verify_hash_rfc5656(const unsigned char *sig, unsigned long siglen,
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const unsigned char *hash, unsigned long hashlen,
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int *stat, const ecc_key *key)
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{
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void *r, *s;
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int err;
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char name[64], name2[64];
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unsigned long namelen = sizeof(name);
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unsigned long name2len = sizeof(name2);
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unsigned long slen = siglen;
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LTC_ARGCHK(sig != NULL);
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LTC_ARGCHK(key != NULL);
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if ((err = ltc_mp_init_multi(&r, &s, LTC_NULL)) != CRYPT_OK) return err;
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/* Decode as SSH data sequence, per RFC4251 */
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if ((err = ssh_decode_sequence_multi(sig, &slen,
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LTC_SSHDATA_STRING, name, &namelen,
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LTC_SSHDATA_MPINT, r,
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LTC_SSHDATA_MPINT, s,
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LTC_SSHDATA_EOL, LTC_NULL)) != CRYPT_OK) goto error;
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if (slen != siglen) {
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err = CRYPT_INVALID_PACKET;
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goto error;
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}
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/* Check curve matches identifier string */
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if ((err = ecc_ssh_ecdsa_encode_name(name2, &name2len, key)) != CRYPT_OK) goto error;
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if (XSTRCMP(name,name2) != 0) {
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err = CRYPT_INVALID_ARG;
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goto error;
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}
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err = ecc_verify_hash_internal(r, s, hash, hashlen, stat, key);
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error:
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ltc_mp_deinit_multi(r, s, LTC_NULL);
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return err;
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}
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#endif
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