status-go/vendor/github.com/mutecomm/go-sqlcipher/v4/hmac_init.c

95 lines
2.3 KiB
C

/* LibTomCrypt, modular cryptographic library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */
#include "tomcrypt_private.h"
/**
@file hmac_init.c
HMAC support, initialize state, Tom St Denis/Dobes Vandermeer
*/
#ifdef LTC_HMAC
#define LTC_HMAC_BLOCKSIZE hash_descriptor[hash].blocksize
/**
Initialize an HMAC context.
@param hmac The HMAC state
@param hash The index of the hash you want to use
@param key The secret key
@param keylen The length of the secret key (octets)
@return CRYPT_OK if successful
*/
int hmac_init(hmac_state *hmac, int hash, const unsigned char *key, unsigned long keylen)
{
unsigned char *buf;
unsigned long hashsize;
unsigned long i, z;
int err;
LTC_ARGCHK(hmac != NULL);
LTC_ARGCHK(key != NULL);
/* valid hash? */
if ((err = hash_is_valid(hash)) != CRYPT_OK) {
return err;
}
hmac->hash = hash;
hashsize = hash_descriptor[hash].hashsize;
/* valid key length? */
if (keylen == 0) {
return CRYPT_INVALID_KEYSIZE;
}
/* allocate ram for buf */
buf = XMALLOC(LTC_HMAC_BLOCKSIZE);
if (buf == NULL) {
return CRYPT_MEM;
}
/* check hash block fits */
if (sizeof(hmac->key) < LTC_HMAC_BLOCKSIZE) {
err = CRYPT_BUFFER_OVERFLOW;
goto LBL_ERR;
}
/* (1) make sure we have a large enough key */
if(keylen > LTC_HMAC_BLOCKSIZE) {
z = LTC_HMAC_BLOCKSIZE;
if ((err = hash_memory(hash, key, keylen, hmac->key, &z)) != CRYPT_OK) {
goto LBL_ERR;
}
keylen = hashsize;
} else {
XMEMCPY(hmac->key, key, (size_t)keylen);
}
if(keylen < LTC_HMAC_BLOCKSIZE) {
zeromem((hmac->key) + keylen, (size_t)(LTC_HMAC_BLOCKSIZE - keylen));
}
/* Create the initialization vector for step (3) */
for(i=0; i < LTC_HMAC_BLOCKSIZE; i++) {
buf[i] = hmac->key[i] ^ 0x36;
}
/* Pre-pend that to the hash data */
if ((err = hash_descriptor[hash].init(&hmac->md)) != CRYPT_OK) {
goto LBL_ERR;
}
if ((err = hash_descriptor[hash].process(&hmac->md, buf, LTC_HMAC_BLOCKSIZE)) != CRYPT_OK) {
goto LBL_ERR;
}
LBL_ERR:
#ifdef LTC_CLEAN_STACK
zeromem(buf, LTC_HMAC_BLOCKSIZE);
#endif
XFREE(buf);
return err;
}
#endif