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/* See LICENSE file for copyright and license details. */
#include "common.h"
/**
* Absorb the last part of the message and fetch the hash
* without wiping sensitive data when possible
*
* You may use `&state->sponge` for continued squeezing
*
* @param state The hashing state
* @param msg The rest of the message, may be `NULL`, may be modified
* @param msglen The length of the partial message
* @param bits The number of bits at the end of the message not covered by `msglen`
* @param suffix The suffix concatenate to the message, only '1':s and '0':s, and NUL-termination
* @param hashsum Output parameter for the hashsum, may be `NULL`
* @return Zero on success, -1 on error
*/
int
libkeccak_hmac_fast_digest(libkeccak_hmac_state_t *restrict state, const void *restrict msg_, size_t msglen,
size_t bits, const char *restrict suffix, void *restrict hashsum)
{
const char *restrict msg = msg_;
size_t hashsize = (size_t)state->sponge.n >> 3;
char *tmp = malloc((size_t)((state->sponge.n + 7) >> 3) * sizeof(char));
char leftover[2];
size_t newlen;
if (!tmp)
return -1;
if (!(state->key_length & 7)) {
if (libkeccak_fast_digest(&state->sponge, msg, msglen, bits, suffix, tmp) < 0)
goto fail;
goto stage_2;
}
if (libkeccak_hmac_fast_update(state, msg, msglen) < 0)
goto fail;
leftover[0] = state->leftover;
if (bits) {
leftover[0] |= (char)(msg[msglen] >> (state->key_length & 7));
leftover[1] = (char)((unsigned char)msg[msglen] << (8 - (state->key_length & 7)));
}
newlen = (state->key_length & 7) + bits;
if (libkeccak_fast_digest(&state->sponge, leftover, newlen >> 3, newlen & 7, suffix, tmp) < 0)
goto fail;
stage_2:
bits = state->sponge.n & 7;
state->key_ipad = state->key_opad;
if (libkeccak_hmac_fast_update(state, NULL, 0) < 0)
goto fail;
if (!(state->key_length & 7)) {
if (libkeccak_fast_digest(&state->sponge, tmp, hashsize, bits, suffix, hashsum) < 0)
goto fail;
goto stage_3;
}
if (libkeccak_hmac_fast_update(state, tmp, hashsize) < 0)
goto fail;
leftover[0] = state->leftover;
if (bits) {
leftover[0] |= (char)(tmp[hashsize] >> (state->key_length & 7));
leftover[1] = (char)((unsigned char)tmp[hashsize] << (8 - (state->key_length & 7)));
}
newlen = (state->key_length & 7) + bits;
if (libkeccak_fast_digest(&state->sponge, leftover, newlen >> 3, newlen & 7, suffix, tmp) < 0)
goto fail;
stage_3:
free(tmp);
return 0;
fail:
free(tmp);
return -1;
}
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