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Hardcode numwords in semi-internal vli_numBits()

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Manuel Pégourié-Gonnard 2019-11-04 12:56:59 +01:00
parent 94e48498ef
commit 2bf5a129cf
3 changed files with 10 additions and 13 deletions
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3
include/tinycrypt/ecc.h
View file

@ -476,8 +476,7 @@ void uECC_vli_modAdd(uECC_word_t *result, const uECC_word_t *left,
* @param max_words IN -- number of words
* @return number of bits in given vli
*/
bitcount_t uECC_vli_numBits(const uECC_word_t *vli,
const wordcount_t max_words);
bitcount_t uECC_vli_numBits(const uECC_word_t *vli);
/*
* @brief Erases (set to 0) vli

14
tinycrypt/ecc.c
View file

@ -121,27 +121,25 @@ uECC_word_t uECC_vli_testBit(const uECC_word_t *vli, bitcount_t bit)
}
/* Counts the number of words in vli. */
static wordcount_t vli_numDigits(const uECC_word_t *vli,
const wordcount_t max_words)
static wordcount_t vli_numDigits(const uECC_word_t *vli)
{
wordcount_t i;
/* Search from the end until we find a non-zero digit. We do it in reverse
* because we expect that most digits will be nonzero. */
for (i = max_words - 1; i >= 0 && vli[i] == 0; --i) {
for (i = NUM_ECC_WORDS - 1; i >= 0 && vli[i] == 0; --i) {
}
return (i + 1);
}
bitcount_t uECC_vli_numBits(const uECC_word_t *vli,
const wordcount_t max_words)
bitcount_t uECC_vli_numBits(const uECC_word_t *vli)
{
uECC_word_t i;
uECC_word_t digit;
wordcount_t num_digits = vli_numDigits(vli, max_words);
wordcount_t num_digits = vli_numDigits(vli);
if (num_digits == 0) {
return 0;
}
@ -461,7 +459,7 @@ void uECC_vli_mmod(uECC_word_t *result, uECC_word_t *product,
/* Shift mod so its highest set bit is at the maximum position. */
bitcount_t shift = (num_words * 2 * uECC_WORD_BITS) -
uECC_vli_numBits(mod, num_words);
uECC_vli_numBits(mod);
wordcount_t word_shift = shift / uECC_WORD_BITS;
wordcount_t bit_shift = shift % uECC_WORD_BITS;
uECC_word_t carry = 0;
@ -1029,7 +1027,7 @@ int uECC_generate_random_int(uECC_word_t *random, const uECC_word_t *top,
{
uECC_word_t mask = (uECC_word_t)-1;
uECC_word_t tries;
bitcount_t num_bits = uECC_vli_numBits(top, num_words);
bitcount_t num_bits = uECC_vli_numBits(top);
if (!g_rng_function) {
return 0;

6
tinycrypt/ecc_dsa.c
View file

@ -159,7 +159,7 @@ int uECC_sign_with_k(const uint8_t *private_key, const uint8_t *message_hash,
bits2int(tmp, message_hash, hash_size, curve);
uECC_vli_modAdd(s, tmp, s, curve->n, num_n_words); /* s = e + r*d */
uECC_vli_modMult(s, s, k, curve->n, num_n_words); /* s = (e + r*d) / k */
if (uECC_vli_numBits(s, num_n_words) > (bitcount_t)curve->num_bytes * 8) {
if (uECC_vli_numBits(s) > (bitcount_t)curve->num_bytes * 8) {
return 0;
}
@ -264,8 +264,8 @@ int uECC_verify(const uint8_t *public_key, const uint8_t *message_hash,
points[1] = curve->G;
points[2] = _public;
points[3] = sum;
num_bits = smax(uECC_vli_numBits(u1, num_n_words),
uECC_vli_numBits(u2, num_n_words));
num_bits = smax(uECC_vli_numBits(u1),
uECC_vli_numBits(u2));
point = points[(!!uECC_vli_testBit(u1, num_bits - 1)) |
((!!uECC_vli_testBit(u2, num_bits - 1)) << 1)];