yuzu/mbedtls
1
0
Fork 0
mirror of https://github.com/yuzu-emu/mbedtls.git synced 2025-02-02 11:21:08 +00:00
Code Issues Packages Projects Releases Wiki Activity

Hardcode numwords in semi-internal vli_numBits()

Browse source
This commit is contained in:
Manuel Pégourié-Gonnard 2019-11-04 12:56:59 +01:00
parent 94e48498ef
commit 2bf5a129cf
3 changed files with 10 additions and 13 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

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 * @param max_words IN -- number of words
* @return number of bits in given vli * @return number of bits in given vli
*/ */
bitcount_t uECC_vli_numBits(const uECC_word_t *vli, bitcount_t uECC_vli_numBits(const uECC_word_t *vli);
const wordcount_t max_words);
/* /*
* @brief Erases (set to 0) 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. */ /* Counts the number of words in vli. */
static wordcount_t vli_numDigits(const uECC_word_t *vli, static wordcount_t vli_numDigits(const uECC_word_t *vli)
const wordcount_t max_words)
{ {
wordcount_t i; wordcount_t i;
/* Search from the end until we find a non-zero digit. We do it in reverse /* 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. */ * 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); return (i + 1);
} }
bitcount_t uECC_vli_numBits(const uECC_word_t *vli, bitcount_t uECC_vli_numBits(const uECC_word_t *vli)
const wordcount_t max_words)
{ {
uECC_word_t i; uECC_word_t i;
uECC_word_t digit; uECC_word_t digit;
wordcount_t num_digits = vli_numDigits(vli, max_words); wordcount_t num_digits = vli_numDigits(vli);
if (num_digits == 0) { if (num_digits == 0) {
return 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. */ /* Shift mod so its highest set bit is at the maximum position. */
bitcount_t shift = (num_words * 2 * uECC_WORD_BITS) - 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 word_shift = shift / uECC_WORD_BITS;
wordcount_t bit_shift = shift % uECC_WORD_BITS; wordcount_t bit_shift = shift % uECC_WORD_BITS;
uECC_word_t carry = 0; 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 mask = (uECC_word_t)-1;
uECC_word_t tries; 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) { if (!g_rng_function) {
return 0; 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); bits2int(tmp, message_hash, hash_size, curve);
uECC_vli_modAdd(s, tmp, s, curve->n, num_n_words); /* s = e + r*d */ 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 */ 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; return 0;
} }
@ -264,8 +264,8 @@ int uECC_verify(const uint8_t *public_key, const uint8_t *message_hash,
points[1] = curve->G; points[1] = curve->G;
points[2] = _public; points[2] = _public;
points[3] = sum; points[3] = sum;
num_bits = smax(uECC_vli_numBits(u1, num_n_words), num_bits = smax(uECC_vli_numBits(u1),
uECC_vli_numBits(u2, num_n_words)); uECC_vli_numBits(u2));
point = points[(!!uECC_vli_testBit(u1, num_bits - 1)) | point = points[(!!uECC_vli_testBit(u1, num_bits - 1)) |
((!!uECC_vli_testBit(u2, num_bits - 1)) << 1)]; ((!!uECC_vli_testBit(u2, num_bits - 1)) << 1)];