yuzu-emu/mbedtls
1
0
Fork 0
mirror of https://github.com/yuzu-emu/mbedtls.git synced 2024-11-22 23:45:49 +01:00
Code Issues Packages Projects Releases Wiki Activity

Remove function pointers from curve structure

Browse Source 
They're not needed in practice, and removing them decreases the code size
slightly and provides less opportunities for an attacker.
This commit is contained in:
Manuel Pégourié-Gonnard 2019-11-21 09:18:29 +01:00
parent e714332563
commit 1c6f7eae2d
3 changed files with 10 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
include/tinycrypt/ecc.h
View File

@ -131,10 +131,6 @@ struct uECC_Curve_t {
uECC_word_t n[NUM_ECC_WORDS];
uECC_word_t G[NUM_ECC_WORDS * 2];
uECC_word_t b[NUM_ECC_WORDS];
void (*double_jacobian)(uECC_word_t * X1, uECC_word_t * Y1, uECC_word_t * Z1,
uECC_Curve curve);
void (*x_side)(uECC_word_t *result, const uECC_word_t *x, uECC_Curve curve);
void (*mmod_fast)(uECC_word_t *result, uECC_word_t *product);
};
/*
@ -147,15 +143,6 @@ struct uECC_Curve_t {
void double_jacobian_default(uECC_word_t * X1, uECC_word_t * Y1,
uECC_word_t * Z1, uECC_Curve curve);
/*
* @brief Computes x^3 + ax + b. result must not overlap x.
* @param result OUT -- x^3 + ax + b
* @param x IN -- value of x
* @param curve IN -- elliptic curve
*/
void x_side_default(uECC_word_t *result, const uECC_word_t *x,
uECC_Curve curve);
/*
* @brief Computes result = product % curve_p
* from http://www.nsa.gov/ia/_files/nist-routines.pdf
@ -201,9 +188,6 @@ static const struct uECC_Curve_t curve_secp256r1 = {
BYTES_TO_WORDS_8(BC, 86, 98, 76, 55, BD, EB, B3),
BYTES_TO_WORDS_8(E7, 93, 3A, AA, D8, 35, C6, 5A)
},
&double_jacobian_default,
&x_side_default,
&vli_mmod_fast_secp256r1
};
uECC_Curve uECC_secp256r1(void);

12
tinycrypt/ecc.c
View File

@ -622,7 +622,13 @@ void double_jacobian_default(uECC_word_t * X1, uECC_word_t * Y1,
uECC_vli_set(Y1, t4);
}
void x_side_default(uECC_word_t *result,
/*
* @brief Computes x^3 + ax + b. result must not overlap x.
* @param result OUT -- x^3 + ax + b
* @param x IN -- value of x
* @param curve IN -- elliptic curve
*/
static void x_side_default(uECC_word_t *result,
const uECC_word_t *x,
uECC_Curve curve)
{
@ -775,7 +781,7 @@ static void XYcZ_initial_double(uECC_word_t * X1, uECC_word_t * Y1,
uECC_vli_set(Y2, Y1);
apply_z(X1, Y1, z);
curve->double_jacobian(X1, Y1, z, curve);
double_jacobian_default(X1, Y1, z, curve);
apply_z(X2, Y2, z);
}
@ -1050,7 +1056,7 @@ int uECC_valid_point(const uECC_word_t *point, uECC_Curve curve)
}
uECC_vli_modMult_fast(tmp1, point + num_words, point + num_words);
curve->x_side(tmp2, point, curve); /* tmp2 = x^3 + ax + b */
x_side_default(tmp2, point, curve); /* tmp2 = x^3 + ax + b */
/* Make sure that y^2 == x^3 + ax + b */
if (uECC_vli_equal(tmp1, tmp2) != 0)

2
tinycrypt/ecc_dsa.c
View File

@ -280,7 +280,7 @@ int uECC_verify(const uint8_t *public_key, const uint8_t *message_hash,
for (i = num_bits - 2; i >= 0; --i) {
uECC_word_t index;
curve->double_jacobian(rx, ry, z, curve);
double_jacobian_default(rx, ry, z, curve);
index = (!!uECC_vli_testBit(u1, i)) | ((!!uECC_vli_testBit(u2, i)) << 1);
point = points[index];