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SP int neg: fix handling of negative zero and mp_cond_copy

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mp_cond_copy: copy sign when available.
Check for zero and ensure sign is MP_ZPOS.
This commit is contained in:
Sean Parkinson
2021-02-08 14:19:25 +10:00
parent 2933db8915
commit 539ef512fc
3 changed files with 151 additions and 76 deletions
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188
wolfcrypt/src/sp_int.c
View File

@ -1991,6 +1991,20 @@ WOLFSSL_LOCAL int sp_ModExp_4096(sp_int* base, sp_int* exp, sp_int* mod,
static int _sp_mont_red(sp_int* a, sp_int* m, sp_int_digit mp);
#endif
/* Set the multi-precision number to zero.
*
* Assumes a is not NULL.
*
* @param [out] a SP integer to set to zero.
*/
static void _sp_zero(sp_int* a)
{
a->used = 0;
#ifdef WOLFSSL_SP_INT_NEGATIVE
a->sign = MP_ZPOS;
#endif
}
/* Initialize the multi-precision number to be zero.
*
* @param [out] a SP integer.
@ -2006,11 +2020,8 @@ int sp_init(sp_int* a)
err = MP_VAL;
}
if (err == MP_OKAY) {
a->used = 0;
_sp_zero(a);
a->size = SP_INT_DIGITS;
#ifdef WOLFSSL_SP_INT_NEGATIVE
a->sign = MP_ZPOS;
#endif
#ifdef HAVE_WOLF_BIGINT
wc_bigint_init(&a->raw);
#endif
@ -2046,46 +2057,34 @@ int sp_init_multi(sp_int* n1, sp_int* n2, sp_int* n3, sp_int* n4, sp_int* n5,
sp_int* n6)
{
if (n1 != NULL) {
n1->used = 0;
_sp_zero(n1);
n1->dp[0] = 0;
n1->size = SP_INT_DIGITS;
#ifdef WOLFSSL_SP_INT_NEGATIVE
n1->sign = MP_ZPOS;
#endif
}
if (n2 != NULL) {
n2->used = 0;
_sp_zero(n2);
n2->dp[0] = 0;
n2->size = SP_INT_DIGITS;
#ifdef WOLFSSL_SP_INT_NEGATIVE
n2->sign = MP_ZPOS;
#endif
}
if (n3 != NULL) {
n3->used = 0;
_sp_zero(n3);
n3->dp[0] = 0;
n3->size = SP_INT_DIGITS;
#ifdef WOLFSSL_SP_INT_NEGATIVE
n3->sign = MP_ZPOS;
#endif
}
if (n4 != NULL) {
n4->used = 0;
_sp_zero(n4);
n4->dp[0] = 0;
n4->size = SP_INT_DIGITS;
#ifdef WOLFSSL_SP_INT_NEGATIVE
n4->sign = MP_ZPOS;
#endif
}
if (n5 != NULL) {
n5->used = 0;
_sp_zero(n5);
n5->dp[0] = 0;
n5->size = SP_INT_DIGITS;
#ifdef WOLFSSL_SP_INT_NEGATIVE
n5->sign = MP_ZPOS;
#endif
}
if (n6 != NULL) {
n6->used = 0;
_sp_zero(n6);
n6->dp[0] = 0;
n6->size = SP_INT_DIGITS;
#ifdef WOLFSSL_SP_INT_NEGATIVE
n6->sign = MP_ZPOS;
#endif
}
return MP_OKAY;
@ -2137,21 +2136,6 @@ int sp_grow(sp_int* a, int l)
}
#endif /* !WOLFSSL_RSA_VERIFY_ONLY || !NO_DH || HAVE_ECC */
/* Set the multi-precision number to zero.
*
* Assumes a is not NULL.
*
* @param [out] a SP integer to set to zero.
*/
static void _sp_zero(sp_int* a)
{
a->dp[0] = 0;
a->used = 0;
#ifdef WOLFSSL_SP_INT_NEGATIVE
a->sign = MP_ZPOS;
#endif
}
#if !defined(WOLFSSL_RSA_VERIFY_ONLY)
/* Set the multi-precision number to zero.
*
@ -2177,10 +2161,7 @@ void sp_clear(sp_int* a)
for (i = 0; i < a->used; i++) {
a->dp[i] = 0;
}
a->used = 0;
#ifdef WOLFSSL_SP_INT_NEGATIVE
a->sign = MP_ZPOS;
#endif
_sp_zero(a);
}
}
@ -2194,10 +2175,7 @@ void sp_clear(sp_int* a)
void sp_forcezero(sp_int* a)
{
ForceZero(a->dp, a->used * sizeof(sp_int_digit));
a->used = 0;
#ifdef WOLFSSL_SP_INT_NEGATIVE
a->sign = MP_ZPOS;
#endif
_sp_zero(a);
#ifdef HAVE_WOLF_BIGINT
wc_bigint_zero(&a->raw);
#endif
@ -2321,14 +2299,23 @@ int sp_cond_swap_ct(sp_int * a, sp_int * b, int c, int m)
#endif
t->used = (int)((a->used ^ b->used) & mask);
#ifdef WOLFSSL_SP_INT_NEGATIVE
t->sign = (int)((a->sign ^ b->sign) & mask);
#endif
for (i = 0; i < c; i++) {
t->dp[i] = (a->dp[i] ^ b->dp[i]) & mask;
}
a->used ^= t->used;
#ifdef WOLFSSL_SP_INT_NEGATIVE
a->sign ^= t->sign;
#endif
for (i = 0; i < c; i++) {
a->dp[i] ^= t->dp[i];
}
b->used ^= t->used;
#ifdef WOLFSSL_SP_INT_NEGATIVE
b->sign ^= b->sign;
#endif
for (i = 0; i < c; i++) {
b->dp[i] ^= t->dp[i];
}
@ -2697,12 +2684,12 @@ int sp_set_bit(sp_int* a, int i)
*/
int sp_2expt(sp_int* a, int e)
{
int err = 0;
int err = MP_OKAY;
if (a == NULL) {
err = MP_VAL;
}
else {
if (err == MP_OKAY) {
_sp_zero(a);
err = sp_set_bit(a, e);
}
@ -2959,7 +2946,7 @@ int sp_add_d(sp_int* a, sp_int_digit d, sp_int* r)
r->sign = MP_ZPOS;
err = _sp_add_d(a, d, r);
}
else if ((a->used > 1) || (a->dp[0] >= d)) {
else if ((a->used > 1) || (a->dp[0] > d)) {
r->sign = MP_NEG;
_sp_sub_d(a, d, r);
}
@ -3080,7 +3067,12 @@ int sp_mul_d(sp_int* a, sp_int_digit d, sp_int* r)
if (err == MP_OKAY) {
_sp_mul_d(a, d, r, 0);
#ifdef WOLFSSL_SP_INT_NEGATIVE
r->sign = a->sign;
if (d == 0) {
r->sign = MP_ZPOS;
}
else {
r->sign = a->sign;
}
#endif
}
@ -3701,12 +3693,22 @@ int sp_add(sp_int* a, sp_int* b, sp_int* r)
err = _sp_add_off(a, b, r, 0);
}
else if (_sp_cmp_abs(a, b) != MP_LT) {
r->sign = a->sign;
err = _sp_sub_off(a, b, r, 0);
if (sp_iszero(r)) {
r->sign = MP_ZPOS;
}
else {
r->sign = a->sign;
}
}
else {
r->sign = b->sign;
err = _sp_sub_off(b, a, r, 0);
if (sp_iszero(r)) {
r->sign = MP_ZPOS;
}
else {
r->sign = b->sign;
}
}
#endif
}
@ -3744,12 +3746,22 @@ int sp_sub(sp_int* a, sp_int* b, sp_int* r)
err = _sp_add_off(a, b, r, 0);
}
else if (_sp_cmp_abs(a, b) != MP_LT) {
r->sign = a->sign;
err = _sp_sub_off(a, b, r, 0);
if (sp_iszero(r)) {
r->sign = MP_ZPOS;
}
else {
r->sign = a->sign;
}
}
else {
r->sign = 1 - a->sign;
err = _sp_sub_off(b, a, r, 0);
if (sp_iszero(r)) {
r->sign = MP_ZPOS;
}
else {
r->sign = 1 - a->sign;
}
}
#endif
}
@ -4180,8 +4192,7 @@ void sp_rshd(sp_int* a, int c)
int j;
if (c >= a->used) {
a->dp[0] = 0;
a->used = 0;
_sp_zero(a);
}
else {
for (i = c, j = 0; i < a->used; i++, j++) {
@ -4208,11 +4219,7 @@ void sp_rshb(sp_int* a, int n, sp_int* r)
int i = n >> SP_WORD_SHIFT;
if (i >= a->used) {
r->dp[0] = 0;
r->used = 0;
#ifdef WOLFSSL_SP_INT_NEGATIVE
r->sign = MP_ZPOS;
#endif
_sp_zero(r);
}
else {
int j;
@ -4231,7 +4238,12 @@ void sp_rshb(sp_int* a, int n, sp_int* r)
sp_clamp(r);
}
#ifdef WOLFSSL_SP_INT_NEGATIVE
r->sign = a->sign;
if (sp_iszero(r)) {
r->sign = MP_ZPOS;
}
else {
r->sign = a->sign;
}
#endif
}
}
@ -4465,12 +4477,22 @@ int sp_div(sp_int* a, sp_int* d, sp_int* r, sp_int* rem)
}
sp_copy(sa, rem);
sp_clamp(rem);
#ifdef WOLFSSL_SP_INT_NEGATIVE
if (sp_iszero(rem)) {
rem->sign = MP_ZPOS;
}
#endif
}
if (r != NULL) {
sp_copy(tr, r);
sp_clamp(r);
#ifdef WOLFSSL_SP_INT_NEGATIVE
r->sign = (aSign == dSign) ? MP_ZPOS : MP_NEG;
if (sp_iszero(r)) {
r->sign = MP_ZPOS;
}
else {
r->sign = (aSign == dSign) ? MP_ZPOS : MP_NEG;
}
#endif /* WOLFSSL_SP_INT_NEGATIVE */
}
}
@ -9248,7 +9270,7 @@ int sp_div_2d(sp_int* a, int e, sp_int* r, sp_int* rem)
if (remBits <= 0) {
/* Shifting down by more bits than in number. */
sp_set(r, 0);
_sp_zero(r);
sp_copy(a, rem);
}
else {
@ -9266,6 +9288,9 @@ int sp_div_2d(sp_int* a, int e, sp_int* r, sp_int* rem)
rem->dp[rem->used - 1] &= ((sp_int_digit)1 << e) - 1;
}
sp_clamp(rem);
#ifdef WOLFSSL_SP_INT_NEGATIVE
rem->sign = MP_ZPOS;
#endif
}
}
}
@ -9296,9 +9321,6 @@ int sp_mod_2d(sp_int* a, int e, sp_int* r)
int digits = (e + SP_WORD_SIZE - 1) >> SP_WORD_SHIFT;
if (a != r) {
XMEMCPY(r->dp, a->dp, digits * sizeof(sp_int_digit));
#ifdef WOLFSSL_SP_INT_NEGATIVE
r->sign = a->sign;
#endif /* WOLFSSL_SP_INT_NEGATIVE */
}
/* Set used and mask off top digit of result. */
r->used = digits;
@ -9307,6 +9329,14 @@ int sp_mod_2d(sp_int* a, int e, sp_int* r)
r->dp[r->used - 1] &= ((sp_int_digit)1 << e) - 1;
}
sp_clamp(r);
#ifdef WOLFSSL_SP_INT_NEGATIVE
if (sp_iszero(r)) {
r->sign = MP_ZPOS;
}
else if (a != r) {
r->sign = a->sign;
}
#endif
}
return err;
@ -12611,8 +12641,12 @@ static int _sp_read_radix_16(sp_int* a, const char* in)
if (err == MP_OKAY) {
a->used = j + 1;
sp_clamp(a);
#ifdef WOLFSSL_SP_INT_NEGATIVE
if (sp_iszero(a)) {
a->sign = MP_ZPOS;
}
#endif
}
return err;
}
#endif /* WOLFSSL_SP_MATH_ALL || HAVE_ECC */
@ -12637,6 +12671,7 @@ static int _sp_read_radix_10(sp_int* a, const char* in)
int len;
char ch;
_sp_zero(a);
#ifdef WOLFSSL_SP_INT_NEGATIVE
if (*in == '-') {
a->sign = MP_NEG;
@ -12648,8 +12683,6 @@ static int _sp_read_radix_10(sp_int* a, const char* in)
in++;
}
a->dp[0] = 0;
a->used = 0;
len = (int)XSTRLEN(in);
for (i = 0; i < len; i++) {
ch = in[i];
@ -12667,6 +12700,11 @@ static int _sp_read_radix_10(sp_int* a, const char* in)
_sp_mul_d(a, 10, a, 0);
(void)_sp_add_d(a, ch, a);
}
#ifdef WOLFSSL_SP_INT_NEGATIVE
if ((err == MP_OKAY) && sp_iszero(a)) {
a->sign = MP_ZPOS;
}
#endif
return err;
}

4
wolfcrypt/src/wolfmath.c
View File

@ -121,6 +121,10 @@ int mp_cond_copy(mp_int* a, int copy, mp_int* b)
b->dp[i] ^= (get_digit(a, i) ^ get_digit(b, i)) & mask;
}
b->used ^= (a->used ^ b->used) & (int)mask;
#if (!defined(WOLFSSL_SP_MATH) && !defined(WOLFSSL_SP_MATH_ALL)) || \
defined(WOLFSSL_SP_INT_NEGATIVE)
b->sign ^= (a->sign ^ b->sign) & (int)mask;
#endif
}
return err;

35
wolfssl/wolfcrypt/sp_int.h
View File

@ -500,6 +500,8 @@ typedef struct sp_ecc_ctx {
* @return 0 when not zero.
*/
#define sp_iszero(a) ((a)->used == 0)
#ifndef WOLFSSL_SP_INT_NEGATIVE
/* Returns whether multi-precision number has the value one.
*
* Assumes a is not NULL.
@ -509,6 +511,20 @@ typedef struct sp_ecc_ctx {
* @return 0 when not one.
*/
#define sp_isone(a) (((a)->used == 1) && ((a)->dp[0] == 1))
#else
/* Returns whether multi-precision number has the value of positive one.
*
* Assumes a is not NULL.
*
* @param [in] a SP integer to check.
* @return 1 when one.
* @return 0 when not one.
*/
#define sp_isone(a) \
(((a)->used == 1) && ((a)->dp[0] == 1) && ((a)->sign == MP_ZPOS))
#endif
#ifndef WOLFSSL_SP_INT_NEGATIVE
/* Returns whether multi-precision number has the value 'd'.
*
* Assumes a is not NULL.
@ -518,7 +534,23 @@ typedef struct sp_ecc_ctx {
* @return 1 when one.
* @return 0 when not one.
*/
#define sp_isword(a, d) (((a)->used == 1) && ((a)->dp[0] == d))
#define sp_isword(a, d) \
((((d) == 0) && sp_iszero(a)) || (((a)->used == 1) && ((a)->dp[0] == (d))))
#else
/* Returns whether multi-precision number has the value 'd'.
*
* Assumes a is not NULL.
*
* @param [in] a SP integer to check.
* @param [in] d SP integer digit.
* @return 1 when one.
* @return 0 when not one.
*/
#define sp_isword(a, d) \
((((d) == 0) && sp_iszero(a)) || \
(((a)->used == 1) && ((a)->dp[0] == (d)) && ((a)->sign == MP_ZPOS)))
#endif
#ifndef WOLFSSL_SP_INT_NEGATIVE
/* Calculate the absolute value of the multi-precision number.
*
@ -552,6 +584,7 @@ typedef struct sp_ecc_ctx {
*/
#define sp_isneg(a) ((a)->sign == MP_NEG)
#endif
/* Updates the used count to exclude leading zeros.
*
* Assumes a is not NULL.