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Fix SP int size of result checks 

sp_lshb: Only put values in extra word id necessary
pull/3097/head
Sean Parkinson 2020-07-02 08:57:04 +10:00
parent b6aaedd3b4
commit 0e79943a5c
1 changed files with 23 additions and 10 deletions
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33
wolfcrypt/src/sp_int.c
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@ -180,7 +180,8 @@ int sp_read_unsigned_bin(sp_int* a, const byte* in, int inSz)
int err = MP_OKAY;
int i, j = 0, k;
if (inSz > SP_INT_DIGITS * (int)sizeof(a->dp[0])) {
/* Extra digit added to SP_INT_DIGITS to be used in calculations. */
if (inSz > (SP_INT_DIGITS - 1) * (int)sizeof(a->dp[0])) {
err = MP_VAL;
}
@ -592,20 +593,26 @@ int sp_cmp_d(sp_int *a, sp_int_digit d)
static int sp_lshb(sp_int* a, int n)
{
int i;
sp_digit v;
if (n >= SP_WORD_SIZE) {
sp_lshd(a, n / SP_WORD_SIZE);
n %= SP_WORD_SIZE;
}
if (n != 0) {
a->dp[a->used] = 0;
for (i = a->used - 1; i >= 0; i--) {
if ((n != 0) && (a->used != 0)) {
v = a->dp[a->used - 1] >> (SP_WORD_SIZE - n);
if (v != 0) {
a->dp[a->used] = v;
}
a->dp[a->used - 1] = a->dp[a->used - 1] << n;
for (i = a->used - 2; i >= 0; i--) {
a->dp[i+1] |= a->dp[i] >> (SP_WORD_SIZE - n);
a->dp[i] = a->dp[i] << n;
}
if (a->dp[a->used] != 0)
if (v != 0) {
a->used++;
}
}
return MP_OKAY;
@ -986,7 +993,9 @@ int sp_add(sp_int* a, sp_int* b, sp_int* r)
r->dp[i] = b->dp[i] + c;
c = (b->dp[i] != 0) && (r->dp[i] == 0);
}
r->dp[i] = c;
if (c != 0) {
r->dp[i] = c;
}
r->used = (int)(i + c);
return MP_OKAY;
@ -1183,7 +1192,8 @@ int sp_mul(sp_int* a, sp_int* b, sp_int* r)
sp_int tr[1];
#endif
if (a->used + b->used > SP_INT_DIGITS)
/* Need extra digit during calculation. */
if (a->used + b->used > (SP_INT_DIGITS - 1))
err = MP_VAL;
#ifdef WOLFSSL_SMALL_STACK
@ -1227,7 +1237,8 @@ static int sp_sqrmod(sp_int* a, sp_int* m, sp_int* r)
{
int err = MP_OKAY;
if (a->used * 2 > SP_INT_DIGITS)
/* Need extra digit during calculation. */
if (a->used * 2 > (SP_INT_DIGITS - 1))
err = MP_VAL;
if (err == MP_OKAY)
@ -1257,7 +1268,8 @@ int sp_mulmod(sp_int* a, sp_int* b, sp_int* m, sp_int* r)
sp_int t[1];
#endif
if (a->used + b->used > SP_INT_DIGITS)
/* Need extra digit during calculation. */
if (a->used + b->used > (SP_INT_DIGITS - 1))
err = MP_VAL;
#ifdef WOLFSSL_SMALL_STACK
@ -1627,7 +1639,8 @@ int sp_exptmod(sp_int* b, sp_int* e, sp_int* m, sp_int* r)
sp_set(r, 0);
done = 1;
}
else if (m->used * 2 > SP_INT_DIGITS) {
/* Ensure SP integers have space for intermediate values. */
else if (m->used * 2 > (SP_INT_DIGITS - 1)) {
err = BAD_FUNC_ARG;
}