bn_mont.c: get corner cases right in updated BN_from_montgomery_word.

This commit is contained in:
Andy Polyakov 2011-10-17 23:35:00 +00:00
parent 8329e2e776
commit 78f288d5c9

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@ -196,9 +196,9 @@ static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont)
/* clear the top words of T */
#if 1
for (i=r->top; i<max; i++) /* memset? XXX */
r->d[i]=0;
rp[i]=0;
#else
memset(&(r->d[r->top]),0,(max-r->top)*sizeof(BN_ULONG));
memset(&(rp[r->top]),0,(max-r->top)*sizeof(BN_ULONG));
#endif
r->top=max;
@ -225,10 +225,10 @@ static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont)
#else
v=bn_mul_add_words(rp,np,nl,(rp[0]*n0)&BN_MASK2);
#endif
if ((rp[nl] = (rp[nl]+v+carry)&BN_MASK2) < v)
carry = 1;
else
carry = 0;
v = (v+carry+rp[nl])&BN_MASK2;
carry |= (v != rp[nl]);
carry &= (v <= rp[nl]);
rp[nl]=v;
}
if (bn_wexpand(ret,nl) == NULL) return(0);