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

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This commit is contained in:
Andy Polyakov 2011-10-17 23:35:00 +00:00
parent 8329e2e776
commit 78f288d5c9
1 changed files with 6 additions and 6 deletions
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12
crypto/bn/bn_mont.c
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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 */ /* clear the top words of T */
#if 1 #if 1
for (i=r->top; i<max; i++) /* memset? XXX */ for (i=r->top; i<max; i++) /* memset? XXX */
r->d[i]=0; rp[i]=0;
#else #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 #endif
r->top=max; r->top=max;
@ -225,10 +225,10 @@ static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont)
#else #else
v=bn_mul_add_words(rp,np,nl,(rp[0]*n0)&BN_MASK2); v=bn_mul_add_words(rp,np,nl,(rp[0]*n0)&BN_MASK2);
#endif #endif
if ((rp[nl] = (rp[nl]+v+carry)&BN_MASK2) < v) v = (v+carry+rp[nl])&BN_MASK2;
carry = 1; carry |= (v != rp[nl]);
else carry &= (v <= rp[nl]);
carry = 0; rp[nl]=v;
} }
if (bn_wexpand(ret,nl) == NULL) return(0); if (bn_wexpand(ret,nl) == NULL) return(0);