X-Git-Url: https://git.openssl.org/gitweb/?a=blobdiff_plain;f=crypto%2Fbn%2Fbn_shift.c;h=de9312dce231f5de6c03a90baf42ee867c6b6838;hb=5e428e7d0d53522e82a1eb6e418de8b7138e4cda;hp=944bf1794bc1876de012fc82d82881631011334d;hpb=7dfb0b774e6592dcbfe47015168a0ac8b44e2a17;p=openssl.git

diff --git a/crypto/bn/bn_shift.c b/crypto/bn/bn_shift.c
index 944bf1794b..de9312dce2 100644
--- a/crypto/bn/bn_shift.c
+++ b/crypto/bn/bn_shift.c
@@ -60,13 +60,14 @@
 #include "cryptlib.h"
 #include "bn_lcl.h"
 
-int BN_lshift1(r, a)
-BIGNUM *r;
-BIGNUM *a;
+int BN_lshift1(BIGNUM *r, const BIGNUM *a)
 	{
 	register BN_ULONG *ap,*rp,t,c;
 	int i;
 
+	bn_check_top(r);
+	bn_check_top(a);
+
 	if (r != a)
 		{
 		r->neg=a->neg;
@@ -91,16 +92,18 @@ BIGNUM *a;
 		*rp=1;
 		r->top++;
 		}
+	bn_check_top(r);
 	return(1);
 	}
 
-int BN_rshift1(r, a)
-BIGNUM *r;
-BIGNUM *a;
+int BN_rshift1(BIGNUM *r, const BIGNUM *a)
 	{
 	BN_ULONG *ap,*rp,t,c;
 	int i;
 
+	bn_check_top(r);
+	bn_check_top(a);
+
 	if (BN_is_zero(a))
 		{
 		BN_zero(r);
@@ -121,22 +124,23 @@ BIGNUM *a;
 		rp[i]=((t>>1)&BN_MASK2)|c;
 		c=(t&1)?BN_TBIT:0;
 		}
-	bn_fix_top(r);
+	bn_correct_top(r);
+	bn_check_top(r);
 	return(1);
 	}
 
-int BN_lshift(r, a, n)
-BIGNUM *r;
-BIGNUM *a;
-int n;
+int BN_lshift(BIGNUM *r, const BIGNUM *a, int n)
 	{
 	int i,nw,lb,rb;
 	BN_ULONG *t,*f;
 	BN_ULONG l;
 
+	bn_check_top(r);
+	bn_check_top(a);
+
 	r->neg=a->neg;
-	if (bn_wexpand(r,a->top+(n/BN_BITS2)+1) == NULL) return(0);
 	nw=n/BN_BITS2;
+	if (bn_wexpand(r,a->top+nw+1) == NULL) return(0);
 	lb=n%BN_BITS2;
 	rb=BN_BITS2-lb;
 	f=a->d;
@@ -156,23 +160,24 @@ int n;
 /*	for (i=0; i<nw; i++)
 		t[i]=0;*/
 	r->top=a->top+nw+1;
-	bn_fix_top(r);
+	bn_correct_top(r);
+	bn_check_top(r);
 	return(1);
 	}
 
-int BN_rshift(r, a, n)
-BIGNUM *r;
-BIGNUM *a;
-int n;
+int BN_rshift(BIGNUM *r, const BIGNUM *a, int n)
 	{
 	int i,j,nw,lb,rb;
 	BN_ULONG *t,*f;
 	BN_ULONG l,tmp;
 
+	bn_check_top(r);
+	bn_check_top(a);
+
 	nw=n/BN_BITS2;
 	rb=n%BN_BITS2;
 	lb=BN_BITS2-rb;
-	if (nw > a->top)
+	if (nw > a->top || a->top == 0)
 		{
 		BN_zero(r);
 		return(1);
@@ -182,6 +187,11 @@ int n;
 		r->neg=a->neg;
 		if (bn_wexpand(r,a->top-nw+1) == NULL) return(0);
 		}
+	else
+		{
+		if (n == 0)
+			return 1; /* or the copying loop will go berserk */
+		}
 
 	f= &(a->d[nw]);
 	t=r->d;
@@ -190,13 +200,13 @@ int n;
 
 	if (rb == 0)
 		{
-		for (i=j+1; i > 0; i--)
+		for (i=j; i != 0; i--)
 			*(t++)= *(f++);
 		}
 	else
 		{
 		l= *(f++);
-		for (i=1; i<j; i++)
+		for (i=j-1; i != 0; i--)
 			{
 			tmp =(l>>rb)&BN_MASK2;
 			l= *(f++);
@@ -204,7 +214,7 @@ int n;
 			}
 		*(t++) =(l>>rb)&BN_MASK2;
 		}
-	*t=0;
-	bn_fix_top(r);
+	bn_correct_top(r);
+	bn_check_top(r);
 	return(1);
 	}