CFB DES sync-up with FIPS branch.

1 files changed, 47 insertions, 39 deletions

diff --git a/crypto/des/cfb_enc.c b/crypto/des/cfb_enc.c
index 136efba95b..225410efbe 100644
--- a/crypto/des/cfb_enc.c
+++ b/crypto/des/cfb_enc.c
@@ -65,32 +65,20 @@
  * the second.  The second 12 bits will come from the 3rd and half the 4th
  * byte.
  */
+/* Until Aug 1 2003 this function did not correctly implement CFB-r, so it
+ * will not be compatible with any encryption prior to that date. Ben. */
 void DES_cfb_encrypt(const unsigned char *in, unsigned char *out, int numbits,
-		     long length, DES_key_schedule *schedule, DES_cblock *ivec, int enc)
+		     long length, DES_key_schedule *schedule, DES_cblock *ivec,
+		     int enc)
 	{
-	register DES_LONG d0,d1,v0,v1,n=(numbits+7)/8;
-	register DES_LONG mask0,mask1;
+	register DES_LONG d0,d1,v0,v1;
 	register unsigned long l=length;
-	register int num=numbits;
+	register int num=numbits,n=(numbits+7)/8,i;
 	DES_LONG ti[2];
 	unsigned char *iv;
+	unsigned char ovec[16];
 
 	if (num > 64) return;
-	if (num > 32)
-		{
-		mask0=0xffffffffL;
-		if (num == 64)
-			mask1=mask0;
-		else	mask1=(1L<<(num-32))-1;
-		}
-	else
-		{
-		if (num == 32)
-			mask0=0xffffffffL;
-		else	mask0=(1L<<num)-1;
-		mask1=0x00000000L;
-		}
-
 	iv = &(*ivec)[0];
 	c2l(iv,v0);
 	c2l(iv,v1);
@@ -104,8 +92,8 @@ void DES_cfb_encrypt(const unsigned char *in, unsigned char *out, int numbits,
 			DES_encrypt1((DES_LONG *)ti,schedule,DES_ENCRYPT);
 			c2ln(in,d0,d1,n);
 			in+=n;
-			d0=(d0^ti[0])&mask0;
-			d1=(d1^ti[1])&mask1;
+			d0^=ti[0];
+			d1^=ti[1];
 			l2cn(d0,d1,out,n);
 			out+=n;
 			/* 30-08-94 - eay - changed because l>>32 and
@@ -114,15 +102,25 @@ void DES_cfb_encrypt(const unsigned char *in, unsigned char *out, int numbits,
 				{ v0=v1; v1=d0; }
 			else if (num == 64)
 				{ v0=d0; v1=d1; }
-			else if (num > 32) /* && num != 64 */
-				{
-				v0=((v1>>(num-32))|(d0<<(64-num)))&0xffffffffL;
-				v1=((d0>>(num-32))|(d1<<(64-num)))&0xffffffffL;
-				}
-			else /* num < 32 */
+			else
 				{
-				v0=((v0>>num)|(v1<<(32-num)))&0xffffffffL;
-				v1=((v1>>num)|(d0<<(32-num)))&0xffffffffL;
+				iv=&ovec[0];
+				l2c(v0,iv);
+				l2c(v1,iv);
+				l2c(d0,iv);
+				l2c(d1,iv);
+				/* shift ovec left most of the bits... */
+				memmove(ovec,ovec+num/8,8+(num%8 ? 1 : 0));
+				/* now the remaining bits */
+				if(num%8 != 0)
+					for(i=0 ; i < 8 ; ++i)
+						{
+						ovec[i]<<=num%8;
+						ovec[i]|=ovec[i+1]>>(8-num%8);
+						}
+				iv=&ovec[0];
+				c2l(iv,v0);
+				c2l(iv,v1);
 				}
 			}
 		}
@@ -142,18 +140,28 @@ void DES_cfb_encrypt(const unsigned char *in, unsigned char *out, int numbits,
 				{ v0=v1; v1=d0; }
 			else if (num == 64)
 				{ v0=d0; v1=d1; }
-			else if (num > 32) /* && num != 64 */
-				{
-				v0=((v1>>(num-32))|(d0<<(64-num)))&0xffffffffL;
-				v1=((d0>>(num-32))|(d1<<(64-num)))&0xffffffffL;
-				}
-			else /* num < 32 */
+			else
 				{
-				v0=((v0>>num)|(v1<<(32-num)))&0xffffffffL;
-				v1=((v1>>num)|(d0<<(32-num)))&0xffffffffL;
+				iv=&ovec[0];
+				l2c(v0,iv);
+				l2c(v1,iv);
+				l2c(d0,iv);
+				l2c(d1,iv);
+				/* shift ovec left most of the bits... */
+				memmove(ovec,ovec+num/8,8+(num%8 ? 1 : 0));
+				/* now the remaining bits */
+				if(num%8 != 0)
+					for(i=0 ; i < 8 ; ++i)
+						{
+						ovec[i]<<=num%8;
+						ovec[i]|=ovec[i+1]>>(8-num%8);
+						}
+				iv=&ovec[0];
+				c2l(iv,v0);
+				c2l(iv,v1);
 				}
-			d0=(d0^ti[0])&mask0;
-			d1=(d1^ti[1])&mask1;
+			d0^=ti[0];
+			d1^=ti[1];
 			l2cn(d0,d1,out,n);
 			out+=n;
 			}