From 5196926ac01177c36eab5ba2276b749c4d2bc256 Mon Sep 17 00:00:00 2001
From: Johan Danielsson <joda@pdc.kth.se>
Date: Fri, 27 Aug 1999 09:03:41 +0000
Subject: [PATCH] (rr13): handle zero length bit strings

git-svn-id: svn://svn.h5l.se/heimdal/trunk/heimdal@6880 ec53bebd-3082-4978-b11e-865c3cabbd6b
---
 lib/krb5/n-fold.c | 60 +++++++++++++++++++++++++----------------------
 1 file changed, 32 insertions(+), 28 deletions(-)

diff --git a/lib/krb5/n-fold.c b/lib/krb5/n-fold.c
index 52871b234..99fc33a37 100644
--- a/lib/krb5/n-fold.c
+++ b/lib/krb5/n-fold.c
@@ -40,37 +40,41 @@ rr13(unsigned char *buf, size_t len)
     unsigned char *tmp;
     int bytes = (len + 7) / 8;
     int i;
-    const int bits = 13 % len;
-    const int lbit = len % 8;
+    if(len == 0)
+	return;
+    {
+	const int bits = 13 % len;
+	const int lbit = len % 8;
     
-    tmp = malloc(bytes);
-    memcpy(tmp, buf, bytes);
-    if(lbit) {
-	/* pad final byte with inital bits */
-	tmp[bytes - 1] &= 0xff << (8 - lbit);
-	for(i = lbit; i < 8; i += len)
-	    tmp[bytes - 1] |= buf[0] >> i;
-    }
-    for(i = 0; i < bytes; i++) {
-	int bb;
-	int b1, s1, b2, s2;
-	/* calculate first bit position of this byte */
-	bb = 8 * i - bits;
-	while(bb < 0)
-	    bb += len;
-	/* byte offset and shift count */
-	b1 = bb / 8;
-	s1 = bb % 8;
+	tmp = malloc(bytes);
+	memcpy(tmp, buf, bytes);
+	if(lbit) {
+	    /* pad final byte with inital bits */
+	    tmp[bytes - 1] &= 0xff << (8 - lbit);
+	    for(i = lbit; i < 8; i += len)
+		tmp[bytes - 1] |= buf[0] >> i;
+	}
+	for(i = 0; i < bytes; i++) {
+	    int bb;
+	    int b1, s1, b2, s2;
+	    /* calculate first bit position of this byte */
+	    bb = 8 * i - bits;
+	    while(bb < 0)
+		bb += len;
+	    /* byte offset and shift count */
+	    b1 = bb / 8;
+	    s1 = bb % 8;
 	
-	if(bb + 8 > bytes * 8) 
-	    /* watch for wraparound */
-	    s2 = (len + 8 - s1) % 8;
-	else 
-	    s2 = 8 - s1;
-	b2 = (b1 + 1) % bytes;
-	buf[i] = (tmp[b1] << s1) | (tmp[b2] >> s2);
+	    if(bb + 8 > bytes * 8) 
+		/* watch for wraparound */
+		s2 = (len + 8 - s1) % 8;
+	    else 
+		s2 = 8 - s1;
+	    b2 = (b1 + 1) % bytes;
+	    buf[i] = (tmp[b1] << s1) | (tmp[b2] >> s2);
+	}
+	free(tmp);
     }
-    free(tmp);
 }
 
 /* Add `b' to `a', both beeing one's complement numbers. */