merge new-crypto branch

git-svn-id: svn://svn.h5l.se/heimdal/trunk/heimdal@5332 ec53bebd-3082-4978-b11e-865c3cabbd6b

lib/krb5/n-fold.c

@@ -0,0 +1,88 @@
+#include "krb5_locl.h"
+
+static void
+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;
+    
+    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);
+    }
+    free(tmp);
+}
+
+/* Add `b' to `a', both beeing one's complement numbers. */
+static void
+add1(unsigned char *a, unsigned char *b, size_t len)
+{
+    int i;
+    int carry = 0;
+    for(i = len - 1; i >= 0; i--){
+	int x = a[i] + b[i] + carry;
+	carry = x > 0xff;
+	a[i] = x & 0xff;
+    }
+    for(i = len - 1; carry && i >= 0; i--){
+	int x = a[i] + carry;
+	carry = x > 0xff;
+	a[i] = carry & 0xff;
+    }
+}
+
+void
+n_fold(const void *str, size_t len, void *key, size_t size)
+{
+    /* if len < size we need at most N * len bytes, ie < 2 * size;
+       if len > size we need at most 2 * len */
+    size_t maxlen = 2 * max(size, len);
+    size_t l = 0;
+    unsigned char *tmp = malloc(maxlen);
+    unsigned char *buf = malloc(len);
+    
+    memcpy(buf, str, len);
+    memset(key, 0, size);
+    do {
+	memcpy(tmp + l, buf, len);
+	l += len;
+	rr13(buf, len * 8);
+	while(l >= size) {
+	    add1(key, tmp, size);
+	    l -= size;
+	    if(l == 0)
+		break;
+	    memmove(tmp, tmp + size, l);
+	}
+    } while(l != 0);
+    memset(buf, 0, len);
+    free(buf);
+    memset(tmp, 0, maxlen);
+    free(tmp);
+}