1 files changed, 88 insertions, 0 deletions
diff --git a/usr.sbin/xntpd/lib/authencrypt.c b/usr.sbin/xntpd/lib/authencrypt.c
new file mode 100644
index 0000000..66b5281
--- /dev/null
+++ b/usr.sbin/xntpd/lib/authencrypt.c
@@ -0,0 +1,88 @@
+/* authencrypt.c,v 3.1 1993/07/06 01:07:50 jbj Exp
+ * authencrypt - compute and encrypt the mac field in an NTP packet
+ */
+#include "ntp_stdlib.h"
+
+/*
+ * For our purposes an NTP packet looks like:
+ *
+ *	a variable amount of encrypted data, multiple of 8 bytes, followed by:
+ *	NOCRYPT_OCTETS worth of unencrypted data, followed by:
+ *	BLOCK_OCTETS worth of ciphered checksum.
+ */ 
+#define	NOCRYPT_OCTETS	4
+#define	BLOCK_OCTETS	8
+
+#define	NOCRYPT_LONGS	((NOCRYPT_OCTETS)/sizeof(U_LONG))
+#define	BLOCK_LONGS	((BLOCK_OCTETS)/sizeof(U_LONG))
+
+/*
+ * Imported from the key data base module
+ */
+extern U_LONG cache_keyid;	/* cached key ID */
+extern u_char DEScache_ekeys[];	/* cached decryption keys */
+extern u_char DESzeroekeys[];	/* zero key decryption keys */
+
+/*
+ * Stat counters from the database module
+ */
+extern U_LONG authencryptions;
+extern U_LONG authkeyuncached;
+extern U_LONG authnokey;
+
+int
+DESauthencrypt(keyno, pkt, length)
+	U_LONG keyno;
+	U_LONG *pkt;
+	int length;	/* length of encrypted portion of packet */
+{
+	register U_LONG *pd;
+	register int i;
+	register u_char *keys;
+	register int len;
+	U_LONG work[2];
+
+	authencryptions++;
+
+	if (keyno == 0) {
+		keys = DESzeroekeys;
+	} else {
+		if (keyno != cache_keyid) {
+			authkeyuncached++;
+			if (!authhavekey(keyno)) {
+				authnokey++;
+				return 0;
+			}
+		}
+		keys = DEScache_ekeys;
+	}
+
+	/*
+	 * Do the encryption.  Work our way forward in the packet, eight
+	 * bytes at a time, encrypting as we go.  Note that the byte order
+	 * issues are handled by the DES routine itself
+	 */
+	pd = pkt;
+	work[0] = work[1] = 0;
+	len = length / sizeof(U_LONG);
+
+	for (i = (len/2); i > 0; i--) {
+		work[0] ^= *pd++;
+		work[1] ^= *pd++;
+		DESauth_des(work, keys);
+	}
+
+	if (len & 0x1) {
+		work[0] ^= *pd++;
+		DESauth_des(work, keys);
+	}
+
+	/*
+	 * Space past the keyid and stick the result back in the mac field
+	 */
+	pd += NOCRYPT_LONGS;
+	*pd++ = work[0];
+	*pd = work[1];
+
+	return 4 + BLOCK_OCTETS;	/* return size of key and MAC  */
+}