adding zephyr-im master branch

lib/ZCkAuth.c

@@ -0,0 +1,67 @@
+/* This file is part of the Project Athena Zephyr Notification System.
+ * It contains source for the ZCheckAuthentication function.
+ *
+ *	Created by:	Robert French
+ *
+ *	$Id$
+ *
+ *	Copyright (c) 1987,1991 by the Massachusetts Institute of Technology.
+ *	For copying and distribution information, see the file
+ *	"mit-copyright.h". 
+ */
+
+#ifndef lint
+static const char rcsid_ZCheckAuthentication_c[] =
+    "$Id$";
+#endif
+
+#include <internal.h>
+
+#if defined(HAVE_KRB5) && !HAVE_KRB5_FREE_DATA
+#define krb5_free_data(ctx, dat) free((dat)->data)
+#endif
+
+/* Check authentication of the notice.
+   If it looks authentic but fails the Kerberos check, return -1.
+   If it looks authentic and passes the Kerberos check, return 1.
+   If it doesn't look authentic, return 0
+
+   When not using Kerberos, return true if the notice claims to be authentic.
+   Only used by clients; the server uses its own routine.
+ */
+Code_t
+ZCheckAuthentication(ZNotice_t *notice,
+		     struct sockaddr_in *from)
+{
+#if defined(HAVE_KRB4) && !defined(HAVE_KRB5)
+    int result;
+    ZChecksum_t our_checksum;
+    C_Block *session;
+    CREDENTIALS cred;
+
+    /* If the value is already known, return it. */
+    if (notice->z_checked_auth != ZAUTH_UNSET)
+	return (notice->z_checked_auth);
+
+    if (!notice->z_auth)
+	return (ZAUTH_NO);
+
+    if ((result = krb_get_cred(SERVER_SERVICE, SERVER_INSTANCE, 
+			       __Zephyr_realm, &cred)) != 0)
+	return (ZAUTH_NO);
+
+    session = (C_Block *)cred.session;
+
+    our_checksum = des_quad_cksum((unsigned char *)notice->z_packet,
+				  NULL, 
+				  notice->z_default_format+
+				  strlen(notice->z_default_format) + 1
+				  - notice->z_packet,
+				  0, session);
+
+    /* if mismatched checksum, then the packet was corrupted */
+    return ((our_checksum == notice->z_checksum) ? ZAUTH_YES : ZAUTH_FAILED);
+#else
+    return ZCheckZcodeAuthentication(notice, from);
+#endif
+}