Implement ZDumpSession and ZLoadSession

This is unlikely to ever get merged, but it'll be handy for roost.

3 files changed, 143 insertions, 1 deletions

diff --git a/h/zephyr/zephyr.h b/h/zephyr/zephyr.h
index 28baa7f..06cf541 100644
--- a/h/zephyr/zephyr.h
+++ b/h/zephyr/zephyr.h
@@ -259,6 +259,8 @@ Code_t ZTransliterate(char *in, int inlen, char *inset, char *outset, char **out
 void Z_debug(const char *, ...);
 #endif
 char *ZExpandRealm(char *realm);
+Code_t ZDumpSession(char **buffer, int *ret_len);
+Code_t ZLoadSession(char *buffer, int len);
 
 /* Compatibility */
 #define	ZNewLocateUser ZLocateUser
diff --git a/lib/Makefile.in b/lib/Makefile.in
index 79c8173..d76f2a9 100644
--- a/lib/Makefile.in
+++ b/lib/Makefile.in
@@ -41,7 +41,8 @@ OBJS =	zephyr_err.lo ZAsyncLocate.lo ZCkAuth.lo ZCkIfNot.lo ZClosePort.lo \
 	ZRecvNot.lo ZRecvPkt.lo ZRetSubs.lo ZSendList.lo ZSendNot.lo \
 	ZSendPkt.lo ZSendRaw.lo ZSendRLst.lo ZSetDest.lo ZSetFD.lo ZSetSrv.lo \
 	ZSubs.lo ZVariables.lo ZWait4Not.lo Zinternal.lo ZMakeZcode.lo \
-	ZReadZcode.lo ZCkZAut.lo quad_cksum.lo charset.lo ZExpnRlm.lo
+	ZReadZcode.lo ZCkZAut.lo quad_cksum.lo charset.lo ZExpnRlm.lo \
+	ZDumpSession.lo
 
 .SUFFIXES: .lo
 
diff --git a/lib/ZDumpSession.c b/lib/ZDumpSession.c
new file mode 100644
index 0000000..f4dfc76
--- /dev/null
+++ b/lib/ZDumpSession.c
@@ -0,0 +1,139 @@
+/* This file is part of the Project Athena Zephyr Notification System.
+ * It contains source for the session dump and restore function.
+ *
+ *	Created by:	David Benjamin
+ *
+ *	$Id$
+ *
+ *	Copyright (c) 2013 by the Massachusetts Institute of Technology.
+ *	For copying and distribution information, see the file
+ *	"mit-copyright.h".
+ */
+
+#ifndef lint
+static const char rcsid_ZDumpSession_c[] = "$Id$";
+#endif
+
+#include <internal.h>
+
+#define SESSION_VERSION 1
+
+Code_t
+ZDumpSession(char **buffer,
+             int *ret_len)
+{
+#ifdef HAVE_KRB5
+    struct _Z_SessionKey *key;
+    uint32_t num_keys = 0;
+    int i;
+#endif
+    char *ptr;
+    int len;
+
+    /*
+     * We serialize the port number and all keys. All numbers are
+     * stored in big-endian. Byte strings are prefixed with a 32-bit
+     * length. First field is 16-bit version number. Keys are stored
+     * in reverse.
+     */
+
+    len = 2 + 2;  /* version, port number */
+#ifdef HAVE_KRB5
+    len += 4;  /* num_keys */
+    for (key = Z_keys_head; key != NULL; key = key->next) {
+	num_keys++;
+	len += 4 + 4;  /* enctype, length */
+	len += key->keyblock->length;  /* contents */
+    }
+#endif
+
+    *ret_len = len;
+    if (!(*buffer = (char *) malloc((unsigned)*ret_len)))
+	return (ENOMEM);
+
+    ptr = *buffer;
+    *((uint16_t*) ptr) = htons(SESSION_VERSION); ptr += 2;
+    *((uint16_t*) ptr) = htons(__Zephyr_port); ptr += 2;
+#ifdef HAVE_KRB5
+    *((uint32_t *)ptr) = htonl(num_keys); ptr += 4;
+    for (key = Z_keys_tail; key != NULL; key = key->prev) {
+	*((uint32_t*) ptr) = htonl(key->keyblock->enctype); ptr += 4;
+	*((uint32_t*) ptr) = htonl(key->keyblock->length); ptr += 4;
+	memcpy(ptr, key->keyblock->contents, key->keyblock->length);
+	ptr += key->keyblock->length;
+    }
+#endif
+
+    return (ZERR_NONE);
+}
+
+Code_t
+ZLoadSession(char *buffer, int len)
+{
+#ifdef HAVE_KRB5
+    struct _Z_SessionKey *key;
+    uint32_t num_keys, keylength;
+    krb5_enctype enctype;
+#endif
+    int i;
+    Code_t ret;
+    uint16_t version, port;
+
+    if (len < 2) return (EINVAL);
+    version = ntohs(*((uint16_t *) buffer)); buffer += 2; len -= 2;
+    if (version != SESSION_VERSION)
+	return (EINVAL);
+
+    if (len < 2) return (EINVAL);
+    port = ntohs(*((uint16_t *) buffer)); buffer += 2; len -= 2;
+    if ((ret = ZOpenPort(&port)) != ZERR_NONE)
+	return ret;
+
+#ifdef HAVE_KRB5
+    if (len < 4) return (EINVAL);
+    num_keys = ntohl(*((uint32_t *) buffer)); buffer += 4; len -= 4;
+
+    for (i = 0; i < num_keys; i++) {
+	key = (struct _Z_SessionKey *)malloc(sizeof(struct _Z_SessionKey));
+	if (!key)
+	    return (ENOMEM);
+	if (len < 4) {
+	    free(key);
+	    return (EINVAL);
+	}
+	enctype = ntohl(*((uint32_t *) buffer)); buffer += 4; len -= 4;
+	if (len < 4) {
+	    free(key);
+	    return (EINVAL);
+	}
+	keylength = ntohl(*((uint32_t *) buffer)); buffer += 4; len -= 4;
+	if (len < keylength) {
+	    free(key);
+	    return (EINVAL);
+	}
+	ret = krb5_init_keyblock(Z_krb5_ctx, enctype, keylength, &key->keyblock);
+	if (ret) {
+	    free(key);
+	    return ret;
+	}
+	memcpy((char *)key->keyblock->contents, buffer, keylength);
+	buffer += keylength; len -= keylength;
+	/* Just set recent times. It means we might not be able to
+	   retire the keys, but that's fine. */
+	key->send_time = time(NULL);
+	key->first_use = time(NULL);
+	/* Prepend to the key list. */
+	key->prev = NULL;
+	key->next = Z_keys_head;
+	if (Z_keys_head)
+	    Z_keys_head->prev = key;
+	Z_keys_head = key;
+	if (!Z_keys_tail)
+	    Z_keys_tail = key;
+    }
+#endif
+
+    if (len)
+	return (EINVAL);
+    return (ZERR_NONE);
+}