Master Key Migration Project

Commit for the Master Key Migration Project.
http://k5wiki.kerberos.org/wiki/Projects/Master_Key_Migration

This commit provides the ability to add a new master key (with an
enctype differing from the current master key) to the master key
principal and stash file and then migrate the encryption of existing
principals long term keys to use the new master key.  In addition
deletion of master keys is provided. 

ticket: 6354

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@21844 dc483132-0cff-0310-8789-dd5450dbe970

1 files changed, 204 insertions, 16 deletions

diff --git a/src/lib/kdb/kdb_default.c b/src/lib/kdb/kdb_default.c
index f173e127df..df87916242 100644
--- a/src/lib/kdb/kdb_default.c
+++ b/src/lib/kdb/kdb_default.c
@@ -1,7 +1,7 @@
 /*
  * lib/kdb/kdb_helper.c
  *
- * Copyright 1995, 2008 by the Massachusetts Institute of Technology. 
+ * Copyright 1995, 2009 by the Massachusetts Institute of Technology. 
  * All Rights Reserved.
  *
  * Export of this software from the United States of America may
@@ -25,6 +25,11 @@
  * 
  */
 
+/*
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
 #include "k5-int.h"
 #include "kdb.h"
 #include <string.h>
@@ -133,12 +138,11 @@ krb5_dbe_def_search_enctype(kcontext, dbentp, start, ktype, stype, kvno, kdatap)
 #endif
 
 krb5_error_code
-krb5_def_store_mkey(krb5_context   context,
-                    char           *keyfile,
-                    krb5_principal mname,
-                    krb5_kvno      kvno,
-                    krb5_keyblock  *key,
-                    char           *master_pwd)
+krb5_def_store_mkey_list(krb5_context       context,
+			 char               *keyfile,
+			 krb5_principal     mname,
+			 krb5_keylist_node  *keylist,
+			 char               *master_pwd)
 {
     krb5_error_code retval = 0;
     char defkeyfile[MAXPATHLEN+1];
@@ -199,12 +203,17 @@ krb5_def_store_mkey(krb5_context   context,
     if (retval != 0)
         goto out;
 
-    memset((char *) &new_entry, 0, sizeof(new_entry));
-    new_entry.principal = mname;
-    new_entry.key = *key;
-    new_entry.vno = kvno;
+    while (keylist && !retval) {
+        memset((char *) &new_entry, 0, sizeof(new_entry));
+        new_entry.principal = mname;
+        new_entry.key = keylist->keyblock;
+        new_entry.vno = keylist->kvno;
+
+        retval = krb5_kt_add_entry(context, kt, &new_entry);
+        keylist = keylist->next;
+    }
+    krb5_kt_close(context, kt);
 
-    retval = krb5_kt_add_entry(context, kt, &new_entry);
     if (retval != 0) {
         /* delete tmp keyfile if it exists and an error occurrs */
         if (stat(keyfile, &stb) >= 0)
@@ -222,12 +231,27 @@ krb5_def_store_mkey(krb5_context   context,
 out:
     if (tmp_ktname != NULL)
         free(tmp_ktname);
-    if (kt)
-	krb5_kt_close(context, kt);
 
     return retval;
 }
 
+krb5_error_code
+krb5_def_store_mkey(krb5_context   context,
+                    char           *keyfile,
+                    krb5_principal mname,
+                    krb5_kvno      kvno,
+                    krb5_keyblock  *key,
+                    char           *master_pwd)
+{
+    krb5_keylist_node list;
+
+    list.kvno = kvno;
+    list.keyblock = *key;
+    list.next = NULL;
+    return krb5_def_store_mkey_list(context, keyfile, mname, &list,
+				    master_pwd);
+}
+
 static krb5_error_code
 krb5_db_def_fetch_mkey_stash(krb5_context   context,
 			     const char *keyfile,
@@ -288,7 +312,7 @@ krb5_db_def_fetch_mkey_stash(krb5_context   context,
     if (fread((krb5_pointer) key->contents, sizeof(key->contents[0]),
 					    key->length, kf) != key->length) {
 	retval = KRB5_KDB_CANTREAD_STORED;
-	memset(key->contents, 0,  key->length);
+	zap(key->contents, key->length);
 	free(key->contents);
 	key->contents = 0;
     } else
@@ -421,6 +445,9 @@ krb5_db_def_fetch_mkey(krb5_context   context,
     }
 }
 
+/*
+ * Note, this verifies that the input mkey is currently protecting all the mkeys
+ */
 krb5_error_code
 krb5_def_verify_master_key(krb5_context    context,
                            krb5_principal  mprinc,
@@ -468,13 +495,160 @@ krb5_def_verify_master_key(krb5_context    context,
             kvno, master_entry.key_data->key_data_kvno);
     }
 
-    memset((char *)tempkey.contents, 0, tempkey.length);
+    zap((char *)tempkey.contents, tempkey.length);
     free(tempkey.contents);
     krb5_db_free_principal(context, &master_entry, nprinc);
     
     return retval;
 }
 
+krb5_error_code
+krb5_def_fetch_mkey_list(krb5_context        context,
+                       krb5_principal        mprinc,
+                       const krb5_keyblock  *mkey,
+                       krb5_kvno             mkvno,
+                       krb5_keylist_node  **mkeys_list)
+{
+    krb5_error_code retval;
+    krb5_db_entry master_entry;
+    int nprinc;
+    krb5_boolean more, found_key = FALSE;
+    krb5_keyblock cur_mkey;
+    krb5_keylist_node *mkey_list_head = NULL, **mkey_list_node;
+    krb5_key_data *key_data;
+    krb5_mkey_aux_node	*mkey_aux_data_list, *aux_data_entry;
+    int i;
+
+    if (mkeys_list == NULL)
+        return (EINVAL);
+
+    memset(&cur_mkey, 0, sizeof(cur_mkey));
+
+    nprinc = 1;
+    if ((retval = krb5_db_get_principal(context, mprinc,
+                                        &master_entry, &nprinc, &more)))
+        return (retval);
+
+    if (nprinc != 1) {
+        if (nprinc)
+            krb5_db_free_principal(context, &master_entry, nprinc);
+        return(KRB5_KDB_NOMASTERKEY);
+    } else if (more) {
+        krb5_db_free_principal(context, &master_entry, nprinc);
+        return (KRB5KDC_ERR_PRINCIPAL_NOT_UNIQUE);
+    }
+
+    /*
+     * Check if the input mkey is the latest key and if it isn't then find the
+     * latest mkey.
+     */
+
+    if (mkey->enctype == master_entry.key_data[0].key_data_type[0]) {
+        if (krb5_dbekd_decrypt_key_data(context, mkey,
+                                        &master_entry.key_data[0],
+                                        &cur_mkey, NULL) == 0) {
+            found_key = TRUE;
+        }
+    }
+
+    if (!found_key) {
+        /*
+         * Note the mkvno may provide a hint as to which mkey_aux tuple to
+         * decrypt.
+         */
+        if ((retval = krb5_dbe_lookup_mkey_aux(context, &master_entry,
+                                               &mkey_aux_data_list)))
+            goto clean_n_exit;
+
+        /* mkvno may be 0 in some cases like keyboard and should be ignored */
+        if (mkvno != 0) {
+            /* for performance sake, try decrypting with matching kvno */
+            for (aux_data_entry = mkey_aux_data_list; aux_data_entry != NULL;
+                 aux_data_entry = aux_data_entry->next) {
+
+                if (aux_data_entry->mkey_kvno == mkvno) {
+                    if (krb5_dbekd_decrypt_key_data(context, mkey,
+                                                    &aux_data_entry->latest_mkey,
+                                                    &cur_mkey, NULL) == 0) {
+                        found_key = TRUE;
+                        break;
+                    }
+                }
+            }
+        }
+        if (!found_key) {
+            /* given the importance of acquiring the latest mkey, try brute force */
+            for (aux_data_entry = mkey_aux_data_list; aux_data_entry != NULL;
+                 aux_data_entry = aux_data_entry->next) {
+
+                if (mkey->enctype == aux_data_entry->latest_mkey.key_data_type[0] &&
+                    (krb5_dbekd_decrypt_key_data(context, mkey,
+                                                 &aux_data_entry->latest_mkey,
+                                                 &cur_mkey, NULL) == 0)) {
+                    found_key = TRUE;
+                    break;
+                }
+            }
+            if (found_key != TRUE) {
+                krb5_set_error_message (context, KRB5_KDB_BADMASTERKEY,
+                    "Unable to decrypt latest master key with the provided master key\n");
+                retval = KRB5_KDB_BADMASTERKEY;
+                goto clean_n_exit;
+            }
+        }
+    }
+
+    /*
+     * Extract all the mkeys from master_entry using the most current mkey and
+     * create a mkey list for the mkeys field in kdc_realm_t. 
+     */
+
+    mkey_list_head = (krb5_keylist_node *) malloc(sizeof(krb5_keylist_node));
+    if (mkey_list_head == NULL) {
+        retval = ENOMEM;
+        goto clean_n_exit;
+    }
+
+    memset(mkey_list_head, 0, sizeof(krb5_keylist_node));
+
+    /* Set mkey_list_head to the current mkey as an optimization. */
+    /* mkvno may not be latest so ... */
+    mkey_list_head->kvno = master_entry.key_data[0].key_data_kvno;
+    /* this is the latest clear mkey (avoids a redundant decrypt) */
+    mkey_list_head->keyblock = cur_mkey;
+
+    /* loop through any other master keys creating a list of krb5_keylist_nodes */
+    mkey_list_node = &mkey_list_head->next;
+    for (i = 1; i < master_entry.n_key_data; i++) {
+        if (*mkey_list_node == NULL) {
+            /* *mkey_list_node points to next field of previous node */
+            *mkey_list_node = (krb5_keylist_node *) malloc(sizeof(krb5_keylist_node));
+            if (*mkey_list_node == NULL) {
+                retval = ENOMEM;
+                goto clean_n_exit;
+            }
+            memset(*mkey_list_node, 0, sizeof(krb5_keylist_node));
+        }
+        key_data = &master_entry.key_data[i];
+        retval = krb5_dbekd_decrypt_key_data(context, &cur_mkey,
+                                             key_data,
+                                             &((*mkey_list_node)->keyblock),
+                                             NULL);
+        if (retval)
+            goto clean_n_exit;
+
+        (*mkey_list_node)->kvno = key_data->key_data_kvno;
+        mkey_list_node = &((*mkey_list_node)->next);
+    }
+
+    *mkeys_list = mkey_list_head;
+
+clean_n_exit:
+    krb5_db_free_principal(context, &master_entry, nprinc);
+    if (retval != 0)
+        krb5_dbe_free_key_list(context, mkey_list_head);
+    return retval;
+}
 
 krb5_error_code kdb_def_set_mkey ( krb5_context kcontext,
 				   char *pwd,
@@ -491,6 +665,20 @@ krb5_error_code kdb_def_get_mkey ( krb5_context kcontext,
     return 0;
 }
 
+krb5_error_code kdb_def_set_mkey_list ( krb5_context kcontext,
+				        krb5_keylist_node *keylist )
+{
+    /* printf("default set master key\n"); */
+    return 0;
+}
+
+krb5_error_code kdb_def_get_mkey_list ( krb5_context kcontext,
+				        krb5_keylist_node **keylist )
+{
+    /* printf("default get master key\n"); */
+    return 0;
+}
+
 krb5_error_code krb5_def_promote_db (krb5_context kcontext,
 				     char *s, char **args)
 {