svn rev #23677: trunk/src/lib/kdb/

[ghudson@MIT.EDU]

http://src.mit.edu/fisheye/changelog/krb5/?cs=23677
Commit By: ghudson
Log Message:
ticket: 6652
subject: Make decryption of master key list more robust
target_version: 1.8
tags: pullup

krb5_def_fetch_mkey_list was incorrectly filtering mkey_aux entries
when searching the list for an entry which can be decrypted with the
stashed master key.  This bug was masked in most cases by the mkvno
heuristic.

Remove the mkvno heuristic, since performance is not an issue for this
rarely-performed operation, and remove the incorrect enctype
comparison in the brute-force search.



Changed Files:
U   trunk/src/lib/kdb/kdb_default.c
Modified: trunk/src/lib/kdb/kdb_default.c
===================================================================
--- trunk/src/lib/kdb/kdb_default.c	2010-01-28 21:39:31 UTC (rev 23676)
+++ trunk/src/lib/kdb/kdb_default.c	2010-01-29 01:22:17 UTC (rev 23677)
@@ -542,49 +542,25 @@
     }
 
     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) {
+        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 (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;
-            }
+        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;
         }
     }