kadmind frees invalid pointer [MITKRB5-SA-2011-004 CVE-2011-0285]

back-port r24878 for 1.8-branch

 ------------------------------------------------------------------------
 r24878 | tlyu | 2011-04-13 14:43:37 -0400 (Wed, 13 Apr 2011) | 11 lines

 ticket: 6899
 tags: pullup
 target_version: 1.9.1

 Fix the sole case in process_chpw_request() where a return could occur
 without allocating the data pointer in the response.  This prevents a
 later free() of an invalid pointer in kill_tcp_or_rpc_connection().

 Also initialize rep->data to NULL in process_chpw_request() and clean
 up *response in dispatch() as an additional precaution.

ticket: 6900
status: resolved
version_fixed: 1.8.4

git-svn-id: svn://anonsvn.mit.edu/krb5/branches/krb5-1-8@24880 dc483132-0cff-0310-8789-dd5450dbe970

diff --git a/src/kadmin/server/network.c b/src/kadmin/server/network.c
index c8ce4f1eb37a117d67c58d60dba00dbc187c5edb..bb911ffb0a35b5aa39820f15916480385415303e 100644 (file)
--- a/src/kadmin/server/network.c
+++ b/src/kadmin/server/network.c
@@ -1384,6 +1384,10 @@ cleanup:
     if (local_kaddrs != NULL)
         krb5_free_addresses(server_handle->context, local_kaddrs);
 
+    if ((*response)->data == NULL) {
+        free(*response);
+        *response = NULL;
+    }
     krb5_kt_close(server_handle->context, kt);
 
     return ret;

diff --git a/src/kadmin/server/schpw.c b/src/kadmin/server/schpw.c
index c1b22173250a0edd06a9480d3e78ef82866e303b..992b55ff4f5619433564692c1ea7429e5c549ff2 100644 (file)
--- a/src/kadmin/server/schpw.c
+++ b/src/kadmin/server/schpw.c
@@ -74,8 +74,13 @@ process_chpw_request(context, server_handle, realm, keytab,
     plen = (*ptr++ & 0xff);
     plen = (plen<<8) | (*ptr++ & 0xff);
 
-    if (plen != req->length)
-        return(KRB5KRB_AP_ERR_MODIFIED);
+    if (plen != req->length) {
+        ret = KRB5KRB_AP_ERR_MODIFIED;
+        numresult = KRB5_KPASSWD_MALFORMED;
+        strlcpy(strresult, "Request length was inconsistent",
+                sizeof(strresult));
+        goto chpwfail;
+    }
 
     /* verify version number */