BUG#34788 - malformed federated connection url is not handled

            correctly - crashes server !

Creating federated table with connect string containing empty
(zero-length) host name and port is evaluated as 0 (port is
incorrect, omitted or 0) crashes server.

This happens because federated calls strcmp() with NULL pointer.

Fixed by avoiding strcmp() call if hostname is set to NULL.


mysql-test/r/federated.result:
  A test case for BUG#34788.
mysql-test/t/federated.test:
  A test case for BUG#34788.
sql/ha_federated.cc:
  Fixed that parse_url() may call strcmp() with NULL pointer.

1 files changed, 8 insertions, 1 deletions

diff --git a/sql/ha_federated.cc b/sql/ha_federated.cc
index c0743bd6c9a..a5e4714c53a 100644
--- a/sql/ha_federated.cc
+++ b/sql/ha_federated.cc
@@ -643,12 +643,19 @@ static int parse_url(FEDERATED_SHARE *share, TABLE *table,
   if ((strchr(share->table_name, '/')))
     goto error;
 
+  /*
+    If hostname is omitted, we set it to NULL. According to
+    mysql_real_connect() manual:
+    The value of host may be either a hostname or an IP address.
+    If host is NULL or the string "localhost", a connection to the
+    local host is assumed.
+  */
   if (share->hostname[0] == '\0')
     share->hostname= NULL;
 
   if (!share->port)
   {
-    if (strcmp(share->hostname, my_localhost) == 0)
+    if (!share->hostname || strcmp(share->hostname, my_localhost) == 0)
       share->socket= my_strdup(MYSQL_UNIX_ADDR, MYF(0));
     else
       share->port= MYSQL_PORT;