Upstream/dhcp: Fix crash when switching networkssubmit/tizen/20140807.060945

Sometimes while switching network dhcp_initialize() fails because
interface is not up and hence dhcp->dhcp_client remains NULL. Here we
don't check return type of dhcp_initialize() and go on to call function
g_dhcp_client_start() and crash occurs.

Below trace is obtained when connman crashes:
connmand[19034]: Aborting (signal 11) [/usr/local/sbin/connmand]
connmand[19034]: ++++++++ backtrace ++++++++
connmand[19034]: #0  0xb7630f38 in /lib/i386-linux-gnu/libpthread.so.0
connmand[19034]: #1  0x8055a22 in debug() at client.c:0
connmand[19034]: #2  0x8058837 in g_dhcp_client_start() at polkit.c:0
connmand[19034]: #3  0x80a4772 in __connman_dhcp_start() at polkit.c:0
connmand[19034]: #4  0x8082a80 in set_connected.part.8() at network.c:0
connmand[19034]: #5  0x8082f7f in connman_network_set_connected() at
??:0
connmand[19034]: #6  0x805f921 in eth_network_connect() at ethernet.c:0
connmand[19034]: #7  0x8082dc3 in __connman_network_connect() at
polkit.c:0
connmand[19034]: #8  0x808e7e4 in __connman_service_connect() at
polkit.c:0
connmand[19034]: #9  0x808eef0 in auto_connect_service() at service.c:0
connmand[19034]: #10 0x808efde in run_auto_connect() at service.c:0
connmand[19034]: #11 0xb76cea3f in /lib/i386-linux-gnu/libglib-2.0.so.0
connmand[19034]: #12 0xb76cdd46 in /lib/i386-linux-gnu/libglib-2.0.so.0
connmand[19034]: #13 0xb76ce0e5 in /lib/i386-linux-gnu/libglib-2.0.so.0
connmand[19034]: #14 0xb76ce52b in /lib/i386-linux-gnu/libglib-2.0.so.0
connmand[19034]: #15 0x80544cd in main() at polkit.c:0
connmand[19034]: #16 0xb739b4d3 in /lib/i386-linux-gnu/libc.so.6
connmand[19034]: +++++++++++++++++++++++++++

1 files changed, 8 insertions, 2 deletions

diff --git a/src/dhcp.c b/src/dhcp.c
index 83d7dfb3..b35f15a6 100644
--- a/src/dhcp.c
+++ b/src/dhcp.c
@@ -577,6 +577,7 @@ int __connman_dhcp_start(struct connman_network *network, dhcp_cb callback)
 	struct connman_ipconfig *ipconfig;
 	const char *last_addr = NULL;
 	struct connman_dhcp *dhcp;
+	int err;
 
 	DBG("");
 
@@ -598,9 +599,14 @@ int __connman_dhcp_start(struct connman_network *network, dhcp_cb callback)
 		dhcp->network = network;
 		connman_network_ref(network);
 
-		g_hash_table_insert(network_table, network, dhcp);
+		err = dhcp_initialize(dhcp);
+		if (err < 0) {
+			connman_network_unref(network);
+			g_free(dhcp);
+			return err;
+		}
 
-		dhcp_initialize(dhcp);
+		g_hash_table_insert(network_table, network, dhcp);
 	}
 
 	dhcp->callback = callback;