Fix memleaks on interface refresh when extcap configs exists

If there are extcap interfaces present then each time the capture
interfaces list is displayed or refreshed a number of extcap related
allocations are leaked.

Valgrind reports leaks like these:

2,007 (144 direct, 1,863 indirect) bytes in 6 blocks are definitely lost in loss record 64,328 of 65,138
   at 0x4C2AB80: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
   by 0xA6D2610: g_malloc (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4002.0)
   by 0xA6E822D: g_slice_alloc (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4002.0)
   by 0xA6C94F3: g_list_append (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4002.0)
   by 0x44C9AF: search_cb (extcap.c:451)
   by 0x44C6FC: extcap_foreach (extcap.c:204)
   by 0x44CDFF: extcap_get_if_configuration (extcap.c:473)
   by 0x44CE3C: extcap_has_configuration (extcap.c:489)
   by 0x654356: InterfaceTree::display() (interface_tree.cpp:199)
   by 0x6547DF: InterfaceTree::getInterfaceList() (interface_tree.cpp:252)
   by 0xBFCF2A5: QMetaObject::activate(QObject*, int, int, void**) (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.2.1)
   by 0x563F9A: WiresharkApplication::allSystemsGo() (wireshark_application.cpp:914)
   by 0x4478D9: main (wireshark-qt.cpp:1373)

9,126 (432 direct, 8,694 indirect) bytes in 18 blocks are definitely lost in loss record 58,524 of 58,638
   at 0x4C2AB80: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
   by 0xA6D2610: g_malloc (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4002.0)
   by 0xA6E822D: g_slice_alloc (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4002.0)
   by 0xA6C94F3: g_list_append (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4002.0)
   by 0x44C9AF: search_cb (extcap.c:451)
   by 0x44C6FC: extcap_foreach (extcap.c:204)
   by 0x44CDFF: extcap_get_if_configuration (extcap.c:473)
   by 0x44CE3C: extcap_has_configuration (extcap.c:489)
   by 0x654356: InterfaceTree::display() (interface_tree.cpp:199)
   by 0xBFCF2A5: QMetaObject::activate(QObject*, int, int, void**) (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.2.1)
   by 0x4A3214: MainWindow::on_actionCaptureRefreshInterfaces_triggered() (main_window_slots.cpp:3605)
   ...

Change-Id: I9433b8e36813cbef9dca5ab08074e985793f4d0d
Reviewed-on: https://code.wireshark.org/review/13617
Petri-Dish: Alexis La Goutte <alexis.lagoutte@gmail.com>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Roland Knall <rknall@gmail.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/extcap.c b/extcap.c
index a608787dc3..df40bd1017 100644
--- a/extcap.c
+++ b/extcap.c
@@ -417,6 +417,11 @@ extcap_interface_list(char **err_str) {
     return g_list_sort ( ret, if_info_compare );
 }
 
+static void extcap_free_arg_elem(gpointer data, gpointer user_data _U_) {
+    extcap_free_arg((extcap_arg *) data);
+    g_free(data);
+}
+
 static void extcap_free_if_configuration(GList *list)
 {
     GList *elem, *sl;
@@ -426,7 +431,7 @@ static void extcap_free_if_configuration(GList *list)
         if (elem->data != NULL) {
             /* g_list_free_full() only exists since 2.28. */
             sl = g_list_first((GList *)elem->data);
-            g_list_foreach(sl, (GFunc)g_free, NULL);
+            g_list_foreach(sl, (GFunc)extcap_free_arg_elem, NULL);
             g_list_free(sl);
         }
     }
@@ -505,6 +510,7 @@ extcap_has_configuration(const char * ifname, gboolean is_required) {
         }
         walker = walker->next;
     }
+    extcap_free_if_configuration(arguments);
 
     return found;
 }