[PATCH v2] virnetdevtap: Fix memory leak in virNetDevTapReattachBridge

[liu.song13]

From: QiangWei Zhang <zhang.qiang...@zte.com.cn>

Variable &apos;master&apos; needs to be free because it will be reassigned in
virNetDevOpenvswitchInterfaceGetMaster().

The leaked stack:
Direct leak of 11 byte(s) in 1 object(s) allocated from:
#0 0x7f7dad8ba6df in __interceptor_malloc (/lib64/libasan.so.8+0xba6df)
#1 0x7f7dad715728 in g_malloc (/lib64/libglib-2.0.so.0+0x60728)
#2 0x7f7dad72d8b2 in g_strdup (/lib64/libglib-2.0.so.0+0x788b2)
#3 0x7f7dacb63088 in g_strdup_inline /usr/include/glib-2.0/glib/gstrfuncs.h:321
#4 0x7f7dacb63088 in virNetDevGetName ../src/util/virnetdev.c:823
#5 0x7f7dacb63886 in virNetDevGetMaster ../src/util/virnetdev.c:909
#6 0x7f7dacb90288 in virNetDevTapReattachBridge ../src/util/virnetdevtap.c:527
#7 0x7f7dacd5cd67 in virDomainNetNotifyActualDevice 
../src/conf/domain_conf.c:30505
#8 0x7f7da3a10bc3 in qemuProcessNotifyNets ../src/qemu/qemu_process.c:3290
#9 0x7f7da3a375c6 in qemuProcessReconnect ../src/qemu/qemu_process.c:9211
#10 0x7f7dacc0cc53 in virThreadHelper ../src/util/virthread.c:256
#11 0x7f7dac2875d4 in start_thread (/lib64/libc.so.6+0x875d4)
#12 0x7f7dac3091bb in __GI___clone3 (/lib64/libc.so.6+0x1091bb)

Fixes: de938b92c9d3a47647164aa643c20d2fc96cd2bc
Signed-off-by: QiangWei Zhang <zhang.qiang...@zte.com.cn>
Reviewed-by: Peter Krempa <pkre...@redhat.com>
---
src/util/virnetdevtap.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/src/util/virnetdevtap.c b/src/util/virnetdevtap.c
index 1dc77f0f5c..f26afb2ce0 100644
--- a/src/util/virnetdevtap.c
+++ b/src/util/virnetdevtap.c
@@ -541,6 +541,9 @@ virNetDevTapReattachBridge(const char *tapname,
/* IFLA_MASTER for a tap on an OVS switch is always "ovs-system" */
if (STREQ_NULLABLE(master, "ovs-system")) {
useOVS = true;
+
+        /* master needs to be released here because it will be reassigned */
+        g_clear_pointer(&master, g_free);
if (virNetDevOpenvswitchInterfaceGetMaster(tapname, &master) < 0)
return -1;
}
--
2.27.0