[Qemu-devel] [PATCH 04/24] Correctly free nd structure

[Mark McLoughlin <markmc@redhat.com>]

From: Glauber Costa <glommer@redhat.com>

When we "free" a NICInfo structure, we can leak pointers, since we don't do
much more than setting used = 0.

We free() the model parameter, but we don't set it to NULL. This means that
a new user of this structure will see garbage in there. It was not noticed
before because reusing a NICInfo is not that common, but it can be, for
users of device pci hotplug.

A user hit it, described at https://bugzilla.redhat.com/524022

This patch memset's the whole structure, guaranteeing that anyone reusing it
will see a fresh NICinfo. Also, we free some other strings that are currently
leaking.

This codebase is quite old, so this patch should feed all stable trees.

Signed-off-by: Glauber Costa <glommer@redhat.com>
Signed-off-by: Mark McLoughlin <markmc@redhat.com>
---
 net.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/net.c b/net.c
index d04b6bd..422ef4c 100644
--- a/net.c
+++ b/net.c
@@ -2434,6 +2434,7 @@ int net_client_init(Monitor *mon, const char *device, const char *p)
             goto out;
         }
         nd = &nd_table[idx];
+        memset(nd, 0, sizeof(*nd));
         macaddr = nd->macaddr;
         macaddr[0] = 0x52;
         macaddr[1] = 0x54;
@@ -2803,8 +2804,13 @@ void net_client_uninit(NICInfo *nd)
 {
     nd->vlan->nb_guest_devs--;
     nb_nics--;
-    nd->used = 0;
+
     qemu_free(nd->model);
+    qemu_free(nd->name);
+    qemu_free(nd->devaddr);
+    qemu_free(nd->id);
+
+    nd->used = 0;
 }
 
 static int net_host_check_device(const char *device)
-- 
1.6.2.5