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[Qemu-devel] [PATCH] qdev: fix use-after-free in the error path of qdev_
From: |
Anthony Liguori |
Subject: |
[Qemu-devel] [PATCH] qdev: fix use-after-free in the error path of qdev_init_nofail |
Date: |
Wed, 27 Jun 2012 07:41:24 -0500 |
>From Markus:
Before:
$ qemu-system-x86_64 -display none -drive if=ide
qemu-system-x86_64: Device needs media, but drive is empty
qemu-system-x86_64: Initialization of device ide-hd failed
[Exit 1 ]
After:
$ qemu-system-x86_64 -display none -drive if=ide
qemu-system-x86_64: Device needs media, but drive is empty
Segmentation fault (core dumped)
[Exit 139 (SIGSEGV)]
This error always existed as qdev_init() frees the object. But QOM
goes a bit further and purposefully sets the class pointer to NULL to
help find use-after-free. It worked :-)
Cc: Andreas Faerber <address@hidden>
Reported-by: Markus Armbruster <address@hidden>
Signed-off-by: Anthony Liguori <address@hidden>
---
hw/qdev.c | 5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/hw/qdev.c b/hw/qdev.c
index a6c4c02..af54467 100644
--- a/hw/qdev.c
+++ b/hw/qdev.c
@@ -258,9 +258,10 @@ int qdev_simple_unplug_cb(DeviceState *dev)
way is somewhat unclean, and best avoided. */
void qdev_init_nofail(DeviceState *dev)
{
+ const char *typename = object_get_typename(OBJECT(dev));
+
if (qdev_init(dev) < 0) {
- error_report("Initialization of device %s failed",
- object_get_typename(OBJECT(dev)));
+ error_report("Initialization of device %s failed", typename);
exit(1);
}
}
--
1.7.5.4
- [Qemu-devel] [PATCH] qdev: fix use-after-free in the error path of qdev_init_nofail,
Anthony Liguori <=