[Qemu-devel] [PULL 5/6] hw/pci: use-after-free in pci_nic_init_nofail when nic device fails to initialize

[Jason Wang]

From: Alex Kompel <address@hidden>

object_property_set_bool(OBJECT(dev), true, "realized", &err) in
pci_nic_init_nofail may release the object if device fails to
initialize which leads to use-after-free in error handling block.
qdev_init_nofail does the same thing while holding the reference.

(gdb) run -net nic
qemu-system-x86_64: failed to find romfile "efi-e1000.rom"

Program received signal SIGSEGV, Segmentation fault.
object_unparent (obj=0x7fffe96a0010) at qom/object.c:440
440     in qom/object.c
(gdb) bt
<nd_table>, rootbus=0x5555567ed990, default_model=<optimized out>,
default_devaddr=<optimized out>) at hw/pci/pci.c:1812
pci_bus=0x5555567ed990) at hw/i386/pc.c:1634
pci_type=0x555555c1a523 "i440FX", host_type=0x555555ba564e
"i440FX-pcihost") at hw/i386/pc_piix.c:241
out>, envp=<optimized out>) at vl.c:4481

Signed-off-by: Alex Kompel <address@hidden>
Signed-off-by: Jason Wang <address@hidden>
---
 hw/pci/pci.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 637d545..fe9acec 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -1779,7 +1779,6 @@ PCIDevice *pci_nic_init_nofail(NICInfo *nd, PCIBus 
*rootbus,
                                const char *default_devaddr)
 {
     const char *devaddr = nd->devaddr ? nd->devaddr : default_devaddr;
-    Error *err = NULL;
     PCIBus *bus;
     PCIDevice *pci_dev;
     DeviceState *dev;
@@ -1805,13 +1804,7 @@ PCIDevice *pci_nic_init_nofail(NICInfo *nd, PCIBus 
*rootbus,
     pci_dev = pci_create(bus, devfn, pci_nic_names[i]);
     dev = &pci_dev->qdev;
     qdev_set_nic_properties(dev, nd);
-
-    object_property_set_bool(OBJECT(dev), true, "realized", &err);
-    if (err) {
-        error_report_err(err);
-        object_unparent(OBJECT(dev));
-        exit(1);
-    }
+    qdev_init_nofail(dev);
 
     return pci_dev;
 }
-- 
2.7.4