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

[Jason Wang <jasowang@redhat.com>]

On 2017年01月09日 13:26, Alex Kompel wrote:
> Looks like this line got wrapped: "@@ -1805,13 +1805,7 @@ PCIDevice
> *pci_nic_init_nofail(NICInfo *nd, PCIBus *rootbus,"
> Sorry about that. Could you unwrap it or use the attached text file?
>
> Thanks,
> -Alex

Ok, applied. But please use git format-patch and git send-email for 
future submission of patches.

Thanks

>
> On Sun, Jan 8, 2017 at 8:06 PM, Jason Wang <jasowang@redhat.com> wrote:
>>
>> On 2017年01月07日 07:48, Alex Kompel wrote:
>>> 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
>>> #0  object_unparent (obj=0x7fffe96a0010) at qom/object.c:440
>>> #1  0x000055555598c30d in pci_nic_init_nofail (nd=0x55555616b460
>>> <nd_table>, rootbus=0x5555567ed990, default_model=<optimized out>,
>>> default_devaddr=<optimized out>) at hw/pci/pci.c:1812
>>> #2  0x00005555557ff52c in pc_nic_init (isa_bus=0x55555733c610,
>>> pci_bus=0x5555567ed990) at hw/i386/pc.c:1634
>>> #3  0x00005555558021ad in pc_init1 (machine=0x55555661ee10,
>>> pci_type=0x555555c1a523 "i440FX", host_type=0x555555ba564e
>>> "i440FX-pcihost") at hw/i386/pc_piix.c:241
>>> #4  0x00005555557519cb in main (argc=<optimized out>, argv=<optimized
>>> out>, envp=<optimized out>) at vl.c:4481
>>>
>>> Signed-off-by: Alex Kompel <barbos@gmail.com>
>>> ---
>>>    hw/pci/pci.c | 8 +-------
>>>    1 file changed, 1 insertion(+), 7 deletions(-)
>>>
>>> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
>>> index 24fae16..2fd1b9e 100644
>>> --- a/hw/pci/pci.c
>>> +++ b/hw/pci/pci.c
>>> @@ -1805,13 +1805,7 @@ PCIDevice *pci_nic_init_nofail(NICInfo *nd,
>>> PCIBus *rootbus,
>>
>> Hello, looks like the patch were corrupted possibly by your email client.
>> Please check, we usually send patch through git send-email.
>>
>> Thanks
>>
>>
>>>        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;
>>>    }
>>> --
>>> 2.8.3
>>>