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Re: [Qemu-devel] [PATCH] usb-mtp: Assert on suspicious TYPE_DATA packet
From: |
Bandan Das |
Subject: |
Re: [Qemu-devel] [PATCH] usb-mtp: Assert on suspicious TYPE_DATA packet from initiator |
Date: |
Fri, 18 May 2018 15:04:51 -0400 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/25.3 (gnu/linux) |
Peter Maydell <address@hidden> writes:
> On 18 May 2018 at 19:38, Bandan Das <address@hidden> wrote:
>> Peter Maydell <address@hidden> writes:
>>
>>> On 18 May 2018 at 19:22, Bandan Das <address@hidden> wrote:
>>>>
>>>> CID 1390604
>>>> If the initiator sends a packet with TYPE_DATA set without
>>>> initiating a CMD_GET_OBJECT_INFO first, then usb_mtp_get_data
>>>> can trip on a null s->data_out.
>>>>
>>>> Signed-off-by: Bandan Das <address@hidden>
>>>
>>> I think you said this can be provoked by the guest?
>>
>> Yes, this can only be initated by the guest as far as I
>> understand.
>>
>>> Misbehaving or malicious guests should never be able
>>> to provoke assertions.
>>
>> I am not sure, I thought it's better to kill a misbehaving guest rather
>> than silently letting it run. Anyway, it's possible to send a
>> No_Valid_ObjectInfo as well and we wouldn't have to mark it as a
>> false positive either.
>
> Broadly speaking, where we're emulating hardware we should do
> what the hardware does when the guest does wrong things to it.
> A real server doesn't suddenly vanish leaving behind a
> message saying "assertion failed" :-)
Posted v2 and agree with you! Especially, since the protocol does specify
the case where something like this can happen.
Thanks for reviewing,
Bandan
> thanks
> -- PMM
- [Qemu-devel] [PULL 0/3] Usb 20180507 patches, Gerd Hoffmann, 2018/05/07
- [Qemu-devel] [PULL 1/3] usb-mtp: Add some NULL checks for issues pointed out by coverity, Gerd Hoffmann, 2018/05/07
- Re: [Qemu-devel] [PULL 1/3] usb-mtp: Add some NULL checks for issues pointed out by coverity, Peter Maydell, 2018/05/15
- Re: [Qemu-devel] [PULL 1/3] usb-mtp: Add some NULL checks for issues pointed out by coverity, Bandan Das, 2018/05/17
- [Qemu-devel] [PATCH] usb-mtp: Assert on suspicious TYPE_DATA packet from initiator, Bandan Das, 2018/05/18
- Re: [Qemu-devel] [PATCH] usb-mtp: Assert on suspicious TYPE_DATA packet from initiator, Peter Maydell, 2018/05/18
- Re: [Qemu-devel] [PATCH] usb-mtp: Assert on suspicious TYPE_DATA packet from initiator, Bandan Das, 2018/05/18
- Re: [Qemu-devel] [PATCH] usb-mtp: Assert on suspicious TYPE_DATA packet from initiator, Peter Maydell, 2018/05/18
- Re: [Qemu-devel] [PATCH] usb-mtp: Assert on suspicious TYPE_DATA packet from initiator,
Bandan Das <=
- [Qemu-devel] [PATCH v2] usb-mtp: Return error on suspicious TYPE_DATA packet from initiator, Bandan Das, 2018/05/18
- Re: [Qemu-devel] [PULL 1/3] usb-mtp: Add some NULL checks for issues pointed out by coverity, Bandan Das, 2018/05/18
[Qemu-devel] [PULL 2/3] usb-mtp: Unconditionally check for the readonly bit, Gerd Hoffmann, 2018/05/07
[Qemu-devel] [PULL 3/3] usb-host: skip open on pending postload bh, Gerd Hoffmann, 2018/05/07
Re: [Qemu-devel] [PULL 0/3] Usb 20180507 patches, Peter Maydell, 2018/05/08