Re: [Qemu-devel] [PATCH v2] virtio: add check for descriptor's mapped address

2016-09-19 Thread P J P 
+-- On Mon, 19 Sep 2016, Laszlo Ersek wrote --+
| Prasad, can you please send a v3 then, to address Stefan's feedback?

Yes, sent patch v3. Thank you.
--
Prasad J Pandit / Red Hat Product Security Team
47AF CE69 3A90 54AA 9045 1053 DD13 3D32 FE5B 041F

Re: [Qemu-devel] [PATCH v2] virtio: add check for descriptor's mapped address

2016-09-19 Thread Laurent Vivier 


On 19/09/2016 18:59, Laszlo Ersek wrote:
> On 09/19/16 17:55, Stefan Hajnoczi wrote:
>> On Mon, Sep 19, 2016 at 02:36:11PM +0530, P J P wrote:
>>> From: Prasad J Pandit 
>>>
>>> virtio back end uses set of buffers to facilitate I/O operations.
>>> If its size is too large, 'cpu_physical_memory_map' could return
>>> a null address. This would result in a null dereference while
>>> un-mapping descriptors. Add check to avoid it.
>>>
>>> Reported-by: Qinghao Tang 
>>> Signed-off-by: Prasad J Pandit 
>>> ---
>>>  hw/virtio/virtio.c | 5 +
>>>  1 file changed, 5 insertions(+)
>>>
>>> Update per:
>>>   -> https://lists.gnu.org/archive/html/qemu-devel/2016-09/msg03889.html
>>>
>>> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
>>> index 15ee3a7..311dd0b 100644
>>> --- a/hw/virtio/virtio.c
>>> +++ b/hw/virtio/virtio.c
>>> @@ -472,6 +472,11 @@ static void virtqueue_map_desc(unsigned int *p_num_sg, 
>>> hwaddr *addr, struct iove
>>>  }
>>>  
>>>  iov[num_sg].iov_base = cpu_physical_memory_map(pa, &len, is_write);
>>> +if (!iov[num_sg].iov_base) {
>>> +error_report("virtio: bogus descriptor or out of resources");
>>> +exit(EXIT_FAILURE);
>>
>> exit(1) is used everywhere else in the file (including just a few lines
>> above in the same function).  Please use exit(1) for consistency.
> 
> Laurent's pending series
> 
> [Qemu-devel] [PATCH 00/26] trivial: use exit(EXIT_SUCCESS) and
>exit(EXIT_FAILURE)
> 
> specifically his patch
> 
> [Qemu-devel] [PATCH 11/26] pci, virtio: use exit(EXIT_SUCCESS) and
>exit(EXIT_FAILURE)
> 
> converts the argument of the exit() that you name to EXIT_FAILURE.
> 
> So using EXIT_FAILURE in Prasad's patch is actually what will uphold
> consistency.
> 
>> Looks fine otherwise.
>>

Laszlo, it seems Peter (and some others) would prefer to use exit(1)
instead of exit(EXIT_FAILURE), so I don't think my series will be applied.

Laurent

Re: [Qemu-devel] [PATCH v2] virtio: add check for descriptor's mapped address

2016-09-19 Thread Laszlo Ersek 
On 09/19/16 19:16, Laurent Vivier wrote:
> 
> 
> On 19/09/2016 18:59, Laszlo Ersek wrote:
>> On 09/19/16 17:55, Stefan Hajnoczi wrote:
>>> On Mon, Sep 19, 2016 at 02:36:11PM +0530, P J P wrote:
 From: Prasad J Pandit 

 virtio back end uses set of buffers to facilitate I/O operations.
 If its size is too large, 'cpu_physical_memory_map' could return
 a null address. This would result in a null dereference while
 un-mapping descriptors. Add check to avoid it.

 Reported-by: Qinghao Tang 
 Signed-off-by: Prasad J Pandit 
 ---
  hw/virtio/virtio.c | 5 +
  1 file changed, 5 insertions(+)

 Update per:
   -> https://lists.gnu.org/archive/html/qemu-devel/2016-09/msg03889.html

 diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
 index 15ee3a7..311dd0b 100644
 --- a/hw/virtio/virtio.c
 +++ b/hw/virtio/virtio.c
 @@ -472,6 +472,11 @@ static void virtqueue_map_desc(unsigned int 
 *p_num_sg, hwaddr *addr, struct iove
  }
  
  iov[num_sg].iov_base = cpu_physical_memory_map(pa, &len, 
 is_write);
 +if (!iov[num_sg].iov_base) {
 +error_report("virtio: bogus descriptor or out of resources");
 +exit(EXIT_FAILURE);
>>>
>>> exit(1) is used everywhere else in the file (including just a few lines
>>> above in the same function).  Please use exit(1) for consistency.
>>
>> Laurent's pending series
>>
>> [Qemu-devel] [PATCH 00/26] trivial: use exit(EXIT_SUCCESS) and
>>exit(EXIT_FAILURE)
>>
>> specifically his patch
>>
>> [Qemu-devel] [PATCH 11/26] pci, virtio: use exit(EXIT_SUCCESS) and
>>exit(EXIT_FAILURE)
>>
>> converts the argument of the exit() that you name to EXIT_FAILURE.
>>
>> So using EXIT_FAILURE in Prasad's patch is actually what will uphold
>> consistency.
>>
>>> Looks fine otherwise.
>>>
> 
> Laszlo, it seems Peter (and some others) would prefer to use exit(1)
> instead of exit(EXIT_FAILURE), so I don't think my series will be applied.

Thanks for the information, Laurent!

Prasad, can you please send a v3 then, to address Stefan's feedback?

Thank you
Laszlo

Re: [Qemu-devel] [PATCH v2] virtio: add check for descriptor's mapped address

2016-09-19 Thread Laszlo Ersek 
On 09/19/16 17:55, Stefan Hajnoczi wrote:
> On Mon, Sep 19, 2016 at 02:36:11PM +0530, P J P wrote:
>> From: Prasad J Pandit 
>>
>> virtio back end uses set of buffers to facilitate I/O operations.
>> If its size is too large, 'cpu_physical_memory_map' could return
>> a null address. This would result in a null dereference while
>> un-mapping descriptors. Add check to avoid it.
>>
>> Reported-by: Qinghao Tang 
>> Signed-off-by: Prasad J Pandit 
>> ---
>>  hw/virtio/virtio.c | 5 +
>>  1 file changed, 5 insertions(+)
>>
>> Update per:
>>   -> https://lists.gnu.org/archive/html/qemu-devel/2016-09/msg03889.html
>>
>> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
>> index 15ee3a7..311dd0b 100644
>> --- a/hw/virtio/virtio.c
>> +++ b/hw/virtio/virtio.c
>> @@ -472,6 +472,11 @@ static void virtqueue_map_desc(unsigned int *p_num_sg, 
>> hwaddr *addr, struct iove
>>  }
>>  
>>  iov[num_sg].iov_base = cpu_physical_memory_map(pa, &len, is_write);
>> +if (!iov[num_sg].iov_base) {
>> +error_report("virtio: bogus descriptor or out of resources");
>> +exit(EXIT_FAILURE);
> 
> exit(1) is used everywhere else in the file (including just a few lines
> above in the same function).  Please use exit(1) for consistency.

Laurent's pending series

[Qemu-devel] [PATCH 00/26] trivial: use exit(EXIT_SUCCESS) and
   exit(EXIT_FAILURE)

specifically his patch

[Qemu-devel] [PATCH 11/26] pci, virtio: use exit(EXIT_SUCCESS) and
   exit(EXIT_FAILURE)

converts the argument of the exit() that you name to EXIT_FAILURE.

So using EXIT_FAILURE in Prasad's patch is actually what will uphold
consistency.

> Looks fine otherwise.
> 

Thanks!
Laszlo

Re: [Qemu-devel] [PATCH v2] virtio: add check for descriptor's mapped address

2016-09-19 Thread Stefan Hajnoczi 
On Mon, Sep 19, 2016 at 02:36:11PM +0530, P J P wrote:
> From: Prasad J Pandit 
> 
> virtio back end uses set of buffers to facilitate I/O operations.
> If its size is too large, 'cpu_physical_memory_map' could return
> a null address. This would result in a null dereference while
> un-mapping descriptors. Add check to avoid it.
> 
> Reported-by: Qinghao Tang 
> Signed-off-by: Prasad J Pandit 
> ---
>  hw/virtio/virtio.c | 5 +
>  1 file changed, 5 insertions(+)
> 
> Update per:
>   -> https://lists.gnu.org/archive/html/qemu-devel/2016-09/msg03889.html
> 
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index 15ee3a7..311dd0b 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -472,6 +472,11 @@ static void virtqueue_map_desc(unsigned int *p_num_sg, 
> hwaddr *addr, struct iove
>  }
>  
>  iov[num_sg].iov_base = cpu_physical_memory_map(pa, &len, is_write);
> +if (!iov[num_sg].iov_base) {
> +error_report("virtio: bogus descriptor or out of resources");
> +exit(EXIT_FAILURE);

exit(1) is used everywhere else in the file (including just a few lines
above in the same function).  Please use exit(1) for consistency.

Looks fine otherwise.


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Re: [Qemu-devel] [PATCH v2] virtio: add check for descriptor's mapped address

2016-09-19 Thread Laszlo Ersek 
On 09/19/16 11:06, P J P wrote:
> From: Prasad J Pandit 
> 
> virtio back end uses set of buffers to facilitate I/O operations.
> If its size is too large, 'cpu_physical_memory_map' could return
> a null address. This would result in a null dereference while
> un-mapping descriptors. Add check to avoid it.
> 
> Reported-by: Qinghao Tang 
> Signed-off-by: Prasad J Pandit 
> ---
>  hw/virtio/virtio.c | 5 +
>  1 file changed, 5 insertions(+)
> 
> Update per:
>   -> https://lists.gnu.org/archive/html/qemu-devel/2016-09/msg03889.html
> 
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index 15ee3a7..311dd0b 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -472,6 +472,11 @@ static void virtqueue_map_desc(unsigned int *p_num_sg, 
> hwaddr *addr, struct iove
>  }
>  
>  iov[num_sg].iov_base = cpu_physical_memory_map(pa, &len, is_write);
> +if (!iov[num_sg].iov_base) {
> +error_report("virtio: bogus descriptor or out of resources");
> +exit(EXIT_FAILURE);
> +}
> +
>  iov[num_sg].iov_len = len;
>  addr[num_sg] = pa;
>  
> 

Reviewed-by: Laszlo Ersek

[Qemu-devel] [PATCH v2] virtio: add check for descriptor's mapped address

2016-09-19 Thread P J P 
From: Prasad J Pandit 

virtio back end uses set of buffers to facilitate I/O operations.
If its size is too large, 'cpu_physical_memory_map' could return
a null address. This would result in a null dereference while
un-mapping descriptors. Add check to avoid it.

Reported-by: Qinghao Tang 
Signed-off-by: Prasad J Pandit 
---
 hw/virtio/virtio.c | 5 +
 1 file changed, 5 insertions(+)

Update per:
  -> https://lists.gnu.org/archive/html/qemu-devel/2016-09/msg03889.html

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 15ee3a7..311dd0b 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -472,6 +472,11 @@ static void virtqueue_map_desc(unsigned int *p_num_sg, 
hwaddr *addr, struct iove
 }
 
 iov[num_sg].iov_base = cpu_physical_memory_map(pa, &len, is_write);
+if (!iov[num_sg].iov_base) {
+error_report("virtio: bogus descriptor or out of resources");
+exit(EXIT_FAILURE);
+}
+
 iov[num_sg].iov_len = len;
 addr[num_sg] = pa;
 
-- 
2.5.5