Re: [PATCH-for-6.2] net: vmxnet3: validate configuration values during activate (CVE-2021-20203)

[Philippe Mathieu-Daudé]

ping?

On 10/18/21 11:09, P J P wrote:
> On Monday, 18 October, 2021, 12:20:55 pm IST, Thomas Huth <thuth@redhat.com> 
> wrote:
> On 30/01/2021 14.16, P J P wrote:
>>> diff --git a/hw/net/vmxnet3.c b/hw/net/vmxnet3.c
>>> index eff299f629..4a910ca971 100644
>>> --- a/hw/net/vmxnet3.c
>>> +++ b/hw/net/vmxnet3.c
>>> @@ -1420,6 +1420,7 @@ static void vmxnet3_activate_device(VMXNET3State *s)
>>>       vmxnet3_setup_rx_filtering(s);
>>>       /* Cache fields from shared memory */
>>>       s->mtu = VMXNET3_READ_DRV_SHARED32(d, s->drv_shmem, devRead.misc.mtu);
>>> +    assert(VMXNET3_MIN_MTU <= s->mtu && s->mtu < VMXNET3_MAX_MTU);
>>>       VMW_CFPRN("MTU is %u", s->mtu);
>>>   
>>>       s->max_rx_frags =
>>> @@ -1473,6 +1474,9 @@ static void vmxnet3_activate_device(VMXNET3State *s)
>>>           /* Read rings memory locations for TX queues */
>>>           pa = VMXNET3_READ_TX_QUEUE_DESCR64(d, qdescr_pa, 
>>> conf.txRingBasePA);
>>>           size = VMXNET3_READ_TX_QUEUE_DESCR32(d, qdescr_pa, 
>>> conf.txRingSize);
>>> +        if (size > VMXNET3_TX_RING_MAX_SIZE) {
>>> +            size = VMXNET3_TX_RING_MAX_SIZE;
>>> +        }
>>>   
>>>           vmxnet3_ring_init(d, &s->txq_descr[i].tx_ring, pa, size,
>>>                             sizeof(struct Vmxnet3_TxDesc), false);
>>> @@ -1483,6 +1487,9 @@ static void vmxnet3_activate_device(VMXNET3State *s)
>>>           /* TXC ring */
>>>           pa = VMXNET3_READ_TX_QUEUE_DESCR64(d, qdescr_pa, 
>>> conf.compRingBasePA);
>>>           size = VMXNET3_READ_TX_QUEUE_DESCR32(d, qdescr_pa, 
>>> conf.compRingSize);
>>> +        if (size > VMXNET3_TC_RING_MAX_SIZE) {
>>> +            size = VMXNET3_TC_RING_MAX_SIZE;
>>> +        }
>>>           vmxnet3_ring_init(d, &s->txq_descr[i].comp_ring, pa, size,
>>>                             sizeof(struct Vmxnet3_TxCompDesc), true);
>>>           VMXNET3_RING_DUMP(VMW_CFPRN, "TXC", i, 
>>> &s->txq_descr[i].comp_ring);
>>> @@ -1524,6 +1531,9 @@ static void vmxnet3_activate_device(VMXNET3State *s)
>>>               /* RX rings */
>>>               pa = VMXNET3_READ_RX_QUEUE_DESCR64(d, qd_pa, 
>>> conf.rxRingBasePA[j]);
>>>               size = VMXNET3_READ_RX_QUEUE_DESCR32(d, qd_pa, 
>>> conf.rxRingSize[j]);
>>> +            if (size > VMXNET3_RX_RING_MAX_SIZE) {
>>> +                size = VMXNET3_RX_RING_MAX_SIZE;
>>> +            }
>>>               vmxnet3_ring_init(d, &s->rxq_descr[i].rx_ring[j], pa, size,
>>>                                 sizeof(struct Vmxnet3_RxDesc), false);
>>>               VMW_CFPRN("RX queue %d:%d: Base: %" PRIx64 ", Size: %d",
>>> @@ -1533,6 +1543,9 @@ static void vmxnet3_activate_device(VMXNET3State *s)
>>>           /* RXC ring */
>>>           pa = VMXNET3_READ_RX_QUEUE_DESCR64(d, qd_pa, conf.compRingBasePA);
>>>           size = VMXNET3_READ_RX_QUEUE_DESCR32(d, qd_pa, conf.compRingSize);
>>> +        if (size > VMXNET3_RC_RING_MAX_SIZE) {
>>> +            size = VMXNET3_RC_RING_MAX_SIZE;
>>> +        }
>>>           vmxnet3_ring_init(d, &s->rxq_descr[i].comp_ring, pa, size,
>>>                             sizeof(struct Vmxnet3_RxCompDesc), true);
>>>           VMW_CFPRN("RXC queue %d: Base: %" PRIx64 ", Size: %d", i, pa, 
>>> size);
>>>
>>>
>> Ping!
>>
>> According to 
>> https://gitlab.com/qemu-project/qemu/-/issues/308#note_705736713 this is 
>> still an issue...
>>
>> Patch looks fine to me ... maybe just add some 
>> qemu_log_mask(LOG_GUEST_ERROR, ...) statements before correcting the values?
> 
> 
> * Oops! Not sure how I missed it, thought it was pulled upstream.
>   Will send a revised patch.
> 
> 
> Thank you.
> ---
>   - P J P
>