Re: [dpdk-dev] [dpdk-stable] [PATCH 4/4] net/netvsc: check for overflow on packet info from host

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 10/28/2020 11:08 AM, Luca Boccassi wrote:
> On Tue, 2020-10-27 at 23:07 +0000, Ferruh Yigit wrote:
>> On 10/27/2020 5:10 PM, Luca Boccassi wrote:
>>> On Mon, 2020-08-10 at 19:33 -0700, longli@linuxonhyperv.com wrote:
>>>> From: Stephen Hemminger <stephen@networkplumber.org>
>>>>
>>>> The data from the host is trusted but checked by the driver.
>>>> One check that is missing is that the packet offset and length
>>>> might cause wraparound.
>>>>
>>>> Cc: stable@dpdk.org
>>>>
>>>> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
>>>> Signed-off-by: Long Li <longli@microsoft.com>
>>>> ---
>>>>    drivers/net/netvsc/hn_rxtx.c | 6 ++++--
>>>>    1 file changed, 4 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/net/netvsc/hn_rxtx.c b/drivers/net/netvsc/hn_rxtx.c
>>>> index a388ff258..d8d3f07f5 100644
>>>> --- a/drivers/net/netvsc/hn_rxtx.c
>>>> +++ b/drivers/net/netvsc/hn_rxtx.c
>>>> @@ -666,7 +666,8 @@ static void hn_rndis_rx_data(struct hn_rx_queue *rxq,
>>>>    			     struct hn_rx_bufinfo *rxb,
>>>>    			     void *data, uint32_t dlen)
>>>>    {
>>>> -	unsigned int data_off, data_len, pktinfo_off, pktinfo_len;
>>>> +	unsigned int data_off, data_len, total_len;
>>>> +	unsigned int pktinfo_off, pktinfo_len;
>>>>    	const struct rndis_packet_msg *pkt = data;
>>>>    	struct hn_rxinfo info = {
>>>>    		.vlan_info = HN_NDIS_VLAN_INFO_INVALID,
>>>> @@ -711,7 +712,8 @@ static void hn_rndis_rx_data(struct hn_rx_queue *rxq,
>>>>    			goto error;
>>>>    	}
>>>>    
>>>> -	if (unlikely(data_off + data_len > pkt->len))
>>>> +	if (__builtin_add_overflow(data_off, data_len, &total_len) ||
>>>> +	    total_len > pkt->len)
>>>>    		goto error;
>>>>    
>>>>    	if (unlikely(data_len < RTE_ETHER_HDR_LEN))
>>>
>>> This patch breaks the build with GCC < 5 (CentOS 7, RHEL 7, SLE 12) as
>>> __builtin_add_overflow is not available. Could you please send a follow
>>> up to fix it?
>>>
>>
>> It should be already fixed in the repo:
>> https://git.dpdk.org/dpdk/commit/?id=d73543b5f46d
>>
>> Are you getting the build error with 20.11-rc1?
> 
> No, with the backport. The original patch was marked for stable, but
> the fixup was not.

Yes, it should be also marked for stable, seems missed.

> I'll pick it up.
> 

Thanks.