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

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

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?