Re: [dpdk-dev] [PATCH] vhost: fix possible null pointer dereferencing

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 11/27/18 10:44 AM, Tiwei Bie wrote:
> On Tue, Nov 27, 2018 at 10:23:25AM +0100, Maxime Coquelin wrote:
>> If mmap() call fails in vhost_user_set_mem_table, dev->mem
>> is set to NULL. If later, qva_to_vva() is called, a segfault
>> occurs.
>>
>> Fixes: 8f972312b8f4 ("vhost: support vhost-user")
>> Cc: stable@dpdk.org
>>
>> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
>> ---
>>   lib/librte_vhost/vhost_user.c | 3 +++
>>   1 file changed, 3 insertions(+)
>>
>> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
>> index 3ea64eba6..c44fef9cc 100644
>> --- a/lib/librte_vhost/vhost_user.c
>> +++ b/lib/librte_vhost/vhost_user.c
>> @@ -489,6 +489,9 @@ qva_to_vva(struct virtio_net *dev, uint64_t qva, uint64_t *len)
>>   	struct rte_vhost_mem_region *r;
>>   	uint32_t i;
>>   
>> +	if (unlikely(!dev || !dev->mem))
>> +		return 0;
> 
> Better to also zero *len.
> 
> Reviewed-by: Tiwei Bie <tiwei.bie@intel.com>

Right, I'll post a v2 zeroing *len.

Thanks,
Maxime

> 
>> +
>>   	/* Find the region where the address lives. */
>>   	for (i = 0; i < dev->mem->nregions; i++) {
>>   		r = &dev->mem->regions[i];
>> -- 
>> 2.17.2
>>