[Bridge] [PATCH] net: bridge: fix potential NULL pointer dereference

[Gustavo A. R. Silva]

Hi Nikolay,

Quoting Nikolay Aleksandrov <nikolay at cumulusnetworks.com>:

> On 06/06/17 00:30, Gustavo A. R. Silva wrote:
>> Add NULL check before dereferencing pointer _p_ inside br_afspec().
>>
>> Addresses-Coverity-ID: 1401872
>> Signed-off-by: Gustavo A. R. Silva <garsilva at embeddedor.com>
>> ---
>>  net/bridge/br_netlink.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
>> index 1e63ec4..ad85a9c 100644
>> --- a/net/bridge/br_netlink.c
>> +++ b/net/bridge/br_netlink.c
>> @@ -776,7 +776,7 @@ int br_setlink(struct net_device *dev, struct  
>> nlmsghdr *nlh, u16 flags)
>>  			goto out;
>>  	}
>>
>> -	if (afspec) {
>> +	if (p && afspec) {
>>  		err = br_afspec((struct net_bridge *)netdev_priv(dev), p,
>>  				afspec, RTM_SETLINK);
>>  	}
>>
>
> While I see a possible issue with the new bridge tunnel code (+CC  
> Roopa), this is
> the wrong fix because there are legitimate use cases where p is null  
> and br_afspec
> is called.
> We need to change the p->flags check in br_afspec()'s  
> IFLA_BRIDGE_VLAN_TUNNEL_INFO case
> to check for a NULL p first.
>

You're right. I got it.

> Thanks for the report!

Sure thing, glad to help.

Thank you!
--
Gustavo A. R. Silva