Hi,

On Wed, 21 Nov 2018, Qian Cai wrote:

> To make overflows as obvious as possible and to prevent code from blithely
> proceeding with a truncated string. This also has a side-effect to fix a
> compilation warning using GCC 8.2.1.
> 
> net/netfilter/ipset/ip_set_core.c: In function 'ip_set_sockfn_get':
> net/netfilter/ipset/ip_set_core.c:2027:3: warning: 'strncpy' writing 32
> bytes into a region of size 2 overflows the destination
> [-Wstringop-overflow=]

But without checking the return value of strscpy(), I don't see why it's 
better to call strscpy(). Also, with your patch I get the warning:

  CC [M]  /usr/src/git/ipset/ipset/kernel/net/netfilter/xt_set.o
  CC [M]  
/usr/src/git/ipset/ipset/kernel/net/netfilter/ipset/ip_set_core.o
/usr/src/git/ipset/ipset/kernel/net/netfilter/ipset/ip_set_core.c: In 
function 'ip_set_sockfn_get':
/usr/src/git/ipset/ipset/kernel/net/netfilter/ipset/ip_set_core.c:2184:3: 
warning: ignoring return value of 'strscpy', declared with attribute 
warn_unused_result [-Wunused-result]
   strscpy(req_get->set.name, set ? set->name : "",
   ^

So please add the proper checking of the return value.

Best regards,
Jozsef
> Signed-off-by: Qian Cai <c...@gmx.us>
> ---
>  net/netfilter/ipset/ip_set_core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/netfilter/ipset/ip_set_core.c 
> b/net/netfilter/ipset/ip_set_core.c
> index 1577f2f..915aa0d 100644
> --- a/net/netfilter/ipset/ip_set_core.c
> +++ b/net/netfilter/ipset/ip_set_core.c
> @@ -2024,7 +2024,7 @@ static int ip_set_protocol(struct net *net, struct sock 
> *ctnl,
>               }
>               nfnl_lock(NFNL_SUBSYS_IPSET);
>               set = ip_set(inst, req_get->set.index);
> -             strncpy(req_get->set.name, set ? set->name : "",
> +             strscpy(req_get->set.name, set ? set->name : "",
>                       IPSET_MAXNAMELEN);
>               nfnl_unlock(NFNL_SUBSYS_IPSET);
>               goto copy;
> -- 
> 1.8.3.1
> 
> 

-
E-mail  : kad...@blackhole.kfki.hu, kadlecsik.joz...@wigner.mta.hu
PGP key : http://www.kfki.hu/~kadlec/pgp_public_key.txt
Address : Wigner Research Centre for Physics, Hungarian Academy of Sciences
          H-1525 Budapest 114, POB. 49, Hungary

Reply via email to