Re: [patch 2/2] tipc: potential divide by zero in tipc_link_recv_fragment()

Dan Carpenter
2013-05-06T18:50:03Z

On Mon, May 06, 2013 at 10:38:53PM +0400, Sergei Shtylyov wrote:
> Hello.
>
> On 06-05-2013 22:29, Dan Carpenter wrote:
>
> >The worry here is that fragm_sz could be zero since it comes from
> >skb->data.
>
> >Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>
> >diff --git a/net/tipc/link.c b/net/tipc/link.c
> >index 3a6064b3..de94493 100644
> >--- a/net/tipc/link.c
> >+++ b/net/tipc/link.c
> >@@ -2524,14 +2524,16 @@ int tipc_link_recv_fragment(struct sk_buff **pending, struct sk_buff **fb,
> > struct tipc_msg *imsg = (struct tipc_msg *)msg_data(fragm);
> > u32 msg_sz = msg_size(imsg);
> > u32 fragm_sz = msg_data_sz(fragm);
> >- u32 exp_fragm_cnt = msg_sz/fragm_sz + !!(msg_sz % fragm_sz);
> >+ u32 exp_fragm_cnt;
> > u32 max = TIPC_MAX_USER_MSG_SIZE + NAMED_H_SIZE;
> >+
> > if (msg_type(imsg) == TIPC_MCAST_MSG)
> > max = TIPC_MAX_USER_MSG_SIZE + MCAST_H_SIZE;
> >- if (msg_size(imsg) > max) {
> >+ if (fragm_sz == 0 || msg_size(imsg) > max) {
> > kfree_skb(fbuf);
> > return 0;
> > }
> >+ exp_fragm_cnt = msg_sz/fragm_sz + !!(msg_sz % fragm_sz);
>
> Don't you think spaces around / should be added at least for
> consistency with %?

Yep. I missed that. I'll resend.

regards,
dan carpenter