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

Sergei Shtylyov
2013-05-06T18:38:55Z

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 %?

WBR, Sergei