tipc: potential divide by zero in tipc_link_recv_fragment()

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>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/tipc/link.c b/net/tipc/link.c
index 3a6064b3d6668f202e61181f74eb4115590fbfd0..a80feee5197a1c8a79a9397091ff9d0d72b09c22 100644 (file)
--- 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);
                pbuf = tipc_buf_acquire(msg_size(imsg));
                if (pbuf != NULL) {
                        pbuf->next = *pending;