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>

1 files changed, 4 insertions, 2 deletions

diff --git a/net/tipc/link.c b/net/tipc/link.c
index 3a6064b3d666..a80feee5197a 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);
                 pbuf = tipc_buf_acquire(msg_size(imsg));
                 if (pbuf != NULL) {
                         pbuf->next = *pending;