[ Upstream commit 7098356b ]

Coverity says:
*** CID 1338065:  Error handling issues  (CHECKED_RETURN)
/net/tipc/udp_media.c: 162 in tipc_udp_send_msg()
156             struct udp_media_addr *dst = (struct udp_media_addr *)&dest->value;
157             struct udp_media_addr *src = (struct udp_media_addr *)&b->addr.value;
158             struct sk_buff *clone;
159             struct rtable *rt;
160
161             if (skb_headroom(skb) < UDP_MIN_HEADROOM)
>>>     CID 1338065:  Error handling issues  (CHECKED_RETURN)
>>>     Calling "pskb_expand_head" without checking return value (as is done elsewhere 51 out of 56
+times).
162                     pskb_expand_head(skb, UDP_MIN_HEADROOM, 0, GFP_ATOMIC);
163
164             clone = skb_clone(skb, GFP_ATOMIC);
165             skb_set_inner_protocol(clone, htons(ETH_P_TIPC));
166             ub = rcu_dereference_rtnl(b->media_ptr);
167             if (!ub) {

When expanding buffer headroom over udp tunnel with pskb_expand_head(),
it's unfortunate that we don't check its return value. As a result, if
the function returns an error code due to the lack of memory, it may
cause unpredictable consequence as we unconditionally consider that
it's always successful.

Fixes: e5356794 ("tipc: conditionally expand buffer headroom over udp tunnel")
Reported-by: <scan-admin@coverity.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>