[SRU][Cosmic][Bionic][Xenial][PATCH 1/2] net/af_iucv: drop inbound packets with invalid flags

[Frank Heimes]

From: Julian Wiedmann <jwi at linux.ibm.com>

BugLink: http://bugs.launchpad.net/bugs/1800639

net/af_iucv: drop inbound packets with invalid flags

Inbound packets may have any combination of flag bits set in their iucv
header. If we don't know how to handle a specific combination, drop the
skb instead of leaking it.

To clarify what error is returned in this case, replace the hard-coded
0 with the corresponding macro.

Signed-off-by: Julian Wiedmann <jwi at linux.ibm.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
(cherry-picked from commit 222440996d6daf635bed6cb35041be22ede3e8a0)
Signed-off-by: Frank Heimes <frank.heimes at canonical.com>

---

diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index a21d8ed..01000c1 100644
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -2155,8 +2155,8 @@ static int afiucv_hs_rcv(struct sk_buff *skb, struct
net_device *dev,
        struct sock *sk;
        struct iucv_sock *iucv;
        struct af_iucv_trans_hdr *trans_hdr;
+       int err = NET_RX_SUCCESS;
        char nullstring[8];
-       int err = 0;

        if (skb->len < (ETH_HLEN + sizeof(struct af_iucv_trans_hdr))) {
                WARN_ONCE(1, "AF_IUCV too short skb, len=%d, min=%d",
@@ -2254,7 +2254,7 @@ static int afiucv_hs_rcv(struct sk_buff *skb, struct
net_device *dev,
                err = afiucv_hs_callback_rx(sk, skb);
                break;
        default:
-               ;
+               kfree_skb(skb);
        }

        return err;
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