Fix "net: ipv4: do not handle duplicate fragments as overlapping"

ade446403bfb ("net: ipv4: do not handle duplicate fragments as
overlapping") was backported to many stable trees, but it had a problem
that was "accidentally" fixed by the upstream commit 0ff89efb5246 ("ip:
fail fast on IP defrag errors")

This is the fixup for that problem as we do not want the larger patch in
the older stable trees.

Fixes: ade446403bfb ("net: ipv4: do not handle duplicate fragments as overlapping")
Reported-by: Ivan Babrou <ivan@cloudflare.com>
Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index f8bbd69..d95b32a 100644 (file)
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -425,6 +425,7 @@ static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
         * fragment.
         */
 
+       err = -EINVAL;
        /* Find out where to put this fragment.  */
        prev_tail = qp->q.fragments_tail;
        if (!prev_tail)
@@ -501,7 +502,6 @@ static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
 
 discard_qp:
        inet_frag_kill(&qp->q);
-       err = -EINVAL;
        __IP_INC_STATS(net, IPSTATS_MIB_REASM_OVERLAPS);
 err:
        kfree_skb(skb);