diff options
authorFlorian Westphal <fw@strlen.de>2014-05-02 15:32:16 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-06-16 13:42:53 -0700
commited6b7164b4a932f91630da7dadaa1aeb33029d25 (patch)
parent3f3a34d420f0d08d81379c03cc7d258f2f42dc3f (diff)
netfilter: ipv4: defrag: set local_df flag on defragmented skb
commit 895162b1101b3ea5db08ca6822ae9672717efec0 upstream. else we may fail to forward skb even if original fragments do fit outgoing link mtu: 1. remote sends 2k packets in two 1000 byte frags, DF set 2. we want to forward but only see '2k > mtu and DF set' 3. we then send icmp error saying that outgoing link is 1500 But original sender never sent a packet that would not fit the outgoing link. Setting local_df makes outgoing path test size vs. IPCB(skb)->frag_max_size, so we will still send the correct error in case the largest original size did not fit outgoing link mtu. Reported-by: Maxime Bizon <mbizon@freebox.fr> Suggested-by: Maxime Bizon <mbizon@freebox.fr> Fixes: 5f2d04f1f9 (ipv4: fix path MTU discovery with connection tracking) Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Cc: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 3 insertions, 2 deletions
diff --git a/net/ipv4/netfilter/nf_defrag_ipv4.c b/net/ipv4/netfilter/nf_defrag_ipv4.c
index 742815518b0..4cfb3bd1677 100644
--- a/net/ipv4/netfilter/nf_defrag_ipv4.c
+++ b/net/ipv4/netfilter/nf_defrag_ipv4.c
@@ -22,7 +22,6 @@
#include <net/netfilter/nf_conntrack_zones.h>
-/* Returns new sk_buff, or NULL */
static int nf_ct_ipv4_gather_frags(struct sk_buff *skb, u_int32_t user)
int err;
@@ -33,8 +32,10 @@ static int nf_ct_ipv4_gather_frags(struct sk_buff *skb, u_int32_t user)
err = ip_defrag(skb, user);
- if (!err)
+ if (!err) {
+ skb->local_df = 1;
+ }
return err;