This is a note to let you know that I've just added the patch titled
netfilter: ebtables: Fixes dropping of small packets in bridge nat
to the 5.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
netfilter-ebtables-fixes-dropping-of-small-packets-i.patch
and it can be found in the queue-5.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 71b90935642274c262f11e30568fa1bc8bc2c2b2
Author: Timothée COCAULT <timothee.cocault@xxxxxxxxxx>
Date: Wed Oct 14 12:36:15 2020 +0000
netfilter: ebtables: Fixes dropping of small packets in bridge nat
[ Upstream commit 63137bc5882a1882c553d389fdeeeace86ee1741 ]
Fixes an error causing small packets to get dropped. skb_ensure_writable
expects the second parameter to be a length in the ethernet payload.=20
If we want to write the ethernet header (src, dst), we should pass 0.
Otherwise, packets with small payloads (< ETH_ALEN) will get dropped.
Fixes: c1a831167901 ("netfilter: bridge: convert skb_make_writable to skb_ensure_writable")
Signed-off-by: Timothée COCAULT <timothee.cocault@xxxxxxxxxx>
Reviewed-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/bridge/netfilter/ebt_dnat.c b/net/bridge/netfilter/ebt_dnat.c
index 12a4f4d936810..3fda71a8579d1 100644
--- a/net/bridge/netfilter/ebt_dnat.c
+++ b/net/bridge/netfilter/ebt_dnat.c
@@ -21,7 +21,7 @@ ebt_dnat_tg(struct sk_buff *skb, const struct xt_action_param *par)
{
const struct ebt_nat_info *info = par->targinfo;
- if (skb_ensure_writable(skb, ETH_ALEN))
+ if (skb_ensure_writable(skb, 0))
return EBT_DROP;
ether_addr_copy(eth_hdr(skb)->h_dest, info->mac);
diff --git a/net/bridge/netfilter/ebt_redirect.c b/net/bridge/netfilter/ebt_redirect.c
index 0cad62a4052b9..307790562b492 100644
--- a/net/bridge/netfilter/ebt_redirect.c
+++ b/net/bridge/netfilter/ebt_redirect.c
@@ -21,7 +21,7 @@ ebt_redirect_tg(struct sk_buff *skb, const struct xt_action_param *par)
{
const struct ebt_redirect_info *info = par->targinfo;
- if (skb_ensure_writable(skb, ETH_ALEN))
+ if (skb_ensure_writable(skb, 0))
return EBT_DROP;
if (xt_hooknum(par) != NF_BR_BROUTING)
diff --git a/net/bridge/netfilter/ebt_snat.c b/net/bridge/netfilter/ebt_snat.c
index 27443bf229a3b..7dfbcdfc30e5d 100644
--- a/net/bridge/netfilter/ebt_snat.c
+++ b/net/bridge/netfilter/ebt_snat.c
@@ -22,7 +22,7 @@ ebt_snat_tg(struct sk_buff *skb, const struct xt_action_param *par)
{
const struct ebt_nat_info *info = par->targinfo;
- if (skb_ensure_writable(skb, ETH_ALEN * 2))
+ if (skb_ensure_writable(skb, 0))
return EBT_DROP;
ether_addr_copy(eth_hdr(skb)->h_source, info->mac);
