netdev.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Cc: davem@davemloft.net, netdev@vger.kernel.org, kuba@kernel.org
Subject: [PATCH 4/7] netfilter: ebtables: Fixes dropping of small packets in bridge nat
Date: Thu, 22 Oct 2020 19:29:22 +0200	[thread overview]
Message-ID: <20201022172925.22770-5-pablo@netfilter.org> (raw)
In-Reply-To: <20201022172925.22770-1-pablo@netfilter.org>

From: Timothée COCAULT <timothee.cocault@orange.com>

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@orange.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/bridge/netfilter/ebt_dnat.c     | 2 +-
 net/bridge/netfilter/ebt_redirect.c | 2 +-
 net/bridge/netfilter/ebt_snat.c     | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/bridge/netfilter/ebt_dnat.c b/net/bridge/netfilter/ebt_dnat.c
index 12a4f4d93681..3fda71a8579d 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 0cad62a4052b..307790562b49 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 27443bf229a3..7dfbcdfc30e5 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);
-- 
2.20.1


  parent reply	other threads:[~2020-10-22 17:29 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-22 17:29 [PATCH 0/7] Netfilter fixes for net Pablo Neira Ayuso
2020-10-22 17:29 ` [PATCH 1/7] ipvs: adjust the debug info in function set_tcp_state Pablo Neira Ayuso
2020-10-22 19:20   ` patchwork-bot+netdevbpf
2020-10-22 17:29 ` [PATCH 2/7] netfilter: conntrack: connection timeout after re-register Pablo Neira Ayuso
2020-10-22 17:29 ` [PATCH 3/7] netfilter: Drop fragmented ndisc packets assembled in netfilter Pablo Neira Ayuso
2020-10-22 17:29 ` Pablo Neira Ayuso [this message]
2020-10-22 17:29 ` [PATCH 5/7] docs: nf_flowtable: fix typo Pablo Neira Ayuso
2020-10-22 17:29 ` [PATCH 6/7] netfilter: nftables_offload: KASAN slab-out-of-bounds Read in nft_flow_rule_create Pablo Neira Ayuso
2020-10-22 17:29 ` [PATCH 7/7] netfilter: nf_fwd_netdev: clear timestamp in forwarding path Pablo Neira Ayuso
2020-10-22 19:16 ` [PATCH 0/7] Netfilter fixes for net Jakub Kicinski

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20201022172925.22770-5-pablo@netfilter.org \
    --to=pablo@netfilter.org \
    --cc=davem@davemloft.net \
    --cc=kuba@kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=netfilter-devel@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).