From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Cc: davem@davemloft.net, netdev@vger.kernel.org
Subject: [PATCH 2/5] netfilter: seqadj: re-load tcp header pointer after possible head reallocation
Date: Thu, 13 Dec 2018 02:06:28 +0100 [thread overview]
Message-ID: <20181213010631.9753-3-pablo@netfilter.org> (raw)
In-Reply-To: <20181213010631.9753-1-pablo@netfilter.org>
From: Florian Westphal <fw@strlen.de>
When adjusting sack block sequence numbers, skb_make_writable() gets
called to make sure tcp options are all in the linear area, and buffer
is not shared.
This can cause tcp header pointer to get reallocated, so we must
reaload it to avoid memory corruption.
This bug pre-dates git history.
Reported-by: Neel Mehta <nmehta@google.com>
Reported-by: Shane Huntley <shuntley@google.com>
Reported-by: Heather Adkins <argv@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
net/netfilter/nf_conntrack_seqadj.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/net/netfilter/nf_conntrack_seqadj.c b/net/netfilter/nf_conntrack_seqadj.c
index a975efd6b8c3..9da303461069 100644
--- a/net/netfilter/nf_conntrack_seqadj.c
+++ b/net/netfilter/nf_conntrack_seqadj.c
@@ -115,12 +115,12 @@ static void nf_ct_sack_block_adjust(struct sk_buff *skb,
/* TCP SACK sequence number adjustment */
static unsigned int nf_ct_sack_adjust(struct sk_buff *skb,
unsigned int protoff,
- struct tcphdr *tcph,
struct nf_conn *ct,
enum ip_conntrack_info ctinfo)
{
- unsigned int dir, optoff, optend;
+ struct tcphdr *tcph = (void *)skb->data + protoff;
struct nf_conn_seqadj *seqadj = nfct_seqadj(ct);
+ unsigned int dir, optoff, optend;
optoff = protoff + sizeof(struct tcphdr);
optend = protoff + tcph->doff * 4;
@@ -128,6 +128,7 @@ static unsigned int nf_ct_sack_adjust(struct sk_buff *skb,
if (!skb_make_writable(skb, optend))
return 0;
+ tcph = (void *)skb->data + protoff;
dir = CTINFO2DIR(ctinfo);
while (optoff < optend) {
@@ -207,7 +208,7 @@ int nf_ct_seq_adjust(struct sk_buff *skb,
ntohl(newack));
tcph->ack_seq = newack;
- res = nf_ct_sack_adjust(skb, protoff, tcph, ct, ctinfo);
+ res = nf_ct_sack_adjust(skb, protoff, ct, ctinfo);
out:
spin_unlock_bh(&ct->lock);
--
2.11.0
next prev parent reply other threads:[~2018-12-13 1:06 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-13 1:06 [PATCH 0/5] Netfilter fixes for net Pablo Neira Ayuso
2018-12-13 1:06 ` [PATCH 1/5] netfilter: nf_tables: fix suspicious RCU usage in nft_chain_stats_replace() Pablo Neira Ayuso
2018-12-13 1:06 ` Pablo Neira Ayuso [this message]
2018-12-13 1:06 ` [PATCH 3/5] netfilter: ipset: do not call ipset_nest_end after nla_nest_cancel Pablo Neira Ayuso
2018-12-13 1:06 ` [PATCH 4/5] netfilter: nat: can't use dst_hold on noref dst Pablo Neira Ayuso
2018-12-13 1:06 ` [PATCH 5/5] netfilter: nf_conncount: use rb_link_node_rcu() instead of rb_link_node() Pablo Neira Ayuso
2018-12-13 5:37 ` [PATCH 0/5] Netfilter fixes for net David Miller
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=20181213010631.9753-3-pablo@netfilter.org \
--to=pablo@netfilter.org \
--cc=davem@davemloft.net \
--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).