netfilter-devel.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
Subject: [PATCH 1/7] netfilter: nft_reject: restrict to INPUT/FORWARD/OUTPUT
Date: Tue, 30 Aug 2016 13:26:17 +0200	[thread overview]
Message-ID: <1472556383-6787-2-git-send-email-pablo@netfilter.org> (raw)
In-Reply-To: <1472556383-6787-1-git-send-email-pablo@netfilter.org>

From: Liping Zhang <liping.zhang@spreadtrum.com>

After I add the nft rule "nft add rule filter prerouting reject
with tcp reset", kernel panic happened on my system:
  NULL pointer dereference at ...
  IP: [<ffffffff81b9db2f>] nf_send_reset+0xaf/0x400
  Call Trace:
  [<ffffffff81b9da80>] ? nf_reject_ip_tcphdr_get+0x160/0x160
  [<ffffffffa0928061>] nft_reject_ipv4_eval+0x61/0xb0 [nft_reject_ipv4]
  [<ffffffffa08e836a>] nft_do_chain+0x1fa/0x890 [nf_tables]
  [<ffffffffa08e8170>] ? __nft_trace_packet+0x170/0x170 [nf_tables]
  [<ffffffffa06e0900>] ? nf_ct_invert_tuple+0xb0/0xc0 [nf_conntrack]
  [<ffffffffa07224d4>] ? nf_nat_setup_info+0x5d4/0x650 [nf_nat]
  [...]

Because in the PREROUTING chain, routing information is not exist,
then we will dereference the NULL pointer and oops happen.

So we restrict reject expression to INPUT, FORWARD and OUTPUT chain.
This is consistent with iptables REJECT target.

Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 include/net/netfilter/nft_reject.h   |  4 ++++
 net/ipv4/netfilter/nft_reject_ipv4.c |  1 +
 net/ipv6/netfilter/nft_reject_ipv6.c |  1 +
 net/netfilter/nft_reject.c           | 16 ++++++++++++++++
 net/netfilter/nft_reject_inet.c      |  7 ++++++-
 5 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/include/net/netfilter/nft_reject.h b/include/net/netfilter/nft_reject.h
index 60fa153..02e28c5 100644
--- a/include/net/netfilter/nft_reject.h
+++ b/include/net/netfilter/nft_reject.h
@@ -8,6 +8,10 @@ struct nft_reject {
 
 extern const struct nla_policy nft_reject_policy[];
 
+int nft_reject_validate(const struct nft_ctx *ctx,
+			const struct nft_expr *expr,
+			const struct nft_data **data);
+
 int nft_reject_init(const struct nft_ctx *ctx,
 		    const struct nft_expr *expr,
 		    const struct nlattr * const tb[]);
diff --git a/net/ipv4/netfilter/nft_reject_ipv4.c b/net/ipv4/netfilter/nft_reject_ipv4.c
index c24f41c..2c2553b 100644
--- a/net/ipv4/netfilter/nft_reject_ipv4.c
+++ b/net/ipv4/netfilter/nft_reject_ipv4.c
@@ -46,6 +46,7 @@ static const struct nft_expr_ops nft_reject_ipv4_ops = {
 	.eval		= nft_reject_ipv4_eval,
 	.init		= nft_reject_init,
 	.dump		= nft_reject_dump,
+	.validate	= nft_reject_validate,
 };
 
 static struct nft_expr_type nft_reject_ipv4_type __read_mostly = {
diff --git a/net/ipv6/netfilter/nft_reject_ipv6.c b/net/ipv6/netfilter/nft_reject_ipv6.c
index 533cd57..92bda99 100644
--- a/net/ipv6/netfilter/nft_reject_ipv6.c
+++ b/net/ipv6/netfilter/nft_reject_ipv6.c
@@ -47,6 +47,7 @@ static const struct nft_expr_ops nft_reject_ipv6_ops = {
 	.eval		= nft_reject_ipv6_eval,
 	.init		= nft_reject_init,
 	.dump		= nft_reject_dump,
+	.validate	= nft_reject_validate,
 };
 
 static struct nft_expr_type nft_reject_ipv6_type __read_mostly = {
diff --git a/net/netfilter/nft_reject.c b/net/netfilter/nft_reject.c
index 0522fc9..c64de3f7 100644
--- a/net/netfilter/nft_reject.c
+++ b/net/netfilter/nft_reject.c
@@ -26,11 +26,27 @@ const struct nla_policy nft_reject_policy[NFTA_REJECT_MAX + 1] = {
 };
 EXPORT_SYMBOL_GPL(nft_reject_policy);
 
+int nft_reject_validate(const struct nft_ctx *ctx,
+			const struct nft_expr *expr,
+			const struct nft_data **data)
+{
+	return nft_chain_validate_hooks(ctx->chain,
+					(1 << NF_INET_LOCAL_IN) |
+					(1 << NF_INET_FORWARD) |
+					(1 << NF_INET_LOCAL_OUT));
+}
+EXPORT_SYMBOL_GPL(nft_reject_validate);
+
 int nft_reject_init(const struct nft_ctx *ctx,
 		    const struct nft_expr *expr,
 		    const struct nlattr * const tb[])
 {
 	struct nft_reject *priv = nft_expr_priv(expr);
+	int err;
+
+	err = nft_reject_validate(ctx, expr, NULL);
+	if (err < 0)
+		return err;
 
 	if (tb[NFTA_REJECT_TYPE] == NULL)
 		return -EINVAL;
diff --git a/net/netfilter/nft_reject_inet.c b/net/netfilter/nft_reject_inet.c
index 759ca52..e79d9ca 100644
--- a/net/netfilter/nft_reject_inet.c
+++ b/net/netfilter/nft_reject_inet.c
@@ -66,7 +66,11 @@ static int nft_reject_inet_init(const struct nft_ctx *ctx,
 				const struct nlattr * const tb[])
 {
 	struct nft_reject *priv = nft_expr_priv(expr);
-	int icmp_code;
+	int icmp_code, err;
+
+	err = nft_reject_validate(ctx, expr, NULL);
+	if (err < 0)
+		return err;
 
 	if (tb[NFTA_REJECT_TYPE] == NULL)
 		return -EINVAL;
@@ -124,6 +128,7 @@ static const struct nft_expr_ops nft_reject_inet_ops = {
 	.eval		= nft_reject_inet_eval,
 	.init		= nft_reject_inet_init,
 	.dump		= nft_reject_inet_dump,
+	.validate	= nft_reject_validate,
 };
 
 static struct nft_expr_type nft_reject_inet_type __read_mostly = {
-- 
2.1.4


  reply	other threads:[~2016-08-30 11:26 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-30 11:26 [PATCH 0/7] Netfilter fixes for net Pablo Neira Ayuso
2016-08-30 11:26 ` Pablo Neira Ayuso [this message]
2016-08-30 11:26 ` [PATCH 2/7] netfilter: nfnetlink: use list_for_each_entry_safe to delete all objects Pablo Neira Ayuso
2016-08-30 11:26 ` [PATCH 3/7] netfilter: cttimeout: put back l4proto when replacing timeout policy Pablo Neira Ayuso
2016-08-30 11:26 ` [PATCH 4/7] netfilter: cttimeout: unlink timeout objs in the unconfirmed ct lists Pablo Neira Ayuso
2016-08-30 11:26 ` [PATCH 5/7] netfilter: nft_meta: improve the validity check of pkttype set expr Pablo Neira Ayuso
2016-08-30 11:26 ` [PATCH 6/7] netfilter: ebtables: put module reference when an incorrect extension is found Pablo Neira Ayuso
2016-08-30 11:26 ` [PATCH 7/7] netfilter: nf_tables_netdev: remove redundant ip_hdr assignment Pablo Neira Ayuso
2016-08-31  5:02 ` [PATCH 0/7] 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=1472556383-6787-2-git-send-email-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).