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Message-Id: <1459187882-5357-10-git-send-email-pablo@netfilter.org>
Date: Mon, 28 Mar 2016 19:58:02 +0200
From: Pablo Neira Ayuso <pablo@...filter.org>
To: netfilter-devel@...r.kernel.org
Cc: davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 9/9] netfilter: ipv4: fix NULL dereference
From: Liping Zhang <liping.zhang@...eadtrum.com>
Commit fa50d974d104 ("ipv4: Namespaceify ip_default_ttl sysctl knob")
use sock_net(skb->sk) to get the net namespace, but we can't assume
that sk_buff->sk is always exist, so when it is NULL, oops will happen.
Signed-off-by: Liping Zhang <liping.zhang@...eadtrum.com>
Reviewed-by: Nikolay Borisov <kernel@...p.com>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
net/bridge/netfilter/nft_reject_bridge.c | 20 ++++++------
net/ipv4/netfilter/ipt_SYNPROXY.c | 54 +++++++++++++++++---------------
2 files changed, 38 insertions(+), 36 deletions(-)
diff --git a/net/bridge/netfilter/nft_reject_bridge.c b/net/bridge/netfilter/nft_reject_bridge.c
index adc8d72..77f7e7a 100644
--- a/net/bridge/netfilter/nft_reject_bridge.c
+++ b/net/bridge/netfilter/nft_reject_bridge.c
@@ -40,7 +40,8 @@ static void nft_reject_br_push_etherhdr(struct sk_buff *oldskb,
/* We cannot use oldskb->dev, it can be either bridge device (NF_BRIDGE INPUT)
* or the bridge port (NF_BRIDGE PREROUTING).
*/
-static void nft_reject_br_send_v4_tcp_reset(struct sk_buff *oldskb,
+static void nft_reject_br_send_v4_tcp_reset(struct net *net,
+ struct sk_buff *oldskb,
const struct net_device *dev,
int hook)
{
@@ -48,7 +49,6 @@ static void nft_reject_br_send_v4_tcp_reset(struct sk_buff *oldskb,
struct iphdr *niph;
const struct tcphdr *oth;
struct tcphdr _oth;
- struct net *net = sock_net(oldskb->sk);
if (!nft_bridge_iphdr_validate(oldskb))
return;
@@ -75,7 +75,8 @@ static void nft_reject_br_send_v4_tcp_reset(struct sk_buff *oldskb,
br_deliver(br_port_get_rcu(dev), nskb);
}
-static void nft_reject_br_send_v4_unreach(struct sk_buff *oldskb,
+static void nft_reject_br_send_v4_unreach(struct net *net,
+ struct sk_buff *oldskb,
const struct net_device *dev,
int hook, u8 code)
{
@@ -86,7 +87,6 @@ static void nft_reject_br_send_v4_unreach(struct sk_buff *oldskb,
void *payload;
__wsum csum;
u8 proto;
- struct net *net = sock_net(oldskb->sk);
if (oldskb->csum_bad || !nft_bridge_iphdr_validate(oldskb))
return;
@@ -273,17 +273,17 @@ static void nft_reject_bridge_eval(const struct nft_expr *expr,
case htons(ETH_P_IP):
switch (priv->type) {
case NFT_REJECT_ICMP_UNREACH:
- nft_reject_br_send_v4_unreach(pkt->skb, pkt->in,
- pkt->hook,
+ nft_reject_br_send_v4_unreach(pkt->net, pkt->skb,
+ pkt->in, pkt->hook,
priv->icmp_code);
break;
case NFT_REJECT_TCP_RST:
- nft_reject_br_send_v4_tcp_reset(pkt->skb, pkt->in,
- pkt->hook);
+ nft_reject_br_send_v4_tcp_reset(pkt->net, pkt->skb,
+ pkt->in, pkt->hook);
break;
case NFT_REJECT_ICMPX_UNREACH:
- nft_reject_br_send_v4_unreach(pkt->skb, pkt->in,
- pkt->hook,
+ nft_reject_br_send_v4_unreach(pkt->net, pkt->skb,
+ pkt->in, pkt->hook,
nft_reject_icmp_code(priv->icmp_code));
break;
}
diff --git a/net/ipv4/netfilter/ipt_SYNPROXY.c b/net/ipv4/netfilter/ipt_SYNPROXY.c
index 7b8fbb3..db5b875 100644
--- a/net/ipv4/netfilter/ipt_SYNPROXY.c
+++ b/net/ipv4/netfilter/ipt_SYNPROXY.c
@@ -18,10 +18,10 @@
#include <net/netfilter/nf_conntrack_synproxy.h>
static struct iphdr *
-synproxy_build_ip(struct sk_buff *skb, __be32 saddr, __be32 daddr)
+synproxy_build_ip(struct net *net, struct sk_buff *skb, __be32 saddr,
+ __be32 daddr)
{
struct iphdr *iph;
- struct net *net = sock_net(skb->sk);
skb_reset_network_header(skb);
iph = (struct iphdr *)skb_put(skb, sizeof(*iph));
@@ -40,14 +40,12 @@ synproxy_build_ip(struct sk_buff *skb, __be32 saddr, __be32 daddr)
}
static void
-synproxy_send_tcp(const struct synproxy_net *snet,
+synproxy_send_tcp(struct net *net,
const struct sk_buff *skb, struct sk_buff *nskb,
struct nf_conntrack *nfct, enum ip_conntrack_info ctinfo,
struct iphdr *niph, struct tcphdr *nth,
unsigned int tcp_hdr_size)
{
- struct net *net = nf_ct_net(snet->tmpl);
-
nth->check = ~tcp_v4_check(tcp_hdr_size, niph->saddr, niph->daddr, 0);
nskb->ip_summed = CHECKSUM_PARTIAL;
nskb->csum_start = (unsigned char *)nth - nskb->head;
@@ -72,7 +70,7 @@ free_nskb:
}
static void
-synproxy_send_client_synack(const struct synproxy_net *snet,
+synproxy_send_client_synack(struct net *net,
const struct sk_buff *skb, const struct tcphdr *th,
const struct synproxy_options *opts)
{
@@ -91,7 +89,7 @@ synproxy_send_client_synack(const struct synproxy_net *snet,
return;
skb_reserve(nskb, MAX_TCP_HEADER);
- niph = synproxy_build_ip(nskb, iph->daddr, iph->saddr);
+ niph = synproxy_build_ip(net, nskb, iph->daddr, iph->saddr);
skb_reset_transport_header(nskb);
nth = (struct tcphdr *)skb_put(nskb, tcp_hdr_size);
@@ -109,15 +107,16 @@ synproxy_send_client_synack(const struct synproxy_net *snet,
synproxy_build_options(nth, opts);
- synproxy_send_tcp(snet, skb, nskb, skb->nfct, IP_CT_ESTABLISHED_REPLY,
+ synproxy_send_tcp(net, skb, nskb, skb->nfct, IP_CT_ESTABLISHED_REPLY,
niph, nth, tcp_hdr_size);
}
static void
-synproxy_send_server_syn(const struct synproxy_net *snet,
+synproxy_send_server_syn(struct net *net,
const struct sk_buff *skb, const struct tcphdr *th,
const struct synproxy_options *opts, u32 recv_seq)
{
+ struct synproxy_net *snet = synproxy_pernet(net);
struct sk_buff *nskb;
struct iphdr *iph, *niph;
struct tcphdr *nth;
@@ -132,7 +131,7 @@ synproxy_send_server_syn(const struct synproxy_net *snet,
return;
skb_reserve(nskb, MAX_TCP_HEADER);
- niph = synproxy_build_ip(nskb, iph->saddr, iph->daddr);
+ niph = synproxy_build_ip(net, nskb, iph->saddr, iph->daddr);
skb_reset_transport_header(nskb);
nth = (struct tcphdr *)skb_put(nskb, tcp_hdr_size);
@@ -153,12 +152,12 @@ synproxy_send_server_syn(const struct synproxy_net *snet,
synproxy_build_options(nth, opts);
- synproxy_send_tcp(snet, skb, nskb, &snet->tmpl->ct_general, IP_CT_NEW,
+ synproxy_send_tcp(net, skb, nskb, &snet->tmpl->ct_general, IP_CT_NEW,
niph, nth, tcp_hdr_size);
}
static void
-synproxy_send_server_ack(const struct synproxy_net *snet,
+synproxy_send_server_ack(struct net *net,
const struct ip_ct_tcp *state,
const struct sk_buff *skb, const struct tcphdr *th,
const struct synproxy_options *opts)
@@ -177,7 +176,7 @@ synproxy_send_server_ack(const struct synproxy_net *snet,
return;
skb_reserve(nskb, MAX_TCP_HEADER);
- niph = synproxy_build_ip(nskb, iph->daddr, iph->saddr);
+ niph = synproxy_build_ip(net, nskb, iph->daddr, iph->saddr);
skb_reset_transport_header(nskb);
nth = (struct tcphdr *)skb_put(nskb, tcp_hdr_size);
@@ -193,11 +192,11 @@ synproxy_send_server_ack(const struct synproxy_net *snet,
synproxy_build_options(nth, opts);
- synproxy_send_tcp(snet, skb, nskb, NULL, 0, niph, nth, tcp_hdr_size);
+ synproxy_send_tcp(net, skb, nskb, NULL, 0, niph, nth, tcp_hdr_size);
}
static void
-synproxy_send_client_ack(const struct synproxy_net *snet,
+synproxy_send_client_ack(struct net *net,
const struct sk_buff *skb, const struct tcphdr *th,
const struct synproxy_options *opts)
{
@@ -215,7 +214,7 @@ synproxy_send_client_ack(const struct synproxy_net *snet,
return;
skb_reserve(nskb, MAX_TCP_HEADER);
- niph = synproxy_build_ip(nskb, iph->saddr, iph->daddr);
+ niph = synproxy_build_ip(net, nskb, iph->saddr, iph->daddr);
skb_reset_transport_header(nskb);
nth = (struct tcphdr *)skb_put(nskb, tcp_hdr_size);
@@ -231,15 +230,16 @@ synproxy_send_client_ack(const struct synproxy_net *snet,
synproxy_build_options(nth, opts);
- synproxy_send_tcp(snet, skb, nskb, skb->nfct, IP_CT_ESTABLISHED_REPLY,
+ synproxy_send_tcp(net, skb, nskb, skb->nfct, IP_CT_ESTABLISHED_REPLY,
niph, nth, tcp_hdr_size);
}
static bool
-synproxy_recv_client_ack(const struct synproxy_net *snet,
+synproxy_recv_client_ack(struct net *net,
const struct sk_buff *skb, const struct tcphdr *th,
struct synproxy_options *opts, u32 recv_seq)
{
+ struct synproxy_net *snet = synproxy_pernet(net);
int mss;
mss = __cookie_v4_check(ip_hdr(skb), th, ntohl(th->ack_seq) - 1);
@@ -255,7 +255,7 @@ synproxy_recv_client_ack(const struct synproxy_net *snet,
if (opts->options & XT_SYNPROXY_OPT_TIMESTAMP)
synproxy_check_timestamp_cookie(opts);
- synproxy_send_server_syn(snet, skb, th, opts, recv_seq);
+ synproxy_send_server_syn(net, skb, th, opts, recv_seq);
return true;
}
@@ -263,7 +263,8 @@ static unsigned int
synproxy_tg4(struct sk_buff *skb, const struct xt_action_param *par)
{
const struct xt_synproxy_info *info = par->targinfo;
- struct synproxy_net *snet = synproxy_pernet(par->net);
+ struct net *net = par->net;
+ struct synproxy_net *snet = synproxy_pernet(net);
struct synproxy_options opts = {};
struct tcphdr *th, _th;
@@ -292,12 +293,12 @@ synproxy_tg4(struct sk_buff *skb, const struct xt_action_param *par)
XT_SYNPROXY_OPT_SACK_PERM |
XT_SYNPROXY_OPT_ECN);
- synproxy_send_client_synack(snet, skb, th, &opts);
+ synproxy_send_client_synack(net, skb, th, &opts);
return NF_DROP;
} else if (th->ack && !(th->fin || th->rst || th->syn)) {
/* ACK from client */
- synproxy_recv_client_ack(snet, skb, th, &opts, ntohl(th->seq));
+ synproxy_recv_client_ack(net, skb, th, &opts, ntohl(th->seq));
return NF_DROP;
}
@@ -308,7 +309,8 @@ static unsigned int ipv4_synproxy_hook(void *priv,
struct sk_buff *skb,
const struct nf_hook_state *nhs)
{
- struct synproxy_net *snet = synproxy_pernet(nhs->net);
+ struct net *net = nhs->net;
+ struct synproxy_net *snet = synproxy_pernet(net);
enum ip_conntrack_info ctinfo;
struct nf_conn *ct;
struct nf_conn_synproxy *synproxy;
@@ -365,7 +367,7 @@ static unsigned int ipv4_synproxy_hook(void *priv,
* therefore we need to add 1 to make the SYN sequence
* number match the one of first SYN.
*/
- if (synproxy_recv_client_ack(snet, skb, th, &opts,
+ if (synproxy_recv_client_ack(net, skb, th, &opts,
ntohl(th->seq) + 1))
this_cpu_inc(snet->stats->cookie_retrans);
@@ -391,12 +393,12 @@ static unsigned int ipv4_synproxy_hook(void *priv,
XT_SYNPROXY_OPT_SACK_PERM);
swap(opts.tsval, opts.tsecr);
- synproxy_send_server_ack(snet, state, skb, th, &opts);
+ synproxy_send_server_ack(net, state, skb, th, &opts);
nf_ct_seqadj_init(ct, ctinfo, synproxy->isn - ntohl(th->seq));
swap(opts.tsval, opts.tsecr);
- synproxy_send_client_ack(snet, skb, th, &opts);
+ synproxy_send_client_ack(net, skb, th, &opts);
consume_skb(skb);
return NF_STOLEN;
--
2.1.4
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