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authorPablo Neira Ayuso <pablo@netfilter.org>2017-12-30 22:41:46 +0100
committerPablo Neira Ayuso <pablo@netfilter.org>2018-01-08 18:11:04 +0100
commita7f87b47e67e4341f6175cdb80e5c2eaadf30dcb (patch)
tree47f8be7118f28a8d3f4920968c96d3cb596d7ef2 /net/ipv4/netfilter
parentf6931f5f5b713705c3cc91e4f9c222f2b181e2ef (diff)
netfilter: remove defensive check on malformed packets from raw sockets
Users cannot forge malformed IPv4/IPv6 headers via raw sockets that they can inject into the stack. Specifically, not for IPv4 since 55888dfb6ba7 ("AF_RAW: Augment raw_send_hdrinc to expand skb to fit iphdr->ihl (v2)"). IPv6 raw sockets also ensure that packets have a well-formed IPv6 header available in the skbuff. At quick glance, br_netfilter also validates layer 3 headers and it drops malformed both IPv4 and IPv6 packets. Therefore, let's remove this defensive check all over the place. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/ipv4/netfilter')
-rw-r--r--net/ipv4/netfilter/iptable_filter.c6
-rw-r--r--net/ipv4/netfilter/iptable_mangle.c5
-rw-r--r--net/ipv4/netfilter/iptable_raw.c6
-rw-r--r--net/ipv4/netfilter/iptable_security.c6
-rw-r--r--net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c5
-rw-r--r--net/ipv4/netfilter/nf_nat_l3proto_ipv4.c10
-rw-r--r--net/ipv4/netfilter/nf_tables_ipv4.c17
-rw-r--r--net/ipv4/netfilter/nft_chain_route_ipv4.c5
8 files changed, 1 insertions, 59 deletions
diff --git a/net/ipv4/netfilter/iptable_filter.c b/net/ipv4/netfilter/iptable_filter.c
index 7667f223d7f8..9ac92ea7b93c 100644
--- a/net/ipv4/netfilter/iptable_filter.c
+++ b/net/ipv4/netfilter/iptable_filter.c
@@ -38,12 +38,6 @@ static unsigned int
iptable_filter_hook(void *priv, struct sk_buff *skb,
const struct nf_hook_state *state)
{
- if (state->hook == NF_INET_LOCAL_OUT &&
- (skb->len < sizeof(struct iphdr) ||
- ip_hdrlen(skb) < sizeof(struct iphdr)))
- /* root is playing with raw sockets. */
- return NF_ACCEPT;
-
return ipt_do_table(skb, state, state->net->ipv4.iptable_filter);
}
diff --git a/net/ipv4/netfilter/iptable_mangle.c b/net/ipv4/netfilter/iptable_mangle.c
index aebdb337fd7e..dea138ca8925 100644
--- a/net/ipv4/netfilter/iptable_mangle.c
+++ b/net/ipv4/netfilter/iptable_mangle.c
@@ -49,11 +49,6 @@ ipt_mangle_out(struct sk_buff *skb, const struct nf_hook_state *state)
u_int32_t mark;
int err;
- /* root is playing with raw sockets. */
- if (skb->len < sizeof(struct iphdr) ||
- ip_hdrlen(skb) < sizeof(struct iphdr))
- return NF_ACCEPT;
-
/* Save things which could affect route */
mark = skb->mark;
iph = ip_hdr(skb);
diff --git a/net/ipv4/netfilter/iptable_raw.c b/net/ipv4/netfilter/iptable_raw.c
index 2642ecd2645c..a869d1fea7d9 100644
--- a/net/ipv4/netfilter/iptable_raw.c
+++ b/net/ipv4/netfilter/iptable_raw.c
@@ -26,12 +26,6 @@ static unsigned int
iptable_raw_hook(void *priv, struct sk_buff *skb,
const struct nf_hook_state *state)
{
- if (state->hook == NF_INET_LOCAL_OUT &&
- (skb->len < sizeof(struct iphdr) ||
- ip_hdrlen(skb) < sizeof(struct iphdr)))
- /* root is playing with raw sockets. */
- return NF_ACCEPT;
-
return ipt_do_table(skb, state, state->net->ipv4.iptable_raw);
}
diff --git a/net/ipv4/netfilter/iptable_security.c b/net/ipv4/netfilter/iptable_security.c
index ff226596e4b5..e5379fe57b64 100644
--- a/net/ipv4/netfilter/iptable_security.c
+++ b/net/ipv4/netfilter/iptable_security.c
@@ -43,12 +43,6 @@ static unsigned int
iptable_security_hook(void *priv, struct sk_buff *skb,
const struct nf_hook_state *state)
{
- if (state->hook == NF_INET_LOCAL_OUT &&
- (skb->len < sizeof(struct iphdr) ||
- ip_hdrlen(skb) < sizeof(struct iphdr)))
- /* Somebody is playing with raw sockets. */
- return NF_ACCEPT;
-
return ipt_do_table(skb, state, state->net->ipv4.iptable_security);
}
diff --git a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
index bb2c868a5621..de213a397ea8 100644
--- a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
+++ b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
@@ -154,11 +154,6 @@ static unsigned int ipv4_conntrack_local(void *priv,
struct sk_buff *skb,
const struct nf_hook_state *state)
{
- /* root is playing with raw sockets. */
- if (skb->len < sizeof(struct iphdr) ||
- ip_hdrlen(skb) < sizeof(struct iphdr))
- return NF_ACCEPT;
-
if (ip_is_fragment(ip_hdr(skb))) /* IP_NODEFRAG setsockopt set */
return NF_ACCEPT;
diff --git a/net/ipv4/netfilter/nf_nat_l3proto_ipv4.c b/net/ipv4/netfilter/nf_nat_l3proto_ipv4.c
index 0443ca4120b0..f7ff6a364d7b 100644
--- a/net/ipv4/netfilter/nf_nat_l3proto_ipv4.c
+++ b/net/ipv4/netfilter/nf_nat_l3proto_ipv4.c
@@ -356,11 +356,6 @@ nf_nat_ipv4_out(void *priv, struct sk_buff *skb,
#endif
unsigned int ret;
- /* root is playing with raw sockets. */
- if (skb->len < sizeof(struct iphdr) ||
- ip_hdrlen(skb) < sizeof(struct iphdr))
- return NF_ACCEPT;
-
ret = nf_nat_ipv4_fn(priv, skb, state, do_chain);
#ifdef CONFIG_XFRM
if (ret != NF_DROP && ret != NF_STOLEN &&
@@ -396,11 +391,6 @@ nf_nat_ipv4_local_fn(void *priv, struct sk_buff *skb,
unsigned int ret;
int err;
- /* root is playing with raw sockets. */
- if (skb->len < sizeof(struct iphdr) ||
- ip_hdrlen(skb) < sizeof(struct iphdr))
- return NF_ACCEPT;
-
ret = nf_nat_ipv4_fn(priv, skb, state, do_chain);
if (ret != NF_DROP && ret != NF_STOLEN &&
(ct = nf_ct_get(skb, &ctinfo)) != NULL) {
diff --git a/net/ipv4/netfilter/nf_tables_ipv4.c b/net/ipv4/netfilter/nf_tables_ipv4.c
index 8aeb15c2b9b2..f4675253f1e6 100644
--- a/net/ipv4/netfilter/nf_tables_ipv4.c
+++ b/net/ipv4/netfilter/nf_tables_ipv4.c
@@ -30,21 +30,6 @@ static unsigned int nft_do_chain_ipv4(void *priv,
return nft_do_chain(&pkt, priv);
}
-static unsigned int nft_ipv4_output(void *priv,
- struct sk_buff *skb,
- const struct nf_hook_state *state)
-{
- if (unlikely(skb->len < sizeof(struct iphdr) ||
- ip_hdr(skb)->ihl < sizeof(struct iphdr) / 4)) {
- if (net_ratelimit())
- pr_info("nf_tables_ipv4: ignoring short SOCK_RAW "
- "packet\n");
- return NF_ACCEPT;
- }
-
- return nft_do_chain_ipv4(priv, skb, state);
-}
-
static struct nft_af_info nft_af_ipv4 __read_mostly = {
.family = NFPROTO_IPV4,
.nhooks = NF_INET_NUMHOOKS,
@@ -91,7 +76,7 @@ static const struct nf_chain_type filter_ipv4 = {
(1 << NF_INET_POST_ROUTING),
.hooks = {
[NF_INET_LOCAL_IN] = nft_do_chain_ipv4,
- [NF_INET_LOCAL_OUT] = nft_ipv4_output,
+ [NF_INET_LOCAL_OUT] = nft_do_chain_ipv4,
[NF_INET_FORWARD] = nft_do_chain_ipv4,
[NF_INET_PRE_ROUTING] = nft_do_chain_ipv4,
[NF_INET_POST_ROUTING] = nft_do_chain_ipv4,
diff --git a/net/ipv4/netfilter/nft_chain_route_ipv4.c b/net/ipv4/netfilter/nft_chain_route_ipv4.c
index fb3d49fb62fe..d965c225b9f6 100644
--- a/net/ipv4/netfilter/nft_chain_route_ipv4.c
+++ b/net/ipv4/netfilter/nft_chain_route_ipv4.c
@@ -33,11 +33,6 @@ static unsigned int nf_route_table_hook(void *priv,
const struct iphdr *iph;
int err;
- /* root is playing with raw sockets. */
- if (skb->len < sizeof(struct iphdr) ||
- ip_hdrlen(skb) < sizeof(struct iphdr))
- return NF_ACCEPT;
-
nft_set_pktinfo(&pkt, skb, state);
nft_set_pktinfo_ipv4(&pkt, skb);