From: Florian Westphal <fw@xxxxxxxxx>
Don't bother testing if we need to switch to alternate stack
unless TEE target is used.
Suggested-by: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
include/linux/netfilter/x_tables.h | 7 +++++++
net/ipv4/netfilter/ip_tables.c | 3 ++-
net/ipv6/netfilter/ip6_tables.c | 3 ++-
net/netfilter/x_tables.c | 3 +++
net/netfilter/xt_TEE.c | 2 ++
5 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h
index 1492845..b006b71 100644
--- a/include/linux/netfilter/x_tables.h
+++ b/include/linux/netfilter/x_tables.h
@@ -3,6 +3,7 @@
#include <linux/netdevice.h>
+#include <linux/static_key.h>
#include <uapi/linux/netfilter/x_tables.h>
/**
@@ -280,6 +281,12 @@ void xt_free_table_info(struct xt_table_info *info);
*/
DECLARE_PER_CPU(seqcount_t, xt_recseq);
+/* xt_tee_enabled - true if x_tables needs to handle reentrancy
+ *
+ * Enabled if current ip(6)tables ruleset has at least one -j TEE rule.
+ */
+extern struct static_key xt_tee_enabled;
+
/**
* xt_write_recseq_begin - start of a write section
*
diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index a2e4b01..ff585bd 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -340,7 +340,8 @@ ipt_do_table(struct sk_buff *skb,
* For recursion via REJECT or SYNPROXY the stack will be clobbered
* but it is no problem since absolute verdict is issued by these.
*/
- jumpstack += private->stacksize * __this_cpu_read(nf_skb_duplicated);
+ if (static_key_false(&xt_tee_enabled))
+ jumpstack += private->stacksize * __this_cpu_read(nf_skb_duplicated);
e = get_entry(table_base, private->hook_entry[hook]);
diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
index 531281f..ea6d105 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -366,7 +366,8 @@ ip6t_do_table(struct sk_buff *skb,
* For recursion via REJECT or SYNPROXY the stack will be clobbered
* but it is no problem since absolute verdict is issued by these.
*/
- jumpstack += private->stacksize * __this_cpu_read(nf_skb_duplicated);
+ if (static_key_false(&xt_tee_enabled))
+ jumpstack += private->stacksize * __this_cpu_read(nf_skb_duplicated);
e = get_entry(table_base, private->hook_entry[hook]);
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index 154447e..9b42b5e 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -727,6 +727,9 @@ EXPORT_SYMBOL_GPL(xt_compat_unlock);
DEFINE_PER_CPU(seqcount_t, xt_recseq);
EXPORT_PER_CPU_SYMBOL_GPL(xt_recseq);
+struct static_key xt_tee_enabled __read_mostly;
+EXPORT_SYMBOL_GPL(xt_tee_enabled);
+
static int xt_jumpstack_alloc(struct xt_table_info *i)
{
unsigned int size;
diff --git a/net/netfilter/xt_TEE.c b/net/netfilter/xt_TEE.c
index 8950e79..c5d6556 100644
--- a/net/netfilter/xt_TEE.c
+++ b/net/netfilter/xt_TEE.c
@@ -251,6 +251,7 @@ static int tee_tg_check(const struct xt_tgchk_param *par)
} else
info->priv = NULL;
+ static_key_slow_inc(&xt_tee_enabled);
return 0;
}
@@ -262,6 +263,7 @@ static void tee_tg_destroy(const struct xt_tgdtor_param *par)
unregister_netdevice_notifier(&info->priv->notifier);
kfree(info->priv);
}
+ static_key_slow_dec(&xt_tee_enabled);
}
static struct xt_target tee_tg_reg[] __read_mostly = {
--
1.7.10.4
--
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