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authorPatrick McHardy <kaber@trash.net>2007-07-07 22:36:24 -0700
committerDavid S. Miller <davem@sunset.davemloft.net>2007-07-10 22:18:12 -0700
commitf264a7df08d50bb4a23be6a9aa06940e497ac1c4 (patch)
treec07c92616a50107c2dacc5836626d4b6a12c57ae
parentb560580a13b180bc1e3cad7ffbc93388cc39be5d (diff)
[NETFILTER]: nf_conntrack_expect: introduce nf_conntrack_expect_max sysct
As a last step of preventing DoS by creating lots of expectations, this patch introduces a global maximum and a sysctl to control it. The default is initialized to 4 * the expectation hash table size, which results in 1/64 of the default maxmimum of conntracks. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/net/netfilter/nf_conntrack_expect.h1
-rw-r--r--net/netfilter/nf_conntrack_expect.c10
-rw-r--r--net/netfilter/nf_conntrack_standalone.c9
3 files changed, 19 insertions, 1 deletions
diff --git a/include/net/netfilter/nf_conntrack_expect.h b/include/net/netfilter/nf_conntrack_expect.h
index 9d5af4e22c4..cae1a0dce36 100644
--- a/include/net/netfilter/nf_conntrack_expect.h
+++ b/include/net/netfilter/nf_conntrack_expect.h
@@ -8,6 +8,7 @@
extern struct hlist_head *nf_ct_expect_hash;
extern unsigned int nf_ct_expect_hsize;
+extern unsigned int nf_ct_expect_max;
struct nf_conntrack_expect
{
diff --git a/net/netfilter/nf_conntrack_expect.c b/net/netfilter/nf_conntrack_expect.c
index 5ef0dd439e7..513828fdaa2 100644
--- a/net/netfilter/nf_conntrack_expect.c
+++ b/net/netfilter/nf_conntrack_expect.c
@@ -35,6 +35,7 @@ EXPORT_SYMBOL_GPL(nf_ct_expect_hsize);
static unsigned int nf_ct_expect_hash_rnd __read_mostly;
static unsigned int nf_ct_expect_count;
+unsigned int nf_ct_expect_max __read_mostly;
static int nf_ct_expect_hash_rnd_initted __read_mostly;
static int nf_ct_expect_vmalloc;
@@ -367,6 +368,14 @@ int nf_ct_expect_related(struct nf_conntrack_expect *expect)
master_help->expecting >= master_help->helper->max_expected)
evict_oldest_expect(master);
+ if (nf_ct_expect_count >= nf_ct_expect_max) {
+ if (net_ratelimit())
+ printk(KERN_WARNING
+ "nf_conntrack: expectation table full");
+ ret = -EMFILE;
+ goto out;
+ }
+
nf_ct_expect_insert(expect);
nf_ct_expect_event(IPEXP_NEW, expect);
ret = 0;
@@ -522,6 +531,7 @@ int __init nf_conntrack_expect_init(void)
if (!nf_ct_expect_hsize)
nf_ct_expect_hsize = 1;
}
+ nf_ct_expect_max = nf_ct_expect_hsize * 4;
nf_ct_expect_hash = nf_ct_alloc_hashtable(&nf_ct_expect_hsize,
&nf_ct_expect_vmalloc);
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index 098e7993932..6af96c6e29f 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -372,7 +372,14 @@ static ctl_table nf_ct_sysctl_table[] = {
.extra1 = &log_invalid_proto_min,
.extra2 = &log_invalid_proto_max,
},
-
+ {
+ .ctl_name = CTL_UNNUMBERED,
+ .procname = "nf_conntrack_expect_max",
+ .data = &nf_ct_expect_max,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec,
+ },
{ .ctl_name = 0 }
};