diff options
| author | Patrick McHardy <kaber@trash.net> | 2007-07-08 07:36:24 +0200 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2007-07-11 07:18:12 +0200 |
| commit | f264a7df08d50bb4a23be6a9aa06940e497ac1c4 (patch) | |
| tree | c07c92616a50107c2dacc5836626d4b6a12c57ae | |
| parent | [NETFILTER]: nf_conntrack_expect: maintain per conntrack expectation list (diff) | |
| download | linux-f264a7df08d50bb4a23be6a9aa06940e497ac1c4.tar.xz linux-f264a7df08d50bb4a23be6a9aa06940e497ac1c4.zip | |
[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.h | 1 | ||||
| -rw-r--r-- | net/netfilter/nf_conntrack_expect.c | 10 | ||||
| -rw-r--r-- | net/netfilter/nf_conntrack_standalone.c | 9 |
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 9d5af4e22c4f..cae1a0dce365 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 5ef0dd439e76..513828fdaa2c 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 098e7993932a..6af96c6e29fb 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 } }; |