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Subject[ 84/89] netfilter: xt_recent: avoid high order page allocations
Date
3.7-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Eric Dumazet <edumazet@google.com>

commit 2727de76041b2064c0b74f00a2a89678fb3efafc upstream.

xt_recent can try high order page allocations and this can fail.

iptables: page allocation failure: order:9, mode:0xc0d0

It also wastes about half the allocated space because of kmalloc()
power-of-two roundups and struct recent_table layout.

Use vmalloc() instead to save space and be less prone to allocation
errors when memory is fragmented.

Reported-by: Miroslav Kratochvil <exa.exa@gmail.com>
Reported-by: Dave Jones <davej@redhat.com>
Reported-by: Harald Reindl <h.reindl@thelounge.net>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
net/netfilter/xt_recent.c | 23 ++++++++++++++++++-----
1 file changed, 18 insertions(+), 5 deletions(-)

--- a/net/netfilter/xt_recent.c
+++ b/net/netfilter/xt_recent.c
@@ -29,6 +29,7 @@
#include <linux/skbuff.h>
#include <linux/inet.h>
#include <linux/slab.h>
+#include <linux/vmalloc.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>

@@ -310,6 +311,14 @@ out:
return ret;
}

+static void recent_table_free(void *addr)
+{
+ if (is_vmalloc_addr(addr))
+ vfree(addr);
+ else
+ kfree(addr);
+}
+
static int recent_mt_check(const struct xt_mtchk_param *par,
const struct xt_recent_mtinfo_v1 *info)
{
@@ -322,6 +331,7 @@ static int recent_mt_check(const struct
#endif
unsigned int i;
int ret = -EINVAL;
+ size_t sz;

if (unlikely(!hash_rnd_inited)) {
get_random_bytes(&hash_rnd, sizeof(hash_rnd));
@@ -360,8 +370,11 @@ static int recent_mt_check(const struct
goto out;
}

- t = kzalloc(sizeof(*t) + sizeof(t->iphash[0]) * ip_list_hash_size,
- GFP_KERNEL);
+ sz = sizeof(*t) + sizeof(t->iphash[0]) * ip_list_hash_size;
+ if (sz <= PAGE_SIZE)
+ t = kzalloc(sz, GFP_KERNEL);
+ else
+ t = vzalloc(sz);
if (t == NULL) {
ret = -ENOMEM;
goto out;
@@ -377,14 +390,14 @@ static int recent_mt_check(const struct
uid = make_kuid(&init_user_ns, ip_list_uid);
gid = make_kgid(&init_user_ns, ip_list_gid);
if (!uid_valid(uid) || !gid_valid(gid)) {
- kfree(t);
+ recent_table_free(t);
ret = -EINVAL;
goto out;
}
pde = proc_create_data(t->name, ip_list_perms, recent_net->xt_recent,
&recent_mt_fops, t);
if (pde == NULL) {
- kfree(t);
+ recent_table_free(t);
ret = -ENOMEM;
goto out;
}
@@ -435,7 +448,7 @@ static void recent_mt_destroy(const stru
remove_proc_entry(t->name, recent_net->xt_recent);
#endif
recent_table_flush(t);
- kfree(t);
+ recent_table_free(t);
}
mutex_unlock(&recent_mutex);
}



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