[PATCH] netfilter: xt_recent: avoid high order page allocations
From: Eric Dumazet <hidden>
Date: 2013-01-04 08:18:39
From: Eric Dumazet <edumazet@google.com> 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 <redacted> Reported-by: Dave Jones <redacted> Reported-by: Harald Reindl <redacted> Signed-off-by: Eric Dumazet <edumazet@google.com> --- net/netfilter/xt_recent.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-)
diff --git a/net/netfilter/xt_recent.c b/net/netfilter/xt_recent.c
index dab053e..978efc9 100644
--- 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 xt_mtchk_param *par, #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 xt_mtchk_param *par, 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 xt_mtchk_param *par, 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 struct xt_mtdtor_param *par) remove_proc_entry(t->name, recent_net->xt_recent); #endif recent_table_flush(t); - kfree(t); + recent_table_free(t); } mutex_unlock(&recent_mutex); }