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Subject[PATCH 4.14 175/183] netfilter: x_tables: add counters allocation wrapper
Date
4.14-stable review patch.  If anyone has any objections, please let me know.

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

From: Florian Westphal <fw@strlen.de>

commit c84ca954ac9fa67a6ce27f91f01e4451c74fd8f6 upstream.

allows to have size checks in a single spot.
This is supposed to reduce oom situations when fuzz-testing xtables.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
include/linux/netfilter/x_tables.h | 1 +
net/ipv4/netfilter/arp_tables.c | 2 +-
net/ipv4/netfilter/ip_tables.c | 2 +-
net/ipv6/netfilter/ip6_tables.c | 2 +-
net/netfilter/x_tables.c | 15 +++++++++++++++
5 files changed, 19 insertions(+), 3 deletions(-)

--- a/include/linux/netfilter/x_tables.h
+++ b/include/linux/netfilter/x_tables.h
@@ -301,6 +301,7 @@ int xt_data_to_user(void __user *dst, co

void *xt_copy_counters_from_user(const void __user *user, unsigned int len,
struct xt_counters_info *info, bool compat);
+struct xt_counters *xt_counters_alloc(unsigned int counters);

struct xt_table *xt_register_table(struct net *net,
const struct xt_table *table,
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -883,7 +883,7 @@ static int __do_replace(struct net *net,
struct arpt_entry *iter;

ret = 0;
- counters = vzalloc(num_counters * sizeof(struct xt_counters));
+ counters = xt_counters_alloc(num_counters);
if (!counters) {
ret = -ENOMEM;
goto out;
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -1044,7 +1044,7 @@ __do_replace(struct net *net, const char
struct ipt_entry *iter;

ret = 0;
- counters = vzalloc(num_counters * sizeof(struct xt_counters));
+ counters = xt_counters_alloc(num_counters);
if (!counters) {
ret = -ENOMEM;
goto out;
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -1063,7 +1063,7 @@ __do_replace(struct net *net, const char
struct ip6t_entry *iter;

ret = 0;
- counters = vzalloc(num_counters * sizeof(struct xt_counters));
+ counters = xt_counters_alloc(num_counters);
if (!counters) {
ret = -ENOMEM;
goto out;
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -1187,6 +1187,21 @@ static int xt_jumpstack_alloc(struct xt_
return 0;
}

+struct xt_counters *xt_counters_alloc(unsigned int counters)
+{
+ struct xt_counters *mem;
+
+ if (counters == 0 || counters > INT_MAX / sizeof(*mem))
+ return NULL;
+
+ counters *= sizeof(*mem);
+ if (counters > XT_MAX_TABLE_SIZE)
+ return NULL;
+
+ return vzalloc(counters);
+}
+EXPORT_SYMBOL(xt_counters_alloc);
+
struct xt_table_info *
xt_replace_table(struct xt_table *table,
unsigned int num_counters,

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