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Subject[PATCH 4.16 18/26] netfilter: x_tables: cap allocations at 512 mbyte
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4.16-stable review patch.  If anyone has any objections, please let me know.

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

From: Florian Westphal <fw@strlen.de>

commit 19926968ea86a286aa6fbea16ee3f2e7442f10f0 upstream.

Arbitrary limit, however, this still allows huge rulesets
(> 1 million rules). This helps with automated fuzzer as it prevents
oom-killer invocation.

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>

---
net/netfilter/x_tables.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -40,6 +40,7 @@ MODULE_AUTHOR("Harald Welte <laforge@net
MODULE_DESCRIPTION("{ip,ip6,arp,eb}_tables backend module");

#define XT_PCPU_BLOCK_SIZE 4096
+#define XT_MAX_TABLE_SIZE (512 * 1024 * 1024)

struct compat_delta {
unsigned int offset; /* offset in kernel */
@@ -1029,7 +1030,7 @@ struct xt_table_info *xt_alloc_table_inf
struct xt_table_info *info = NULL;
size_t sz = sizeof(*info) + size;

- if (sz < sizeof(*info))
+ if (sz < sizeof(*info) || sz >= XT_MAX_TABLE_SIZE)
return NULL;

/* __GFP_NORETRY is not fully supported by kvmalloc but it should

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