netfilter: x_tables: cap allocations at 512 mbyte

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>
This commit is contained in:
Florian Westphal 2018-02-27 19:42:31 +01:00 committed by Greg Kroah-Hartman
parent 89f3232c39
commit fab0b3ce67

View File

@ -40,6 +40,7 @@ MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
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 */
@ -1031,7 +1032,7 @@ struct xt_table_info *xt_alloc_table_info(unsigned int size)
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;
/* Pedantry: prevent them from hitting BUG() in vmalloc.c --RR */