From: Florian Westphal <fw@strlen.de>
Date: Tue, 27 Feb 2018 18:42:32 +0000 (+0100)
Subject: netfilter: x_tables: limit allocation requests for blob rule heads
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=9d5c12a7c08f67999772065afd50fb222072114e;p=linux.git

netfilter: x_tables: limit allocation requests for blob rule heads

This is a very conservative limit (134217728 rules), but good
enough to not trigger frequent oom from syzkaller.

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

diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index dc68ac49614a9..01f8e122e74ee 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -894,6 +894,9 @@ EXPORT_SYMBOL(xt_check_entry_offsets);
  */
 unsigned int *xt_alloc_entry_offsets(unsigned int size)
 {
+	if (size > XT_MAX_TABLE_SIZE / sizeof(unsigned int))
+		return NULL;
+
 	return kvmalloc_array(size, sizeof(unsigned int), GFP_KERNEL | __GFP_ZERO);
 
 }