From: Dmitry Vyukov <dvyukov@google.com>
Subject: netfilter: x_tables: fix int overflow in
xt_alloc_table_info()
Patch-mainline: v4.16-rc1
Git-commit: 889c604fd0b5f6d3b8694ade229ee44124de1127
References: git-fixes
syzkaller triggered OOM kills by passing ipt_replace.size = -1
to IPT_SO_SET_REPLACE. The root cause is that SMP_ALIGN() in
xt_alloc_table_info() causes int overflow and the size check passes
when it should not. SMP_ALIGN() is no longer needed leftover.
Remove SMP_ALIGN() call in xt_alloc_table_info().
Reported-by: syzbot+4396883fa8c4f64e0175@syzkaller.appspotmail.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Denis Kirjanov <dkirjanov@suse.com>
---
net/netfilter/x_tables.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index 2d1d580cf9d0..ed01d01e6871 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -39,7 +39,6 @@ MODULE_LICENSE("GPL");
MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
MODULE_DESCRIPTION("{ip,ip6,arp,eb}_tables backend module");
-#define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
#define XT_PCPU_BLOCK_SIZE 4096
struct compat_delta {
@@ -1000,7 +999,7 @@ struct xt_table_info *xt_alloc_table_info(unsigned int size)
return NULL;
/* Pedantry: prevent them from hitting BUG() in vmalloc.c --RR */
- if ((SMP_ALIGN(size) >> PAGE_SHIFT) + 2 > totalram_pages)
+ if ((size >> PAGE_SHIFT) + 2 > totalram_pages)
return NULL;
if (sz <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER))
--
2.12.3