4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
commit 889c604fd0b5f6d3b8694ade229ee44124de1127 upstream.
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@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/netfilter/x_tables.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -39,8 +39,6 @@ MODULE_LICENSE("GPL");
MODULE_AUTHOR("Harald Welte <laforge@xxxxxxxxxxxxx>");
MODULE_DESCRIPTION("{ip,ip6,arp,eb}_tables backend module");
-#define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
-
struct compat_delta {
unsigned int offset; /* offset in kernel */
int delta; /* delta in 32bit user land */
@@ -952,7 +950,7 @@ struct xt_table_info *xt_alloc_table_inf
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))