4.4-stable review patch. If anyone has any objections, please let me know.
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From: Dmitry Vyukov dvyukov@google.com
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@syzkaller.appspotmail.com Signed-off-by: Dmitry Vyukov dvyukov@google.com Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- 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 @@ -38,8 +38,6 @@ 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)) - struct compat_delta { unsigned int offset; /* offset in kernel */ int delta; /* delta in 32bit user land */ @@ -954,7 +952,7 @@ 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))