From mboxrd@z Thu Jan 1 00:00:00 1970 From: ww9210 Subject: [PATCH bpf] bpf: Fix integer overflow in queue_stack_map_alloc. Date: Fri, 23 Nov 2018 00:35:19 +0800 Message-ID: <20181122163519.7299-1-ww9210@gmail.com> Cc: Daniel Borkmann , netdev , Eric Dumazet , Greg KH , ww9210 To: Alexei Starovoitov Return-path: Received: from mail-pl1-f193.google.com ([209.85.214.193]:38145 "EHLO mail-pl1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388792AbeKWDPs (ORCPT ); Thu, 22 Nov 2018 22:15:48 -0500 Received: by mail-pl1-f193.google.com with SMTP id e5so9467044plb.5 for ; Thu, 22 Nov 2018 08:35:42 -0800 (PST) Sender: netdev-owner@vger.kernel.org List-ID: Integer overflow in queue_stack_map_alloc when calculating size may lead to heap overflow of arbitrary length. The patch fix it by checking whether attr->max_entries+1 < attr->max_entries and bailing out if it is the case. The vulnerability is discovered with the assistance of syzkaller. Reported-by: Wei Wu To: Alexei Starovoitov Cc: Daniel Borkmann Cc: netdev Cc: Eric Dumazet Cc: Greg KH Signed-off-by: Wei Wu --- kernel/bpf/queue_stack_maps.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/bpf/queue_stack_maps.c b/kernel/bpf/queue_stack_maps.c index 8bbd72d3a121..c35a8a4721c8 100644 --- a/kernel/bpf/queue_stack_maps.c +++ b/kernel/bpf/queue_stack_maps.c @@ -67,6 +67,8 @@ static struct bpf_map *queue_stack_map_alloc(union bpf_attr *attr) u64 queue_size, cost; size = attr->max_entries + 1; + if (size < attr->max_entries) + return ERR_PTR(-EINVAL); value_size = attr->value_size; queue_size = sizeof(*qs) + (u64) value_size * size; -- 2.17.1