From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AB67CC7618B for ; Fri, 26 Jul 2019 15:29:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7684022CB9 for ; Fri, 26 Jul 2019 15:29:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564154994; bh=Rav/C6lgLVHexHCFKIQE8Cujr8Ay/4VVnvxUi+1PEa0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=tDWd6mxsZrJHfbIXw1Gw+6Cz1uMRS8guRRoHgLn0BNmmTxKch1XRAj+bv3kHCfe7V 0xnw6cMWNWPpx5XLgkd1qG7FtAyiruhxerxd+U2s5wdH4of8kSVM88ZqaNtqBjCwwS XEUtkDHzftWdZ8NokZhBesuGCSS5okHq7SCm7luo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388951AbfGZP3x (ORCPT ); Fri, 26 Jul 2019 11:29:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:44580 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388934AbfGZP3v (ORCPT ); Fri, 26 Jul 2019 11:29:51 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 535DF22CB9; Fri, 26 Jul 2019 15:29:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564154989; bh=Rav/C6lgLVHexHCFKIQE8Cujr8Ay/4VVnvxUi+1PEa0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RvbiEDz+E1cZpp8YESDr4txLkHBXEWhtxfxIMpAeseU7mQXMuhpJMYiURQTRGzLA/ yLZfnb/oLZ4ZjKMyUf3o2Loac4vgYETfnCxo9HyANHWvvjIz+QmqskhgYQ704dtoSK 6p+JqUPYPgYzFWUU5NAOP9pUCWCcdcwg0h3BNfPQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Martin Weinelt , Nikolay Aleksandrov , "David S. Miller" Subject: [PATCH 5.1 28/62] net: bridge: mcast: fix stale nsrcs pointer in igmp3/mld2 report handling Date: Fri, 26 Jul 2019 17:24:40 +0200 Message-Id: <20190726152304.673905012@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190726152301.720139286@linuxfoundation.org> References: <20190726152301.720139286@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Nikolay Aleksandrov [ Upstream commit e57f61858b7cf478ed6fa23ed4b3876b1c9625c4 ] We take a pointer to grec prior to calling pskb_may_pull and use it afterwards to get nsrcs so record nsrcs before the pull when handling igmp3 and we get a pointer to nsrcs and call pskb_may_pull when handling mld2 which again could lead to reading 2 bytes out-of-bounds. ================================================================== BUG: KASAN: use-after-free in br_multicast_rcv+0x480c/0x4ad0 [bridge] Read of size 2 at addr ffff8880421302b4 by task ksoftirqd/1/16 CPU: 1 PID: 16 Comm: ksoftirqd/1 Tainted: G OE 5.2.0-rc6+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 Call Trace: dump_stack+0x71/0xab print_address_description+0x6a/0x280 ? br_multicast_rcv+0x480c/0x4ad0 [bridge] __kasan_report+0x152/0x1aa ? br_multicast_rcv+0x480c/0x4ad0 [bridge] ? br_multicast_rcv+0x480c/0x4ad0 [bridge] kasan_report+0xe/0x20 br_multicast_rcv+0x480c/0x4ad0 [bridge] ? br_multicast_disable_port+0x150/0x150 [bridge] ? ktime_get_with_offset+0xb4/0x150 ? __kasan_kmalloc.constprop.6+0xa6/0xf0 ? __netif_receive_skb+0x1b0/0x1b0 ? br_fdb_update+0x10e/0x6e0 [bridge] ? br_handle_frame_finish+0x3c6/0x11d0 [bridge] br_handle_frame_finish+0x3c6/0x11d0 [bridge] ? br_pass_frame_up+0x3a0/0x3a0 [bridge] ? virtnet_probe+0x1c80/0x1c80 [virtio_net] br_handle_frame+0x731/0xd90 [bridge] ? select_idle_sibling+0x25/0x7d0 ? br_handle_frame_finish+0x11d0/0x11d0 [bridge] __netif_receive_skb_core+0xced/0x2d70 ? virtqueue_get_buf_ctx+0x230/0x1130 [virtio_ring] ? do_xdp_generic+0x20/0x20 ? virtqueue_napi_complete+0x39/0x70 [virtio_net] ? virtnet_poll+0x94d/0xc78 [virtio_net] ? receive_buf+0x5120/0x5120 [virtio_net] ? __netif_receive_skb_one_core+0x97/0x1d0 __netif_receive_skb_one_core+0x97/0x1d0 ? __netif_receive_skb_core+0x2d70/0x2d70 ? _raw_write_trylock+0x100/0x100 ? __queue_work+0x41e/0xbe0 process_backlog+0x19c/0x650 ? _raw_read_lock_irq+0x40/0x40 net_rx_action+0x71e/0xbc0 ? __switch_to_asm+0x40/0x70 ? napi_complete_done+0x360/0x360 ? __switch_to_asm+0x34/0x70 ? __switch_to_asm+0x40/0x70 ? __schedule+0x85e/0x14d0 __do_softirq+0x1db/0x5f9 ? takeover_tasklets+0x5f0/0x5f0 run_ksoftirqd+0x26/0x40 smpboot_thread_fn+0x443/0x680 ? sort_range+0x20/0x20 ? schedule+0x94/0x210 ? __kthread_parkme+0x78/0xf0 ? sort_range+0x20/0x20 kthread+0x2ae/0x3a0 ? kthread_create_worker_on_cpu+0xc0/0xc0 ret_from_fork+0x35/0x40 The buggy address belongs to the page: page:ffffea0001084c00 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x0 flags: 0xffffc000000000() raw: 00ffffc000000000 ffffea0000cfca08 ffffea0001098608 0000000000000000 raw: 0000000000000000 0000000000000003 00000000ffffff7f 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888042130180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888042130200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff > ffff888042130280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff888042130300: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888042130380: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== Disabling lock debugging due to kernel taint Fixes: bc8c20acaea1 ("bridge: multicast: treat igmpv3 report with INCLUDE and no sources as a leave") Reported-by: Martin Weinelt Signed-off-by: Nikolay Aleksandrov Tested-by: Martin Weinelt Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/bridge/br_multicast.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -934,6 +934,7 @@ static int br_ip4_multicast_igmp3_report int type; int err = 0; __be32 group; + u16 nsrcs; ih = igmpv3_report_hdr(skb); num = ntohs(ih->ngrec); @@ -947,8 +948,9 @@ static int br_ip4_multicast_igmp3_report grec = (void *)(skb->data + len - sizeof(*grec)); group = grec->grec_mca; type = grec->grec_type; + nsrcs = ntohs(grec->grec_nsrcs); - len += ntohs(grec->grec_nsrcs) * 4; + len += nsrcs * 4; if (!ip_mc_may_pull(skb, len)) return -EINVAL; @@ -969,7 +971,7 @@ static int br_ip4_multicast_igmp3_report src = eth_hdr(skb)->h_source; if ((type == IGMPV3_CHANGE_TO_INCLUDE || type == IGMPV3_MODE_IS_INCLUDE) && - ntohs(grec->grec_nsrcs) == 0) { + nsrcs == 0) { br_ip4_multicast_leave_group(br, port, group, vid, src); } else { err = br_ip4_multicast_add_group(br, port, group, vid, @@ -1006,7 +1008,8 @@ static int br_ip6_multicast_mld2_report( len = skb_transport_offset(skb) + sizeof(*icmp6h); for (i = 0; i < num; i++) { - __be16 *nsrcs, _nsrcs; + __be16 *_nsrcs, __nsrcs; + u16 nsrcs; nsrcs_offset = len + offsetof(struct mld2_grec, grec_nsrcs); @@ -1014,12 +1017,13 @@ static int br_ip6_multicast_mld2_report( nsrcs_offset + sizeof(_nsrcs)) return -EINVAL; - nsrcs = skb_header_pointer(skb, nsrcs_offset, - sizeof(_nsrcs), &_nsrcs); - if (!nsrcs) + _nsrcs = skb_header_pointer(skb, nsrcs_offset, + sizeof(__nsrcs), &__nsrcs); + if (!_nsrcs) return -EINVAL; - grec_len = struct_size(grec, grec_src, ntohs(*nsrcs)); + nsrcs = ntohs(*_nsrcs); + grec_len = struct_size(grec, grec_src, nsrcs); if (!ipv6_mc_may_pull(skb, len + grec_len)) return -EINVAL; @@ -1044,7 +1048,7 @@ static int br_ip6_multicast_mld2_report( src = eth_hdr(skb)->h_source; if ((grec->grec_type == MLD2_CHANGE_TO_INCLUDE || grec->grec_type == MLD2_MODE_IS_INCLUDE) && - ntohs(*nsrcs) == 0) { + nsrcs == 0) { br_ip6_multicast_leave_group(br, port, &grec->grec_mca, vid, src); } else {