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=-10.0 required=3.0 tests=BAYES_00,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=unavailable 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 E3F8EC433E6 for ; Tue, 1 Sep 2020 16:44:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A3D352067C for ; Tue, 1 Sep 2020 16:44:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598978668; bh=PyOqTXxtUxabTkmpMdkhNJrd1Sig8VNDdxxFv41x27k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=XO8DaqvjDjYp1vnFIopMTD4at0SN07jFa5bjSXiBVhSaiwY6topAEyTkLi4t1upZN MCJKqZM157lS471XCvmV8yMmUlKBfjiKe5aiPW39sg70IpjwrXD87nv50TzahsHRcU PXTaDn/A4H0vaflpkGe5CUXAT01UEfUMuWqCqYuc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730259AbgIAQoZ (ORCPT ); Tue, 1 Sep 2020 12:44:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:54994 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729241AbgIAP1l (ORCPT ); Tue, 1 Sep 2020 11:27:41 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 0EFF2206FA; Tue, 1 Sep 2020 15:27:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598974060; bh=PyOqTXxtUxabTkmpMdkhNJrd1Sig8VNDdxxFv41x27k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CKH+yEHXA0wSze+Gjhr2MV3KTrW7oJ/xbfLLShdklRMOJq7IzVmEqjV+ZvIL9IegJ 0OdVKbne0MOJxeEnPbv7axjR/0PkBC+XmD46CpbxvHe3W6G51XuiamPuoKq6m+YIEW o2ritCyZG8saE7coWJADCK7Eln01hzU6Yc4u7w+4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, David Ahern , syzbot+a61aa19b0c14c8770bd9@syzkaller.appspotmail.com, Nikolay Aleksandrov , "David S. Miller" Subject: [PATCH 5.4 005/214] net: nexthop: dont allow empty NHA_GROUP Date: Tue, 1 Sep 2020 17:08:05 +0200 Message-Id: <20200901150953.214915664@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200901150952.963606936@linuxfoundation.org> References: <20200901150952.963606936@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 eeaac3634ee0e3f35548be35275efeca888e9b23 ] Currently the nexthop code will use an empty NHA_GROUP attribute, but it requires at least 1 entry in order to function properly. Otherwise we end up derefencing null or random pointers all over the place due to not having any nh_grp_entry members allocated, nexthop code relies on having at least the first member present. Empty NHA_GROUP doesn't make any sense so just disallow it. Also add a WARN_ON for any future users of nexthop_create_group(). BUG: kernel NULL pointer dereference, address: 0000000000000080 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] SMP CPU: 0 PID: 558 Comm: ip Not tainted 5.9.0-rc1+ #93 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-2.fc32 04/01/2014 RIP: 0010:fib_check_nexthop+0x4a/0xaa Code: 0f 84 83 00 00 00 48 c7 02 80 03 f7 81 c3 40 80 fe fe 75 12 b8 ea ff ff ff 48 85 d2 74 6b 48 c7 02 40 03 f7 81 c3 48 8b 40 10 <48> 8b 80 80 00 00 00 eb 36 80 78 1a 00 74 12 b8 ea ff ff ff 48 85 RSP: 0018:ffff88807983ba00 EFLAGS: 00010213 RAX: 0000000000000000 RBX: ffff88807983bc00 RCX: 0000000000000000 RDX: ffff88807983bc00 RSI: 0000000000000000 RDI: ffff88807bdd0a80 RBP: ffff88807983baf8 R08: 0000000000000dc0 R09: 000000000000040a R10: 0000000000000000 R11: ffff88807bdd0ae8 R12: 0000000000000000 R13: 0000000000000000 R14: ffff88807bea3100 R15: 0000000000000001 FS: 00007f10db393700(0000) GS:ffff88807dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000080 CR3: 000000007bd0f004 CR4: 00000000003706f0 Call Trace: fib_create_info+0x64d/0xaf7 fib_table_insert+0xf6/0x581 ? __vma_adjust+0x3b6/0x4d4 inet_rtm_newroute+0x56/0x70 rtnetlink_rcv_msg+0x1e3/0x20d ? rtnl_calcit.isra.0+0xb8/0xb8 netlink_rcv_skb+0x5b/0xac netlink_unicast+0xfa/0x17b netlink_sendmsg+0x334/0x353 sock_sendmsg_nosec+0xf/0x3f ____sys_sendmsg+0x1a0/0x1fc ? copy_msghdr_from_user+0x4c/0x61 ___sys_sendmsg+0x63/0x84 ? handle_mm_fault+0xa39/0x11b5 ? sockfd_lookup_light+0x72/0x9a __sys_sendmsg+0x50/0x6e do_syscall_64+0x54/0xbe entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f10dacc0bb7 Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb cd 66 0f 1f 44 00 00 8b 05 9a 4b 2b 00 85 c0 75 2e 48 63 ff 48 63 d2 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 b1 f2 2a 00 f7 d8 64 89 02 48 RSP: 002b:00007ffcbe628bf8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007ffcbe628f80 RCX: 00007f10dacc0bb7 RDX: 0000000000000000 RSI: 00007ffcbe628c60 RDI: 0000000000000003 RBP: 000000005f41099c R08: 0000000000000001 R09: 0000000000000008 R10: 00000000000005e9 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007ffcbe628d70 R15: 0000563a86c6e440 Modules linked in: CR2: 0000000000000080 CC: David Ahern Fixes: 430a049190de ("nexthop: Add support for nexthop groups") Reported-by: syzbot+a61aa19b0c14c8770bd9@syzkaller.appspotmail.com Signed-off-by: Nikolay Aleksandrov Reviewed-by: David Ahern Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/nexthop.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/net/ipv4/nexthop.c +++ b/net/ipv4/nexthop.c @@ -403,7 +403,7 @@ static int nh_check_attr_group(struct ne struct nexthop_grp *nhg; unsigned int i, j; - if (len & (sizeof(struct nexthop_grp) - 1)) { + if (!len || len & (sizeof(struct nexthop_grp) - 1)) { NL_SET_ERR_MSG(extack, "Invalid length for nexthop group attribute"); return -EINVAL; @@ -1105,6 +1105,9 @@ static struct nexthop *nexthop_create_gr struct nexthop *nh; int i; + if (WARN_ON(!num_nh)) + return ERR_PTR(-EINVAL); + nh = nexthop_alloc(); if (!nh) return ERR_PTR(-ENOMEM);