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[23.128.96.18]) by mx.google.com with ESMTP id i4si1336915edt.77.2020.07.27.11.56.05; Mon, 27 Jul 2020 11:56:27 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=QVgmXgw8; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729597AbgG0RNn (ORCPT + 99 others); Mon, 27 Jul 2020 13:13:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:47124 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728939AbgG0RNn (ORCPT ); Mon, 27 Jul 2020 13:13:43 -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 79D77206E7; Mon, 27 Jul 2020 17:13:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595870023; bh=3eRtGhVMR6oQbug4MP6QIehIPYVlI3wFYiSzkVQnCWY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=QVgmXgw8Ox+DIaTIQpkzrpEjLpQadO/dvxoyVd6gZpA3uWvZ9xjQDH36f0L+9mL81 6rEt3OY35uBvdRZLjqVVYT2kz3ulZf9CGaGNR53LjAMmxDclz2w95GlIu/FKNO5i3t DqKvRdvdKEucRpBYzKsGcBnq1tmI4MlQtHQsJows= Date: Mon, 27 Jul 2020 16:24:16 +0200 From: Greg KH To: B K Karthik Cc: Jon Maloy , Ying Xue , "David S. Miller" , Jakub Kicinski , Linux Kernel Network Developers , tipc-discussion@lists.sourceforge.net, LKML , Shuah Khan , linux-kernel-mentees@lists.linuxfoundation.org Subject: Re: [PATCH] net: tipc: fix general protection fault in tipc_conn_delete_sub Message-ID: <20200727142416.GA186956@kroah.com> References: <20200727131057.7a3of3hhsld4ng5t@pesu.pes.edu> <20200727132256.GA3933866@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 27, 2020 at 07:46:05PM +0530, B K Karthik wrote: > On Mon, Jul 27, 2020 at 6:53 PM Greg KH wrote: > > > > On Mon, Jul 27, 2020 at 06:40:57PM +0530, B K Karthik wrote: > > > fix a general protection fault in tipc_conn_delete_sub > > > by checking for the existance of con->server. > > > prevent a null-ptr-deref by returning -EINVAL when > > > con->server is NULL > > > > > > general protection fault, probably for non-canonical address 0xdffffc0000000014: 0000 [#1] PREEMPT SMP KASAN > > > KASAN: null-ptr-deref in range [0x00000000000000a0-0x00000000000000a7] > > > CPU: 1 PID: 113 Comm: kworker/u4:3 Not tainted 5.6.0-syzkaller #0 > > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > > > Workqueue: tipc_send tipc_conn_send_work > > > RIP: 0010:tipc_conn_delete_sub+0x54/0x440 net/tipc/topsrv.c:231 > > > Code: 48 c1 ea 03 80 3c 02 00 0f 85 f0 03 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 6b 18 48 8d bd a0 00 00 00 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 c0 03 00 00 48 c7 c0 34 0b 8a 8a 4c 8b a5 a0 00 > > > RSP: 0018:ffffc900012d7b58 EFLAGS: 00010206 > > > RAX: dffffc0000000000 RBX: ffff8880a8269c00 RCX: ffffffff8789ca01 > > > RDX: 0000000000000014 RSI: ffffffff8789a059 RDI: 00000000000000a0 > > > RBP: 0000000000000000 R08: ffff8880a8d88380 R09: fffffbfff18577a8 > > > R10: fffffbfff18577a7 R11: ffffffff8c2bbd3f R12: dffffc0000000000 > > > R13: ffff888093d35a18 R14: ffff8880a8269c00 R15: ffff888093d35a00 > > > FS: 0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 > > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > > CR2: 000000000076c000 CR3: 000000009441d000 CR4: 00000000001406e0 > > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > > Call Trace: > > > tipc_conn_send_to_sock+0x380/0x560 net/tipc/topsrv.c:266 > > > tipc_conn_send_work+0x6f/0x90 net/tipc/topsrv.c:304 > > > process_one_work+0x965/0x16a0 kernel/workqueue.c:2266 > > > worker_thread+0x96/0xe20 kernel/workqueue.c:2412 > > > kthread+0x388/0x470 kernel/kthread.c:268 > > > ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 > > > Modules linked in: > > > ---[ end trace 2c161a84be832606 ]--- > > > RIP: 0010:tipc_conn_delete_sub+0x54/0x440 net/tipc/topsrv.c:231 > > > Code: 48 c1 ea 03 80 3c 02 00 0f 85 f0 03 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 6b 18 48 8d bd a0 00 00 00 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 c0 03 00 00 48 c7 c0 34 0b 8a 8a 4c 8b a5 a0 00 > > > RSP: 0018:ffffc900012d7b58 EFLAGS: 00010206 > > > RAX: dffffc0000000000 RBX: ffff8880a8269c00 RCX: ffffffff8789ca01 > > > RDX: 0000000000000014 RSI: ffffffff8789a059 RDI: 00000000000000a0 > > > RBP: 0000000000000000 R08: ffff8880a8d88380 R09: fffffbfff18577a8 > > > R10: fffffbfff18577a7 R11: ffffffff8c2bbd3f R12: dffffc0000000000 > > > R13: ffff888093d35a18 R14: ffff8880a8269c00 R15: ffff888093d35a00 > > > FS: 0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 > > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > > CR2: 0000000020800000 CR3: 0000000091b8e000 CR4: 00000000001406e0 > > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > > > > > Reported-and-tested-by: syzbot+55a38037455d0351efd3@syzkaller.appspotmail.com > > > Signed-off-by: B K Karthik > > > --- > > > net/tipc/topsrv.c | 3 +++ > > > 1 file changed, 3 insertions(+) > > > > > > diff --git a/net/tipc/topsrv.c b/net/tipc/topsrv.c > > > index 1489cfb941d8..6c8d0c6bb112 100644 > > > --- a/net/tipc/topsrv.c > > > +++ b/net/tipc/topsrv.c > > > @@ -255,6 +255,9 @@ static void tipc_conn_send_to_sock(struct tipc_conn *con) > > > int count = 0; > > > int ret; > > > > > > + if (!con->server) > > > + return -EINVAL; > > > > What is wrong with looking at the srv local variable instead? > > > > And how is server getting set to NULL and this function still being > > called? > > tipc_conn_send_work makes a call to connected() which just returns con > && test_bit(CF_CONNECTED, &con->flags) > maybe we can add this check to the implementation of connection() if > you agree, but I found this solution to be fairly simpler because I'm > not sure where else connected() is being used, and I did not want to > introduce redundant function calls. That's not what I asked here at all. greg k-h