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 F0AD3C76186 for ; Mon, 29 Jul 2019 19:38:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BC9B6206DD for ; Mon, 29 Jul 2019 19:38:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564429121; bh=HRmdymFz9CoKWHbTLjLYlSb8GYeHY4UE37+eJqbgQPE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=K4FkxATcBpgczonmnoGciCyyUlG3dPuV7CtkgSA1kfJ+NUoQSQ9my6VWJ3s0Fbhm+ 1UUmVgcYMAXjJRrL2tcCS6MZ/UcNUO7n9zHJChXq0wbl7kIjCRP2duTWFUyhLVw9F7 KA5723vGU2J2sVK9O1ACaBiazr7TBBcfLXw6cvYQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388897AbfG2Til (ORCPT ); Mon, 29 Jul 2019 15:38:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:53524 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388559AbfG2Tid (ORCPT ); Mon, 29 Jul 2019 15:38:33 -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 BE5A720C01; Mon, 29 Jul 2019 19:38:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564429112; bh=HRmdymFz9CoKWHbTLjLYlSb8GYeHY4UE37+eJqbgQPE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QYrRAU1y8pOxOOlIr+Vu6NFMKm20CjQDPOOLlMtJ4+b+tT6A7kHsCpHn76u6Dqk9J nNTdH8R4dMQRjmGCfK33ak2Bb2nnuYlwGMTEKAooSCvAYSP7HV0W8aOIOWQZfrCN6U B/bygsyfHK5lXzEKj1wfp5uOdLFSNJb5UQjk6QMU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kefeng Wang , Zhang HongJun , Arnd Bergmann Subject: [PATCH 4.14 288/293] hpet: Fix division by zero in hpet_time_div() Date: Mon, 29 Jul 2019 21:22:59 +0200 Message-Id: <20190729190846.309781280@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190729190820.321094988@linuxfoundation.org> References: <20190729190820.321094988@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: Kefeng Wang commit 0c7d37f4d9b8446956e97b7c5e61173cdb7c8522 upstream. The base value in do_div() called by hpet_time_div() is truncated from unsigned long to uint32_t, resulting in a divide-by-zero exception. UBSAN: Undefined behaviour in ../drivers/char/hpet.c:572:2 division by zero CPU: 1 PID: 23682 Comm: syz-executor.3 Not tainted 4.4.184.x86_64+ #4 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 0000000000000000 b573382df1853d00 ffff8800a3287b98 ffffffff81ad7561 ffff8800a3287c00 ffffffff838b35b0 ffffffff838b3860 ffff8800a3287c20 0000000000000000 ffff8800a3287bb0 ffffffff81b8f25e ffffffff838b35a0 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [] ubsan_epilogue+0x12/0x8d lib/ubsan.c:166 [] __ubsan_handle_divrem_overflow+0x282/0x2c8 lib/ubsan.c:262 [] hpet_time_div drivers/char/hpet.c:572 [inline] [] hpet_ioctl_common drivers/char/hpet.c:663 [inline] [] hpet_ioctl_common.cold+0xa8/0xad drivers/char/hpet.c:577 [] hpet_ioctl+0xc6/0x180 drivers/char/hpet.c:676 [] vfs_ioctl fs/ioctl.c:43 [inline] [] file_ioctl fs/ioctl.c:470 [inline] [] do_vfs_ioctl+0x6e0/0xf70 fs/ioctl.c:605 [] SYSC_ioctl fs/ioctl.c:622 [inline] [] SyS_ioctl+0x94/0xc0 fs/ioctl.c:613 [] tracesys_phase2+0x90/0x95 The main C reproducer autogenerated by syzkaller, syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0); memcpy((void*)0x20000100, "/dev/hpet\000", 10); syscall(__NR_openat, 0xffffffffffffff9c, 0x20000100, 0, 0); syscall(__NR_ioctl, r[0], 0x40086806, 0x40000000000000); Fix it by using div64_ul(). Signed-off-by: Kefeng Wang Signed-off-by: Zhang HongJun Cc: stable Reviewed-by: Arnd Bergmann Link: https://lore.kernel.org/r/20190711132757.130092-1-wangkefeng.wang@huawei.com Signed-off-by: Greg Kroah-Hartman --- drivers/char/hpet.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/drivers/char/hpet.c +++ b/drivers/char/hpet.c @@ -570,8 +570,7 @@ static inline unsigned long hpet_time_di unsigned long long m; m = hpets->hp_tick_freq + (dis >> 1); - do_div(m, dis); - return (unsigned long)m; + return div64_ul(m, dis); } static int