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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, 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 C0923C6379F for ; Tue, 17 Nov 2020 13:18:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7B39C2225B for ; Tue, 17 Nov 2020 13:18:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="abl63Hpj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730588AbgKQNRp (ORCPT ); Tue, 17 Nov 2020 08:17:45 -0500 Received: from mail.kernel.org ([198.145.29.99]:49716 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730557AbgKQNR1 (ORCPT ); Tue, 17 Nov 2020 08:17:27 -0500 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 EF738206D5; Tue, 17 Nov 2020 13:17:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1605619046; bh=QgDgQ4frAwnB+dR6pI1lZLkBY0lciBNMnTt8BjZaNog=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=abl63HpjTdlQwx04jSe/YLSzyrHUJG5hlqt8MRSjgPmIvRIc9lkY05uCb8wkQKn24 q1FhnW9725Qq89brzzmEfsh4Ekn2fhUWf3VQE2U/fQTeJtMiLJqTqm+sASV1ThHgPM 3gHMOMShS0DGKBWNBNjSzba3h4Nv/MDLJPUHakmg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Zeng Tao , Thomas Gleixner , Arnd Bergmann , Sasha Levin Subject: [PATCH 4.19 002/101] time: Prevent undefined behaviour in timespec64_to_ns() Date: Tue, 17 Nov 2020 14:04:29 +0100 Message-Id: <20201117122113.240871219@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201117122113.128215851@linuxfoundation.org> References: <20201117122113.128215851@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Zeng Tao [ Upstream commit cb47755725da7b90fecbb2aa82ac3b24a7adb89b ] UBSAN reports: Undefined behaviour in ./include/linux/time64.h:127:27 signed integer overflow: 17179869187 * 1000000000 cannot be represented in type 'long long int' Call Trace: timespec64_to_ns include/linux/time64.h:127 [inline] set_cpu_itimer+0x65c/0x880 kernel/time/itimer.c:180 do_setitimer+0x8e/0x740 kernel/time/itimer.c:245 __x64_sys_setitimer+0x14c/0x2c0 kernel/time/itimer.c:336 do_syscall_64+0xa1/0x540 arch/x86/entry/common.c:295 Commit bd40a175769d ("y2038: itimer: change implementation to timespec64") replaced the original conversion which handled time clamping correctly with timespec64_to_ns() which has no overflow protection. Fix it in timespec64_to_ns() as this is not necessarily limited to the usage in itimers. [ tglx: Added comment and adjusted the fixes tag ] Fixes: 361a3bf00582 ("time64: Add time64.h header and define struct timespec64") Signed-off-by: Zeng Tao Signed-off-by: Thomas Gleixner Reviewed-by: Arnd Bergmann Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/1598952616-6416-1-git-send-email-prime.zeng@hisilicon.com Signed-off-by: Sasha Levin --- include/linux/time64.h | 4 ++++ kernel/time/itimer.c | 4 ---- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/include/linux/time64.h b/include/linux/time64.h index 4a45aea0f96e9..8dbdf6cae3e8b 100644 --- a/include/linux/time64.h +++ b/include/linux/time64.h @@ -138,6 +138,10 @@ static inline bool timespec64_valid_settod(const struct timespec64 *ts) */ static inline s64 timespec64_to_ns(const struct timespec64 *ts) { + /* Prevent multiplication overflow */ + if ((unsigned long long)ts->tv_sec >= KTIME_SEC_MAX) + return KTIME_MAX; + return ((s64) ts->tv_sec * NSEC_PER_SEC) + ts->tv_nsec; } diff --git a/kernel/time/itimer.c b/kernel/time/itimer.c index 9a65713c83093..2e2b335ef1018 100644 --- a/kernel/time/itimer.c +++ b/kernel/time/itimer.c @@ -154,10 +154,6 @@ static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, u64 oval, nval, ointerval, ninterval; struct cpu_itimer *it = &tsk->signal->it[clock_id]; - /* - * Use the to_ktime conversion because that clamps the maximum - * value to KTIME_MAX and avoid multiplication overflows. - */ nval = ktime_to_ns(timeval_to_ktime(value->it_value)); ninterval = ktime_to_ns(timeval_to_ktime(value->it_interval)); -- 2.27.0