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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 33AE6C43381 for ; Mon, 25 Feb 2019 01:22:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 02F3B20989 for ; Mon, 25 Feb 2019 01:22:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727259AbfBYBWS (ORCPT ); Sun, 24 Feb 2019 20:22:18 -0500 Received: from szxga06-in.huawei.com ([45.249.212.32]:52102 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725991AbfBYBWS (ORCPT ); Sun, 24 Feb 2019 20:22:18 -0500 Received: from DGGEMS404-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 414CB6B527962A6FA409; Mon, 25 Feb 2019 09:22:16 +0800 (CST) Received: from [127.0.0.1] (10.177.21.79) by DGGEMS404-HUB.china.huawei.com (10.3.19.204) with Microsoft SMTP Server id 14.3.408.0; Mon, 25 Feb 2019 09:22:10 +0800 Subject: Re: [RFC PATCH] aio: add check for timeout to aviod invalid value To: Jeff Moyer References: <1550311021-60612-1-git-send-email-tanxiaojun@huawei.com> CC: , , , , , From: Tan Xiaojun Message-ID: <5C734340.7030006@huawei.com> Date: Mon, 25 Feb 2019 09:22:08 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.21.79] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/2/19 4:33, Jeff Moyer wrote: > Tan Xiaojun writes: > >> (When I was testing with syzkaller, I found a lot of ubsan problems. Here >> is one of them. I am not sure if it needs to be fixed and how it will be >> fixed. So I sent this patch to ask your opinion.) >> >> Syzkaller reported a UBSAN bug below, which was mainly caused by a large >> negative number passed to the timeout of the io_getevents system call. >> >> ================================================================================ >> UBSAN: Undefined behaviour in ./include/linux/ktime.h:42:14 >> signed integer overflow: >> -8427032702788048137 * 1000000000 cannot be represented in type 'long long int' >> CPU: 3 PID: 11668 Comm: syz-executor0 Not tainted 4.19.18-514.55.6.9.x86_64+ #1 >> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 >> Call Trace: >> __dump_stack lib/dump_stack.c:77 [inline] >> dump_stack+0xca/0x13e lib/dump_stack.c:113 >> ubsan_epilogue+0xe/0x81 lib/ubsan.c:159 >> handle_overflow+0x193/0x1e2 lib/ubsan.c:190 >> ktime_set include/linux/ktime.h:42 [inline] >> timespec64_to_ktime include/linux/ktime.h:78 [inline] >> do_io_getevents+0x307/0x390 fs/aio.c:2043 >> __do_sys_io_getevents fs/aio.c:2080 [inline] >> __se_sys_io_getevents fs/aio.c:2068 [inline] >> __x64_sys_io_getevents+0x163/0x250 fs/aio.c:2068 >> do_syscall_64+0xc8/0x580 arch/x86/entry/common.c:290 >> entry_SYSCALL_64_after_hwframe+0x49/0xbe >> RIP: 0033:0x462589 >> Code: f7 d8 64 89 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 >> RSP: 002b:00007fde9b04ec58 EFLAGS: 00000246 ORIG_RAX: 00000000000000d0 >> RAX: ffffffffffffffda RBX: 000000000072bf00 RCX: 0000000000462589 >> RDX: 0000000000000006 RSI: 0000000000000000 RDI: 0000000000000000 >> RBP: 0000000000000005 R08: 0000000020000100 R09: 0000000000000000 >> R10: 0000000020000040 R11: 0000000000000246 R12: 00007fde9b04f6bc >> R13: 00000000004bd1f0 R14: 00000000006f6b60 R15: 00000000ffffffff >> ================================================================================ >> bond0 (unregistering): Released all slaves >> >> The timeout described in "man io_getevents" does not say whether it >> can be negative or not, but as a waiting time, a negative number has >> no meaning. So I add check to avoid this case. > > It's embarrassing that this bug is still present. See, for example, > this discussion, started in 2015: > https://lore.kernel.org/lkml/CACT4Y+bBxVYLQ6LtOKrKtnLthqLHcw-BMp3aqP3mjdAvr9FULQ@mail.gmail.com/ > > I could swear it was brought up again since then, but I can't find > records of that. > Yes. I will add this, thank you. >> Signed-off-by: Tan Xiaojun >> --- >> fs/aio.c | 7 ++++++- >> 1 file changed, 6 insertions(+), 1 deletion(-) >> >> diff --git a/fs/aio.c b/fs/aio.c >> index aaaaf4d..28e0fa6 100644 >> --- a/fs/aio.c >> +++ b/fs/aio.c >> @@ -2078,10 +2078,15 @@ static long do_io_getevents(aio_context_t ctx_id, >> struct io_event __user *events, >> struct timespec64 *ts) >> { >> - ktime_t until = ts ? timespec64_to_ktime(*ts) : KTIME_MAX; >> + ktime_t until; >> struct kioctx *ioctx = lookup_ioctx(ctx_id); >> long ret = -EINVAL; >> >> + if (ts && !timespec64_valid(ts)) >> + return -EINVAL; >> + >> + until = ts ? timespec64_to_ktime(*ts) : KTIME_MAX; >> + >> if (likely(ioctx)) { >> if (likely(min_nr <= nr && min_nr >= 0)) >> ret = read_events(ioctx, min_nr, nr, events, until); > > Looks good to me. Thanks for fixing this. > > Reviewed-by: Jeff Moyer Thank you for your reply, I went out for a trip last week. I will send it officially immediately. Xiaojun. > > . >