From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:54254 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966370AbeEXJmh (ORCPT ); Thu, 24 May 2018 05:42:37 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, zhongjiang , Oleg Nesterov , David Rientjes , "Aneesh Kumar K.V" , "Kirill A. Shutemov" , Xishi Qiu , Andrew Morton , Linus Torvalds Subject: [PATCH 3.18 22/45] kernel/exit.c: avoid undefined behaviour when calling wait4() Date: Thu, 24 May 2018 11:38:30 +0200 Message-Id: <20180524093123.476616286@linuxfoundation.org> In-Reply-To: <20180524093120.599252450@linuxfoundation.org> References: <20180524093120.599252450@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: zhongjiang commit dd83c161fbcc5d8be637ab159c0de015cbff5ba4 upstream. wait4(-2147483648, 0x20, 0, 0xdd0000) triggers: UBSAN: Undefined behaviour in kernel/exit.c:1651:9 The related calltrace is as follows: negation of -2147483648 cannot be represented in type 'int': CPU: 9 PID: 16482 Comm: zj Tainted: G B ---- ------- 3.10.0-327.53.58.71.x86_64+ #66 Hardware name: Huawei Technologies Co., Ltd. Tecal RH2285 /BC11BTSA , BIOS CTSAV036 04/27/2011 Call Trace: dump_stack+0x19/0x1b ubsan_epilogue+0xd/0x50 __ubsan_handle_negate_overflow+0x109/0x14e SyS_wait4+0x1cb/0x1e0 system_call_fastpath+0x16/0x1b Exclude the overflow to avoid the UBSAN warning. Link: http://lkml.kernel.org/r/1497264618-20212-1-git-send-email-zhongjiang@huawei.com Signed-off-by: zhongjiang Cc: Oleg Nesterov Cc: David Rientjes Cc: Aneesh Kumar K.V Cc: Kirill A. Shutemov Cc: Xishi Qiu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- kernel/exit.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1620,6 +1620,10 @@ SYSCALL_DEFINE4(wait4, pid_t, upid, int __WNOTHREAD|__WCLONE|__WALL)) return -EINVAL; + /* -INT_MIN is not defined */ + if (upid == INT_MIN) + return -ESRCH; + if (upid == -1) type = PIDTYPE_MAX; else if (upid < 0) {