From patchwork Mon Apr 1 20:59:54 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Michael Roth X-Patchwork-Id: 1073397 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.vnet.ibm.com Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 44Y6CN2BRfz9sSG for ; Tue, 2 Apr 2019 09:17:20 +1100 (AEDT) Received: from localhost ([127.0.0.1]:57783 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hB5F0-00052P-5e for incoming@patchwork.ozlabs.org; Mon, 01 Apr 2019 18:17:18 -0400 Received: from eggs.gnu.org ([209.51.188.92]:42930) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hB478-0003ii-II for qemu-devel@nongnu.org; Mon, 01 Apr 2019 17:05:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hB476-0004ym-Ad for qemu-devel@nongnu.org; Mon, 01 Apr 2019 17:05:06 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:59922 helo=mx0a-001b2d01.pphosted.com) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hB476-0004pz-4S for qemu-devel@nongnu.org; Mon, 01 Apr 2019 17:05:04 -0400 Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x31L4i17163580 for ; Mon, 1 Apr 2019 17:04:53 -0400 Received: from e34.co.us.ibm.com (e34.co.us.ibm.com [32.97.110.152]) by mx0b-001b2d01.pphosted.com with ESMTP id 2rksx78v4w-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 01 Apr 2019 17:04:48 -0400 Received: from localhost by e34.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Mon, 1 Apr 2019 22:02:59 +0100 Received: from b03ledav005.gho.boulder.ibm.com (b03ledav005.gho.boulder.ibm.com [9.17.130.236]) by b03cxnp08027.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x31L2wGU52625408 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 1 Apr 2019 21:02:58 GMT Received: from b03ledav005.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C9059BE04F; Mon, 1 Apr 2019 21:02:58 +0000 (GMT) Received: from b03ledav005.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8FB55BE054; Mon, 1 Apr 2019 21:02:58 +0000 (GMT) Received: from localhost (unknown [9.80.94.43]) by b03ledav005.gho.boulder.ibm.com (Postfix) with ESMTP; Mon, 1 Apr 2019 21:02:58 +0000 (GMT) From: Michael Roth To: qemu-devel@nongnu.org Date: Mon, 1 Apr 2019 15:59:54 -0500 X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190401210011.16009-1-mdroth@linux.vnet.ibm.com> References: <20190401210011.16009-1-mdroth@linux.vnet.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 x-cbid: 19040121-0016-0000-0000-0000099B1DFB X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00010857; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000283; SDB=6.01182941; UDB=6.00619269; IPR=6.00963684; MB=3.00026249; MTD=3.00000008; XFM=3.00000015; UTC=2019-04-01 21:03:01 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19040121-0017-0000-0000-000042A9B24F Message-Id: <20190401210011.16009-81-mdroth@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-04-01_06:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904010136 X-MIME-Autoconverted: from 8bit to quoted-printable by mx0b-001b2d01.pphosted.com id x31L4i17163580 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [generic] X-Received-From: 148.163.158.5 Subject: [Qemu-devel] [PATCH 80/97] linux-user: make pwrite64/pread64(fd, NULL, 0, offset) return 0 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , qemu-stable@nongnu.org, Laurent Vivier Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" From: Peter Maydell Linux returns success if pwrite64() or pread64() are called with a zero length NULL buffer, but QEMU was returning -TARGET_EFAULT. This is the same bug that we fixed in commit 58cfa6c2e6eb51b23cc9 for the write syscall, and long before that in 38d840e6790c29f59 for the read syscall. Fixes: https://bugs.launchpad.net/qemu/+bug/1810433 Signed-off-by: Peter Maydell Reviewed-by: Laurent Vivier Reviewed-by: Philippe Mathieu-Daudé Message-Id: <20190108184900.9654-1-peter.maydell@linaro.org> Signed-off-by: Laurent Vivier (cherry picked from commit 2bd3f8998e1e7dcd9afc29fab252fb9936f9e956) *drop functional dep. on 2852aafd9d Signed-off-by: Michael Roth --- linux-user/syscall.c | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 1477509cf2..0859739e9d 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -10910,8 +10910,15 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, arg4 = arg5; arg5 = arg6; } - if (!(p = lock_user(VERIFY_WRITE, arg2, arg3, 0))) - goto efault; + if (arg2 == 0 && arg3 == 0) { + /* Special-case NULL buffer and zero length, which should succeed */ + p = 0; + } else { + p = lock_user(VERIFY_WRITE, arg2, arg3, 0); + if (!p) { + goto efault; + } + } ret = get_errno(pread64(arg1, p, arg3, target_offset64(arg4, arg5))); unlock_user(p, arg2, ret); break; @@ -10920,8 +10927,15 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, arg4 = arg5; arg5 = arg6; } - if (!(p = lock_user(VERIFY_READ, arg2, arg3, 1))) - goto efault; + if (arg2 == 0 && arg3 == 0) { + /* Special-case NULL buffer and zero length, which should succeed */ + p = 0; + } else { + p = lock_user(VERIFY_READ, arg2, arg3, 1); + if (!p) { + goto efault; + } + } ret = get_errno(pwrite64(arg1, p, arg3, target_offset64(arg4, arg5))); unlock_user(p, arg2, 0); break;