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=-15.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 AD0C2C4708F for ; Mon, 31 May 2021 06:10:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 84986610A6 for ; Mon, 31 May 2021 06:10:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230192AbhEaGLh (ORCPT ); Mon, 31 May 2021 02:11:37 -0400 Received: from szxga08-in.huawei.com ([45.249.212.255]:3298 "EHLO szxga08-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230006AbhEaGL0 (ORCPT ); Mon, 31 May 2021 02:11:26 -0400 Received: from dggemv704-chm.china.huawei.com (unknown [172.30.72.56]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4FtlBS3Rggz1BGpV; Mon, 31 May 2021 14:05:04 +0800 (CST) Received: from dggpeml500017.china.huawei.com (7.185.36.243) by dggemv704-chm.china.huawei.com (10.3.19.47) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Mon, 31 May 2021 14:09:41 +0800 Received: from [10.174.178.174] (10.174.178.174) by dggpeml500017.china.huawei.com (7.185.36.243) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Mon, 31 May 2021 14:09:40 +0800 Subject: Re: [PATCH -next v2] cifsd: check return value of ksmbd_vfs_getcasexattr() correctly To: Hyunchul Lee CC: LKML , linux-cifsd-devel , linux-cifs , Namjae Jeon , "Sergey Senozhatsky" , Steve French References: <20210531030550.1708816-1-yangyingliang@huawei.com> From: Yang Yingliang Message-ID: <0d4edde6-f8e8-5100-5c06-54ff2e0a7378@huawei.com> Date: Mon, 31 May 2021 14:09:40 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Originating-IP: [10.174.178.174] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpeml500017.china.huawei.com (7.185.36.243) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/5/31 13:38, Hyunchul Lee wrote: > 2021년 5월 31일 (월) 오후 12:01, Yang Yingliang 님이 작성: >> If ksmbd_vfs_getcasexattr() returns -ENOMEM, stream_buf is NULL, >> it will cause null-ptr-deref when using it to copy memory. So we >> need check the return value of ksmbd_vfs_getcasexattr() by comparing >> with 0. >> >> Fixes: f44158485826 ("cifsd: add file operations") >> Signed-off-by: Yang Yingliang >> --- >> v2: >> Handle the case ksmbd_vfs_getcasexattr() returns 0. >> --- >> fs/cifsd/vfs.c | 10 ++++------ >> 1 file changed, 4 insertions(+), 6 deletions(-) >> >> diff --git a/fs/cifsd/vfs.c b/fs/cifsd/vfs.c >> index 97d5584ec870..2a9cc0bc7726 100644 >> --- a/fs/cifsd/vfs.c >> +++ b/fs/cifsd/vfs.c >> @@ -274,7 +274,6 @@ static int ksmbd_vfs_stream_read(struct ksmbd_file *fp, char *buf, loff_t *pos, >> { >> ssize_t v_len; >> char *stream_buf = NULL; >> - int err; >> >> ksmbd_debug(VFS, "read stream data pos : %llu, count : %zd\n", >> *pos, count); >> @@ -283,10 +282,9 @@ static int ksmbd_vfs_stream_read(struct ksmbd_file *fp, char *buf, loff_t *pos, >> fp->stream.name, >> fp->stream.size, >> &stream_buf); >> - if (v_len == -ENOENT) { >> + if ((int)v_len <= 0) { >> ksmbd_err("not found stream in xattr : %zd\n", v_len); >> - err = -ENOENT; >> - return err; >> + return v_len == 0 ? -ENOENT : (int)v_len; > How about making ksmbd_vfs_getcasexattr return -ENONENT instead of > returning 0 to > remove duplicate error handling code? Yes, I think it's ok, I will send a v3 later. Thanks, Yang > > Thanks, > Hyunchul > >> } >> >> memcpy(buf, &stream_buf[*pos], count); >> @@ -415,9 +413,9 @@ static int ksmbd_vfs_stream_write(struct ksmbd_file *fp, char *buf, loff_t *pos, >> fp->stream.name, >> fp->stream.size, >> &stream_buf); >> - if (v_len == -ENOENT) { >> + if ((int)v_len <= 0) { >> ksmbd_err("not found stream in xattr : %zd\n", v_len); >> - err = -ENOENT; >> + err = v_len == 0 ? -ENOENT : (int)v_len; >> goto out; >> } >> >> -- >> 2.25.1 >> > .