From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52320) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WAGw8-0006BM-4X for qemu-devel@nongnu.org; Mon, 03 Feb 2014 05:39:40 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WAGvz-000807-3o for qemu-devel@nongnu.org; Mon, 03 Feb 2014 05:39:32 -0500 Received: from mail-pa0-x233.google.com ([2607:f8b0:400e:c03::233]:51616) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WAGvy-000801-S1 for qemu-devel@nongnu.org; Mon, 03 Feb 2014 05:39:23 -0500 Received: by mail-pa0-f51.google.com with SMTP id ld10so6936582pab.38 for ; Mon, 03 Feb 2014 02:39:21 -0800 (PST) Message-ID: <52EF71DC.3000309@gmail.com> Date: Mon, 03 Feb 2014 18:39:24 +0800 From: Chen Gang MIME-Version: 1.0 References: <52EF68CA.9060604@gmail.com> <20140203103429.GB10408@redhat.com> In-Reply-To: <20140203103429.GB10408@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] hw/9pfs/virtio-9p-local.c: use snprintf() instead of sprintf() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Daniel P. Berrange" Cc: aneesh.kumar@linux.vnet.ibm.com, aliguori@amazon.com, QEMU Developers On 02/03/2014 06:34 PM, Daniel P. Berrange wrote: > On Mon, Feb 03, 2014 at 06:00:42PM +0800, Chen Gang wrote: >> We can not assume "'path' + 'ctx->fs_root'" must be less than MAX_PATH, >> so need use snprintf() instead of sprintf(). >> >> And also recommend to use ARRAY_SIZE instead of hard code macro for an >> array size in snprintf(). > > In the event that there is overflow this will cause the data to be > truncated, potentially causing QEMU to access the wrong file on the > host. Both snprintf and sprintf are really bad because of their > use of fixed buffers. Better to change it to g_strdup_printf which > dynamically allocates buffers. > That sounds reasonable to me, I will send patch v2 for it. Thanks. -- Chen Gang Open, share and attitude like air, water and life which God blessed