From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755504Ab0GaIj5 (ORCPT ); Sat, 31 Jul 2010 04:39:57 -0400 Received: from mx01.sz.bfs.de ([194.94.69.103]:44813 "EHLO mx01.sz.bfs.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753446Ab0GaIjz (ORCPT ); Sat, 31 Jul 2010 04:39:55 -0400 Message-ID: <4C53E157.8080102@bfs.de> Date: Sat, 31 Jul 2010 10:39:51 +0200 From: walter harms Reply-To: wharms@bfs.de User-Agent: Thunderbird 2.0.0.24 (X11/20100302) MIME-Version: 1.0 To: Willy Tarreau CC: Kulikov Vasiliy , kernel-janitors@vger.kernel.org, Greg Kroah-Hartman , Peter Huewe , Andy Shevchenko , Julia Lawall , devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 5/9] staging: panel: check put_user() return value References: <1280488123-20859-1-git-send-email-segooon@gmail.com> <20100730211544.GH19782@1wt.eu> In-Reply-To: <20100730211544.GH19782@1wt.eu> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Willy Tarreau schrieb: > On Fri, Jul 30, 2010 at 03:08:42PM +0400, Kulikov Vasiliy wrote: >> diff --git a/drivers/staging/panel/panel.c b/drivers/staging/panel/panel.c >> index f58da32..57f4946 100644 >> --- a/drivers/staging/panel/panel.c >> +++ b/drivers/staging/panel/panel.c >> @@ -1589,25 +1589,30 @@ void lcd_init(void) >> static ssize_t keypad_read(struct file *file, >> char *buf, size_t count, loff_t *ppos) >> { >> - >> + int buflen = keypad_buflen; >> unsigned i = *ppos; >> char *tmp = buf; >> + int start = keypad_start; >> >> - if (keypad_buflen == 0) { >> + if (buflen == 0) { >> if (file->f_flags & O_NONBLOCK) >> return -EAGAIN; >> >> interruptible_sleep_on(&keypad_read_wait); >> if (signal_pending(current)) >> return -EINTR; >> + buflen = keypad_buflen; >> } > > Not sure what the intent was here, I think you're re-adjusting > the buffer's length in case something else was read. But then > I don't understand why buflen it not simply assigned after the > if() block. > > The rest below looks fine otherwise. > >> >> - for (; count-- > 0 && (keypad_buflen > 0); >> - ++i, ++tmp, --keypad_buflen) { >> - put_user(keypad_buffer[keypad_start], tmp); >> - keypad_start = (keypad_start + 1) % KEYPAD_BUFFER; >> + for (; count-- > 0 && (buflen > 0); >> + ++i, ++tmp, --buflen) { >> + if (put_user(keypad_buffer[start], tmp)) >> + return -EFAULT; >> + start = (start + 1) % KEYPAD_BUFFER; >> } >> *ppos = i; >> + keypad_buflen = buflen; >> + keypad_start = start; >> >> return tmp - buf; >> } > > IMHO opinion the for() construct breaks the rule of "no surprise please". perhaps a while() would improve readability. just my two cents, re, wh