From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755809AbcETNDg (ORCPT ); Fri, 20 May 2016 09:03:36 -0400 Received: from e06smtp05.uk.ibm.com ([195.75.94.101]:49348 "EHLO e06smtp05.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755739AbcETNDf (ORCPT ); Fri, 20 May 2016 09:03:35 -0400 X-IBM-Helo: d06dlp01.portsmouth.uk.ibm.com X-IBM-MailFrom: heiko.carstens@de.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org;linux-s390@vger.kernel.org Date: Fri, 20 May 2016 15:03:25 +0200 From: Heiko Carstens To: Muhammad Falak R Wani Cc: Martin Schwidefsky , Jan Kara , "open list:S390" , open list Subject: Re: [PATCH] ks390/keyboard: use memdup_user(). Message-ID: <20160520130325.GE3461@osiris> References: <1463746939-23892-1-git-send-email-falakreyaz@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1463746939-23892-1-git-send-email-falakreyaz@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16052013-0021-0000-0000-00001C048826 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 20, 2016 at 05:52:16PM +0530, Muhammad Falak R Wani wrote: > Use memdup_user to duplicate a memory region from user-space to > kernel-space, instead of open coding using kmalloc & copy_from_user. > > Signed-off-by: Muhammad Falak R Wani > --- > drivers/s390/char/keyboard.c | 10 +++------- > 1 file changed, 3 insertions(+), 7 deletions(-) > > diff --git a/drivers/s390/char/keyboard.c b/drivers/s390/char/keyboard.c > index ef04a9f..2955983 100644 > --- a/drivers/s390/char/keyboard.c > +++ b/drivers/s390/char/keyboard.c > @@ -438,13 +438,9 @@ do_kdgkb_ioctl(struct kbd_data *kbd, struct kbsentry __user *u_kbs, > return -EFAULT; > if (len > sizeof(u_kbs->kb_string)) > return -EINVAL; > - p = kmalloc(len, GFP_KERNEL); > - if (!p) > - return -ENOMEM; > - if (copy_from_user(p, u_kbs->kb_string, len)) { > - kfree(p); > - return -EFAULT; > - } > + p = memdup_user(u_kbs->kb_string, len); > + if (IS_ERR(p)) > + return PTR_ERR(p); > /* > * Make sure the string is terminated by 0. User could have > * modified it between us running strnlen_user() and copying it. Hi Muhammad, thanks for this patch. However could you change this to use memdup_user_nul() instead, so we can get rid of even more code?