Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933924Ab0FCKmM (ORCPT ); Thu, 3 Jun 2010 06:42:12 -0400 Received: from casper.infradead.org ([85.118.1.10]:46939 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933762Ab0FCKmH convert rfc822-to-8bit (ORCPT ); Thu, 3 Jun 2010 06:42:07 -0400 Subject: Re: [patch v2] fcntl: return -EFAULT if copy_to_user fails From: Peter Zijlstra To: Dan Carpenter Cc: Takuya Yoshikawa , Matthew Wilcox , Alexander Viro , Andrew Morton , Oleg Nesterov , Jens Axboe , Greg Kroah-Hartman , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20100603103542.GV5483@bicker> References: <20100603100402.GR5483@bicker> <4C07826A.6060302@oss.ntt.co.jp> <20100603103542.GV5483@bicker> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Thu, 03 Jun 2010 12:42:14 +0200 Message-ID: <1275561734.27810.35399.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1295 Lines: 44 On Thu, 2010-06-03 at 12:35 +0200, Dan Carpenter wrote: > copy_to_user() returns the number of bytes remaining, but we want to > return -EFAULT. > ret = fcntl(fd, F_SETOWN_EX, NULL); > With the original code ret would be 8 here. > > V2: Takuya Yoshikawa pointed out a similar issue in f_getown_ex() > > Signed-off-by: Dan Carpenter Acked-by: Peter Zijlstra > diff --git a/fs/fcntl.c b/fs/fcntl.c > index f74d270..51e11bf 100644 > --- a/fs/fcntl.c > +++ b/fs/fcntl.c > @@ -274,7 +274,7 @@ static int f_setown_ex(struct file *filp, unsigned long arg) > > ret = copy_from_user(&owner, owner_p, sizeof(owner)); > if (ret) > - return ret; > + return -EFAULT; > > switch (owner.type) { > case F_OWNER_TID: > @@ -332,8 +332,11 @@ static int f_getown_ex(struct file *filp, unsigned long arg) > } > read_unlock(&filp->f_owner.lock); > > - if (!ret) > + if (!ret) { > ret = copy_to_user(owner_p, &owner, sizeof(owner)); > + if (ret) > + ret = -EFAULT; > + } > return ret; > } > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/