Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752731AbaG1IcF (ORCPT ); Mon, 28 Jul 2014 04:32:05 -0400 Received: from mail-ie0-f178.google.com ([209.85.223.178]:62764 "EHLO mail-ie0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751394AbaG1Ib7 (ORCPT ); Mon, 28 Jul 2014 04:31:59 -0400 MIME-Version: 1.0 In-Reply-To: <1406393198-5306-1-git-send-email-rickard_strandqvist@spectrumdigital.se> References: <1406393198-5306-1-git-send-email-rickard_strandqvist@spectrumdigital.se> Date: Mon, 28 Jul 2014 10:31:58 +0200 Message-ID: Subject: Re: [PATCH] hid: uhid.c: Cleaning up missing null-terminate in conjunction with strncpy From: David Herrmann To: Rickard Strandqvist Cc: David Herrmann , Jiri Kosina , "open list:HID CORE LAYER" , linux-kernel Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi On Sat, Jul 26, 2014 at 6:46 PM, Rickard Strandqvist wrote: > Replacing strncpy with strlcpy to avoid strings that lacks null terminate. > And removed unnecessary magic numbers. > > Signed-off-by: Rickard Strandqvist > --- > drivers/hid/uhid.c | 18 ++++++------------ > 1 file changed, 6 insertions(+), 12 deletions(-) > > diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c > index 0cb92e3..b72ab0c 100644 > --- a/drivers/hid/uhid.c > +++ b/drivers/hid/uhid.c > @@ -392,12 +392,9 @@ static int uhid_dev_create(struct uhid_device *uhid, > goto err_free; > } > > - strncpy(hid->name, ev->u.create.name, 127); > - hid->name[127] = 0; > - strncpy(hid->phys, ev->u.create.phys, 63); > - hid->phys[63] = 0; > - strncpy(hid->uniq, ev->u.create.uniq, 63); > - hid->uniq[63] = 0; > + strlcpy(hid->name, ev->u.create.name, sizeof(hid->name)); > + strlcpy(hid->phys, ev->u.create.phys, sizeof(hid->phys)); > + strlcpy(hid->uniq, ev->u.create.uniq, sizeof(hid->uniq)); NAK, this patch is wrong. strlcpy() is *not* a replacement for strncpy(). Please see lib/string.c or the man-page of strlcpy(3). It calls strlen() on the source, which strncpy() does not. "ev" was copied unmodified from user-space and might not be NULL-terminated, therefore, strncpy() is the right choice. Btw., please avoid commit-messages that sound like bug-fixes, which this definitely is not. hid_allocate_device() cleans the object to ZERO, therefore, you're guaranteed that there's a proper NULL-terminator, independent of the contents of ev->u.xyz. Thanks David > hid->ll_driver = &uhid_hid_driver; > hid->bus = ev->u.create.bus; > @@ -452,12 +449,9 @@ static int uhid_dev_create2(struct uhid_device *uhid, > goto err_free; > } > > - strncpy(hid->name, ev->u.create2.name, 127); > - hid->name[127] = 0; > - strncpy(hid->phys, ev->u.create2.phys, 63); > - hid->phys[63] = 0; > - strncpy(hid->uniq, ev->u.create2.uniq, 63); > - hid->uniq[63] = 0; > + strlcpy(hid->name, ev->u.create2.name, sizeof(hid->name)); > + strlcpy(hid->phys, ev->u.create2.phys, sizeof(hid->phys)); > + strlcpy(hid->uniq, ev->u.create2.uniq, sizeof(hid->uniq)); > > hid->ll_driver = &uhid_hid_driver; > hid->bus = ev->u.create2.bus; > -- > 1.7.10.4 > -- 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/