From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752377AbbIPC2F (ORCPT ); Tue, 15 Sep 2015 22:28:05 -0400 Received: from mail-oi0-f52.google.com ([209.85.218.52]:33709 "EHLO mail-oi0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751772AbbIPC2C (ORCPT ); Tue, 15 Sep 2015 22:28:02 -0400 Subject: Re: [PATCH] drivers: of: check input parameter name for __of_find_property To: Peng Fan References: <1441979043-19694-1-git-send-email-van.freenix@gmail.com> <55F83FAC.5080002@kernel.org> <20150916001650.GA28082@linux-4gyl.site> Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Frank Rowand , Grant Likely From: Rob Herring X-Enigmail-Draft-Status: N1110 Message-ID: <55F8D3AF.9070503@kernel.org> Date: Tue, 15 Sep 2015 21:27:59 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <20150916001650.GA28082@linux-4gyl.site> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/15/2015 07:16 PM, Peng Fan wrote: > Hi Rob, > > On Tue, Sep 15, 2015 at 10:56:28AM -0500, Rob Herring wrote: >> On 09/11/2015 08:44 AM, Peng Fan wrote: >>> Check input parameter 'name' for __of_find_property. If name is NULL, >>> of_prop_cmp->strcasecmp may trigger panic. >> >> Arguably that could be a feature. Do you have a usecase where name being >> NULL is valid and panicking is a problem? > > In drivers/pinctrl/devicetree.c > > 195 propname = kasprintf(GFP_KERNEL, "pinctrl-%d", state); > 196 prop = of_find_property(np, propname, &size); > 197 kfree(propname); > 198 if (!prop) > 199 break; > > If propname is NULL, of_find_property may trigger panic. Anyway propname should be checked > before passing to of_find_property. propname will only be NULL if the memory allocation failed which gives you a big warning message. I don't think you would want to continue on in this case. So I'm inclined to leave this as is with passing NULL to of_find_property to always be an error and fatal. Rob > I did not met panic message. I wrote this patch when I was reading the piece code. > I think the name parameter should be checked before doing string compare. > > Regards, > Peng. > >> >> Rob >> >>> >>> Signed-off-by: Peng Fan >>> Cc: Rob Herring >>> Cc: Frank Rowand >>> Cc: Grant Likely >>> --- >>> drivers/of/base.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/drivers/of/base.c b/drivers/of/base.c >>> index 8b5a187..e41436d 100644 >>> --- a/drivers/of/base.c >>> +++ b/drivers/of/base.c >>> @@ -215,7 +215,7 @@ static struct property *__of_find_property(const struct device_node *np, >>> { >>> struct property *pp; >>> >>> - if (!np) >>> + if (!np || !name) >>> return NULL; >>> >>> for (pp = np->properties; pp; pp = pp->next) { >>> >>