From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751828Ab1BPPJo (ORCPT ); Wed, 16 Feb 2011 10:09:44 -0500 Received: from mx1.redhat.com ([209.132.183.28]:52642 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751278Ab1BPPJm (ORCPT ); Wed, 16 Feb 2011 10:09:42 -0500 Date: Wed, 16 Feb 2011 17:09:33 +0200 From: Gleb Natapov To: linux-kernel@vger.kernel.org Cc: "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , x86@kernel.org Subject: Re: [PATCHv2] Fix EDD3.0 data verification. Message-ID: <20110216150933.GE14984@redhat.com> References: <20110203122948.GX14984@redhat.com> <20110208145301.GO14984@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110208145301.GO14984@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 08, 2011 at 04:53:01PM +0200, Gleb Natapov wrote: > Peter, ping. > > Is this version acceptable? > Ping? > On Thu, Feb 03, 2011 at 02:29:48PM +0200, Gleb Natapov wrote: > > Check for nonzero path in edd_has_edd30() has no sense. First, it looks > > at the wrong memory. Device path starts at offset 30 of the info->params > > structure which is at offset 8 from the beginning of info structure, but > > code looks at info + 4 instead. This was correct when code was introduced, > > but around v2.6.4 three more fields were added to edd_info structure > > (commit 66b61a5c in history.git). Second, even if it will check correct > > memory it will always succeed since at offset 30 (params->key) there will > > be non-zero values otherwise previous check would fail. > > > > The patch replaces this bogus check with one that verifies checksum. > > > > Signed-off-by: Gleb Natapov > > --- > > v1->v2 > > use device path info length to calculate csum. > > > > diff --git a/drivers/firmware/edd.c b/drivers/firmware/edd.c > > index 96c25d9..f1b7f65 100644 > > --- a/drivers/firmware/edd.c > > +++ b/drivers/firmware/edd.c > > @@ -531,8 +531,8 @@ static int > > edd_has_edd30(struct edd_device *edev) > > { > > struct edd_info *info; > > - int i, nonzero_path = 0; > > - char c; > > + int i; > > + u8 csum = 0; > > > > if (!edev) > > return 0; > > @@ -544,16 +544,16 @@ edd_has_edd30(struct edd_device *edev) > > return 0; > > } > > > > - for (i = 30; i <= 73; i++) { > > - c = *(((uint8_t *) info) + i + 4); > > - if (c) { > > - nonzero_path++; > > - break; > > - } > > - } > > - if (!nonzero_path) { > > + > > + /* We support only T13 spec */ > > + if (info->params.device_path_info_length != 44) > > + return 0; > > + > > + for (i = 30; i < info->params.device_path_info_length + 30; i++) > > + csum += *(((u8 *)&info->params) + i); > > + > > + if (csum) > > return 0; > > - } > > > > return 1; > > } > > -- > > Gleb. > > -- > > 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/ > > -- > Gleb. > -- > 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/ -- Gleb.