From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932463AbeDWUIa (ORCPT ); Mon, 23 Apr 2018 16:08:30 -0400 Received: from mail-vk0-f66.google.com ([209.85.213.66]:40053 "EHLO mail-vk0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932306AbeDWUI3 (ORCPT ); Mon, 23 Apr 2018 16:08:29 -0400 X-Google-Smtp-Source: AIpwx49iicc2R8W3P2Ie0JQ1txW6wbcX3L4F0XU4Czwx1/qr/1zsFjC7avZoFHjMtAdx5GrOwLnJi7RYJnLeRv91d58= MIME-Version: 1.0 In-Reply-To: <20180423200255.154645-1-ksspiers@google.com> References: <20180423200255.154645-1-ksspiers@google.com> From: Kees Cook Date: Mon, 23 Apr 2018 13:08:27 -0700 X-Google-Sender-Auth: qrmilydhxBYNtZR01B1Ne2W4V4E Message-ID: Subject: Re: [PATCH] rave-sp: Remove VLA To: Kyle Spiers Cc: Lee Jones , LKML Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 23, 2018 at 1:02 PM, Kyle Spiers wrote: > As part of the effort to remove VLAs from the kernel[1], this creates > constants for the checksum lengths of CCITT and 8B2C and changes > crc_calculated to be the maximum size of a checksum. > > https://lkml.org/lkml/2018/3/7/621 > > Signed-off-by: Kyle Spiers Reviewed-by: Kees Cook -Kees > --- > drivers/mfd/rave-sp.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/drivers/mfd/rave-sp.c b/drivers/mfd/rave-sp.c > index 5c858e784a89..99fa482419f9 100644 > --- a/drivers/mfd/rave-sp.c > +++ b/drivers/mfd/rave-sp.c > @@ -45,7 +45,9 @@ > #define RAVE_SP_DLE 0x10 > > #define RAVE_SP_MAX_DATA_SIZE 64 > -#define RAVE_SP_CHECKSUM_SIZE 2 /* Worst case scenario on RDU2 */ > +#define RAVE_SP_CHECKSUM_8B2C 1 > +#define RAVE_SP_CHECKSUM_CCITT 2 > +#define RAVE_SP_CHECKSUM_SIZE RAVE_SP_CHECKSUM_CCITT > /* > * We don't store STX, ETX and unescaped bytes, so Rx is only > * DATA + CSUM > @@ -415,7 +417,12 @@ static void rave_sp_receive_frame(struct rave_sp *sp, > const size_t payload_length = length - checksum_length; > const u8 *crc_reported = &data[payload_length]; > struct device *dev = &sp->serdev->dev; > - u8 crc_calculated[checksum_length]; > + u8 crc_calculated[RAVE_SP_CHECKSUM_SIZE]; > + > + if (unlikely(length > sizeof(crc_calculated))) { > + dev_warn(dev, "Dropping oversized frame\n"); > + return; > + } > > print_hex_dump(KERN_DEBUG, "rave-sp rx: ", DUMP_PREFIX_NONE, > 16, 1, data, length, false); > -- > 2.17.0.484.g0c8726318c-goog > -- Kees Cook Pixel Security