Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754215Ab3FGJks (ORCPT ); Fri, 7 Jun 2013 05:40:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39277 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753887Ab3FGJkp (ORCPT ); Fri, 7 Jun 2013 05:40:45 -0400 Message-ID: <51B1AA8A.4010005@redhat.com> Date: Fri, 07 Jun 2013 11:40:26 +0200 From: Jerome Marchand User-Agent: Mozilla/5.0 (X11; Linux i686; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 MIME-Version: 1.0 To: Minchan Kim CC: Jiang Liu , Greg Kroah-Hartman , Nitin Gupta , Jiang Liu , devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v3 05/10] zram: avoid access beyond the zram device References: <1370534851-26056-1-git-send-email-jiang.liu@huawei.com> <1370534851-26056-6-git-send-email-jiang.liu@huawei.com> <20130607080945.GD22516@blaptop> In-Reply-To: <20130607080945.GD22516@blaptop> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2350 Lines: 67 On 06/07/2013 10:09 AM, Minchan Kim wrote: > On Fri, Jun 07, 2013 at 12:07:26AM +0800, Jiang Liu wrote: >> Function valid_io_request() should verify the entire request are within >> the zram device address range. Otherwise it may cause invalid memory >> access when accessing/modifying zram->meta->table[index] because the >> 'index' is out of range. Then it may access non-exist memory, randomly >> modify memory belong to other subsystems, which is hard to track down. >> >> Signed-off-by: Jiang Liu >> Cc: stable@vger.kernel.org >> --- >> drivers/staging/zram/zram_drv.c | 17 ++++++++++++----- >> 1 file changed, 12 insertions(+), 5 deletions(-) >> >> diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c >> index 27ab824..9289217 100644 >> --- a/drivers/staging/zram/zram_drv.c >> +++ b/drivers/staging/zram/zram_drv.c >> @@ -420,13 +420,20 @@ out: >> */ >> static inline int valid_io_request(struct zram *zram, struct bio *bio) >> { >> - if (unlikely( >> - (bio->bi_sector >= (zram->disksize >> SECTOR_SHIFT)) || >> - (bio->bi_sector & (ZRAM_SECTOR_PER_LOGICAL_BLOCK - 1)) || >> - (bio->bi_size & (ZRAM_LOGICAL_BLOCK_SIZE - 1)))) { >> + u64 start, end, bound; >> + >> + /* unaligned request */ >> + if (unlikely(bio->bi_sector & (ZRAM_SECTOR_PER_LOGICAL_BLOCK - 1))) >> + return 0; >> + if (unlikely(bio->bi_size & (ZRAM_LOGICAL_BLOCK_SIZE - 1))) >> + return 0; >> >> + start = bio->bi_sector; >> + end = start + (bio->bi_size >> SECTOR_SHIFT); >> + bound = zram->disksize >> SECTOR_SHIFT; >> + /* out of range range */ >> + if (unlikely(start >= bound || end >= bound || start > end)) > > if (end >= bound || start > end) isn't enough? I shall think so. Jerome > >> return 0; >> - } >> >> /* I/O request is valid */ >> return 1; >> -- >> 1.8.1.2 >> >> -- >> 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/ > -- 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/