Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753290Ab3FFQLP (ORCPT ); Thu, 6 Jun 2013 12:11:15 -0400 Received: from mail-pd0-f179.google.com ([209.85.192.179]:37975 "EHLO mail-pd0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753232Ab3FFQLM (ORCPT ); Thu, 6 Jun 2013 12:11:12 -0400 From: Jiang Liu To: Greg Kroah-Hartman , Nitin Gupta , Minchan Kim , Jerome Marchand Cc: Jiang Liu , devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH v3 05/10] zram: avoid access beyond the zram device Date: Fri, 7 Jun 2013 00:07:26 +0800 Message-Id: <1370534851-26056-6-git-send-email-jiang.liu@huawei.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1370534851-26056-1-git-send-email-jiang.liu@huawei.com> References: <1370534851-26056-1-git-send-email-jiang.liu@huawei.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1759 Lines: 50 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)) 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/