From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751725AbaC2O2x (ORCPT ); Sat, 29 Mar 2014 10:28:53 -0400 Received: from mail-pb0-f51.google.com ([209.85.160.51]:53203 "EHLO mail-pb0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751523AbaC2O2w (ORCPT ); Sat, 29 Mar 2014 10:28:52 -0400 From: Akinobu Mita To: linux-kernel@vger.kernel.org Cc: Akinobu Mita , Jens Axboe Subject: [PATCH] block: fix BLKSECTGET ioctl when max_sectors is greater than USHRT_MAX Date: Sat, 29 Mar 2014 23:28:41 +0900 Message-Id: <1396103322-3519-1-git-send-email-akinobu.mita@gmail.com> X-Mailer: git-send-email 1.8.3.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org BLKSECTGET ioctl loads the request queue's max_sectors as unsigned short value to the argument pointer. So if the max_sector is greater than USHRT_MAX, the upper 16 bits of that is just discarded. In such case, USHRT_MAX is more preferable than the lower 16 bits of max_sectors. Signed-off-by: Akinobu Mita Cc: Jens Axboe --- block/compat_ioctl.c | 6 ++++-- block/ioctl.c | 5 ++++- 2 files changed, 8 insertions(+), 3 deletions(-) diff --git a/block/compat_ioctl.c b/block/compat_ioctl.c index fbd5a67..e0393cd 100644 --- a/block/compat_ioctl.c +++ b/block/compat_ioctl.c @@ -663,6 +663,7 @@ long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg) fmode_t mode = file->f_mode; struct backing_dev_info *bdi; loff_t size; + unsigned int max_sectors; /* * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have @@ -718,8 +719,9 @@ long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg) case BLKSSZGET: /* get block device hardware sector size */ return compat_put_int(arg, bdev_logical_block_size(bdev)); case BLKSECTGET: - return compat_put_ushort(arg, - queue_max_sectors(bdev_get_queue(bdev))); + max_sectors = min_t(unsigned int, USHRT_MAX, + queue_max_sectors(bdev_get_queue(bdev))); + return compat_put_ushort(arg, max_sectors); case BLKROTATIONAL: return compat_put_ushort(arg, !blk_queue_nonrot(bdev_get_queue(bdev))); diff --git a/block/ioctl.c b/block/ioctl.c index 7d5c3b2..d6cda81 100644 --- a/block/ioctl.c +++ b/block/ioctl.c @@ -278,6 +278,7 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd, struct backing_dev_info *bdi; loff_t size; int ret, n; + unsigned int max_sectors; switch(cmd) { case BLKFLSBUF: @@ -375,7 +376,9 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd, case BLKDISCARDZEROES: return put_uint(arg, bdev_discard_zeroes_data(bdev)); case BLKSECTGET: - return put_ushort(arg, queue_max_sectors(bdev_get_queue(bdev))); + max_sectors = min_t(unsigned int, USHRT_MAX, + queue_max_sectors(bdev_get_queue(bdev))); + return put_ushort(arg, max_sectors); case BLKROTATIONAL: return put_ushort(arg, !blk_queue_nonrot(bdev_get_queue(bdev))); case BLKRASET: -- 1.8.3.2