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block/compat_ioctl: fix range check in BLKGETSIZE
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commit ccf1641 upstream.

kernel ulong and compat_ulong_t may not be same width. Use type directly
to eliminate mismatches.

This would result in truncation rather than EFBIG for 32bit mode for
large disks.

Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Khazhismel Kumykov <khazhy@google.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220414224056.2875681-1-khazhy@google.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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khazhyk authored and gregkh committed Apr 27, 2022
1 parent 29186fd commit 3341481
Showing 1 changed file with 1 addition and 1 deletion.
2 changes: 1 addition & 1 deletion block/ioctl.c
Original file line number Diff line number Diff line change
Expand Up @@ -629,7 +629,7 @@ long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
return compat_put_long(argp,
(bdev->bd_disk->bdi->ra_pages * PAGE_SIZE) / 512);
case BLKGETSIZE:
if (bdev_nr_sectors(bdev) > ~0UL)
if (bdev_nr_sectors(bdev) > ~(compat_ulong_t)0)
return -EFBIG;
return compat_put_ulong(argp, bdev_nr_sectors(bdev));

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