[PATCH 5.17 004/146] block/compat_ioctl: fix range check in BLKGETSIZE

From: Greg Kroah-Hartman
Date: Tue Apr 26 2022 - 05:23:39 EST


From: Khazhismel Kumykov <khazhy@xxxxxxxxxx>

commit ccf16413e520164eb718cf8b22a30438da80ff23 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@xxxxxxx>
Signed-off-by: Khazhismel Kumykov <khazhy@xxxxxxxxxx>
Reviewed-by: Chaitanya Kulkarni <kch@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220414224056.2875681-1-khazhy@xxxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
block/ioctl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -629,7 +629,7 @@ long compat_blkdev_ioctl(struct file *fi
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));