block/compat_ioctl: fix range check in BLKGETSIZE

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>

diff --git a/block/ioctl.c b/block/ioctl.c
index 4a86340133e46b2465ed0de12fbf81b836ee81c3..f8703db99c734a7d6724e08113d6a09f43837b9f 100644 (file)
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -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));