block/compat_ioctl: fix range check in BLKGETSIZE

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@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>

diff --git a/block/ioctl.c b/block/ioctl.c
index a31be7f..cd506a9 100644 (file)
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -645,7 +645,7 @@ long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
                        (bdev->bd_disk->bdi->ra_pages * PAGE_SIZE) / 512);
        case BLKGETSIZE:
                size = i_size_read(bdev->bd_inode);
-               if ((size >> 9) > ~0UL)
+               if ((size >> 9) > ~(compat_ulong_t)0)
                        return -EFBIG;
                return compat_put_ulong(argp, size >> 9);