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Subject[PATCH v2] block/compat_ioctl: fix range check in BLKGETSIZE
From
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>
---
block/ioctl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

v2: addressed bart's comment

diff --git a/block/ioctl.c b/block/ioctl.c
index 4a86340133e4..f8703db99c73 100644
--- 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));

--
2.36.0.rc0.470.gd361397f0d-goog
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