block: fix overflow in blk_ioctl_discard()

There is no check for overflow of 'start + len' in blk_ioctl_discard().
Hung task occurs if submit an discard ioctl with the following param:
  start = 0x80000000000ff000, len = 0x8000000000fff000;
Add the overflow validation now.

Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240329012319.2034550-1-linan666@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/ioctl.c b/block/ioctl.c
index 0c76137adcaaa5b9d212d789291d681c23c064f6..a9028a2c2db57b0881b7faf7cee2243148d1626c 100644 (file)
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -96,7 +96,7 @@ static int blk_ioctl_discard(struct block_device *bdev, blk_mode_t mode,
                unsigned long arg)
 {
        uint64_t range[2];
-       uint64_t start, len;
+       uint64_t start, len, end;
        struct inode *inode = bdev->bd_inode;
        int err;
 
@@ -117,7 +117,8 @@ static int blk_ioctl_discard(struct block_device *bdev, blk_mode_t mode,
        if (len & 511)
                return -EINVAL;
 
-       if (start + len > bdev_nr_bytes(bdev))
+       if (check_add_overflow(start, len, &end) ||
+           end > bdev_nr_bytes(bdev))
                return -EINVAL;
 
        filemap_invalidate_lock(inode->i_mapping);