From: Li Nan <linan122@huawei.com>

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>
---
 block/ioctl.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/block/ioctl.c b/block/ioctl.c
index 0c76137adcaa..a9028a2c2db5 100644
--- 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);
-- 
2.39.2

On Fri, 29 Mar 2024 09:23:19 +0800, linan666@huaweicloud.com wrote:
> 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.
> 
> 

Applied, thanks!

[1/1] block: fix overflow in blk_ioctl_discard()
      commit: 22d24a544b0d49bbcbd61c8c0eaf77d3c9297155

Best regards,
-- 
Jens Axboe

On Fri, Mar 29, 2024 at 09:23:19AM +0800, linan666@huaweicloud.com wrote:
> From: Li Nan <linan122@huawei.com>
> 
> 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.

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

Can you wire up a testcase in blktests for this condition?

在 2024/4/2 20:32, Christoph Hellwig 写道:
> On Fri, Mar 29, 2024 at 09:23:19AM +0800, linan666@huaweicloud.com wrote:
>> From: Li Nan <linan122@huawei.com>
>>
>> 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.
> 
> Looks good:
> 
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> 
> Can you wire up a testcase in blktests for this condition?
> 

It's my pleasure, I will add testcase later.

> 
> .

-- 
Thanks,
Nan