[PATCH AUTOSEL 6.6 08/12] block: fix overflow in blk_ioctl_discard()

[Sasha Levin]

From: Li Nan <linan122@xxxxxxxxxx>

[ Upstream commit 22d24a544b0d49bbcbd61c8c0eaf77d3c9297155 ]

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@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Link: https://lore.kernel.org/r/20240329012319.2034550-1-linan666@xxxxxxxxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 block/ioctl.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/block/ioctl.c b/block/ioctl.c
index d1d8e8391279a..68265f914c27b 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -89,7 +89,7 @@ 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;
 
@@ -110,7 +110,8 @@ 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);
-- 
2.43.0