[PATCH] xfs: fix the problem that the array may be out of bound

[PATCH] xfs: fix the problem that the array may be out of bound

[zhangyue]

In function 'xfs_btree_delrec()', if all data in array
'cur->bc_ptrs[level]' is 0, the 'level' may be greater than
or equal to 'XFS_BTREE_MAXLEVELS'.

At this time, the array may be out of bound.

Signed-off-by: zhangyue <zhangyue1@kylinos.cn>
---
 fs/xfs/libxfs/xfs_btree.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
index bbdae2b4559f..fe66d1adc169 100644
--- a/fs/xfs/libxfs/xfs_btree.c
+++ b/fs/xfs/libxfs/xfs_btree.c
@@ -3694,6 +3694,9 @@ xfs_btree_delrec(
 	tcur = NULL;
 
 	/* Get the index of the entry being deleted, check for nothing there. */
+	if (level >= XFS_BTREE_MAXLEVELS)
+		return -EFSCORRUPTED;
+
 	ptr = cur->bc_ptrs[level];
 	if (ptr == 0) {
 		*stat = 0;
-- 
2.30.0

Re: [PATCH] xfs: fix the problem that the array may be out of bound

[Darrick J. Wong]

On Fri, Nov 19, 2021 at 04:17:58PM +0800, zhangyue wrote:
> In function 'xfs_btree_delrec()', if all data in array
> 'cur->bc_ptrs[level]' is 0, the 'level' may be greater than
> or equal to 'XFS_BTREE_MAXLEVELS'.
> 
> At this time, the array may be out of bound.
> 
> Signed-off-by: zhangyue <zhangyue1@kylinos.cn>

I /think/ this is no longer necessary since XFS_BTREE_MAXLEVELS went
away in 5.16, but if you disagree, please resend.

--D

> ---
>  fs/xfs/libxfs/xfs_btree.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
> index bbdae2b4559f..fe66d1adc169 100644
> --- a/fs/xfs/libxfs/xfs_btree.c
> +++ b/fs/xfs/libxfs/xfs_btree.c
> @@ -3694,6 +3694,9 @@ xfs_btree_delrec(
>  	tcur = NULL;
>  
>  	/* Get the index of the entry being deleted, check for nothing there. */
> +	if (level >= XFS_BTREE_MAXLEVELS)
> +		return -EFSCORRUPTED;
> +
>  	ptr = cur->bc_ptrs[level];
>  	if (ptr == 0) {
>  		*stat = 0;
> -- 
> 2.30.0
>