[PATCH] ntfs3: fix mapping pairs bounds check for alignment

[PATCH] ntfs3: fix mapping pairs bounds check for alignment

[Hongling Zeng]

In the UpdateMappingPairs action, the expansion check compares the
unaligned new attribute size with the available record space. The new
size is aligned to an 8-byte boundary before the mapping pairs are
updated, so the check can underestimate the required space by up to
seven bytes.

Use the aligned size in the expansion check to ensure that the
subsequent update cannot exceed the available record space.

Fixes: b46acd6a6a62 ("fs/ntfs3: Add NTFS journal")
Cc: stable@vger.kernel.org
Signed-off-by: Hongling Zeng <zenghongling@kylinos.cn>
---
 fs/ntfs3/fslog.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/ntfs3/fslog.c b/fs/ntfs3/fslog.c
index cc24c23e4db9..3440212ecb12 100644
--- a/fs/ntfs3/fslog.c
+++ b/fs/ntfs3/fslog.c
@@ -3388,7 +3388,8 @@ static int do_action(struct ntfs_log *log, struct OPEN_ATTR_ENRTY *oe,
 
 		if (!check_if_attr(rec, lrh) || !attr->non_res ||
 		    aoff < le16_to_cpu(attr->nres.run_off) || aoff > asize ||
-		    (nsize > asize && nsize - asize > record_size - used)) {
+		    (nsize > asize &&
+		     ALIGN(nsize, 8) - asize > record_size - used)) {
 			goto dirty_vol;
 		}
 
-- 
2.25.1

Re: [PATCH] ntfs3: fix mapping pairs bounds check for alignment

[Konstantin Komarov]

On 8/5/26 08:45, Hongling Zeng wrote:

> In the UpdateMappingPairs action, the expansion check compares the
> unaligned new attribute size with the available record space. The new
> size is aligned to an 8-byte boundary before the mapping pairs are
> updated, so the check can underestimate the required space by up to
> seven bytes.
>
> Use the aligned size in the expansion check to ensure that the
> subsequent update cannot exceed the available record space.
>
> Fixes: b46acd6a6a62 ("fs/ntfs3: Add NTFS journal")
> Cc: stable@vger.kernel.org
> Signed-off-by: Hongling Zeng <zenghongling@kylinos.cn>
> ---
>   fs/ntfs3/fslog.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ntfs3/fslog.c b/fs/ntfs3/fslog.c
> index cc24c23e4db9..3440212ecb12 100644
> --- a/fs/ntfs3/fslog.c
> +++ b/fs/ntfs3/fslog.c
> @@ -3388,7 +3388,8 @@ static int do_action(struct ntfs_log *log, struct OPEN_ATTR_ENRTY *oe,
>   
>   		if (!check_if_attr(rec, lrh) || !attr->non_res ||
>   		    aoff < le16_to_cpu(attr->nres.run_off) || aoff > asize ||
> -		    (nsize > asize && nsize - asize > record_size - used)) {
> +		    (nsize > asize &&
> +		     ALIGN(nsize, 8) - asize > record_size - used)) {
>   			goto dirty_vol;
>   		}
>   

Hello,

Your patch is applied, thanks.

Regards,
Konstantin