Re: [PATCH v2] nilfs2: validate file block counts during recovery

[Viacheslav Dubeyko]

On Tue, 2026-09-15 at 16:57 -0300, Aldo Ariel Panzardo wrote:
> nilfs_scan_dsync_log() trusts the block counts in each on-disk file
> information entry. If fi_ndatablk is greater than fi_nblocks, the
> data
> block loop can consume excessive summary entries and the later
> subtraction
> used to derive the number of node blocks underflows.
> 
> Reject inconsistent file information entries before consuming their
> block
> information.
> 
> Fixes: 0f3e1c7f23f8 ("nilfs2: recovery functions")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Aldo Ariel Panzardo <qwe.aldo@xxxxxxxxx>
> ---
>  fs/nilfs2/recovery.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/fs/nilfs2/recovery.c b/fs/nilfs2/recovery.c
> index 4d5a6aa521..28200cef4d 100644
> --- a/fs/nilfs2/recovery.c
> +++ b/fs/nilfs2/recovery.c
> @@ -359,6 +359,10 @@ static int nilfs_scan_dsync_log(struct the_nilfs
> *nilfs, sector_t start_blocknr,
>  		ino = le64_to_cpu(finfo->fi_ino);
>  		nblocks = le32_to_cpu(finfo->fi_nblocks);
>  		ndatablk = le32_to_cpu(finfo->fi_ndatablk);
> +		if (ndatablk > nblocks) {
> +			err = -EIO;
> +			goto out;
> +		}
>  		nnodeblk = nblocks - ndatablk;
>  
>  		while (ndatablk-- > 0) {

Looks good.

Reviewed-by: Viacheslav Dubeyko <slava@xxxxxxxxxxx>

Thanks,
Slava.