Re: [PATCH] udf: NULL dereference at udf_symlink() on error

[Jan Kara <jack@suse.cz>]

On Mon 23-03-15 02:11:49, Changwoo Min wrote:
> There is no check for udf_tgetblk(), which could return NULL, in udf_symlink(). 
> So there is a possibility of returning NULL under heavy memory pressure and 
> possibility of NULL dereference. 
> 
> Signed-off-by: Changwoo Min <changwoo.m@gmail.com>
> ---
>  fs/udf/namei.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/fs/udf/namei.c b/fs/udf/namei.c
> index 33b246b..ed2f221 100644
> --- a/fs/udf/namei.c
> +++ b/fs/udf/namei.c
> @@ -902,6 +902,10 @@ static int udf_symlink(struct inode *dir, struct dentry *dentry,
>  				iinfo->i_location.partitionReferenceNum,
>  				0);
>  		epos.bh = udf_tgetblk(sb, block);
> +		if (!epos.bh) {
> +			err = -ENOMEM;
  This should be -EIO as per our discussion at the previous patch.
Otherwise I agree.

								Honza

> +			goto out_no_entry;
> +		}
>  		lock_buffer(epos.bh);
>  		memset(epos.bh->b_data, 0x00, bsize);
>  		set_buffer_uptodate(epos.bh);
> -- 
> 1.9.1
> 
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR