[U-Boot] [PATCH 1/1] ubifs: avoid possible NULL dereference

[Ladislav Michl]

On Tue, Nov 21, 2017 at 07:45:03PM +0100, Heinrich Schuchardt wrote:
> If 'file' cannot be allocated due to an out of memory
> situation, do not dereference it.
> 
> When debugging this patch also avoids a misleading message
> "cannot find next direntry, error %d" in case of an out of
> memory situation. It is sufficent to write
> "%s: Error, no memory for malloc!\n" in this case.
> 
> Reported-by: Alex Sadovsky <nable.maininbox at googlemail.com>
> Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
> ---
>  fs/ubifs/ubifs.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/ubifs/ubifs.c b/fs/ubifs/ubifs.c
> index 4465523d5f..313dee0579 100644
> --- a/fs/ubifs/ubifs.c
> +++ b/fs/ubifs/ubifs.c
> @@ -403,8 +403,7 @@ static int ubifs_finddir(struct super_block *sb, char *dirname,
>  	dir = kzalloc(sizeof(struct inode), 0);
>  	if (!file || !dentry || !dir) {
>  		printf("%s: Error, no memory for malloc!\n", __func__);
> -		err = -ENOMEM;
> -		goto out;
> +		goto out_nomem;
>  	}
>  
>  	dir->i_sb = sb;
> @@ -424,7 +423,6 @@ static int ubifs_finddir(struct super_block *sb, char *dirname,
>  		err = PTR_ERR(dent);
>  		goto out;
>  	}
> -
>  	file->f_pos = key_hash_flash(c, &dent->key);
>  	file->private_data = dent;
>
  
This hunk should be probably droped.

> @@ -463,6 +461,7 @@ out:
>  
>  out_free:
>  	kfree(file->private_data);

Now question is why is file->private_data ever assigned as it seems nothing
works with it.

> +out_nomem:
>  	free(file);
>  	free(dentry);
>  	free(dir);
> -- 
> 2.11.0
> 
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