# Re: \[PATCH 0/5\] kallsyms: make kallsym APIs more safe with scnprintf

- From: Christoph Hellwig \<hch@infradead.org\>
- Date: 2022-05-22 06:09:18 
- List: linux-modules
- Page: https://ratatoskr.run/linux-modules/2022/05/229470
- Thread: https://ratatoskr.run/linuxppc-dev/2022/05/229387/t.md

```text
On Fri, May 20, 2022 at 02:06:56PM +0530, Maninder Singh wrote:
> kallsyms functionality depends on KSYM_NAME_LEN directly.
> but if user passed array length lesser than it, sprintf
> can cause issues of buffer overflow attack.
> 
> So changing *sprint* and *lookup* APIs in this patch set
> to have buffer size as an argument and replacing sprintf with
> scnprintf.

This is still a pretty horrible API.  Passing something like
a struct seq_buf seems like the much better API here.  Also with
the amount of arguments and by reference passing it might be worth
to pass them as a structure while you're at it.

```