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

- From: Kees Cook \<hidden\>
- Date: 2022-05-23 19:43:20 
- List: linux-modules
- Page: https://ratatoskr.run/linux-modules/2022/05/229560
- Thread: https://ratatoskr.run/linuxppc-dev/2022/05/229387/t.md

```text
On Sat, May 21, 2022 at 11:07:52PM -0700, Christoph Hellwig wrote:
> 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.

Yeah, I agree. It really seems like seq_buf would be nicer.

-- 
Kees Cook
```