linux-kernel - Re: [PATCH 0/5] kallsyms: make kallsym APIs more safe with scnprintf

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Date:   Sat, 21 May 2022 23:07:52 -0700
From:   Christoph Hellwig <hch@...radead.org>
To:     Maninder Singh <maninder1.s@...sung.com>
Cc:     keescook@...omium.org, pmladek@...e.com, bcain@...cinc.com,
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Subject: Re: [PATCH 0/5] kallsyms: make kallsym APIs more safe with scnprintf

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.