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Date:   Mon, 23 May 2022 12:39:12 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Christoph Hellwig <hch@infradead.org>
Cc:     Maninder Singh <maninder1.s@samsung.com>, pmladek@suse.com,
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Subject: Re: [PATCH 0/5] kallsyms: make kallsym APIs more safe with scnprintf
Message-ID: <202205231238.FAF6D28@keescook>
References: <CGME20220520083715epcas5p400b11adef4d540756c985feb20ba29bc@epcas5p4.samsung.com>
 <20220520083701.2610975-1-maninder1.s@samsung.com>
 <YonTOL4zC4CytVrn@infradead.org>
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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