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Date:   Wed, 14 Jun 2023 12:28:18 -0700
From:   Kees Cook <keescook@chromium.org>
To:     John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc:     ysato@users.sourceforge.jp, azeemshaikh38@gmail.com,
        dalias@libc.org, linux-kernel@vger.kernel.org,
        rdunlap@infradead.org, linux-sh@vger.kernel.org,
        linux-hardening@vger.kernel.org
Subject: Re: [PATCH] sh: Replace all non-returning strlcpy with strscpy
Message-ID: <202306141227.D4B2F1F6@keescook>
References: <20230530163041.985456-1-azeemshaikh38@gmail.com>
 <168676826702.1963449.9061022814058323294.b4-ty@chromium.org>
 <2a1d8002f7e2982399cb8ab7641f54ac867270aa.camel@physik.fu-berlin.de>
 <202306141203.0CAB93DD13@keescook>
 <af114229f6231ec180266eebce4e62851732a446.camel@physik.fu-berlin.de>
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On Wed, Jun 14, 2023 at 09:23:49PM +0200, John Paul Adrian Glaubitz wrote:
> On Wed, 2023-06-14 at 12:03 -0700, Kees Cook wrote:
> > On Wed, Jun 14, 2023 at 08:49:13PM +0200, John Paul Adrian Glaubitz wrote:
> > > Hi Kees!
> > > 
> > > On Wed, 2023-06-14 at 11:44 -0700, Kees Cook wrote:
> > > > On Tue, 30 May 2023 16:30:41 +0000, Azeem Shaikh wrote:
> > > > > strlcpy() reads the entire source buffer first.
> > > > > This read may exceed the destination size limit.
> > > > > This is both inefficient and can lead to linear read
> > > > > overflows if a source string is not NUL-terminated [1].
> > > > > In an effort to remove strlcpy() completely [2], replace
> > > > > strlcpy() here with strscpy().
> > > > > No return values were used, so direct replacement is safe.
> > > > > 
> > > > > [...]
> > > > 
> > > > Build tested with sh4 GCC 13.1 from:
> > > > https://mirrors.edge.kernel.org/pub/tools/crosstool/files/bin/x86_64/13.1.0/
> > > > 
> > > > with defconfig and:
> > > > 	CONFIG_CPU_SUBTYPE_SH7343=y
> > > > 	CONFIG_SH_DMA=y
> > > > 	CONFIG_SH_DMA_API=y
> > > > 
> > > > Applied to for-next/hardening, thanks!
> > > > 
> > > > [1/1] sh: Replace all non-returning strlcpy with strscpy
> > > >       https://git.kernel.org/kees/c/ca64da3052be
> > > > 
> > > 
> > > Apologies, this fell off my table. I should have acked and tested this being the
> > > SuperH maintainer. If you can still update the patch in your tree, I can both
> > > test and ack this patch.
> > 
> > Absolutely! Thanks for double-checking. :)
> 
> I have tested the patch on my SH-7785LCR board on top of Linus' tree and
> also acked it.

Awesome. :) I have updated the tags and will push out my tree shortly.

Thanks!

-Kees

-- 
Kees Cook