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From: Justin Stitt <justinstitt@google.com>
To: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>, Dave Young <dyoung@redhat.com>,
	kexec@lists.infradead.org,  linux-kernel@vger.kernel.org,
	linux-fsdevel@vger.kernel.org,  linux-hardening@vger.kernel.org
Subject: Re: [PATCH] vmcore: replace strncpy with strtomem
Date: Thu, 28 Mar 2024 13:42:15 -0700	[thread overview]
Message-ID: <CAFhGd8pU-utbgHhU5s_20pC_aNK7xtsJDbf+Ayg4Dck2K=4kag@mail.gmail.com> (raw)
In-Reply-To: <ZgTMZ1HYheBMDbei@MiWiFi-R3L-srv>

Hi,

On Wed, Mar 27, 2024 at 6:48 PM Baoquan He <bhe@redhat.com> wrote:
> > Mark these buffers as __nonstring and use strtomem_pad.
>
> Thanks.
>
> I didn't build, wondering if '__nonstring' has to be set so that
> strtomem_pad() can be used.

I do not believe marking buffers as __nonstring is strictly a
requirement. However, the documentation from string.h +302 says we
should do it:
/**
 * strtomem_pad - Copy NUL-terminated string to non-NUL-terminated buffer
 *
 * @dest: Pointer of destination character array (marked as __nonstring)
...

and so does [1] ... "mark the destination buffer variable (or
structure member) with the __nonstring attribute..."

FWIW, this builds just fine without the __nonstring attribute but we
should use it :)

>
> Thanks
> Baoquan
>

[1] https://github.com/KSPP/linux/issues/90

Thanks
Justin

WARNING: multiple messages have this Message-ID (diff)
From: Justin Stitt <justinstitt@google.com>
To: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>, Dave Young <dyoung@redhat.com>,
	kexec@lists.infradead.org,  linux-kernel@vger.kernel.org,
	linux-fsdevel@vger.kernel.org,  linux-hardening@vger.kernel.org
Subject: Re: [PATCH] vmcore: replace strncpy with strtomem
Date: Thu, 28 Mar 2024 13:42:15 -0700	[thread overview]
Message-ID: <CAFhGd8pU-utbgHhU5s_20pC_aNK7xtsJDbf+Ayg4Dck2K=4kag@mail.gmail.com> (raw)
In-Reply-To: <ZgTMZ1HYheBMDbei@MiWiFi-R3L-srv>

Hi,

On Wed, Mar 27, 2024 at 6:48 PM Baoquan He <bhe@redhat.com> wrote:
> > Mark these buffers as __nonstring and use strtomem_pad.
>
> Thanks.
>
> I didn't build, wondering if '__nonstring' has to be set so that
> strtomem_pad() can be used.

I do not believe marking buffers as __nonstring is strictly a
requirement. However, the documentation from string.h +302 says we
should do it:
/**
 * strtomem_pad - Copy NUL-terminated string to non-NUL-terminated buffer
 *
 * @dest: Pointer of destination character array (marked as __nonstring)
...

and so does [1] ... "mark the destination buffer variable (or
structure member) with the __nonstring attribute..."

FWIW, this builds just fine without the __nonstring attribute but we
should use it :)

>
> Thanks
> Baoquan
>

[1] https://github.com/KSPP/linux/issues/90

Thanks
Justin

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  reply	other threads:[~2024-03-28 20:42 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-27 21:10 [PATCH] vmcore: replace strncpy with strtomem Justin Stitt
2024-03-27 21:10 ` Justin Stitt
2024-03-28  1:48 ` Baoquan He
2024-03-28  1:48   ` Baoquan He
2024-03-28 20:42   ` Justin Stitt [this message]
2024-03-28 20:42     ` Justin Stitt
2024-03-28 22:03 ` Kees Cook
2024-03-28 22:03   ` Kees Cook

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