linux-hardening - Re: [PATCH v2 2/5] kernel: kexec: copy user-array safely

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Date:   Mon, 11 Sep 2023 08:25:50 +0800
From:   Baoquan He <bhe@...hat.com>
To:     Philipp Stanner <pstanner@...hat.com>
Cc:     Kees Cook <keescook@...omium.org>,
        Andy Shevchenko <andy@...nel.org>,
        Eric Biederman <ebiederm@...ssion.com>,
        Christian Brauner <brauner@...nel.org>,
        David Disseldorp <ddiss@...e.de>,
        Luis Chamberlain <mcgrof@...nel.org>,
        Siddh Raman Pant <code@...dh.me>,
        Nick Alcock <nick.alcock@...cle.com>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>, Zack Rusin <zackr@...are.com>,
        VMware Graphics Reviewers 
        <linux-graphics-maintainer@...are.com>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        kexec@...ts.infradead.org, linux-hardening@...r.kernel.org,
        David Airlie <airlied@...hat.com>
Subject: Re: [PATCH v2 2/5] kernel: kexec: copy user-array safely

On 09/08/23 at 09:59pm, Philipp Stanner wrote:
> Currently, there is no overflow-check with memdup_user().
> 
> Use the new function memdup_array_user() instead of memdup_user() for
> duplicating the user-space array safely.
> 
> Suggested-by: David Airlie <airlied@...hat.com>
> Signed-off-by: Philipp Stanner <pstanner@...hat.com>
> ---
>  kernel/kexec.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/kexec.c b/kernel/kexec.c
> index 107f355eac10..8f35a5a42af8 100644
> --- a/kernel/kexec.c
> +++ b/kernel/kexec.c
> @@ -247,7 +247,7 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
>  		((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH_DEFAULT))
>  		return -EINVAL;
>  
> -	ksegments = memdup_user(segments, nr_segments * sizeof(ksegments[0]));
> +	ksegments = memdup_array_user(segments, nr_segments, sizeof(ksegments[0]));

LGTM,

Acked-by: Baoquan He <bhe@...hat.com>

>  	if (IS_ERR(ksegments))
>  		return PTR_ERR(ksegments);
>  
> -- 
> 2.41.0
> 
> 
> _______________________________________________
> kexec mailing list
> kexec@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec
>

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