linux-kernel - Re: [PATCH] sys_personality: Add a optional arch hook arch_check_personality() for common sys

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Date:   Thu, 9 Jan 2020 07:54:24 +0100
From:   Dominik Brodowski <linux@...inikbrodowski.net>
To:     Wang ShaoBo <bobo.shaobowang@...wei.com>
Cc:     mark.rutland@....com, hch@...radead.org, cj.chengjian@...wei.com,
        huawei.libin@...wei.com, xiexiuqi@...wei.com,
        yangyingliang@...wei.com, guohanjun@...wei.com, wcohen@...hat.com,
        linux-kernel@...r.kernel.org, mtk.manpages@...il.com,
        wezhang@...hat.com
Subject: Re: [PATCH] sys_personality: Add a optional arch hook
 arch_check_personality() for common sys_personality()

On Thu, Jan 09, 2020 at 09:38:46AM +0800, Wang ShaoBo wrote:
> currently arm64 use __arm64_sys_arm64_personality() as its default
> syscall. But using a normal hook arch_check_personality() can reject
> personality settings for special case of different archs.

Thanks for your patch!

>  SYSCALL_DEFINE1(personality, unsigned int, personality)
>  {
> -	unsigned int old = current->personality;
> +	int check;
>  
> -	if (personality != 0xffffffff)
> -		set_personality(personality);
> +	check = arch_check_personality(personality);
> +	if (check)
> +		return check;
>  
> -	return old;
> +	return ksys_personality(personality);
>  }

Please leave the default check and call to set_personality()
in here and remove the now-unneeded ksys_personality() from
include/linux/syscalls.h

Thanks,
	Dominik