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From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Jason Yan <yanaijie@huawei.com>,
	mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org,
	diana.craciun@nxp.com, benh@kernel.crashing.org,
	paulus@samba.org, npiggin@gmail.com, keescook@chromium.org,
	kernel-hardening@lists.openwall.com
Cc: linux-kernel@vger.kernel.org, wangkefeng.wang@huawei.com,
	yebin10@huawei.com, thunder.leizhen@huawei.com,
	jingxiangfeng@huawei.com, fanchengyang@huawei.com
Subject: Re: [RFC PATCH 09/10] powerpc/fsl_booke/kaslr: support nokaslr cmdline parameter
Date: Mon, 29 Jul 2019 13:38:57 +0200
Message-ID: <e31851fd-5032-2787-ea36-c48a7a6ebbe9@c-s.fr> (raw)
In-Reply-To: <20190717080621.40424-10-yanaijie@huawei.com>



Le 17/07/2019 à 10:06, Jason Yan a écrit :
> One may want to disable kaslr when boot, so provide a cmdline parameter
> 'nokaslr' to support this.
> 
> Signed-off-by: Jason Yan <yanaijie@huawei.com>
> Cc: Diana Craciun <diana.craciun@nxp.com>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Christophe Leroy <christophe.leroy@c-s.fr>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Nicholas Piggin <npiggin@gmail.com>
> Cc: Kees Cook <keescook@chromium.org>
> ---
>   arch/powerpc/kernel/kaslr_booke.c | 14 ++++++++++++++
>   1 file changed, 14 insertions(+)
> 
> diff --git a/arch/powerpc/kernel/kaslr_booke.c b/arch/powerpc/kernel/kaslr_booke.c
> index 00339c05879f..e65a5d9d2ff1 100644
> --- a/arch/powerpc/kernel/kaslr_booke.c
> +++ b/arch/powerpc/kernel/kaslr_booke.c
> @@ -373,6 +373,18 @@ static unsigned long __init kaslr_choose_location(void *dt_ptr, phys_addr_t size
>   	return kaslr_offset;
>   }
>   
> +static inline __init bool kaslr_disabled(void)
> +{
> +	char *str;
> +
> +	str = strstr(early_command_line, "nokaslr");

Why using early_command_line instead of boot_command_line ?


> +	if ((str == early_command_line) ||
> +	    (str > early_command_line && *(str - 1) == ' '))

Is that stuff really needed ?

Why not just:

return strstr(early_command_line, "nokaslr") != NULL;

> +		return true;
> +
> +	return false;
> +}


> +
>   /*
>    * To see if we need to relocate the kernel to a random offset
>    * void *dt_ptr - address of the device tree
> @@ -388,6 +400,8 @@ notrace void __init kaslr_early_init(void *dt_ptr, phys_addr_t size)
>   	kernel_sz = (unsigned long)_end - KERNELBASE;
>   
>   	kaslr_get_cmdline(dt_ptr);
> +	if (kaslr_disabled())
> +		return;
>   
>   	offset = kaslr_choose_location(dt_ptr, size, kernel_sz);
>   
> 

Christophe

  reply index

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-17  8:06 [RFC PATCH 00/10] implement KASLR for powerpc/fsl_booke/32 Jason Yan
2019-07-17  8:06 ` [RFC PATCH 01/10] powerpc: unify definition of M_IF_NEEDED Jason Yan
2019-07-29 10:59   ` Christophe Leroy
2019-07-17  8:06 ` [RFC PATCH 02/10] powerpc: move memstart_addr and kernstart_addr to init-common.c Jason Yan
2019-07-29 11:00   ` Christophe Leroy
2019-07-29 14:31   ` Christoph Hellwig
2019-07-30  0:47     ` Jason Yan
2019-07-17  8:06 ` [RFC PATCH 03/10] powerpc: introduce kimage_vaddr to store the kernel base Jason Yan
2019-07-29 11:00   ` Christophe Leroy
2019-07-29 14:32   ` Christoph Hellwig
2019-07-17  8:06 ` [RFC PATCH 04/10] powerpc/fsl_booke/32: introduce create_tlb_entry() helper Jason Yan
2019-07-29 11:05   ` Christophe Leroy
2019-07-29 13:26     ` Jason Yan
2019-07-17  8:06 ` [RFC PATCH 05/10] powerpc/fsl_booke/32: introduce reloc_kernel_entry() helper Jason Yan
2019-07-29 11:08   ` Christophe Leroy
2019-07-29 13:35     ` Jason Yan
2019-07-17  8:06 ` [RFC PATCH 06/10] powerpc/fsl_booke/32: implement KASLR infrastructure Jason Yan
2019-07-29 11:16   ` Christophe Leroy
2019-07-17  8:06 ` [RFC PATCH 07/10] powerpc/fsl_booke/32: randomize the kernel image offset Jason Yan
2019-07-29 11:33   ` Christophe Leroy
2019-07-29 13:53     ` Jason Yan
2019-07-17  8:06 ` [RFC PATCH 08/10] powerpc/fsl_booke/kaslr: clear the original kernel if randomized Jason Yan
2019-07-29 11:19   ` Christophe Leroy
2019-07-29 13:43     ` Jason Yan
2019-07-17  8:06 ` [RFC PATCH 09/10] powerpc/fsl_booke/kaslr: support nokaslr cmdline parameter Jason Yan
2019-07-29 11:38   ` Christophe Leroy [this message]
2019-07-29 14:04     ` Jason Yan
2019-07-17  8:06 ` [RFC PATCH 10/10] powerpc/fsl_booke/kaslr: dump out kernel offset information on panic Jason Yan
2019-07-29 11:43   ` Christophe Leroy
2019-07-29 14:08     ` Jason Yan
2019-07-25  7:16 ` [RFC PATCH 00/10] implement KASLR for powerpc/fsl_booke/32 Jason Yan
2019-07-25 19:58   ` Kees Cook
2019-07-26  7:20     ` Jason Yan
2019-07-26 16:15       ` Kees Cook
2019-07-26  7:04   ` Diana Madalina Craciun
2019-07-26  7:26     ` Jason Yan
2019-07-29 14:30 ` Diana Madalina Craciun

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