linux-kernel - Re: [PATCH] ARM: mvebu: declare asm symbols as character arrays in pmsu.c

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Date:   Wed, 27 Jun 2018 08:20:37 +0200
From:   Gregory CLEMENT <gregory.clement@...tlin.com>
To:     Ethan Tuttle <ethan@...antuttle.com>
Cc:     Andrew Lunn <andrew@...n.ch>, Jason Cooper <jason@...edaemon.net>,
        Russell King <linux@...linux.org.uk>,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>
Subject: Re: [PATCH] ARM: mvebu: declare asm symbols as character arrays in pmsu.c

Hi Ethan,

 On mar., juin 19 2018, Ethan Tuttle <ethan@...antuttle.com> wrote:

> With CONFIG_FORTIFY_SOURCE, memcpy uses the declared size of operands to
> detect buffer overflows.  If src or dest is declared as a char, attempts to
> copy more than byte will result in a fortify_panic().
>
> Address this problem in mvebu_setup_boot_addr_wa() by declaring
> mvebu_boot_wa_start and mvebu_boot_wa_end as character arrays.  Also remove
> a couple addressof operators to avoid "arithmetic on pointer to an
> incomplete type" compiler error.
>
> See commit 54a7d50b9205 ("x86: mark kprobe templates as character arrays,
> not single characters") for a similar fix.
>
> Fixes "detected buffer overflow in memcpy" error during init on some mvebu
> systems (armada-370-xp, armada-375):
>
> (fortify_panic) from (mvebu_setup_boot_addr_wa+0xb0/0xb4)
> (mvebu_setup_boot_addr_wa) from (mvebu_v7_cpu_pm_init+0x154/0x204)
> (mvebu_v7_cpu_pm_init) from (do_one_initcall+0x7c/0x1a8)
> (do_one_initcall) from (kernel_init_freeable+0x1bc/0x254)
> (kernel_init_freeable) from (kernel_init+0x8/0x114)
> (kernel_init) from (ret_from_fork+0x14/0x2c)
>
> Signed-off-by: Ethan Tuttle <ethan@...antuttle.com>
> Tested-by: Ethan Tuttle <ethan@...antuttle.com>

Out of curiosity on which platform did you test it?

Applied on mvebu/arm

Thanks,

Gregory

> ---
>  arch/arm/mach-mvebu/pmsu.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm/mach-mvebu/pmsu.c b/arch/arm/mach-mvebu/pmsu.c
> index 27a78c80e5b1..73d5d72dfc3e 100644
> --- a/arch/arm/mach-mvebu/pmsu.c
> +++ b/arch/arm/mach-mvebu/pmsu.c
> @@ -116,8 +116,8 @@ void mvebu_pmsu_set_cpu_boot_addr(int hw_cpu, void *boot_addr)
>  		PMSU_BOOT_ADDR_REDIRECT_OFFSET(hw_cpu));
>  }
>  
> -extern unsigned char mvebu_boot_wa_start;
> -extern unsigned char mvebu_boot_wa_end;
> +extern unsigned char mvebu_boot_wa_start[];
> +extern unsigned char mvebu_boot_wa_end[];
>  
>  /*
>   * This function sets up the boot address workaround needed for SMP
> @@ -130,7 +130,7 @@ int mvebu_setup_boot_addr_wa(unsigned int crypto_eng_target,
>  			     phys_addr_t resume_addr_reg)
>  {
>  	void __iomem *sram_virt_base;
> -	u32 code_len = &mvebu_boot_wa_end - &mvebu_boot_wa_start;
> +	u32 code_len = mvebu_boot_wa_end - mvebu_boot_wa_start;
>  
>  	mvebu_mbus_del_window(BOOTROM_BASE, BOOTROM_SIZE);
>  	mvebu_mbus_add_window_by_id(crypto_eng_target, crypto_eng_attribute,
> -- 
> 2.17.1
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

-- 
Gregory Clement, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
http://bootlin.com

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