linux-kernel - Re: [PATCH] [RFC]arm64:Mark __stack_chk_guard as __ro_after

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Message-ID: <YUByVivmmDr4T6Dx@shell.armlinux.org.uk>
Date:   Tue, 14 Sep 2021 10:58:46 +0100
From:   "Russell King (Oracle)" <linux@...linux.org.uk>
To:     Dan Li <ashimida@...ux.alibaba.com>
Cc:     catalin.marinas@....com, will@...nel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] [RFC]arm64:Mark __stack_chk_guard as __ro_after_init

On Tue, Sep 14, 2021 at 05:44:02PM +0800, Dan Li wrote:
> __stack_chk_guard is setup once while init stage and never changed
> after that.
> 
> Although the modification of this variable at runtime will usually
> cause the kernel to crash (so dose the attacker), it should be marked
> as _ro_after_init, and it should not affect performance if it is
> placed in the ro_after_init section.
> 
> This should also be the case on the ARM platform, or am I missing
> something?

I don't see why it can't be - we only write to it in
boot_init_stack_canary(), same as ARM64.

-- 
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