linux-kernel - Re: [PATCH v2] x86/realmode: don't leak kernel addresses

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20190326161457.GN1867@zn.tnic>
Date:   Tue, 26 Mar 2019 17:15:29 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Matteo Croce <mcroce@...hat.com>
Cc:     x86@...nel.org, "H . Peter Anvin" <hpa@...or.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] x86/realmode: don't leak kernel addresses

On Sun, Mar 24, 2019 at 08:05:04PM +0100, Matteo Croce wrote:
> Since commit ad67b74d2469d9b8 ("printk: hash addresses printed with %p"),
> at boot "____ptrval____" is printed instead of the trampoline addresses:
> 
>     Base memory trampoline at [(____ptrval____)] 99000 size 24576
> 
> Remove the address from the print as we don't want to leak kernel
> addresses.
> 
> Fixes: ad67b74d2469d9b8 ("printk: hash addresses printed with %p")
> Signed-off-by: Matteo Croce <mcroce@...hat.com>
> ---
>  arch/x86/realmode/init.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
> index d10105825d57..d76a1380ec37 100644
> --- a/arch/x86/realmode/init.c
> +++ b/arch/x86/realmode/init.c
> @@ -20,8 +20,8 @@ void __init set_real_mode_mem(phys_addr_t mem, size_t size)
>  	void *base = __va(mem);
>  
>  	real_mode_header = (struct real_mode_header *) base;
> -	printk(KERN_DEBUG "Base memory trampoline at [%p] %llx size %zu\n",
> -	       base, (unsigned long long)mem, size);
> +	printk(KERN_DEBUG "Base memory trampoline at %llx size %zu\n",
> +	       (unsigned long long)mem, size);

In case this wasn't clear, please remove the whole printk. And don't
forget to CC lkml on your submissions. CCed now.

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.