linux-kernel - Re: [PATCH 1/3] x86, mm: Include the entire kernel memory map in trampoline

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

Date:	Thu, 04 Oct 2012 14:08:40 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Jan Beulich <jbeulich@...e.com>
CC:	matt@...sole-pimps.org, linux-kernel@...r.kernel.org,
	matt.fleming@...el.com, mingo@...nel.org, x86@...nel.org,
	mjg@...hat.com, linux-efi@...r.kernel.org
Subject: Re: [PATCH 1/3] x86, mm: Include the entire kernel memory map in
 trampoline_pgd

On 10/03/2012 06:31 AM, Jan Beulich wrote:
>>>> Matt Fleming <matt@...sole-pimps.org> 10/03/12 2:59 PM >>>
>> +static int insert_identity_mapping(resource_size_t paddr, unsigned long vaddr,
>> +                    unsigned long size)
>> +{
>> +    unsigned long end = vaddr + size;
>> +    unsigned long next;
>> +    pgd_t *vpgd, *ppgd;
>> +
>> +#ifdef CONFIG_X86_32
>> +    ppgd = initial_page_table + pgd_index(paddr);
>> +
>> +    if (paddr >= PAGE_OFFSET || paddr + size > PAGE_OFFSET)
>> +        return 1;
>> +#else
>> +    ppgd = __va(real_mode_header->trampoline_pgd) + pgd_index(paddr);
>
> Missing equivalent code (to the 32-bit one above) here - after all, you're trying
> to potentially insert a 52-bit physical address into 48-bit virtual space.
>

We should have the check, but at least for Linux support we require
P <= V-2.

	-hpa


-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/