From: Yinghai Lu <yinghai@kernel.org>
To: Kees Cook <keescook@chromium.org>
Cc: Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@suse.de>,
Baoquan He <bhe@redhat.com>, Ingo Molnar <mingo@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>, Borislav Petkov <bp@alien8.de>,
Vivek Goyal <vgoyal@redhat.com>,
Andy Lutomirski <luto@kernel.org>,
lasse.collin@tukaani.org,
Andrew Morton <akpm@linux-foundation.org>,
Dave Young <dyoung@redhat.com>,
"kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v7 1/9] x86/KASLR: Initialize mapping_info every time
Date: Mon, 9 May 2016 15:27:21 -0700 [thread overview]
Message-ID: <CAE9FiQXUDYK93Ob39Gg62yVXDcbwViP05oyTSQC3p_Z0RLK0Cg@mail.gmail.com> (raw)
In-Reply-To: <CAE9FiQW6JokFqma2u-HgncN0XLBxtBHL3OqcccA94B3XPvXAzw@mail.gmail.com>
On Mon, May 9, 2016 at 3:23 PM, Yinghai Lu <yinghai@kernel.org> wrote:
> On Mon, May 9, 2016 at 3:01 PM, Yinghai Lu <yinghai@kernel.org> wrote:
>> Still should be assigned once, and should be done in
>> prepare_level4(). --- by may need different name for that ?
>>
>> The exact reason to have assigning in functions.
>>
>> pgt_data address could be changed during kernel relocation.
>> so can not assigned during compiling time.
>
> Something like:
>
> -/*
> - * Mapping information structure passed to kernel_ident_mapping_init().
> - * Since this never changes, there's no reason to repeatedly fill it
> - * in on the stack when calling add_identity_map().
> - */
> -static struct x86_mapping_info mapping_info = {
> - .alloc_pgt_page = alloc_pgt_page,
> - .context = &pgt_data,
> - .pmd_flag = __PAGE_KERNEL_LARGE_EXEC,
> -};
> +static struct x86_mapping_info mapping_info;
>
> /*
> * Adds the specified range to what will become the new identity mappings.
> @@ -110,8 +101,14 @@ void add_identity_map(unsigned long start,
> unsigned long size)
> unsigned long end = start + size;
>
> /* Make sure we have a top level page table ready to use. */
> - if (!level4p)
> + if (!level4p) {
> + /* need to set once during run time */
> + mapping_info.alloc_pgt_page = alloc_pgt_page;
> + mapping_info.context = &pgt_data;
> + mapping_info.pmd_flag = __PAGE_KERNEL_LARGE_EXEC;
> +
> prepare_level4();
> + }
>
> /* Align boundary to 2M. */
> start = round_down(start, PMD_SIZE);
It would be better if Ingo could fold the change to
https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git/patch/?id=3a94707d7a7bb1eb82acae5fbc035247dd1ba8a5
x86/KASLR: Build identity mappings on demand
As it happens to the last commit in tip/x86/boot.
Thanks
Yinghai
next prev parent reply other threads:[~2016-05-09 22:27 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-09 20:22 [PATCH v7 0/9] x86/KASLR: Randomize virtual address separately Kees Cook
2016-05-09 20:22 ` [PATCH v7 1/9] x86/KASLR: Initialize mapping_info every time Kees Cook
2016-05-09 22:01 ` Yinghai Lu
2016-05-09 22:23 ` Yinghai Lu
2016-05-09 22:27 ` Yinghai Lu [this message]
2016-05-09 22:23 ` Kees Cook
2016-05-09 22:28 ` Yinghai Lu
2016-05-10 5:58 ` Ingo Molnar
2016-05-10 11:21 ` Borislav Petkov
2016-05-10 8:40 ` [tip:x86/boot] " tip-bot for Kees Cook
2016-05-09 20:22 ` [PATCH v7 2/9] x86/boot: Add missing file header comments Kees Cook
2016-05-10 8:41 ` [tip:x86/boot] " tip-bot for Kees Cook
2016-05-09 20:22 ` [PATCH v7 3/9] x86/KASLR: Add slot_area to manage random_addr slots Kees Cook
2016-05-10 8:41 ` [tip:x86/boot] x86/KASLR: Add 'struct slot_area' " tip-bot for Baoquan He
2016-05-09 20:22 ` [PATCH v7 4/9] x86/KASLR: Return earliest overlap when avoiding regions Kees Cook
2016-05-10 8:42 ` [tip:x86/boot] " tip-bot for Kees Cook
2016-05-09 20:22 ` [PATCH v7 5/9] x86/KASLR: Add virtual address choosing function Kees Cook
2016-05-10 8:42 ` [tip:x86/boot] " tip-bot for Baoquan He
2016-05-09 20:22 ` [PATCH v7 6/9] x86/KASLR: Clarify purpose of each get_random_long() Kees Cook
2016-05-10 8:42 ` [tip:x86/boot] " tip-bot for Kees Cook
2016-05-09 20:22 ` [PATCH v7 7/9] x86/KASLR: Randomize virtual address separately Kees Cook
2016-05-09 20:22 ` [PATCH v7 8/9] x86/KASLR: Add physical address randomization >4G Kees Cook
2016-05-09 20:22 ` [PATCH v7 9/9] x86/KASLR: Allow randomization below load address Kees Cook
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