From: Kees Cook <keescook@chromium.org>
To: Yinghai Lu <yinghai@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>, Baoquan He <bhe@redhat.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 40/42] x86, 64bit: remove highmap for not needed ranges
Date: Tue, 7 Jul 2015 16:17:15 -0700 [thread overview]
Message-ID: <CAGXu5j+mat7kg0bpBvvCDg8k=vASHtAd7r2GhEEXeY_Cn_huog@mail.gmail.com> (raw)
In-Reply-To: <1436300428-21163-41-git-send-email-yinghai@kernel.org>
On Tue, Jul 7, 2015 at 1:20 PM, Yinghai Lu <yinghai@kernel.org> wrote:
> add cleanup_highmap_late to remove highmap for initmem, around rodata, and
> [_brk_end, all_end).
>
> Kernel Layout:
>
> [ 0.000000] .text: [0x01000000-0x0200df88]
> [ 0.000000] .rodata: [0x02200000-0x02a1dfff]
> [ 0.000000] .data: [0x02c00000-0x02e510ff]
> [ 0.000000] .init: [0x02e53000-0x03213fff]
> [ 0.000000] .bss: [0x03222000-0x0437cfff]
> [ 0.000000] .brk: [0x0437d000-0x043a2fff]
>
> Actually used brk:
> [ 0.270365] memblock_reserve: [0x0000000437d000-0x00000004383fff] flags 0x0 BRK
>
> Before patch:
> ---[ High Kernel Mapping ]---
> 0xffffffff80000000-0xffffffff81000000 16M pmd
> 0xffffffff81000000-0xffffffff82000000 16M ro PSE GLB x pmd
> 0xffffffff82000000-0xffffffff82011000 68K ro GLB x pte
> 0xffffffff82011000-0xffffffff82200000 1980K RW GLB x pte
What change introduced this RW + x area? I don't see any of those
currently in my page tables.
-Kees
> 0xffffffff82200000-0xffffffff82a00000 8M ro PSE GLB NX pmd
> 0xffffffff82a00000-0xffffffff82a1e000 120K ro GLB NX pte
> 0xffffffff82a1e000-0xffffffff82c00000 1928K RW GLB NX pte
> 0xffffffff82c00000-0xffffffff82e00000 2M RW PSE GLB NX pmd
> 0xffffffff82e00000-0xffffffff83000000 2M RW GLB NX pte
> 0xffffffff83000000-0xffffffff83200000 2M RW PSE GLB NX pmd
> 0xffffffff83200000-0xffffffff83400000 2M RW GLB NX pte
> 0xffffffff83400000-0xffffffff84400000 16M RW PSE GLB NX pmd
> 0xffffffff84400000-0xffffffffa0000000 444M pmd
>
> After patch:
> ---[ High Kernel Mapping ]---
> 0xffffffff80000000-0xffffffff81000000 16M pmd
> 0xffffffff81000000-0xffffffff82000000 16M ro PSE GLB x pmd
> 0xffffffff82000000-0xffffffff82012000 72K ro GLB x pte
> 0xffffffff82012000-0xffffffff82200000 1976K pte
> 0xffffffff82200000-0xffffffff82a00000 8M ro PSE GLB NX pmd
> 0xffffffff82a00000-0xffffffff82a1e000 120K ro GLB NX pte
> 0xffffffff82a1e000-0xffffffff82c00000 1928K pte
> 0xffffffff82c00000-0xffffffff82e00000 2M RW PSE GLB NX pmd
> 0xffffffff82e00000-0xffffffff82e53000 332K RW GLB NX pte
> 0xffffffff82e53000-0xffffffff83000000 1716K pte
> 0xffffffff83000000-0xffffffff83200000 2M pmd
> 0xffffffff83200000-0xffffffff83214000 80K pte
> 0xffffffff83214000-0xffffffff83400000 1968K RW GLB NX pte
> 0xffffffff83400000-0xffffffff84200000 14M RW PSE GLB NX pmd
> 0xffffffff84200000-0xffffffff84384000 1552K RW GLB NX pte
> 0xffffffff84384000-0xffffffff84400000 496K pte
> 0xffffffff84400000-0xffffffffa0000000 444M pmd
>
> So remove some range around rodata.
>
> -v4: adapt it to all_end change.
>
> Signed-off-by: Yinghai Lu <yinghai@kernel.org>
> ---
> arch/x86/mm/init_64.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 62 insertions(+)
>
> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
> index 2507b98..38aa59c 100644
> --- a/arch/x86/mm/init_64.c
> +++ b/arch/x86/mm/init_64.c
> @@ -1010,6 +1010,61 @@ void __init mem_init(void)
> }
>
> #ifdef CONFIG_DEBUG_RODATA
> +static void remove_highmap_2m(unsigned long addr)
> +{
> + pgd_t *pgd = pgd_offset_k(addr);
> + pud_t *pud = (pud_t *)pgd_page_vaddr(*pgd) + pud_index(addr);
> + pmd_t *pmd = (pmd_t *)pud_page_vaddr(*pud) + pmd_index(addr);
> +
> + set_pmd(pmd, __pmd(0));
> +}
> +
> +static void remove_highmap_2m_partial(unsigned long addr, unsigned long end)
> +{
> + int i;
> + pgd_t *pgd = pgd_offset_k(addr);
> + pud_t *pud = (pud_t *)pgd_page_vaddr(*pgd) + pud_index(addr);
> + pmd_t *pmd = (pmd_t *)pud_page_vaddr(*pud) + pmd_index(addr);
> + pte_t *pte = (pte_t *)pmd_page_vaddr(*pmd) + pte_index(addr);
> +
> + for (i = pte_index(addr); i < pte_index(end - 1) + 1; i++, pte++)
> + set_pte(pte, __pte(0));
> +}
> +
> +static void cleanup_highmap_late(unsigned long start, unsigned long end)
> +{
> + unsigned long addr;
> + unsigned long start_2m_aligned = roundup(start, PMD_SIZE);
> + unsigned long end_2m_aligned = rounddown(end, PMD_SIZE);
> +
> + start = PFN_ALIGN(start);
> + end &= PAGE_MASK;
> +
> + if (start >= end)
> + return;
> +
> + if (start < start_2m_aligned) {
> + unsigned long tmp = min(start_2m_aligned, end);
> +
> + set_memory_4k(start, (tmp - start) >> PAGE_SHIFT);
> + remove_highmap_2m_partial(start, tmp);
> + }
> +
> + for (addr = start_2m_aligned; addr < end_2m_aligned; addr += PMD_SIZE)
> + remove_highmap_2m(addr);
> +
> + if (start <= end_2m_aligned && end_2m_aligned < end) {
> + set_memory_4k(end_2m_aligned,
> + (end - end_2m_aligned) >> PAGE_SHIFT);
> + remove_highmap_2m_partial(end_2m_aligned, end);
> + }
> +
> + subtract_range(pfn_highmapped, NR_RANGE,
> + __pa_symbol(start) >> PAGE_SHIFT,
> + __pa_symbol(end) >> PAGE_SHIFT);
> + nr_pfn_highmapped = clean_sort_range(pfn_highmapped, NR_RANGE);
> +}
> +
> const int rodata_test_data = 0xC3;
> EXPORT_SYMBOL_GPL(rodata_test_data);
>
> @@ -1058,6 +1113,7 @@ void mark_rodata_ro(void)
> unsigned long end = (unsigned long) &__end_rodata_hpage_align;
> unsigned long text_end = PFN_ALIGN(&__stop___ex_table);
> unsigned long rodata_end = PFN_ALIGN(&__end_rodata);
> + unsigned long data_start = PFN_ALIGN(&_sdata);
> unsigned long all_end;
>
> printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
> @@ -1081,6 +1137,12 @@ void mark_rodata_ro(void)
> all_end = roundup(_brk_end, PMD_SIZE);
> set_memory_nx(rodata_start, (all_end - rodata_start) >> PAGE_SHIFT);
>
> + cleanup_highmap_late(text_end, rodata_start);
> + cleanup_highmap_late(rodata_end, data_start);
> + cleanup_highmap_late(PFN_ALIGN(_brk_end), all_end);
> + cleanup_highmap_late((unsigned long)(&__init_begin),
> + (unsigned long)(&__init_end));
> +
> rodata_test();
>
> #ifdef CONFIG_CPA_DEBUG
> --
> 1.8.4.5
>
> --
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--
Kees Cook
Chrome OS Security
next prev parent reply other threads:[~2015-07-07 23:17 UTC|newest]
Thread overview: 79+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-07 20:19 [PATCH 00/42] x86: updated patches for kaslr and setup_data etc for v4.3 Yinghai Lu
2015-07-07 20:19 ` [PATCH 01/42] x86, kasl: Remove not needed parameter for choose_kernel_location Yinghai Lu
2015-07-07 20:57 ` Kees Cook
2015-07-07 20:19 ` [PATCH 02/42] x86, boot: Move compressed kernel to end of buffer before decompressing Yinghai Lu
2015-07-07 21:22 ` Kees Cook
2015-07-07 20:19 ` [PATCH 03/42] x86, boot: Fix run_size calculation Yinghai Lu
2015-07-07 22:15 ` Kees Cook
2015-07-07 20:19 ` [PATCH 04/42] x86, kaslr: Kill not needed and wrong run_size calculation code Yinghai Lu
2015-07-07 22:18 ` Kees Cook
2015-07-07 20:19 ` [PATCH 05/42] x86, kaslr: rename output_size to output_run_size Yinghai Lu
2015-07-07 20:19 ` [PATCH 06/42] x86, kaslr: Consolidate mem_avoid array filling Yinghai Lu
2015-07-07 22:36 ` Kees Cook
2015-07-07 20:19 ` [PATCH 07/42] x86, boot: Move z_extract_offset calculation to header.S Yinghai Lu
2015-07-07 20:19 ` [PATCH 08/42] x86, kaslr: Get correct max_addr for relocs pointer Yinghai Lu
2015-07-07 22:40 ` Kees Cook
2015-07-07 20:19 ` [PATCH 09/42] x86, boot: Split kernel_ident_mapping_init to another file Yinghai Lu
2015-07-07 20:19 ` [PATCH 10/42] x86, 64bit: Set ident_mapping for kaslr Yinghai Lu
2015-07-07 20:19 ` [PATCH 11/42] x86, boot: Add checking for memcpy Yinghai Lu
2015-07-07 20:19 ` [PATCH 12/42] x86, kaslr: Fix a bug that relocation can not be handled when kernel is loaded above 2G Yinghai Lu
2015-07-07 22:42 ` Kees Cook
2015-07-07 20:19 ` [PATCH 13/42] x86, kaslr: Introduce struct slot_area to manage randomization slot info Yinghai Lu
2015-07-07 20:20 ` [PATCH 14/42] x86, kaslr: Add two functions which will be used later Yinghai Lu
2015-07-07 20:20 ` [PATCH 15/42] x86, kaslr: Introduce fetch_random_virt_offset to randomize the kernel text mapping address Yinghai Lu
2015-07-07 20:20 ` [PATCH 16/42] x86, kaslr: Randomize physical and virtual address of kernel separately Yinghai Lu
2015-07-07 20:20 ` [PATCH 17/42] x86, kaslr: Add support of kernel physical address randomization above 4G Yinghai Lu
2015-07-07 20:20 ` [PATCH 18/42] x86, kaslr: Remove useless codes Yinghai Lu
2015-07-07 20:20 ` [PATCH 19/42] x86, kaslr: Allow random address could be below loaded address Yinghai Lu
2015-07-07 20:20 ` [PATCH 20/42] x86, boot: Add printf support for early console in compressed/misc.c Yinghai Lu
2015-07-07 20:20 ` [PATCH 21/42] x86, boot: Add more debug printout " Yinghai Lu
2015-07-07 20:20 ` [PATCH 22/42] x86, setup: Check early serial console per string instead of one char Yinghai Lu
2015-07-07 22:59 ` Kees Cook
2015-07-07 20:20 ` [PATCH 23/42] x86, setup: Use puts() instead of printf() in edd code Yinghai Lu
2015-07-07 20:20 ` [PATCH 24/42] x86: Setup early console as early as possible in x86_start_kernel() Yinghai Lu
2015-07-07 20:20 ` [PATCH 25/42] x86, boot: print compression suffix in decompress stage Yinghai Lu
2015-07-07 23:13 ` Kees Cook
2015-07-07 20:20 ` [PATCH 26/42] x86: remove not needed clear_page calling Yinghai Lu
2015-07-07 23:14 ` Kees Cook
2015-07-07 20:20 ` [PATCH 27/42] x86: restore end_of_ram to E820_RAM Yinghai Lu
2015-07-08 17:44 ` Matt Fleming
2015-07-09 1:41 ` Dan Williams
2015-07-09 7:45 ` Christoph Hellwig
2015-07-09 11:17 ` Matt Fleming
2015-07-07 20:20 ` [PATCH 28/42] x86, boot: Allow 64bit EFI kernel to be loaded above 4G Yinghai Lu
2015-07-07 23:12 ` Kees Cook
2015-07-08 18:00 ` Matt Fleming
2015-07-07 20:20 ` [PATCH 29/42] x86: Find correct 64 bit ramdisk address for microcode early update Yinghai Lu
2015-07-07 23:08 ` Kees Cook
2015-07-07 20:20 ` [PATCH 30/42] x86: Kill E820_RESERVED_KERN Yinghai Lu
2015-07-07 20:20 ` [PATCH 31/42] x86, efi: Copy SETUP_EFI data and access directly Yinghai Lu
2015-07-22 10:58 ` Matt Fleming
2015-07-22 10:58 ` Matt Fleming
2015-07-24 2:07 ` Dave Young
2015-07-24 2:07 ` Dave Young
2015-07-07 20:20 ` [PATCH 32/42] x86, of: Let add_dtb reserve setup_data locally Yinghai Lu
2015-07-07 20:20 ` [PATCH 33/42] x86, boot: Add add_pci handler for SETUP_PCI Yinghai Lu
2015-07-14 22:30 ` Bjorn Helgaas
2015-07-07 20:20 ` [PATCH 34/42] x86: Kill not used setup_data handling code Yinghai Lu
2015-07-07 20:20 ` [PATCH 35/42] x86, boot, PCI: Convert SETUP_PCI data to list Yinghai Lu
2015-07-14 22:35 ` Bjorn Helgaas
2015-07-15 1:57 ` Yinghai Lu
2015-07-07 20:20 ` [PATCH 36/42] x86, boot, PCI: Copy SETUP_PCI rom to kernel space Yinghai Lu
2015-07-07 20:20 ` [PATCH 37/42] x86, boot, PCI: Export SETUP_PCI data via sysfs Yinghai Lu
2015-07-07 20:20 ` [PATCH 38/42] x86: Fix typo in mark_rodata_ro Yinghai Lu
2015-07-07 23:05 ` Kees Cook
2015-07-07 20:20 ` [PATCH 39/42] x86, 64bit: add pfn_range_is_highmapped() Yinghai Lu
2015-07-07 20:20 ` [PATCH 40/42] x86, 64bit: remove highmap for not needed ranges Yinghai Lu
2015-07-07 23:17 ` Kees Cook [this message]
2015-07-07 20:20 ` [PATCH 41/42] x86, 64bit: Add __pa_high/__va_high Yinghai Lu
2015-07-07 20:20 ` [PATCH 42/42] x86: fix msr print again Yinghai Lu
2015-07-07 23:21 ` [PATCH 00/42] x86: updated patches for kaslr and setup_data etc for v4.3 Kees Cook
2015-10-02 20:16 ` Kees Cook
2016-02-06 11:50 ` Baoquan He
2016-02-09 4:31 ` Kees Cook
2016-02-09 4:31 ` [kernel-hardening] " Kees Cook
2016-02-15 7:29 ` Baoquan He
2016-02-15 7:29 ` [kernel-hardening] " Baoquan He
2016-02-16 23:50 ` Kees Cook
2016-02-16 23:50 ` [kernel-hardening] " Kees Cook
2015-07-08 10:51 ` Ingo Molnar
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