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SubjectRe: [PATCH v3] intel_txt: add support for S3 memory integrity protection within Intel(R) TXT launched kernel
Date
On Wednesday 10 March 2010, Shane Wang wrote:
> <compared with v2, this patch adds a check of array size in tboot.c, and a note
> to specify which c/s of tboot supports this kind of MACing in intel_txt.txt>
>
> v3: Based on a complexity analysis and tradeoff, we moved all MAC'ing into
> tboot.
>
> This patch adds support for S3 memory integrity protection within an Intel(R)
> TXT launched kernel, for all kernel and userspace memory. All RAM used by the
> kernel and userspace, as indicated by memory ranges of type E820_RAM and
> E820_RESERVED_KERN in the e820 table, will be integrity protected.
>
> The MAINTAINERS file is also updated to reflect the maintainers of the
> TXT-related code.
>
> Signed-off-by: Shane Wang <shane.wang@intel.com>
> Signed-off-by: Joseph Cihula <joseph.cihula@intel.com>

Acked-by: Rafael J. Wysocki <rjw@sisk.pl>

> Documentation/intel_txt.txt | 16 +++++++++-------
> MAINTAINERS | 11 +++++++++++
> arch/x86/include/asm/e820.h | 7 ++++++-
> arch/x86/kernel/tboot.c | 20 +++++++++++---------
> 4 files changed, 37 insertions(+), 17 deletions(-)
>
> diff -r d2911aa1461d Documentation/intel_txt.txt
> --- a/Documentation/intel_txt.txt Thu Mar 04 09:37:53 2010 -0500
> +++ b/Documentation/intel_txt.txt Wed Mar 10 08:18:48 2010 -0500
> @@ -161,13 +161,15 @@ o In order to put a system into any of
> has been restored, it will restore the TPM PCRs and then
> transfer control back to the kernel's S3 resume vector.
> In order to preserve system integrity across S3, the kernel
> - provides tboot with a set of memory ranges (kernel
> - code/data/bss, S3 resume code, and AP trampoline) that tboot
> - will calculate a MAC (message authentication code) over and then
> - seal with the TPM. On resume and once the measured environment
> - has been re-established, tboot will re-calculate the MAC and
> - verify it against the sealed value. Tboot's policy determines
> - what happens if the verification fails.
> + provides tboot with a set of memory ranges (RAM and RESERVED_KERN
> + in the e820 table, but not any memory that BIOS might alter over
> + the S3 transition) that tboot will calculate a MAC (message
> + authentication code) over and then seal with the TPM. On resume
> + and once the measured environment has been re-established, tboot
> + will re-calculate the MAC and verify it against the sealed value.
> + Tboot's policy determines what happens if the verification fails.
> + Note that the c/s 194 of tboot which has the new MAC code supports
> + this.
>
> That's pretty much it for TXT support.
>
> diff -r d2911aa1461d MAINTAINERS
> --- a/MAINTAINERS Thu Mar 04 09:37:53 2010 -0500
> +++ b/MAINTAINERS Wed Mar 10 08:18:48 2010 -0500
> @@ -2891,6 +2891,17 @@ F: Documentation/networking/README.ipw22
> F: Documentation/networking/README.ipw2200
> F: drivers/net/wireless/ipw2x00/ipw2200.*
>
> +INTEL(R) TRUSTED EXECUTION TECHNOLOGY (TXT)
> +M: Joseph Cihula <joseph.cihula@intel.com>
> +M: Shane Wang <shane.wang@intel.com>
> +L: tboot-devel@lists.sourceforge.net
> +W: http://tboot.sourceforge.net
> +T: Mercurial http://www.bughost.org/repos.hg/tboot.hg
> +S: Supported
> +F: Documentation/intel_txt.txt
> +F: include/linux/tboot.h
> +F: arch/x86/kernel/tboot.c
> +
> INTEL WIRELESS WIMAX CONNECTION 2400
> M: Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
> M: linux-wimax@intel.com
> diff -r d2911aa1461d arch/x86/include/asm/e820.h
> --- a/arch/x86/include/asm/e820.h Thu Mar 04 09:37:53 2010 -0500
> +++ b/arch/x86/include/asm/e820.h Wed Mar 10 08:18:48 2010 -0500
> @@ -45,7 +45,12 @@
> #define E820_NVS 4
> #define E820_UNUSABLE 5
>
> -/* reserved RAM used by kernel itself */
> +/*
> + * reserved RAM used by kernel itself
> + * if CONFIG_INTEL_TXT is enabled, memory of this type will be
> + * included in the S3 integrity calculation and so should not include
> + * any memory that BIOS might alter over the S3 transition
> + */
> #define E820_RESERVED_KERN 128
>
> #ifndef __ASSEMBLY__
> diff -r d2911aa1461d arch/x86/kernel/tboot.c
> --- a/arch/x86/kernel/tboot.c Thu Mar 04 09:37:53 2010 -0500
> +++ b/arch/x86/kernel/tboot.c Wed Mar 10 08:18:48 2010 -0500
> @@ -130,6 +130,9 @@ static void add_mac_region(phys_addr_t s
> struct tboot_mac_region *mr;
> phys_addr_t end = start + size;
>
> + if (tboot->num_mac_regions >= MAX_TB_MAC_REGIONS)
> + panic("tboot: Too many MAC regions\n");
> +
> if (start && size) {
> mr = &tboot->mac_regions[tboot->num_mac_regions++];
> mr->start = round_down(start, PAGE_SIZE);
> @@ -139,18 +142,17 @@ static void add_mac_region(phys_addr_t s
>
> static void __init tboot_setup_sleep(void)
> {
> + int i;
> +
> tboot->num_mac_regions = 0;
>
> - /* S3 resume code */
> - add_mac_region(acpi_wakeup_address, WAKEUP_SIZE);
> + for (i = 0; i < e820.nr_map; i++) {
> + if ((e820.map[i].type != E820_RAM)
> + && (e820.map[i].type != E820_RESERVED_KERN))
> + continue;
>
> -#ifdef CONFIG_X86_TRAMPOLINE
> - /* AP trampoline code */
> - add_mac_region(virt_to_phys(trampoline_base), TRAMPOLINE_SIZE);
> -#endif
> -
> - /* kernel code + data + bss */
> - add_mac_region(virt_to_phys(_text), _end - _text);
> + add_mac_region(e820.map[i].addr, e820.map[i].size);
> + }
>
> tboot->acpi_sinfo.kernel_s3_resume_vector = acpi_wakeup_address;
> }
>
>



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