[PATCH v2] intel_txt: add support for S3 memory integrityprotection within Intel(R) TXT launched kernel

[Wang, Shane]

v2: 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@xxxxxxxxx>
Signed-off-by: Joseph Cihula <joseph.cihula@xxxxxxxxx>

 Documentation/intel_txt.txt |   14 +++++++-------
 MAINTAINERS                 |   11 +++++++++++
 arch/x86/include/asm/e820.h |    7 ++++++-
 arch/x86/kernel/tboot.c     |   17 ++++++++---------
 4 files changed, 32 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	Tue Mar 09 10:40:17 2010 -0500
@@ -161,13 +161,13 @@ 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.
 
 That's pretty much it for TXT support.
 
diff -r d2911aa1461d MAINTAINERS
--- a/MAINTAINERS	Thu Mar 04 09:37:53 2010 -0500
+++ b/MAINTAINERS	Tue Mar 09 10:40:17 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@xxxxxxxxx>
+M:	Shane Wang <shane.wang@xxxxxxxxx>
+L:	tboot-devel@xxxxxxxxxxxxxxxxxxxxx
+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@xxxxxxxxx>
 M:	linux-wimax@xxxxxxxxx
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	Tue Mar 09 10:40:17 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	Tue Mar 09 10:40:17 2010 -0500
@@ -139,18 +139,17 @@ 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;
 }

Attachment: s3_memory_integrity.patch
Description: s3_memory_integrity.patch