vboot2: Add support for kernel version secure data space

Holds kernel rollback information.  Will be used by vboot 2.0 kernel
verification.

BUG=chromium:487699
BRANCH=none
TEST=make -j runtests

Change-Id: Ib4a70e943ebd79aac06404df09cf4ce62d719201
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/270626
Reviewed-by: Bill Richardson <wfrichar@chromium.org>

7 files changed, 414 insertions, 8 deletions

diff --git a/Makefile b/Makefile
index 00c6085c..aa82aa2a 100644
--- a/Makefile
+++ b/Makefile
@@ -330,6 +330,7 @@ FWLIB2X_SRCS = \
 	firmware/2lib/2nvstorage.c \
 	firmware/2lib/2rsa.c \
 	firmware/2lib/2secdata.c \
+	firmware/2lib/2secdatak.c \
 	firmware/2lib/2sha1.c \
 	firmware/2lib/2sha256.c \
 	firmware/2lib/2sha512.c \
@@ -711,6 +712,7 @@ TEST2X_NAMES = \
 	tests/vb2_nvstorage_tests \
 	tests/vb2_rsa_utility_tests \
 	tests/vb2_secdata_tests \
+	tests/vb2_secdatak_tests \
 	tests/vb2_sha_tests
 
 TEST20_NAMES = \
@@ -1376,6 +1378,7 @@ run2tests: test_setup
 	${RUNTEST} ${BUILD_RUN}/tests/vb2_nvstorage_tests
 	${RUNTEST} ${BUILD_RUN}/tests/vb2_rsa_utility_tests
 	${RUNTEST} ${BUILD_RUN}/tests/vb2_secdata_tests
+	${RUNTEST} ${BUILD_RUN}/tests/vb2_secdatak_tests
 	${RUNTEST} ${BUILD_RUN}/tests/vb2_sha_tests
 	${RUNTEST} ${BUILD_RUN}/tests/vb20_api_tests
 	${RUNTEST} ${BUILD_RUN}/tests/vb20_common_tests
diff --git a/firmware/2lib/2secdatak.c b/firmware/2lib/2secdatak.c
new file mode 100644
index 00000000..af11aef4
--- /dev/null
+++ b/firmware/2lib/2secdatak.c
@@ -0,0 +1,112 @@
+/* Copyright 2015 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * Secure storage APIs - kernel version space
+ */
+
+#include "2sysincludes.h"
+#include "2common.h"
+#include "2crc8.h"
+#include "2misc.h"
+#include "2secdata.h"
+
+int vb2_secdatak_check_crc(const struct vb2_context *ctx)
+{
+	const struct vb2_secdatak *sec =
+		(const struct vb2_secdatak *)ctx->secdatak;
+
+	/* Verify CRC */
+	if (sec->crc8 != vb2_crc8(sec, offsetof(struct vb2_secdatak, crc8)))
+		return VB2_ERROR_SECDATAK_CRC;
+
+	return VB2_SUCCESS;
+}
+
+int vb2_secdatak_create(struct vb2_context *ctx)
+{
+	struct vb2_secdatak *sec = (struct vb2_secdatak *)ctx->secdatak;
+
+	/* Clear the entire struct */
+	memset(sec, 0, sizeof(*sec));
+
+	/* Set to current version */
+	sec->struct_version = VB2_SECDATAK_VERSION;
+
+	/* Set UID */
+	sec->uid = VB2_SECDATAK_UID;
+
+	/* Calculate initial CRC */
+	sec->crc8 = vb2_crc8(sec, offsetof(struct vb2_secdatak, crc8));
+	ctx->flags |= VB2_CONTEXT_SECDATAK_CHANGED;
+	return VB2_SUCCESS;
+}
+
+int vb2_secdatak_init(struct vb2_context *ctx)
+{
+	struct vb2_secdatak *sec = (struct vb2_secdatak *)ctx->secdatak;
+	struct vb2_shared_data *sd = vb2_get_sd(ctx);
+	int rv;
+
+	rv = vb2_secdatak_check_crc(ctx);
+	if (rv)
+		return rv;
+
+	/* Make sure the UID is correct */
+	if (sec->uid != VB2_SECDATAK_UID)
+		return VB2_ERROR_SECDATAK_UID;
+
+	/* Set status flag */
+	sd->status |= VB2_SD_STATUS_SECDATAK_INIT;
+	/* TODO: unit test for that */
+
+	return VB2_SUCCESS;
+}
+
+int vb2_secdatak_get(struct vb2_context *ctx,
+		    enum vb2_secdatak_param param,
+		    uint32_t *dest)
+{
+	struct vb2_secdatak *sec = (struct vb2_secdatak *)ctx->secdatak;
+
+	if (!(vb2_get_sd(ctx)->status & VB2_SD_STATUS_SECDATAK_INIT))
+		return VB2_ERROR_SECDATAK_GET_UNINITIALIZED;
+
+	switch(param) {
+	case VB2_SECDATAK_VERSIONS:
+		*dest = sec->kernel_versions;
+		return VB2_SUCCESS;
+
+	default:
+		return VB2_ERROR_SECDATAK_GET_PARAM;
+	}
+}
+
+int vb2_secdatak_set(struct vb2_context *ctx,
+		    enum vb2_secdatak_param param,
+		    uint32_t value)
+{
+	struct vb2_secdatak *sec = (struct vb2_secdatak *)ctx->secdatak;
+	uint32_t now;
+
+	if (!(vb2_get_sd(ctx)->status & VB2_SD_STATUS_SECDATAK_INIT))
+		return VB2_ERROR_SECDATAK_SET_UNINITIALIZED;
+
+	/* If not changing the value, don't regenerate the CRC. */
+	if (vb2_secdatak_get(ctx, param, &now) == VB2_SUCCESS && now == value)
+		return VB2_SUCCESS;
+
+	switch(param) {
+	case VB2_SECDATAK_VERSIONS:
+		sec->kernel_versions = value;
+		break;
+
+	default:
+		return VB2_ERROR_SECDATAK_SET_PARAM;
+	}
+
+	/* Regenerate CRC */
+	sec->crc8 = vb2_crc8(sec, offsetof(struct vb2_secdatak, crc8));
+	ctx->flags |= VB2_CONTEXT_SECDATAK_CHANGED;
+	return VB2_SUCCESS;
+}
diff --git a/firmware/2lib/include/2api.h b/firmware/2lib/include/2api.h
index d8cc9b8c..0b436842 100644
--- a/firmware/2lib/include/2api.h
+++ b/firmware/2lib/include/2api.h
@@ -31,8 +31,9 @@
 /* Size of non-volatile data used by vboot */
 #define VB2_NVDATA_SIZE 16
 
-/* Size of secure data used by vboot */
+/* Size of secure data spaces used by vboot */
 #define VB2_SECDATA_SIZE 10
+#define VB2_SECDATAK_SIZE 14
 
 /*
  * Recommended size of work buffer.
@@ -93,6 +94,12 @@ enum vb2_context_flags {
 
 	/* Erase TPM developer mode state if it is enabled. */
 	VB2_DISABLE_DEVELOPER_MODE = (1 << 9),
+
+	/*
+	 * Verified boot has changed secdatak[].  Caller must save secdatak[]
+	 * back to its underlying storage, then may clear this flag.
+	 */
+	VB2_CONTEXT_SECDATAK_CHANGED = (1 << 11),
 };
 
 /*
@@ -128,10 +135,11 @@ struct vb2_context {
 	uint8_t nvdata[VB2_NVDATA_SIZE];
 
 	/*
-	 * Secure data.  Caller must fill this from some secure non-volatile
-	 * location.  If the VB2_CONTEXT_SECDATA_CHANGED flag is set when a
-	 * function returns, caller must save the data back to the secure
-	 * non-volatile location and then clear the flag.
+	 * Secure data for firmware verification stage.  Caller must fill this
+	 * from some secure non-volatile location.  If the
+	 * VB2_CONTEXT_SECDATA_CHANGED flag is set when a function returns,
+	 * caller must save the data back to the secure non-volatile location
+	 * and then clear the flag.
 	 */
 	uint8_t secdata[VB2_SECDATA_SIZE];
 
@@ -154,6 +162,19 @@ struct vb2_context {
 	 * copied when relocating the work buffer.
 	 */
 	uint32_t workbuf_used;
+
+	/**********************************************************************
+	 * Fields caller must initialize before calling vb2api_kernel_phase1().
+	 */
+
+	/*
+	 * Secure data for kernel verification stage.  Caller must fill this
+	 * from some secure non-volatile location.  If the
+	 * VB2_CONTEXT_SECDATAK_CHANGED flag is set when a function returns,
+	 * caller must save the data back to the secure non-volatile location
+	 * and then clear the flag.
+	 */
+	uint8_t secdatak[VB2_SECDATAK_SIZE];
 };
 
 enum vb2_resource_index {
@@ -234,8 +255,7 @@ enum vb2_pcr_digest {
  *
  * At this point, firmware verification is done, and vb2_context contains the
  * kernel key needed to verify the kernel.  That context should be preserved
- * and passed on to kernel selection.  For now, that requires translating it
- * into the old VbSharedData format (via a func which does not yet exist...)
+ * and passed on to kernel selection.
  */
 
 /**
@@ -267,6 +287,34 @@ int vb2api_secdata_check(const struct vb2_context *ctx);
 int vb2api_secdata_create(struct vb2_context *ctx);
 
 /**
+ * Sanity-check the contents of the kernel version secure storage context.
+ *
+ * Use this if reading from secure storage may be flaky, and you want to retry
+ * reading it several times.
+ *
+ * This may be called before vb2api_phase1().
+ *
+ * @param ctx		Context pointer
+ * @return VB2_SUCCESS, or non-zero error code if error.
+ */
+int vb2api_secdatak_check(const struct vb2_context *ctx);
+
+/**
+ * Create fresh data in the kernel version secure storage context.
+ *
+ * Use this only when initializing the secure storage context on a new machine
+ * the first time it boots.  Do NOT simply use this if vb2api_secdatak_check()
+ * (or any other API in this library) fails; that could allow the secure data
+ * to be rolled back to an insecure state.
+ *
+ * This may be called before vb2api_phase1().
+ *
+ * @param ctx		Context pointer
+ * @return VB2_SUCCESS, or non-zero error code if error.
+ */
+int vb2api_secdatak_create(struct vb2_context *ctx);
+
+/**
  * Report firmware failure to vboot.
  *
  * This may be called before vb2api_phase1() to indicate errors in the boot
diff --git a/firmware/2lib/include/2return_codes.h b/firmware/2lib/include/2return_codes.h
index 20a7947c..cd8cc270 100644
--- a/firmware/2lib/include/2return_codes.h
+++ b/firmware/2lib/include/2return_codes.h
@@ -111,6 +111,30 @@ enum vb2_return_code {
 	/* Called vb2_secdata_set() with uninitialized secdata */
 	VB2_ERROR_SECDATA_SET_UNINITIALIZED,
 
+	/* Bad CRC in vb2_secdatak_check_crc() */
+	VB2_ERROR_SECDATAK_CRC,
+
+	/* Bad struct version in vb2_secdatak_init() */
+	VB2_ERROR_SECDATAK_VERSION,
+
+	/* Bad uid in vb2_secdatak_init() */
+	VB2_ERROR_SECDATAK_UID,
+
+	/* Invalid param in vb2_secdatak_get() */
+	VB2_ERROR_SECDATAK_GET_PARAM,
+
+	/* Invalid param in vb2_secdatak_set() */
+	VB2_ERROR_SECDATAK_SET_PARAM,
+
+	/* Invalid flags passed to vb2_secdatak_set() */
+	VB2_ERROR_SECDATAK_SET_FLAGS,
+
+	/* Called vb2_secdatak_get() with uninitialized secdatak */
+	VB2_ERROR_SECDATAK_GET_UNINITIALIZED,
+
+	/* Called vb2_secdatak_set() with uninitialized secdatak */
+	VB2_ERROR_SECDATAK_SET_UNINITIALIZED,
+
         /**********************************************************************
 	 * Common code errors
 	 */
diff --git a/firmware/2lib/include/2secdata.h b/firmware/2lib/include/2secdata.h
index 25a051d9..d27432e8 100644
--- a/firmware/2lib/include/2secdata.h
+++ b/firmware/2lib/include/2secdata.h
@@ -8,6 +8,9 @@
 #ifndef VBOOT_REFERENCE_VBOOT_SECDATA_H_
 #define VBOOT_REFERENCE_VBOOT_SECDATA_H_
 
+/*****************************************************************************/
+/* Firmware version space */
+
 /* Expected value of vb2_secdata.version */
 #define VB2_SECDATA_VERSION 2
 
@@ -28,7 +31,7 @@ enum vb2_secdata_flags {
 	VB2_SECDATA_FLAG_DEV_MODE = (1 << 1),
 };
 
-/* Secure data area */
+/* Secure data area (firmware space) */
 struct vb2_secdata {
 	/* Struct version, for backwards compatibility */
 	uint8_t struct_version;
@@ -55,6 +58,39 @@ enum vb2_secdata_param {
 	VB2_SECDATA_VERSIONS,
 };
 
+/*****************************************************************************/
+/* Kernel version space */
+
+/* Kernel space - KERNEL_NV_INDEX, locked with physical presence. */
+#define VB2_SECDATAK_VERSION 2
+#define VB2_SECDATAK_UID 0x4752574c  /* 'GRWL' */
+
+struct vb2_secdatak {
+	/* Struct version, for backwards compatibility */
+	uint8_t struct_version;
+
+	/* Unique ID to detect space redefinition */
+	uint32_t uid;
+
+	/* Kernel versions */
+	uint32_t kernel_versions;
+
+	/* Reserved for future expansion */
+	uint8_t reserved[3];
+
+	/* CRC; must be last field in struct */
+	uint8_t crc8;
+} __attribute__((packed));
+
+/* Which param to get/set for vb2_secdatak_get() / vb2_secdatak_set() */
+enum vb2_secdatak_param {
+	/* Kernel versions */
+	VB2_SECDATAK_VERSIONS = 0,
+};
+
+/*****************************************************************************/
+/* Firmware version space functions */
+
 /**
  * Check the CRC of the secure storage context.
  *
@@ -114,4 +150,70 @@ int vb2_secdata_set(struct vb2_context *ctx,
 		    enum vb2_secdata_param param,
 		    uint32_t value);
 
+/*****************************************************************************/
+/* Kernel version space functions.
+ *
+ * These are separate functions so that they don't bloat the size of the early
+ * boot code which uses the firmware version space functions.
+ */
+
+/**
+ * Check the CRC of the kernel version secure storage context.
+ *
+ * Use this if reading from secure storage may be flaky, and you want to retry
+ * reading it several times.
+ *
+ * This may be called before vb2_context_init().
+ *
+ * @param ctx		Context pointer
+ * @return VB2_SUCCESS, or non-zero error code if error.
+ */
+int vb2_secdatak_check_crc(const struct vb2_context *ctx);
+
+/**
+ * Create fresh data in the secure storage context.
+ *
+ * Use this only when initializing the secure storage context on a new machine
+ * the first time it boots.  Do NOT simply use this if vb2_secdatak_check_crc()
+ * (or any other API in this library) fails; that could allow the secure data
+ * to be rolled back to an insecure state.
+ *
+ * This may be called before vb2_context_init().
+ */
+int vb2_secdatak_create(struct vb2_context *ctx);
+
+/**
+ * Initialize the secure storage context and verify its CRC.
+ *
+ * This must be called before vb2_secdatak_get() or vb2_secdatak_set().
+ *
+ * @param ctx		Context pointer
+ * @return VB2_SUCCESS, or non-zero error code if error.
+ */
+int vb2_secdatak_init(struct vb2_context *ctx);
+
+/**
+ * Read a secure storage value.
+ *
+ * @param ctx		Context pointer
+ * @param param		Parameter to read
+ * @param dest		Destination for value
+ * @return VB2_SUCCESS, or non-zero error code if error.
+ */
+int vb2_secdatak_get(struct vb2_context *ctx,
+		     enum vb2_secdatak_param param,
+		     uint32_t *dest);
+
+/**
+ * Write a secure storage value.
+ *
+ * @param ctx		Context pointer
+ * @param param		Parameter to write
+ * @param value		New value
+ * @return VB2_SUCCESS, or non-zero error code if error.
+ */
+int vb2_secdatak_set(struct vb2_context *ctx,
+		     enum vb2_secdatak_param param,
+		     uint32_t value);
+
 #endif  /* VBOOT_REFERENCE_VBOOT_2SECDATA_H_ */
diff --git a/firmware/2lib/include/2struct.h b/firmware/2lib/include/2struct.h
index b64f4ba8..cbf08901 100644
--- a/firmware/2lib/include/2struct.h
+++ b/firmware/2lib/include/2struct.h
@@ -52,6 +52,9 @@ enum vb2_shared_data_status {
 
 	/* Chose a firmware slot */
 	VB2_SD_STATUS_CHOSE_SLOT = (1 << 3),
+
+	/* Secure data kernel version space initialized */
+	VB2_SD_STATUS_SECDATAK_INIT = (1 << 4),
 };
 
 /*
diff --git a/tests/vb2_secdatak_tests.c b/tests/vb2_secdatak_tests.c
new file mode 100644
index 00000000..1aa059ed
--- /dev/null
+++ b/tests/vb2_secdatak_tests.c
@@ -0,0 +1,114 @@
+/* Copyright 2015 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * Tests for kernel secure storage library.
+ */
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "test_common.h"
+#include "vboot_common.h"
+
+#include "2common.h"
+#include "2api.h"
+#include "2crc8.h"
+#include "2misc.h"
+#include "2secdata.h"
+
+static void test_changed(struct vb2_context *ctx, int changed, const char *why)
+{
+	if (changed)
+		TEST_NEQ(ctx->flags & VB2_CONTEXT_SECDATAK_CHANGED, 0, why);
+	else
+		TEST_EQ(ctx->flags & VB2_CONTEXT_SECDATAK_CHANGED, 0, why);
+
+	ctx->flags &= ~VB2_CONTEXT_SECDATAK_CHANGED;
+};
+
+static void secdatak_test(void)
+{
+	uint8_t workbuf[VB2_WORKBUF_RECOMMENDED_SIZE]
+		__attribute__ ((aligned (VB2_WORKBUF_ALIGN)));
+	struct vb2_context c = {
+		.flags = 0,
+		.workbuf = workbuf,
+		.workbuf_size = sizeof(workbuf),
+	};
+	uint32_t v = 1;
+
+	/* Blank data is invalid */
+	memset(c.secdatak, 0xa6, sizeof(c.secdatak));
+	TEST_EQ(vb2_secdatak_check_crc(&c),
+		VB2_ERROR_SECDATAK_CRC, "Check blank CRC");
+	TEST_EQ(vb2_secdatak_init(&c),
+		 VB2_ERROR_SECDATAK_CRC, "Init blank CRC");
+
+	/* Create good data */
+	TEST_SUCC(vb2_secdatak_create(&c), "Create");
+	TEST_SUCC(vb2_secdatak_check_crc(&c), "Check created CRC");
+	TEST_SUCC(vb2_secdatak_init(&c), "Init created CRC");
+	test_changed(&c, 1, "Create changes data");
+
+	/* Now corrupt it */
+	c.secdatak[2]++;
+	TEST_EQ(vb2_secdatak_check_crc(&c),
+		VB2_ERROR_SECDATAK_CRC, "Check invalid CRC");
+	TEST_EQ(vb2_secdatak_init(&c),
+		 VB2_ERROR_SECDATAK_CRC, "Init invalid CRC");
+
+	/* Make sure UID is checked */
+	{
+		struct vb2_secdatak *sec = (struct vb2_secdatak *)c.secdatak;
+
+		vb2_secdatak_create(&c);
+		sec->uid++;
+		sec->crc8 = vb2_crc8(sec, offsetof(struct vb2_secdatak, crc8));
+
+		TEST_EQ(vb2_secdatak_init(&c), VB2_ERROR_SECDATAK_UID,
+			"Init invalid struct UID");
+	}
+
+	/* Read/write versions */
+	vb2_secdatak_create(&c);
+	c.flags = 0;
+	TEST_SUCC(vb2_secdatak_get(&c, VB2_SECDATAK_VERSIONS, &v),
+		  "Get versions");
+	TEST_EQ(v, 0, "Versions created 0");
+	test_changed(&c, 0, "Get doesn't change data");
+	TEST_SUCC(vb2_secdatak_set(&c, VB2_SECDATAK_VERSIONS, 0x123456ff),
+		  "Set versions");
+	test_changed(&c, 1, "Set changes data");
+	TEST_SUCC(vb2_secdatak_set(&c, VB2_SECDATAK_VERSIONS, 0x123456ff),
+		  "Set versions 2");
+	test_changed(&c, 0, "Set again doesn't change data");
+	TEST_SUCC(vb2_secdatak_get(&c, VB2_SECDATAK_VERSIONS, &v),
+		  "Get versions 2");
+	TEST_EQ(v, 0x123456ff, "Versions changed");
+
+	/* Invalid field fails */
+	TEST_EQ(vb2_secdatak_get(&c, -1, &v),
+		VB2_ERROR_SECDATAK_GET_PARAM, "Get invalid");
+	TEST_EQ(vb2_secdatak_set(&c, -1, 456),
+		VB2_ERROR_SECDATAK_SET_PARAM, "Set invalid");
+	test_changed(&c, 0, "Set invalid field doesn't change data");
+
+	/* Read/write uninitialized data fails */
+	vb2_get_sd(&c)->status &= ~VB2_SD_STATUS_SECDATAK_INIT;
+	TEST_EQ(vb2_secdatak_get(&c, VB2_SECDATAK_VERSIONS, &v),
+		VB2_ERROR_SECDATAK_GET_UNINITIALIZED, "Get uninitialized");
+	test_changed(&c, 0, "Get uninitialized doesn't change data");
+	TEST_EQ(vb2_secdatak_set(&c, VB2_SECDATAK_VERSIONS, 0x123456ff),
+		VB2_ERROR_SECDATAK_SET_UNINITIALIZED, "Set uninitialized");
+	test_changed(&c, 0, "Set uninitialized doesn't change data");
+}
+
+int main(int argc, char* argv[])
+{
+	secdatak_test();
+
+	return gTestSuccess ? 0 : 255;
+}