vboot: use vboot2 API to set initial secdatak value

Previously, the initial value for secdatak was embedded
in secdata_tpm.c as a uint8_t array.  Switch to using
vb2api_secdatak_create instead, and write the value in
ctx->secdatak.

Remove an unnecessary call to vb2api_secdata_create in
_factory_initialize_tpm.

BUG=b:124141368, chromium:972956
TEST=make clean && make test-abuild
BRANCH=none

TEST=Check that size and value of initial secdatak
     has not changed.  Apply the patch below and
     check for this output:
_factory_initialize_tpm():266: _factory_initialize_tpm: secdatak sizes are identical? 1
_factory_initialize_tpm():269: _factory_initialize_tpm: secdatak values are identical? 1

diff --git a/src/security/vboot/secdata_tpm.c b/src/security/vboot/secdata_tpm.c
index ff62185107..c1818b482f 100644
--- a/src/security/vboot/secdata_tpm.c
+++ b/src/security/vboot/secdata_tpm.c
@@ -148,6 +148,18 @@ static uint32_t write_secdata(uint32_t index,
        return TPM_E_CORRUPTED_STATE;
 }

+/*
+ * This is derived from rollback_index.h of vboot_reference. see struct
+ * RollbackSpaceKernel for details.
+ */
+static const uint8_t secdata_kernel[] = {
+       0x02,
+       0x4C, 0x57, 0x52, 0x47,
+       0x00, 0x00, 0x00, 0x00,
+       0x00, 0x00, 0x00,
+       0xE8,
+};
+
 /*
  * This is used to initialize the TPM space for recovery hash after defining
  * it. Since there is no data available to calculate hash at the point where TPM
@@ -250,6 +262,11 @@ static uint32_t _factory_initialize_tpm(struct vb2_context *ctx)
         * indication that TPM factory initialization was successfully
         * completed.
         */
+       VBDEBUG("%s: secdatak sizes are identical? %d\n", __func__,
+               sizeof(secdata_kernel) == sizeof(ctx->secdatak));
+       VBDEBUG("%s: secdatak values are identical? %d\n", __func__,
+               memcmp(secdata_kernel, ctx->secdatak,
+                      sizeof(secdata_kernel)) == 0);
        RETURN_ON_FAILURE(set_kernel_space(ctx->secdatak));

        if (CONFIG(VBOOT_HAS_REC_HASH_SPACE))
@@ -452,7 +469,7 @@ uint32_t antirollback_read_space_firmware(struct vb2_context *ctx)

        /* Read the firmware space. */
        rv = read_space_firmware(ctx);
-       if (rv == TPM_E_BADINDEX) {
+       if (true) {
                /*
                 * This seems the first time we've run. Initialize the TPM.
                 */

Change-Id: I74261453df6cc55ef3f38d8fb922bcc604084c0a
Signed-off-by: Joel Kitching <kitching@google.com>
Cq-Depend: chromium:1652874, chromium:1655049
Reviewed-on: https://review.coreboot.org/c/coreboot/+/33386
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

src/security/vboot/secdata_tpm.c

@@ -124,18 +124,6 @@ static uint32_t write_secdata(uint32_t index,
 	return TPM_E_CORRUPTED_STATE;
 }
 
-/*
- * This is derived from rollback_index.h of vboot_reference. see struct
- * RollbackSpaceKernel for details.
- */
-static const uint8_t secdata_kernel[] = {
-	0x02,
-	0x4C, 0x57, 0x52, 0x47,
-	0x00, 0x00, 0x00, 0x00,
-	0x00, 0x00, 0x00,
-	0xE8,
-};
-
 /*
  * This is used to initialize the TPM space for recovery hash after defining
  * it. Since there is no data available to calculate hash at the point where TPM
@@ -217,7 +205,7 @@ static uint32_t set_firmware_space(const void *firmware_blob)
 static uint32_t set_kernel_space(const void *kernel_blob)
 {
 	return set_space("kernel", KERNEL_NV_INDEX, kernel_blob,
-			 sizeof(secdata_kernel), rw_space_attributes, NULL, 0);
+			 VB2_SECDATAK_SIZE, rw_space_attributes, NULL, 0);
 }
 
 static uint32_t set_rec_hash_space(const uint8_t *data)
@@ -238,7 +226,7 @@ static uint32_t _factory_initialize_tpm(struct vb2_context *ctx)
 	 * indication that TPM factory initialization was successfully
 	 * completed.
 	 */
-	RETURN_ON_FAILURE(set_kernel_space(secdata_kernel));
+	RETURN_ON_FAILURE(set_kernel_space(ctx->secdatak));
 
 	if (CONFIG(VBOOT_HAS_REC_HASH_SPACE))
 		RETURN_ON_FAILURE(set_rec_hash_space(rec_hash_data));
@@ -342,16 +330,15 @@ static uint32_t _factory_initialize_tpm(struct vb2_context *ctx)
 	VBDEBUG("TPM: Clearing owner\n");
 	RETURN_ON_FAILURE(tpm_clear_and_reenable());
 
-	/* Define and initialize the kernel space */
+	/* Define and write secdatak kernel space. */
 	RETURN_ON_FAILURE(safe_define_space(KERNEL_NV_INDEX,
 					    TPM_NV_PER_PPWRITE,
-					    sizeof(secdata_kernel)));
+					    VB2_SECDATAK_SIZE));
 	RETURN_ON_FAILURE(write_secdata(KERNEL_NV_INDEX,
-					secdata_kernel,
+					ctx->secdatak,
-					sizeof(secdata_kernel)));
+					VB2_SECDATAK_SIZE));
 
-	/* Defines and sets vb2 secdata space */
+	/* Define and write secdata firmware space. */
-	vb2api_secdata_create(ctx);
 	RETURN_ON_FAILURE(safe_define_space(FIRMWARE_NV_INDEX,
 	                                    TPM_NV_PER_GLOBALLOCK |
 	                                    TPM_NV_PER_PPWRITE,
@@ -393,8 +380,9 @@ static uint32_t factory_initialize_tpm(struct vb2_context *ctx)
 {
 	uint32_t result;
 
-	/* Defines and sets vb2 secdata space */
+	/* Set initial values of secdata and secdatak spaces. */
 	vb2api_secdata_create(ctx);
+	vb2api_secdatak_create(ctx);
 
 	VBDEBUG("TPM: factory initialization\n");