vboot/secdata: rewrite rollback_index and centralize reads/writes

In current kernel verification code, secdata reads and writes
are spread throughout the code.  vboot2's design is to use
vb2_context.secdata_* for storing the state of secdata spaces,
and have the caller (depthcharge) read/save this field when
necessary.

Centralize secdata reads/writes into the functions of
secdata_tpm.c, previously known as rollback_index.c.
Functions which directly read/write to the TPM space are modified
to use vb2_secdata_*_get and vb2_secdata_*_set.

The secure spaces get read/flushed by functions in
vboot_api_kernel.c.  These calls and the underlying functions
from secdata_tpm.c will eventually be relocated to depthcharge.

Create a new external function vb2ex_commit_data, which commits
any modified nvdata/secdata.  Currently the depthcharge
implementation of this function only writes nvdata, but once
secdata TPM drivers have been migrated from vboot_reference to
depthcharge, it will also commit these data spaces.

This CL also removes the VbExNvStorageRead call from
vb2_kernel_setup, and the data is instead read in depthcharge
CL:1819379, right before calling VbSelectAndLoadKernel.

As such, both the VbExNvStorageRead and VbExNvStorageWrite
functions may be removed.

Finally, create a vb2_secdata_kernel_lock function, which should
be used right before attempting to leave vboot (by booting an OS
or chainloading to another firmware).  This should eventually be
exposed as a vb2ex_ API function and relocated to depthcharge.

BUG=b:124141368, chromium:972956, chromium:1006689
TEST=make clean && make runtests
BRANCH=none

Change-Id: Ifbfb21122af0bf85e22a6d3a0d48a1db7f7c25b7
Signed-off-by: Joel Kitching <kitching@google.com>
Cq-Depend: chromium:1819380, chromium:1939168
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/1728298
Tested-by: Joel Kitching <kitching@chromium.org>
Reviewed-by: Andrey Pronin <apronin@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Commit-Queue: Joel Kitching <kitching@chromium.org>

1 files changed, 21 insertions, 0 deletions

diff --git a/firmware/2lib/include/2return_codes.h b/firmware/2lib/include/2return_codes.h
index e6109485..0ab9e750 100644
--- a/firmware/2lib/include/2return_codes.h
+++ b/firmware/2lib/include/2return_codes.h
@@ -240,6 +240,27 @@ enum vb2_return_code {
 	/* Bad struct version in vb2_secdata_fwmp_check() */
 	VB2_ERROR_SECDATA_FWMP_VERSION,
 
+	/* Error reading secdata_firmware from storage backend */
+	VB2_ERROR_SECDATA_FIRMWARE_READ,
+
+	/* Error writing secdata_firmware to storage backend */
+	VB2_ERROR_SECDATA_FIRMWARE_WRITE,
+
+	/* Error locking secdata_firmware in storage backend */
+	VB2_ERROR_SECDATA_FIRMWARE_LOCK,
+
+	/* Error reading secdata_kernel from storage backend */
+	VB2_ERROR_SECDATA_KERNEL_READ,
+
+	/* Error writing secdata_kernel to storage backend */
+	VB2_ERROR_SECDATA_KERNEL_WRITE,
+
+	/* Error locking secdata_kernel in storage backend */
+	VB2_ERROR_SECDATA_KERNEL_LOCK,
+
+	/* Error reading secdata_fwmp from storage backend */
+	VB2_ERROR_SECDATA_FWMP_READ,
+
 	/**********************************************************************
 	 * Common code errors
 	 */