vboot/secdata_mock: Make v0 kernel secdata context

The new kernel secdata v1 stores the last read EC hash, and reboots the
device during EC software sync when that hash didn't match the currently
active hash on the EC (this is used with TPM_CR50 to support EC-EFS2 and
pretty much a no-op for other devices). Generally, of course the whole
point of secdata is always that it persists across reboots, but with
MOCK_SECDATA we can't do that. Previously we always happened to somewhat
get away with presenting freshly-reinitialized data for MOCK_SECDATA on
every boot, but with the EC hash feature in secdata v1, that would cause
a reboot loop. The simplest solution is to just pretend we're a secdata
v0 device when using MOCK_SECDATA.

This was encountered on using a firmware built with MOCK_SECDATA but had
EC software sync enabled.

BUG=b:187843114
BRANCH=None
TEST=`USE=mocktpm cros build-ap -b keeby`; Flash keeby device, verify
that DUT does not continuously reboot with EC software sync enabled.

Signed-off-by: Aseda Aboagye <aaboagye@google.com>
Change-Id: Id8e81afcddadf27d9eec274f7f85ff1520315aaa
Reviewed-on: https://review.coreboot.org/c/coreboot/+/54304
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

1 files changed, 13 insertions, 1 deletions

diff --git a/src/security/vboot/secdata_mock.c b/src/security/vboot/secdata_mock.c
index 78cb3e6063..5792b41633 100644
--- a/src/security/vboot/secdata_mock.c
+++ b/src/security/vboot/secdata_mock.c
@@ -28,7 +28,19 @@ vb2_error_t antirollback_write_space_firmware(struct vb2_context *ctx)
 
 vb2_error_t antirollback_read_space_kernel(struct vb2_context *ctx)
 {
-	vb2api_secdata_kernel_create(ctx);
+	/*
+	 * The new kernel secdata v1 stores the last read EC hash, and reboots the
+	 * device during EC software sync when that hash didn't match the currently
+	 * active hash on the EC (this is used with TPM_CR50 to support EC-EFS2 and
+	 * pretty much a no-op for other devices). Generally, of course the whole
+	 * point of secdata is always that it persists across reboots, but with
+	 * MOCK_SECDATA we can't do that. Previously we always happened to somewhat
+	 * get away with presenting freshly-reinitialized data for MOCK_SECDATA on
+	 * every boot, but with the EC hash feature in secdata v1, that would cause
+	 * a reboot loop. The simplest solution is to just pretend we're a secdata
+	 * v0 device when using MOCK_SECDATA.
+	 */
+	vb2api_secdata_kernel_create_v0(ctx);
 	return VB2_SUCCESS;
 }