vboot2: Support reboot requested by secdata

When a TPM goes from the disabled state to the enabled state, it must
reboot after being enabled, before it can be initialized.  In vboot1,
TLCL was part of vboot and this was handled internally.  In vboot2, the
caller must set a context flag, so that vboot can decide whether to
allow the reboot, or whether to go directly to recovery mode.  This
check is necessary to handle the following cases:

1) The device is booting normally, but the TPM needs a reboot.  This
should simply reboot, without going to recovery mode.

2) The device is booting in recovery mode, but the TPM needs a reboot.
If this is the first time it asked us, allow the reboot.

3) The TPM asked for a reboot last time, so we did.  And it's still
asking.  Don't reboot, because that runs the risk that whatever is wrong
won't be fixed next boot either, and we'll get stuck in a reboot loop
that will prevent recovery.  Boot into recovery mode.

Add a new NvStorage bit to track whether the TPM requested a reboot on
the previous boot.  That's better than what we did in vboot1, where we
used a special recovery request.  Vboot1 couldn't track getting stuck in
a reboot loop in normal mode, only in recovery mode.  The new code can
catch both.

BUG=chrome-os-partner:45462
BRANCH=ryu
TEST=make runtests

Change-Id: I2ee54af107275ccf64a6cb41132b7a0fc02bb983
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/300572
Tested-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
This commit is contained in:
Randall Spangler
2015-09-17 12:54:51 -07:00
committed by chrome-bot
parent 85f646613c
commit c8e48545d5
13 changed files with 148 additions and 4 deletions

View File

@@ -44,6 +44,27 @@ int vb2api_fw_phase1(struct vb2_context *ctx)
/* Initialize NV context */
vb2_nv_init(ctx);
/*
* Handle caller-requested reboot due to secdata. Do this before we
* even look at secdata. If we fail because of a reboot loop we'll be
* the first failure so will get to set the recovery reason.
*/
if (!(ctx->flags & VB2_CONTEXT_SECDATA_WANTS_REBOOT)) {
/* No reboot requested */
vb2_nv_set(ctx, VB2_NV_TPM_REQUESTED_REBOOT, 0);
} else if (vb2_nv_get(ctx, VB2_NV_TPM_REQUESTED_REBOOT)) {
/*
* Reboot requested... again. Fool me once, shame on you.
* Fool me twice, shame on me. Fail into recovery to avoid
* a reboot loop.
*/
vb2_fail(ctx, VB2_RECOVERY_RO_TPM_REBOOT, 0);
} else {
/* Reboot requested for the first time */
vb2_nv_set(ctx, VB2_NV_TPM_REQUESTED_REBOOT, 1);
return VB2_ERROR_API_PHASE1_SECDATA_REBOOT;
}
/* Initialize secure data */
rv = vb2_secdata_init(ctx);
if (rv)