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
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
Signed-off-by: Joel Kitching <firstname.lastname@example.org>
Cq-Depend: chromium:1819380, chromium:1939168
Tested-by: Joel Kitching <email@example.com>
Reviewed-by: Andrey Pronin <firstname.lastname@example.org>
Reviewed-by: Julius Werner <email@example.com>
Commit-Queue: Joel Kitching <firstname.lastname@example.org>
28 files changed