Sessions are different from transient objects in that their handles
may not be virtualized (because they're used for some hmac
calculations). Additionally when a session is context saved, a
vestigial memory remains in the TPM and if it is also flushed, that
will be lost and the session context will refuse to load next time, so
the code is updated to flush only transient objects after a context
save. Add a separate array (chip->session_tbl) to save and restore
sessions by handle. Use the failure of a context save or load to
signal that the session has been flushed from the TPM and we can
remove its memory from chip->session_tbl.
Sessions are also isolated during each instance of a tpm space. This
means that spaces shouldn't be able to see each other's sessions and
is enforced by ensuring that a space user may only refer to sessions
handles that are present in their own chip->session_tbl. Finally when
a space is closed, all the sessions belonging to it should be flushed
so the handles may be re-used by other spaces.
Note that if we get a session save or load error, all sessions are
effectively flushed. Even though we restore the session buffer, all
the old sessions will refuse to load after the flush and they'll be
purged from our session memory. This means that while transient
context handling is still soft in the face of errors, session handling
is hard (any failure of the model means all sessions are lost).
Fixes-from: Colin Ian King <colin.king@canonical.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Added an ability to virtualize TPM commands into an isolated context
that we call a TPM space because the word context is already heavily
used in the TPM specification. Both the handle areas and bodies (where
necessary) are virtualized.
The mechanism works by adding a new parameter struct tpm_space to the
tpm_transmit() function. This new structure contains the list of virtual
handles and a buffer of page size (currently) for backing storage.
When tpm_transmit() is called with a struct tpm_space instance it will
execute the following sequence:
1. Take locks.
2. Load transient objects from the backing storage by using ContextLoad
and map virtual handles to physical handles.
3. Perform the transaction.
4. Save transient objects to backing storage by using ContextSave and
map resulting physical handle to virtual handle if there is such.
This commit does not implement virtualization support for hmac and
policy sessions.
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: James Bottomley <James.Bottomley@HansenPartnership.com>
James Bottomley