tpm: Issue a TPM2_Shutdown for TPM2 devices.
authorJosh Zimmerman <joshz@google.com>
Sun, 25 Jun 2017 21:53:24 +0000 (14:53 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sat, 15 Jul 2017 10:16:11 +0000 (12:16 +0200)
commitb635182b4f41d5c5d7c9e059f6ee336f02921cb9
treeee54cc7d4c55b4e5f6eca181efc021f0c14b95b7
parent5a1e1c62f37e83657b570953cab9855f17fcbc7d
tpm: Issue a TPM2_Shutdown for TPM2 devices.

commit d1bd4a792d3961a04e6154118816b00167aad91a upstream.

If a TPM2 loses power without a TPM2_Shutdown command being issued (a
"disorderly reboot"), it may lose some state that has yet to be
persisted to NVRam, and will increment the DA counter. After the DA
counter gets sufficiently large, the TPM will lock the user out.

NOTE: This only changes behavior on TPM2 devices. Since TPM1 uses sysfs,
and sysfs relies on implicit locking on chip->ops, it is not safe to
allow this code to run in TPM1, or to add sysfs support to TPM2, until
that locking is made explicit.

Signed-off-by: Josh Zimmerman <joshz@google.com>
Fixes: 74d6b3ceaa17 ("tpm: fix suspend/resume paths for TPM 2.0")
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/char/tpm/tpm-chip.c
drivers/char/tpm/tpm-sysfs.c