The trusted keys code currently loads a blob into the TPM and unseals
on the handle.  However, it never flushes the handle meaning that
volatile contexts build up until the TPM becomes unusable.  Fix this
by flushing the handle after the unseal.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
---
 drivers/char/tpm/tpm.h                    | 1 -
 drivers/char/tpm/tpm2-cmd.c               | 1 +
 include/linux/tpm.h                       | 1 +
 security/keys/trusted-keys/trusted_tpm2.c | 1 +
 4 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index b9e1547be6b5..5620747da0cf 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h

@@ -218,7 +218,6 @@ int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
 int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
 		    struct tpm_digest *digests);
 int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max);
-void tpm2_flush_context(struct tpm_chip *chip, u32 handle);
 ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id,
 			u32 *value, const char *desc);
 

diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index fdb457704aa7..b87592f4a6c7 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c

@@ -362,6 +362,7 @@ void tpm2_flush_context(struct tpm_chip *chip, u32 handle)
 	tpm_transmit_cmd(chip, &buf, 0, "flushing context");
 	tpm_buf_destroy(&buf);
 }
+EXPORT_SYMBOL(tpm2_flush_context);