[PATCH v3 2/2] tpm: Disable TPM on TPM_RC_INITIALIZE

[Breno Leitao <leitao@debian.org>]

From: Jarkko Sakkinen <jarkko@kernel.org>

If the TPM has been spuriously disabled, the game is over. Let's reflect
this truth with TPM_CHIP_FLAG_DISABLE.

Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
[leitao@debian.org: check rc before the loop breaks out on anything but
 RETRY/TESTING, skip TPM2_Startup, which a TPM that is already started
 fails with TPM2_RC_INITIALIZE, and fix the TPM2_RC_INITIALIZE and
 chip->flags typos]
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
---
 drivers/char/tpm/tpm-interface.c | 5 +++++
 drivers/char/tpm/tpm2-cmd.c      | 2 ++
 2 files changed, 7 insertions(+)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 977e205807033d..dd6bb518ab7d9c 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -252,6 +252,11 @@ ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz)
 		if (ret < 0)
 			break;
 		rc = be32_to_cpu(header->return_code);
+		/* A TPM that is already started fails TPM2_Startup this way. */
+		if (rc == TPM2_RC_INITIALIZE && cc != TPM2_CC_STARTUP) {
+			chip->flags |= TPM_CHIP_FLAG_DISABLE;
+			break;
+		}
 		if (rc != TPM2_RC_RETRY && rc != TPM2_RC_TESTING)
 			break;
 		/*
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 4b2bb2ddc321a9..65928ae85b496c 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -724,6 +724,8 @@ int tpm2_auto_startup(struct tpm_chip *chip)
 		goto out;
 
 	if (rc == TPM2_RC_INITIALIZE) {
+		chip->flags &= ~TPM_CHIP_FLAG_DISABLE;
+
 		rc = tpm2_startup(chip);
 		if (rc)
 			goto out;

-- 
2.53.1-Meta