[PATCH V2] tpm: Don't make log failures fatal

* [PATCH V2] tpm: Don't make log failures fatal
@ 2020-01-02 21:55 Matthew Garrett
  2020-01-03 19:09 ` Jerry Snitselaar
                   ` (2 more replies)
  0 siblings, 3 replies; 7+ messages in thread
From: Matthew Garrett @ 2020-01-02 21:55 UTC (permalink / raw)
  To: linux-integrity; +Cc: Jarkko Sakkinen, Matthew Garrett, Matthew Garrett, stable

If a TPM is in disabled state, it's reasonable for it to have an empty
log. Bailing out of probe in this case means that the PPI interface
isn't available, so there's no way to then enable the TPM from the OS.
In general it seems reasonable to ignore log errors - they shouldn't
interfere with any other TPM functionality.

Signed-off-by: Matthew Garrett <mjg59@google.com>
Cc: stable@vger.kernel.org
---

V2: make tpm_bios_log_setup() void, since we're not using the return
code now. Fix typo in patch description.

 drivers/char/tpm/eventlog/common.c | 12 ++++--------
 drivers/char/tpm/tpm-chip.c        |  4 +---
 drivers/char/tpm/tpm.h             |  2 +-
 3 files changed, 6 insertions(+), 12 deletions(-)

diff --git a/drivers/char/tpm/eventlog/common.c b/drivers/char/tpm/eventlog/common.c
index 7a0fca659b6a6..7460f230bae4c 100644
--- a/drivers/char/tpm/eventlog/common.c
+++ b/drivers/char/tpm/eventlog/common.c
@@ -99,11 +99,8 @@ static int tpm_read_log(struct tpm_chip *chip)
  *
  * If an event log is found then the securityfs files are setup to
  * export it to userspace, otherwise nothing is done.
- *
- * Returns -ENODEV if the firmware has no event log or securityfs is not
- * supported.
  */
-int tpm_bios_log_setup(struct tpm_chip *chip)
+void tpm_bios_log_setup(struct tpm_chip *chip)
 {
 	const char *name = dev_name(&chip->dev);
 	unsigned int cnt;
@@ -112,7 +109,7 @@ int tpm_bios_log_setup(struct tpm_chip *chip)
 
 	rc = tpm_read_log(chip);
 	if (rc < 0)
-		return rc;
+		return;
 	log_version = rc;
 
 	cnt = 0;
@@ -158,13 +155,12 @@ int tpm_bios_log_setup(struct tpm_chip *chip)
 		cnt++;
 	}
 
-	return 0;
+	return;
 
 err:
-	rc = PTR_ERR(chip->bios_dir[cnt]);
 	chip->bios_dir[cnt] = NULL;
 	tpm_bios_log_teardown(chip);
-	return rc;
+	return;
 }
 
 void tpm_bios_log_teardown(struct tpm_chip *chip)
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 3d6d394a86618..58073836b5555 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -596,9 +596,7 @@ int tpm_chip_register(struct tpm_chip *chip)
 
 	tpm_sysfs_add_device(chip);
 
-	rc = tpm_bios_log_setup(chip);
-	if (rc != 0 && rc != -ENODEV)
-		return rc;
+	tpm_bios_log_setup(chip);
 
 	tpm_add_ppi(chip);
 
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index b9e1547be6b51..1df2cf40ab794 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -236,7 +236,7 @@ int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u8 *cmd,
 int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space, void *buf,
 		      size_t *bufsiz);
 
-int tpm_bios_log_setup(struct tpm_chip *chip);
+void tpm_bios_log_setup(struct tpm_chip *chip);
 void tpm_bios_log_teardown(struct tpm_chip *chip);
 int tpm_dev_common_init(void);
 void tpm_dev_common_exit(void);
-- 
2.24.1.735.g03f4e72817-goog


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