linux-kernel - [PATCH 1/3] tpm: Add a missing check for TPM_CHIP_FLAG_HWRNG

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Date:   Wed, 2 Aug 2023 20:50:13 -0500
From:   Mario Limonciello <mario.limonciello@....com>
To:     <jarkko@...nel.org>, <peterhuewe@....de>
CC:     <linux-kernel@...r.kernel.org>, <linux-integrity@...r.kernel.org>,
        <Jason@...c4.com>, <dragonn@...pl>,
        Mario Limonciello <mario.limonciello@....com>
Subject: [PATCH 1/3] tpm: Add a missing check for TPM_CHIP_FLAG_HWRNG_DISABLED

If the TPM is opted out of hwrng the error handling for
tpm_chip_register() needs to know this so it doesn't try to clean
up an uninitialized chip->hwrng.

Signed-off-by: Mario Limonciello <mario.limonciello@....com>
---
 drivers/char/tpm/tpm-chip.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index e904aae9771be..8f61b784810d6 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -629,7 +629,8 @@ int tpm_chip_register(struct tpm_chip *chip)
 	return 0;
 
 out_hwrng:
-	if (IS_ENABLED(CONFIG_HW_RANDOM_TPM) && !tpm_is_firmware_upgrade(chip))
+	if (IS_ENABLED(CONFIG_HW_RANDOM_TPM) && !tpm_is_firmware_upgrade(chip) &&
+	    !(chip->flags & TPM_CHIP_FLAG_HWRNG_DISABLED))
 		hwrng_unregister(&chip->hwrng);
 out_ppi:
 	tpm_bios_log_teardown(chip);
-- 
2.34.1