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

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Date:   Thu, 03 Aug 2023 11:59:41 +0300
From:   "Jarkko Sakkinen" <jarkko@...nel.org>
To:     "Mario Limonciello" <mario.limonciello@....com>,
        <peterhuewe@....de>
Cc:     <linux-kernel@...r.kernel.org>, <linux-integrity@...r.kernel.org>,
        <Jason@...c4.com>, <dragonn@...pl>
Subject: Re: [PATCH 1/3] tpm: Add a missing check for
 TPM_CHIP_FLAG_HWRNG_DISABLED

On Thu Aug 3, 2023 at 4:50 AM EEST, Mario Limonciello wrote:
> 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

Please add a fixes tag.

BR, Jarkko