linux-kernel - Re: [PATCH v2 3/3] tpm: vtpm_proxy: Avoid reading host log when using a virtual device

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Date:   Thu, 11 Mar 2021 01:04:52 +0200
From:   Jarkko Sakkinen <jarkko@...nel.org>
To:     Stefan Berger <stefanb@...ux.ibm.com>
Cc:     peterhuewe@....de, jgg@...pe.ca, linux-integrity@...r.kernel.org,
        linux-security-module@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 3/3] tpm: vtpm_proxy: Avoid reading host log when
 using a virtual device

On Wed, Mar 10, 2021 at 05:19:16PM -0500, Stefan Berger wrote:
> Avoid allocating memory and reading the host log when a virtual device
> is used since this log is of no use to that driver. A virtual
> device can be identified through the flag TPM_CHIP_FLAG_VIRTUAL, which
> is only set for the tpm_vtpm_proxy driver.
> 
> Fixes: 6f99612e2500 ("tpm: Proxy driver for supporting multiple emulated TPMs")
> Signed-off-by: Stefan Berger <stefanb@...ux.ibm.com>
> ---
>  drivers/char/tpm/eventlog/common.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/char/tpm/eventlog/common.c b/drivers/char/tpm/eventlog/common.c
> index 7460f230bae4..8512ec76d526 100644
> --- a/drivers/char/tpm/eventlog/common.c
> +++ b/drivers/char/tpm/eventlog/common.c
> @@ -107,6 +107,9 @@ void tpm_bios_log_setup(struct tpm_chip *chip)
>  	int log_version;
>  	int rc = 0;
>  
> +	if (chip->flags & TPM_CHIP_FLAG_VIRTUAL)
> +		return;
> +
>  	rc = tpm_read_log(chip);
>  	if (rc < 0)
>  		return;
> -- 
> 2.29.2
> 
> 


Reviewed-by: Jarkko Sakkinen <jarkko@...nel.org>


/Jarkko