linux-kernel - Re: [PATCH] tpm: do handle area size validation only when TPM space used

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Date:   Tue, 28 Mar 2017 13:24:53 +0300
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Alexander.Steffen@...ineon.com
Cc:     tpmdd-devel@...ts.sourceforge.net,
        linux-security-module@...r.kernel.org,
        Peter Huewe <peterhuewe@....de>,
        Marcel Selhorst <tpmdd@...horst.net>,
        Jason Gunthorpe <jgunthorpe@...idianresearch.com>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] tpm: do handle area size validation only when TPM space
 used

So do you need this or not?

/Jarkko

On Mon, Mar 27, 2017 at 12:08:15AM +0300, Jarkko Sakkinen wrote:
> In order to not cause backwards compatibility issues with
> /dev/tpm0 disable handle area size validation if tpm_transmit
> is not called with a TPM space.
> 
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@....fi>
> ---
>  drivers/char/tpm/tpm-interface.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index bf0c3fa..158c1db 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -328,7 +328,9 @@ unsigned long tpm_calc_ordinal_duration(struct tpm_chip *chip,
>  }
>  EXPORT_SYMBOL_GPL(tpm_calc_ordinal_duration);
>  
> -static bool tpm_validate_command(struct tpm_chip *chip, const u8 *cmd,
> +static bool tpm_validate_command(struct tpm_chip *chip,
> +				 struct tpm_space *space,
> +				 const u8 *cmd,
>  				 size_t len)
>  {
>  	const struct tpm_input_header *header = (const void *)cmd;
> @@ -340,6 +342,9 @@ static bool tpm_validate_command(struct tpm_chip *chip, const u8 *cmd,
>  	if (len < TPM_HEADER_SIZE)
>  		return false;
>  
> +	if (!space)
> +		return true;
> +
>  	if (chip->flags & TPM_CHIP_FLAG_TPM2 && chip->nr_commands) {
>  		cc = be32_to_cpu(header->ordinal);
>  
> @@ -386,7 +391,7 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
>  	unsigned long stop;
>  	bool need_locality;
>  
> -	if (!tpm_validate_command(chip, buf, bufsiz))
> +	if (!tpm_validate_command(chip, space, buf, bufsiz))
>  		return -EINVAL;
>  
>  	if (bufsiz > TPM_BUFSIZE)
> -- 
> 2.9.3
>