Re: [PATCH] tpm_crb: check for bad response size

From	Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH] tpm_crb: check for bad response size
Date	2017-03-11 09:50 +0100
Message-ID	<tjKSR-dL-7@gated-at.bofh.it> (permalink)
References	<tjDol-3gr-9@gated-at.bofh.it>
Organization	Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo

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On Fri, Mar 10, 2017 at 05:46:04PM -0700, Jerry Snitselaar wrote:
> Make sure size of response buffer is at least 6 bytes, or
> we will underflow and pass large size_t to memcpy_fromio().
> This was encountered while testing earlier version of
> locality patchset.
> 
> Fixes: 30fc8d138e912 ("tpm: TPM 2.0 CRB Interface")
> Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>

Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

/Jarkko

> ---
>  drivers/char/tpm/tpm_crb.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
> index 89dc8a176ff1..cda4f312d1c9 100644
> --- a/drivers/char/tpm/tpm_crb.c
> +++ b/drivers/char/tpm/tpm_crb.c
> @@ -236,7 +236,7 @@ static int crb_recv(struct tpm_chip *chip, u8 *buf, size_t count)
>  
>  	memcpy_fromio(buf, priv->rsp, 6);
>  	expected = be32_to_cpup((__be32 *) &buf[2]);
> -	if (expected > count)
> +	if (expected > count || expected < 6)
>  		return -EIO;
>  
>  	memcpy_fromio(&buf[6], &priv->rsp[6], expected - 6);
> -- 
> 2.11.0.258.ge05806da9
>

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[PATCH] tpm_crb: check for bad response size Jerry Snitselaar <jsnitsel@redhat.com> - 2017-03-11 01:50 +0100
  Re: [PATCH] tpm_crb: check for bad response size Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> - 2017-03-11 09:50 +0100

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