Re: [PATCH 1/2] tpm: Move tpm_get_random api into the TPM device driver

[Kent Yoder <key@linux.vnet.ibm.com>]

On Thu, Jul 26, 2012 at 03:12:19PM -0700, H. Peter Anvin wrote:
> On 06/07/2012 11:47 AM, Kent Yoder wrote:
> >Move the tpm_get_random api from the trusted keys code into the TPM
> >device driver itself so that other callers can make use of it. Also,
> >change the api slightly so that the number of bytes read is returned in
> >the call, since the TPM command can potentially return fewer bytes than
> >requested.
> >
> >Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>
> 
> >+int tpm_get_random(u32 chip_num, u8 *out, size_t *max)
> 
> /* ... */
> 
> >  	case Opt_new:
> >-		ret = my_get_random(payload->key, payload->key_len);
> >+		ret = tpm_get_random(TPM_ANY_NUM, payload->key,
> >+				     &payload->key_len);
> 
> payload->key_len is unsigned int, not size_t; this causes an
> overwrite of blob_len on 64-bit platforms.

  Good catch.

Thanks,
Kent

> 
> 	-hpa
> 
> 
> -- 
> H. Peter Anvin, Intel Open Source Technology Center
> I work for Intel.  I don't speak on their behalf.
>