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

From: Kent Yoder
Date: Fri Jul 27 2012 - 10:50:59 EST


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@xxxxxxxxxxxxxxxxxx>
>
> >+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.
>

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