On 24 October 2017 at 21:41, Jason Gunthorpe
[off-list ref] wrote:

On Tue, Oct 24, 2017 at 09:37:33PM +0530, PrasannaKumar Muralidharan wrote:

quoted

Hi Jason,

On 24 October 2017 at 21:25, Jason Gunthorpe
[off-list ref] wrote:

quoted

On Tue, Oct 24, 2017 at 09:21:15PM +0530, PrasannaKumar Muralidharan wrote:

quoted

Please check the RFC [1]. It does use chip id. The rfc has issues and
has to be fixed but still there could be users of the API.

1. https://www.spinics.net/lists/linux-crypto/msg28282.html

That patch isn't safe at all. You need to store a kref to th chip in
the hwrng, not parse a string.

The drivers/char/hw_random/tpm-rng.c module does not store the chip
reference so I guess the usage is safe.

It is using the default TPM, it is always safe to use the default tpm.

quoted

The RFC is just a sample use case of the API.

Well, a wrong example not to be emulated, and I think, further shows
how Jarkko's direction is the right one.

I am wondering why it is wrong. Isn't the chip id valid till it is
unregistered? If so the rfc is correct. Please explain, may be I am
missing something.

Thanks,
PrasannaKumar