On 24 October 2017 at 21:41, Jason Gunthorpe <jgunthorpe@xxxxxxxxxxxxxxxxxxxx> wrote: > On Tue, Oct 24, 2017 at 09:37:33PM +0530, PrasannaKumar Muralidharan wrote: >> Hi Jason, >> >> On 24 October 2017 at 21:25, Jason Gunthorpe >> <jgunthorpe@xxxxxxxxxxxxxxxxxxxx> wrote: >> > On Tue, Oct 24, 2017 at 09:21:15PM +0530, PrasannaKumar Muralidharan wrote: >> > >> >> 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. > >> 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
