Re: [tpmdd-devel] [PATCH] tpm: remove chip_num parameter from in-kernel API
PrasannaKumar Muralidharan <[email protected]>
| Newsgroups | net.sourceforge.lists.tpmdd-devel,org.kernel.vger.keyrings,org.kernel.vger.linux-crypto,org.kernel.vger.linux-integrity,org.kernel.vger.linux-kernel,org.kernel.vger.linux-security-module |
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| Message-ID | <CANc+2y4VYWUON2Uo5M7SyyxtrMPiyY1Ln0WEkFLzKsHJ0v_keA@mail.gmail.com> |
On 24 October 2017 at 21:41, Jason Gunthorpe <[email protected]> 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 >> <[email protected]> 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