On Wed, Sep 05, 2018 at 01:41:59PM +0200, Roberto Sassu wrote: > The TPM driver currently relies on the crypto subsystem to determine the > digest size of supported TPM algorithms. In the future, TPM vendors might > implement new algorithms in their chips, and those algorithms might not > be supported by the crypto subsystem. > > Usually, vendors provide patches for the new hardware, and likely > the crypto subsystem will be updated before the new algorithm is > introduced. However, old kernels might be updated later, after patches > are included in the mainline kernel. This would leave the opportunity > for attackers to misuse PCRs, as PCR banks with an unknown algorithm > are not extended. > > This patch set provides a long term solution for this issue. If a TPM > algorithm is not known by the crypto subsystem, the TPM driver retrieves > the digest size from the TPM with a PCR read. All the PCR banks are > extended, even if the algorithm is not yet supported by the crypto > subsystem. I'm sorry. I missed this before checking through the mails. In future, please add me either to to-field so that they arrive to my inbox and do not get filtered to linux-integrity folder, which I go through with time at most once a week. /Jarkko
