[Cc'ing Nayna] On Thu, 2019-07-04 at 14:25 +0200, Roberto Sassu wrote: > On 7/4/2019 12:42 PM, Jarkko Sakkinen wrote: > > On Mon, 2019-07-01 at 17:22 +0300, Roberto Sassu wrote: > >> Adding to the discussion Jarkko (the maintainer of the trusted key) and > >> the linux-integrity mailing list. > > > > I'm a co-maintainer (added James and Mimi). > > > >>> some people (including me) have problems with the "trusted" kernel module. > >>> As a result to this also the ecryptfs-module won't load. > >>> (https://bugs.archlinux.org/task/62678) > >>> If you use an "inactive" TPM module, the "trusted" module won't load > >>> anymore. > >>> The command modprobe just responds with "Bad address". > >>> The strace-command shows that init_module fails with EFAULT. > >>> I believe the reason for this is that the trusted-module handles > >>> inactive modules the same as active modules. > >>> This results in an error. > >>> > >>> For example: > >>> > > https://github.com/torvalds/linux/commit/0b6cf6b97b7ef1fa3c7fefab0cac897a1c4a3400#diff-c01228e6d386afb29df6aac17d9dd7abR1251 > >>> > >>> My guess is that init_digests(); returns EFAULT in that case. > >>> The " if (!chip)" check above probably needs to check if the chip is > >>> "inactive". > >>> > >>> "inactive" = still visible to the system, but not functional. > >>> It seems to be the default bios-setting for TPM on thinkpad. > >>> (btw.: i have no clue why anybody would need something like that) > >>> > >>> Sadly i have no idea how you would check for an inactive chip,else i > >>> would have send a patch instead. > >>> But I hope the info i wrote is enough to get it fixed by somebody. > >> > >> Thanks for the report. If you see -EFAULT, tpm_get_random() is probably > >> returning 0. > >> > >> Jarkko, we could consider it as non-critical error, and handle it as if > >> the TPM is not found. What do you think? > > > > Not sure I get this. Wasn't the issue fixed in c78719203fc6 or is there > > something missing? > > It seems it is not enough. A TPM is found but does not return data to > tpm_get_random(), I think. While working with Nayna (and George) on the "tpm: fixes uninitialized allocated banks for IBM vtpm driver" patch, I wondered what happens if the chip is enabled, but none of the banks were enabled. Could this be the "inactive" state? Mimi
