On Thu, Oct 03, 2019 at 08:39:10AM -0400, Mimi Zohar wrote: > On Thu, 2019-10-03 at 14:32 +0300, Jarkko Sakkinen wrote: > > On Wed, Oct 02, 2019 at 08:40:24AM -0400, Mimi Zohar wrote: > > > On Thu, 2019-09-26 at 16:12 +0300, Jarkko Sakkinen wrote: > > > > On Thu, Sep 26, 2019 at 03:46:35PM +0300, Jarkko Sakkinen wrote: > > > > > On Wed, Sep 25, 2019 at 04:48:41PM +0300, Jarkko Sakkinen wrote: > > > > > > - tpm_buf_reset(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_RANDOM); > > > > > > + tpm_buf_reset(&buf, data_ptr, PAGE_SIZE, > > > > > > + TPM2_ST_NO_SESSIONS, TPM2_CC_PCR_EXTEND); > > > > > > > > > > Oops. > > > > > > > > Maybe we could use random as the probe for TPM version since we anyway > > > > send a TPM command as a probe for TPM version: > > > > > > > > 1. Try TPM2 get random. > > > > 2. If fail, try TPM1 get random. > > > > 3. Output random number to klog. > > > > > > > > Something like 8 bytes would be sufficient. This would make sure that > > > > no new change breaks tpm_get_random() and also this would give some > > > > feedback that TPM is at least somewhat working. > > > > > > That involves sending 2 TPM commands. At what point does this occur? > > > On registration? Whenever getting a random number? Is the result > > > cached in chip->flags? > > > > On registeration. It is just printed to klog. > > What sets "TPM_CHIP_FLAG_TPM2" in chip->flags? And when? > > > > > > Will this delay the TPM initialization, causing IMA to go into "TPM > > > bypass mode"? > > > > Of course it will delay the init. > > Delaying the init will most likely cause regressions on systems with > TPM 1.2 systems. > > Instead of sending the TPM 2.0 command and on failure sending the TPM > 1.2 version of the command, could chip->flags be tested? And if not > chip->flags, then provide the TPM version as part of registration. No rush pushing this forward. I got your point. > > As I've stated before the real fix for the bypass issue would be > > to make TPM as part of the core but this has not received much > > appeal. I think I've sent patch for this once. > > I must have missed this discussion. Yeah, I think that'd be a great idea. We need a better control on TPM core as multiple subsystem's depend on it in API level. Something to reconsider in future. /Jarkko
