Messages in this thread | | | Subject | Re: [PATCH] tpm: Document UEFI event log quirks | From | Jordan Hand <> | Date | Sun, 7 Jul 2019 21:10:48 -0700 |
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On 7/5/19 3:26 AM, Jarkko Sakkinen wrote: > On Wed, 2019-07-03 at 10:08 -0700, Jordan Hand wrote: >>> +This introduces another problem: nothing guarantees that it is not >>> +called before the stub gets to run. Thus, it needs to copy the final >>> +events table preboot size to the custom configuration table so that >>> +kernel offset it later on. >> >> This doesn't really explain what the size will be used for. Matthew's >> patch description for "tpm: Don't duplicate events from the final event >> log in the TCG2 log" outlines this well. You could maybe word it >> differently but I think the information is necessary: >> >> "We can avoid this problem by looking at the size of the Final Event Log >> just before we call ExitBootServices() and exporting this to the main >> kernel. The kernel can then skip over all events that occured before >> ExitBootServices() and only append events that were not also logged to >> the main log." > > Not exactly sure what is missing from my paragraph. The way I see it has > more information as it states what is used at as the vessel for > exportation (the custom configuration table). > > Maybe something like: > > "Thus, it nees to save the final events table size at the time to the > custom configuration table so that the TPM driver can later on skip the > events generated during the preboot time." > Yes, that sounds more clear to me.
Thanks, Jordan
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