On Wed, 2021-01-13 at 22:48 +0200, Jarkko Sakkinen wrote:
On Tue, Jan 12, 2021 at 05:59:57PM -0800, James Bottomley wrote:
quoted
This represents v5 which has the spelling mistake fixed and the
WARN
on unrecognized TPM hash algorithm becoming a dev_err.
We've had a fairly extensive discussion and iterated to agreement
on
the output format, which becomes our ABI being one single compact
hex
representation of the hash value per file according to sysfs rules,
with the file hierarchy going under
/sys/class/tpm/tmp<x>/pcr-<hash>/<pcr number>
So to get the value of PCR 7 in the sha256 bank of the default TPM
I'd do
cat /sys/class/tpm/tpm0/pcr-sha256/7
2ED93F199692DC6788EFA6A1FE74514AB9760B2A6CEEAEF6C808C13E4ABB0D42
If you need the binary hash of a set of PCRs, as is required for
TPM
policy statements that lock to PCRs, you'd use something like:
cat /sys/class/tpm/tpm0/pcr-sha256/{1,6,7}|xxd -r -p|sha256sum
Which produces the binary hash of PCRs 1, 6 and 7 in that order.
Note that this patch also adds the sha1 bank for TPM 1.2 in the
same
manner (one file per PCR) but does not remove the existing pcrs
file
which has the space separated all PCRs in one file format of
PCR-00: 7D 29 CB 08 0C 0F C4 16 7A 0E 9A F7 C6 D3 97 CD C1 21 A7
69
PCR-01: 9C B6 79 4C E4 4B 62 97 4C AB 55 13 1A 2F 7E AE 09 B3 30
BE
...
James
---
James Bottomley (1):
tpm: add sysfs exports for all banks of PCR registers
drivers/char/tpm/tpm-sysfs.c | 179
+++++++++++++++++++++++++++++++++++
include/linux/tpm.h | 9 +-
2 files changed, 187 insertions(+), 1 deletion(-)
--
2.26.2
After clearing out Greg's remarks, can you use jarkko@kernel.org
for the next version?
Sorry, it's a force of habit process: i go back to version n-1 and copy
the to and cc list ... so the promise to sent to kernel.org didn't get
realised.
I'll just do a resend since there are no changes requested.
James