app-crypt/trousers: Skip tscd.service for TPM2 devices

[sayanchowdhury]

trousers supports TPM 1.2, and fails for TPM 2. This commits
skips the tcsd service if TPM 2 is detected.

Fixes flatcar/Flatcar#208

Signed-off-by: Sayan Chowdhury schowdhury@microsoft.com

Testing done

CI Running http://jenkins.infra.kinvolk.io:8080/job/os/job/manifest/3911/cldsv/

[pothos]

Suggested change

	ConditionSecurity=!tpm2

This could be used in [Unit] instead of ExecCondition under [Service], as suggested in flatcar/Flatcar#208 (comment)

[pothos]

Yet, only for Alpha, and for Stable/Beta we should pick the change as it is here. Maybe the above suggestion is better for a follow-up PR only for Alpha.

[sayanchowdhury]

CI Passed

• TPM 2

core@localhost ~ $ sudo systemctl status tcsd
○ tcsd.service - TCG Core Services Daemon
     Loaded: loaded (8;;file://localhost/usr/lib/systemd/system/tcsd.service^G/usr/lib/systemd/system/tcsd.service8;;^G; disabled; vendor preset: disabled)
     Active: inactive (dead) (Result: exec-condition) since Fri 2021-10-22 10:43:50 UTC; 1min 28s ago
  Condition: start condition failed at Fri 2021-10-22 10:43:49 UTC; 1min 29s ago
    Process: 915 ExecCondition=/bin/bash -c /usr/bin/test $(cat /sys/class/tpm/*/tpm_version_major | grep -m 1 1 || echo 0) -eq 1 (code=exited, status=1/FAILURE)
        CPU: 20ms

Oct 22 10:43:49 localhost systemd[1]: Starting TCG Core Services Daemon...
Oct 22 10:43:50 localhost systemd[1]: tcsd.service: Skipped due to 'exec-condition'.
Oct 22 10:43:50 localhost systemd[1]: Condition check resulted in TCG Core Services Daemon being skipped.

• For TPM 1.2

● tcsd.service - TCG Core Services Daemon
     Loaded: loaded (8;;file://localhost/usr/lib/systemd/system/tcsd.service^G/usr/lib/systemd/system/tcsd.service8;;^G; disabled; vendor preset: disabled)
     Active: active (running) since Fri 2021-10-22 10:46:53 UTC; 13s ago
    Process: 802 ExecCondition=/bin/bash -c /usr/bin/test $(cat /sys/class/tpm/*/tpm_version_major | grep -m 1 1 || echo 0) -eq 1 (code=exited, status=0/SUCCESS)
   Main PID: 814 (tcsd)
      Tasks: 1 (limit: 7456)
     Memory: 824.0K
        CPU: 23ms
     CGroup: /system.slice/tcsd.service
             └─814 /usr/sbin/tcsd -f

Oct 22 10:46:53 localhost systemd[1]: Starting TCG Core Services Daemon...
Oct 22 10:46:53 localhost systemd[1]: Started TCG Core Services Daemon.