phpMan > man > systemd-boot-system-token.service(8)

SYSTEMD-BOOT-SYSTEM-TOKEN.SERVICE(systemd-boot-system-token.servSYSTEMD-BOOT-SYSTEM-TOKEN.SERVICE(8)



NAME
       systemd-boot-system-token.service - Generate an initial boot loader system token and random
       seed

SYNOPSIS
       systemd-boot-system-token.service

DESCRIPTION
       systemd-boot-system-token.service is a system service that automatically generates a 'system
       token' to store in an EFI variable in the system's NVRAM and a random seed to store on the
       EFI System Partition ESP on disk. The boot loader may then combine these two randomized data
       fields by cryptographic hashing, and pass it to the OS it boots as initialization seed for
       its entropy pool. The random seed stored in the ESP is refreshed on each reboot ensuring that
       multiple subsequent boots will boot with different seeds. The 'system token' is generated
       randomly once, and then persistently stored in the system's EFI variable storage.

       The systemd-boot-system-token.service unit invokes the bootctl random-seed command, which
       updates the random seed in the ESP, and initializes the 'system token' if it's not
       initialized yet. The service is conditionalized so that it is run only when all of the below
       apply:

       •   A boot loader is used that implements the Boot Loader Interface[1] (which defines the
           'system token' concept).

       •   Either a 'system token' was not set yet, or the boot loader has not passed the OS a
           random seed yet (and thus most likely has been missing the random seed file in the ESP).

       •   The system is not running in a VM environment. This case is explicitly excluded since on
           VM environments the ESP backing storage and EFI variable storage is typically not
           physically separated and hence booting the same OS image in multiple instances would
           replicate both, thus reusing the same random seed and 'system token' among all instances,
           which defeats its purpose. Note that it's still possible to use boot loader random seed
           provisioning in this mode, but the automatic logic implemented by this service has no
           effect then, and the user instead has to manually invoke the bootctl random-seed
           acknowledging these restrictions.

       For further details see bootctl(1), regarding the command this service invokes.

SEE ALSO
       systemd(1), bootctl(1), systemd-boot(7)

NOTES
        1. Boot Loader Interface
           https://systemd.io/BOOT_LOADER_INTERFACE



systemd 249                                                     SYSTEMD-BOOT-SYSTEM-TOKEN.SERVICE(8)