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This is useful whenever you want to diagnose the current state of UEFI variables, to assert that bootloaders or boot programs (systemd-stub) did their job correctly and set their variables accordingly. In the future, it can enable inspecting SecureBoot keys also.
31 lines
1 KiB
Python
31 lines
1 KiB
Python
from enum import IntEnum
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class EfiVariableAttributes(IntEnum):
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NonVolatile = 0x01
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BootServiceAccess = 0x02
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RuntimeAccess = 0x04
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HardwareErrorRecord = 0x08
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AuthenticatedWriteAccess = 0x10
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TimeBasedAuthenticatedWriteAccess = 0x20
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AppendWrite = 0x40
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EnhancedAuthenticatedAccess = 0x80
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class EfiVariable:
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"""
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An EFI variable represented by its attributes and raw value in bytes.
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Generally, the value is not encoded in UTF-8, but UCS-2 or UTF-16-LE.
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"""
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attributes: EfiVariableAttributes
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value: bytes
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def __init__(self, value: bytes, attributes: bytes):
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self.value = value
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self.attributes = EfiVariableAttributes(attributes)
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def value_as_null_terminated_string(self, encoding: str = 'utf-16-le'):
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"""
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Most often, variables are encoded with a null-terminated \x00.
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This function gives you the string in a default encoding of UTF-16-LE
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stripped of the null terminator.
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"""
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return self.value.decode(encoding).rstrip('\x00')
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