mirror of
https://github.com/LongSoft/UEFITool.git
synced 2025-05-29 14:35:23 -04:00
150 lines
3.3 KiB
Text
150 lines
3.3 KiB
Text
meta:
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id: edk2_vss2
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title: EDK2 VSS2 NVRAM variable storage
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application: EDK2-based UEFI firmware
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file-extension: vss2
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tags:
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- firmware
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license: CC0-1.0
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ks-version: 0.9
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endian: le
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seq:
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- id: signature
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size: 16
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- id: vss2_size
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type: u4
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valid:
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expr: _ > len_vss2_store_header.as<u4> and _ < 0xFFFFFFFF
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- id: format
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type: u1
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- id: state
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type: u1
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- id: reserved
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type: u2
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- id: reserved1
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type: u4
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- id: body
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type: vss2_store_body
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size: vss2_size - len_vss2_store_header
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instances:
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len_vss2_store_header:
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value: 7 * sizeof<u4>
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types:
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vss2_store_body:
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seq:
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- id: variables
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type: vss2_variable
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repeat: until
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repeat-until: _.signature_first != 0xAA or _io.eof
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vss2_variable_attributes:
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seq:
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- id: non_volatile
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type: b1le
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- id: boot_service
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type: b1le
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- id: runtime
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type: b1le
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- id: hw_error_record
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type: b1le
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- id: auth_write
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type: b1le
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- id: time_based_auth
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type: b1le
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- id: append_write
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type: b1le
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- id: reserved
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type: b25le
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vss2_variable:
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seq:
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- id: invoke_offset
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size: 0
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if: offset >= 0
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- id: signature_first
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type: u1
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- id: signature_last
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type: u1
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valid:
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expr: _ == 0x55
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if: signature_first == 0xAA
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- id: state
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type: u1
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if: signature_first == 0xAA
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- id: reserved
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type: u1
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if: signature_first == 0xAA
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- id: attributes
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type: vss2_variable_attributes
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if: signature_first == 0xAA
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- id: len_name
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type: u4
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if: signature_first == 0xAA
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- id: len_data
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type: u4
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if: signature_first == 0xAA
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# vvv Auth variable
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- id: timestamp
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size: 16
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if: signature_first == 0xAA and is_auth
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- id: pubkey_index
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type: u4
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if: signature_first == 0xAA and is_auth
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- id: len_name_auth
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type: u4
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if: signature_first == 0xAA and is_auth
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- id: len_data_auth
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type: u4
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if: signature_first == 0xAA and is_auth
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# ^^^ Auth variable
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- id: vendor_guid
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size: 16
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if: signature_first == 0xAA
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# vvv Auth variable
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- id: name_auth
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size: len_name_auth
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if: signature_first == 0xAA and is_auth
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- id: data_auth
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size: len_data_auth
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if: signature_first == 0xAA and is_auth
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- id: invoke_end_offset_auth
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size: 0
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if: signature_first == 0xAA and is_auth and end_offset_auth >= 0
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- id: alignment_padding_auth
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size: len_alignment_padding_auth
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if: signature_first == 0xAA and is_auth
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# ^^^ Auth variable
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- id: name
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size: len_name
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if: signature_first == 0xAA and not is_auth
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- id: data
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size: len_data
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if: signature_first == 0xAA and not is_auth
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- id: invoke_end_offset
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size: 0
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if: signature_first == 0xAA and not is_auth and end_offset >= 0
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- id: alignment_padding
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size: len_alignment_padding
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if: signature_first == 0xAA and not is_auth
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instances:
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offset:
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value: _io.pos
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end_offset:
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value: _io.pos
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end_offset_auth:
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value: _io.pos
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len_alignment_padding:
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value: (((end_offset - offset)+3) & ~3) - (end_offset - offset)
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len_alignment_padding_auth:
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value: (((end_offset_auth - offset)+3) & ~3) - (end_offset_auth - offset)
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is_valid:
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value: state == 0x7F or state == 0x3F
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is_auth:
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value: (attributes.auth_write or attributes.time_based_auth or attributes.append_write) or (len_name == 0 or len_data == 0)
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len_auth_header:
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value: 60
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len_standard_header:
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value: 32
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