59 lines
2.2 KiB
Plaintext
59 lines
2.2 KiB
Plaintext
import { TPM_ALG, TPM_ST } from './constants.js';
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import { isoUint8Array } from '../../../helpers/iso/index.js';
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/**
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* Cut up a TPM attestation's certInfo into intelligible chunks
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*/
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export function parseCertInfo(certInfo) {
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let pointer = 0;
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const dataView = isoUint8Array.toDataView(certInfo);
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// Get a magic constant
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const magic = dataView.getUint32(pointer);
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pointer += 4;
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// Determine the algorithm used for attestation
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const typeBuffer = dataView.getUint16(pointer);
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pointer += 2;
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const type = TPM_ST[typeBuffer];
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// The name of a parent entity, can be ignored
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const qualifiedSignerLength = dataView.getUint16(pointer);
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pointer += 2;
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const qualifiedSigner = certInfo.slice(pointer, pointer += qualifiedSignerLength);
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// Get the expected hash of `attsToBeSigned`
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const extraDataLength = dataView.getUint16(pointer);
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pointer += 2;
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const extraData = certInfo.slice(pointer, pointer += extraDataLength);
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// Information about the TPM device's internal clock, can be ignored
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const clock = certInfo.slice(pointer, pointer += 8);
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const resetCount = dataView.getUint32(pointer);
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pointer += 4;
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const restartCount = dataView.getUint32(pointer);
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pointer += 4;
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const safe = !!certInfo.slice(pointer, pointer += 1);
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const clockInfo = { clock, resetCount, restartCount, safe };
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// TPM device firmware version
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const firmwareVersion = certInfo.slice(pointer, pointer += 8);
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// Attested Name
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const attestedNameLength = dataView.getUint16(pointer);
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pointer += 2;
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const attestedName = certInfo.slice(pointer, pointer += attestedNameLength);
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const attestedNameDataView = isoUint8Array.toDataView(attestedName);
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// Attested qualified name, can be ignored
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const qualifiedNameLength = dataView.getUint16(pointer);
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pointer += 2;
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const qualifiedName = certInfo.slice(pointer, pointer += qualifiedNameLength);
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const attested = {
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nameAlg: TPM_ALG[attestedNameDataView.getUint16(0)],
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nameAlgBuffer: attestedName.slice(0, 2),
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name: attestedName,
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qualifiedName,
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};
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return {
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magic,
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type,
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qualifiedSigner,
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extraData,
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clockInfo,
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firmwareVersion,
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attested,
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};
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}
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