constellation/coordinator/attestation/aws/validator.go

package aws

import (
	"bytes"
	"encoding/json"
	"fmt"
	"time"

	"github.com/edgelesssys/constellation/coordinator/oid"
)

// https://aws-nitro-enclaves.amazonaws.com/AWS_NitroEnclaves_Root-G1.zip
var awsNitroEnclavesRoot = []byte{
	0x30, 0x82, 0x02, 0x11, 0x30, 0x82, 0x01, 0x96, 0xa0, 0x03, 0x02, 0x01, 0x02, 0x02, 0x11, 0x00,
	0xf9, 0x31, 0x75, 0x68, 0x1b, 0x90, 0xaf, 0xe1, 0x1d, 0x46, 0xcc, 0xb4, 0xe4, 0xe7, 0xf8, 0x56,
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	0x06, 0x03, 0x55, 0x04, 0x0b, 0x0c, 0x03, 0x41, 0x57, 0x53, 0x31, 0x1b, 0x30, 0x19, 0x06, 0x03,
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	0xc1, 0xf3, 0x68, 0x70, 0xe2, 0x9a, 0xda, 0x90, 0xbe, 0x46, 0x38, 0x32, 0x92, 0x73, 0x6e, 0x89,
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	0xea, 0x21, 0x1b, 0x66, 0xe7, 0x52, 0xcf, 0x7d, 0xd1, 0xdd, 0x09, 0x5f, 0x6f, 0x13, 0x70, 0xf4,
	0x17, 0x08, 0x43, 0xd9, 0xdc, 0x10, 0x01, 0x21, 0xe4, 0xcf, 0x63, 0x01, 0x28, 0x09, 0x66, 0x44,
	0x87, 0xc9, 0x79, 0x62, 0x84, 0x30, 0x4d, 0xc5, 0x3f, 0xf4, 0xa3, 0x42, 0x30, 0x40, 0x30, 0x0f,
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	0x1d, 0x06, 0x03, 0x55, 0x1d, 0x0e, 0x04, 0x16, 0x04, 0x14, 0x90, 0x25, 0xb5, 0x0d, 0xd9, 0x05,
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	0x06, 0x03, 0x55, 0x1d, 0x0f, 0x01, 0x01, 0xff, 0x04, 0x04, 0x03, 0x02, 0x01, 0x86, 0x30, 0x0a,
	0x06, 0x08, 0x2a, 0x86, 0x48, 0xce, 0x3d, 0x04, 0x03, 0x03, 0x03, 0x69, 0x00, 0x30, 0x66, 0x02,
	0x31, 0x00, 0xa3, 0x7f, 0x2f, 0x91, 0xa1, 0xc9, 0xbd, 0x5e, 0xe7, 0xb8, 0x62, 0x7c, 0x16, 0x98,
	0xd2, 0x55, 0x03, 0x8e, 0x1f, 0x03, 0x43, 0xf9, 0x5b, 0x63, 0xa9, 0x62, 0x8c, 0x3d, 0x39, 0x80,
	0x95, 0x45, 0xa1, 0x1e, 0xbc, 0xbf, 0x2e, 0x3b, 0x55, 0xd8, 0xae, 0xee, 0x71, 0xb4, 0xc3, 0xd6,
	0xad, 0xf3, 0x02, 0x31, 0x00, 0xa2, 0xf3, 0x9b, 0x16, 0x05, 0xb2, 0x70, 0x28, 0xa5, 0xdd, 0x4b,
	0xa0, 0x69, 0xb5, 0x01, 0x6e, 0x65, 0xb4, 0xfb, 0xde, 0x8f, 0xe0, 0x06, 0x1d, 0x6a, 0x53, 0x19,
	0x7f, 0x9c, 0xda, 0xf5, 0xd9, 0x43, 0xbc, 0x61, 0xfc, 0x2b, 0xeb, 0x03, 0xcb, 0x6f, 0xee, 0x8d,
	0x23, 0x02, 0xf3, 0xdf, 0xf6,
}

type attestationDocument struct {
	ModuleID  string `json:"module_id"`
	Digest    string
	Timestamp int
	Pcrs      map[string]string
	PublicKey []byte `json:"public_key"`
	UserData  []byte `json:"user_data"`
	Nonce     []byte
}

type VerifyFunc func(adBlob []byte, rootCertDer []byte, ts time.Time) (string, error)

type Validator struct {
	oid.AWS
	getVerifiedPayloadAsJson VerifyFunc
}

func NewValidator(getVerifiedPayloadAsJson VerifyFunc) *Validator {
	return &Validator{getVerifiedPayloadAsJson: getVerifiedPayloadAsJson}
}

func (a *Validator) Validate(attDoc []byte, nonce []byte) ([]byte, error) {
	jsonStr, err := a.getVerifiedPayloadAsJson(attDoc, awsNitroEnclavesRoot, time.Now())
	if err != nil {
		return nil, err
	}

	var parsedAttDoc attestationDocument
	if err := json.Unmarshal([]byte(jsonStr), &parsedAttDoc); err != nil {
		return nil, err
	}

	if !bytes.Equal(parsedAttDoc.Nonce, nonce) {
		return nil, fmt.Errorf("validator: failed nonce freshness for nonce: %s", parsedAttDoc.Nonce)
	}

	// TODO: Choose PCRs for validation

	return parsedAttDoc.UserData, nil
}