cmd/swarm, swarm: added access control functionality (#17404)

Co-authored-by: Janos Guljas <janos@resenje.org>
Co-authored-by: Anton Evangelatov <anton.evangelatov@gmail.com>
Co-authored-by: Balint Gabor <balint.g@gmail.com>

1 files changed, 468 insertions, 0 deletions

diff --git a/swarm/api/act.go b/swarm/api/act.go
new file mode 100644
index 000000000..b1a594783
--- /dev/null
+++ b/swarm/api/act.go
@@ -0,0 +1,468 @@
+package api
+
+import (
+	"context"
+	"crypto/ecdsa"
+	"crypto/rand"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"strings"
+	"time"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/crypto/ecies"
+	"github.com/ethereum/go-ethereum/crypto/sha3"
+	"github.com/ethereum/go-ethereum/swarm/log"
+	"github.com/ethereum/go-ethereum/swarm/sctx"
+	"github.com/ethereum/go-ethereum/swarm/storage"
+	"golang.org/x/crypto/scrypt"
+	cli "gopkg.in/urfave/cli.v1"
+)
+
+var (
+	ErrDecrypt                = errors.New("cant decrypt - forbidden")
+	ErrUnknownAccessType      = errors.New("unknown access type (or not implemented)")
+	ErrDecryptDomainForbidden = errors.New("decryption request domain forbidden - can only decrypt on localhost")
+	AllowedDecryptDomains     = []string{
+		"localhost",
+		"127.0.0.1",
+	}
+)
+
+const EMPTY_CREDENTIALS = ""
+
+type AccessEntry struct {
+	Type      AccessType
+	Publisher string
+	Salt      []byte
+	Act       string
+	KdfParams *KdfParams
+}
+
+type DecryptFunc func(*ManifestEntry) error
+
+func (a *AccessEntry) MarshalJSON() (out []byte, err error) {
+
+	return json.Marshal(struct {
+		Type      AccessType `json:"type,omitempty"`
+		Publisher string     `json:"publisher,omitempty"`
+		Salt      string     `json:"salt,omitempty"`
+		Act       string     `json:"act,omitempty"`
+		KdfParams *KdfParams `json:"kdf_params,omitempty"`
+	}{
+		Type:      a.Type,
+		Publisher: a.Publisher,
+		Salt:      hex.EncodeToString(a.Salt),
+		Act:       a.Act,
+		KdfParams: a.KdfParams,
+	})
+
+}
+
+func (a *AccessEntry) UnmarshalJSON(value []byte) error {
+	v := struct {
+		Type      AccessType `json:"type,omitempty"`
+		Publisher string     `json:"publisher,omitempty"`
+		Salt      string     `json:"salt,omitempty"`
+		Act       string     `json:"act,omitempty"`
+		KdfParams *KdfParams `json:"kdf_params,omitempty"`
+	}{}
+
+	err := json.Unmarshal(value, &v)
+	if err != nil {
+		return err
+	}
+	a.Act = v.Act
+	a.KdfParams = v.KdfParams
+	a.Publisher = v.Publisher
+	a.Salt, err = hex.DecodeString(v.Salt)
+	if err != nil {
+		return err
+	}
+	if len(a.Salt) != 32 {
+		return errors.New("salt should be 32 bytes long")
+	}
+	a.Type = v.Type
+	return nil
+}
+
+type KdfParams struct {
+	N int `json:"n"`
+	P int `json:"p"`
+	R int `json:"r"`
+}
+
+type AccessType string
+
+const AccessTypePass = AccessType("pass")
+const AccessTypePK = AccessType("pk")
+const AccessTypeACT = AccessType("act")
+
+func NewAccessEntryPassword(salt []byte, kdfParams *KdfParams) (*AccessEntry, error) {
+	if len(salt) != 32 {
+		return nil, fmt.Errorf("salt should be 32 bytes long")
+	}
+	return &AccessEntry{
+		Type:      AccessTypePass,
+		Salt:      salt,
+		KdfParams: kdfParams,
+	}, nil
+}
+
+func NewAccessEntryPK(publisher string, salt []byte) (*AccessEntry, error) {
+	if len(publisher) != 66 {
+		return nil, fmt.Errorf("publisher should be 66 characters long, got %d", len(publisher))
+	}
+	if len(salt) != 32 {
+		return nil, fmt.Errorf("salt should be 32 bytes long")
+	}
+	return &AccessEntry{
+		Type:      AccessTypePK,
+		Publisher: publisher,
+		Salt:      salt,
+	}, nil
+}
+
+func NewAccessEntryACT(publisher string, salt []byte, act string) (*AccessEntry, error) {
+	if len(salt) != 32 {
+		return nil, fmt.Errorf("salt should be 32 bytes long")
+	}
+	if len(publisher) != 66 {
+		return nil, fmt.Errorf("publisher should be 66 characters long")
+	}
+
+	return &AccessEntry{
+		Type:      AccessTypeACT,
+		Publisher: publisher,
+		Salt:      salt,
+		Act:       act,
+	}, nil
+}
+
+func NOOPDecrypt(*ManifestEntry) error {
+	return nil
+}
+
+var DefaultKdfParams = NewKdfParams(262144, 1, 8)
+
+func NewKdfParams(n, p, r int) *KdfParams {
+
+	return &KdfParams{
+		N: n,
+		P: p,
+		R: r,
+	}
+}
+
+// NewSessionKeyPassword creates a session key based on a shared secret (password) and the given salt
+// and kdf parameters in the access entry
+func NewSessionKeyPassword(password string, accessEntry *AccessEntry) ([]byte, error) {
+	if accessEntry.Type != AccessTypePass {
+		return nil, errors.New("incorrect access entry type")
+	}
+	return scrypt.Key(
+		[]byte(password),
+		accessEntry.Salt,
+		accessEntry.KdfParams.N,
+		accessEntry.KdfParams.R,
+		accessEntry.KdfParams.P,
+		32,
+	)
+}
+
+// NewSessionKeyPK creates a new ACT Session Key using an ECDH shared secret for the given key pair and the given salt value
+func NewSessionKeyPK(private *ecdsa.PrivateKey, public *ecdsa.PublicKey, salt []byte) ([]byte, error) {
+	granteePubEcies := ecies.ImportECDSAPublic(public)
+	privateKey := ecies.ImportECDSA(private)
+
+	bytes, err := privateKey.GenerateShared(granteePubEcies, 16, 16)
+	if err != nil {
+		return nil, err
+	}
+	bytes = append(salt, bytes...)
+	sessionKey := crypto.Keccak256(bytes)
+	return sessionKey, nil
+}
+
+func (a *API) NodeSessionKey(privateKey *ecdsa.PrivateKey, publicKey *ecdsa.PublicKey, salt []byte) ([]byte, error) {
+	return NewSessionKeyPK(privateKey, publicKey, salt)
+}
+func (a *API) doDecrypt(ctx context.Context, credentials string, pk *ecdsa.PrivateKey) DecryptFunc {
+	return func(m *ManifestEntry) error {
+		if m.Access == nil {
+			return nil
+		}
+
+		allowed := false
+		requestDomain := sctx.GetHost(ctx)
+		for _, v := range AllowedDecryptDomains {
+			if strings.Contains(requestDomain, v) {
+				allowed = true
+			}
+		}
+
+		if !allowed {
+			return ErrDecryptDomainForbidden
+		}
+
+		switch m.Access.Type {
+		case "pass":
+			if credentials != "" {
+				key, err := NewSessionKeyPassword(credentials, m.Access)
+				if err != nil {
+					return err
+				}
+
+				ref, err := hex.DecodeString(m.Hash)
+				if err != nil {
+					return err
+				}
+
+				enc := NewRefEncryption(len(ref) - 8)
+				decodedRef, err := enc.Decrypt(ref, key)
+				if err != nil {
+					return ErrDecrypt
+				}
+
+				m.Hash = hex.EncodeToString(decodedRef)
+				m.Access = nil
+				return nil
+			}
+			return ErrDecrypt
+		case "pk":
+			publisherBytes, err := hex.DecodeString(m.Access.Publisher)
+			if err != nil {
+				return ErrDecrypt
+			}
+			publisher, err := crypto.DecompressPubkey(publisherBytes)
+			if err != nil {
+				return ErrDecrypt
+			}
+			key, err := a.NodeSessionKey(pk, publisher, m.Access.Salt)
+			if err != nil {
+				return ErrDecrypt
+			}
+			ref, err := hex.DecodeString(m.Hash)
+			if err != nil {
+				return err
+			}
+
+			enc := NewRefEncryption(len(ref) - 8)
+			decodedRef, err := enc.Decrypt(ref, key)
+			if err != nil {
+				return ErrDecrypt
+			}
+
+			m.Hash = hex.EncodeToString(decodedRef)
+			m.Access = nil
+			return nil
+		case "act":
+			publisherBytes, err := hex.DecodeString(m.Access.Publisher)
+			if err != nil {
+				return ErrDecrypt
+			}
+			publisher, err := crypto.DecompressPubkey(publisherBytes)
+			if err != nil {
+				return ErrDecrypt
+			}
+
+			sessionKey, err := a.NodeSessionKey(pk, publisher, m.Access.Salt)
+			if err != nil {
+				return ErrDecrypt
+			}
+
+			hasher := sha3.NewKeccak256()
+			hasher.Write(append(sessionKey, 0))
+			lookupKey := hasher.Sum(nil)
+
+			hasher.Reset()
+
+			hasher.Write(append(sessionKey, 1))
+			accessKeyDecryptionKey := hasher.Sum(nil)
+
+			lk := hex.EncodeToString(lookupKey)
+			list, err := a.GetManifestList(ctx, NOOPDecrypt, storage.Address(common.Hex2Bytes(m.Access.Act)), lk)
+
+			found := ""
+			for _, v := range list.Entries {
+				if v.Path == lk {
+					found = v.Hash
+				}
+			}
+
+			if found == "" {
+				return ErrDecrypt
+			}
+
+			v, err := hex.DecodeString(found)
+			if err != nil {
+				return err
+			}
+			enc := NewRefEncryption(len(v) - 8)
+			decodedRef, err := enc.Decrypt(v, accessKeyDecryptionKey)
+			if err != nil {
+				return ErrDecrypt
+			}
+
+			ref, err := hex.DecodeString(m.Hash)
+			if err != nil {
+				return err
+			}
+
+			enc = NewRefEncryption(len(ref) - 8)
+			decodedMainRef, err := enc.Decrypt(ref, decodedRef)
+			if err != nil {
+				return ErrDecrypt
+			}
+			m.Hash = hex.EncodeToString(decodedMainRef)
+			m.Access = nil
+			return nil
+		}
+		return ErrUnknownAccessType
+	}
+}
+
+func GenerateAccessControlManifest(ctx *cli.Context, ref string, accessKey []byte, ae *AccessEntry) (*Manifest, error) {
+	refBytes, err := hex.DecodeString(ref)
+	if err != nil {
+		return nil, err
+	}
+	// encrypt ref with accessKey
+	enc := NewRefEncryption(len(refBytes))
+	encrypted, err := enc.Encrypt(refBytes, accessKey)
+	if err != nil {
+		return nil, err
+	}
+
+	m := &Manifest{
+		Entries: []ManifestEntry{
+			{
+				Hash:        hex.EncodeToString(encrypted),
+				ContentType: ManifestType,
+				ModTime:     time.Now(),
+				Access:      ae,
+			},
+		},
+	}
+
+	return m, nil
+}
+
+func DoPKNew(ctx *cli.Context, privateKey *ecdsa.PrivateKey, granteePublicKey string, salt []byte) (sessionKey []byte, ae *AccessEntry, err error) {
+	if granteePublicKey == "" {
+		return nil, nil, errors.New("need a grantee Public Key")
+	}
+	b, err := hex.DecodeString(granteePublicKey)
+	if err != nil {
+		log.Error("error decoding grantee public key", "err", err)
+		return nil, nil, err
+	}
+
+	granteePub, err := crypto.DecompressPubkey(b)
+	if err != nil {
+		log.Error("error decompressing grantee public key", "err", err)
+		return nil, nil, err
+	}
+
+	sessionKey, err = NewSessionKeyPK(privateKey, granteePub, salt)
+	if err != nil {
+		log.Error("error getting session key", "err", err)
+		return nil, nil, err
+	}
+
+	ae, err = NewAccessEntryPK(hex.EncodeToString(crypto.CompressPubkey(&privateKey.PublicKey)), salt)
+	if err != nil {
+		log.Error("error generating access entry", "err", err)
+		return nil, nil, err
+	}
+
+	return sessionKey, ae, nil
+}
+
+func DoACTNew(ctx *cli.Context, privateKey *ecdsa.PrivateKey, salt []byte, grantees []string) (accessKey []byte, ae *AccessEntry, actManifest *Manifest, err error) {
+	if len(grantees) == 0 {
+		return nil, nil, nil, errors.New("did not get any grantee public keys")
+	}
+
+	publisherPub := hex.EncodeToString(crypto.CompressPubkey(&privateKey.PublicKey))
+	grantees = append(grantees, publisherPub)
+
+	accessKey = make([]byte, 32)
+	if _, err := io.ReadFull(rand.Reader, salt); err != nil {
+		panic("reading from crypto/rand failed: " + err.Error())
+	}
+	if _, err := io.ReadFull(rand.Reader, accessKey); err != nil {
+		panic("reading from crypto/rand failed: " + err.Error())
+	}
+
+	lookupPathEncryptedAccessKeyMap := make(map[string]string)
+	i := 0
+	for _, v := range grantees {
+		i++
+		if v == "" {
+			return nil, nil, nil, errors.New("need a grantee Public Key")
+		}
+		b, err := hex.DecodeString(v)
+		if err != nil {
+			log.Error("error decoding grantee public key", "err", err)
+			return nil, nil, nil, err
+		}
+
+		granteePub, err := crypto.DecompressPubkey(b)
+		if err != nil {
+			log.Error("error decompressing grantee public key", "err", err)
+			return nil, nil, nil, err
+		}
+		sessionKey, err := NewSessionKeyPK(privateKey, granteePub, salt)
+
+		hasher := sha3.NewKeccak256()
+		hasher.Write(append(sessionKey, 0))
+		lookupKey := hasher.Sum(nil)
+
+		hasher.Reset()
+		hasher.Write(append(sessionKey, 1))
+
+		accessKeyEncryptionKey := hasher.Sum(nil)
+
+		enc := NewRefEncryption(len(accessKey))
+		encryptedAccessKey, err := enc.Encrypt(accessKey, accessKeyEncryptionKey)
+
+		lookupPathEncryptedAccessKeyMap[hex.EncodeToString(lookupKey)] = hex.EncodeToString(encryptedAccessKey)
+	}
+
+	m := &Manifest{
+		Entries: []ManifestEntry{},
+	}
+
+	for k, v := range lookupPathEncryptedAccessKeyMap {
+		m.Entries = append(m.Entries, ManifestEntry{
+			Path:        k,
+			Hash:        v,
+			ContentType: "text/plain",
+		})
+	}
+
+	ae, err = NewAccessEntryACT(hex.EncodeToString(crypto.CompressPubkey(&privateKey.PublicKey)), salt, "")
+	if err != nil {
+		return nil, nil, nil, err
+	}
+
+	return accessKey, ae, m, nil
+}
+
+func DoPasswordNew(ctx *cli.Context, password string, salt []byte) (sessionKey []byte, ae *AccessEntry, err error) {
+	ae, err = NewAccessEntryPassword(salt, DefaultKdfParams)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	sessionKey, err = NewSessionKeyPassword(password, ae)
+	if err != nil {
+		return nil, nil, err
+	}
+	return sessionKey, ae, nil
+}