From b009bac5fb2e6a21e65e01429070814360a0ae30 Mon Sep 17 00:00:00 2001 From: Samuel Hawksby-Robinson Date: Thu, 11 Feb 2021 17:07:11 +0000 Subject: [PATCH] Switched encryption of payload and keys to AES Added Encrypted field to the protobuf --- protocol/common/crypto.go | 16 ++++- protocol/messenger.go | 91 ++++++++++++++++++++------- protocol/messenger_maps.go | 10 +++ protocol/messenger_test.go | 78 +++++++++++++++++++++++ protocol/protobuf/chat_identity.pb.go | 66 ++++++++++--------- protocol/protobuf/chat_identity.proto | 3 + 6 files changed, 213 insertions(+), 51 deletions(-) diff --git a/protocol/common/crypto.go b/protocol/common/crypto.go index cd1e802c6..7900ae974 100644 --- a/protocol/common/crypto.go +++ b/protocol/common/crypto.go @@ -9,11 +9,17 @@ import ( "golang.org/x/crypto/sha3" + "github.com/ethereum/go-ethereum/crypto/ecies" + "github.com/status-im/status-go/eth-node/crypto" "github.com/status-im/status-go/eth-node/types" ) -const nonceLength = 12 +const( + nonceLength = 12 + defaultECHDSharedKeyLength = 16 + defaultECHDMACLength = 16 +) var ErrInvalidCiphertextLength = errors.New("invalid cyphertext length") @@ -86,3 +92,11 @@ func HexToPubkey(pk string) (*ecdsa.PublicKey, error) { } return crypto.UnmarshalPubkey(bytes) } + +func MakeECDHSharedKey(yourPrivateKey *ecdsa.PrivateKey, theirPubKey *ecdsa.PublicKey) ([]byte, error) { + return ecies.ImportECDSA(yourPrivateKey).GenerateShared( + ecies.ImportECDSAPublic(theirPubKey), + defaultECHDSharedKeyLength, + defaultECHDMACLength, + ) +} diff --git a/protocol/messenger.go b/protocol/messenger.go index 9dffb77cf..b3f092d32 100644 --- a/protocol/messenger.go +++ b/protocol/messenger.go @@ -5,7 +5,6 @@ import ( "context" "crypto/ecdsa" crand "crypto/rand" - "crypto/x509" "database/sql" "encoding/hex" "fmt" @@ -23,8 +22,6 @@ import ( "github.com/davecgh/go-spew/spew" "github.com/golang/protobuf/proto" - "github.com/ethereum/go-ethereum/crypto/ecies" - "github.com/status-im/status-go/appdatabase" "github.com/status-im/status-go/appmetrics" "github.com/status-im/status-go/connection" @@ -780,6 +777,7 @@ func (m *Messenger) attachIdentityImagesToChatIdentity(context chatContext, ci * return err } + // TODO remove the use of ProfilePicturesVisibility and create a new settings field, if s.ProfilePicturesVisibility == accounts.ProfilePicturesVisibilityNone { m.logger.Info(fmt.Sprintf("settings.ProfilePicturesVisibility is set to '%d', skipping attaching IdentityImages", s.ProfilePicturesVisibility)) return nil @@ -832,46 +830,95 @@ func (m *Messenger) attachIdentityImagesToChatIdentity(context chatContext, ci * return nil } -func (m *Messenger) encryptIdentityImagesWithContactPubKeys(ciis map[string]*protobuf.IdentityImage) error { - // Make ephemeral key - pk, err := crypto.GenerateKey() +func (m *Messenger) encryptIdentityImagesWithContactPubKeys(iis map[string]*protobuf.IdentityImage) (err error) { + // Make AES key + AESKey := make([]byte, 32) + _, err = crand.Read(AESKey) if err != nil { return err } - // Marshal the ephemeral private key into bytes - mpk, err := x509.MarshalECPrivateKey(pk) - if err != nil { - return err - } - - for _, ii := range ciis { - // Encrypt image payloads with the ephemeral public key - encryptedPayload, err := ecies.Encrypt(crand.Reader, ecies.ImportECDSAPublic(&pk.PublicKey), ii.Payload, nil, nil) + for _, ii := range iis { + // Encrypt image payload with the AES key + encryptedPayload, err := common.Encrypt(ii.Payload, AESKey, crand.Reader) if err != nil { return err } // Overwrite the unencrypted payload with the newly encrypted payload ii.Payload = encryptedPayload - for _, c := range m.allContacts { + ii.Encrypted = true + m.allContacts.Range(func(contactID string, c *Contact) (shouldContinue bool) { if !c.IsAdded() { - continue + return false } pubK, err := c.PublicKey() if err != nil { - return err + return false + } + // Generate a Diffie-Helman (DH) between the sender private key and the recipient's public key + sharedKey, err := common.MakeECDHSharedKey(m.identity, pubK) + if err != nil { + return false } - // Encrypt the marshalled ephemeral private key with the contact's public key - empk, err := ecies.Encrypt(crand.Reader, ecies.ImportECDSAPublic(pubK), mpk, nil, nil) + // Encrypt the main AES key with AES encryption using the DH key + eAESKey, err := common.Encrypt(AESKey, sharedKey, crand.Reader) + if err != nil { + return false + } + + // Append the the encrypted main AES key to the IdentityImage's EncryptionKeys slice. + ii.EncryptionKeys = append(ii.EncryptionKeys, eAESKey) + + return true + }) + + if err != nil { + return err + } + } + + return nil +} + +func (m *Messenger) decryptIdentityImagesWithIdentityPrivateKey(iis map[string]*protobuf.IdentityImage, senderPubKey *ecdsa.PublicKey) error { +image: + for _, ii := range iis { + for _, empk := range ii.EncryptionKeys { + // Generate a Diffie-Helman (DH) between the recipient's private key and the sender's public key + sharedKey, err := common.MakeECDHSharedKey(m.identity, senderPubKey) if err != nil { return err } - // Append the the encrypted private key to the IdentityImage's EncryptionKeys slice. - ii.EncryptionKeys = append(ii.EncryptionKeys, empk) + // Decrypt the main encryption AES key with AES encryption using the DH key + dAESKey, err := common.Decrypt(empk, sharedKey) + if err != nil { + if err.Error() == "cipher: message authentication failed" { + continue + } + return err + } + if dAESKey == nil{ + return errors.New("decrypting the payload encryption key resulted in no error and a nil key") + } + + // Decrypt the payload with the newly decrypted main encryption AES key + payload, err := common.Decrypt(ii.Payload, dAESKey) + if err != nil { + return err + } + if payload == nil { + // TODO should this be a logger warn? A payload could theoretically be validly empty + return errors.New("decrypting the payload resulted in no error and a nil payload") + } + + // Overwrite the payload with the decrypted data + ii.Payload = payload + ii.Encrypted = false // TODO handle the encryption state in the consuming code + continue image } } diff --git a/protocol/messenger_maps.go b/protocol/messenger_maps.go index ffb615ed9..a51735a63 100644 --- a/protocol/messenger_maps.go +++ b/protocol/messenger_maps.go @@ -79,6 +79,16 @@ func (cm *contactMap) Delete(contactID string) { cm.sm.Delete(contactID) } +func (cm *contactMap) Len() int { + count := 0 + cm.Range(func(key string, value *Contact) (shouldContinue bool) { + count++ + return true + }) + + return count +} + /* |-------------------------------------------------------------------------- | systemMessageTranslationsMap diff --git a/protocol/messenger_test.go b/protocol/messenger_test.go index 0c6ff9849..5fe6a39fa 100644 --- a/protocol/messenger_test.go +++ b/protocol/messenger_test.go @@ -2564,3 +2564,81 @@ func (s *MessengerSuite) TestPublicMessageOnCommunityChat() { s.Require().Error(err) s.Require().Equal(ErrMessageForWrongChatType, err) } + +func (s *MessengerSuite) TestEncryptDecryptIdentityImagesWithContactPubKeys() { + smPayload := "hello small image" + lgPayload := "hello large image" + + ci := protobuf.ChatIdentity{ + Clock: uint64(time.Now().Unix()), + Images: map[string]*protobuf.IdentityImage{ + "small": { + Payload: []byte(smPayload), + }, + "large": { + Payload: []byte(lgPayload), + }, + }, + } + + // Make contact keys and Contacts, set the Contacts to added + var contactKeys []*ecdsa.PrivateKey + for i:=0; i < 10; i++ { + contactKey, err := crypto.GenerateKey() + s.Require().NoError(err) + contactKeys = append(contactKeys, contactKey) + + contact, err := BuildContactFromPublicKey(&contactKey.PublicKey) + s.Require().NoError(err) + + contact.SystemTags = append(contact.SystemTags, contactAdded) + s.m.allContacts.Store(contact.ID, contact) + } + + // Test encryptIdentityImagesWithContactPubKeys + err := s.m.encryptIdentityImagesWithContactPubKeys(ci.Images) + s.Require().NoError(err) + + for _, ii := range ci.Images { + s.Require().Equal(s.m.allContacts.Len, len(ii.EncryptionKeys)) + } + s.Require().NotEqual([]byte(smPayload), ci.Images["small"].Payload) + s.Require().NotEqual([]byte(lgPayload), ci.Images["large"].Payload) + + // Switch messenger identities + sender := s.m.identity + s.m.identity = contactKeys[2] + + // Test decryptIdentityImagesWithIdentityPrivateKey + err = s.m.decryptIdentityImagesWithIdentityPrivateKey(ci.Images, &sender.PublicKey) + s.Require().NoError(err) + + s.Require().Equal(smPayload, string(ci.Images["small"].Payload)) + s.Require().Equal(lgPayload, string(ci.Images["large"].Payload)) + + // RESET Messenger identity, Contacts and IdentityImage.EncryptionKeys + s.m.identity = sender + s.m.allContacts = nil + ci.Images["small"].EncryptionKeys = nil + ci.Images["large"].EncryptionKeys = nil + + // Test encryptIdentityImagesWithContactPubKeys with no contacts + err = s.m.encryptIdentityImagesWithContactPubKeys(ci.Images) + s.Require().NoError(err) + + for _, ii := range ci.Images { + s.Require().Equal(0, len(ii.EncryptionKeys)) + } + s.Require().NotEqual([]byte(smPayload), ci.Images["small"].Payload) + s.Require().NotEqual([]byte(lgPayload), ci.Images["large"].Payload) + + // Switch messenger identities + s.m.identity = contactKeys[2] + + // Test decryptIdentityImagesWithIdentityPrivateKey with no valid identity + err = s.m.decryptIdentityImagesWithIdentityPrivateKey(ci.Images, &sender.PublicKey) + s.Require().NoError(err) + + s.Require().NotEqual([]byte(smPayload), ci.Images["small"].Payload) + s.Require().NotEqual([]byte(lgPayload), ci.Images["large"].Payload) +} diff --git a/protocol/protobuf/chat_identity.pb.go b/protocol/protobuf/chat_identity.pb.go index 8563d18bc..03d80a8ae 100644 --- a/protocol/protobuf/chat_identity.pb.go +++ b/protocol/protobuf/chat_identity.pb.go @@ -149,7 +149,9 @@ type IdentityImage struct { // image_type signals the image type and method of parsing the payload ImageType ImageType `protobuf:"varint,3,opt,name=image_type,json=imageType,proto3,enum=protobuf.ImageType" json:"image_type,omitempty"` // encryption_keys is a list of encrypted keys that can be used to decrypted an encrypted payload - EncryptionKeys [][]byte `protobuf:"bytes,4,rep,name=encryption_keys,json=encryptionKeys,proto3" json:"encryption_keys,omitempty"` + EncryptionKeys [][]byte `protobuf:"bytes,4,rep,name=encryption_keys,json=encryptionKeys,proto3" json:"encryption_keys,omitempty"` + // encrypted signals the encryption state of the payload, default is false. + Encrypted bool `protobuf:"varint,5,opt,name=encrypted,proto3" json:"encrypted,omitempty"` XXX_NoUnkeyedLiteral struct{} `json:"-"` XXX_unrecognized []byte `json:"-"` XXX_sizecache int32 `json:"-"` @@ -208,6 +210,13 @@ func (m *IdentityImage) GetEncryptionKeys() [][]byte { return nil } +func (m *IdentityImage) GetEncrypted() bool { + if m != nil { + return m.Encrypted + } + return false +} + func init() { proto.RegisterEnum("protobuf.IdentityImage_SourceType", IdentityImage_SourceType_name, IdentityImage_SourceType_value) proto.RegisterType((*ChatIdentity)(nil), "protobuf.ChatIdentity") @@ -220,31 +229,32 @@ func init() { } var fileDescriptor_7a652489000a5879 = []byte{ - 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