forked from cwtch.im/cwtch
321 lines
9.1 KiB
Go
321 lines
9.1 KiB
Go
package model
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import (
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"crypto/rand"
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"crypto/rsa"
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"cwtch.im/cwtch/protocol"
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"encoding/asn1"
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"errors"
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"git.openprivacy.ca/openprivacy/libricochet-go/utils"
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"github.com/golang/protobuf/proto"
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"golang.org/x/crypto/ed25519"
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"io"
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"sync"
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"time"
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)
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// PublicProfile is a local copy of a CwtchIdentity
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type PublicProfile struct {
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Name string
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Ed25519PublicKey ed25519.PublicKey
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Trusted bool
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Blocked bool
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Onion string
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}
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// Profile encapsulates all the attributes necessary to be a Cwtch Peer.
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type Profile struct {
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PublicProfile
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Contacts map[string]*PublicProfile
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Ed25519PrivateKey ed25519.PrivateKey
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OnionPrivateKey *rsa.PrivateKey
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Groups map[string]*Group
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lock sync.Mutex
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}
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// GenerateNewProfile creates a new profile, with new encryption and signing keys, and a profile name.
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func GenerateNewProfile(name string) *Profile {
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p := new(Profile)
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p.Name = name
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pub, priv, _ := ed25519.GenerateKey(rand.Reader)
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p.Ed25519PublicKey = pub
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p.Ed25519PrivateKey = priv
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p.OnionPrivateKey, _ = utils.GeneratePrivateKey()
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// DER Encode the Public Key
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publicKeyBytes, _ := asn1.Marshal(rsa.PublicKey{
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N: p.OnionPrivateKey.PublicKey.N,
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E: p.OnionPrivateKey.PublicKey.E,
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})
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p.Onion = utils.GetTorHostname(publicKeyBytes)
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p.Contacts = make(map[string]*PublicProfile)
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p.Contacts[p.Onion] = &p.PublicProfile
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p.Groups = make(map[string]*Group)
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return p
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}
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// GetCwtchIdentityPacket returns the wire message for conveying this profiles identity.
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func (p *Profile) GetCwtchIdentityPacket() (message []byte) {
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ci := &protocol.CwtchIdentity{
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Name: p.Name,
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Ed25519PublicKey: p.Ed25519PublicKey,
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}
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cpp := &protocol.CwtchPeerPacket{
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CwtchIdentify: ci,
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}
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message, err := proto.Marshal(cpp)
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utils.CheckError(err)
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return
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}
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// AddCwtchIdentity takes a wire message and if it is a CwtchIdentity message adds the identity as a contact
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// otherwise returns an error
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func (p *Profile) AddCwtchIdentity(onion string, ci *protocol.CwtchIdentity) {
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p.AddContact(onion, &PublicProfile{Name: ci.GetName(), Ed25519PublicKey: ci.GetEd25519PublicKey(), Onion: onion})
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}
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// AddContact allows direct manipulation of cwtch contacts
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func (p *Profile) AddContact(onion string, profile *PublicProfile) {
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p.lock.Lock()
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p.Contacts[onion] = profile
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p.lock.Unlock()
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}
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// RejectInvite rejects and removes a group invite
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func (p *Profile) RejectInvite(groupID string) {
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p.lock.Lock()
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delete(p.Groups, groupID)
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p.lock.Unlock()
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}
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// AcceptInvite accepts a group invite
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func (p *Profile) AcceptInvite(groupID string) (err error) {
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p.lock.Lock()
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defer p.lock.Unlock()
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group, ok := p.Groups[groupID]
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if ok {
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group.Accepted = true
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} else {
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err = errors.New("group does not exist")
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}
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return
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}
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// GetGroups returns an unordered list of group IDs associated with this profile.
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func (p *Profile) GetGroups() []string {
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p.lock.Lock()
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defer p.lock.Unlock()
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var keys []string
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for onion := range p.Groups {
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keys = append(keys, onion)
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}
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return keys
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}
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// GetContacts returns an unordered list of contact onions associated with this profile.
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func (p *Profile) GetContacts() []string {
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p.lock.Lock()
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defer p.lock.Unlock()
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var keys []string
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for onion := range p.Contacts {
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if onion != p.Onion {
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keys = append(keys, onion)
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}
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}
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return keys
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}
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// BlockPeer blocks a contact
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func (p *Profile) BlockPeer(onion string) (err error) {
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p.lock.Lock()
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defer p.lock.Unlock()
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contact, ok := p.Contacts[onion]
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if ok {
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contact.Blocked = true
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} else {
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err = errors.New("peer does not exist")
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}
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return
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}
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// TrustPeer sets a contact to trusted
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func (p *Profile) TrustPeer(onion string) (err error) {
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p.lock.Lock()
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defer p.lock.Unlock()
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contact, ok := p.Contacts[onion]
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if ok {
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contact.Trusted = true
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} else {
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err = errors.New("peer does not exist")
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}
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return
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}
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// IsBlocked returns true if the contact has been blocked, false otherwise
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func (p *Profile) IsBlocked(onion string) bool {
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contact, ok := p.GetContact(onion)
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if ok {
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return contact.Blocked
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}
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return false
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}
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// GetContact returns a contact if the profile has it
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func (p *Profile) GetContact(onion string) (*PublicProfile, bool) {
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p.lock.Lock()
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defer p.lock.Unlock()
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contact, ok := p.Contacts[onion]
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return contact, ok
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}
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// VerifyGroupMessage confirms the authenticity of a message given an onion, message and signature.
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func (p *Profile) VerifyGroupMessage(onion string, groupID string, message string, timestamp int32, ciphertext []byte, signature []byte) bool {
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group := p.GetGroupByGroupID(groupID)
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if group == nil {
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return false
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}
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if onion == p.Onion {
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m := groupID + group.GroupServer + string(ciphertext)
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return ed25519.Verify(p.Ed25519PublicKey, []byte(m), signature)
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}
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contact, found := p.GetContact(onion)
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if found {
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m := groupID + group.GroupServer + string(ciphertext)
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return ed25519.Verify(contact.Ed25519PublicKey, []byte(m), signature)
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}
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return false
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}
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// SignMessage takes a given message and returns an Ed21159 signature
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func (p *Profile) SignMessage(message string) []byte {
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sig := ed25519.Sign(p.Ed25519PrivateKey, []byte(message))
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return sig
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}
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//StartGroup when given a server, creates a new Group under this profile and returns the group id an a precomputed
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// invite which can be sent on the wire.
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func (p *Profile) StartGroup(server string) (groupID string, invite []byte, err error) {
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group := NewGroup(server)
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groupID = group.GroupID
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signedGroupID := p.SignMessage(groupID + server)
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group.SignGroup(signedGroupID)
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invite, err = group.Invite()
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p.lock.Lock()
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defer p.lock.Unlock()
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p.Groups[group.GroupID] = group
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return
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}
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// GetGroupByGroupID a pointer to a Group by the group Id, returns nil if no group found.
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func (p *Profile) GetGroupByGroupID(groupID string) (g *Group) {
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p.lock.Lock()
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defer p.lock.Unlock()
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g = p.Groups[groupID]
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return
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}
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// ProcessInvite adds a new group invite to the profile.
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func (p *Profile) ProcessInvite(gci *protocol.GroupChatInvite, peerHostname string) {
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group := new(Group)
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group.GroupID = gci.GetGroupName()
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group.SignedGroupID = gci.GetSignedGroupId()
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copy(group.GroupKey[:], gci.GetGroupSharedKey()[:])
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group.GroupServer = gci.GetServerHost()
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group.Accepted = false
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group.Owner = peerHostname
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p.AddGroup(group)
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}
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// AddGroup is a convenience method for adding a group to a profile.
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func (p *Profile) AddGroup(group *Group) {
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existingGroup, exists := p.Groups[group.GroupID]
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if !exists {
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owner, ok := p.GetContact(group.Owner)
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if ok {
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valid := ed25519.Verify(owner.Ed25519PublicKey, []byte(group.GroupID+group.GroupServer), group.SignedGroupID)
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if valid {
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p.lock.Lock()
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defer p.lock.Unlock()
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p.Groups[group.GroupID] = group
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}
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}
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} else if exists && existingGroup.Owner == group.Owner {
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p.lock.Lock()
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defer p.lock.Unlock()
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p.Groups[group.GroupID] = group
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}
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// If we are sent an invite or group update by someone who is not an owner
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// then we reject the group.
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}
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// AttemptDecryption takes a ciphertext and signature and attempts to decrypt it under known groups.
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func (p *Profile) AttemptDecryption(ciphertext []byte, signature []byte) (bool, *Message) {
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for _, group := range p.Groups {
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success, dgm := group.DecryptMessage(ciphertext)
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if success {
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// Assert that we know the owner of the group
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owner, ok := p.Contacts[group.Owner]
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if ok {
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valid := ed25519.Verify(owner.Ed25519PublicKey, []byte(group.GroupID+group.GroupServer), dgm.SignedGroupId)
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// If we can decrypt the message, but the group id is wrong that means that
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// this message is from someone who was not invited to the group.
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// As such this group has been compromised, probably by one of the other members.
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// We set the flag to be handled by the UX and reject the message.
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if !valid {
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group.Compromised()
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return false, nil
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}
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}
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verified := p.VerifyGroupMessage(dgm.GetOnion(), group.GroupID, dgm.GetText(), dgm.GetTimestamp(), ciphertext, signature)
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return true, group.AddMessage(dgm, signature, verified)
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}
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}
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return false, nil
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}
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func getRandomness(arr *[]byte) {
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if _, err := io.ReadFull(rand.Reader, (*arr)[:]); err != nil {
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utils.CheckError(err)
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}
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}
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// EncryptMessageToGroup when given a message and a group, encrypts and signs the message under the group and
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// profile
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func (p *Profile) EncryptMessageToGroup(message string, groupID string) ([]byte, []byte, error) {
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group := p.GetGroupByGroupID(groupID)
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if group != nil {
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timestamp := time.Now().Unix()
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var prevSig []byte
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if len(group.Timeline.Messages) > 0 {
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prevSig = group.Timeline.Messages[len(group.Timeline.Messages)-1].Signature
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} else {
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prevSig = group.SignedGroupID
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}
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lenPadding := 1024 - len(message)
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padding := make([]byte, lenPadding)
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getRandomness(&padding)
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dm := &protocol.DecryptedGroupMessage{
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Onion: proto.String(p.Onion),
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Text: proto.String(message),
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SignedGroupId: group.SignedGroupID[:],
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Timestamp: proto.Int32(int32(timestamp)),
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PreviousMessageSig: prevSig,
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Padding: padding[:],
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}
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ciphertext := group.EncryptMessage(dm)
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signature := p.SignMessage(groupID + group.GroupServer + string(ciphertext))
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return ciphertext, signature, nil
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}
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return nil, nil, errors.New("group does not exist")
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}
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