mirror of
https://github.com/cwinfo/matterbridge.git
synced 2024-12-01 12:21:35 +00:00
311 lines
11 KiB
Go
311 lines
11 KiB
Go
// Copyright (c) 2021 Tulir Asokan
|
|
//
|
|
// This Source Code Form is subject to the terms of the Mozilla Public
|
|
// License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
|
|
|
|
package appstate
|
|
|
|
import (
|
|
"bytes"
|
|
"crypto/sha256"
|
|
"encoding/json"
|
|
"fmt"
|
|
|
|
"google.golang.org/protobuf/proto"
|
|
|
|
waBinary "go.mau.fi/whatsmeow/binary"
|
|
waProto "go.mau.fi/whatsmeow/binary/proto"
|
|
"go.mau.fi/whatsmeow/store"
|
|
"go.mau.fi/whatsmeow/util/cbcutil"
|
|
)
|
|
|
|
// PatchList represents a decoded response to getting app state patches from the WhatsApp servers.
|
|
type PatchList struct {
|
|
Name WAPatchName
|
|
HasMorePatches bool
|
|
Patches []*waProto.SyncdPatch
|
|
Snapshot *waProto.SyncdSnapshot
|
|
}
|
|
|
|
// DownloadExternalFunc is a function that can download a blob of external app state patches.
|
|
type DownloadExternalFunc func(*waProto.ExternalBlobReference) ([]byte, error)
|
|
|
|
func parseSnapshotInternal(collection *waBinary.Node, downloadExternal DownloadExternalFunc) (*waProto.SyncdSnapshot, error) {
|
|
snapshotNode := collection.GetChildByTag("snapshot")
|
|
rawSnapshot, ok := snapshotNode.Content.([]byte)
|
|
if snapshotNode.Tag != "snapshot" || !ok {
|
|
return nil, nil
|
|
}
|
|
var snapshot waProto.ExternalBlobReference
|
|
err := proto.Unmarshal(rawSnapshot, &snapshot)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("failed to unmarshal snapshot: %w", err)
|
|
}
|
|
var rawData []byte
|
|
rawData, err = downloadExternal(&snapshot)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("failed to download external mutations: %w", err)
|
|
}
|
|
var downloaded waProto.SyncdSnapshot
|
|
err = proto.Unmarshal(rawData, &downloaded)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("failed to unmarshal mutation list: %w", err)
|
|
}
|
|
return &downloaded, nil
|
|
}
|
|
|
|
func parsePatchListInternal(collection *waBinary.Node, downloadExternal DownloadExternalFunc) ([]*waProto.SyncdPatch, error) {
|
|
patchesNode := collection.GetChildByTag("patches")
|
|
patchNodes := patchesNode.GetChildren()
|
|
patches := make([]*waProto.SyncdPatch, 0, len(patchNodes))
|
|
for i, patchNode := range patchNodes {
|
|
rawPatch, ok := patchNode.Content.([]byte)
|
|
if patchNode.Tag != "patch" || !ok {
|
|
continue
|
|
}
|
|
var patch waProto.SyncdPatch
|
|
err := proto.Unmarshal(rawPatch, &patch)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("failed to unmarshal patch #%d: %w", i+1, err)
|
|
}
|
|
if patch.GetExternalMutations() != nil && downloadExternal != nil {
|
|
var rawData []byte
|
|
rawData, err = downloadExternal(patch.GetExternalMutations())
|
|
if err != nil {
|
|
return nil, fmt.Errorf("failed to download external mutations: %w", err)
|
|
}
|
|
var downloaded waProto.SyncdMutations
|
|
err = proto.Unmarshal(rawData, &downloaded)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("failed to unmarshal mutation list: %w", err)
|
|
} else if len(downloaded.GetMutations()) == 0 {
|
|
return nil, fmt.Errorf("didn't get any mutations from download")
|
|
}
|
|
patch.Mutations = downloaded.Mutations
|
|
}
|
|
patches = append(patches, &patch)
|
|
}
|
|
return patches, nil
|
|
}
|
|
|
|
// ParsePatchList will decode an XML node containing app state patches, including downloading any external blobs.
|
|
func ParsePatchList(node *waBinary.Node, downloadExternal DownloadExternalFunc) (*PatchList, error) {
|
|
collection := node.GetChildByTag("sync", "collection")
|
|
ag := collection.AttrGetter()
|
|
snapshot, err := parseSnapshotInternal(&collection, downloadExternal)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
patches, err := parsePatchListInternal(&collection, downloadExternal)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
list := &PatchList{
|
|
Name: WAPatchName(ag.String("name")),
|
|
HasMorePatches: ag.OptionalBool("has_more_patches"),
|
|
Patches: patches,
|
|
Snapshot: snapshot,
|
|
}
|
|
return list, ag.Error()
|
|
}
|
|
|
|
type patchOutput struct {
|
|
RemovedMACs [][]byte
|
|
AddedMACs []store.AppStateMutationMAC
|
|
Mutations []Mutation
|
|
}
|
|
|
|
func (proc *Processor) decodeMutations(mutations []*waProto.SyncdMutation, out *patchOutput, validateMACs bool) error {
|
|
for i, mutation := range mutations {
|
|
keyID := mutation.GetRecord().GetKeyId().GetId()
|
|
keys, err := proc.getAppStateKey(keyID)
|
|
if err != nil {
|
|
return fmt.Errorf("failed to get key %X to decode mutation: %w", keyID, err)
|
|
}
|
|
content := mutation.GetRecord().GetValue().GetBlob()
|
|
content, valueMAC := content[:len(content)-32], content[len(content)-32:]
|
|
if validateMACs {
|
|
expectedValueMAC := generateContentMAC(mutation.GetOperation(), content, keyID, keys.ValueMAC)
|
|
if !bytes.Equal(expectedValueMAC, valueMAC) {
|
|
return fmt.Errorf("failed to verify mutation #%d: %w", i+1, ErrMismatchingContentMAC)
|
|
}
|
|
}
|
|
iv, content := content[:16], content[16:]
|
|
plaintext, err := cbcutil.Decrypt(keys.ValueEncryption, iv, content)
|
|
if err != nil {
|
|
return fmt.Errorf("failed to decrypt mutation #%d: %w", i+1, err)
|
|
}
|
|
var syncAction waProto.SyncActionData
|
|
err = proto.Unmarshal(plaintext, &syncAction)
|
|
if err != nil {
|
|
return fmt.Errorf("failed to unmarshal mutation #%d: %w", i+1, err)
|
|
}
|
|
indexMAC := mutation.GetRecord().GetIndex().GetBlob()
|
|
if validateMACs {
|
|
expectedIndexMAC := concatAndHMAC(sha256.New, keys.Index, syncAction.Index)
|
|
if !bytes.Equal(expectedIndexMAC, indexMAC) {
|
|
return fmt.Errorf("failed to verify mutation #%d: %w", i+1, ErrMismatchingIndexMAC)
|
|
}
|
|
}
|
|
var index []string
|
|
err = json.Unmarshal(syncAction.GetIndex(), &index)
|
|
if err != nil {
|
|
return fmt.Errorf("failed to unmarshal index of mutation #%d: %w", i+1, err)
|
|
}
|
|
if mutation.GetOperation() == waProto.SyncdMutation_REMOVE {
|
|
out.RemovedMACs = append(out.RemovedMACs, indexMAC)
|
|
} else if mutation.GetOperation() == waProto.SyncdMutation_SET {
|
|
out.AddedMACs = append(out.AddedMACs, store.AppStateMutationMAC{
|
|
IndexMAC: indexMAC,
|
|
ValueMAC: valueMAC,
|
|
})
|
|
}
|
|
out.Mutations = append(out.Mutations, Mutation{
|
|
Operation: mutation.GetOperation(),
|
|
Action: syncAction.GetValue(),
|
|
Index: index,
|
|
IndexMAC: indexMAC,
|
|
ValueMAC: valueMAC,
|
|
})
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (proc *Processor) storeMACs(name WAPatchName, currentState HashState, out *patchOutput) {
|
|
err := proc.Store.AppState.PutAppStateVersion(string(name), currentState.Version, currentState.Hash)
|
|
if err != nil {
|
|
proc.Log.Errorf("Failed to update app state version in the database: %v", err)
|
|
}
|
|
err = proc.Store.AppState.DeleteAppStateMutationMACs(string(name), out.RemovedMACs)
|
|
if err != nil {
|
|
proc.Log.Errorf("Failed to remove deleted mutation MACs from the database: %v", err)
|
|
}
|
|
err = proc.Store.AppState.PutAppStateMutationMACs(string(name), currentState.Version, out.AddedMACs)
|
|
if err != nil {
|
|
proc.Log.Errorf("Failed to insert added mutation MACs to the database: %v", err)
|
|
}
|
|
}
|
|
|
|
func (proc *Processor) validateSnapshotMAC(name WAPatchName, currentState HashState, keyID, expectedSnapshotMAC []byte) (keys ExpandedAppStateKeys, err error) {
|
|
keys, err = proc.getAppStateKey(keyID)
|
|
if err != nil {
|
|
err = fmt.Errorf("failed to get key %X to verify patch v%d MACs: %w", keyID, currentState.Version, err)
|
|
return
|
|
}
|
|
snapshotMAC := currentState.generateSnapshotMAC(name, keys.SnapshotMAC)
|
|
if !bytes.Equal(snapshotMAC, expectedSnapshotMAC) {
|
|
err = fmt.Errorf("failed to verify patch v%d: %w", currentState.Version, ErrMismatchingLTHash)
|
|
}
|
|
return
|
|
}
|
|
|
|
func (proc *Processor) decodeSnapshot(name WAPatchName, ss *waProto.SyncdSnapshot, initialState HashState, validateMACs bool, newMutationsInput []Mutation) (newMutations []Mutation, currentState HashState, err error) {
|
|
currentState = initialState
|
|
currentState.Version = ss.GetVersion().GetVersion()
|
|
|
|
encryptedMutations := make([]*waProto.SyncdMutation, len(ss.GetRecords()))
|
|
for i, record := range ss.GetRecords() {
|
|
encryptedMutations[i] = &waProto.SyncdMutation{
|
|
Operation: waProto.SyncdMutation_SET.Enum(),
|
|
Record: record,
|
|
}
|
|
}
|
|
|
|
var warn []error
|
|
warn, err = currentState.updateHash(encryptedMutations, func(indexMAC []byte, maxIndex int) ([]byte, error) {
|
|
return nil, nil
|
|
})
|
|
if len(warn) > 0 {
|
|
proc.Log.Warnf("Warnings while updating hash for %s: %+v", name, warn)
|
|
}
|
|
if err != nil {
|
|
err = fmt.Errorf("failed to update state hash: %w", err)
|
|
return
|
|
}
|
|
|
|
if validateMACs {
|
|
_, err = proc.validateSnapshotMAC(name, currentState, ss.GetKeyId().GetId(), ss.GetMac())
|
|
if err != nil {
|
|
return
|
|
}
|
|
}
|
|
|
|
var out patchOutput
|
|
out.Mutations = newMutationsInput
|
|
err = proc.decodeMutations(encryptedMutations, &out, validateMACs)
|
|
if err != nil {
|
|
err = fmt.Errorf("failed to decode snapshot of v%d: %w", currentState.Version, err)
|
|
return
|
|
}
|
|
proc.storeMACs(name, currentState, &out)
|
|
newMutations = out.Mutations
|
|
return
|
|
}
|
|
|
|
// DecodePatches will decode all the patches in a PatchList into a list of app state mutations.
|
|
func (proc *Processor) DecodePatches(list *PatchList, initialState HashState, validateMACs bool) (newMutations []Mutation, currentState HashState, err error) {
|
|
currentState = initialState
|
|
var expectedLength int
|
|
if list.Snapshot != nil {
|
|
expectedLength = len(list.Snapshot.GetRecords())
|
|
}
|
|
for _, patch := range list.Patches {
|
|
expectedLength += len(patch.GetMutations())
|
|
}
|
|
newMutations = make([]Mutation, 0, expectedLength)
|
|
|
|
if list.Snapshot != nil {
|
|
newMutations, currentState, err = proc.decodeSnapshot(list.Name, list.Snapshot, currentState, validateMACs, newMutations)
|
|
if err != nil {
|
|
return
|
|
}
|
|
}
|
|
|
|
for _, patch := range list.Patches {
|
|
version := patch.GetVersion().GetVersion()
|
|
currentState.Version = version
|
|
var warn []error
|
|
warn, err = currentState.updateHash(patch.GetMutations(), func(indexMAC []byte, maxIndex int) ([]byte, error) {
|
|
for i := maxIndex - 1; i >= 0; i-- {
|
|
if bytes.Equal(patch.Mutations[i].GetRecord().GetIndex().GetBlob(), indexMAC) {
|
|
value := patch.Mutations[i].GetRecord().GetValue().GetBlob()
|
|
return value[len(value)-32:], nil
|
|
}
|
|
}
|
|
// Previous value not found in current patch, look in the database
|
|
return proc.Store.AppState.GetAppStateMutationMAC(string(list.Name), indexMAC)
|
|
})
|
|
if len(warn) > 0 {
|
|
proc.Log.Warnf("Warnings while updating hash for %s: %+v", list.Name, warn)
|
|
}
|
|
if err != nil {
|
|
err = fmt.Errorf("failed to update state hash: %w", err)
|
|
return
|
|
}
|
|
|
|
if validateMACs {
|
|
var keys ExpandedAppStateKeys
|
|
keys, err = proc.validateSnapshotMAC(list.Name, currentState, patch.GetKeyId().GetId(), patch.GetSnapshotMac())
|
|
if err != nil {
|
|
return
|
|
}
|
|
patchMAC := generatePatchMAC(patch, list.Name, keys.PatchMAC)
|
|
if !bytes.Equal(patchMAC, patch.GetPatchMac()) {
|
|
err = fmt.Errorf("failed to verify patch v%d: %w", version, ErrMismatchingPatchMAC)
|
|
return
|
|
}
|
|
}
|
|
|
|
var out patchOutput
|
|
out.Mutations = newMutations
|
|
err = proc.decodeMutations(patch.GetMutations(), &out, validateMACs)
|
|
if err != nil {
|
|
return
|
|
}
|
|
proc.storeMACs(list.Name, currentState, &out)
|
|
newMutations = out.Mutations
|
|
}
|
|
return
|
|
}
|