86 lines
2.8 KiB
Go
86 lines
2.8 KiB
Go
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// Copyright (c) 2021 Tulir Asokan
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//
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this
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// file, You can obtain one at http://mozilla.org/MPL/2.0/.
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// Package appstate implements encoding and decoding WhatsApp's app state patches.
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package appstate
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import (
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"encoding/base64"
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"sync"
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"go.mau.fi/whatsmeow/store"
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"go.mau.fi/whatsmeow/util/hkdfutil"
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waLog "go.mau.fi/whatsmeow/util/log"
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)
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// WAPatchName represents a type of app state patch.
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type WAPatchName string
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const (
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// WAPatchCriticalBlock contains the user's settings like push name and locale.
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WAPatchCriticalBlock WAPatchName = "critical_block"
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// WAPatchCriticalUnblockLow contains the user's contact list.
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WAPatchCriticalUnblockLow WAPatchName = "critical_unblock_low"
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// WAPatchRegularLow contains some local chat settings like pin, archive status, and the setting of whether to unarchive chats when messages come in.
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WAPatchRegularLow WAPatchName = "regular_low"
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// WAPatchRegularHigh contains more local chat settings like mute status and starred messages.
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WAPatchRegularHigh WAPatchName = "regular_high"
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// WAPatchRegular contains protocol info about app state patches like key expiration.
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WAPatchRegular WAPatchName = "regular"
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)
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// AllPatchNames contains all currently known patch state names.
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var AllPatchNames = [...]WAPatchName{WAPatchCriticalBlock, WAPatchCriticalUnblockLow, WAPatchRegularHigh, WAPatchRegular, WAPatchRegularLow}
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type Processor struct {
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keyCache map[string]ExpandedAppStateKeys
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keyCacheLock sync.Mutex
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Store *store.Device
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Log waLog.Logger
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}
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func NewProcessor(store *store.Device, log waLog.Logger) *Processor {
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return &Processor{
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keyCache: make(map[string]ExpandedAppStateKeys),
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Store: store,
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Log: log,
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}
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}
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type ExpandedAppStateKeys struct {
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Index []byte
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ValueEncryption []byte
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ValueMAC []byte
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SnapshotMAC []byte
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PatchMAC []byte
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}
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func expandAppStateKeys(keyData []byte) (keys ExpandedAppStateKeys) {
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appStateKeyExpanded := hkdfutil.SHA256(keyData, nil, []byte("WhatsApp Mutation Keys"), 160)
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return ExpandedAppStateKeys{appStateKeyExpanded[0:32], appStateKeyExpanded[32:64], appStateKeyExpanded[64:96], appStateKeyExpanded[96:128], appStateKeyExpanded[128:160]}
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}
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func (proc *Processor) getAppStateKey(keyID []byte) (keys ExpandedAppStateKeys, err error) {
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keyCacheID := base64.RawStdEncoding.EncodeToString(keyID)
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var ok bool
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proc.keyCacheLock.Lock()
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defer proc.keyCacheLock.Unlock()
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keys, ok = proc.keyCache[keyCacheID]
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if !ok {
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var keyData *store.AppStateSyncKey
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keyData, err = proc.Store.AppStateKeys.GetAppStateSyncKey(keyID)
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if keyData != nil {
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keys = expandAppStateKeys(keyData.Data)
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proc.keyCache[keyCacheID] = keys
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} else if err == nil {
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err = ErrKeyNotFound
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}
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}
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return
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}
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