1 files changed, 213 insertions, 0 deletions
diff --git a/vendor/go.mau.fi/whatsmeow/download.go b/vendor/go.mau.fi/whatsmeow/download.go
new file mode 100644
index 00000000..502c4ee8
--- /dev/null
+++ b/vendor/go.mau.fi/whatsmeow/download.go
@@ -0,0 +1,213 @@
+// 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 whatsmeow
+
+import (
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/base64"
+	"fmt"
+	"io"
+	"net/http"
+
+	"google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/reflect/protoreflect"
+
+	waProto "go.mau.fi/whatsmeow/binary/proto"
+	"go.mau.fi/whatsmeow/util/cbcutil"
+	"go.mau.fi/whatsmeow/util/hkdfutil"
+)
+
+// MediaType represents a type of uploaded file on WhatsApp.
+// The value is the key which is used as a part of generating the encryption keys.
+type MediaType string
+
+// The known media types
+const (
+	MediaImage    MediaType = "WhatsApp Image Keys"
+	MediaVideo    MediaType = "WhatsApp Video Keys"
+	MediaAudio    MediaType = "WhatsApp Audio Keys"
+	MediaDocument MediaType = "WhatsApp Document Keys"
+	MediaHistory  MediaType = "WhatsApp History Keys"
+	MediaAppState MediaType = "WhatsApp App State Keys"
+)
+
+// DownloadableMessage represents a protobuf message that contains attachment info.
+type DownloadableMessage interface {
+	proto.Message
+	GetDirectPath() string
+	GetMediaKey() []byte
+	GetFileSha256() []byte
+	GetFileEncSha256() []byte
+}
+
+// All the message types that are intended to be downloadable
+var (
+	_ DownloadableMessage = (*waProto.ImageMessage)(nil)
+	_ DownloadableMessage = (*waProto.AudioMessage)(nil)
+	_ DownloadableMessage = (*waProto.VideoMessage)(nil)
+	_ DownloadableMessage = (*waProto.DocumentMessage)(nil)
+	_ DownloadableMessage = (*waProto.StickerMessage)(nil)
+	_ DownloadableMessage = (*waProto.HistorySyncNotification)(nil)
+	_ DownloadableMessage = (*waProto.ExternalBlobReference)(nil)
+)
+
+type downloadableMessageWithLength interface {
+	DownloadableMessage
+	GetFileLength() uint64
+}
+
+type downloadableMessageWithSizeBytes interface {
+	DownloadableMessage
+	GetFileSizeBytes() uint64
+}
+
+type downloadableMessageWithURL interface {
+	DownloadableMessage
+	GetUrl() string
+}
+
+var classToMediaType = map[protoreflect.Name]MediaType{
+	"ImageMessage":    MediaImage,
+	"AudioMessage":    MediaAudio,
+	"VideoMessage":    MediaVideo,
+	"DocumentMessage": MediaDocument,
+	"StickerMessage":  MediaImage,
+
+	"HistorySyncNotification": MediaHistory,
+	"ExternalBlobReference":   MediaAppState,
+}
+
+var mediaTypeToMMSType = map[MediaType]string{
+	MediaImage:    "image",
+	MediaAudio:    "audio",
+	MediaVideo:    "video",
+	MediaDocument: "document",
+	MediaHistory:  "md-msg-hist",
+	MediaAppState: "md-app-state",
+}
+
+// DownloadAny loops through the downloadable parts of the given message and downloads the first non-nil item.
+func (cli *Client) DownloadAny(msg *waProto.Message) (data []byte, err error) {
+	downloadables := []DownloadableMessage{msg.GetImageMessage(), msg.GetAudioMessage(), msg.GetVideoMessage(), msg.GetDocumentMessage(), msg.GetStickerMessage()}
+	for _, downloadable := range downloadables {
+		if downloadable != nil {
+			return cli.Download(downloadable)
+		}
+	}
+	return nil, ErrNothingDownloadableFound
+}
+
+func getSize(msg DownloadableMessage) int {
+	switch sized := msg.(type) {
+	case downloadableMessageWithLength:
+		return int(sized.GetFileLength())
+	case downloadableMessageWithSizeBytes:
+		return int(sized.GetFileSizeBytes())
+	default:
+		return -1
+	}
+}
+
+// Download downloads the attachment from the given protobuf message.
+func (cli *Client) Download(msg DownloadableMessage) (data []byte, err error) {
+	mediaType, ok := classToMediaType[msg.ProtoReflect().Descriptor().Name()]
+	if !ok {
+		return nil, fmt.Errorf("%w '%s'", ErrUnknownMediaType, string(msg.ProtoReflect().Descriptor().Name()))
+	}
+	urlable, ok := msg.(downloadableMessageWithURL)
+	if ok && len(urlable.GetUrl()) > 0 {
+		return downloadAndDecrypt(urlable.GetUrl(), msg.GetMediaKey(), mediaType, getSize(msg), msg.GetFileEncSha256(), msg.GetFileSha256())
+	} else if len(msg.GetDirectPath()) > 0 {
+		return cli.downloadMediaWithPath(msg.GetDirectPath(), msg.GetFileEncSha256(), msg.GetFileSha256(), msg.GetMediaKey(), getSize(msg), mediaType, mediaTypeToMMSType[mediaType])
+	} else {
+		return nil, ErrNoURLPresent
+	}
+}
+
+func (cli *Client) downloadMediaWithPath(directPath string, encFileHash, fileHash, mediaKey []byte, fileLength int, mediaType MediaType, mmsType string) (data []byte, err error) {
+	err = cli.refreshMediaConn(false)
+	if err != nil {
+		return nil, fmt.Errorf("failed to refresh media connections: %w", err)
+	}
+	for i, host := range cli.mediaConn.Hosts {
+		mediaURL := fmt.Sprintf("https://%s%s&hash=%s&mms-type=%s&__wa-mms=", host.Hostname, directPath, base64.URLEncoding.EncodeToString(encFileHash), mmsType)
+		data, err = downloadAndDecrypt(mediaURL, mediaKey, mediaType, fileLength, encFileHash, fileHash)
+		// TODO there are probably some errors that shouldn't retry
+		if err != nil {
+			if i >= len(cli.mediaConn.Hosts)-1 {
+				return nil, fmt.Errorf("failed to download media from last host: %w", err)
+			}
+			cli.Log.Warnf("Failed to download media: %s, trying with next host...", err)
+		}
+	}
+	return
+}
+
+func downloadAndDecrypt(url string, mediaKey []byte, appInfo MediaType, fileLength int, fileEncSha256, fileSha256 []byte) (data []byte, err error) {
+	iv, cipherKey, macKey, _ := getMediaKeys(mediaKey, appInfo)
+	var ciphertext, mac []byte
+	if ciphertext, mac, err = downloadEncryptedMedia(url, fileEncSha256); err != nil {
+
+	} else if err = validateMedia(iv, ciphertext, macKey, mac); err != nil {
+
+	} else if data, err = cbcutil.Decrypt(cipherKey, iv, ciphertext); err != nil {
+		err = fmt.Errorf("failed to decrypt file: %w", err)
+	} else if fileLength >= 0 && len(data) != fileLength {
+		err = fmt.Errorf("%w: expected %d, got %d", ErrFileLengthMismatch, fileLength, len(data))
+	} else if len(fileSha256) == 32 && sha256.Sum256(data) != *(*[32]byte)(fileSha256) {
+		err = ErrInvalidMediaSHA256
+	}
+	return
+}
+
+func getMediaKeys(mediaKey []byte, appInfo MediaType) (iv, cipherKey, macKey, refKey []byte) {
+	mediaKeyExpanded := hkdfutil.SHA256(mediaKey, nil, []byte(appInfo), 112)
+	return mediaKeyExpanded[:16], mediaKeyExpanded[16:48], mediaKeyExpanded[48:80], mediaKeyExpanded[80:]
+}
+
+func downloadEncryptedMedia(url string, checksum []byte) (file, mac []byte, err error) {
+	var resp *http.Response
+	resp, err = http.Get(url)
+	if err != nil {
+		return
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		if resp.StatusCode == http.StatusNotFound {
+			err = ErrMediaDownloadFailedWith404
+		} else if resp.StatusCode == http.StatusGone {
+			err = ErrMediaDownloadFailedWith410
+		} else {
+			err = fmt.Errorf("download failed with status code %d", resp.StatusCode)
+		}
+		return
+	}
+	var data []byte
+	data, err = io.ReadAll(resp.Body)
+	if err != nil {
+		return
+	} else if len(data) <= 10 {
+		err = ErrTooShortFile
+		return
+	}
+	file, mac = data[:len(data)-10], data[len(data)-10:]
+	if len(checksum) == 32 && sha256.Sum256(data) != *(*[32]byte)(checksum) {
+		err = ErrInvalidMediaEncSHA256
+	}
+	return
+}
+
+func validateMedia(iv, file, macKey, mac []byte) error {
+	h := hmac.New(sha256.New, macKey)
+	h.Write(iv)
+	h.Write(file)
+	if !hmac.Equal(h.Sum(nil)[:10], mac) {
+		return ErrInvalidMediaHMAC
+	}
+	return nil
+}