BookStack/app/Uploads/ImageService.php
Dan Brown 7224fbcc89
Added protections against path traversal in file system operations
- Files within the storage/ path could be accessed via path traversal
  references in content, accessed upon HTML export.
- This addresses this via two layers:
  - Scoped local flysystem filesystems down to the specific image &
    file folders since flysystem has built-in checking against the
    escaping of the root folder.
  - Added path normalization before enforcement of uploads/{images,file}
    prefix to prevent traversal at a path level.

Thanks to @Haxatron via huntr.dev for discovery and reporting.
Ref: https://huntr.dev/bounties/ac268a17-72b5-446f-a09a-9945ef58607a/
2021-10-08 17:47:14 +01:00

500 lines
16 KiB
PHP

<?php
namespace BookStack\Uploads;
use BookStack\Exceptions\ImageUploadException;
use ErrorException;
use Exception;
use Illuminate\Contracts\Cache\Repository as Cache;
use Illuminate\Contracts\Filesystem\Factory as FileSystem;
use Illuminate\Contracts\Filesystem\FileNotFoundException;
use Illuminate\Contracts\Filesystem\Filesystem as FileSystemInstance;
use Illuminate\Contracts\Filesystem\Filesystem as Storage;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Str;
use Intervention\Image\Exception\NotSupportedException;
use Intervention\Image\ImageManager;
use League\Flysystem\Util;
use Symfony\Component\HttpFoundation\File\UploadedFile;
class ImageService
{
protected $imageTool;
protected $cache;
protected $storageUrl;
protected $image;
protected $fileSystem;
/**
* ImageService constructor.
*/
public function __construct(Image $image, ImageManager $imageTool, FileSystem $fileSystem, Cache $cache)
{
$this->image = $image;
$this->imageTool = $imageTool;
$this->fileSystem = $fileSystem;
$this->cache = $cache;
}
/**
* Get the storage that will be used for storing images.
*/
protected function getStorage(string $imageType = ''): FileSystemInstance
{
return $this->fileSystem->disk($this->getStorageDiskName($imageType));
}
/**
* Change the originally provided path to fit any disk-specific requirements.
* This also ensures the path is kept to the expected root folders.
*/
protected function adjustPathForStorageDisk(string $path, string $imageType = ''): string
{
$path = Util::normalizePath(str_replace('uploads/images/', '', $path));
if ($this->getStorageDiskName($imageType) === 'local_secure_images') {
return $path;
}
return 'uploads/images/' . $path;
}
/**
* Get the name of the storage disk to use.
*/
protected function getStorageDiskName(string $imageType): string
{
$storageType = config('filesystems.images');
// Ensure system images (App logo) are uploaded to a public space
if ($imageType === 'system' && $storageType === 'local_secure') {
$storageType = 'local';
}
if ($storageType === 'local_secure') {
$storageType = 'local_secure_images';
}
return $storageType;
}
/**
* Saves a new image from an upload.
*
* @throws ImageUploadException
*
* @return mixed
*/
public function saveNewFromUpload(
UploadedFile $uploadedFile,
string $type,
int $uploadedTo = 0,
int $resizeWidth = null,
int $resizeHeight = null,
bool $keepRatio = true
) {
$imageName = $uploadedFile->getClientOriginalName();
$imageData = file_get_contents($uploadedFile->getRealPath());
if ($resizeWidth !== null || $resizeHeight !== null) {
$imageData = $this->resizeImage($imageData, $resizeWidth, $resizeHeight, $keepRatio);
}
return $this->saveNew($imageName, $imageData, $type, $uploadedTo);
}
/**
* Save a new image from a uri-encoded base64 string of data.
*
* @throws ImageUploadException
*/
public function saveNewFromBase64Uri(string $base64Uri, string $name, string $type, int $uploadedTo = 0): Image
{
$splitData = explode(';base64,', $base64Uri);
if (count($splitData) < 2) {
throw new ImageUploadException('Invalid base64 image data provided');
}
$data = base64_decode($splitData[1]);
return $this->saveNew($name, $data, $type, $uploadedTo);
}
/**
* Save a new image into storage.
*
* @throws ImageUploadException
*/
public function saveNew(string $imageName, string $imageData, string $type, int $uploadedTo = 0): Image
{
$storage = $this->getStorage($type);
$secureUploads = setting('app-secure-images');
$fileName = $this->cleanImageFileName($imageName);
$imagePath = '/uploads/images/' . $type . '/' . date('Y-m') . '/';
while ($storage->exists($this->adjustPathForStorageDisk($imagePath . $fileName, $type))) {
$fileName = Str::random(3) . $fileName;
}
$fullPath = $imagePath . $fileName;
if ($secureUploads) {
$fullPath = $imagePath . Str::random(16) . '-' . $fileName;
}
try {
$this->saveImageDataInPublicSpace($storage, $this->adjustPathForStorageDisk($fullPath, $type), $imageData);
} catch (Exception $e) {
\Log::error('Error when attempting image upload:' . $e->getMessage());
throw new ImageUploadException(trans('errors.path_not_writable', ['filePath' => $fullPath]));
}
$imageDetails = [
'name' => $imageName,
'path' => $fullPath,
'url' => $this->getPublicUrl($fullPath),
'type' => $type,
'uploaded_to' => $uploadedTo,
];
if (user()->id !== 0) {
$userId = user()->id;
$imageDetails['created_by'] = $userId;
$imageDetails['updated_by'] = $userId;
}
$image = $this->image->newInstance();
$image->forceFill($imageDetails)->save();
return $image;
}
/**
* Save image data for the given path in the public space, if possible,
* for the provided storage mechanism.
*/
protected function saveImageDataInPublicSpace(Storage $storage, string $path, string $data)
{
$storage->put($path, $data);
// Set visibility when a non-AWS-s3, s3-like storage option is in use.
// Done since this call can break s3-like services but desired for other image stores.
// Attempting to set ACL during above put request requires different permissions
// hence would technically be a breaking change for actual s3 usage.
$usingS3 = strtolower(config('filesystems.images')) === 's3';
$usingS3Like = $usingS3 && !is_null(config('filesystems.disks.s3.endpoint'));
if (!$usingS3Like) {
$storage->setVisibility($path, 'public');
}
}
/**
* Clean up an image file name to be both URL and storage safe.
*/
protected function cleanImageFileName(string $name): string
{
$name = str_replace(' ', '-', $name);
$nameParts = explode('.', $name);
$extension = array_pop($nameParts);
$name = implode('-', $nameParts);
$name = Str::slug($name);
if (strlen($name) === 0) {
$name = Str::random(10);
}
return $name . '.' . $extension;
}
/**
* Checks if the image is a gif. Returns true if it is, else false.
*/
protected function isGif(Image $image): bool
{
return strtolower(pathinfo($image->path, PATHINFO_EXTENSION)) === 'gif';
}
/**
* Get the thumbnail for an image.
* If $keepRatio is true only the width will be used.
* Checks the cache then storage to avoid creating / accessing the filesystem on every check.
*
* @param Image $image
* @param int $width
* @param int $height
* @param bool $keepRatio
*
* @throws Exception
* @throws ImageUploadException
*
* @return string
*/
public function getThumbnail(Image $image, $width = 220, $height = 220, $keepRatio = false)
{
if ($keepRatio && $this->isGif($image)) {
return $this->getPublicUrl($image->path);
}
$thumbDirName = '/' . ($keepRatio ? 'scaled-' : 'thumbs-') . $width . '-' . $height . '/';
$imagePath = $image->path;
$thumbFilePath = dirname($imagePath) . $thumbDirName . basename($imagePath);
if ($this->cache->has('images-' . $image->id . '-' . $thumbFilePath) && $this->cache->get('images-' . $thumbFilePath)) {
return $this->getPublicUrl($thumbFilePath);
}
$storage = $this->getStorage($image->type);
if ($storage->exists($this->adjustPathForStorageDisk($thumbFilePath, $image->type))) {
return $this->getPublicUrl($thumbFilePath);
}
$thumbData = $this->resizeImage($storage->get($this->adjustPathForStorageDisk($imagePath, $image->type)), $width, $height, $keepRatio);
$this->saveImageDataInPublicSpace($storage, $this->adjustPathForStorageDisk($thumbFilePath, $image->type), $thumbData);
$this->cache->put('images-' . $image->id . '-' . $thumbFilePath, $thumbFilePath, 60 * 60 * 72);
return $this->getPublicUrl($thumbFilePath);
}
/**
* Resize image data.
*
* @param string $imageData
* @param int $width
* @param int $height
* @param bool $keepRatio
*
* @throws ImageUploadException
*
* @return string
*/
protected function resizeImage(string $imageData, $width = 220, $height = null, bool $keepRatio = true)
{
try {
$thumb = $this->imageTool->make($imageData);
} catch (Exception $e) {
if ($e instanceof ErrorException || $e instanceof NotSupportedException) {
throw new ImageUploadException(trans('errors.cannot_create_thumbs'));
}
throw $e;
}
if ($keepRatio) {
$thumb->resize($width, $height, function ($constraint) {
$constraint->aspectRatio();
$constraint->upsize();
});
} else {
$thumb->fit($width, $height);
}
$thumbData = (string) $thumb->encode();
// Use original image data if we're keeping the ratio
// and the resizing does not save any space.
if ($keepRatio && strlen($thumbData) > strlen($imageData)) {
return $imageData;
}
return $thumbData;
}
/**
* Get the raw data content from an image.
*
* @throws FileNotFoundException
*/
public function getImageData(Image $image): string
{
$storage = $this->getStorage();
return $storage->get($this->adjustPathForStorageDisk($image->path, $image->type));
}
/**
* Destroy an image along with its revisions, thumbnails and remaining folders.
*
* @throws Exception
*/
public function destroy(Image $image)
{
$this->destroyImagesFromPath($image->path, $image->type);
$image->delete();
}
/**
* Destroys an image at the given path.
* Searches for image thumbnails in addition to main provided path.
*/
protected function destroyImagesFromPath(string $path, string $imageType): bool
{
$path = $this->adjustPathForStorageDisk($path, $imageType);
$storage = $this->getStorage($imageType);
$imageFolder = dirname($path);
$imageFileName = basename($path);
$allImages = collect($storage->allFiles($imageFolder));
// Delete image files
$imagesToDelete = $allImages->filter(function ($imagePath) use ($imageFileName) {
return basename($imagePath) === $imageFileName;
});
$storage->delete($imagesToDelete->all());
// Cleanup of empty folders
$foldersInvolved = array_merge([$imageFolder], $storage->directories($imageFolder));
foreach ($foldersInvolved as $directory) {
if ($this->isFolderEmpty($storage, $directory)) {
$storage->deleteDirectory($directory);
}
}
return true;
}
/**
* Check whether a folder is empty.
*/
protected function isFolderEmpty(FileSystemInstance $storage, string $path): bool
{
$files = $storage->files($path);
$folders = $storage->directories($path);
return count($files) === 0 && count($folders) === 0;
}
/**
* Delete gallery and drawings that are not within HTML content of pages or page revisions.
* Checks based off of only the image name.
* Could be much improved to be more specific but kept it generic for now to be safe.
*
* Returns the path of the images that would be/have been deleted.
*/
public function deleteUnusedImages(bool $checkRevisions = true, bool $dryRun = true)
{
$types = ['gallery', 'drawio'];
$deletedPaths = [];
$this->image->newQuery()->whereIn('type', $types)
->chunk(1000, function ($images) use ($checkRevisions, &$deletedPaths, $dryRun) {
foreach ($images as $image) {
$searchQuery = '%' . basename($image->path) . '%';
$inPage = DB::table('pages')
->where('html', 'like', $searchQuery)->count() > 0;
$inRevision = false;
if ($checkRevisions) {
$inRevision = DB::table('page_revisions')
->where('html', 'like', $searchQuery)->count() > 0;
}
if (!$inPage && !$inRevision) {
$deletedPaths[] = $image->path;
if (!$dryRun) {
$this->destroy($image);
}
}
}
});
return $deletedPaths;
}
/**
* Convert an image URI to a Base64 encoded string.
* Attempts to convert the URL to a system storage url then
* fetch the data from the disk or storage location.
* Returns null if the image data cannot be fetched from storage.
*
* @throws FileNotFoundException
*/
public function imageUriToBase64(string $uri): ?string
{
$storagePath = $this->imageUrlToStoragePath($uri);
if (empty($uri) || is_null($storagePath)) {
return null;
}
$storagePath = $this->adjustPathForStorageDisk($storagePath);
$storage = $this->getStorage();
$imageData = null;
if ($storage->exists($storagePath)) {
$imageData = $storage->get($storagePath);
}
if (is_null($imageData)) {
return null;
}
$extension = pathinfo($uri, PATHINFO_EXTENSION);
if ($extension === 'svg') {
$extension = 'svg+xml';
}
return 'data:image/' . $extension . ';base64,' . base64_encode($imageData);
}
/**
* Get a storage path for the given image URL.
* Ensures the path will start with "uploads/images".
* Returns null if the url cannot be resolved to a local URL.
*/
private function imageUrlToStoragePath(string $url): ?string
{
$url = ltrim(trim($url), '/');
// Handle potential relative paths
$isRelative = strpos($url, 'http') !== 0;
if ($isRelative) {
if (strpos(strtolower($url), 'uploads/images') === 0) {
return trim($url, '/');
}
return null;
}
// Handle local images based on paths on the same domain
$potentialHostPaths = [
url('uploads/images/'),
$this->getPublicUrl('/uploads/images/'),
];
foreach ($potentialHostPaths as $potentialBasePath) {
$potentialBasePath = strtolower($potentialBasePath);
if (strpos(strtolower($url), $potentialBasePath) === 0) {
return 'uploads/images/' . trim(substr($url, strlen($potentialBasePath)), '/');
}
}
return null;
}
/**
* Gets a public facing url for an image by checking relevant environment variables.
* If s3-style store is in use it will default to guessing a public bucket URL.
*/
private function getPublicUrl(string $filePath): string
{
if ($this->storageUrl === null) {
$storageUrl = config('filesystems.url');
// Get the standard public s3 url if s3 is set as storage type
// Uses the nice, short URL if bucket name has no periods in otherwise the longer
// region-based url will be used to prevent http issues.
if ($storageUrl == false && config('filesystems.images') === 's3') {
$storageDetails = config('filesystems.disks.s3');
if (strpos($storageDetails['bucket'], '.') === false) {
$storageUrl = 'https://' . $storageDetails['bucket'] . '.s3.amazonaws.com';
} else {
$storageUrl = 'https://s3-' . $storageDetails['region'] . '.amazonaws.com/' . $storageDetails['bucket'];
}
}
$this->storageUrl = $storageUrl;
}
$basePath = ($this->storageUrl == false) ? url('/') : $this->storageUrl;
return rtrim($basePath, '/') . $filePath;
}
}