diff --git a/src/Importers/ImportEPUB.cpp b/src/Importers/ImportEPUB.cpp index 501f49f8e5..2f5c25f405 100644 --- a/src/Importers/ImportEPUB.cpp +++ b/src/Importers/ImportEPUB.cpp @@ -425,12 +425,41 @@ void ImportEPUB::ExtractContainer() // If there is no file name then we can't do anything with it. if (!qfile_name.isEmpty()) { - // for security reasons we need the file path to always be inside the - // target folder and not outside, so we will remove all relative upward - // paths segments ".." from the file path before prepending the target - // folder to create the final target path - qfile_name = qfile_name.replace("../",""); - cp437_file_name = cp437_file_name.replace("../",""); + // for security reasons against maliciously crafted zip archives + // we need the file path to always be inside the target folder + // and not outside, so we will remove all illegal backslashes + // and all relative upward paths segments "/../" from the zip's local + // file name/path before prepending the target folder to create + // the final path + + QString original_path = qfile_name; + bool evil_or_corrupt_epub = false; + + if (qfile_name.contains("\\")) evil_or_corrupt_epub = true; + qfile_name = "/" + qfile_name.replace("\\",""); + + if (qfile_name.contains("/../")) evil_or_corrupt_epub = true; + qfile_name = qfile_name.replace("/../","/"); + + while(qfile_name.startsWith("/")) { + qfile_name = qfile_name.remove(0,1); + } + + if (cp437_file_name.contains("\\")) evil_or_corrupt_epub = true; + cp437_file_name = "/" + cp437_file_name.replace("\\",""); + + if (cp437_file_name.contains("/../")) evil_or_corrupt_epub = true; + cp437_file_name = cp437_file_name.replace("/../","/"); + + while(cp437_file_name.startsWith("/")) { + cp437_file_name = cp437_file_name.remove(0,1); + } + + if (evil_or_corrupt_epub) { + unzCloseCurrentFile(zfile); + unzClose(zfile); + throw (EPUBLoadParseError(QString(QObject::tr("Possible evil or corrupt epub file name: %1")).arg(original_path).toStdString())); + } // We use the dir object to create the path in the temporary directory. // Unfortunately, we need a dir ojbect to do this as it's not a static function.