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# frozen_string_literal: true
module SafeZip
class Entry
attr_reader :zip_archive, :zip_entry
attr_reader :path, :params
def initialize(zip_archive, zip_entry, params)
@zip_archive = zip_archive
@zip_entry = zip_entry
@params = params
@path = ::File.expand_path(zip_entry.name, params.extract_path)
end
def path_dir
::File.dirname(path)
end
def real_path_dir
::File.realpath(path_dir)
end
def exist?
::File.exist?(path)
end
def extract
# do not extract if file is not part of target directory or target file
return false unless matching_target_directory || matching_target_file
# do not overwrite existing file
raise SafeZip::Extract::AlreadyExistsError, "File already exists #{zip_entry.name}" if exist?
create_path_dir
if zip_entry.file?
extract_file
elsif zip_entry.directory?
extract_dir
elsif zip_entry.symlink?
extract_symlink
else
raise SafeZip::Extract::UnsupportedEntryError, "File #{zip_entry.name} cannot be extracted"
end
rescue SafeZip::Extract::Error
raise
rescue Zip::EntrySizeError => e
raise SafeZip::Extract::EntrySizeError, e.message
rescue StandardError => e
raise SafeZip::Extract::ExtractError, e.message
end
private
def extract_file
zip_archive.extract(zip_entry, path)
end
def extract_dir
FileUtils.mkdir(path)
end
def extract_symlink
source_path = read_symlink
real_source_path = expand_symlink(source_path)
# ensure that source path of symlink is within target directories
unless real_source_path.start_with?(matching_target_directory)
raise SafeZip::Extract::PermissionDeniedError, "Symlink cannot be created targeting: #{source_path}"
end
::File.symlink(source_path, path)
end
def create_path_dir
# Create all directories, but ignore permissions
FileUtils.mkdir_p(path_dir)
# disallow to make path dirs to point to another directories
unless path_dir == real_path_dir
raise SafeZip::Extract::PermissionDeniedError, "Directory of #{zip_entry.name} points to another directory"
end
end
def matching_target_directory
params.matching_target_directory(path)
end
def matching_target_file
params.matching_target_file(path)
end
def read_symlink
zip_archive.read(zip_entry)
end
def expand_symlink(source_path)
::File.realpath(source_path, path_dir)
rescue StandardError
raise SafeZip::Extract::SymlinkSourceDoesNotExistError, "Symlink source #{source_path} does not exist"
end
end
end
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