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Diffstat (limited to 'paramiko/sftp_server.py')
| -rw-r--r-- | paramiko/sftp_server.py | 420 |
1 files changed, 420 insertions, 0 deletions
diff --git a/paramiko/sftp_server.py b/paramiko/sftp_server.py new file mode 100644 index 0000000..5905843 --- /dev/null +++ b/paramiko/sftp_server.py @@ -0,0 +1,420 @@ +# Copyright (C) 2003-2005 Robey Pointer <robey@lag.net> +# +# This file is part of paramiko. +# +# Paramiko is free software; you can redistribute it and/or modify it under the +# terms of the GNU Lesser General Public License as published by the Free +# Software Foundation; either version 2.1 of the License, or (at your option) +# any later version. +# +# Paramiko is distrubuted in the hope that it will be useful, but WITHOUT ANY +# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR +# A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more +# details. +# +# You should have received a copy of the GNU Lesser General Public License +# along with Paramiko; if not, write to the Free Software Foundation, Inc., +# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. + +""" +Server-mode SFTP support. +""" + +import os +import errno + +from Crypto.Hash import MD5, SHA +from paramiko.common import * +from paramiko.server import SubsystemHandler +from paramiko.sftp import * +from paramiko.sftp_si import * +from paramiko.sftp_attr import * + + +# known hash algorithms for the "check-file" extension +_hash_class = { + 'sha1': SHA, + 'md5': MD5, +} + + +class SFTPServer (BaseSFTP, SubsystemHandler): + """ + Server-side SFTP subsystem support. Since this is a L{SubsystemHandler}, + it can be (and is meant to be) set as the handler for C{"sftp"} requests. + Use L{Transport.set_subsystem_handler} to activate this class. + """ + + def __init__(self, channel, name, server, sftp_si=SFTPServerInterface, *largs, **kwargs): + """ + The constructor for SFTPServer is meant to be called from within the + L{Transport} as a subsystem handler. C{server} and any additional + parameters or keyword parameters are passed from the original call to + L{Transport.set_subsystem_handler}. + + @param channel: channel passed from the L{Transport}. + @type channel: L{Channel} + @param name: name of the requested subsystem. + @type name: str + @param server: the server object associated with this channel and + subsystem + @type server: L{ServerInterface} + @param sftp_si: a subclass of L{SFTPServerInterface} to use for handling + individual requests. + @type sftp_si: class + """ + BaseSFTP.__init__(self) + SubsystemHandler.__init__(self, channel, name, server) + transport = channel.get_transport() + self.logger = util.get_logger(transport.get_log_channel() + '.' + + channel.get_name() + '.sftp') + self.ultra_debug = transport.get_hexdump() + self.next_handle = 1 + # map of handle-string to SFTPHandle for files & folders: + self.file_table = { } + self.folder_table = { } + self.server = sftp_si(server, *largs, **kwargs) + + def start_subsystem(self, name, transport, channel): + self.sock = channel + self._log(DEBUG, 'Started sftp server on channel %s' % repr(channel)) + self._send_server_version() + self.server.session_started() + while True: + try: + t, data = self._read_packet() + except EOFError: + self._log(DEBUG, 'EOF -- end of session') + return + except Exception, e: + self._log(DEBUG, 'Exception on channel: ' + str(e)) + self._log(DEBUG, util.tb_strings()) + return + msg = Message(data) + request_number = msg.get_int() + self._process(t, request_number, msg) + + def finish_subsystem(self): + self.server.session_ended() + # close any file handles that were left open (so we can return them to the OS quickly) + for f in self.file_table.itervalues(): + f.close() + for f in self.folder_table.itervalues(): + f.close() + self.file_table = {} + self.folder_table = {} + + def convert_errno(e): + """ + Convert an errno value (as from an C{OSError} or C{IOError}) into a + standard SFTP result code. This is a convenience function for trapping + exceptions in server code and returning an appropriate result. + + @param e: an errno code, as from C{OSError.errno}. + @type e: int + @return: an SFTP error code like L{SFTP_NO_SUCH_FILE}. + @rtype: int + """ + if e == errno.EACCES: + # permission denied + return SFTP_PERMISSION_DENIED + elif e == errno.ENOENT: + # no such file + return SFTP_NO_SUCH_FILE + else: + return SFTP_FAILURE + convert_errno = staticmethod(convert_errno) + + def set_file_attr(filename, attr): + """ + Change a file's attributes on the local filesystem. The contents of + C{attr} are used to change the permissions, owner, group ownership, + and/or modification & access time of the file, depending on which + attributes are present in C{attr}. + + This is meant to be a handy helper function for translating SFTP file + requests into local file operations. + + @param filename: name of the file to alter (should usually be an + absolute path). + @type filename: str + @param attr: attributes to change. + @type attr: L{SFTPAttributes} + """ + if attr._flags & attr.FLAG_PERMISSIONS: + os.chmod(filename, attr.st_mode) + if attr._flags & attr.FLAG_UIDGID: + os.chown(filename, attr.st_uid, attr.st_gid) + if attr._flags & attr.FLAG_AMTIME: + os.utime(filename, (attr.st_atime, attr.st_mtime)) + set_file_attr = staticmethod(set_file_attr) + + + ### internals... + + + def _response(self, request_number, t, *arg): + msg = Message() + msg.add_int(request_number) + for item in arg: + if type(item) is int: + msg.add_int(item) + elif type(item) is long: + msg.add_int64(item) + elif type(item) is str: + msg.add_string(item) + elif type(item) is SFTPAttributes: + item._pack(msg) + else: + raise Exception('unknown type for ' + repr(item) + ' type ' + repr(type(item))) + self._send_packet(t, str(msg)) + + def _send_handle_response(self, request_number, handle, folder=False): + if not issubclass(type(handle), SFTPHandle): + # must be error code + self._send_status(request_number, handle) + return + handle._set_name('hx%d' % self.next_handle) + self.next_handle += 1 + if folder: + self.folder_table[handle._get_name()] = handle + else: + self.file_table[handle._get_name()] = handle + self._response(request_number, CMD_HANDLE, handle._get_name()) + + def _send_status(self, request_number, code, desc=None): + if desc is None: + desc = SFTP_DESC[code] + self._response(request_number, CMD_STATUS, code, desc) + + def _open_folder(self, request_number, path): + resp = self.server.list_folder(path) + if issubclass(type(resp), list): + # got an actual list of filenames in the folder + folder = SFTPHandle() + folder._set_files(resp) + self._send_handle_response(request_number, folder, True) + return + # must be an error code + self._send_status(request_number, resp) + + def _read_folder(self, request_number, folder): + flist = folder._get_next_files() + if len(flist) == 0: + self._send_status(request_number, SFTP_EOF) + return + msg = Message() + msg.add_int(request_number) + msg.add_int(len(flist)) + for attr in flist: + msg.add_string(attr.filename) + msg.add_string(str(attr)) + attr._pack(msg) + self._send_packet(CMD_NAME, str(msg)) + + def _check_file(self, request_number, msg): + # this extension actually comes from v6 protocol, but since it's an + # extension, i feel like we can reasonably support it backported. + # it's very useful for verifying uploaded files or checking for + # rsync-like differences between local and remote files. + handle = msg.get_string() + alg_list = msg.get_list() + start = msg.get_int64() + length = msg.get_int64() + block_size = msg.get_int() + if not self.file_table.has_key(handle): + self._send_status(request_number, SFTP_BAD_MESSAGE, 'Invalid handle') + return + f = self.file_table[handle] + for x in alg_list: + if x in _hash_class: + algname = x + alg = _hash_class[x] + break + else: + self._send_status(request_number, SFTP_FAILURE, 'No supported hash types found') + return + if length == 0: + st = f.stat() + if not issubclass(type(st), SFTPAttributes): + self._send_status(request_number, st, 'Unable to stat file') + return + length = st.st_size - start + if block_size == 0: + block_size = length + if block_size < 256: + self._send_status(request_number, SFTP_FAILURE, 'Block size too small') + return + + sum = '' + offset = start + while offset < start + length: + blocklen = min(block_size, start + length - offset) + # don't try to read more than about 64KB at a time + chunklen = min(blocklen, 65536) + count = 0 + hash = alg.new() + while count < blocklen: + data = f.read(offset, chunklen) + if not type(data) is str: + self._send_status(request_number, data, 'Unable to hash file') + return + hash.update(data) + count += len(data) + offset += count + sum += hash.digest() + + msg = Message() + msg.add_int(request_number) + msg.add_string('check-file') + msg.add_string(algname) + msg.add_bytes(sum) + self._send_packet(CMD_EXTENDED_REPLY, str(msg)) + + def _convert_pflags(self, pflags): + "convert SFTP-style open() flags to python's os.open() flags" + if (pflags & SFTP_FLAG_READ) and (pflags & SFTP_FLAG_WRITE): + flags = os.O_RDWR + elif pflags & SFTP_FLAG_WRITE: + flags = os.O_WRONLY + else: + flags = os.O_RDONLY + if pflags & SFTP_FLAG_APPEND: + flags |= os.O_APPEND + if pflags & SFTP_FLAG_CREATE: + flags |= os.O_CREAT + if pflags & SFTP_FLAG_TRUNC: + flags |= os.O_TRUNC + if pflags & SFTP_FLAG_EXCL: + flags |= os.O_EXCL + return flags + + def _process(self, t, request_number, msg): + self._log(DEBUG, 'Request: %s' % CMD_NAMES[t]) + if t == CMD_OPEN: + path = msg.get_string() + flags = self._convert_pflags(msg.get_int()) + attr = SFTPAttributes._from_msg(msg) + self._send_handle_response(request_number, self.server.open(path, flags, attr)) + elif t == CMD_CLOSE: + handle = msg.get_string() + if self.folder_table.has_key(handle): + del self.folder_table[handle] + self._send_status(request_number, SFTP_OK) + return + if self.file_table.has_key(handle): + self.file_table[handle].close() + del self.file_table[handle] + self._send_status(request_number, SFTP_OK) + return + self._send_status(request_number, SFTP_BAD_MESSAGE, 'Invalid handle') + elif t == CMD_READ: + handle = msg.get_string() + offset = msg.get_int64() + length = msg.get_int() + if not self.file_table.has_key(handle): + self._send_status(request_number, SFTP_BAD_MESSAGE, 'Invalid handle') + return + data = self.file_table[handle].read(offset, length) + if type(data) is str: + if len(data) == 0: + self._send_status(request_number, SFTP_EOF) + else: + self._response(request_number, CMD_DATA, data) + else: + self._send_status(request_number, data) + elif t == CMD_WRITE: + handle = msg.get_string() + offset = msg.get_int64() + data = msg.get_string() + if not self.file_table.has_key(handle): + self._send_status(request_number, SFTP_BAD_MESSAGE, 'Invalid handle') + return + self._send_status(request_number, self.file_table[handle].write(offset, data)) + elif t == CMD_REMOVE: + path = msg.get_string() + self._send_status(request_number, self.server.remove(path)) + elif t == CMD_RENAME: + oldpath = msg.get_string() + newpath = msg.get_string() + self._send_status(request_number, self.server.rename(oldpath, newpath)) + elif t == CMD_MKDIR: + path = msg.get_string() + attr = SFTPAttributes._from_msg(msg) + self._send_status(request_number, self.server.mkdir(path, attr)) + elif t == CMD_RMDIR: + path = msg.get_string() + self._send_status(request_number, self.server.rmdir(path)) + elif t == CMD_OPENDIR: + path = msg.get_string() + self._open_folder(request_number, path) + return + elif t == CMD_READDIR: + handle = msg.get_string() + if not self.folder_table.has_key(handle): + self._send_status(request_number, SFTP_BAD_MESSAGE, 'Invalid handle') + return + folder = self.folder_table[handle] + self._read_folder(request_number, folder) + elif t == CMD_STAT: + path = msg.get_string() + resp = self.server.stat(path) + if issubclass(type(resp), SFTPAttributes): + self._response(request_number, CMD_ATTRS, resp) + else: + self._send_status(request_number, resp) + elif t == CMD_LSTAT: + path = msg.get_string() + resp = self.server.lstat(path) + if issubclass(type(resp), SFTPAttributes): + self._response(request_number, CMD_ATTRS, resp) + else: + self._send_status(request_number, resp) + elif t == CMD_FSTAT: + handle = msg.get_string() + if not self.file_table.has_key(handle): + self._send_status(request_number, SFTP_BAD_MESSAGE, 'Invalid handle') + return + resp = self.file_table[handle].stat() + if issubclass(type(resp), SFTPAttributes): + self._response(request_number, CMD_ATTRS, resp) + else: + self._send_status(request_number, resp) + elif t == CMD_SETSTAT: + path = msg.get_string() + attr = SFTPAttributes._from_msg(msg) + self._send_status(request_number, self.server.chattr(path, attr)) + elif t == CMD_FSETSTAT: + handle = msg.get_string() + attr = SFTPAttributes._from_msg(msg) + if not self.file_table.has_key(handle): + self._response(request_number, SFTP_BAD_MESSAGE, 'Invalid handle') + return + self._send_status(request_number, self.file_table[handle].chattr(attr)) + elif t == CMD_READLINK: + path = msg.get_string() + resp = self.server.readlink(path) + if type(resp) is str: + self._response(request_number, CMD_NAME, 1, resp, '', SFTPAttributes()) + else: + self._send_status(request_number, resp) + elif t == CMD_SYMLINK: + # the sftp 2 draft is incorrect here! path always follows target_path + target_path = msg.get_string() + path = msg.get_string() + self._send_status(request_number, self.server.symlink(target_path, path)) + elif t == CMD_REALPATH: + path = msg.get_string() + rpath = self.server.canonicalize(path) + self._response(request_number, CMD_NAME, 1, rpath, '', SFTPAttributes()) + elif t == CMD_EXTENDED: + tag = msg.get_string() + if tag == 'check-file': + self._check_file(request_number, msg) + else: + send._send_status(request_number, SFTP_OP_UNSUPPORTED) + else: + self._send_status(request_number, SFTP_OP_UNSUPPORTED) + + +from paramiko.sftp_handle import SFTPHandle |