handle various permission failures

- turn various EPERM, EACCES errors into 403
- add `writable` bool field to contents models
- if a notebook is not `writable`, save is disabled

IPython/html/services/contents/filemanager.py

@@ -4,10 +4,11 b''
 # Distributed under the terms of the Modified BSD License.
 
 import base64
+import errno
 import io
 import os
-import glob
 import shutil
+from contextlib import contextmanager
 
 from tornado import web
 
@@ -16,9 +17,9 b' from IPython import nbformat'
 from IPython.utils.io import atomic_writing
 from IPython.utils.path import ensure_dir_exists
 from IPython.utils.traitlets import Unicode, Bool, TraitError
-from IPython.utils.py3compat import getcwd
+from IPython.utils.py3compat import getcwd, str_to_unicode
 from IPython.utils import tz
-from IPython.html.utils import is_hidden, to_os_path, url_path_join
+from IPython.html.utils import is_hidden, to_os_path, to_api_path
 
 
 class FileContentsManager(ContentsManager):
@@ -30,7 +31,38 b' class FileContentsManager(ContentsManager):'
             return self.parent.notebook_dir
         except AttributeError:
             return getcwd()
-
+    
+    @contextmanager
+    def perm_to_403(self, os_path=''):
+        """context manager for turning permission errors into 403"""
+        try:
+            yield
+        except OSError as e:
+            if e.errno in {errno.EPERM, errno.EACCES}:
+                # make 403 error message without root prefix
+                # this may not work perfectly on unicode paths on Python 2,
+                # but nobody should be doing that anyway.
+                if not os_path:
+                    os_path = str_to_unicode(e.filename or 'unknown file')
+                path = to_api_path(os_path, self.root_dir)
+                raise web.HTTPError(403, u'Permission denied: %s' % path)
+            else:
+                raise
+    
+    @contextmanager
+    def open(self, os_path, *args, **kwargs):
+        """wrapper around io.open that turns permission errors into 403"""
+        with self.perm_to_403(os_path):
+            with io.open(os_path, *args, **kwargs) as f:
+                yield f
+    
+    @contextmanager
+    def open_w(self, os_path, *args, **kwargs):
+        """wrapper around atomic_writing that turns permission errors into 403"""
+        with self.perm_to_403(os_path):
+            with atomic_writing(os_path, *args, **kwargs) as f:
+                yield f
+    
     save_script = Bool(False, config=True, help='DEPRECATED, IGNORED')
     def _save_script_changed(self):
         self.log.warn("""
@@ -172,6 +204,11 b' class FileContentsManager(ContentsManager):'
         model['created'] = created
         model['content'] = None
         model['format'] = None
+        try:
+            model['writable'] = os.access(os_path, os.W_OK)
+        except OSError:
+            self.log.error("Failed to check write permissions on %s", os_path)
+            model['writable'] = False
         return model
 
     def _dir_model(self, path, content=True):
@@ -181,7 +218,7 b' class FileContentsManager(ContentsManager):'
         """
         os_path = self._get_os_path(path)
 
-        four_o_four = u'directory does not exist: %r' % os_path
+        four_o_four = u'directory does not exist: %r' % path
 
         if not os.path.isdir(os_path):
             raise web.HTTPError(404, four_o_four)
@@ -232,7 +269,7 b' class FileContentsManager(ContentsManager):'
             if not os.path.isfile(os_path):
                 # could be FIFO
                 raise web.HTTPError(400, "Cannot get content of non-file %s" % os_path)
-            with io.open(os_path, 'rb') as f:
+            with self.open(os_path, 'rb') as f:
                 bcontent = f.read()
 
             if format != 'base64':
@@ -261,7 +298,7 b' class FileContentsManager(ContentsManager):'
         model['type'] = 'notebook'
         if content:
             os_path = self._get_os_path(path)
-            with io.open(os_path, 'r', encoding='utf-8') as f:
+            with self.open(os_path, 'r', encoding='utf-8') as f:
                 try:
                     nb = nbformat.read(f, as_version=4)
                 except Exception as e:
@@ -321,7 +358,7 b' class FileContentsManager(ContentsManager):'
 
         self.check_and_sign(nb, path)
 
-        with atomic_writing(os_path, encoding='utf-8') as f:
+        with self.open_w(os_path, encoding='utf-8') as f:
             nbformat.write(nb, f, version=nbformat.NO_CONVERT)
 
     def _save_file(self, os_path, model, path=''):
@@ -338,7 +375,7 b' class FileContentsManager(ContentsManager):'
                 bcontent = base64.decodestring(b64_bytes)
         except Exception as e:
             raise web.HTTPError(400, u'Encoding error saving %s: %s' % (os_path, e))
-        with atomic_writing(os_path, text=False) as f:
+        with self.open_w(os_path, text=False) as f:
             f.write(bcontent)
 
     def _save_directory(self, os_path, model, path=''):
@@ -346,7 +383,8 b' class FileContentsManager(ContentsManager):'
         if is_hidden(os_path, self.root_dir):
             raise web.HTTPError(400, u'Cannot create hidden directory %r' % os_path)
         if not os.path.exists(os_path):
-            os.mkdir(os_path)
+            with self.perm_to_403():
+                os.mkdir(os_path)
         elif not os.path.isdir(os_path):
             raise web.HTTPError(400, u'Not a directory: %s' % (os_path))
         else:
@@ -379,7 +417,8 b' class FileContentsManager(ContentsManager):'
         except web.HTTPError:
             raise
         except Exception as e:
-            raise web.HTTPError(400, u'Unexpected error while saving file: %s %s' % (os_path, e))
+            self.log.error(u'Error while saving file: %s %s', path, e, exc_info=True)
+            raise web.HTTPError(500, u'Unexpected error while saving file: %s %s' % (path, e))
 
         validation_message = None
         if model['type'] == 'notebook':
@@ -423,14 +462,17 b' class FileContentsManager(ContentsManager):'
             cp_path = self.get_checkpoint_path(checkpoint_id, path)
             if os.path.isfile(cp_path):
                 self.log.debug("Unlinking checkpoint %s", cp_path)
-                os.unlink(cp_path)
+                with self.perm_to_403():
+                    rm(cp_path)
 
         if os.path.isdir(os_path):
             self.log.debug("Removing directory %s", os_path)
-            shutil.rmtree(os_path)
+            with self.perm_to_403():
+                shutil.rmtree(os_path)
         else:
             self.log.debug("Unlinking file %s", os_path)
-            rm(os_path)
+            with self.perm_to_403():
+                rm(os_path)
 
     def rename(self, old_path, new_path):
         """Rename a file."""
@@ -448,7 +490,10 b' class FileContentsManager(ContentsManager):'
 
         # Move the file
         try:
-            shutil.move(old_os_path, new_os_path)
+            with self.perm_to_403():
+                shutil.move(old_os_path, new_os_path)
+        except web.HTTPError:
+            raise
         except Exception as e:
             raise web.HTTPError(500, u'Unknown error renaming file: %s %s' % (old_path, e))
 
@@ -460,7 +505,8 b' class FileContentsManager(ContentsManager):'
             new_cp_path = self.get_checkpoint_path(checkpoint_id, new_path)
             if os.path.isfile(old_cp_path):
                 self.log.debug("Renaming checkpoint %s -> %s", old_cp_path, new_cp_path)
-                shutil.move(old_cp_path, new_cp_path)
+                with self.perm_to_403():
+                    shutil.move(old_cp_path, new_cp_path)
 
     # Checkpoint-related utilities
 
@@ -477,7 +523,8 b' class FileContentsManager(ContentsManager):'
         )
         os_path = self._get_os_path(path=parent)
         cp_dir = os.path.join(os_path, self.checkpoint_dir)
-        ensure_dir_exists(cp_dir)
+        with self.perm_to_403():
+            ensure_dir_exists(cp_dir)
         cp_path = os.path.join(cp_dir, filename)
         return cp_path
 
@@ -505,7 +552,8 b' class FileContentsManager(ContentsManager):'
         checkpoint_id = u"checkpoint"
         cp_path = self.get_checkpoint_path(checkpoint_id, path)
         self.log.debug("creating checkpoint for %s", path)
-        self._copy(src_path, cp_path)
+        with self.perm_to_403():
+            self._copy(src_path, cp_path)
 
         # return the checkpoint info
         return self.get_checkpoint_model(checkpoint_id, path)
@@ -537,10 +585,11 b' class FileContentsManager(ContentsManager):'
             )
         # ensure notebook is readable (never restore from an unreadable notebook)
         if cp_path.endswith('.ipynb'):
-            with io.open(cp_path, 'r', encoding='utf-8') as f:
+            with self.open(cp_path, 'r', encoding='utf-8') as f:
                 nbformat.read(f, as_version=4)
-        self._copy(cp_path, nb_path)
         self.log.debug("copying %s -> %s", cp_path, nb_path)
+        with self.perm_to_403():
+            self._copy(cp_path, nb_path)
 
     def delete_checkpoint(self, checkpoint_id, path):
         """delete a file's checkpoint"""

IPython/html/static/notebook/js/notebook.js

@@ -110,7 +110,7 b' define(['
                             CodeMirror.runMode(code, mode, el);
                             callback(null, el.innerHTML);
                         } catch (err) {
-                            console.log("Failed to highlight " + lang + " code", error);
+                            console.log("Failed to highlight " + lang + " code", err);
                             callback(err, code);
                         }
                     }, function (err) {
@@ -132,6 +132,7 b' define(['
         this.undelete_index = null;
         this.undelete_below = false;
         this.paste_enabled = false;
+        this.writable = false;
         // It is important to start out in command mode to match the intial mode
         // of the KeyboardManager.
         this.mode = 'command';
@@ -1896,6 +1897,10 b' define(['
         if (this.autosave_timer) {
             clearInterval(this.autosave_timer);
         }
+        if (!this.writable) {
+            // disable autosave if not writable
+            interval = 0;
+        }
         
         this.autosave_interval = this.minimum_autosave_interval = interval;
         if (interval) {
@@ -1918,12 +1923,18 b' define(['
      * @method save_notebook
      */
     Notebook.prototype.save_notebook = function () {
-        if(!this._fully_loaded){
+        if (!this._fully_loaded) {
             this.events.trigger('notebook_save_failed.Notebook',
                 new Error("Load failed, save is disabled")
             );
             return;
+        } else if (!this.writable) {
+            this.events.trigger('notebook_save_failed.Notebook',
+                new Error("Notebook is read-only")
+            );
+            return;
         }
+
         // Create a JSON model to be sent to the server.
         var model = {
             type : "notebook",
@@ -2052,7 +2063,8 b' define(['
         });
     };
 
-    Notebook.prototype.copy_notebook = function(){
+    Notebook.prototype.copy_notebook = function () {
+        var that = this;
         var base_url = this.base_url;
         var w = window.open();
         var parent = utils.url_path_split(this.notebook_path)[0];
@@ -2064,7 +2076,7 b' define(['
             },
             function(error) {
                 w.close();
-                console.log(error);
+                that.events.trigger('notebook_copy_failed', error);
             }
         );
     };
@@ -2175,6 +2187,7 b' define(['
         }
         this.set_dirty(false);
         this.scroll_to_top();
+        this.writable = data.writable || false;
         var nbmodel = data.content;
         var orig_nbformat = nbmodel.metadata.orig_nbformat;
         var orig_nbformat_minor = nbmodel.metadata.orig_nbformat_minor;
@@ -2249,7 +2262,12 b' define(['
         } else {
             celltoolbar.CellToolbar.global_hide();
         }
-
+        
+        if (!this.writable) {
+            this.set_autosave_interval(0);
+            this.events.trigger('notebook_read_only.Notebook');
+        }
+        
         // now that we're fully loaded, it is safe to restore save functionality
         this._fully_loaded = true;
         this.events.trigger('notebook_loaded.Notebook');

IPython/html/static/notebook/js/notificationarea.js

@@ -340,8 +340,11 b' define(['
         this.events.on('notebook_saved.Notebook', function () {
             nnw.set_message("Notebook saved",2000);
         });
-        this.events.on('notebook_save_failed.Notebook', function (evt, xhr, status, data) {
-            nnw.warning(data || "Notebook save failed");
+        this.events.on('notebook_save_failed.Notebook', function (evt, error) {
+            nnw.warning(error.message || "Notebook save failed");
+        });
+        this.events.on('notebook_copy_failed.Notebook', function (evt, error) {
+            nnw.warning(error.message || "Notebook copy failed");
         });
         
         // Checkpoint events

IPython/html/static/notebook/js/savewidget.js

@@ -46,6 +46,11 b' define(['
         this.events.on('notebook_save_failed.Notebook', function () {
             that.set_save_status('Autosave Failed!');
         });
+        this.events.on('notebook_read_only.Notebook', function () {
+            that.set_save_status('(read only)');
+            // disable future set_save_status
+            that.set_save_status = function () {};
+        });
         this.events.on('checkpoints_listed.Notebook', function (event, data) {
             that._set_last_checkpoint(data[0]);
         });

IPython/html/utils.py

@@ -1,16 +1,7 b''
-"""Notebook related utilities
+"""Notebook related utilities"""
 
-Authors:
-
-* Brian Granger
-"""
-
-#-----------------------------------------------------------------------------
-#  Copyright (C) 2011  The IPython Development Team
-#
-#  Distributed under the terms of the BSD License.  The full license is in
-#  the file COPYING, distributed as part of this software.
-#-----------------------------------------------------------------------------
+# Copyright (c) IPython Development Team.
+# Distributed under the terms of the Modified BSD License.
 
 from __future__ import print_function
 
@@ -28,9 +19,6 b' from IPython.utils import py3compat'
 # It is used by BSD to indicate hidden files.
 UF_HIDDEN = getattr(stat, 'UF_HIDDEN', 32768)
 
-#-----------------------------------------------------------------------------
-# Imports
-#-----------------------------------------------------------------------------
 
 def url_path_join(*pieces):
     """Join components of url into a relative url
@@ -137,4 +125,17 b" def to_os_path(path, root=''):"
     parts = [p for p in parts if p != ''] # remove duplicate splits
     path = os.path.join(root, *parts)
     return path
+
+def to_api_path(os_path, root=''):
+    """Convert a filesystem path to an API path
     
+    If given, root will be removed from the path.
+    root must be a filesystem path already.
+    """
+    if os_path.startswith(root):
+        os_path = os_path[len(root):]
+    parts = os_path.strip(os.path.sep).split(os.path.sep)
+    parts = [p for p in parts if p != ''] # remove duplicate splits
+    path = '/'.join(parts)
+    return path
+