Merge pull request #7 from tschaub/permission

Handle permissions on POSIX-compliant systems.
tschaub · Feb 4, 2014 · 1cabbb4 · 1cabbb4
2 parents 61a2c84 + b2ad517
commit 1cabbb4
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Showing 7 changed files with 470 additions and 10 deletions.
diff --git a/lib/binding.js b/lib/binding.js
@@ -284,11 +284,21 @@ Binding.prototype.open = function(pathname, flags, mode, callback) {
         throw new FSError('ENOTDIR', pathname);
       }
       item = new File();
-      item.setMode(mode);
+      if (mode) {
+        item.setMode(mode);
+      }
       parent.addItem(path.basename(pathname), item);
     }
-    if (descriptor.isRead() && !item) {
-      throw new FSError('ENOENT', pathname);
+    if (descriptor.isRead()) {
+      if (!item) {
+        throw new FSError('ENOENT', pathname);
+      }
+      if (!item.canRead()) {
+        throw new FSError('EACCES', pathname);
+      }
+    }
+    if (descriptor.isWrite() && !item.canWrite()) {
+      throw new FSError('EACCES', pathname);
     }
     if (descriptor.isTruncate()) {
       item.setContent('');
@@ -506,7 +516,9 @@ Binding.prototype.mkdir = function(pathname, mode, callback) {
       throw new FSError('ENOENT', pathname);
     }
     var dir = new Directory();
-    dir.setMode(mode);
+    if (mode) {
+      dir.setMode(mode);
+    }
     parent.addItem(path.basename(pathname), dir);
   });
 };

diff --git a/lib/directory.js b/lib/directory.js
@@ -20,6 +20,11 @@ function Directory() {
    */
   this._items = {};
 
+  /**
+   * Permissions.
+   */
+  this._mode = 0777;
+
 }
 util.inherits(Directory, Item);
 

diff --git a/lib/filesystem.js b/lib/filesystem.js
@@ -3,6 +3,7 @@ var path = require('path');
 
 var Directory = require('./directory');
 var File = require('./file');
+var FSError = require('./error');
 var SymbolicLink = require('./symlink');
 
 
@@ -69,9 +70,18 @@ function FileSystem() {
  */
 FileSystem.prototype.getItem = function(filepath) {
   var parts = getPathParts(filepath);
+  var currentParts = getPathParts(process.cwd());
   var item = this._root;
+  var name;
   for (var i = 0, ii = parts.length; i < ii; ++i) {
-    item = item.getItem(parts[i]);
+    name = parts[i];
+    if (item instanceof Directory && name !== currentParts[i]) {
+      // make sure traversal is allowed
+      if (!item.canExecute()) {
+        throw new FSError('EACCES', filepath);
+      }
+    }
+    item = item.getItem(name);
     if (!item) {
       break;
     }
@@ -233,8 +243,6 @@ FileSystem.directory = function(config) {
     var dir = new Directory();
     if (config.hasOwnProperty('mode')) {
       dir.setMode(config.mode);
-    } else {
-      dir.setMode(0777);
     }
     if (config.hasOwnProperty('uid')) {
       dir.setUid(config.uid);

diff --git a/lib/item.js b/lib/item.js
@@ -3,6 +3,31 @@ var path = require('path');
 var counter = 0;
 
 
+/**
+ * Permissions.
+ * @enum {number}
+ */
+var permissions = {
+  USER_READ: 256, // 0400
+  USER_WRITE: 128, // 0200
+  USER_EXEC: 64, // 0100
+  GROUP_READ: 32, // 0040
+  GROUP_WRITE: 16, // 0020
+  GROUP_EXEC: 8, // 0010
+  OTHER_READ: 4, // 0004
+  OTHER_WRITE: 2, // 0002
+  OTHER_EXEC: 1 // 0001
+};
+
+function getUid() {
+  return process.getuid && process.getuid();
+}
+
+function getGid() {
+  return process.getgid && process.getgid();
+}
+
+
 
 /**
  * A filesystem item.
@@ -39,13 +64,13 @@ function Item() {
    * User id.
    * @type {number}
    */
-  this._uid = process.getuid ? process.getuid() : undefined;
+  this._uid = getUid();
 
   /**
    * Group id.
    * @type {number}
    */
-  this._gid = process.getgid ? process.getgid() : undefined;
+  this._gid = getGid();
 
   /**
    * Item number.
@@ -61,6 +86,69 @@ function Item() {
 }
 
 
+/**
+ * Determine if the current user has read permission.
+ * @return {boolean} The current user can read.
+ */
+Item.prototype.canRead = function() {
+  var uid = getUid();
+  var gid = getGid();
+  var can = false;
+  if (uid === 0) {
+    can = true;
+  } else if (uid === this._uid) {
+    can = (permissions.USER_READ & this._mode) === permissions.USER_READ;
+  } else if (gid === this._gid) {
+    can = (permissions.GROUP_READ & this._mode) === permissions.GROUP_READ;
+  } else {
+    can = (permissions.OTHER_READ & this._mode) === permissions.OTHER_READ;
+  }
+  return can;
+};
+
+
+/**
+ * Determine if the current user has write permission.
+ * @return {boolean} The current user can write.
+ */
+Item.prototype.canWrite = function() {
+  var uid = getUid();
+  var gid = getGid();
+  var can = false;
+  if (uid === 0) {
+    can = true;
+  } else if (uid === this._uid) {
+    can = (permissions.USER_WRITE & this._mode) === permissions.USER_WRITE;
+  } else if (gid === this._gid) {
+    can = (permissions.GROUP_WRITE & this._mode) === permissions.GROUP_WRITE;
+  } else {
+    can = (permissions.OTHER_WRITE & this._mode) === permissions.OTHER_WRITE;
+  }
+  return can;
+};
+
+
+/**
+ * Determine if the current user has execute permission.
+ * @return {boolean} The current user can execute.
+ */
+Item.prototype.canExecute = function() {
+  var uid = getUid();
+  var gid = getGid();
+  var can = false;
+  if (uid === 0) {
+    can = true;
+  } else if (uid === this._uid) {
+    can = (permissions.USER_EXEC & this._mode) === permissions.USER_EXEC;
+  } else if (gid === this._gid) {
+    can = (permissions.GROUP_EXEC & this._mode) === permissions.GROUP_EXEC;
+  } else {
+    can = (permissions.OTHER_EXEC & this._mode) === permissions.OTHER_EXEC;
+  }
+  return can;
+};
+
+
 /**
  * Get access time.
  * @return {Date} Access time.
@@ -187,7 +275,7 @@ Item.prototype.getStats = function() {
     ino: this._id,
     atime: this.getATime(),
     mtime: this.getMTime(),
-    ctime: this.getCTime(),
+    ctime: this.getCTime()
   };
 };
 

diff --git a/readme.md b/readme.md
@@ -186,6 +186,8 @@ The following [`fs` functions](http://nodejs.org/api/fs.html) are overridden: `f
 
 Mock `fs.Stats` objects have the following properties: `dev`, `ino`, `nlink`, `mode`, `size`, `rdev`, `blksize`, `blocks`, `atime`, `ctime`, `mtime`, `uid`, and `gid`.  In addition, all of the `is*()` method are provided (e.g. `isDirectory()`, `isFile()`, et al.).
 
+Mock file access is controlled based on file mode where `process.getuid()` and `process.getgid()` are available (POSIX systems).  On other systems (e.g. Windows) the file mode has no effect.
+
 The following `fs` functions are *not* currently mocked (if your tests use these, they will work against the real file system): `fs.FSWatcher`, `fs.unwatchFile`, `fs.watch`, and `fs.watchFile`.  Pull requests welcome.
 
 Tested on Linux, OSX, and Windows using Node 0.8, 0.9, 0.10, and 0.11.  Check the tickets for a list of [known issues](https://github.com/tschaub/mock-fs/issues).

diff --git a/test/lib/index.spec.js b/test/lib/index.spec.js
@@ -2503,4 +2503,106 @@ describe('Mocking the file system', function() {
 
   });
 
+  if (process.getuid && process.getgid) {
+
+    describe('security', function() {
+
+      afterEach(mock.restore);
+
+      it('denies dir listing without execute on parent', function() {
+
+        mock({
+          secure: mock.directory({
+            mode: 0666,
+            items: {
+              insecure: ({
+                file: 'file content'
+              })
+            }
+          })
+        });
+
+        var err;
+        try {
+          fs.readdirSync('secure/insecure');
+        } catch (e) {
+          err = e;
+        }
+        assert.instanceOf(err, Error);
+        assert.equal(err.code, 'EACCES');
+
+      });
+
+      it('denies file read without execute on parent', function() {
+
+        mock({
+          secure: mock.directory({
+            mode: 0666,
+            items: {
+              insecure: ({
+                file: 'file content'
+              })
+            }
+          })
+        });
+
+        var err;
+        try {
+          fs.readFileSync('secure/insecure/file');
+        } catch (e) {
+          err = e;
+        }
+        assert.instanceOf(err, Error);
+        assert.equal(err.code, 'EACCES');
+
+      });
+
+      it('denies file read without read on file', function() {
+
+        mock({
+          insecure: ({
+            'write-only': mock.file({
+              mode: 0222,
+              content: 'write only'
+            })
+          })
+        });
+
+        var err;
+        try {
+          fs.readFileSync('insecure/write-only');
+        } catch (e) {
+          err = e;
+        }
+        assert.instanceOf(err, Error);
+        assert.equal(err.code, 'EACCES');
+
+      });
+
+      it('denies file write without write on file', function() {
+
+        mock({
+          insecure: ({
+            'read-only': mock.file({
+              mode: 0444,
+              content: 'read only'
+            })
+          })
+        });
+
+        var err;
+        try {
+          fs.writeFileSync('insecure/read-only', 'denied');
+        } catch (e) {
+          err = e;
+        }
+        assert.instanceOf(err, Error);
+        assert.equal(err.code, 'EACCES');
+
+      });
+
+    });
+
+  }
+
 });