Add external extensions json source in proper mac location.

base/file_util_posix.cc

Index: base/file_util_posix.cc
diff --git a/base/file_util_posix.cc b/base/file_util_posix.cc
index 9904584abd3c0fa9059c7ce1f276caaa9642b065..1678ce466626f0ec3e833a94b97b78100bb441e6 100644
--- a/base/file_util_posix.cc
+++ b/base/file_util_posix.cc
@@ -940,4 +940,45 @@ bool CopyFile(const FilePath& from_path, const FilePath& to_path) {
 }
 #endif  // defined(OS_MACOSX)
 
+// Test that a path is owned by a specific user, and not writable
+// by all users.  This is useful for checking that a config file
+// is administrator-controlled.  All components of |path| after |base|
+// are checked.  Note that |base| is not checked, and |base| must be a
+// parent of |path|.

[Evan Martin, 2011/08/24 22:38:53]

These comments belong in the header.

[Sam Kerner (Chrome), 2011/08/25 14:04:37]

Done.

+bool IsPathControlledByUser(const FilePath& base,
+                            const FilePath& path,
+                            uid_t owner_uid) {
+  if (path == base)

[TVL, 2011/08/25 14:07:28]

do you need to sanity check that base is the prefix of path?  also, what happens
if you get "" for base?

[Sam Kerner (Chrome), 2011/08/26 19:59:15]

Sanity checks added.  Unit test IsPathControlledByUserTest.BadPaths now covers
both cases.

+    return true;
+
+

[Evan Martin, 2011/08/24 22:38:53]

Is the double-newline here intentional?

[Sam Kerner (Chrome), 2011/08/25 14:04:37]

No.  Removed.

+  if (!IsPathControlledByUser(base, path.DirName(), owner_uid))

[TVL, 2011/08/25 14:07:28]

could this be done with a loop to avoid the recursion?  not sure how large of
paths you'll get, but if it's stuff within a users profile, seems like it could
be pretty deep.

[Sam Kerner (Chrome), 2011/08/26 19:59:15]

Done.

+    return false;
+
+  stat_wrapper_t stat_info;
+  if (CallStat(path.value().c_str(), &stat_info) != 0) {
+    LOG(ERROR) << "Failed to get information on path " << path.value();

[Evan Martin, 2011/08/24 22:38:53]

Use PLOG() for functions like this that use errno

[Sam Kerner (Chrome), 2011/08/25 14:04:37]

Done.

+    return false;
+  }
+
+  if (stat_info.st_uid != owner_uid) {
+    LOG(ERROR) << "Path " << path.value()
+               << " is owned by the wrong user.";
+    return false;
+  }
+
+  if (stat_info.st_mode & S_IWOTH) {
+    LOG(ERROR) << "Path "<< path.value() << " is writable by any user.";
+    return false;
+  }
+
+  return true;
+}
+
+bool IsPathControlledByAdmin(const FilePath& path) {
+  const unsigned kRootUid = 0;
+  const FilePath kFileSystemRoot(FILE_PATH_LITERAL("/"));

[Evan Martin, 2011/08/24 22:38:53]

Since this is in POSIX code, you can use "/" without FILE_PATH_LITERAL around it

[Sam Kerner (Chrome), 2011/08/25 14:04:37]

Done.

+  return IsPathControlledByUser(kFileSystemRoot, path, kRootUid);
+}
+
 }  // namespace file_util