Details

This patch replaces disrecommended os.access() usage with recommended feckless open.

os.access(...W_OK...) does not report whether or not the current process is able to write. Rather it reports whether the login process (i.e. web server agent) is able to write.

setuid(2) and setgid(2) are a pair of unix security tools that grant privilege limited by a selected office (i.e. virtual user). Offices are created to separate privilege grants (i.e. Mail server office can read/write mail files but cannot nominally read/write web files. Web server agent can nominally read web pages but only web editor can nominally write web pages.).

A company intranet web server (e.g. apache) is likely to use unprivileged agents (e.g. wwwrun) and grant access to secure services (e.g. bug tracking or wiki) via gateways (i.e. specially designated executable files). setgid(2) grants limited privilege (e.g. access to bug files or wiki files, but not both) individually to each of these gateways.

Improper use of os.access() in Page.py prevents adding pages or saving changes if moin.cgi is installed under setuid wrapper.

The danger of granting write privilege to the web server agent is that it gives wiki file ownership to the web server agent and so overrides wiki security settings. Denying write privilege to the web server agent, without this patch, prevents the wiki from adding or changing pages.

Patch

Rather than mark a page immutable if the web server cannot write it, mark it immutable if an attempt to open it (for appending nothing) fails.

Toggle line numbers 
   1 --- moin-1.8.2/MoinMoin/Page.py	2009-02-07 20:31:01.000000000 -0500
   2 +++ moin-1.8.2/MoinMoin/Page.py	2009-04-26 16:43:48.000000000 -0400
   3 @@ -598,7 +598,16 @@
   4          @rtype: bool
   5          @return: true, if this page is writable or does not exist
   6          """
   7 -        return os.access(self._text_filename(), os.W_OK) or not self.exists()
   8 +        result = True
   9 +        if self.exists():
  10 +            try:
  11 +                # Attempt to append nothing fecklessly
  12 +                open(self._text_filename(), 'a').close()
  13 +            except IOError:
  14 +                # Failed open should return errno.EACCES
  15 +                # Any repeatable error will prevent edit/creation
  16 +                result = False
  17 +        return result
  18  
  19      def isUnderlayPage(self, includeDeleted=True):
  20          """ Does this page live in the underlay dir?

Page.py.patch

Include read-only dictionaries in those searched.

Toggle line numbers 
   1 --- moin-1.8.2/MoinMoin/action/SpellCheck.py	2009-01-06 19:26:50.000000000 -0500
   2 +++ moin-1.8.2/MoinMoin/action/SpellCheck.py	2009-04-22 00:49:12.000000000 -0400
   3 @@ -39,7 +39,7 @@
   4      # validate candidate list (leave out directories!)
   5      wordsfiles = []
   6      for f in candidates:
   7 -        if os.path.isfile(f) and os.access(f, os.F_OK | os.R_OK):
   8 +        if os.path.isfile(f):
   9              wordsfiles.append(f)
  10  
  11      # return validated file list

SpellCheck.py.patch

Don't fail to start just because pages directory is read-only.

Toggle line numbers 
   1 --- moin-1.8.2/MoinMoin/config/multiconfig.py	2009-01-23 23:39:19.000000000 -0500
   2 +++ moin-1.8.2/MoinMoin/config/multiconfig.py	2009-04-27 09:21:47.000000000 -0400
   3 @@ -535,7 +535,6 @@
   4          Both data and underlay should exists and allow read, write and
   5          execute.
   6          """
   7 -        mode = os.F_OK | os.R_OK | os.W_OK | os.X_OK
   8          for attr in ('data_dir', 'data_underlay_dir'):
   9              path = getattr(self, attr)
  10  
  11 @@ -544,7 +543,7 @@
  12                  continue
  13  
  14              path_pages = os.path.join(path, "pages")
  15 -            if not (os.path.isdir(path_pages) and os.access(path_pages, mode)):
  16 +            if not os.path.isdir(path_pages):
  17                  msg = """
  18  %(attr)s "%(path)s" does not exist, or has incorrect ownership or
  19  permissions.

multiconfig.py.patch

Discussion

Plan

CategoryMoinMoinPatch