Re: new module write-any-file

[Bruno Haible]

Hello Paul,

Please accept some nitpicking:
- The code uses the Solaris 10 APIs. How about also using the Linux API
  for "capabilities" - capget() - that was added in Linux 2.2 and glibc-2.1.x?
- If priv_allocset fails, the function returns false without considering
  geteuid (). And if priv_allocset succeeds, it will not cache the result,
  but instead redo the same system calls next time. Is this intentional?
- If getppriv fails, the function also returns false without considering
  geteuid ().

Here's a tentative patch to address the last two problems.

*** lib/write-any-file.c        23 Mar 2007 17:33:07 -0000      1.1
--- lib/write-any-file.c        23 Mar 2007 23:32:51 -0000
***************
*** 42,53 ****
        priv_set_t *pset = priv_allocset ();
        if (pset)
        {
!         can =
!           (getppriv (PRIV_EFFECTIVE, pset) == 0
!            && priv_ismember (pset, PRIV_FILE_DAC_WRITE));
          priv_freeset (pset);
        }
        else
  #else
        /* In traditional Unix, only root can unlink directories.  */
        can = (geteuid () == 0);
--- 42,55 ----
        priv_set_t *pset = priv_allocset ();
        if (pset)
        {
!         if (getppriv (PRIV_EFFECTIVE, pset) == 0)
!           can = priv_ismember (pset, PRIV_FILE_DAC_WRITE);
!         else
!           can = (geteuid () == 0);
          priv_freeset (pset);
        }
        else
+       can = (geteuid () == 0);
  #else
        /* In traditional Unix, only root can unlink directories.  */
        can = (geteuid () == 0);