chmod octal form of sgid/suid removal fails

[Jan Engelhardt]

Cc'ed bug-coreutils.
The following bug affects at least:
 coreutils 6.4 (used in opensuse 10.2 - open a bug report here)
 coreutils 6.9

On May 12 2007 15:16, J G Miller wrote:                                         
>From: J G Miller
>To: Jan Engelhardt
>Subject: re: chmod octal form of sgid/suid removal fails
>
>[...]

Ah yes you are right.

$ mkdir /dev/shm/me
$ strace -e chmod chmod 0755 me
chmod("me", 02755)                      = 0

This seems to be a bug in mode_compile() which does not
care about leading zeros, CONTRATY to what the manpage says:

  A numeric mode is from one to  four  octal  digits  (0-7),  derived  by
  adding up the bits with values 4, 2, and 1.  Omitted digits are assumed
  to be leading zeros, except that if  the  first  digit  is  omitted,  a
  directory's  set  user  and  group ID bits are not affected.

and at the same time, the mode_adjust() function just goes
by "directory or not" (line 323) and does not really care
about the leading zero either.

323    mode_t omit_change =
324     (dir ? S_ISUID | S_ISGID : 0) & ~ changes->mentioned;

which is always 06000 for directories - which should not be.



        Jan
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