tests/cp/existing-perm-race

   1 #!/bin/sh
   2 # Make sure cp -p isn't too generous with existing file permissions.
   3
   4 # Copyright (C) 2006-2011 Free Software Foundation, Inc.
   5
   6 # This program is free software: you can redistribute it and/or modify
   7 # it under the terms of the GNU General Public License as published by
   8 # the Free Software Foundation, either version 3 of the License, or
   9 # (at your option) any later version.
  10
  11 # This program is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 # GNU General Public License for more details.
  15
  16 # You should have received a copy of the GNU General Public License
  17 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18
  19 . "${srcdir=.}/init.sh"; path_prepend_ ../src
  20 print_ver_ cp
  21
  22 require_membership_in_two_groups_
  23
  24 # cp -p gives ENOTSUP on NFS on Linux 2.6.9 at least
  25 require_local_dir_
  26
  27 set _ $groups; shift
  28 g1=$1
  29 g2=$2
  30
  31
  32 umask 077
  33 mkfifo_or_skip_ fifo
  34
  35 touch fifo-copy &&
  36 chgrp $g1 fifo &&
  37 chgrp $g2 fifo-copy &&
  38 chmod g+r fifo-copy || framework-failure
  39
  40 # Copy a fifo's contents.  That way, we can examine the
  41 # destination permissions before they're finalized.
  42 cp -p --copy-contents fifo fifo-copy &
  43 cp_pid=$!
  44
  45 (
  46   # Now 'cp' is reading the fifo.  Wait for the destination file to
  47   # be written to, encouraging things along by echoing to the fifo.
  48   while test ! -s fifo-copy; do
  49     echo foo
  50   done
  51
  52   # Check the permissions of the destination.
  53   ls -l -n fifo-copy >ls.out &&
  54
  55   # Close the fifo so that "cp" can continue.  But output first,
  56   # before exiting, otherwise some shells would optimize away the file
  57   # descriptor that holds the fifo open.
  58   echo foo
  59 ) >fifo || fail=1
  60
  61 # Check that the destination mode is safe while the file is being copied.
  62 read mode links owner group etc <ls.out || fail=1
  63 case $mode in
  64   -rw-------*) ;;
  65
  66   # FIXME: Remove the following case; the file mode should always be
  67   # 600 while the data are being copied.  This will require changing
  68   # cp so that it also does not put $g1's data in a file that is
  69   # accessible to $g2.  This fix will not close a security hole, since
  70   # a $g2 process can maintain an open file descriptor to the
  71   # destination, but it's safer anyway.
  72   -rw-r-----*)
  73     # If the file has group $g1 and is group-readable, that is definitely bogus,
  74     # as neither the source nor the destination was readable to group $g1.
  75     test "$group" = "$g1" && fail=1;;
  76
  77   *) fail=1;;
  78 esac
  79
  80 wait $cp_pid || fail=1
  81
  82 # Check that the final mode and group are right.
  83 ls -l -n fifo-copy >ls.out &&
  84 read mode links owner group etc <ls.out || fail=1
  85 case $mode in
  86   -rw-------*) test "$group" = "$g1" || fail=1;;
  87   *) fail=1;;
  88 esac
  89
  90 Exit $fail