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) 2006-2010 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 if test "$VERBOSE" = yes; then
  20   set -x
  21   cp --version
  22 fi
  23
  24 . $srcdir/test-lib.sh
  25
  26 require_membership_in_two_groups_
  27
  28 # cp -p gives ENOTSUP on NFS on Linux 2.6.9 at least
  29 require_local_dir_
  30
  31 set _ $groups; shift
  32 g1=$1
  33 g2=$2
  34
  35
  36 umask 077
  37 mkfifo fifo ||
  38   skip_test_ "fifos not supported"
  39
  40 touch fifo-copy &&
  41 chgrp $g1 fifo &&
  42 chgrp $g2 fifo-copy &&
  43 chmod g+r fifo-copy || framework-failure
  44
  45 # Copy a fifo's contents.  That way, we can examine the
  46 # destination permissions before they're finalized.
  47 cp -p --copy-contents fifo fifo-copy &
  48 cp_pid=$!
  49
  50 (
  51   # Now 'cp' is reading the fifo.  Wait for the destination file to
  52   # be written to, encouraging things along by echoing to the fifo.
  53   while test ! -s fifo-copy; do
  54     echo foo
  55   done
  56
  57   # Check the permissions of the destination.
  58   ls -l -n fifo-copy >ls.out &&
  59
  60   # Close the fifo so that "cp" can continue.  But output first,
  61   # before exiting, otherwise some shells would optimize away the file
  62   # descriptor that holds the fifo open.
  63   echo foo
  64 ) >fifo || fail=1
  65
  66 # Check that the destination mode is safe while the file is being copied.
  67 read mode links owner group etc <ls.out || fail=1
  68 case $mode in
  69   -rw-------*) ;;
  70
  71   # FIXME: Remove the following case; the file mode should always be
  72   # 600 while the data are being copied.  This will require changing
  73   # cp so that it also does not put $g1's data in a file that is
  74   # accessible to $g2.  This fix will not close a security hole, since
  75   # a $g2 process can maintain an open file descriptor to the
  76   # destination, but it's safer anyway.
  77   -rw-r-----*)
  78     # If the file has group $g1 and is group-readable, that is definitely
  79     # bogus, as neither the source nor the destination was readable to group $g1.
  80     test "$group" = "$g1" && fail=1;;
  81
  82   *) fail=1;;
  83 esac
  84
  85 wait $cp_pid || fail=1
  86
  87 # Check that the final mode and group are right.
  88 ls -l -n fifo-copy >ls.out &&
  89 read mode links owner group etc <ls.out || fail=1
  90 case $mode in
  91   -rw-------*) test "$group" = "$g1" || fail=1;;
  92   *) fail=1;;
  93 esac
  94
  95 Exit $fail