1 files changed, 94 insertions, 0 deletions
diff --git a/tests/cp/existing-perm-race.sh b/tests/cp/existing-perm-race.sh
new file mode 100755
index 0000000..4b862ad
--- /dev/null
+++ b/tests/cp/existing-perm-race.sh
@@ -0,0 +1,94 @@
+#!/bin/sh
+# Make sure cp -p isn't too generous with existing file permissions.
+
+# Copyright (C) 2006-2020 Free Software Foundation, Inc.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
+print_ver_ cp
+
+require_membership_in_two_groups_
+
+# cp -p gives ENOTSUP on NFS on Linux 2.6.9 at least
+require_local_dir_
+
+require_no_default_acl_ .
+
+set _ $groups; shift
+g1=$1
+g2=$2
+
+
+umask 077
+mkfifo_or_skip_ fifo
+
+touch fifo-copy &&
+chgrp $g1 fifo &&
+chgrp $g2 fifo-copy &&
+chmod g+r fifo-copy || framework-failure
+
+# Terminate any background cp process
+cleanup_() { kill $pid 2>/dev/null && wait $pid; }
+
+# Copy a fifo's contents.  That way, we can examine the
+# destination permissions before they're finalized.
+cp -p --copy-contents fifo fifo-copy & pid=$!
+
+(
+  # Now 'cp' is reading the fifo.  Wait for the destination file to
+  # be written to, encouraging things along by echoing to the fifo.
+  while test ! -s fifo-copy; do
+    echo foo
+  done
+
+  # Check the permissions of the destination.
+  ls -l -n fifo-copy >ls.out &&
+
+  # Close the fifo so that "cp" can continue.  But output first,
+  # before exiting, otherwise some shells would optimize away the file
+  # descriptor that holds the fifo open.
+  echo foo
+) >fifo || fail=1
+
+# Check that the destination mode is safe while the file is being copied.
+read mode links owner group etc <ls.out || fail=1
+case $mode in
+  -rw-------*) ;;
+
+  # FIXME: Remove the following case; the file mode should always be
+  # 600 while the data are being copied.  This will require changing
+  # cp so that it also does not put $g1's data in a file that is
+  # accessible to $g2.  This fix will not close a security hole, since
+  # a $g2 process can maintain an open file descriptor to the
+  # destination, but it's safer anyway.
+  -rw-r-----*)
+    # If the file has group $g1 and is group-readable, that is definitely bogus,
+    # as neither the source nor the destination was readable to group $g1.
+    test "$group" = "$g1" && fail=1;;
+
+  *) fail=1;;
+esac
+
+wait $pid || fail=1
+
+# Check that the final mode and group are right.
+ls -l -n fifo-copy >ls.out &&
+read mode links owner group etc <ls.out || fail=1
+case $mode in
+  -rw-------*) test "$group" = "$g1" || fail=1;;
+  *) fail=1;;
+esac
+
+Exit $fail