Bug in sed

[Rasmus Olsen]

I have found that sed does not respect the write file permissions. It is
possible to change any file with sed -i as long as the user has write
permission to the directory and read permission to the file.

sed versions:

GNU sed version 4.1.5
Copyright (C) 2003 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE,
to the extent permitted by law.

GNU sed version 4.2.1
Copyright (C) 2009 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE,
to the extent permitted by law.



Steps to reproduce the bug.

echo "hello world" > file
chmod a=r file
sed -i s/hello/my/ file

Best Regards

Rasmus