Securing /tmp in linux

Securing /tmp is an important part in linux system. I am quoting the general way to secure /tmp in case it is not mounted as a separate partition:

1. Create a file inside /dev with the required size using dd command. Here I am using 500MB.

cd /dev
dd if=/dev/zero of=tmpDSK bs=1024 count=500000

2. Format it with the required filesystem.

mkfs.ext3 /dev/tmpDSK

3. If you need to backup current /tmp dir, do it using cp -rp command. After that mount the newly created file /dev/tmpDSK on /tmp.

mount -o loop,noexec,nosuid,rw /dev/tmpDSK /tmp

4. Give sticky bit and full permission to /tmp.

chmod 1777 /tmp

5. Create entries in /etc/fstab for mounting /tmp during boot process.

vim /etc/fstab

/dev/tmpDSK /tmp ext3 loop,noexec,nosuid,rw 0 0

Save the file.

That is it. You have now got a secured /tmp directory!