merge disaster recovery into markdown

disaster/index.md

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+# Disaster Recovery

disaster/linux.md

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+## Linux
+
+Here are some of the worst things that they can do, and how to hopefully recover.
+
+
+### Invalid Password
+
+The red team has changed the password to the root account.
+
+1. Reboot and hold shift
+2. Press 'e' at the grub prompt to edit the kernel command line
+3. Add the option `init=/bin/bash` to the line that says linux
+4. Mount the root filesystem, `mount -o remout,rw /`
+5. Use 'vi' to edit the `/etc/passwd` file and remove the 'x' between the 2nd and 3rd colon on the root user
+6. Write the file
+7. Use 'passwd' to create a new root password
+7. Reboot
+
+
+### Chmod Not Executable
+
+While this initially might not seem like it is too bad, there is a problem where bash does not provide a built-in to fix this. This can be particularly devious if the entire root directory is marked not executable. If the entire file system is not executable, you are looking at a live CD or a slave mounted drive.
+
+There are a few options here roughly sorted by time to fix:
+
+* Use a programming language like python, perl, or C to write your own chmod command to fix chmod
+* Use the linker directly by running `/lib/ld-*.so /bin/chmod 755 /bin/chmod` as root
+* Use a shell like busybox, zsh, or ksh that provides a built-in chmod
+* Reinstall chmod from repos or a working machine
+* Dump the bits of the binary and manually edit the permission bits
+* Use a live CD
+* Power off the machine, remove the hard drive, slave mount it to a different machine that has a working chroot, mount the drive, and fix it
+
+
+#### Chmod Examples
+
+
+##### C
+
+```c
+#include<sys/stat.h>
+
+int main(int argc, char *argv[]) {
+	chmod("/bin/chmod", S_IRWXU);
+	return 0;
+}
+```
+
+
+##### Perl
+
+```sh
+#!/bin/sh
+perl -e 'chmod 0755, "/bin", "/bin/chmod"'
+```
+
+
+##### Python
+
+```python
+import os
+os.chmod('/bin/chmod', 0755)
+```