207 lines
6.9 KiB
Markdown
207 lines
6.9 KiB
Markdown
---
|
|
title: backup.sh
|
|
section: 1
|
|
header: General Commands Manual
|
|
footer: Marco Cetica
|
|
date: March 14, 2023
|
|
---
|
|
|
|
# NAME
|
|
**backup.sh** is a POSIX compliant, modular and lightweight backup utility to save and encrypt your files.
|
|
|
|
# SYNOPSIS
|
|
```
|
|
Syntax: backup.sh [-b|-e|-h]
|
|
options:
|
|
-b|--backup SOURCES DEST PASS Backup folders from SOURCES file.
|
|
-e|--extract ARCHIVE PASS Extract ARCHIVE using PASS.
|
|
-h|--help Show this helper.
|
|
```
|
|
|
|
# DESCRIPTION
|
|
**backup.sh** is a POSIX compliant, modular and lightweight backup utility to save and encrypt your files.
|
|
This tool is intended to be used on small scale UNIX environment such as VPS, small servers and workstations.
|
|
**backup.sh** uses _rsync_, _tar_ and _openssl_ to copy, compress and encrypt the backup.
|
|
|
|
# OPTIONS
|
|
**backup.sh** supports two options: _backup creation_ and _backup extraction_.
|
|
The former requires root permissions, while the latter does not. Let us see them in details:
|
|
|
|
## Backup creation
|
|
To specify the directories to backup, **backup.sh** uses an associative array defined in a text file(called sources file)
|
|
with the following syntax:
|
|
|
|
```
|
|
<LABEL>=<PATH>
|
|
```
|
|
|
|
Where `<LABEL>` is the name of the backup and `<PATH>` is its path.
|
|
For example, if you want to back up _/etc/nginx_ and _/etc/ssh_, add the following entries to the sources file:
|
|
|
|
```
|
|
nginx=/etc/nginx/
|
|
ssh=/etc/ssh/
|
|
```
|
|
|
|
**backup.sh** will create two folders inside the backup archive with the following syntax:
|
|
|
|
```
|
|
backup-<LABEL>-<YYYYMMDD>
|
|
```
|
|
|
|
In the previous example, this would be:
|
|
|
|
```
|
|
backup-nginx-<YYYYMMDD>
|
|
backup-ssh-<YYYYMMDD>
|
|
```
|
|
|
|
You can add as many entries as you want, just be sure to use the proper syntax.
|
|
In particular, the sources file, _should not_ includes:
|
|
|
|
- Spaces between the label and the equal sign;
|
|
- Empty lines;
|
|
- Comments.
|
|
|
|
You can find a sample sources file at `backup_sources.bk`(or at `/usr/local/etc/backup_sources.bk`).
|
|
|
|
After having defined the sources file, you can invoke **backup.sh** using the following syntax:
|
|
```
|
|
$> sudo ./backup.sh --backup <SOURCES_FILE> <DEST> <ENCRYPTION_PASSWORD>
|
|
```
|
|
|
|
Where `<SOURCES_FILE>` is the _sources file_, `<DEST>` is the absolute path of the output of the backup _without trailing slashes_
|
|
and `<ENCRYPTION_PASSWORD>` is the password to encrypt the compressed archive.
|
|
|
|
In the previous example, this would be:
|
|
|
|
```
|
|
$> sudo ./backup.sh --backup sources.bk /home/john badpw1234
|
|
```
|
|
|
|
The backup utility will begin to copy the files defined in the sources file:
|
|
|
|
```
|
|
Copying nginx(1/2)
|
|
Copying ssh(2/2)
|
|
Compressing and encrypting backup...
|
|
Elapsed time: 10 seconds.
|
|
```
|
|
|
|
After that, you will find the final backup archive in `/home/john/backup-<HOSTNAME>-<YYYMMDD>.tar.gz.enc`.
|
|
|
|
You can also use **backup.sh** from a crontab rule:
|
|
|
|
```
|
|
$> sudo crontab -e
|
|
30 03 * * 6 EKEY=$(cat /home/john/.ekey) /usr/local/bin/backup.sh -b /usr/local/etc/sources.bk /home/john $EKEY
|
|
```
|
|
|
|
This will automatically run **backup.sh** every Saturday morning at 03:30 AM.
|
|
In the example above, the encryption key is stored in a local file(with fixed permissions) to avoid password leaking in crontab logs.
|
|
You can also adopt this practice while using the `--extract` option to avoid password leaking in shell history.
|
|
|
|
## Backup extraction
|
|
**backup.sh** can also extract the encrypted backup archive using the following syntax:
|
|
|
|
```
|
|
$> ./backup.sh --extract <ENCRYPTED_ARCHIVE> <ARCHIVE_PASSWORD>
|
|
```
|
|
|
|
Where `<ENCRYPTED_ARCHIVE>` is the encrypted backup and `<ARCHIVE_PASSWORD>` is the backup password.
|
|
|
|
For instance:
|
|
```
|
|
$> ./backup.sh --extract backup-<hostname>-<YYYMMDD>.tar.gz.enc badpw1234
|
|
```
|
|
|
|
This will create a new folder called `backup.sh.tmp` in your local directory.
|
|
Be sure to rename any directory with that name to avoid collisions. From the previous example, you should have the following directories:
|
|
|
|
```
|
|
backup-nginx-<YYYYMMDD>
|
|
backup-ssh-<YYYYMMDD>
|
|
```
|
|
|
|
## How does backup.sh work?
|
|
**backup.sh** uses _rsync_ to copy the files, _tar_ to compress the backup and _openssl_ to encrypt it.
|
|
By default, rsync is being used with the following parameters:
|
|
|
|
```
|
|
$> rsync -aPhrq --delete
|
|
```
|
|
|
|
That is:
|
|
|
|
- a: archive mode: rsync copies files recursively while preserving as much metadata as possible;
|
|
- P: progress/partial: allows rsync to resume interrupted transfers and to shows progress information;
|
|
- h: human readable output, rsync shows output numbers in a more readable way;
|
|
- r: recursive mode: forces rsync to copy directories and their content;
|
|
- q: quiet mode: reduces the amount of information rsync produces;
|
|
- delete: delete mode: forces rsync to delete any extraneous files at the destination dir.
|
|
|
|
|
|
After that the backup folder is being encrypred using openssl. By default, it is used with the following parameters:
|
|
|
|
|
|
```
|
|
$> openssl enc -aes-256-cbc -md sha512 -pbkdf2 -iter 100000 -salt -k "$PASSWORD" > file.tar.gz.enc
|
|
```
|
|
|
|
This command encrypts the backup using the AES-256-CBC symmetric encryption algorithm with a 256bit key. Here is what each option means:
|
|
|
|
- enc: encrypt mode: tell openssl to use encryption functionality;
|
|
- aes-256-cbc: encryption algorithm: this option tells openssl which encryption algorithm to use;
|
|
- md sh512: hashing algorithm: this option tells openssl which hashing algorithm to use for key derivation,
|
|
i.e., converting the text-based password(`$PASSWORD`) into an encryption key;
|
|
- pbkdf2: key deriving algorithm: this option tells openssl which key deriving algorithm to use. In this case
|
|
we use the _password-based key derivation function 2_ algorithm;
|
|
- iter 100000: number of iterations: this options tells openssl the number of iteration to use for the key derivation
|
|
function;
|
|
- salt: enable salting: this option tells openssl to add a random salt to the key derivation process in order to
|
|
avoid rainbow table based attacks.
|
|
|
|
# EXAMPLES
|
|
Below there are some examples that demostrate **backup.sh**'s usage.
|
|
|
|
1. Create a backup of `/etc/ssh`, `/var/www` and `/var/log` inside the `/tmp` directory using a password
|
|
stored in `/home/op1/.backup_pw`
|
|
|
|
The first thing to do is to define the source paths inside a _sources file_:
|
|
|
|
```
|
|
$> cat sources.bk
|
|
ssh=/etc/ssh
|
|
web_root=/var/www
|
|
logs=/var/log
|
|
```
|
|
|
|
After that we can load our encryption key from the specified file inside a environment variable:
|
|
|
|
```
|
|
$> ENC_KEY=$(cat /home/op1/.backup_pw)
|
|
```
|
|
|
|
Finally, we can start the backup process with:
|
|
|
|
```
|
|
$> sudo backup.sh --backup sources.bk /tmp $ENC_KEY
|
|
```
|
|
|
|
|
|
|
|
2. Extract the content of a backup made on 2023-03-14 with the password 'Ax98f!'
|
|
|
|
To do this, we can simply issue the following command:
|
|
|
|
```
|
|
$> backup.sh --extract backup-af9a8e6bfe15-20230314.tar.gz.enc "Ax98f!"
|
|
```
|
|
|
|
# AUTHORS
|
|
**backup.sh** was written by Marco Cetica on late 2018.
|
|
|
|
# BUGS
|
|
Submit bug reports online at: <email@marcocetica.com> or open an issue
|
|
on the issue tracker of the GitHub page of this project: https://github.com/ice-bit/backup.sh
|