196 lines
7.0 KiB
Markdown
196 lines
7.0 KiB
Markdown
# backup.sh 
|
|
`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 environments such as VPS, personal servers and
|
|
workstations. `backup.sh` uses [rsync](https://linux.die.net/man/1/rsync), [tar](https://linux.die.net/man/1/tar)
|
|
and [gpg](https://linux.die.net/man/1/gpg) to copy, compress and encrypt the backup.
|
|
|
|
`backup.sh` works under the following operating systems:
|
|
- GNU/Linux;
|
|
- OpenBSD
|
|
- FreeBSD;
|
|
- Apple MacOS.
|
|
|
|
## Installation
|
|
`backup.sh` consists in a single source file, to install it you can copy the script wherever you want.
|
|
Alternatively, you can install the script, the default sources file and the man file using the following command:
|
|
```sh
|
|
$> sudo make install
|
|
```
|
|
This will copy `backup.sh` into `/usr/local/bin/backup.sh`, `sources.bk` into `/usr/local/etc/sources.bk` and
|
|
`backup.sh.1` into `/usr/share/man/man1/backup.sh.1`. To uninstall the program along with the sample _sources file_ and the manual page,
|
|
you can issue `sudo make uninstall`.
|
|
|
|
At this point you still need to install the following dependencies:
|
|
- `rsync`
|
|
- `tar`
|
|
- `gpg`
|
|
|
|
## Usage
|
|
To show the available options, you can run `backup.sh --help`, which will print out the following message:
|
|
```text
|
|
backup.sh - POSIX compliant, modular and lightweight backup utility.
|
|
|
|
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.
|
|
```
|
|
|
|
As you can see, `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:
|
|
|
|
```text
|
|
<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_:
|
|
|
|
```text
|
|
nginx=/etc/nginx/
|
|
ssh=/etc/ssh/
|
|
```
|
|
|
|
`backup.sh` will create two folders inside the backup archive with the following syntax:
|
|
```text
|
|
backup-<LABEL>-<YYYYMMDD>
|
|
```
|
|
|
|
In the previous example, this would be:
|
|
```text
|
|
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 `sources.bk`(or at `/usr/local/etc/sources.bk`).
|
|
|
|
After having defined the _sources file_, you can invoke `backup.sh` using the following syntax:
|
|
```sh
|
|
$> 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:
|
|
```sh
|
|
$> sudo ./backup.sh --backup sources.bk /home/john badpw1234
|
|
```
|
|
|
|
The backup utility will begin to copy the files defined in the _sources file_:
|
|
```text
|
|
Copying nginx(1/2)
|
|
Copying ssh(2/2)
|
|
Compressing backup...
|
|
Encrypting backup...
|
|
File name: /home/marco/backup-<HOSTNAME>-<YYYYMMDD>.tar.gz.enc
|
|
File size: 7336400696(6.9G)
|
|
File hash: 0e75ca393117f389d9e8edfea7106d98
|
|
Elapsed time: 259 seconds.
|
|
```
|
|
|
|
After that, you will find the final backup archive in `/home/john/backup-<HOSTNAME>-<YYYYMMDD>.tar.gz.enc`.
|
|
|
|
You can also use `backup.sh` from a crontab rule:
|
|
```sh
|
|
$> sudo crontab -e
|
|
30 03 * * 6 EKEY=$(cat /home/john/.ekey) bash -c '/usr/local/bin/backup.sh -b /usr/local/etc/sources.bk /home/john $EKEY' > /dev/null 2>&1
|
|
|
|
```
|
|
|
|
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:
|
|
|
|
```sh
|
|
$> ./backup.sh --extract <ENCRYPTED_ARCHIVE> <ARCHIVE_PASSWORD>
|
|
```
|
|
|
|
Where `<ENCRYPTED_ARCHIVE>` is the encrypted backup and `<ARCHIVE_PASSWORD>` is the backup password.
|
|
|
|
For instance:
|
|
|
|
```sh
|
|
$> ./backup.sh --extract backup-<hostname>-<YYYYMMDD>.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:
|
|
```text
|
|
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 _gpg_ 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 encrypted using gpg. By default, it is used with the following parameters:
|
|
|
|
|
|
```
|
|
$> gpg -a \
|
|
--symmetric \
|
|
--cipher-algo=AES256 \
|
|
--no-symkey-cache \
|
|
--pinentry-mode=loopback \
|
|
--batch --passphrase-fd 3 3<<< "$PASSWORD" \
|
|
--output "$OUTPUT" \
|
|
"$INPUT"
|
|
```
|
|
|
|
This command encrypts the backup using the AES-256 symmetric encryption algorithm with a 256bit key. Here is what each flag do:
|
|
- `--symmetric`: Use symmetric encryption;
|
|
- `--cipher-algo=AES256`: Use AES256 algorithm;
|
|
- `--no-symkey-cache`: Do not save password on GPG's cache;
|
|
- `--pinentry-mode=loopback --batch`: Do not prompt the user;
|
|
- `--passphrase-fd 3 3<< "$PASSWORD"`: Read password without revealing it on `ps`;
|
|
- `--output`: Specify output file;
|
|
- `$INPUT`: Specify input file.
|
|
|
|
## Unit tests
|
|
`backup.sh` provides some unit tests inside the `tests.sh` script. This script generates some dummy files inside the following
|
|
directories:
|
|
- /var/log
|
|
- /var/www
|
|
- /etc/nginx
|
|
- /etc/ssh
|
|
|
|
For this reason, this script should **NOT** be used in non-testing environments. To run all tests, issue the following command:
|
|
```sh
|
|
$> sudo ./tests.sh I_HAVE_READ_THE_HELPER
|
|
```
|
|
|
|
## License
|
|
This software is released under GPLv3, you can obtain a copy of this license by cloning this repository or by visiting
|
|
[this page](https://choosealicense.com/licenses/gpl-3.0/).
|