b2rsum is a Bash script to compute and check BLAKE2 message digest recursively. It's a b2sum wrapper that adds the capability of processing an entire directory.
It accepts all of b2sum options plus new ones. Files generated with it are 100% compatible with b2sum and vice versa. See more at the examples.
This is free (as in freedom and beer) software under GNU GPL v3.0+.
These come by default in most modern distros.
Clone this repository or download a release, then run make install as privileged user (probably sudo make install).
You can optionally do make lint && make test to check for errors (it requires shellcheck for linting), specially if you are cloning the repository.
Tests can also be run individually with make tests/tXXXX-description.sh and debugged with ./tests/tXXXX-description.sh -v. Sharness is used as framework.
Store the checksums of every file in the current directory, copy every file to a backup destination then check if the copy succeeded.
hackan@dev:/var/lib/mongodb$ b2rsum -o
b2rsum v0.1.2 Copyright (C) 2017 HacKan (https://hackan.net)
Saving results in BLAKE2SUMS
hackan@dev:/var/lib/mongodb$ rsync -raP . /mnt/backup/
sending incremental file list
...
hackan@dev:/var/lib/mongodb$ cd /mnt/backup/
hackan@dev:/mnt/backup/$ b2rsum -oRESULTS -wc BLAKE2SUMS && echo "ALL FILES OK" || echo "SOME FILE FAILED!"
b2rsum v0.1.2 Copyright (C) 2017 HacKan (https://hackan.net)
Saving results in RESULTS
ALL FILES OK
In this example, the BLAKE2SUMS file was copied the same way as the rest of the files, so in case of a transfer failure, the posibility of ending with a corrupted file exists. Maybe using other transfer method would be preferred, or calculating the BLAKE2 of that file, or even signing the file with GPG.
The last line sums it all up: -o stores the results in the given file RESULTS so it can be analized later; -wc executes the checking, reading from BLAKE2SUMS file, and throws warning about improperly formatted checksum lines (helps detecting corruption of itself, but previously mentioned methods are better). Finally, a simple echo is used for better visual feedback.
Github can generate a release from a tag, like the ones here. When you create a release, Github grabs every file in the repository and creates two packages: a zip and a tar.gz. However, even though tags can be signed, those automatically generated packages can not! An advance user can git clone the repository, then git verify-tag the tag, to finally git checkout that tag; but a non-git user (most users) rely on those releases. So, there's a real need to also sign those packages!.
Another option is to omit the usage of those packages but there'll be always a distracted user that might use them, so the following aproach is better.
What to do then? Verify those packages, sign them and upload the signatures to the release (releases can be easily edited to uplad files). The process of verifying those packages consist in two main steps: check that files from the local repo hasn't been modified in the package, and check that there are no extraneous foreign files.
- Use b2rsum to create a hash file of the local repo, download packages from the release and check the files in there:
hackan@dev:~/workspace/my-repo$ b2rsum -o
b2rsum v0.1.2 Copyright (C) 2017 HacKan (https://hackan.net)
Saving results in BLAKE2SUMS
hackan@dev:~/workspace/my-repo$ cd /tmp
hackan@dev:/tmp$ wget https://github.com/my-username/my-repo/archive/tag-name.tar.gz
hackan@dev:/tmp$ tar -xf tag-name.tar.gz
hackan@dev:/tmp$ cd tag-name
hackan@dev:/tmp/tag-name$ cp ~/workspace/my-repo/BLAKE2SUMS ./
hackan@dev:/tmp/tag-name$ b2rsum -oRESULTS -c --ignore-missing BLAKE2SUMS && echo "ALL OK" || echo "WOW! Something fishy's going on"
b2rsum v0.1.2 Copyright (C) 2017 HacKan (https://hackan.net)
Saving results in RESULTS
ALL OK
Since b2rsum will hash every file in the local repo, which include dot files and dirs, like .git dir, that are not included in the packages (obviously), --ignore-missing is necessary or warnings will be raised. Once again echo is used for quick visual feedback, but checking the RESULT file is convenient.
- Use b2rsum to create a hash file from the package and compare it with the local repo, to ensure there're no foreign files:
hackan@dev:/tmp/tag-name$ b2rsum -o
b2rsum v0.1.2 Copyright (C) 2017 HacKan (https://hackan.net)
Saving results in BLAKE2SUMS
hackan@dev:/tmp/tag-name$ cd ~/workspace/my-repo
hackan@dev:~/workspace/my-repo$ cp /tmp/tag-name/BLAKE2SUMS ./
hackan@dev:~/workspace/my-repo$ b2rsum -oRESULTS -c BLAKE2SUMS && echo "ALL OK" || echo "WOW! Something fishy's going on"
b2rsum v0.1.2 Copyright (C) 2017 HacKan (https://hackan.net)
Saving results in RESULTS
ALL OK
Now, we are interested in any file that is missing, or left, so full check with b2rsum. If everything goes ok, now the package can be signed:
hackan@dev:/tmp$ gpg --sign tag-name.tar.gz
The same operation must be done for the zip package, and that's it! Upload signature files to Github. Trully verified releases :)
By default, if no parameters are passed, or a dot is used, the current directory is checked. Dot files are always included in the check!
hackan@dev:/tmp/b2sum$ b2rsum
b2rsum v0.1.0 Copyright (C) 2017 HacKan (https://hackan.net)
87b95c42320170686763b1d06b925df113edbeb2303ec14005cf57b7fa50bd694ed35907d45cd622848d15bf2ec1c2cd48d084199ea32e44625b0465c2837a02 /tmp/b2sum/test4
f3d464f5ce9592d6042e9c56b11db79d62c11bac46e988ebb678129fc8488eedbbd04aa9038308806489964416597d6ad723a9dacfd143bdd58059cf93c79f35 /tmp/b2sum/test5
Several files or directories can be specified
hackan@dev:~$ b2rsum /tmp/b2sum /tmp/b2sum-2
b2rsum v0.1.0 Copyright (C) 2017 HacKan (https://hackan.net)
bb66fc7524a77ea47fd949f4472f21e1ba87b2a77ffe5fd1c57c5c856f8e2f7f4711e816a00101b23740771dc3d19960c7e2376ca816b32ef708ea45eb69103e /tmp/b2sum/test2
aea384705e52359b3f4ff4b4f0122b7afa2f7fb5f186d21770c2460ca199710d55e926fb5dd1813baf8725d5e71d15ec35f036781248c358b229eebefcce64d3 /tmp/b2sum/test1
fbab3b736a159baa0c6db12fe95928a7025312ce734ee451272e8b0ea738e5a777cf9e61d93f14fcfefd3f1719f4c4993e8bd9a56a9d405fc83540d8f8f806a2 /tmp/b2sum-2/test1
It accepts globs too, and the output can be pipped or redirected easily since the version header is in stderr:
hackan@dev:~$ b2rsum /tmp/b2sum* > BLAKE2SUMS
b2rsum v0.1.0 Copyright (C) 2017 HacKan (https://hackan.net)
hackan@dev:~$ cat BLAKE2SUMS
bb66fc7524a77ea47fd949f4472f21e1ba87b2a77ffe5fd1c57c5c856f8e2f7f4711e816a00101b23740771dc3d19960c7e2376ca816b32ef708ea45eb69103e /tmp/b2sum/test2
aea384705e52359b3f4ff4b4f0122b7afa2f7fb5f186d21770c2460ca199710d55e926fb5dd1813baf8725d5e71d15ec35f036781248c358b229eebefcce64d3 /tmp/b2sum/test1
fbab3b736a159baa0c6db12fe95928a7025312ce734ee451272e8b0ea738e5a777cf9e61d93f14fcfefd3f1719f4c4993e8bd9a56a9d405fc83540d8f8f806a2 /tmp/b2sum-2/test1
The output can be silenced with --quiet (it shows only errors and warnings) or --status (it shows no messages at all). Of course, when in creation mode, checksums are always displayed. Those options have no effect regarding displaying of checksums.
Using --output, or the short -o, the output is redirected to a file named BLAKE2SUMS as in the example above (note that the destination file is overwritten w/o question):
hackan@dev:~$ b2rsum --quiet --output /tmp/b2sum*
hackan@dev:~$ cat BLAKE2SUMS
bb66fc7524a77ea47fd949f4472f21e1ba87b2a77ffe5fd1c57c5c856f8e2f7f4711e816a00101b23740771dc3d19960c7e2376ca816b32ef708ea45eb69103e /tmp/b2sum/test2
aea384705e52359b3f4ff4b4f0122b7afa2f7fb5f186d21770c2460ca199710d55e926fb5dd1813baf8725d5e71d15ec35f036781248c358b229eebefcce64d3 /tmp/b2sum/test1
fbab3b736a159baa0c6db12fe95928a7025312ce734ee451272e8b0ea738e5a777cf9e61d93f14fcfefd3f1719f4c4993e8bd9a56a9d405fc83540d8f8f806a2 /tmp/b2sum-2/test1
During a check routine (--check), those options causes the output to be silenced, thus appending the --output option will result in an empty file.
To use a file different than BLAKE2SUMS as output, use --output=FILE or the short version -oFILE. Using spaces isn't allowed (it's a getopt limitation).
Check the man page (man b2rsum) or the help (b2rsum --help) for more options.
b2rsum v0.1.2 Copyright (C) 2017 HacKan (https://hackan.net)
Usage: b2rsum [OPTION]... [FILE or DIRECTORY]...
Print or check BLAKE2 (512-bit) checksums recursively.
If no FILE or DIRECTORY is indicated, or it's a dot (.), then the current
directory is processed.
The default mode is to compute checksums. Check mode is indicated with --check.
Options:
-c, --check read BLAKE2 sums from the FILEs and check them
-o[FILE], --output[=FILE] output to FILE instead of standard output, or a
file named BLAKE2SUMS in the current
directory if FILE is not specified
-q, --quiet quiet mode: don't print messages, only hashes;
during check mode, don't print OK for each
successfully verified file
-s, --status very quiet mode: output only hashes, no messages;
status code shows success
--license show license and exit
--version show version information and exit
-h, --help show this text and exit
The following four options are useful only when computing checksums:
-t, --text read in text mode (default)
-b, --binary read in binary mode
--tag create a BSD-style checksum
-l, --length digest length in bits; must not exceed the maximum
for the blake2 algorithm and must be a multiple
of 8
The following three options are useful only when verifying checksums:
--ignore-missing don't fail or report status for missing files
--strict exit non-zero for improperly formatted checksum lines
-w, --warn warn about improperly formatted checksum lines
Sums are made using 'b2sum'. Full documentation at:
<http://www.gnu.org/software/coreutils/b2sum>.
The sums are computed as described in RFC 7693. When checking, the input
should be a former output of this program. The default mode is to print a
line with checksum, a space, a character indicating input mode ('*' for binary,
' ' for text or where binary is insignificant), and name for each FILE.
This program comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to redistribute it under certain
conditions; type 'b2rsum --license' for details.
More information may be found in the b2rsum(1) man page.
b2rsum is made by HacKan under GNU GPL v3.0+. Forks, Issues, PRs, etc, are all welcome.
Copyright (C) 2017 HacKan (https://hackan.net)
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.