Category Archives: unix

mFI mPower basic use without cloud and controller

After getting the mFI mPower unit, I saw that it really wasn’t planned for standalone use. I was also surprised at seeing no ethernet port; I’m not sure why I thought it’s going to have one.

This is a wifi IP power strip that seems to be designed neither fully for a consumer (why would a consumer need a IP power strip?) nor for an expert. After plugging it in and waiting for it to boot, you’re greeted with a new completely unprotected wifi network. After connecting to it, you’re hijacked in the same way captive portals technologies work. It seems pretty painless to configure a device to connect to a wifi network, and then either to cloud or to a local controller — a chunk of proprietary software that, based on the quick guide booklet, seems to be written in Java. Booklet mentions versions for Windows and OS X, but the website offers download for Linux as well.

I’m however uninterested in having a home machine run 24/7 and waste electricity just to occasionally control a power strip. I opted for the (for obvious reasons less secure) variant of going into the cloud. Unfortunately, the built-in web UI doesn’t give you an option to register nor a hint on doing so. Quick guide does mention the website, which reveals a login panel but no registration.

At least I could configure wifi connectivity without either controller software or cloud — but that seems to be all.

That’s because in October 2013 the service was shut down for new registrations, with promises of coming back. Seeing that was 10 months ago, I began to think I may have purchased a brick.

Luckily, apart from what’s served to the customer on the surface, the device seems to be rather open. I’m unfamiliar with how free and open source it is, but it seems to be built out of relatively understandable components. BusyBox is there, the usual UNIX-like directory structure is there. I also spotted dropbear, which means aside from a telnet daemon, it’s also providing an SSH service.

Default username and password set is ubnt/ubnt. Ouch. First obstacle: How do we change that?

We can use vi to edit /tmp/system.cfg. There it is! Username and password. But wait — what kind of a password hash is that?

Turns out it’s the output of crypt(3). This gets used to generate /etc/passwd.

PHP has the crypt() function as well. PHP’s numerous flaws are irrelevant for such simple use case, so we’ll be forgiven for using:

php <<< '<?php echo crypt("my_password", "SL");'

where “SL” is the salt. (In the stock password, it was “KQ”.)

You can add new users as well (although I’d highly advise changing at least the password of the default user), like so:

users.1.name=ubnt
users.1.password=KQiBBQ7dx8sx2
users.1.status=enabled
users.2.name=ivucica
users.2.password=AEPbWtbh7XaS.   
users.2.status=enabled

That’s really nice and flexible. But they could have either documented all this (and in an obvious place), or created a web UI (of course, while letting us deal directly through telnet and ssh, too).

To save these settings, punch in save. (Alternative command seems to be cfgmtd -f /tmp/system.cfg -w.) To give the system a chance to apply the settings, reboot.

While at it, you may want to disable the default unprotected wifi network, which for me was numbered 2:

wireless.2.status=disabled

What I also like in this device is that it seems to have the Linux-friendly Atheros chipset in it.

So next. How do we actually read stats or switch an outlet on or off?

cd /proc/power
# enable outlets we want to read stats from or that we want to control
for i in $(seq 1 3) ; do
  echo 1 > enabled${i}
done
# get current power usage
for i in $(seq 1 3) ; do
  echo "active_pwr$i: ${i}"
done
# turn off and on a slot
echo 0 > relay1
sleep 1
echo 1 > relay1

Other functionality is demonstrated and explained by forum member Sequim.

  • active_pwr – power factor corrected power demand
  • v_rms – RMS voltage – zero if outlet is off
  • i_rms – RMS current, as currently delivered
  • pf – power factor
  • energy_sum – totalized energy in Watt-hours delivered via this outlet, probably since last boot

And the /proc/led directory contains some nice controls for the LED.

Really lovely design. It’d have been even nicer if it had been properly documented and if it had a proper web UI shipped in case you don’t feel like dealing with all the power that these controls exposed as a filesystem provide.

Proxying Camlistore through nginx

I’ve went through this in order to secure access to Camlistore and delegate authorization to nginx. This doesn’t help, as I don’t yet have a securely stored password set up to protect it, but the first steps are there. Moving to something like LDAP-backed authorization for authentication on my machine and authentication of Camlistore is probably the way to go.

Without further ado, here is my partial nginx configuration, which should be useful if you already have a domain set up and you’d just like to direct toward Camlistore. I didn’t want to set up a subdomain, as I would have to get a new SSL certificate.

I’m bound to have made a mistake in configuration, so comments are welcome.

server {
        server_name ivan.vucica.net;
        access_log /var/log/nginx/ivan.vucica.net_access.log;
        error_log /var/log/nginx/ivan.vucica.net_error.log;
        root /somewhere/on/my/disk;
        listen 80;
        # skipped...

        location /camli {
                return 302 https://ivan.vucica.net:3180$request_uri;
        }
}
server {
        server_name ivan.vucica.net;
        access_log /var/log/nginx/ivan.vucica.net_access.log;
        error_log /var/log/nginx/ivan.vucica.net_error.log;
        root /somewhere/on/my/disk;
        listen 443 ssl;
        # skipped...

        location /camli {
                return 302 $scheme://ivan.vucica.net:3180$request_uri;
        }

        ssl_certificate /ssl/directory/on/my/disk/startssl-vucica.net.chained.crt;
        ssl_certificate_key /ssl/directory/on/my/disk/startssl-vucica.net.key;
        # ssl_protocols       SSLv3 TLSv1 TLSv1.1 TLSv1.2;
        # ssl_ciphers         HIGH:!aNULL:!MD5;

        # from: https://community.qualys.com/blogs/securitylabs/2013/08/05/configuring-apache-nginx-and-openssl-for-forward-secrecy#comment-3794
        ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
        ssl_prefer_server_ciphers on;
        ssl_ciphers "EECDH+ECDSA+AESGCM EECDH+aRSA+AESGCM EECDH+ECDSA+SHA384 EECDH+ECDSA+SHA256 EECDH+aRSA+SHA384 EECDH+aRSA+SHA256 EECDH+aRSA+RC4 EECDH EDH+aRSA RC4 !aNULL !eNULL !LOW !3DES !MD5 !EXP !PSK !SRP !DSS";

        # for ssl cache - see http://nginx.org/en/docs/http/configuring_https_servers.html 
        keepalive_timeout   70;
}
server {
        server_name ivan.vucica.net;
        access_log /var/log/nginx/ivan.vucica.net_camli_access.log;
        error_log /var/log/nginx/ivan.vucica.net_camli_error.log;
        root /somewhere/on/my/disk;
        listen 3180 ssl;

        location /camli {
                rewrite ^/camli/(.*) /$1 redirect;
                rewrite ^/camli$ / redirect;
        }
        location / {
                proxy_pass http://127.0.0.1:3179;
                proxy_connect_timeout 5;

                # not using after all, as it would need access to /etc/shadow.
                # see http://web.iti.upv.es/~sto/nginx/ngx_http_auth_pam_module-1.3/README.html
                # auth_pam "Secured Camli";
                # auth_pam_service_name "nginx";

                auth_basic "Secured Camli";
                auth_basic_user_file /path/to/ivucica-camli-user_file;
        }

        ssl_certificate /ssl/directory/on/my/disk/startssl-vucica.net.chained.crt;
        ssl_certificate_key /ssl/directory/on/my/disk/startssl-vucica.net.key;
        # ssl_protocols       SSLv3 TLSv1 TLSv1.1 TLSv1.2;
        # ssl_ciphers         HIGH:!aNULL:!MD5;

        # from: https://community.qualys.com/blogs/securitylabs/2013/08/05/configuring-apache-nginx-and-openssl-for-forward-secrecy#comment-3794
        ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
        ssl_prefer_server_ciphers on;
        ssl_ciphers "EECDH+ECDSA+AESGCM EECDH+aRSA+AESGCM EECDH+ECDSA+SHA384 EECDH+ECDSA+SHA256 EECDH+aRSA+SHA384 EECDH+aRSA+SHA256 EECDH+aRSA+RC4 EECDH EDH+aRSA RC4 !aNULL !eNULL !LOW !3DES !MD5 !EXP !PSK !SRP !DSS";

        # for ssl cache - see http://nginx.org/en/docs/http/configuring_https_servers.html 
        keepalive_timeout   70;
}

Camlistore itself is configured to listen only on 127.0.0.1. It doesn’t handle authentication, as using localhost authentication would require running nginx and camlistored under the same user. Adding a username+password authentication and using internal SSL would limit my long-term options for configuring authentication.

{
    "auth": "none",
    "listen": "localhost:3179",
    "identity": "AC5742DD",
    "identitySecretRing": "/path/to/camlistore/identity-secring.gpg",
    "blobPath": "/path/to/camlistore/blobs",
    "sqlite": "/path/to/camlistore/camli-index.db",
    "baseURL": "https://ivan.vucica.net:3180/",

    "shareHandler": true

}

To generate the .htpasswd file, refer to nginx documentation. Here follows an example; consider hard whether this is secure enough and appropriate for you.

printf "John:$(openssl passwd -crypt V3Ry)\n" >> .htpasswd # this example uses crypt encryption

Don’t forget that this will store the line in your .bash_history. (One way to avoid this specific issue is to prefix the command line with a space. Think hard whether this is enough for you.)

Mails appearing from d1stkfactory

If you have a Debian machine and emails appear to be coming from hostname @d1stkfactory, edit /etc/mailname and set this to your actual FQDN. Another instance where I found it locally is in /etc/exim4/update-exim4.conf.conf, which is almost certainly not read by my installation of Postfix (which does explicitly refer to /etc/mailname in one place).

This appeared on a machine running on DigitalOcean, so I presume “d” refers to DigitalOcean, and “factory” refers to their internal disk image building service. That’s just speculation though.

Ubuntu, touchscreen and dualscreen: HD Touchscreen on the left, laptop on the right

If you read about calibrating touchscreen with X11 and are capable of simple addition and division, you won’t have a problem building the transformation matrix and applying it. I won’t cover the same details on how to set the matrix using xinput set-prop since I just want to write down the resulting matrix and, perhaps, save people some time if they have a setup similar to mine.

To get the name of the device, open Terminal and punch in:

xinput

In the output I found that my “Acer T232HL”‘s input component is actually called “Advanced Silicon S.A CoolTouch(TM) System”. I can see all of its properties with:

xinput list-props Advanced Silicon S.A CoolTouch(TM) System

Since I’ve set up the screen to be on the left site, that means top-left corner of my touch area is simply offset by 0,0, and bottom-right is 1920,1080. Considering that the total width of the usable X area is 1920+1280, I get 1920/3600=0.6 as the c0 constant on the above link.

My usable area’s height is max(1080, 800) (the respective y component of the resolutions of the two displays). Considering that touch area’s height is also 1080, then the c2 component does not need to be scaled and should be exactly 1.

I also have absolutely no offsets, so c1 and c3 stay 0.

Result:

xinput set-prop "Advanced Silicon S.A CoolTouch(TM) System" --type=float "Coordinate Transformation Matrix" 0.6 0 0 0 1 0 0 0 1
# And if needed, to make the display configured as described above:
xrandr --output DP-0 --auto --left-of LVDS-0

From the times when I was trying to get Linux to run on iPaq H3800 devices using the kernel and distributions published at the now-defunct handhelds.org, I remember the “tslib” which included a touchscreen calibration tool. I wonder if that can and should be used to calibrate the modern multitouch displays.

Update (April 5th 2014): I just dug out package ‘xinput_calibrator’ by random googling, but have not tried it out yet.

A few notes on Camlistore

(Useful as of April 7 2014, git commit 6842063f7c1ff6ae47e302b50b6a5030867cc2cd)

I was playing a bit with Camlistore and I like what I see. The presentation of Camlistore on FOSDEM 2014 done by Brad Fitzpatrick is quite insightful.

Here’s just a few notes so I don’t forget the caveats etc. I didn’t use a completely clean machine, so these are not instructions completely vetted up for public consumption. I presume a Debian Wheezy machine. Leave comments below, or mail me at blogのvucica.net.

Installing Go

Camlistore depends on Go language, at least Go 1.1. To install on Debian, as of early 2014 you need to use testing or unstable distributions. Here’s my /etc/apt/sources.list:

deb http://ftp.nl.debian.org/debian wheezy main
deb http://security.debian.org/ wheezy/updates main

deb http://ftp.nl.debian.org/debian testing main
deb http://ftp.nl.debian.org/debian unstable main

Here’s my /etc/apt/preferences.d/prioritize-stable (I prefer to use stable):

Package: *
Pin: release a=stable
Pin-Priority: 950

Package: *
Pin: release a=testing
Pin-Priority: 900

Package: *
Pin: release a=unstable
Pin-Priority: 800

Then use aptitude to choose golang version from testing. Hit e to use automated conflict resolver. With r, mark unsatisfactory solutions, then use , and . to browse different resolutions. At some point you’ll be offered correct installation of dependencies for golang. Hit ! to apply, then hit g twice to install.

Installing Camlistore

Nearly straight from the website:

git clone https://camlistore.googlesource.com/camlistore
cd camlistore/
go run make.go

If instructed to install any packages, do so. I know I was requested to install sqlite3 libraries.

Start camlistored:

./bin/camlistored

You’ll automatically get default config placed at ${HOME}/.config/camlistore/server-config.json and secret keyring at ${HOME}/.config/camlistore/identity-secring.gpg.

Interesting locations

  • ${HOME}/camlistore – you installed Camlistore here
  • ${HOME}/.config/camlistore – configuration files
  • ${HOME}/var/camlistore – blobstore

Preparing clients

Again taken from GettingStarted document and modified.

Upon startup, camlistored should have output the GPG key to use in the command below. For me, it was third line:

2014/03/04 23:26:24 Generated new identity with keyId "F300546B" in file /home/ivucica/.config/camlistore/identity-secring.gpg

Use this here:

./bin/camput init --gpgkey ${REPLACE_WITH_GPG_KEY}

Your new client configuration file should be at ${HOME}/.config/camlistore/client-config.json.

You’ll get output like this:

2014/03/04 23:29:29 Your Camlistore identity (your GPG public key's blobref) is: sha1-0b40618f0b2f6ff90ede6dc4ca7c5231eedf508b
2014/03/04 23:29:29 Wrote "/home/ivucica/.config/camlistore/client-config.json"; modify as necessary.

Web UI

Web UI will be available at http://${hostname}:3179. If accessing from local machine, use http://localhost:3179.

If you are visiting from a remote server, edit ${HOME}/.config/camlistore/server-config.json and under auth set this: userpass:alice:secret:+localhost (replace ‘alice’ and ‘secret’). This uses the completely insecure PLAIN authentication; use this only as a last resort. If you absolutely need this, you should consider turning on HTTPS, too, or reverse-proxying using nginx with HTTPS, so that you’re at least not leaking the password over the wire. Your password is also, obviously, stored locally in plaintext. This is all a BAD idea, but okay for testing.

Uploading blobs, files and directories

./bin/camput blob bin/README  # uploads a raw blob with no metadata; no filename, no nothing
sha1-4a8b6d44e3030bf36f39f0e0415209f8319ce019

./bin/camput blob bin/README  # note -- same output
sha1-4a8b6d44e3030bf36f39f0e0415209f8319ce019

BLOBHASH=$(./bin/camput blob bin/README)  # store hash in a variable...
./bin/camget ${BLOBHASH}  # ... then get this blob and print it out:
This is where Camlistore binaries go after running "go run make.go" in
the Camlistore root directory.

./bin/camtool list  # observe: just one blob, size 102
sha1-4a8b6d44e3030bf36f39f0e0415209f8319ce019 102

./bin/camput file bin/README  # uploads file data + creates metadata blob
sha1-129583b2870e357b17468508c4b8345faf228695

./bin/camtool list  # Note, no new content blob (content is the same) -- but there is the metadata blob
sha1-129583b2870e357b17468508c4b8345faf228695 356
sha1-4a8b6d44e3030bf36f39f0e0415209f8319ce019 102

./bin/camget sha1-129583b2870e357b17468508c4b8345faf228695
{"camliVersion": 1,
  "camliType": "file",
  "fileName": "README",
  "parts": [
    {
      "blobRef": "sha1-4a8b6d44e3030bf36f39f0e0415209f8319ce019",
      "size": 102
    }
  ],
  "unixGroup": "ivucica",
  "unixGroupId": 1000,
  "unixMtime": "2014-03-04T23:21:29.152341812Z",
  "unixOwner": "ivucica",
  "unixOwnerId": 1000,
  "unixPermission": "0644"
}

This file is not a permanode so it didn’t appear in the web UI.

./bin/camput file --permanode bin/README
sha1-129583b2870e357b17468508c4b8345faf228695
sha1-55e987dc3d81da6e2188b45320d7ee9e29c1366e
sha1-60a25fc96f7ee1830a9e95ecfc4c2fc80da65371

Now if you visit the WebUI, you’ll see the file appeared there. (You may also see it appear live if you had the web UI open.)

First hash is the file metadata, second is a claim, and the third one is the permanode itself, which you can use in the web UI to reach the content.

What is a claim? Quoting:

If you sign a schema blob, it’s now a “signed schema blob” or “claim”. The terms are used pretty interchangeably but generally it’s called a claim when the target of the schema blob is an object’s permanode (see below).

Signing involves claiming interest by a user over a blob. Signing is done with the previously created GPG key. It is my probably incorrect understanding that blobs without owners could be garbage collected. I can’t find the documentation to verify this; please leave a comment or email me whether this is correct or incorrect.

To upload a directory and simultaneously provide a title and some tags, as well as create a permanode:

./bin/camput file --permanode --title="Camlistore Documentation" --tag=documentation,camlistore ./doc/
sha1-ff227e6af6647d2c3958824a036d7a362a89d675
sha1-36483f956312bc82bfbca307739e1d2e225ccc08
sha1-6a57222b2a1a5338a11a02ba3a34fd3b43bb92ee
sha1-8cd8a87d82af1dd12fb7dce1c21510420ec8b419
sha1-3f22e0468104c908292d07271d744cd95f925d52
sha1-75d3db43c8b07bf82d601d65375ec64f7769a4bf

Search system’s camtool describe

Ask the search system about an object:

{
  "meta": {
    "sha1-75d3db43c8b07bf82d601d65375ec64f7769a4bf": {
      "blobRef": "sha1-75d3db43c8b07bf82d601d65375ec64f7769a4bf",
      "camliType": "permanode",
      "size": 562,
      "permanode": {
        "attr": {
          "camliContent": [
            "sha1-ff227e6af6647d2c3958824a036d7a362a89d675"
          ],
          "tag": [
            "documentation",
            "camlistore"
          ],
          "title": [
            "Camlistore Documentation"
          ]
        },
        "modtime": "2014-03-04T23:55:05.941276174Z"
      }
    }
  }
}

Mounting Camlistore filesystem

You won’t be mounting the Camlistore filesystem; you’ll be mounting a Camlistore filesystem. But first, we need to prepare you a bit.

cammount uses FUSE. Mounting (and FUSE) needs appropriate root-level permissions to, well, mount a filesystem. So, let’s use sudo -E (-E to maintain ${HOME} et al so Camlistore can find configuration)?

Not so fast. The localhost auth that is still used here is doing checks on several levels. First, you need to be on the local host (check!). Second, the socket connecting to camlistored needs to come from the same UID as the one that is running camlistored. Your sudo‘ed cammount would be running with UID=0; your camlistored runs under 1000 or more. (Presuming Debian Wheezy here.) So, camlistored rejects the auth. Don’t bother sudo‘ing camlistored; it doesn’t want to be run as root.

Solution?

sudo -E adduser ${USER} fuse

Yes, you just add the user to the fuse group. You now need to create a new login session (e.g. log out and log in is fine) so the appropriate subsystems notice you are a member of a new group. (“Hey, you never need to reboot Linux.”)

Alright, now we’re good to go. Find the hash of a permanode you want to mount. You can use web UI to do so. It’ll even have a handy instruction on what to do! Quoting from web ui:

./bin/cammount /some/mountpoint sha1-ff227e6af6647d2c3958824a036d7a362a89d675

Or more sanely:

mkdir -p mountpoint/
./bin/cammount mountpoint/ sha1-ff227e6af6647d2c3958824a036d7a362a89d675

Open a new session, and observe how there is actual content in the mountpoint/ directory!

After shutting down cammount with ctrl+c, you might need to unmount using:

fusermount -u mountpoint/

Use mount to see if you need to do that.

If you skip the permanode, you’ll get a special filesystem with virtual directories such as at, date, recent, roots, tag… and even though you can’t see that directory, you can cd sha1-ff227e6af6647d2c3958824a036d7a362a89d675 and see the same directory as before.

Closing notes

  • I haven’t looked at alternative indexing engines or alternative blobstores. For example, Amazon S3, Google Drive, Google Cloud Storage, …
  • I haven’t looked at blobstore sync.
  • I haven’t managed to correctly use ‘publishing’, especially for /pics/ (which is an example given in the documentation).
  • I haven’t shown you camput attr which sets custom attributes on permanodes.
  • I find the idea of importers, especially IMAP importers, very appealing. The Flickr one is already there. An IMAP importer (at 51:40) and an IMAP server (at 51:57) was mentioned in the FOSDEM 2014 talk.
  • I also find the idea of a built-in SMTP server quite appealing (mentioned at 32:12).

Given that the Camlistore filesystem is mountable and splits files into chunks a-la GFS (although in chunks that are far smaller in size than 64MB quoted in the GFS whitepaper), and given that the talk was given as recently as February 2014, and given that there is enthusiasm on author’s side, I’m really looking forward to something that could truly grow into a personalized distributed filesystem.

OS X’s Terminal: Getting Home, End, PgUp, PgDn to work

Apple’s Terminal on a Macbook requires a weird combination of fn+shift+left/right, fn+shift+up/down to get Home, End, PgUp and PgDn to work. And that still causes issues in a couple of places.

Despite maintaining my philosophy of “use defaults wherever possible”, I’ve decided to ditch iTerm and iTerm2 for a simple reason: after quitting from Apple’s Terminal, upon restart in Lion I get a screenful of information from my previous session. Quite handy if I had to restart a machine for some reason, but I don’t want to lose the context!

Here are two fixes found Francois Planque’s post.

First part involves fixing the escape sequences sent by the Terminal. Open Preferences (for example, by hitting Cmd+,), and navigate to Settings tab, then for the profile you want to adjust, navigate to Keyboard tab.

Over there, define the following escape sequences upon pressing home, end, page up and page down:

home: \033[1~
end: \033[4~
page up: \033[5~
page down: \033[6~

If you mess up something during input, use your mouse to hit the button “Delete one character”. To get \033 in the dialog box, just press the Escape key instead of typing backslash, zero, three, three.

After applying this, voila! vim and mc now type these keys correctly.

But, you’ve just messed up bash.

Second fix involves editing ~/.inputrc (or /etc/inputrc). Neither of these rc files existed on my machine. From Garret LeSage‘s blog post (and as suggested in a comment on Francois’s blog), I simply copy pasted the following:

"\e[1~": beginning-of-line
"\e[4~": end-of-line
"\e[5~": beginning-of-history
"\e[6~": end-of-history
"\e[3~": delete-char
"\e[2~": quoted-insert
"\e[5C": forward-word
"\e[5D": backward-word
"\e\e[C": forward-word
"\e\e[D": backward-word
set completion-ignore-case On

It’s nice to see an OS X-related tech post that’s still as useful in 2012 as it was in 2005. And it’s even nicer to see that it was originally intended for other UNIX and UNIX-style systems.

By the way: this post’s ID is 2 * 333. Make of it whatever you want. :-)