Got a 11x44 LED badge labelled S1144. It identifies as

usb 1-2: new full-speed USB device number 61 using xhci_hcd
usb 1-2: New USB device found, idVendor=0416, idProduct=5020, bcdDevice= 1.00
usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
usb 1-2: Product: CH546
usb 1-2: Manufacturer: wch.cn
hid-generic 0003:0416:5020.0090: hiddev1,hidraw2: USB HID v1.00 Device [wch.cn CH546] on usb-0000:02:00.0-2/input0

The CH546 is a 8051 MCU. It uses a USB HID interface. There is some Windows software to program it.

Here's what lsusb -v -v -v has to say about it:

Bus 001 Device 062: ID 0416:5020 Winbond Electronics Corp. CH546
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               1.10
  bDeviceClass            0 
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0        64
  idVendor           0x0416 Winbond Electronics Corp.
  idProduct          0x5020 
  bcdDevice            1.00
  iManufacturer           1 wch.cn
  iProduct                2 CH546
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x0029
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          4 wch.cn
    bmAttributes         0xa0
      (Bus Powered)
      Remote Wakeup
    MaxPower               70mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      0 
      bInterfaceProtocol      0 
      iInterface              5 wch.cn
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.00
          bCountryCode            0 Not supported
          bNumDescriptors         1
          bDescriptorType        34 Report
          wDescriptorLength      34
          Report Descriptor: (length is 34)
            Item(Global): Usage Page, data= [ 0x00 0xff ] 65280
                            (null)
            Item(Local ): Usage, data= [ 0x01 ] 1
                            (null)
            Item(Main  ): Collection, data= [ 0x01 ] 1
                            Application
            Item(Local ): Usage, data= [ 0x02 ] 2
                            (null)
            Item(Global): Logical Minimum, data= [ 0x00 ] 0
            Item(Global): Logical Maximum, data= [ 0x00 0xff ] 65280
            Item(Global): Report Size, data= [ 0x08 ] 8
            Item(Global): Report Count, data= [ 0x40 ] 64
            Item(Main  ): Input, data= [ 0x06 ] 6
                            Data Variable Relative No_Wrap Linear
                            Preferred_State No_Null_Position Non_Volatile Bitfield
            Item(Local ): Usage, data= [ 0x02 ] 2
                            (null)
            Item(Global): Logical Minimum, data= [ 0x00 ] 0
            Item(Global): Logical Maximum, data= [ 0x00 0xff ] 65280
            Item(Global): Report Size, data= [ 0x08 ] 8
            Item(Global): Report Count, data= [ 0x40 ] 64
            Item(Main  ): Output, data= [ 0x06 ] 6
                            Data Variable Relative No_Wrap Linear
                            Preferred_State No_Null_Position Non_Volatile Bitfield
            Item(Main  ): End Collection, data=none
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               1
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x02  EP 2 OUT
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               1
Device Status:     0x0000
  (Bus Powered)

posted at: 21:22 | path: /programming | permanent link

Another nice article showing off DNSSEC strength...

Generate SSHFP DNS records for by host (pmeerw.net):

$ ssh-keygen -r @
@ IN SSHFP 1 1 3b00267ed86c211026e6d8b8eb5d9a7d9e51cf7d
@ IN SSHFP 1 2 189d464e8a13d2df66d882afdcb4220fb281ba1f19eda96aa35bf1a50188b0a7
@ IN SSHFP 2 1 adb06e3c4de279d2338bbec35a9a64c8661fb431
@ IN SSHFP 2 2 50e72d460ea86ad416b74b71f9b0c948bf42004ebf730290eff9d43fea9545a6
@ IN SSHFP 3 1 aaa45514f6bd534448ab7f09842fe1e13c269142
@ IN SSHFP 3 2 cc68f391aea002966cc3d7e84ce41dc73d4cfb6c2381e5b665f26603f8317dd3
@ IN SSHFP 4 1 7482ed5e3e6621978bd0bbd61f6b9740dcef252c
@ IN SSHFP 4 2 eb77b6f29bee067d6524459e4cfc696881bd70908d514be682cb068746729594

SSH can silently connect to an SSH server (without asking to verify the host fingerprint!) if VerifyHostKeyDNS is enabled: ssh -o VerifyHostKeyDNS=yes pmeerw@pmeerw.net.

posted at: 22:58 | path: /configuration | permanent link

RFC7929 describes a way to put OpenPGP public keys into DNS using DANE. Here's an article which I shamelessly condense here...

There is a DNS resource record that stores the complete public key. I'm using ECC to bring down key size. It looks like this:

c746aa6d791946caf1aade6dc6c5e720e6e79d650e5b882dc11a2078._openpgpkey.pmeerw.net. IN OPENPGPKEY (
                  mDMEY54vtRYJKwYBBAHaRw8BAQdAmhK78RNv+Azsrrcgnb4Ijf4JwEOfHM8D
                  paY2yy1w0oG0KlBldGVyIE1lZXJ3YWxkLVN0YWRsZXIgPHBtZWVyd0BwbWVl
                  cncubmV0PoiQBBMWCAA4FiEE5u5nS8lBNCYy5igrw5J6UWK+XtEFAmOeL7UC
                  GwMFCwkIBwIGFQoJCAsCBBYCAwECHgECF4AACgkQw5J6UWK+XtE+dAD/dZAp
                  If2WWK2fAQgGIxOepBr6Nj2g6Z78W25wyYiSxvIA/1VtCuCsveRGmKZ0wnuQ
                  kJP4z3v+r/XdjRJeingYSnsKuDgEY54vtRIKKwYBBAGXVQEFAQEHQPCrzg3G
                  IRhYWFdUkps1DSqmLEZ5xQX6D96jYpq28Lp1AwEIB4h4BBgWCAAgFiEE5u5n
                  S8lBNCYy5igrw5J6UWK+XtEFAmOeL7UCGwwACgkQw5J6UWK+XtGQyQD/RD1d
                  zIk/Kjnb1yKcW+GAIHkpahgEQzpk7Bcxk38ReaAA/j2ZoXGMeMNVlJdOIv7d
                  gr/Hw9ygwxInPg9Nth2wpKoB
)

The name part is the SHA-256 hash of "pmeerw". You can use the command openpgpkey --create pmeerw@pmeerw.net to create the record (install the Debian/Ubuntu hash-slinger package).

Try openpgpkey.info to query a PGP public key!

posted at: 22:49 | path: /configuration | permanent link

Got a 16x16 Divoom Pixoo pixel art frame, a Bluetooth connected device with a small battery in a nice case. It can blink pixels. There's an app and Github repo with Python code.

Still, getting the think to run was a bit of a challenge on Ubuntu 22.04... First, it show up as a Bluetooth device:

$ hcitool scan
Scanning ...
	11:75:58:xx:xx:xx	Pixoo

Then, one can check if RFCOMM is available using sdptool:

$ sdptool browse 11:75:58:xx:xx:xx
Browsing 11:75:58:xx:xx:xx ...
Service Name: Serial Port 1
Service RecHandle: 0x10004
Service Class ID List:
  "Serial Port" (0x1101)
Protocol Descriptor List:
  "L2CAP" (0x0100)
  "RFCOMM" (0x0003)
    Channel: 1

Note the channel number (1), older Divoom devices use (4) here.

Next, there's an issue with Ubuntu's python3-pybluez package (0.23-4build1) in 22.04/jammy:

self.sock.send(bytes(package))
  File "", line 3, in send
SystemError: PY_SSIZE_T_CLEAN macro must be defined for '#' formats

It's an issue with Python 3.10 and apparently a special flag macro must be #defined when compiling the library. Luckily, this can be easily fixed by installing the python3-pybluez 0.23-5 package from 22.10/kinetic.

posted at: 13:11 | path: /fun | permanent link

OpenAI's chat is all the rage currently, so I have it a try with a well-known MBA expression: E=(x^y)+2*(x&y). This should simplify (spoiler alert) to x+y, however...

I'm not so convinced about the result, but nevertheless impressed by the answer. Also, I didn't quite get what the 'open' part in openai.com is...

posted at: 11:51 | path: /rant | permanent link