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Investigating an “evil” RJ45 dongle

(lcamtuf.substack.com)
508 points zdw | 6 comments | 17 Jan 25 20:41 UTC | HN request time: 1.263s | source | bottom
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bentcorner ◴[17 Jan 25 21:53 UTC] No.42743654[source]▶
I actually really appreciate USB devices that masquerade as a storage device to provide their own drivers. I suppose in this day and age the "right" thing to do is to upload a bunch of stuff to microsoft servers so that it downloads whatever is needed upon getting plugged in, but I've observed enough stuff needing manually installed drivers to know that this isn't as apparently easy as it may appear to be. (For example, I very often need to download vendor-specific ADB drivers)

Anyways, I think it's clever for peripherals to help you bootstrap, and having the drivers baked into the device makes things a little easier instead of trying to find a canonical download source.

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1. qwezxcrty ◴[17 Jan 25 22:20 UTC] No.42743890[source]▶
In this specific case it makes a bit more sense, as when you need to install a RJ45 dongle is likely when you don't have a network connection.
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2. Cthulhu_ ◴[18 Jan 25 09:44 UTC] No.42747125[source]▶
While that's true, you'd also expect USB network devices to be standardized and have builtin drivers under all the main operating systems.
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3. adrian_b ◴[18 Jan 25 11:03 UTC] No.42747502[source]▶
That would be desirable but it does not happen in practice.

All the USB network devices that I have ever used required specific drivers. Sometimes the drivers happened to be already bundled with the Linux kernel or with Windows, but frequently they were not.

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4. franga2000 ◴[18 Jan 25 13:52 UTC] No.42748306{3}[source]▶
Where do you buy such things? Every USB Ethernet card I've used in the last 10 years was either RNDIS or some version of USB-CDC. They've worked out of the box on both Linux, Windows and some even Android.
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5. adrian_b ◴[18 Jan 25 15:23 UTC] No.42749006{4}[source]▶
If you start the configuration of the Linux kernel and you go to "Device Drivers", then to "USB Network Adapters", you will notice that there are close to 50 such device drivers.

That should tell you that there are plenty of different USB Ethernet Adapters that you can find when buying one.

Among those that I have encountered more frequently have been several kinds of Realtek, and of ASIX, and of Aquantia.

Especially among the faster USB Ethernet adapters I doubt that there are many without custom drivers.

Some people may not notice this, if they are using only fat Linux kernels, with all the possible device drivers being enabled and compiled, but if you use a streamlined kernel, e.g. for instant booting, you may need to add a device driver whenever you buy such an Ethernet adapter.

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6. account42 ◴[20 Jan 25 11:57 UTC] No.42767764{5}[source]▶
> That should tell you that there are plenty of different USB Ethernet Adapters that you can find when buying one.

It doesn't tell you that at all. Linux contains tons of drivers for odd devices that you will never encounter in your lifetime.