carrier "subsidy" [LWN.net]

carrier "subsidy"

Posted Jan 29, 2014 7:12 UTC (Wed) by dlang (guest, #313)
In reply to: carrier "subsidy" by Del-
Parent article: Stallman on GCC, LLVM, and copyleft

> In reality, tethering can be blocked in numerous ways, locking down a device is not necessary.

Not really. If the mobile device doesn't tell the carrier that it's doing tethering, and instead uses the kernel masquerading functionality, the carrier can't tell what data originated from the phone and what originated from the network.

The most they can do is to be a mitm and look for things like user-agent values and block ones that they think are not on the phone (which breaks things for people who need to change their phone's user-agent to deal with a broken website)

David Lang

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carrier "subsidy"

Posted Jan 29, 2014 18:32 UTC (Wed) by Del- (guest, #72641) [Link] (8 responses)

> Not really. If the mobile device doesn't tell the carrier that it's doing tethering, and instead uses the kernel masquerading functionality, the carrier can't tell what data originated from the phone and what originated from the network.

It is quite easy to have the phone delivered with various software locks to the consumer. Of course, hackers can circumvent it, especially if it is open source. For instance the carriers over here preloads the phones with their own apps, and you can not remove them in the app manager. How many go through the trouble of circumventing it? I did, but I am willing to bet very few. A hacker easily circumvents just about any lock on an iphone too, and this is fairly well known.

What I am trying to say is that all you need to do is to make it awkward to enable tethering, and the lock will work for 95% of the users. Even make it a breach of the contract, and even fewer will attempt circumventing it. Among those 5% circumventing it at least a couple of them would circumvent it regardless of what you do. In conclusion, I don't see any real issue for vendors/carriers. They get their money typically through two year contracts, and who really needs to lock down anything when you have a two year contract securing all payback.

There is no question that many of the device vendors want the freedom to lock down devices, and hence do not want GPLv3 in parts of the software stack like boot-loader or init-system. Still, from what I have seen (which may or may not be representative), the vendors of network routers and NAS devices have no more issues bundling Samba than they have bundling linux. This leads me to believe that they would bundle linux too even if it was GPLv3. I may of course be wrong, and since nobody called the bluff we will probably never know.

carrier "subsidy"

Posted Jan 29, 2014 18:58 UTC (Wed) by dlang (guest, #313) [Link] (7 responses)

the statement that I was responding to was that there were lots of ways to prevent tethering without locking down the phone.

I say that without locking down the phone, it's easy to have tethering enabled by loading things on the phone

you reply that if the vender puts things on the phone that the user can't remove, they can prevent tethering. In my book, that's locking down the phone. If it's not locked down, the user can remove those things.

carrier "subsidy"

Posted Jan 29, 2014 23:01 UTC (Wed) by Del- (guest, #72641) [Link] (6 responses)

I think we are talking past eachother. I was simply talking about bundled apps and some modified system internals being enough to block most from tethering. With locking down the device I was thinking in the Tivo sense, which is quite different.

carrier "subsidy"

Posted Jan 30, 2014 1:51 UTC (Thu) by dlang (guest, #313) [Link] (5 responses)

I think we are using similar terms.

I'm saying that unless you do a tivo-type lockdown of the phone, your other bundled apps won't matter (if you decide to cripple the kernel that may be harder to fix)

If users can install their own stuff without a tivo type lockdown, then they can and will override whatever lockdown your bundled apps try to force.

carrier "subsidy"

Posted Jan 30, 2014 8:05 UTC (Thu) by Del- (guest, #72641) [Link] (4 responses)

> I'm saying that unless you do a tivo-type lockdown of the phone, your other bundled apps won't matter

I believe we disagree here. I believe very few people will alter the OS image shipped with a smartphone, even with access to all source code. Therefore, I believe simply disabling stuff in the shipping image is sufficient to block most customers from tethering.

> If users can install their own stuff without a tivo type lockdown, then they can and will override whatever lockdown your bundled apps try to force.

As I said, people do this to iphones today, so even with a tivo type lockdown they can and will override. For a company (be it vendor or carrier), I believe the real issue is how many would do it given a certain level of inconvenience.

carrier "subsidy"

Posted Jan 30, 2014 10:20 UTC (Thu) by dlang (guest, #313) [Link] (3 responses)

it's funny that you use the iphone, because that is an example of a tivo type locked down device.

carrier "subsidy"

Posted Jan 30, 2014 14:43 UTC (Thu) by Del- (guest, #72641) [Link] (2 responses)

> it's funny that you use the iphone, because that is an example of a tivo type locked down device.

Of course, that was why I used it as example. It is an example showing that in practise it is often impossible to lock down the device. Hence for any practical concerns whether you lock it down Tivo style or just make it inconvenient for the consumer to use it in unintended ways (like removing the tethering possibility from the system, requiring somebody to patch system internals to enable it again), can amount to the same end result for the vendor. They get their money, and they get fine grained control on what functionality the user has access to.

I have one very real life example of how ridiculous the Tivo stuff can be. As already mentioned HTC actually provides tools to unlock their devices, so you could say that those devices are not locked, but there is a level of inconvenience if you want to swap out the image it came with from the carrier. Now my daughter got a HTC Desire, and I wanted to flash a newer version of Android on it because HTC stopped providing newer versions of Android for it. I would say this is a prime example of what we are talking about here. I knew HTC provided tools, went over there downloaded the tools and started looking for documentation. I found the whole thing quite confusing, especially since it seemed geared towards windows users, and I only had linux. I ended up just deleting all of it, headed over to CyanogenMod and used their un-official tools to unlock the boot-loader, just as I did for my Tivotized Galaxy S2 earlier. You see, whether the device is Tivotized or not doesn't necessarily amount to much. Most funny part of the story? When I finally got the boot-loader unlocked, my daughter didn't want me to flash the device anyway. I usually follow the nerd slogan "if it works, fix it!", that may have something to do with it. I didn't even succeed in making my own daughter take advantage of the possibilities provided by an open device, simply because she did not trust anything but the official image from the carrier.

Moral of the story? Tivotization is plain stupid when it comes to consumers. I see no benefits for anybody. Even worse, as long as there is no software license pushing it away, I am afraid the madness will just continue for decades.

carrier "subsidy"

Posted Jan 31, 2014 0:04 UTC (Fri) by dlang (guest, #313) [Link]

I have several tivos that have been hacked for a _long_ time.

I am very aware that it's impossible to stop someone who's really determined.

However, lawsuits (or threats of lawsuits) against manufacturers are frequently based on how easy they make it to get at the data

and with the DMCA making it illegal to bypass even the most inept protections, there really is a point to them from a legal point of view.

Do not get me wrong, I think that these sorts of lockdowns, along with DRM are bad for customers, they don't stop the real bad guys and hurt legitimate users.

carrier "subsidy"

Posted Feb 3, 2014 11:34 UTC (Mon) by nye (guest, #51576) [Link]

>When I finally got the boot-loader unlocked, my daughter didn't want me to flash the device anyway. I usually follow the nerd slogan "if it works, fix it!", that may have something to do with it. I didn't even succeed in making my own daughter take advantage of the possibilities provided by an open device, simply because she did not trust anything but the official image from the carrier.

To be fair, HTC's version of Android 2.2 is far better than any stock Android I've ever used. Compared to the 4.x on my N7, it's faster, slimmer, easier to use, and less buggy. Plus all the features added in later versions are either completely worthless to me, or outright antifeatures.

Also, reflashing always comes with some degree of risk, especially if you hope to do so without resetting the device to factory defaults. Case in point: an OTA update to the aforementioned N7 a couple of months back rendered it unbootable, and I've not yet found the time to work out how to fix it without wiping it completely.

If you actually want to *use* a device for its intended purpose, rather than just having it as a toy, it's perfectly reasonable to want to keep to the path.