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Taking screenshots isn't allowed by the app after upgrading to Android 11

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Re: Taking screenshots isn't allowed by the app after upgrading to Android 11

#91

Post by rsynnott »

jbirer wrote: post #16
JosephRedfern wrote: post #8

Fun fact: 5/6 years ago, a bunch of Huawei phones came with world readable /dev/fb0 (framebuffer) device files. This made it trivial for any application to read the display, totally bypassing any Android screenshot/screen recording API (not that one existed at the time). Some of those devices also had readable /dev/event/input* files, which allowed touchscreen interaction to be monitored.

Sounds like a good backdoor with plausible deniability ("the dev forgot to restore permissions").

I think Hanlon's razor applies. This sort of shoddy work was pretty common in early Android phones, as companies with little software experience adapted to being OS vendors.

Here's another similar in concept (though much worse) one from Samsung: https://nvd.nist.gov/vuln/detail/CVE-2012-6422

Re: Taking screenshots isn't allowed by the app after upgrading to Android 11

#92

Post by asutekku »

badjeans wrote: post #9
asutekku wrote: post #7

Earlier quoted context omitted.

It’s to prevent you screenshotting snaps / disappearing messages sent to you or to prevent screenshotting licensed content. This is good for 99% of the people.

Can it prevent the user from taking a photo of the phone screen with a different device?

It does not prevent, but most people will not bother.

Re: Taking screenshots isn't allowed by the app after upgrading to Android 11

#93

Post by phendrenad2 »

jakub_g wrote: post #40
jkcxn wrote: post #28

Earlier quoted context omitted.

Are third party programs allowed to save screenshots unbeknown to the user in the first place??

In older Androids it was too easy for the app to get the permission to capture/record the screen without clear user consent. In newer Androids you need to ask permission at runtime.

So Chrome and Firefox should check if they're on a new or old Android.

Re: Taking screenshots isn't allowed by the app after upgrading to Android 11

#94

Post by phendrenad2 »

jtvjan wrote: post #41
rzk wrote: post #3

Anyone else noticed that you can't take screenshots on Android when using Chrome Incognito mode? "Can't take screenshot due to security policy". I don't understand the rationale behind it. Why can't I take a screenshot of my own phone?

It's to stop a preview from showing up in the recents screen. Try loading a page in incognito mode and then pressing the overview button. Notice that you just see a grey square instead of the page you loaded.

Why would app preview be conflated with whether the user can take a screenshot? Can't those be two separate options?

Re: Taking screenshots isn't allowed by the app after upgrading to Android 11

#95

Post by phendrenad2 »

dalu wrote: post #88
ffpip wrote: post #53

Earlier quoted context omitted.

To prevent accidental screenshots of you watching porn?

Since when does Google allow you to watch porn? They do everything to fight it. You can't even install legit porn apps without manually downloading the apk. And then it only works on your phone and tablet, not the TV where it would actually be desired to work. Also what right does Google have to tell me what I can and can't watch on my TV/device?

iOS too. Porn apps are expressly forbidden.

Re: Taking screenshots isn't allowed by the app after upgrading to Android 11

#96

Post by grishka »

opencl wrote: post #80
grishka wrote: post #46

Earlier quoted context omitted.

> Won't unlocking the bootloader make banking apps not work anymore? Depends on how paranoid your bank is. There's this SafetyNet thing that checks for "system integrity". It's part of Google Services. For now , it's possible to bypass these checks using Magisk, but I've read that Google is testing the new method involving TrustZone — a hardware trusted execution environment within the SoC where you aren't one of the…

You can re-lock the bootloader with your own signing key on Pixels. GrapheneOS seems to be the only third party ROM currently taking advantage of it.

TIL about `fastboot flash avb_custom_key`. Certainly better than nothing, but seeing how it shows a warning on each boot in this mode, it most probably trips SafetyNet as well.

Re: Taking screenshots isn't allowed by the app after upgrading to Android 11

#97

Post by yiyus »

swiley wrote: post #66
_odey wrote: post #38

Earlier quoted context omitted.

Won't unlocking the bootloader make banking apps not work anymore? Had this issue when I tried LineageOS on my old phone, and I really like the convenience of those apps as opposed to using the website, which is extremely bad. Also, how do I do all you said above? (I need a step by step tutorial). Also is it reversible? Are there any other security implications?

>make banking apps not work anymore If you live in a country where you have to use your phone for banking and can't use the web then you need to talk to your politicians. That seems like a pretty extreme violation of your freedom. As much as I dislike the US at least we don't have that.

In which kind of bubble do you live where not making web apps available for your clients is seen as an extreme violation of freedom? As long as it is possible to go to the bank to do whatever you need to do, I do not think politicians have anything to say.

Sometimes you don't have to, but it's much more convenient. For example, I can use my bank app just with my fingerprint. To use the web app, I either have to login with my phone (reading a QR code) or have to use one of those devices where you insert your card and enter a couple of codes (if I find it...).

Re: Taking screenshots isn't allowed by the app after upgrading to Android 11

#98

Post by jakub_g »

phendrenad2 wrote: post #93
jakub_g wrote: post #40

Earlier quoted context omitted.

In older Androids it was too easy for the app to get the permission to capture/record the screen without clear user consent. In newer Androids you need to ask permission at runtime.

So Chrome and Firefox should check if they're on a new or old Android.

It's only a part of the issue. The other part is that a "launcher" app shows miniatures of apps when you scroll through open apps, and this behavior is controlled by the same screen capturing permission. When you enable screenshots, you also enable previews in the launcher app when switching between apps, in some cases it might be not desirable.

There's probably some more nuances that I'm not aware of.

Re: Taking screenshots isn't allowed by the app after upgrading to Android 11

#99

Post by phendrenad2 »

exabrial wrote: post #68

Take another phone, aim at screen, take screen shot. It's a stupid "feature" that lulls user's into a false sense of security. The real motivation is to prevent badly behaved apps from taking screenshots in the background, but requiring the user shortcut input to do that would be more secure and a better option.

The real motivation is preventing badly behaved apps from taking screenshots in the background, without investing any engineering effort into adding the correct user warnings and settings to differentiate between intended and unintended screenshots.
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