Google Pixel bug lets you “uncrop” the last four years of screenshots
arstechnica.com
New tool reveals cropped-out screenshot info isn't deleted, can be recovered.

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Google Pixel bug lets you “uncrop” the last four years of screenshots
New tool reveals cropped-out screenshot info isn't deleted, can be recovered.

Back in 2018, Pixel phones gained a built-in screenshot editor called "Markup" with the release of Android 9.0 Pie. The tool pops up whenever you take a screenshot, and tapping the app's pen icon gives you access to tools like crop and a few colored drawing pens. That's very handy assuming Google's Markup tool actually does what it says, but a new vulnerability points out the edits made by this tool weren't actually destructive! It's possible to uncrop or unredact Pixel screenshots taken during the past four years.

[...]

the Android 9 release of the Markup tool worked correctly and truncated the overwritten file. Android 10 brought a lot of dramatic "Scoped Storage" changes to how file storage worked in Android, though. It's unclear how or why this happened, but perhaps as part of that huge wave of file-handling commits, one undocumented change made it into the Android Framework file parser: the Framework's "write" mode stopped truncating overwritten files, and the bug in Markup was created. The Markup tool relied on the OS's file handling, and the way it worked changed in a later release, which it looks like nobody noticed.

        • robot_dog_with_gun [they/them]
          ·
          2 years ago

          there are use-cases or workflows where you want to drag the boundary around a little bit before committing to the change and it's annoying to go from not cropped at all to a harsh crop and then have to undo and redo the entire operation instead of sliding back a little bit and un-cropping a little bit.

          this also isn't the first time i've heard of digital cropping not quite doing what people think. i'd be surprised if there isn't some history with like chemical photo developing where cropping was done by non-destructively matting the negative and that's why cropping doesn't destroy all the data in photo shop and its derivatives, but physical photography is outside my expertise.

        • robot_dog_with_gun [they/them]
          ·
          2 years ago

          if the ui properly explained the operation then you'd catch these things. like, "I have this giant photo and crop down to 10% of it, why is the file size still the same?"