AUE chromebook: Preserving old extensions

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J Ender

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Jul 11, 2023, 1:37:57 PM7/11/23
to Chromium Extensions
I've had to learn to unpack and install old versions of extensions, however I would like to pack from my existing setup.

The help pages I find on the internet are for non-Chromebooks, and the same methodology does not work.

One webpage says: thread-225106802-3995018790331390142.png

But when I try using the profile path given by chrome://version; it says "Access to the file was denied"; or if using developer mode to pack - doesn't navigate to it.

As time goes on, I typically lose access to more and more extensions.  If one has disappeared from the chrome store (happens regularly), I should have a local copy - if I can just figure out how to pack it, I should be able to side load it after I powerwash.

PhistucK

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Jul 11, 2023, 2:32:27 PM7/11/23
to J Ender, Chromium Extensions
Just to verify, does going to the path mentioned in about:version using the browser (just copy-paste in the address bar) show any file list?
If so, you can browse the directory this way and get to your extensions. Otherwise, read on.

It is not an easy way, but all of the extension files are available when navigating to chrome-extension://(extension-id)/path/to/file, so you could theoretically download each of those, one by one or programmatically, but looking at the manifest (chrome-extension://(extension-id)/manifest.json) to get a clue and by monitoring the network panel of the developer tools for the extension. You might miss some circumstantial resources, though.

PhistucK


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J Ender

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Jul 11, 2023, 6:22:19 PM7/11/23
to Chromium Extensions, PhistucK, Chromium Extensions

Just to verify, does going to the path mentioned in about:version using the browser (just copy-paste in the address bar) show any file list?

Correct, no list of visible extensions.

It is not an easy way, but all of the extension files are available when navigating to chrome-extension://(extension-id)/path/to/file, so you could theoretically download each of those, one by one or programmatically, but looking at the manifest (chrome-extension://(extension-id)/manifest.json) to get a clue and by monitoring the network panel of the developer tools for the extension. You might miss some circumstantial resources, though.

Tried this example to see if anything came up: 

chrome-extension://mmfbcljfglbokpmkimbfghdkjmjhdgbg/path/to/file 

Got: 

invalid is blocked
Requests to the server have been blocked by an extension.
Try disabling your extensions.
ERR_BLOCKED_BY_CLIENT

Disabled my extensions, and still blocked.  Have not rebooted yet, as I am composing this message.

I still have some Chrome Apps running, but no extensions according to: chrome://extensions

While examining my Apps, I noticed my example is an App, and is enabled, figured maybe that was the issue.  Turned it off, re-tried the suggested path/to/file and got:

mmfbcljfglbokpmkimbfghdkjmjhdgbg is blocked

Requests to the server have been blocked by an extension.

Try disabling your extensions.
ERR_BLOCKED_BY_CLIENT

Turned off all Apps, still the latter (at least, more specific) error message.

PhistucK

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Jul 12, 2023, 4:18:19 AM7/12/23
to J Ender, Chromium Extensions
path/to/file was an example, not a real path.
chrome-extension://(extension-id)/manifest.json should always return something, though and reveal some file paths.

There is a chance that there are third party websites that collect .crx from the web store, by the way. I cannot vouch for them (maybe they add malicious stuff to it), but extracting the files from their .crx files (which are some kind of ZIP archives) might at least reveal the file list and you can download from chrome-extension://(extension-id)/... according to the file list to get the original, surely not modified by the third party, files

PhistucK

Max Nikulin

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Jul 13, 2023, 6:36:33 AM7/13/23
to chromium-...@chromium.org
On 12/07/2023 15:17, PhistucK wrote:
> There is a chance that there are third party websites that collect .crx
> from the web store, by the way. I cannot vouch for them (maybe they add
> malicious stuff to it)

Original .crx files are signed, so it should be possible to create a
tool (if it does not exist yet) that validates obtained files. Public
keys are likely in the chromium source code repository.

What may be more tricky is to realize the reason why a particular
extension is not available from the web store any more. There is a
chance that the original and properly signed file has been considered
malicious.
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