[tbb-bugs] #27013 [Applications/Tor Browser]: TBA: Audit thirdparty selfbraille

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#27013: TBA: Audit thirdparty selfbraille
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 Reporter:  sysrqb                        |          Owner:  tbb-team
     Type:  defect                        |         Status:  needs_review
 Priority:  Very High                     |      Milestone:
Component:  Applications/Tor Browser      |        Version:
 Severity:  Normal                        |     Resolution:
 Keywords:  tbb-mobile, tbb-proxy-bypass  |  Actual Points:
Parent ID:  #25851                        |         Points:
 Reviewer:                                |        Sponsor:
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Changes (by sysrqb):

 * status:  new => needs_review


Comment:

 This library creates a Binder IPC with the `BrailleBack` app
 (`com.googlecode.eyesfree.brailleback`). It verifies the SHA-1 hash of the
 signing key of the app before creating a background service for
 communicating with it.

 This library is probably proxy-safe, but the browser and Android OS (via
 `AccessibilityManager` [0]) **could** send arbitrary data over this IPC so
 `BrailleBack` could bypass the Tor Browser proxy. Currently, I don't see
 this happening. I believe Accessibility events are only sent when focus is
 changed in the app, so I don't see a proxy-bypass right now.

 Any opinions here? Close?

 [0]
 https://developer.android.com/reference/android/view/accessibility/AccessibilityManager

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/27013#comment:1>
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