Hello Matthew, 

Thanks for the quick reply! And no worries at all. 

Glad to hear that the team is aware of the problem! I think that switching back to GETs (I believe this was the behavior before v10) wouldn’t significantly increase the threat of should surfing. With the current configuration, the search is still visible on the search results page itself, and after clicking on a linked page the text of the search is still visible in the browser’s back button. 

I think this regression has the potential to seriously impact the browser’s usability, because when following links in search, a significant percent of linked websites block Tor users. When a user encounters a page which blocks them, they will probably try to return to the search results to try another website. Crucially, the back button not returning to the search results breaks this workflow.

How does decision-making for issues like this typically work? If I’d like to help fix this issue, do you have any recommendations (e.g., should I open a PR with a fix)? 

Thank you!
-Peter 

On Nov 18, 2020, at 4:20 PM, Matthew Finkel <sysrqb@torproject.org> wrote:

On Wed, Nov 18, 2020 at 03:59:15PM -0500, Peter Story wrote:
I reported this usability problem on the tor-talk list but received no replies, so I thought I’d try here. For some context, I’m a researcher at Carnegie Mellon University, and I’m considering running a user-study involving Tor Browser in the coming months. I think this usability problem might negatively impact users (in my study, and at large), so I thought I should bring it to your attention. 


Hi Peter,

Thanks for sending this mail and following up. I apologize for the lack
of response, we're all overloaded.

This is a known usability issue. It arises from the fact that Tor
Browser sends the initial search query via a POST request. The breakage
occurs because the "Back" action triggers a GET request for the previous
site and it does not re-play the original POST request. I assume the
reasoning for this is that POST requests are not assumed to be
idempotent, whereas GET requests are. I'm not sure how best we can solve
this except switching to using GET, however this places all queries into
the URL bar and then they become vulnerabilbe to shoulder-surfing as
such. That probably a necessary trade-off, though.


I’m seeing a small but annoying usability problem in v10 of Tor Browser (tested with 10.0.2 on a Mac). Replication:

Open a new window
Search using either the URL bar or the “Search with DDG” field. On the page with search results, note that the page’s URL doesn’t contain the search query in the URL parameters.
Click on a link in the search results
Click the back button
Actual behavior: you are returned to a blank search page
Expected behavior: you are returned to your search results

I don’t see this problem in the latest version of Firefox, 82.0.3, and I don’t remember seeing this problem before Tor Browser v10. Also, I do not see this problem for searches conducted with Google in Tor Browser. 

I’m wondering whether this was an intentional change, or something that should be fixed. Hopefully it's an easy fix: if the search is conducted using URL parameters, then the back button should work as expected. 

Sincerely,
-Peter Story
PhD Student


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