[tor-bugs] #25305 [- Select a component]: Tor Browser refuses to start / XDG_CONFIG_DIRS environment variable segfaults Tor Browser

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#25305: Tor Browser refuses to start / XDG_CONFIG_DIRS environment variable
segfaults Tor Browser
--------------------------------------+--------------------
     Reporter:  adrelanos             |      Owner:  (none)
         Type:  defect                |     Status:  new
     Priority:  Medium                |  Milestone:
    Component:  - Select a component  |    Version:
     Severity:  Normal                |   Keywords:
Actual Points:                        |  Parent ID:
       Points:                        |   Reviewer:
      Sponsor:                        |
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 More than 6 entries (each entry is devices by a colon) will segfault Tor
 Browser. Here is a simplified minimal example that shows how to trigger
 this bug.

 Happening with both, Tor Browser {{{7.5}}} and {{{8.0a1}}} on Debian
 stretch.

 **segfaults:**

 {{{
 XDG_CONFIG_DIRS=x:x:x:x:x:x:x ./start-tor-browser.desktop --debug
 }}}

 {{{./Browser/start-tor-browser: line 370:  3249 Segmentation fault
 TOR_CONTROL_PASSWD=${TOR_CONTROL_PASSWD} ./firefox --class "Tor Browser"
 -profile TorBrowser/Data/Browser/profile.default "${@}" < /dev/null}}}

 **working:**

 {{{
 XDG_CONFIG_DIRS=x:x:x:x:x:x ./start-tor-browser.desktop --debug
 }}}

 This is to show that the existence or content of the folder is unrelated
 here.

 **Relevance:**

 Of course nobody uses {{{XDG_CONFIG_DIRS=x:x:x:x:x:x}}} as their
 {{{XDG_CONFIG_DIRS}}}.

 Real world example that is failing is in Whonix, where settings are pre-
 configured. Whonix is using:

 {{{
 XDG_CONFIG_DIRS=/usr/share/torbrowser-default-browser/:/usr/share
 /security-misc/:/usr/share/kde-apper-no-autoupdate/:/usr/share/anon-ws-
 kde-startmenu/:/usr/share/anon-apps-config/:/usr/share/open-link-
 confirmation/:/etc/xdg
 }}}

 That segfaults Tor Browser.

 firefox-esr (from Debian stretch) does not have this issue.

 #21804 was a similar issue where a long {{{XDG_CONFIG_DIRS}}} environment
 variable resulted in Tor Browser refusing to start.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/25305>
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