Bug#810939: iceweasel: Iceweasel fails to download files

[toto]

Package: iceweasel
Version: 43.0.2-1+b1
Severity: important

Dear Maintainer,

I upgraded my testing box last Friday (2016-01-08) and this upgraded Iceweasel
to 43.0.2. Since next Monday Iceweasel stopped downloading files despite there
were no significant changes on the machine in the 2 days span.

Presently, out of the 2 usual users of this machine, only one of them is able
to download files using Iceweasel. The bug does not (yet :-/) shows on my
laptop also (running testing too).

For those reasons, I suspected a profile problem and created a brand new user
on the machine (the one from which I report this bug) to investigate this
problem.  I ran Iceweasel, pointed it to some PDF, LibreOffice of even .dsc file (on
the Debian site) URLs.

PDF files are first previewed in Iceweasel, which is expected (and reveals that
this is not a network related problem), but when I try to download them (in
order to save them locally) with the button at the top right of the previewer,
the toolbar big blue pointing down arrow sort of animates itself but nothing is
downloaded and displaying the download list exhibits "Échec" for the files
(which means /failure/ in French).

When I click on links pointing to LibreOffice or .dsc files the big blue
arrow /animates/ too and the word 'Échec' shows in the download list again.

I checked and changed the configured download directory without any success. I
try changing Iceweasel preferences for PDF file handling to "Always ask" with
no success: the dialog does not even show, only the big blue arrow animates and
still the word "Échec"... which seems to eliminate a directory permission
problem, except maybe on some cache folder (where?). I *can* write to /tmp, by
the way.

Please note that on my regular account where I have the DownThemAll extension,
I work around this bug using this extension. Maybe this shall be useful for you.

What puzzles me more is that the other regular account on the computer does not
(yet) have this problem.

Just to make it clear:
- I checked that the mime type was correctly set (e.g.
  application/pdf)
- I checked (using an apache instance the logs of which I can check)
  the file is really transmitted. If the Content-Disposition is "inline", then
  the PDF is previewed, if Content-Disposition is "attachment" the download fails
- for those file type for which there is no preview in Iceweasel, the download
  fails.
- I just made a new try with a second brand new user account created on the box.

Thanks in advance,

phep


-- Package-specific info:

-- Extensions information
Name: Default theme
Location: /usr/lib/iceweasel/browser/extensions/{972ce4c6-7e08-4474-a285-3208198ce6fd}
Package: iceweasel
Status: enabled

Name: Français Language Pack locale
Location: /usr/lib/iceweasel/browser/extensions/langpack-fr at iceweasel.mozilla.org.xpi
Package: iceweasel-l10n-fr
Status: enabled

-- Plugins information
Name: DjView-4.10.4
Location: /usr/lib/mozilla/plugins/nsdejavu.so
Package: djview-plugin
Status: enabled

Name: Gnome Shell Integration
Location: /usr/lib/mozilla/plugins/libgnome-shell-browser-plugin.so
Package: gnome-shell
Status: enabled

Name: Shockwave Flash (11.2.202.559)
Location: /usr/lib/flashplugin-nonfree/libflashplayer.so
Status: enabled


-- Addons package information
ii  djview-plugin  4.10.4-1     amd64        Browser plugin for the DjVu image
ii  gnome-shell    3.18.1-1     amd64        graphical shell for the GNOME des
ii  iceweasel      43.0.2-1+b1  amd64        Web browser based on Firefox
ii  iceweasel-l10n 1:43.0.2-1   all          French language package for Icewe

-- System Information:
Debian Release: stretch/sid
  APT prefers testing-proposed-updates
  APT policy: (500, 'testing-proposed-updates'), (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 4.3.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=fr_FR.utf8, LC_CTYPE=fr_FR.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages iceweasel depends on:
ii  debianutils               4.5.1
ii  fontconfig                2.11.0-6.3
ii  libasound2                1.0.29-1
ii  libatk1.0-0               2.18.0-1
ii  libc6                     2.21-6
ii  libcairo2                 1.14.4-1
ii  libdbus-1-3               1.10.6-1
ii  libdbus-glib-1-2          0.102-1
ii  libevent-2.0-5            2.0.21-stable-2+b1
ii  libffi6                   3.2.1-4
ii  libfontconfig1            2.11.0-6.3
ii  libfreetype6              2.6.1-0.1
ii  libgcc1                   1:5.3.1-5
ii  libgdk-pixbuf2.0-0        2.32.3-1
ii  libglib2.0-0              2.46.2-3
ii  libgtk2.0-0               2.24.29-1
ii  libhunspell-1.3-0         1.3.3-3+b2
ii  libnspr4                  2:4.11-1
ii  libnss3                   2:3.21-1
ii  libpango-1.0-0            1.38.1-1
ii  libsqlite3-0              3.9.2-1
ii  libstartup-notification0  0.12-4
ii  libstdc++6                5.3.1-5
ii  libvpx3                   1.5.0-2
ii  libx11-6                  2:1.6.3-1
ii  libxcomposite1            1:0.4.4-1
ii  libxdamage1               1:1.1.4-2+b1
ii  libxext6                  2:1.3.3-1
ii  libxfixes3                1:5.0.1-2+b2
ii  libxrender1               1:0.9.9-2
ii  libxt6                    1:1.1.5-1
ii  procps                    2:3.3.11-3
ii  zlib1g                    1:1.2.8.dfsg-2+b1

Versions of packages iceweasel recommends:
ii  gstreamer1.0-libav         1.6.2-1
ii  gstreamer1.0-plugins-good  1.6.2-1+b1

Versions of packages iceweasel suggests:
ii  fonts-lmodern          2.004.5-1
ii  fonts-stix [otf-stix]  1.1.1-4
ii  libcanberra0           0.30-2.1
ii  libgnomeui-0           2.24.5-3
ii  libgssapi-krb5-2       1.13.2+dfsg-4
pn  mozplugger             <none>

-- no debconf information