[Pkg-chromium-maint] Bug#883746: chromium: secretly stores referer and url for downloaded files

[Adam Borowski]

Package: chromium
Version: 62.0.3202.89-1
Severity: important

Hi!
If you download and save a file with Chromium (even in incognito mode), it
saves potentially sensitive metadata in a way that's completely unknown to
almost all users, even highly technical ones:

user.xdg.referrer.url: https://angband.pl/tmp/
user.xdg.origin.url: https://angband.pl/tmp/20130210_001.jpg

This photo is embarassing, but not overwhelmingly so.  It also, on its own,
appears to include no way to tie to me in particular.  There's EXIF but,
coming from a sane camera, it has no GPS data or whatever.  Yet, once the
URL is smuggled, the link to me is obvious, and it's easy to distort the
image's story into something that could get someone fired or otherwise
publicly shamed (based on typical kitten behaviour).

And it can get worse: imagine (werewolf protection) a kiddie porn image,
or a secret government file ("Hillary and Donald, sitting in a tree,
K.I.S.S.I.N.G.jpg").

In this case, referer is uninteresting, but it can be as bad or worse than
the URL itself.

This is a concern when the file is copied to any xattr-preserving media,
such as an USB stick or a CIFS mount -- or, if your computer itself is
imaged/accessed.


Meow!
-- System Information:
Debian Release: buster/sid
  APT prefers unstable-debug
  APT policy: (500, 'unstable-debug'), (500, 'unstable'), (500, 'testing'), (150, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.15.0-rc2-debug-00195-g50510b7395bf (SMP w/5 CPU cores)
Locale: LANG=C.UTF-8, LC_CTYPE=C.UTF-8 (charmap=UTF-8), LANGUAGE=C.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: sysvinit (via /sbin/init)

Versions of packages chromium depends on:
ii  chromium-common      62.0.3202.89-1
ii  libasound2           1.1.3-5
ii  libatk1.0-0          2.26.1-1
ii  libavcodec57         7:3.4-4
ii  libavformat57        7:3.4-4
ii  libavutil55          7:3.4-4
ii  libc6                2.25-3
ii  libcairo2            1.15.8-2
ii  libcups2             2.2.6-2
ii  libdbus-1-3          1.12.2-1.0nosystemd1
ii  libevent-2.1-6       2.1.8-stable-4
ii  libexpat1            2.2.3-2
ii  libflac8             1.3.2-1
ii  libfontconfig1       2.12.6-0.1
ii  libfreetype6         2.8.1-0.1
ii  libgcc1              1:7.2.0-17
ii  libgdk-pixbuf2.0-0   2.36.11-1
ii  libglib2.0-0         2.54.2-1
ii  libgtk2.0-0          2.24.31-4
ii  libharfbuzz0b        1.7.1-1
ii  libicu57             57.1-8
ii  libjpeg62-turbo      1:1.5.2-2+b1
ii  liblcms2-2           2.8-4
ii  libminizip1          1.1-8+b1
ii  libnspr4             2:4.16-1+b1
ii  libnss3              2:3.34-1
ii  libopus0             1.2.1-1
ii  libpango-1.0-0       1.40.13-2
ii  libpangocairo-1.0-0  1.40.13-2
ii  libpng16-16          1.6.34-1
ii  libpulse0            11.1-3.0nosystemd1
ii  libre2-3             20170101+dfsg-1
ii  libsnappy1v5         1.1.7-1
ii  libstdc++6           7.2.0-17
ii  libvpx4              1.6.1-3
ii  libwebp6             0.6.0-4
ii  libwebpdemux2        0.6.0-4
ii  libwebpmux3          0.6.0-4
ii  libx11-6             2:1.6.4-3
ii  libx11-xcb1          2:1.6.4-3
ii  libxcb1              1.12-1
ii  libxcomposite1       1:0.4.4-2
ii  libxcursor1          1:1.1.14-3
ii  libxdamage1          1:1.1.4-3
ii  libxext6             2:1.3.3-1+b2
ii  libxfixes3           1:5.0.3-1
ii  libxi6               2:1.7.9-1
ii  libxml2              2.9.4+dfsg1-5.1
ii  libxrandr2           2:1.5.1-1
ii  libxrender1          1:0.9.10-1
ii  libxslt1.1           1.1.29-5
ii  libxss1              1:1.2.2-1+b2
ii  libxtst6             2:1.2.3-1
ii  zlib1g               1:1.2.8.dfsg-5

Versions of packages chromium recommends:
ii  fonts-liberation  1:1.07.4-5

Versions of packages chromium suggests:
pn  chromium-driver    <none>
pn  chromium-l10n      <none>
pn  chromium-shell     <none>
pn  chromium-widevine  <none>

-- no debconf information