Chromium tweaks
Related articles
Contents
-
1 Browsing experience
- 1.1 chrome://xxx
- 1.2 Broken icons in Download tab
- 1.3 Chromium overrides/overwrites Preferences file
- 1.4 Search engines
- 1.5 Tmpfs
- 1.6 Launch a new browser instance
- 1.7 Directly open *.torrent files and magnet links with a torrent client
- 1.8 Touch Scrolling on touchscreen devices
- 1.9 Disable system tray icon
- 2 Profile maintenance
- 3 Security
- 4 Making flags persistent
- 5 See also
Browsing experience
chrome://xxx
A number of tweaks can be accessed via typing chrome://xxx in the URL field. A complete list is available by typing chrome://chrome-urls into the URL field. Some of note are listed below:
- chrome://flags - access experimental features such as WebGL and rendering webpages with GPU, etc.
- chrome://plugins - view, enable and disable the currently used Chromium plugins.
- chrome://gpu - status of different GPU options.
- chrome://sandbox - indicate sandbox status.
- chrome://version - display version and switches used to invoke the active
/usr/bin/chromium
.
An automatically updated, complete listing of Chromium switches is available here.
Broken icons in Download tab
If Chromium shows icon placeholders (icons representing broken documents) instead of appropriate icons in its Download tab, the likely cause is that the gnome-icon-theme package is not installed.
Chromium overrides/overwrites Preferences file
If you enabled syncing with a Google Account, then Chromium will override any direct edits to the Preferences file found under $HOME/.config/chromium/Default/Preferences
. To work around this, start Chromium with the --disable-sync-preferences
switch:
$ chromium --disable-sync-preferences
If Chromium is started in the background when you login in to your desktop environment, make sure the command your desktop environment uses is:
$ chromium --disable-sync-preferences --no-startup-window
Search engines
Make sites like wiki.archlinux.org and wikipedia.org easily searchable by first executing a search on those pages, then going to Settings > Search and click the Manage search engines.. button. From there, "Edit" the Wikipedia entry and change its keyword to w (or some other shortcut you prefer). Now searching Wikipedia for "Arch Linux" from the address bar is done simply by entering "w arch linux".
Tmpfs
Cache in tmpfs
To limit Chromium from writing its cache to a physical disk, one can define an alternative location via the --disk-cache-dir=/foo/bar
flag:
$ chromium --disk-cache-dir=/tmp/cache
Cache should be considered temporary and will not be saved after a reboot or hard lock. Alternatively, use:
/etc/fstab
tmpfs /home/username/.cache tmpfs noatime,nodev,nosuid,size=400M 0 0
Profile in tmpfs
Relocate the browser profile to a tmpfs filesystem, including /tmp
, or /dev/shm
for improvements in application response as the entire profile is now stored in RAM.
Use an active profile management script for maximal reliability and ease of use.
profile-sync-daemonAUR is such a script and is directly available from the AUR. It symlinks and syncs the browser profile directories to RAM. Refer to the Profile-sync-daemon wiki article for additional information on it.
Launch a new browser instance
When you launch the browser, it first checks if another instance using the same profile is already running. If there is one, the new window is associated with the old instance. To prevent this, you can specifically ask the browser to run with a different profile.
$ chromium --user-data-dir=<PATH TO A PROFILE>
Directly open *.torrent files and magnet links with a torrent client
By default, Chromium downloads *.torrent
files directly and you need to click the notification from the bottom-left corner of the screen in order for the file to be opened with your default torrent client. This can be avoided with the following method:
- Download a
*.torrent
file. - Right-click the notification displayed at the bottom-left corner of the screen.
- Check the "Always Open Files of This Type" checkbox.
For torrent magnet links to open with Deluge automatically when they are clicked, run the following commands:
$ gvfs-mime --set x-scheme-handler/magnet deluge.desktop $ xdg-mime default deluge.desktop x-scheme-handler/magnet
Touch Scrolling on touchscreen devices
Chrome and Chromium do not support touchscreen by default. There are a couple settings you can change in the "Flags" portion of Chrome to potentially make it work for your device. This has been tested in chromium from the official repositories and google-chromeAUR from the AUR.
- Browse to chrome://flags and set everything to default
- Switch "Enable Touch events" to "Enabled" (chrome://flags/#touch-events)
- Restart Chrome and touch scrolling should work. If it does not, it is worth trying the other modes that are available.
Known bugs:
- Touch Scrolling sometimes stops working after resuming from suspend. Restarting the browser seems to fix it.
- Touching tabs to switch to them is unstable. There is no known fix for this yet.
- You may need to specify which touch device to use. Find your touchscreen device with
xinput list
then launch Chromium with the--touch-devices=x
parameter, where "x" is the id of your device.
Disable system tray icon
Open the URL chrome://flags
in the browser. Disable this flag:
-
device-discovery-notifications
Click the restart button at the bottom of the page.
Profile maintenance
Chromium uses Sqlite databases to manage history and the like. Sqlite databases become fragmented over time and empty spaces appear all around. But, since there are no managing processes checking and optimizing the database, these factors eventually result in a performance hit. A good way to improve startup and some other bookmarks- and history-related tasks is to defragment and trim unused space from these databases.
profile-cleanerAUR and browser-vacuumAUR in the AUR do just this.
Security
Disable insecure RC4 cipher
The RC4 cipher has been declared as insecure, but the cipher is still in Chromium at present. To disable it:
$ chromium --cipher-suite-blacklist=0x0001,0x0002,0x0004,0x0005,0x0017,0x0018,0xc002,0xc007,0xc00c,0xc011,0xc016,0xff80,0xff81,0xff82,0xff83
You can check which cipher suites are supported by your browser at https://cc.dcsec.uni-hannover.de/. Make sure to visit this page before and after you make the change to verify that the change was effective.
To make the change persistent, you can modify ~/.config/chromium-flags.conf
and add the flags above. To check, open the website mentioned before. An alternative is to grep inside of your process list for the keyword "cipher".
External Information
There is no cleaner way to disable RC4. Also, the source-code only shows the right hexadecimal value for the single cipher. See Wikipedia:RC4 for basic information and a recommendation to disable RC4.
German Blog showing how to disable RC4 in common browsers.
User Agent
By default, Chromium already sends an excessively detailed User Agent, as is viewable via the EFF's Panopticlick test. This alone makes each browser readily identifiable with high accuracy, and is further exacerbated by the use of non-stable versions (for example, versions not recently provided by Google's release channels, or versions customized by a distribution).
However, this User Agent can be arbitrarily modified at the start of Chromium's base instance via its --user-agent="[string]"
parameter.
For the same User Agent as the stable Chrome release for Linux i686 (at the time of writing, the most popular Linux edition of Chrome) one would use:
--user-agent="Mozilla/5.0 (X11; Linux i686) AppleWebKit/535.2 (KHTML, like Gecko) Chrome/20.0.1132.47 Safari/536.11"
An official, automatically updated listing of Chromium releases which also shows the included WebKit version is available as the OmahaProxy Viewer.
SSL certificates
Chromium does not have an SSL certificate manager. It relies on the NSS Shared DB ~/.pki.nssdb
. In order to add SSL certificates to the database, users will have to use the shell.
Adding CAcert certificates for self-signed certificates
Grab the CAcerts and create an nssdb
, if one does not already exist. To do this, first install the nss package, then complete these steps:
$ mkdir -p $HOME/.pki/nssdb $ cd $HOME/.pki/nssdb $ certutil -N -d sql:.
$ curl -k -o "cacert-root.crt" "http://www.cacert.org/certs/root.crt" $ curl -k -o "cacert-class3.crt" "http://www.cacert.org/certs/class3.crt" $ certutil -d sql:$HOME/.pki/nssdb -A -t TC -n "CAcert.org" -i cacert-root.crt $ certutil -d sql:$HOME/.pki/nssdb -A -t TC -n "CAcert.org Class 3" -i cacert-class3.crt
Now users may manually import a self-signed certificate.
Example 1: Using a shell script to isolate the certificate from TomatoUSB
Below is a simple script that will extract and add a certificate to the user's nssdb
:
#!/bin/sh # # usage: import-cert.sh remote.host.name [port] # REMHOST=$1 REMPORT=${2:-443} exec 6>&1 exec > $REMHOST echo | openssl s_client -connect ${REMHOST}:${REMPORT} 2>&1 |sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' certutil -d sql:$HOME/.pki/nssdb -A -t TC -n "$REMHOST" -i $REMHOST exec 1>&6 6>&-
Syntax is advertised in the commented lines.
Reference:
Example 2: Using Firefox to isolate the certificate from TomatoUSB
The firefox browser can be used to save the certificate to a file for manual import into the database.
Using firefox:
- Browse to the target URL.
- Upon seeing the "This Connection is Untrusted" warning screen, click: I understand the Risks > Add Exception...
- Click: View > Details > Export and save the certificate to a temporary location (
/tmp/easy.pem
in this example).
Now import the certificate for use in Chromium:
$ certutil -d sql:$HOME/.pki/nssdb -A -t TC -n "easy" -i /tmp/easy.pem
Reference:
Making flags persistent
You can put your flags in a chromium-flags.conf
file under $HOME/.config/
(or under $XDG_CONFIG_HOME
if you have configured that environment variable).
No special syntax is used; flags are defined as if they were written in a terminal.
- The arguments are split on whitespace and shell quoting rules apply, but no further parsing is performed.
- In case of improper quoting anywhere in the file, a fatal error is raised.
- Flags can be placed in separate lines for readability, but this is not required.
- Lines starting with a hash symbol (#) are skipped.
Below is an example chromium-flags.conf
file that defines the flags --start-maximized --incognito
:
# This line will be ignored. --start-maximized --incognito
See also
- Profile-sync-daemon - Systemd service that saves Chromium profile in tmpfs and syncs to disk
- Tmpfs - Tmpfs Filesystem in
/etc/fstab
- Official tmpfs kernel Documentation