Ephemeral mode

[fanglingsu]

Allow to run vimb in ephemeral mode to not store sensitive data in filesystem and to not allow websites to store data in the browser. It makes no sense to allow to switch an always running vimb instance into ephemeral mode. So it's enought to give this by command line option at the time --ephemeral.

affected files

Following files under $XDG_CONFIG_HOME/vimb should be used read only when
ephemeral mode is on.

• closed
• command
• coonied.db - this file must not be used because we want the cookies to be
  stored in webkit runtime memory only.
• history
• search

Only the queue and bookmark files should be allowed to be written.

do write operations in memory

To provide also completions for url, search queries and commands, it would be great to allow to store those data in memory instead of the files and to merge thems into the result like they where read from the files.

references

webkit_web_context_new_ephemeral

[cdlscpmv]

Good proposal!

Perhaps, creating a few temporary files in /tmp for every ephemeral instance is one way to go. They can be merged on the fly with the rest of the profile data sitting in ~/.config. The problem is that vimb should somehow detect when the last window assosiated with the instance is closed and then remove the temporary files.

Also, I think a new "closed" file should be created for a new ephemeral instance. This would allow reopening a previously closed window but only if that window had been opened in the ephemeral instance.

[fanglingsu]

I don't like the idea to write files in ephemeral mode. OK, ite would be easy to do but on multiuser systems they might leak data. And in case vimb crashes they would be left on disc.

[cdlscpmv]

The function shm_open(3) stores files in memory on Linux (I guess, the same is true for BSDs also) which implies that they will live till the next reboot if left undeleted. They can be swapped out to disk though, but this also applies to the memory used by WebKit itself.

On Linux the temporary files reside in /dev/shm. By setting appropriate permissions on them the problem of data leaks in multiuser systems can be mitigated.

[fanglingsu]

I've implemented Ephemeral/Incognito mode and I'l try it out on my daily work.

[cdlscpmv]

I've just tested it, and it seems to work. Unfortunately, the browsing history is not preserved when opening a new window with :tabopen (I don't know if cookies are). I don't think it's a big deal, since solving the above issues requires either creating new files or having some sort of IPC between the incognito instances.

[fanglingsu]

@cdlscpmv Cookies are also not preserved on opening an new window. But I think this is acceptable for a one window browser at the time.

[fanglingsu]

I've merge the branch into master.