Security issue with .desktop files revisited

[Francois Gouget]

Mike Hearn wrote:
[...]
> right now +x on such a file is meaningless anyway.

One more thing, the above remark is in fact pretty insightful: normal 
desktop files are not programs, neither of the shell or of the ELF kind. 
They are data files. Running them does not work. Only malicious desktop 
files can actually be run when marked +x.

Marking a large number of non-runnable data files as executables for 
whatever reason cannot be a good idea:
  * When a user sees a file called 'foo.desktop' that is executable then 
he rightly expects './foo.desktop' to do something meaningful. Marking 
desktop files +x breaks this expectation which in the best case is going 
to lead to lots of support questions.
  * It also leds to confusion as to exactly what the +x bit means.
  * It would be very much akin to marking jpeg files as executable to 
prevent some of them from exploiting buffer overflows in graphics programs.

Now if desktop files were to start with '#!/usr/bin/whatever', then 
making the trusted ones executable could make sense.

-- 
Francois Gouget
fgouget at codeweavers.com