[Tails-dev] A quick look at uwt

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Autor: intrigeri
Data:  
Para: adrelanos
CC: tails-dev
Assunto: [Tails-dev] A quick look at uwt
Hi!

it seems we'll need something similar to uwt to implement some of the
Tails stream separation design (I'm thinking of Claws Mail,
specifically), so I had a quick look. Here are a few remarks.

Predictable filename in world-writable directory => welcome to
symlink attacks:

        TORSOCKS_CONF_FILE="/tmp/$(whoami)_torsocks_temp"


Also, the use of a per-user unique filename is prone to race-conditions.

If one of -i, -p and -t is not passed, uwt happily creates
a non-functional TORSOCKS_CONF_FILE and passes it to torsocks,
who is the one who eventually complains. This is a bit confusing.

Buggy handling of wrapped commands whose arguments contain spaces (is
going through getopt necessary for the wrapped command at all?):

    $ gpg --recv-keys 2861A790
    $ gpg --list-keys "Micah Anderson"                                      
    pub   4096R/2861A790 2009-05-08 [expires: 2013-05-02]
    uid                  Micah Anderson <micah@???>
    uid                  Micah Anderson <micah@???>
    sub   4096R/D40ED62E 2009-05-08 [expires: 2013-05-03]
    sub   4096R/B61CAE53 2009-05-08
    $ uwt -i 127.0.0.1 -p 9050 -t 5 -c 'gpg --list-keys "Micah Anderson"' 
    gpg: error reading key: public key not found


Confusing message (actual behavior looks good, though):

    echo "UWT_LOCALHOST: $UWT_LOCALHOST NOT using torsocks."
    echo "exec torsocks \"$@\""


Über-bold (and probably fragile) parsing of wrapped command -- I find
this to be a bit scary, as it silently assumes every occurrence of
these strings in a wrapped command line means that the user wants to
connect to localhost, which might not be the case:

    case "$*" in
          *127.0.0.1*)
          *localhost*)


Thank you for writing uwt.

Cheers,
--
intrigeri
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