unsafe-browser 6.52 KB
Newer Older
1
#!/bin/sh
2

3
4
set -e

Tails developers's avatar
Tails developers committed
5
CMD=$(basename ${0})
6
LOCK=/var/lock/${CMD}
Tails developers's avatar
Tails developers committed
7
8

. gettext.sh
9
TEXTDOMAIN="${CMD}"
Tails developers's avatar
Tails developers committed
10
11
export TEXTDOMAIN

12
13
SQUASH=/live/image/live/filesystem.squashfs
ROFS=/live/rofs
14
15
16
CONF_DIR=/var/lib/unsafe-browser
COW=${CONF_DIR}/cow
CHROOT=${CONF_DIR}/chroot
17
18
19
20
21
22
CLEARNET_USER=clearnet
OFFENDING_ADDONS="xul-ext-foxyproxy-standard xul-ext-torbutton"
TOR_DIR=/var/lib/tor
TOR_DESCRIPTORS=${TOR_DIR}/cached-descriptors
TOR_WORKING=""

23
24
25
26
27
28
29
30
WARNING_PAGE='/usr/share/doc/tails/website/misc/unsafe_browser_warning'
LANG_CODE="$(echo ${LANG} | head -c 2)"
if [ -r "${WARNING_PAGE}.${LANG_CODE}.html" ]; then
   START_PAGE="${WARNING_PAGE}.${LANG_CODE}.html"
else
   START_PAGE="${WARNING_PAGE}.en.html"
fi

31
cleanup () {
32
33
34
    # Break down the chroot and kill all of its processes
    local counter=0
    local ret=0
35
    while [ "${counter}" -le 10 ] && \
Tails developers's avatar
Tails developers committed
36
        pgrep -u ${CLEARNET_USER} 1>/dev/null 2>&1; do
37
        pkill -u ${CLEARNET_USER} 1>/dev/null 2>&1
38
        ret=${?}
39
        sleep 1
40
        counter=$((${counter}+1))
41
    done
42
43
    [ ${ret} -eq 0 ] || pkill -9 -u ${CLEARNET_USER} 1>/dev/null 2>&1
    for mnt in ${CHROOT}/dev ${CHROOT}/proc ${CHROOT} ${COW} ${ROFS}; do
44
        counter=0
45
46
        while [ "${counter}" -le 10 ] && mountpoint -q ${mnt} 2>/dev/null; do
            umount ${mnt} 2>/dev/null
47
            sleep 1
48
            counter=$((${counter}+1))
49
50
        done
    done
51
    rmdir ${ROFS} ${COW} ${CHROOT} 2>/dev/null
52
53
54
}

error () {
Tails developers's avatar
Tails developers committed
55
    local cli_text="${CMD}: `gettext \"error\"`: ${@}"
Tails developers's avatar
Tails developers committed
56
    local dialog_text="${@}
57

Tails developers's avatar
Tails developers committed
58
`gettext \"Unsafe Browser will exit now.\"`"
59
    echo "${cli_text}" >&2
60
    sudo -u ${SUDO_USER} zenity --error --title "" --text "${dialog_text}"
61
62
63
64
    exit 1
}

warning () {
65
    local text="${@}"
Tails developers's avatar
Tails developers committed
66
    echo "${CMD}: `gettext \"warning\"`: ${text}" >&2
67
    sudo -u ${SUDO_USER} zenity --warning --title "" --text "${text}"
68
69
}

70
71
verify_start () {
    # Make sure the user really wants to start the browser
Tails developers's avatar
Tails developers committed
72
    local dialog_msg="<b>`gettext \"Do you really want to launch the Unsafe Browser?\"`</b>
73

Tails developers's avatar
Tails developers committed
74
`gettext \"Network activity within the Unsafe Browser is <b>not anonymous</b>. Only use the Unsafe Browser if necessary, for example if you have to login or register to activate your Internet connection.\"`"
75
76
77
78
79
80
    local launch="`gettext \"_Launch\"`"
    local exit="`gettext \"_Exit\"`"
    # Since zenity can't set the default button to cancel, we switch the
    # labels and interpret the return value as its negation.
    if sudo -u ${SUDO_USER} zenity --question --title "" --ok-label "${exit}" \
       --cancel-label "${launch}" --text "${dialog_msg}"; then
81
82
83
        exit 0
    fi
}
84

85
86
87
88
setup_chroot () {
    # Setup a chroot on an aufs "fork" of the filesystem.
    # FIXME: When LXC matures to the point where it becomes a viable option
    # for creating isolated jails, the chroot can be used as its rootfs.
89
90
    echo "* Setting up chroot"

91
92
93
    trap cleanup INT
    trap cleanup EXIT

94
95
96
97
98
    mkdir -p ${ROFS} ${COW} ${CHROOT} && \
    mount -t squashfs -o loop ${SQUASH} ${ROFS} && \
    mount -t tmpfs tmpfs ${COW} && \
    mount -t aufs -o noatime,noxino,dirs=${COW}=rw:${ROFS}=rr+wh aufs ${CHROOT} && \
    mount -t proc proc ${CHROOT}/proc && \
Tails developers's avatar
Tails developers committed
99
100
    mount --bind /dev ${CHROOT}/dev || \
    error "`gettext \"Failed to setup chroot.\"`"
101
102
103
}

configure_chroot () {
104
105
    echo "* Configuring chroot"

106
107
    # Set the chroot's DNS servers to those obtained through DHCP
    rm -f ${CHROOT}/etc/resolv.conf
108
    for NS in ${IP4_NAMESERVERS}; do
109
110
111
112
113
        echo "nameserver ${NS}" >> ${CHROOT}/etc/resolv.conf
    done
    chmod a+r ${CHROOT}/etc/resolv.conf

    # Disable problematic Iceweasel addons and proxying in the chroot
114
    chroot ${CHROOT} apt-get remove --yes ${OFFENDING_ADDONS}
115
116
117
118
    sed -i '/^pref("network.proxy.type",/d' \
        ${CHROOT}/etc/iceweasel/pref/iceweasel.js
    echo 'pref("network.proxy.type", 0);' >> \
        ${CHROOT}/etc/iceweasel/pref/iceweasel.js
119

Tails developers's avatar
Tails developers committed
120
    # Set a scary theme (except if we're using Windows camouflage)
121
    if grep -qwv winxp /proc/cmdline; then
Tails developers's avatar
Bugfix.  
Tails developers committed
122
        cat >> ${CHROOT}/etc/iceweasel/profile/user.js <<EOF
123
user_pref("lightweightThemes.isThemeSelected", true);
124
125
user_pref("lightweightThemes.usedThemes", "[{\"id\":\"1\",\"name\":\"Unsafe Browser\",\"headerURL\":\"file:///usr/share/pixmaps/red_dot.png\",\"footerURL\":\"file:///usr/share/pixmaps/red_dot.png\",\"textcolor\":\"#FFFF00\",\"accentcolor\":\"#CC0000\",\"updateDate\":0,\"installDate\":0}]");
EOF
126
    fi
127
128
129
130

    # Set start page to something that explains what's going on
    echo 'user_pref("browser.startup.homepage", "'${START_PAGE}'");' >> \
        ${CHROOT}/etc/iceweasel/profile/user.js
131
132
133
134
}

start_browser_in_chroot () {
    # Start Iceweasel in the chroot
135
136
    echo "* Starting Unsafe Browser"

137
    sudo -u ${SUDO_USER} xhost +SI:localuser:${CLEARNET_USER} 2>/dev/null
138
    chroot ${CHROOT} sudo -u ${CLEARNET_USER} iceweasel -DISPLAY=:0.0
139
    sudo -u ${SUDO_USER} xhost -SI:localuser:${CLEARNET_USER} 2>/dev/null
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
}

tor_is_working() {
    # FIXME: the approach is stolen from is_tor_working() in the 20-time
    # NM hook -- we should move things like this to a shell script library
    # FIXME: how to determine this reliably? this approach doesn't work
    # if $TOR_DIR is persistent.
    [ -e $TOR_DESCRIPTORS ]
}

maybe_restart_tor () {
    # Restart Tor if it's not working (a captive portal may have prevented
    # Tor from bootstrapping, and a restart is the fastest way to get
    # wheels turning)
    if ! tor_is_working; then
155
156
        echo "* Restarting Tor"
        if ! service tor restart; then
157
158
159
160
161
            error "`gettext \"Failed to restart Tor.\"`"
        fi
        local counter=0
        until [ "${counter}" -ge 10 ] || nc -z localhost 9051 2>/dev/null; do
            sleep 1
162
            counter=$((${counter}+1))
163
        done
164
        /etc/NetworkManager/dispatcher.d/60-vidalia.sh clearnet up 2>/dev/null
165
166
    fi
}
167

168
169
170
171
172
173
# Prevent multiple instances of the script.
exec 9>${LOCK}
if ! flock -x -n 9; then
    error "`gettext \"Another Unsafe Browser is currently running, or being cleaned up. Please retry in a while.\"`"
fi

174
# Get the DNS servers that was obtained from NetworkManager, if any...
175
176
177
178
179
180
181
182
NM_ENV=/var/lib/NetworkManager/env
if [ -r "${NM_ENV}" ]; then
    . ${NM_ENV}
fi
# ... otherwise fail.
# FIXME: Or would it make sense to fallback to Google's DNS or OpenDNS?
# Some stupid captive portals may allow DNS to any host, but chances are
# that only the portal's DNS would forward to the login page.
183
if [ -z "${IP4_NAMESERVERS}" ]; then
Tails developers's avatar
Tails developers committed
184
    error "`gettext \"No DNS server was obtained through DHCP or manually configured in NetworkManager.\"`"
185
186
fi

187
188
189
190
191
verify_start
setup_chroot
configure_chroot
start_browser_in_chroot
maybe_restart_tor
192
193

exit 0