tazpanel view README.devel @ rev 469

Typo in hardware.cgi
author Pascal Bellard <pascal.bellard@slitaz.org>
date Mon Apr 27 00:16:35 2015 +0200 (2015-04-27)
parents 7ca14d55e705
children 525e6519e66b
line source
1 Various Development Notes
2 =========================
3
4 --------------------------------------------------------------------------------
5
6 network.cgi
7 -----------
8
9 Goal: allow ANY symbols in the WPA PSK (Wi-Fi password).
10 We can find WPA PSK in the different places, and there are different
11 restrictions to write it.
12
13 a) /etc/network.conf: SliTaz system wide networking configuration;
14 b) /etc/wpa/wpa.conf: wpa_supplicant configuration file;
15 c) html input form in the TazPanel > Network > Wireless;
16 d) saved passwords for known networks in the javascript in the same place.
17
18 Let's see all that files/places one by one.
19
20
21 a) network.conf
22
23 Really "network.conf" is a shell script. It contains variables definitions, and
24 it sourced into other shell scripts to define all Wi-Fi configuration variables.
25 By default, we can see variable and its content in the double quotes:
26
27 WIFI_KEY="mypassword"
28
29 There are many pitfalls if we allow ANY symbols here:
30
31 Variable expansion:
32 WIFI_KEY="123$HOME"
33 WIFI_KEY="$0$#$? *"
34
35 Command expansion:
36 WIFI_KEY="123$(echo 456)789"
37 WIFI_KEY="`rm -rf /`"
38
39 Quoting problem:
40 WIFI_KEY="abc"def'ghi"
41
42 Seems, we'll solve the problem when escape some symbols:
43 \ → \\
44 " → \"
45 $ → \$
46 ` → \`
47
48 Another solution exists (and currently I stick to it): single quotes. We need no
49 escape anything but single quotes (') in the single quotes terminated string.
50 And yes, this quoting is a pain for brain:
51
52 Password: abc"def'ghi
53 String : WIFI_KEY='abc"def'"'"'ghi'
54 But it is simple work for sed command.
55
56
57 b) wpa.conf
58
59 wpa_supplicant actually connects us to our Wi-Fi networks, and it is a file
60 where we can store all our networks settings, including passwords. It is handy
61 when you have one network at home, other - at work, and another - at your
62 friends home. Really, you shouldn't to re-enter all these passwords again.
63
64 We can read a lot of useful information in the wpa_supplicant.conf file
65 (/etc/wpa/wpa_supplicant.conf):
66
67 # psk: WPA preshared key; 256-bit pre-shared key
68 # The key used in WPA-PSK mode can be entered either as 64 hex-digits, i.e.,
69 # 32 bytes or as an ASCII passphrase (in which case, the real PSK will be
70 # generated using the passphrase and SSID). ASCII passphrase must be between
71 # 8 and 63 characters (inclusive). ext:<name of external PSK field> format can
72 # be used to indicate that the PSK/passphrase is stored in external storage.
73 # This field is not needed, if WPA-EAP is used.
74 # Note: Separate tool, wpa_passphrase, can be used to generate 256-bit keys
75 # from ASCII passphrase. This process uses lot of CPU and wpa_supplicant
76 # startup and reconfiguration time can be optimized by generating the PSK only
77 # only when the passphrase or SSID has actually changed.
78
79
80 Interesting and good method to use 64 symbols "passwords", maybe we switch to it
81 sometimes. Example of using "wpa_passphrase":
82 Let network name is: my_wifi
83 Let password is : abc'def"ghi
84 Let's run utility twice - with different quoting style:
85
86 tux@slitaz:~$ wpa_passphrase my_wifi "abc'def\"ghi"
87 network={
88 ssid="my_wifi"
89 #psk="abc'def"ghi"
90 psk=e99c121a998a0c35419b16fd56beb38d2b471fd5519518c056af933e9daf3e30
91 }
92 tux@slitaz:~$ wpa_passphrase my_wifi 'abc'"'"'def"ghi'
93 network={
94 ssid="my_wifi"
95 #psk="abc'def"ghi"
96 psk=e99c121a998a0c35419b16fd56beb38d2b471fd5519518c056af933e9daf3e30
97 }
98
99 Here psk are identical, so we can use this method.
100
101 But I can't find advanced info about quoting style in the wpa_supplicant
102 configuration file. So, I ended with little experiment. I've created new
103 network connection in my Android smartphone and viewed my
104 /data/misc/wifi/wpa_supplicant.conf file using Root Explorer application:
105
106 network={
107 ssid="my_wifi"
108 scan_ssid=1
109 psk="abc'def"ghi"
110 key_mgmt=WPA-PSK
111 }
112
113 Yes, we can see unpaired quotes. Really don't know is it right. Maybe,
114 wpa_supplicant just readed line content between first and last quotes. Need to
115 dig into sources... And now I not quote psk in any manner.
116
117
118 c) network.cgi form input
119
120 Piece of html code:
121
122 <input type="password" name="password" value="$WIFI_KEY" id="password"/>
123
124 Here we free to use single quotes or double quotes, but we should escape them
125 in the html manner:
126 ' → &apos;
127 " → &quot;
128
129 Also, don't forget about these symbols:
130 & → &amp;
131 < → &lt;
132 > → &gt;
133
134
135 d) network.cgi javascript database
136
137 Also, we store passwords in the known networks database in the form of
138 javascript to gain user experience without page to be reloaded: you can click
139 Wi-Fi network name and script will fill its password for you.
140
141 Here example of that script on the html page:
142
143 <script type="text/javascript">
144 ajax('network.cgi?wifi_list', '1', 'wifiList');
145 networks = [
146 {ssid:"my_wifi", scan_ssid:"1", psk:"my_password", key_mgmt:"WPA-PSK",
147 priority:"1"},
148 {ssid:"your_wifi", scan_ssid:"1", key_mgmt:"NONE", auth_alg:"OPEN SHARED",
149 wep_key0:"01234567890123456789abcdef", priority:"3"}
150 ];
151 </script>
152
153 Here we need to escape ('"&<>) symbols but in the slightly another manner:
154 \ → \\
155 " → \"
156
157
158 So, what do you think about this very special password? :=D
159 a'b"c $(echo 2)=$HOME`date`\t&#x
160
161 --------------------------------------------------------------------------------