tazpanel annotate README.devel @ rev 638

boot.iso: allow /dev/cdrom
author Pascal Bellard <pascal.bellard@slitaz.org>
date Wed Jan 05 15:14:01 2022 +0000 (2022-01-05)
parents 525e6519e66b
children
rev   line source
al@463 1 Various Development Notes
al@463 2 =========================
al@463 3
al@463 4 --------------------------------------------------------------------------------
al@463 5
al@463 6 network.cgi
al@463 7 -----------
al@463 8
al@463 9 Goal: allow ANY symbols in the WPA PSK (Wi-Fi password).
paul@481 10 We can find WPA PSK in all the different places, and there are different
al@463 11 restrictions to write it.
al@463 12
al@463 13 a) /etc/network.conf: SliTaz system wide networking configuration;
al@463 14 b) /etc/wpa/wpa.conf: wpa_supplicant configuration file;
al@463 15 c) html input form in the TazPanel > Network > Wireless;
al@463 16 d) saved passwords for known networks in the javascript in the same place.
al@463 17
paul@481 18 Let's see all those files/places one by one.
al@463 19
al@463 20
al@463 21 a) network.conf
al@463 22
paul@481 23 Really "network.conf" is a shell script. It contains variables definitions and
paul@481 24 is sourced into other shell scripts to define all Wi-Fi configuration variables.
paul@481 25 By default, we can see variables and their contents in the double quotes:
al@463 26
al@463 27 WIFI_KEY="mypassword"
al@463 28 There are many pitfalls if we allow ANY symbols here:
al@463 29
al@463 30 Variable expansion:
al@463 31 WIFI_KEY="123$HOME"
al@463 32 WIFI_KEY="$0$#$? *"
al@463 33
al@463 34 Command expansion:
al@463 35 WIFI_KEY="123$(echo 456)789"
al@463 36 WIFI_KEY="`rm -rf /`"
al@463 37
al@463 38 Quoting problem:
al@463 39 WIFI_KEY="abc"def'ghi"
al@463 40
paul@481 41 Seems, we'll solve the problem when escaping some symbols:
al@463 42 \ → \\
al@463 43 " → \"
al@463 44 $ → \$
al@463 45 ` → \`
al@463 46
paul@481 47 Another solution exists (and currently I stick to it): single quotes. We need not
al@463 48 escape anything but single quotes (') in the single quotes terminated string.
al@463 49 And yes, this quoting is a pain for brain:
al@463 50
al@463 51 Password: abc"def'ghi
al@463 52 String : WIFI_KEY='abc"def'"'"'ghi'
al@463 53 But it is simple work for sed command.
al@463 54
al@463 55
al@463 56 b) wpa.conf
al@463 57
paul@481 58 wpa_supplicant actually connects us to our Wi-Fi networks and it is a file
al@463 59 where we can store all our networks settings, including passwords. It is handy
al@463 60 when you have one network at home, other - at work, and another - at your
paul@481 61 friends home. Really, you shouldn't need to re-enter all these passwords again.
al@463 62
al@464 63 We can read a lot of useful information in the wpa_supplicant.conf file
al@463 64 (/etc/wpa/wpa_supplicant.conf):
al@463 65
al@463 66 # psk: WPA preshared key; 256-bit pre-shared key
al@463 67 # The key used in WPA-PSK mode can be entered either as 64 hex-digits, i.e.,
al@463 68 # 32 bytes or as an ASCII passphrase (in which case, the real PSK will be
al@463 69 # generated using the passphrase and SSID). ASCII passphrase must be between
al@463 70 # 8 and 63 characters (inclusive). ext:<name of external PSK field> format can
al@463 71 # be used to indicate that the PSK/passphrase is stored in external storage.
al@463 72 # This field is not needed, if WPA-EAP is used.
al@463 73 # Note: Separate tool, wpa_passphrase, can be used to generate 256-bit keys
paul@481 74 # from ASCII passphrase. This process uses lots of CPU and wpa_supplicant
paul@540 75 # startup and reconfiguration time can be optimized by generating the PSK
al@463 76 # only when the passphrase or SSID has actually changed.
al@463 77
al@463 78
paul@481 79 Interesting and good method to use 64 symbols "passwords", maybe we can switch to it
al@463 80 sometimes. Example of using "wpa_passphrase":
paul@481 81 Let network name be: my_wifi
paul@481 82 Let password be : abc'def"ghi
paul@481 83 Let's run utility twice - with a different quoting style:
al@463 84
al@463 85 tux@slitaz:~$ wpa_passphrase my_wifi "abc'def\"ghi"
al@463 86 network={
al@463 87 ssid="my_wifi"
al@463 88 #psk="abc'def"ghi"
al@463 89 psk=e99c121a998a0c35419b16fd56beb38d2b471fd5519518c056af933e9daf3e30
al@463 90 }
al@463 91 tux@slitaz:~$ wpa_passphrase my_wifi 'abc'"'"'def"ghi'
al@463 92 network={
al@463 93 ssid="my_wifi"
al@463 94 #psk="abc'def"ghi"
al@463 95 psk=e99c121a998a0c35419b16fd56beb38d2b471fd5519518c056af933e9daf3e30
al@463 96 }
al@463 97
paul@481 98 Here the psk are identical, so we can use this method.
al@463 99
al@463 100 But I can't find advanced info about quoting style in the wpa_supplicant
paul@481 101 configuration file. So, I ended with a little experiment. I've created a new
al@463 102 network connection in my Android smartphone and viewed my
al@463 103 /data/misc/wifi/wpa_supplicant.conf file using Root Explorer application:
al@463 104
al@463 105 network={
al@463 106 ssid="my_wifi"
al@463 107 scan_ssid=1
al@463 108 psk="abc'def"ghi"
al@463 109 key_mgmt=WPA-PSK
al@463 110 }
al@463 111
paul@481 112 Yes, we can see unpaired quotes. Really I don't know if it is right. Maybe,
paul@481 113 wpa_supplicant just reads line content between first and last quotes. Need to
paul@481 114 dig into sources... And now I will not quote psk in any manner.
al@463 115
al@463 116
al@463 117 c) network.cgi form input
al@463 118
al@463 119 Piece of html code:
al@463 120
al@463 121 <input type="password" name="password" value="$WIFI_KEY" id="password"/>
al@463 122
paul@481 123 Here we are free to use single quotes or double quotes, but we should escape them
al@463 124 in the html manner:
al@463 125 ' → &apos;
al@463 126 " → &quot;
al@463 127
al@463 128 Also, don't forget about these symbols:
al@463 129 & → &amp;
al@463 130 < → &lt;
al@463 131 > → &gt;
al@463 132
al@463 133
al@463 134 d) network.cgi javascript database
al@463 135
al@463 136 Also, we store passwords in the known networks database in the form of
paul@481 137 javascript to gain user experience without pages having to be reloaded: you can click
paul@481 138 Wi-Fi network name and the script will fill its password for you.
al@463 139
paul@540 140 Here's an example of that script on the html page:
al@463 141
al@463 142 <script type="text/javascript">
al@463 143 ajax('network.cgi?wifi_list', '1', 'wifiList');
al@463 144 networks = [
al@463 145 {ssid:"my_wifi", scan_ssid:"1", psk:"my_password", key_mgmt:"WPA-PSK",
al@463 146 priority:"1"},
al@463 147 {ssid:"your_wifi", scan_ssid:"1", key_mgmt:"NONE", auth_alg:"OPEN SHARED",
al@463 148 wep_key0:"01234567890123456789abcdef", priority:"3"}
al@463 149 ];
al@463 150 </script>
al@463 151
paul@481 152 Here we need to escape ('"&<>) symbols but in another manner slightly:
al@464 153 \ → \\
al@464 154 " → \"
al@463 155
al@463 156
al@463 157 So, what do you think about this very special password? :=D
al@463 158 a'b"c $(echo 2)=$HOME`date`\t&#x
al@463 159
al@463 160 --------------------------------------------------------------------------------