Can't connect to Wi-Fi due to unsupported character in SSID

[IanDavies]

Hi there, after refreshing my Pi3 emonBase to emonSD-24Jul20 and emoncms then updating to 10.6.9 via ethernet, I want to switch back to Wi-Fi. However, when I select my SSID and enter the password, I am getting an error referring to a neighbours SSID which appears in the list of 4 SSID’s, even though I am not trying to use it:

EmonCMS Error

Message: Error: Syntax error, unrecognized expression: .psk[ssid=‘Rhys’. Get off’]
Route: Lib/jquery-1.11.3.min.js
Line: 2
Column: 12748

I assume it is because the neighbours SSID has a single apostrophe in its name, as visible in this screenshot

This error is preventing me from selecting my own Wi-Fi SSID.

Apart from trying to shield the Pi so it cannot see the offending SSID long enough to get select my SSID, any other suggestions on dealing with this?

Thanks

Ian

[Robert.Wall]

This looks like one for @TrystanLea - if nothing else, I’d be worried that it points to a weakness that’s inviting a buffer overflow/cross-site scripting attack.

If you can get into the Pi via SSH, or you can take the SD card out and edit the file elsewhere, then this might help:

Raspberry Pi Documentation - Configuration

(where you’re adding to the wpa_supplicant.conf file).

[djh (Dave Howorth)]

I don’t know much about SSID syntax so I did some searches and it appears [1] that an SSID can contain an arbitrary value up to 32 octets long. It can also choose to restrict itself to a UTF-8 encoded value also limited to 32 octets. But a single quote would be legal in either case, so it sounds like the issue might be a bug in the software that reports the error?

If the software is jquery-1.11.3 then it seems that is rather old, so a first step might be updating to a [near] current version?

It does seem to me that a developer will be needed to fix the problem.

[1] Service set (802.11 network) - Wikipedia

[Robert.Wall]

@djh

it sounds like the issue might be a bug in the software that reports the error

That was exactly my thinking when I wrote

@Robert.Wall

This looks like one for @TrystanLea,

who is the developer. But it seems he hasn’t seen this yet.

[borpin (Brian Orpin)]

This is a long standing ‘feature’ IIRC.

[Robert.Wall]

Your memory is better than mine

Emon base WIFI unable to connect. SSID not accepted?,syntax error

Hi folks. I have a Base pi , ethernet cable connected, SSH into the PI is fine, log into local emonpi is fine, the problem is the emonpi local page will not accept the SSID of the ethernet modem namely WiFi-2.4-D439 . The base pi has worked previously on a normal ethernet network and connected sucessfully. SSID and password are correct, i manually entered the SSID and Password in the etc network interfaces. Syntax error on the web console EmonCms is XML Parsing Error: syntax error Location: h…

and

Emoncms WiFi Module - special characters not supported in network password?

Hi, I received my EmonPi today, and I couldn’t get it connected to my WiFi network. It’s working now, but it appears that the problem was that the EmonPi didn’t recognise my network password because it contained a “+” symbol. If you enter a password that contains a “+”, and then click the eye icon to show the password, the + is replaced with a space. This might just be a quirk of the user interface, but I couldn’t get the EmonPi to connect to my wifi network until I changed my network password…

where it appears that @glyn.hudson is still working on a fix, if the final post is to be believed:

@glyn.hudson

Ok, thanks. I’ve re-opened the issue

[TrystanLea]

I can see what’s causing this, we fixed one issue with special characters but obviously not this one. Looking at this now and testing here it looks like I’m going to need to change the implementation of the WiFi interface quite a bit to get it to work… will update further soon.

[IanDavies]

Hi Robert, Thanks for this suggestion, it worked. I should have thought of this myself, so thanks for pointing me in the right direction.
Regards
Ian

[lachie (Lachie Murray)]

I raised this PR a while ago to fix an issue with unsupported characters in WiFi passwords: Use fwrite instead of exec to ensure single quotes can be handled in PSK by lachiemurray · Pull Request #36 · emoncms/wifi · GitHub. I’ve not tested but it’s possible it solves the problem for SSIDs as well

[TrystanLea]

Hello @lachie sorry to miss your pull request on the WiFi module, it looks good, will test and merge assuming all goes well.

[lachie (Lachie Murray)]

@TrystanLea no worries, thank you!