Empty URL query name cause ESP32 to crash

[rev1204]

Platform

ESP32

IDE / Tooling

pioarduino

What happened?

Getting the URL arguments from normal URL like this works:

192.168.4.1/?n=v

But if URL has an empty key:

192.168.4.1/?=v

It crash the ESP32.
I know it's not a valid URL, but it should not crash. Tried with latest v3.11.2. Last version without crash that I know is v3.6.2.

Stack Trace

Guru Meditation Error: Core 1 panic'ed (LoadProhibited). Exception was unhandled.

Core 1 register dump:
PC : 0x400dc7b1 PS : 0x00060330 A0 : 0x800dc7e2 A1 : 0x3ffd5290
A2 : 0x3ffd52dc A3 : 0x00000010 A4 : 0x00000001 A5 : 0x3ffd15f8
A6 : 0x3ffd54cc A7 : 0x3ffc3fd8 A8 : 0x800dc4b0 A9 : 0x3ffd5270
A10 : 0x00000010 A11 : 0x00000000 A12 : 0x00000011 A13 : 0x3ffd543c
A14 : 0x3ffc3fd8 A15 : 0x3ffd542c SAR : 0x00000010 EXCCAUSE: 0x0000001c
EXCVADDR: 0x0000001f LBEG : 0x40089099 LEND : 0x400890bd LCOUNT : 0x800dca25

Backtrace: 0x400dc7ae:0x3ffd5290 0x400dc7df:0x3ffd52b0 0x400db726:0x3ffd52d0 0x400d6cce:0x3ffd5330 0x40166837:0x3ffd5370 0x400d6956:0x3ffd5390 0x400d6ac5:0x3ffd53b0 0x400d6d9e:0x3ffd5420 0x400d6956:0x3ffd5460 0x400d6ac5:0x3ffd5480 0x400d6f1b:0x3ffd54f0 0x400d869b:0x3ffd5530 0x400d958c:0x3ffd5570 0x400d96e9:0x3ffd5590 0x400d4579:0x3ffd55b0 0x400d4bf9:0x3ffd55e0 0x400d4d25:0x3ffd5600 0x4008c68d:0x3ffd5630

ELF file SHA256: a7b99706e

Rebooting...

Minimal Reproductible Example (MRE)

MRE:

#include <Arduino.h>
#include <WiFi.h>
#include <ESPAsyncWebServer.h>

AsyncWebServer server(80);

void setup() {
  delay(1000);
  Serial.begin(2000000);
  Serial.println("\nSTART");

  WiFi.mode(WIFI_AP);
  WiFi.softAP("test", "88888888");
  
  server.on("/", HTTP_GET, [](AsyncWebServerRequest *request){
    String v = request->arg(0u);
    Serial.println(v);
    request->send(200, "text/plain", "OK");
  });
  server.begin();
}

void loop() {}

I confirm that:

• I have read the documentation.
• I have searched for similar discussions.
• I have searched for similar issues.
• I have looked at the examples.
• I have upgraded to the lasted version of ESPAsyncWebServer (and AsyncTCP for ESP32).

[mathieucarbou]

Thank you for the bug report, I will look at this this weekend but if you want to send a PR also you are more than welcome!