SSID and passphrase/PSK may be truncated or be treated as broken

[inagaki83]

Hardware:

Board: ESP32 Dev Module
Core Installation version: 1.0.3
IDE name: Arduino IDE
Flash Frequency: 40MHz
PSRAM enabled: no
Upload Speed: 460800
Computer OS: Debian

Description:

1. SSID is up to 32-octet length according to the standard. But 32-octet SSID is rejected in WiFiSTA.cpp or is truncated to 31 octets in WiFiAP.cpp.
2. 64-char PSK is truncated to 63 characters (to be broken) in WiFiAP.cpp by strlcpy().
3. SoftAP with 62-char or shorter passphrases might cause "Password error" in client side (10% of board caused this issue). Filling the wifi_ap_config_t::password[64] using strncpy() resolved the issue. So it's an ESP-IDF bug and affected by some noise bytes after NUL, I guess.
4. On the HEAD, SSID or passphrase including % will cause unintentional printf formatting and will be broken in WiFiAP.cpp and WiFiSTA.cpp.

SSID and passphrase/PSK should always be copied using strncpy(), I think.

Sketch:

In the official example WiFiAccessPoint.ino, you should use...:

• 32-octet SSID.
• 64-character PSK.
• some % character in SSID and passphrase.

In the official example WiFiClient.ino, you should use...:

• 32-octet SSID.
• some % character in SSID and passphrase.

Debug Messages:

No debug messages.

[inagaki83]

strcmp is used to compare SSIDs or passphrases in WiFiAP.cpp. You should use strncmp for it in case 32-octet SSID or 64-char PSK comes.

[inagaki83]

The third problem is not fixed (once fixed and newly made!) on the current HEAD. Or is the ESP-IDF bug is fixed?

[me-no-dev]

Are you saying we should add \0 at the end of wifi_ap_config_t::password[64] up to 64 bytes?

[inagaki83]

Yes.
You should fill the space with \0 from the end of the string up to 64 bytes (if the string is shorter) or the ESP-IDF will be affected by noise bytes there, I think.

[me-no-dev]

do you have any way to confirm this? If so, we can add the fix here and notify IDF team of the issue.

[inagaki83]

I've made a test sketch but I can't reproduce the problem now.
So it doesn't have to be changed. Thank you.