[pre-sve]TC-CNET-4.4 Bad response

[chrisbeach59]

Expected a list of networks got:
[1655486825.864859][41820:41825] CHIP:DMG: Received Command Response Data, Endpoint=0 Cluster=0x0000_0031 Command=0x0000_0001
[1655486825.864954][41820:41825] CHIP:TOO: Endpoint: 0 Cluster: 0x0000_0031 Command 0x0000_0001
[1655486825.865146][41820:41825] CHIP:TOO: ScanNetworksResponse: {
[1655486825.865242][41820:41825] CHIP:TOO: networkingStatus: 0
[1655486825.865359][41820:41825] CHIP:TOO: wiFiScanResults: 7 entries
[1655486825.865439][41820:41825] CHIP:TOO: [1]: {
[1655486825.865489][41820:41825] CHIP:TOO: Security: 0
[1655486825.866616][41820:41825] CHIP:TOO: Struct truncated due to invalid value for 'Ssid'
[1655486825.866680][41820:41825] CHIP:TOO: }

[bzbarsky-apple]

@chrisbeach59 What server app is running? On what platform? What SHAs are being used? What was the actual payload (logged just above the part you're quoting)? Please attach (not paste) the full log.

[chrisbeach59]

SHA 1e3f120
I am running my thermostaat app on the Ameba/Resideo pllatform
Log file attached
TC-CNET-4-4.log

[bzbarsky-apple]

Thanks, that is very helpful. So the TLV dump shows the SSID values as empty byte strings. TLVReader::Get(ByteSpan &) will return a ByteSpan whose data() is null and length is 0 in that situatuon.

The chip-tool code for logging a byte string does BytesToUppercaseHexString which calls BytesToHex. BytesToHex does:

    if ((src_bytes == nullptr) || (dest_hex == nullptr))
    {
        return CHIP_ERROR_INVALID_ARGUMENT;
    }

which will fail out if src_bytes is null, even if src_size == 0.

We could fix this either in chip-tool (by not calling BytesToHex with the empty buffer), or in BytesToHex, by having it handle null + 0-length correctly....

[bzbarsky-apple]

I guess BytesToHex does document that the buffer must not be null... @tcarmelveilleux would you prefer we allow null + 0-size here, or just fix this caller?

[tcarmelveilleux]

Let's handle null + 0-length correctly

[woody-apple]

Cert Blocker Review: Assigning to @bzbarsky-apple