SSL socket with X.509 certificate fails for some URLs

[sharmavishnu]

Details about Problem

Tried running SSL client sample from the repo. Utilized WiFiAdapter class to connect to WiFi access point, wait for IP address assignment and wait for datetime update. After that, tried to connect using SSL socket sample. The results are:

1. AuthenticateAsClient succeeds for both www.howsmyssl.com and global-root-ca.chain-demos.digicert.com.
2. Socket write succeeds for both the domains
3. Socket read always returns 0 for www.howsmyssl.com and hangs for global-root-ca.chain-demos.digicert.com

nanoFramework area: System.Net library

VS version: 2017, V 15.9.10

VS extension version: 1.0.3.92

Target: ESP32 DevKitC

Firmware image version: 1.0.4-preview.415

Device capabilities output:
Solution Build Info: 1.0.4.415, nanoFramework running ESP32 built with IDF v3.1

AppDomains:

Assemblies:
Esp32Tests, 1.0.0.0
nanoFramework.Networking.Sntp, 1.0.4.3
Windows.Devices.Gpio, 1.1.0.0
Windows.Devices.Wifi, 1.0.6.0
System.Net, 1.0.6.0
mscorlib, 1.1.1.7
nanoFramework.Runtime.Events, 1.0.5.0
nanoFramework.Runtime.Native, 1.0.4.4
System.Net.Http, 1.0.5.0

Native Assemblies:
mscorlib v1.1.1.7, checksum 0x7CCFBEC1
nanoFramework.Runtime.Native v1.0.4.4, checksum 0xFE14C7A7
nanoFramework.Hardware.Esp32 v1.0.6.0, checksum 0xF8079179
nanoFramework.Networking.Sntp v1.0.4.3, checksum 0x733B4551
nanoFramework.Runtime.Events v1.0.5.0, checksum 0xBFF88292
EventSink v1.0.0.0, checksum 0xF32F4C3E
System.Math v1.0.4.3, checksum 0x4BDCF00F
System.Net v1.0.6.0, checksum 0x808BAB84
Windows.Devices.Adc v1.1.3.1, checksum 0xE5D11571
Windows.Devices.Gpio v1.1.0.0, checksum 0xB1F30A6A
Windows.Devices.I2c v1.1.3.1, checksum 0xA44C698B
Windows.Devices.Pwm v1.1.3.1, checksum 0x75280B26
Windows.Devices.SerialCommunication v1.1.0.0, checksum 0xA8A5A0E0
Windows.Devices.Spi v1.1.3.0, checksum 0x083DBB79
Windows.Devices.Wifi v1.0.6.0, checksum 0x1B4DDB17
Windows.Storage v1.0.0.0, checksum 0x3BE02CF0

Worked before? If so, with which nanoFramework image version: Not sure. I'm trying for the first time.

Detailed repro steps so we can see the same problem

1. Just run the SSL Client sample

Other suggested things

The NetworkHelper class does not ensure WiFi connection gets established. So used the WiFiAdapter class to connect to the access point and then test the SSL certificates.

[josesimoes]

Fixed by switching to mbedTLS provider.