![](/media/cache/img/default_profile.jpg.50x50_q85.jpg)
Catie fork
Dependencies: SDFileSystem X_NUCLEO_IKS01A1
Fork of ATT_AWS_IoT_demo by
Diff: README.md
- Revision:
- 2:270602af41c9
- Child:
- 5:8275e4cee0d5
diff -r 29b9860f1cac -r 270602af41c9 README.md --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/README.md Thu Jul 28 23:14:10 2016 +0100 @@ -0,0 +1,85 @@ +# HTTPS File Download Example for TLS Client on mbed OS + +This application downloads a file from an HTTPS server (developer.mbed.org) and looks for a specific string in that file. + +# Getting started + +Set up your environment if you have not done so already. For instructions, refer to the [main readme](../README.md). + +## Required hardware + +This example also requires an Ethernet cable an connection to the internet additional to the hardware requirements in the [main readme](../README.md). + +## Monitoring the application + +__NOTE:__ Make sure that the Ethernet cable is plugged in correctly before running the application. + +The output in the terminal window should be similar to this: + +``` +Using Ethernet LWIP +Client IP Address is 10.2.203.43 +Connecting with developer.mbed.org +Starting the TLS handshake... +TLS connection to developer.mbed.org established +Server certificate: + cert. version : 3 + serial number : 11:21:B8:47:9B:21:6C:B1:C6:AF:BC:5D:0C:19:52:DC:D7:C3 + issuer name : C=BE, O=GlobalSign nv-sa, CN=GlobalSign Organization Validation CA - SHA256 - G2 + subject name : C=GB, ST=Cambridgeshire, L=Cambridge, O=ARM Ltd, CN=*.mbed.com + issued on : 2016-03-03 12:26:08 + expires on : 2017-04-05 10:31:02 + signed using : RSA with SHA-256 + RSA key size : 2048 bits + basic constraints : CA=false + subject alt name : *.mbed.com, mbed.org, *.mbed.org, mbed.com + key usage : Digital Signature, Key Encipherment + ext key usage : TLS Web Server Authentication, TLS Web Client Authentication +Certificate verification passed + +HTTPS: Received 439 chars from server +HTTPS: Received 200 OK status ... [OK] +HTTPS: Received 'Hello world!' status ... [OK] +HTTPS: Received message: + +HTTP/1.1 200 OK +Server: nginx/1.7.10 +Date: Wed, 20 Jul 2016 10:00:35 GMT +Content-Type: text/plain +Content-Length: 14 +Connection: keep-alive +Last-Modified: Fri, 27 Jul 2012 13:30:34 GMT +Accept-Ranges: bytes +Cache-Control: max-age=36000 +Expires: Wed, 20 Jul 2016 20:00:35 GMT +X-Upstream-L3: 172.17.0.3:80 +X-Upstream-L2: developer-sjc-indigo-1-nginx +Strict-Transport-Security: max-age=31536000; includeSubdomains + +Hello world! +``` + +## Debugging the TLS connection + +To print out more debug information about the TLS connection, edit the file `main.cpp` and change the definition of `DEBUG_LEVEL` (near the top of the file) from 0 to a positive number: + +* Level 1 only prints non-zero return codes from SSL functions and information about the full certificate chain being verified. + +* Level 2 prints more information about internal state updates. + +* Level 3 is intermediate. + +* Level 4 (the maximum) includes full binary dumps of the packets. + + +The TLS connection can fail with an error similar to: + + mbedtls_ssl_write() failed: -0x2700 (-9984): X509 - Certificate verification failed, e.g. CRL, CA or signature check failed + Failed to fetch /media/uploads/mbed_official/hello.txt from developer.mbed.org:443 + +This probably means you need to update the contents of the `SSL_CA_PEM` constant (this can happen if you modify `HTTPS_SERVER_NAME`, or when `developer.mbed.org` switches to a new CA when updating its certificate). + +Another possible reason for this error is a proxy providing a different certificate. Proxies can be used in some network configurations or for performing man-in-the-middle attacks. If you choose to ignore this error and proceed with the connection anyway, you can change the definition of `UNSAFE` near the top of the file from 0 to 1. + +**Warning:** this removes all security against a possible active attacker, so use at your own risk or for debugging only! +