DISCONTINUATION OF PROJECT
This project will no longer be maintained by Intel.
Intel has ceased development and contributions including, but not limited to, maintenance, bug fixes, new releases, or updates, to this project.
Intel no longer accepts patches to this project.
If you have an ongoing need to use this project, are interested in independently developing it, or would like to maintain patches for the open source software community, please create your own fork of this project.
Contact: webadmin@linux.intel.com
This code sample demonstrates the procedures that must be followed when performing Remote Attestation for an Intel SGX enclave when using EPID attestations. The code sample includes both a sample ISV (independent software vendor) client (and its enclave) and ISV remote attestation server. It has been tested on the following platforms:
Linux
*Microsoft Windows**
For complete information on remote attestation, see the white paper on Intel's Developer Zone.
For more information on developing applications with Intel SGX, visit the Intel SGX landing zone.
See the full release history.
Release on 6/25/2020.
Default to version 4 of the Attestation API.
Remove references to the PSE in Linux builds.
Except as otherwise noted, source code is made available under the Intel Sample Source Code license. See the LICENSE file for terms.
For simplicity, the client and server are packaged and built together. In a real-world environment, these would be separate builds.
The service provider's remote attestation server does not require Intel SGX hardware or software to run. The server in this code sample requires the Intel SGX SDK header files in order to simplify the code and build process, but this is not strictly necessary.
Obtain a subscription key for the Intel SGX Attestation Service Utilizing Enhanced Privacy ID (EPID)
Ensure that you have one of the following operating systems:
Ensure that you have built and installed the Intel SGX packages:
Run the following commands to install the required packages to build the RA code sample (this assumes you have installed the dependencies for the Intel SGX SDK and PSW package)
$ yum install libcurl-develRun the following command to get your system's OpenSSL version. It must be at least 1.1.0:
$ openssl version--prefix and --openssldir should be set when building OpenSSL 1.1.0). For example:$ wget https://www.openssl.org/source/openssl-1.1.0i.tar.gz
$ tar xf openssl-1.1.0i.tar.gz
$ cd openssl-1.1.0i
$ ./config --prefix=/opt/openssl/1.1.0i --openssldir=/opt/openssl/1.1.0i
$ make
$ sudo make installFirst, prepare the build system (GNU* automake and autoconf) by running bootstrap, and then configure the software package using the configure command. You'll need to specify the location of OpenSSL 1.1.0. See the build notes section for additional options to configure.
$ ./bootstrap
$ ./configure --with-openssldir=/opt/openssl/1.1.0i
$ makeAs this is a code sample and not a production application, 'make install' is not implemented.
Both make clean and make distclean are supported.
The service provider sample supports two user agents on Linux for communicating with the Intel Attestation Server (IAS): libcurl and wget.
The wget agent runs wget via execvp(2) to GET and POST data to IAS.
The libcurl agent does not depend on external commands. Pre-packaged distributions of libcurl are typically built against OpenSSL, GnuTLS, or NSS.
libcurl may be built against your local distribution's OpenSSL package (which is 1.0.x for the supported OS's). If so, you will receive a warning message at link time which can be ignored. Only libcrypto is required from the OpenSSL 1.1.0 build and it will not conflict with libcurl's OpenSSL dependencies.
You can disable libcurl at build time by supplying --disable-agent-libcurl to configure, in which case the server will fall back to using wget as its agent.
The configure script will attempt to auto-detect your Intel SGX SDK directory, but if for some reason it can't find it, then you should supply the path via --with-sgxsdk=PATH.
You can build the client for simulation mode using --enable-sgx-simulation. Note that Remote Attestation will fail for clients running in simulation mode, as this mode has no hardware protection.
Ensure you have the following:
Install OpenSSL 1.1.0 for Windows. The Win64 OpenSSL v1.1.0 package from Shining Light Productions is recommended. Select the option to copy the DLL's to your Windows system directory.
Download applink.c from GitHub and install it to OpenSSL's include\openssl directory.
Open the Solution file remote-attestation-sample.sln in the vs/ subdirectory.
Set the configuration to "Debug" and the platform to "x64".
Configure the client build
Open the client project properties
Navigate to "C/C++ -> General" and edit "Additional Include Directories" to include your OpenSSL include path. This is pre-set to C:\OpenSSL-Win64\include which is the default location for the recommended OpenSSL package for Windows.
Navigate to "Linker -> General" and edit "Additional Library Directories" to C:\OpenSSL-Win64\lib
Configure the server build
Open the sp project properties
Navigate to "Linker -> Additional Library Directories" and edit "Additional Library Directories" to include your OpenSSL library path. This is pre-set to C:\OpenSSL-Win64\lib\VC\ which is the default install location.
Build the Solution. The binaries will be written to vs\x64\Debug
By default, the server listens on port 7777 and the client connects to localhost. The server will make use of system proxy settings when contacting IAS.
The client and server use a very simplistic network protocol with no error handling and no encryption. Messages are sent using base 16 encoding (printed hex strings) for easy reading and interpretation. The intent here is to demonstrate the RA procedures and the modified Sigma protocol, not model a real-world application. It's assumed that a real ISV would integrate RA flows into their existing service infrastructure (e.g. a REST API implemented over a TLS session).
The build process automatically generates a file named policy on Linux (policy.cmd on
Windows) which contains the enclave verification policy settings. The server validates the enclave
by examining the contents of the report, and ensuring the following attributes in the report match
those specified in the policy file:
The enclave's MRSIGNER value (this is a SHA256 hash generated from the signing key)
The Product ID number ('''ProdID''' in Enclave.config.xml)
The software vendor's enclave version number ('''ISVSVN''' in Enclave.config.xml)
Whether or not the enclave was built in debug mode
The policy file is prepopulated with the correct values. By modifying the parameters in the policy file, you can create requirements that the enclave report doesn't meet and thus trigger attestation failures.
This demonstrates one of the key functions of remote attestation: the client enclave can be rejected if it originates from an unrecognized signer, contains an unrecognized product identifier, or if it's simply too old. The first prevents unauthorized and unknown enclaves from using the service. The latter two allows software venders to force end users to update their software.
The policy file is also set to specifically allow debug-mode enclaves. ''This is acceptable for a code sample, but a debug-mode enclave should never, ever be accepted by production service provider!''
Two wrapper scripts, run-client and run-server are provided for convenience. These are Bourne shell scripts that do the following:
settings and policy files (which are sourced as shell scripts)You can pass command-line options to the underlying executables via the wrapper scripts.
To execute:
Edit the settings file
Run the server:
./run-server [ options ] [ port ]Run the client:
./run-client [ options ] [ host[:port] ]The policy file is automatically generated for you from the Enclave metadata
in Enclave_config.xml and the signed enclave, Enclave.signed.so. In order to test
the policy validation functions, you can edit the parameters in this file and
restart the server. Your changes will be lost, however, if you do a
make clean.
Two wrapper scripts, run-client.cmd and run-server.cmd are provided for convenience. These are Windows CMD-style batch files that do the following:
Parse the settings.cmd and policy.cmd files (which are called as batch files)
Execute the client.exe or sp.exe applications with the corresponding command-line options.
You can pass command-line options to the underlying executables via the wrapper scripts. Note that it expects UNIX-style syntax (dashes), not Windows-style (slashes).
To execute:
Edit the settings.cmd file
Run the server:
run-server [ options ] [ port ]Run the client:
run-client [ options ] [ host[:port] ]The policy.cmd file is automatically generated for you from the Enclave metadata
in Enclave_config.xml and the signed enclave,Enclave.signed.dll`. In order to test
the policy validation functions, you can edit the parameters in this file and
restart the server. Your changes will be lost, however, if you clean or rebuild
the project.
Use verbose mode (-v) to see additional details about the messages sent between the client and server. This information is printed to stderr.
Use debug mode (-d) to view debugging information.
usage: client [ options ] [ host[:port] ]
Required:
-N, --nonce-file=FILE Set a nonce from a file containing a 32-byte
ASCII hex string
-P, --pubkey-file=FILE File containing the public key of the service
provider.
-S, --spid-file=FILE Set the SPID from a file containing a 32-byte
ASCII hex string
-d, --debug Show debugging information
-e, --epid-gid Get the EPID Group ID instead of performing
an attestation.
-l, --linkable Specify a linkable quote (default: unlinkable)
-m, --pse-manifest Include the PSE manifest in the quote
-n, --nonce=HEXSTRING Set a nonce from a 32-byte ASCII hex string
-p, --pubkey=HEXSTRING Specify the public key of the service provider
as an ASCII hex string instead of using the
default.
-q Generate a quote instead of performing an
attestation.
-r Generate a nonce using RDRAND
-s, --spid=HEXSTRING Set the SPID from a 32-byte ASCII hex string
-v, --verbose Print decoded RA messages to stderr
-z Read from stdin and write to stdout instead
connecting to a server.
By default, the client connects to a server running on localhost, port 7777, and attempts a remote attestation.
If -z is supplied, it will run interactively, accepting input from stdin and writing to stdout. This makes it possible to copy and paste output from the client to the server, and visa-versa.
The -q option will generate and print a quote instead of performing remote attestation. This quote can be submitted as-is to the Intel Attestation Service, and is intended for debugging RA workflows and IAS communications.
The -p and -P options let you override the service provider's public key for debugging and testing purposes. This key is normally hardcoded into the enclave to ensure it only attests to the expected service provider.
usage: sp [ options ] [ port ]
Required:
-A, --ias-signing-cafile=FILE
Specify the IAS Report Signing CA file.
-N, --mrsigner=HEXSTRING
Specify the MRSIGNER value of enclaves that
are allowed to attest. Enclaves signed by
other signing keys are rejected.
-R, --isv-product-id=INT
Specify the ISV Product Id for the service.
Only Enclaves built with this Product Id
will be accepted.
-V, --min-isv-svn=INT
The minimum ISV SVN that the service provider
will accept. Enclaves with a lower ISV SVN
are rejected.
Required (one of):
-S, --spid-file=FILE Set the SPID from a file containg a 32-byte
ASCII hex string.
-s, --spid=HEXSTRING Set the SPID from a 32-byte ASCII hex string.
Required (one of):
-I, --ias-pri-api-key-file=FILE
Set the IAS Primary Subscription Key from a
file containing a 32-byte ASCII hex string.
-i, --ias-pri-api-key=HEXSTRING
Set the IAS Primary Subscription Key from a
32-byte ASCII hex string.
Required (one of):
-J, --ias-sec-api-key-file=FILE
Set the IAS Secondary Subscription Key from a
file containing a 32-byte ASCII hex string.
-j, --ias-sec-api-key=HEXSTRING
Set the IAS Secondary Subscription Key from a
32-byte ASCII hex string.
Optional:
-B, --ca-bundle-file=FILE
Use the CA certificate bundle at FILE (default:
/etc/ssl/certs/ca-certificates.crt)
-D, --no-debug-enclave Reject Debug-mode enclaves (default: accept)
-G, --list-agents List available user agent names for --user-agent
-K, --service-key-file=FILE
The private key file for the service in PEM
format (default: use hardcoded key). The
client must be given the corresponding public
key. Can't combine with --key.
-P, --production Query the production IAS server instead of dev.
-X, --strict-trust-mode Don't trust enclaves that receive a
CONFIGURATION_NEEDED response from IAS
(default: trust)
-d, --debug Print debug information to stderr.
-g, --user-agent=NAME Use NAME as the user agent for contacting IAS.
-k, --key=HEXSTRING The private key as a hex string. See --key-file
for notes. Can't combine with --key-file.
-l, --linkable Request a linkable quote (default: unlinkable).
-p, --proxy=PROXYURL Use the proxy server at PROXYURL when contacting
IAS. Can't combine with --no-proxy
-r, --api-version=N Use version N of the IAS API (default: 4)
-v, --verbose Be verbose. Print message structure details and
the results of intermediate operations to stderr.
-x, --no-proxy Do not use a proxy (force a direct connection),
overriding environment.
-z --stdio Read from stdin and write to stdout instead of
running as a network server.You set the user agent with -g (a list of supported agents can be obtained from -G). On Linux, this is one of either wget or libcurl (unless the latter is disabled in the build configuration). On Windows, winhttp is the only agent.
By default, the server uses protocol version 4 when communicating with IAS. This can be changed with -r. Versions 1 and 2 have been deprecated.
You can override the service provider private key with -k or -K. As with the client, this key would normally be hardcoded into the server to prevent it from handling unauthorized clients.
You can force the server to use a proxy when communicating with IAS via -p, or to use a direct connection via -x.
As with the client, the server can be run in interactive mode via -z, accepting input from stdin and writing to stdout. This makes it possible to copy and paste output from the client to the server, and visa-versa.
By default, the server trusts enclaves that result in a CONFIGURATION_NEEDED response from IAS. Enable strict mode with -X to mark these enclaves as untrusted. This is a policy decision: the service provider should decide whether or not to trust the enclave in this circumstance.
---- Copy/Paste Msg0||Msg1 Below to SP -------------------------------------
000000006beaf1641d386157559ecbc95330c407442f5169c0adc13e9faa6b94e1011acbdfb157867dbd65633b023cc95a1d19eda341f5bbfed20eebdc04c708b99e40b2e00a0000
----------------------------------------------------------------------------
Waiting for msg2
---- Copy/Paste Msg3 Below to SP -------------------------------------------
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
----------------------------------------------------------------------------
---- Enclave Trust Status from Service Provider ----------------------------
Enclave TRUSTEDListening for connections on port 7777
Waiting for a client to connect...
Connection from 127.0.0.1
Waiting for msg0||msg1
---- Copy/Paste Msg2 Below to Client ---------------------------------------
e1c252d589daf123e18a20047d48d00dcc36312bba903b56ff62e3282a7991e4c355bc2c62427e003c7830b9f648cae480105fd065866b41fd0255038a9f54d6928a6b0e3cddad56eb3badaa3b63f71f00000100b5d1f9b84fe9e25690b220ad89465ba4d569b3eccbc26d0842666b466e745f8b5079ec3591be5c6ff6fe185d97244c06ffda6f1cb23f600e4b6a04b141df8e2f3c43bbcd7fc375b372c6044ccd414e3300000000
----------------------------------------------------------------------------
Waiting for msg3
---- Copy/Paste Msg4 Below to Client ---------------------------------------
010000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
----------------------------------------------------------------------------