graphene/Documentation/oldwiki/Graphene-SGX-Manifest-Syntax.md

Graphene SGX Manifest Syntax

The basic manifest syntax for Graphene is described in Graphene Manifest Syntax. If Graphene is not running with SGX, the SGX-specific syntax is ignored. All keys in the SGX-specific syntax are optional. If the keys are not specified, Graphene will use the default values.

Basic SGX-specific Syntax

Enclave Size

sgx.enclave_size=[SIZE]
(default: 256M)

This syntax specifies the size of the enclave set during enclave creation time (recall that SGX v1 requires a predetermined maximum size of the enclave). The PAL and library OS code/data count towards this size value, as well as the application memory itself: application's code, stack, heap, loaded application libraries, etc. The application cannot allocate memory that exceeds this limit.

Number of Threads

sgx.thread_num=[NUM]
(Default: 4)

This syntax specifies the maximum number of threads that can be created inside the enclave (recall that SGX v1 requires a predetermined maximum number of thread slots). The application cannot have more threads than this limit at a time (however, it is possible to create new threads after old threads are destroyed).

Debug/Production Enclave

sgx.debug=[1|0]
(Default: 1)

This syntax specifies whether the enclave can be debugged. Set it to 1 for a debug enclave and to 0 for a production enclave.

Optional CPU features (AVX, AVX512, MPX)

sgx.require_avx=[1|0]
sgx.require_avx512=[1|0]
sgx.require_mpx=[1|0]
(Default: 0)

This syntax ensures that the CPU features are available and enabled for the enclave. If the options are set in the manifest but the features are unavailable on the platform, enclave initialization should fail. If the options are unset, enclave initialization should succeed even if these features are unavailable on the platform.

ISV Product ID and SVN

sgx.isvprodid=[NUM]
sgx.isnsvn=[NUM]
(Default: 0)

This syntax specifies the ISV Product ID and SVN to be added to the enclave signature.

Trusted Files and Child Processes

Trusted Files

sgx.trusted_files.[identifier]=[URI]

This syntax specifies the files to be cryptographically hashed, and thus allowed to be loaded into the enclave. The signer tool will automatically generate hashes of these files and add them into the SGX-specific manifest (.manifest.sgx). This is especially useful for shared libraries: a trusted library cannot be silently replaced by a malicious host because the hash verification will fail.

Allowed Files

sgx.allowed_files.[identifier]=[URI]

This syntax specifies the files that are allowed to be loaded into the enclave unconditionally. These files are not cryptographically hashed and are thus not protected. It is insecure to allow files containing code or critical information; developers must not allow files blindly!

Allowing File Creation

sgx.allow_file_creation=[1|0]
(Default: 0)

This syntax specifies whether file creation is allowed from within the enclave. Set it to 1 to allow enclaves to create files and to 0 otherwise. Files created during enclave execution do not need to be marked as allowed_files or trusted_files.

Trusted Child Processes

sgx.trusted_children.[identifier]=[URI of signature (.sig)]

This syntax specifies the signatures of allowed child processes of the current application. Upon process creation, the enclave in the current (parent) process will attest the enclave in the child process, by comparing to the signatures of the trusted children. If the child process is not trusted, the enclave will refuse to communicate with it.

File Check Policy

sgx.file_check_policy=[strict|allow_all_but_log]
(Default: strict)

This syntax specifies the file check policy, determining the behavior of authentication when opening files. By default, only files explicitly listed as _trustedfiles or _allowedfiles declared in the manifest are allowed for access. If the file check policy is allow_all_but_log, all files other than trusted and allowed are allowed for access, and Graphene-SGX emits a warning message for every such file. This is a convenient way to determine the set of files that the ported application uses.