support sgx-target

Author: akash-fortanix

Cargo.toml

@@ -65,6 +65,9 @@ fuchsia-zircon = { version = "0.3.2", optional = true }
 stdweb = { version = "0.4", optional = true }
 wasm-bindgen = { version = "0.2.12", optional = true }
 
+[target.'cfg(target_env = "sgx")'.dependencies]
+rdrand = "0.4.0"
+
 [dev-dependencies]
 # This has a histogram implementation used for testing uniformity.
 average = "0.9.2"
@@ -74,3 +77,7 @@ autocfg = "0.1"
 
 [package.metadata.docs.rs]
 all-features = true
+
+[patch.crates-io]
+rand_core = { path = "rand_core", version = "0.3", default-features = false }
+

src/lib.rs

@@ -72,6 +72,9 @@ extern crate stdweb;
 #[cfg(all(target_arch = "wasm32", feature = "wasm-bindgen"))]
 extern crate wasm_bindgen;
 
+#[cfg(target_env = "sgx")]
+extern crate rdrand;
+
 extern crate rand_core;
 extern crate rand_isaac;    // only for deprecations
 extern crate rand_chacha;    // only for deprecations

src/rngs/mod.rs

@@ -194,6 +194,7 @@ pub use self::std::StdRng;
               windows,
               all(target_arch = "wasm32", feature = "stdweb"),
               all(target_arch = "wasm32", feature = "wasm-bindgen"),
+              target_env = "sgx",
 )))]
 mod os;
 

src/rngs/os.rs

@@ -1191,6 +1191,40 @@ mod imp {
     }
 }
 
+#[cfg(target_env = "sgx")]
+mod imp {
+    use super::OsRngImpl;
+    use Error;
+    use rdrand::RdRand;
+    use rand_core::RngCore;
+    use std::fmt::{Debug, Formatter, Result as FmtResult};
+
+    #[derive(Clone)]
+    pub struct OsRng{
+        gen: RdRand
+    }
+
+    impl OsRngImpl for OsRng {
+        fn new() -> Result<OsRng, Error> {
+            let rng = RdRand::new()?;
+            Ok(OsRng{ gen: rng })
+        }
+
+        fn fill_chunk(&mut self, dest: &mut [u8]) -> Result<(), Error> {
+            self.gen.try_fill_bytes(dest)
+        }
+
+        fn method_str(&self) -> &'static str { "RDRAND" }
+    }
+
+    impl Debug for OsRng {
+        fn fmt(&self, f: &mut Formatter) -> FmtResult {
+            f.debug_struct("OsRng")
+                .field("gen", &String::from("No information"))
+                .finish()
+        }
+    }
+}
 
 #[cfg(test)]
 mod test {