rust: Expose crypto_rand() as an impl of rand_core::RngCore.

1 files changed, 11 insertions, 19 deletions

diff --git a/src/rust/external/crypto_rand.rs b/src/rust/external/crypto_rand.rs
index 19b9ab2816..af1ade0161 100644
--- a/src/rust/external/crypto_rand.rs
+++ b/src/rust/external/crypto_rand.rs
@@ -11,23 +11,18 @@
 
 use std::time::Duration;
 
-use libc::c_char;
 use libc::c_double;
 use libc::c_int;
-use libc::c_uint;
-use libc::c_void;
 use libc::size_t;
 use libc::time_t;
 use libc::uint8_t;
-use libc::uint64_t;
 
 extern "C" {
     fn crypto_seed_rng() -> c_int;
+    fn crypto_rand(out: *mut uint8_t, out_len: size_t);
     fn crypto_strongest_rand(out: *mut uint8_t, out_len: size_t);
     fn crypto_rand_time_range(min: time_t, max: time_t) -> time_t;
     fn crypto_rand_double() -> c_double;
-    // fn crypto_random_hostname(min_rand_len: c_int, max_rand_len: c_int,
-    //                           prefix: *const c_char, suffix: *const c_char) -> *mut c_char;
 }
 
 /// Seed OpenSSL's random number generator with bytes from the operating
@@ -48,7 +43,16 @@ pub fn c_tor_crypto_seed_rng() -> bool {
     }
 }
 
-/// Fill the bytes of `dest` with strong random data.
+/// Fill the bytes of `dest` with random data.
+pub fn c_tor_crypto_rand(dest: &mut [u8]) {
+    unsafe {
+        crypto_rand(dest.as_mut_ptr(), dest.len() as size_t);
+    }
+}
+
+/// Fill the bytes of `dest` with "strong" random data by hashing
+/// together randomness obtained from OpenSSL's RNG and the operating
+/// system.
 pub fn c_tor_crypto_strongest_rand(dest: &mut [u8]) {
     // We'll let the C side panic if the len is larger than
     // MAX_STRONGEST_RAND_SIZE, rather than potentially panicking here.  A
@@ -81,15 +85,3 @@ pub fn c_tor_crypto_rand_double() -> f64 {
     }
 }
 
-#[cfg(test)]
-mod test {
-    use super::*;
-
-    #[test]
-    fn test_layout_tor_weak_rng_t() {
-        assert_eq!(::std::mem::size_of::<tor_weak_rng_t>(), 0usize,
-                   concat!("Size of: ", stringify!(tor_weak_rng_t)));
-        assert_eq!(::std::mem::align_of::<tor_weak_rng_t>(), 1usize,
-                   concat!("Alignment of ", stringify!(tor_weak_rng_t)));
-    }
-}