refactor(node/crypto): port polyfill to Rust for randomInt, randomFill, randomFillSync (#18658)

Pretty much as per the title, I'd welcome some feedback especially
around the
array/buffer handling in the two randomFill functions.

1 files changed, 12 insertions, 0 deletions

diff --git a/ext/node/crypto/mod.rs b/ext/node/crypto/mod.rs
index 55a7a5870..f818b96af 100644
--- a/ext/node/crypto/mod.rs
+++ b/ext/node/crypto/mod.rs
@@ -9,6 +9,8 @@ use deno_core::StringOrBuffer;
 use deno_core::ZeroCopyBuf;
 use hkdf::Hkdf;
 use num_bigint::BigInt;
+use rand::distributions::Distribution;
+use rand::distributions::Uniform;
 use rand::Rng;
 use std::future::Future;
 use std::rc::Rc;
@@ -478,3 +480,13 @@ pub async fn op_node_hkdf_async(
   })
   .await?
 }
+
+#[op]
+pub fn op_node_random_int(min: i32, max: i32) -> Result<i32, AnyError> {
+  let mut rng = rand::thread_rng();
+  // Uniform distribution is required to avoid Modulo Bias
+  // https://en.wikipedia.org/wiki/Fisher–Yates_shuffle#Modulo_bias
+  let dist = Uniform::from(min..max);
+
+  Ok(dist.sample(&mut rng))
+}