Move check for global Crypto object to getRandomValues

Author: daxpedda

src/backends/wasm_js.rs

@@ -13,25 +13,18 @@ use wasm_bindgen::{prelude::wasm_bindgen, JsValue};
 // See https://developer.mozilla.org/en-US/docs/Web/API/Crypto/getRandomValues
 const MAX_BUFFER_SIZE: usize = 65536;
 
-pub fn fill_inner(dest: &mut [MaybeUninit<u8>]) -> Result<(), Error> {
-    CRYPTO.with(|crypto| {
-        let crypto = crypto.as_ref().ok_or(Error::WEB_CRYPTO)?;
-        inner(crypto, dest)
-    })
-}
-
 #[cfg(not(target_feature = "atomics"))]
-fn inner(crypto: &Crypto, dest: &mut [MaybeUninit<u8>]) -> Result<(), Error> {
+pub fn fill_inner(dest: &mut [MaybeUninit<u8>]) -> Result<(), Error> {
     for chunk in dest.chunks_mut(MAX_BUFFER_SIZE) {
-        if crypto.get_random_values(chunk).is_err() {
-            return Err(Error::WEB_GET_RANDOM_VALUES);
+        if get_random_values(chunk).is_err() {
+            return Err(Error::WEB_CRYPTO);
         }
     }
     Ok(())
 }
 
 #[cfg(target_feature = "atomics")]
-fn inner(crypto: &Crypto, dest: &mut [MaybeUninit<u8>]) -> Result<(), Error> {
+pub fn fill_inner(dest: &mut [MaybeUninit<u8>]) -> Result<(), Error> {
     // getRandomValues does not work with all types of WASM memory,
     // so we initially write to browser memory to avoid exceptions.
     let buf_len = usize::min(dest.len(), MAX_BUFFER_SIZE);
@@ -52,8 +45,8 @@ fn inner(crypto: &Crypto, dest: &mut [MaybeUninit<u8>]) -> Result<(), Error> {
             &buf.subarray(0, chunk_len)
         };
 
-        if crypto.get_random_values(sub_buf).is_err() {
-            return Err(Error::WEB_GET_RANDOM_VALUES);
+        if get_random_values(sub_buf).is_err() {
+            return Err(Error::WEB_CRYPTO);
         }
 
         // SAFETY: `sub_buf`'s length is the same length as `chunk`
@@ -64,16 +57,11 @@ fn inner(crypto: &Crypto, dest: &mut [MaybeUninit<u8>]) -> Result<(), Error> {
 
 #[wasm_bindgen]
 extern "C" {
-    // Web Crypto API: Crypto interface (https://www.w3.org/TR/WebCryptoAPI/)
-    type Crypto;
-    // Holds the global `Crypto` object.
-    #[wasm_bindgen(thread_local_v2, js_namespace = globalThis, js_name = crypto)]
-    static CRYPTO: Option<Crypto>;
     // Crypto.getRandomValues()
     #[cfg(not(target_feature = "atomics"))]
-    #[wasm_bindgen(method, js_name = getRandomValues, catch)]
-    fn get_random_values(this: &Crypto, buf: &mut [MaybeUninit<u8>]) -> Result<(), JsValue>;
+    #[wasm_bindgen(js_namespace = ["globalThis", "crypto"], js_name = getRandomValues, catch)]
+    fn get_random_values(buf: &mut [MaybeUninit<u8>]) -> Result<(), JsValue>;
     #[cfg(target_feature = "atomics")]
-    #[wasm_bindgen(method, js_name = getRandomValues, catch)]
-    fn get_random_values(this: &Crypto, buf: &js_sys::Uint8Array) -> Result<(), JsValue>;
+    #[wasm_bindgen(js_namespace = ["globalThis", "crypto"], js_name = getRandomValues, catch)]
+    fn get_random_values(buf: &js_sys::Uint8Array) -> Result<(), JsValue>;
 }

src/error.rs

@@ -39,8 +39,6 @@ impl Error {
     pub const NO_RDRAND: Error = Self::new_internal(6);
     /// The environment does not support the Web Crypto API.
     pub const WEB_CRYPTO: Error = Self::new_internal(7);
-    /// Calling Web Crypto API `crypto.getRandomValues` failed.
-    pub const WEB_GET_RANDOM_VALUES: Error = Self::new_internal(8);
     /// On VxWorks, call to `randSecure` failed (random number generator is not yet initialized).
     pub const VXWORKS_RAND_SECURE: Error = Self::new_internal(11);
     /// Calling Windows ProcessPrng failed.
@@ -155,7 +153,6 @@ fn internal_desc(error: Error) -> Option<&'static str> {
         Error::FAILED_RDRAND => "RDRAND: failed multiple times: CPU issue likely",
         Error::NO_RDRAND => "RDRAND: instruction not supported",
         Error::WEB_CRYPTO => "Web Crypto API is unavailable",
-        Error::WEB_GET_RANDOM_VALUES => "Calling Web API crypto.getRandomValues failed",
         Error::VXWORKS_RAND_SECURE => "randSecure: VxWorks RNG module is not initialized",
         Error::WINDOWS_PROCESS_PRNG => "ProcessPrng: Windows system function failure",
         Error::RNDR_FAILURE => "RNDR: Could not generate a random number",