From aa99d954faae0446664f82b0c3c597664845ca90 Mon Sep 17 00:00:00 2001
From: Chris Denton <chris@chrisdenton.dev>
Date: Wed, 21 Feb 2024 08:40:02 -0300
Subject: [PATCH] Test windows random shims

---
 .../miri/tests/pass/shims/windows-rand.rs     | 41 +++++++++++++++++++
 1 file changed, 41 insertions(+)
 create mode 100644 src/tools/miri/tests/pass/shims/windows-rand.rs

diff --git a/src/tools/miri/tests/pass/shims/windows-rand.rs b/src/tools/miri/tests/pass/shims/windows-rand.rs
new file mode 100644
index 0000000000000..e2bcb7bd7cb77
--- /dev/null
+++ b/src/tools/miri/tests/pass/shims/windows-rand.rs
@@ -0,0 +1,41 @@
+//@only-target-windows: this directly tests windows only random functions
+use core::ffi::c_void;
+use core::mem::size_of_val;
+use core::ptr::null_mut;
+
+// Windows API definitions.
+type NTSTATUS = i32;
+type BOOLEAN = u8;
+const BCRYPT_USE_SYSTEM_PREFERRED_RNG: u32 = 0x00000002;
+const BCRYPT_RNG_ALG_HANDLE: *mut c_void = 0x81 as *mut c_void;
+#[link(name = "bcrypt")]
+extern "system" {
+    fn BCryptGenRandom(
+        halgorithm: *mut c_void,
+        pbbuffer: *mut u8,
+        cbbuffer: u32,
+        dwflags: u32,
+    ) -> NTSTATUS;
+}
+#[link(name = "advapi32")]
+extern "system" {
+    #[link_name = "SystemFunction036"]
+    fn RtlGenRandom(RandomBuffer: *mut u8, RandomBufferLength: u32) -> BOOLEAN;
+}
+
+fn main() {
+    let mut key = [0u8; 24];
+    let len: u32 = size_of_val(&key).try_into().unwrap();
+    let ret = unsafe {
+        BCryptGenRandom(null_mut(), key.as_mut_ptr(), len, BCRYPT_USE_SYSTEM_PREFERRED_RNG)
+    };
+    // NTSTATUS codes use the high bit to indicate an error
+    assert!(ret >= 0);
+
+    let ret = unsafe { BCryptGenRandom(BCRYPT_RNG_ALG_HANDLE, key.as_mut_ptr(), len, 0) };
+    assert!(ret >= 0);
+
+    let ret = unsafe { RtlGenRandom(key.as_mut_ptr(), len) };
+    // RtlGenRandom returns a BOOLEAN where 0 indicates an error
+    assert_ne!(ret, 0);
+}