zb: replace fastrand with rand

As we need cryptographically secure randomness for cookie sha1 method
next.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

zbus/Cargo.toml

@@ -26,7 +26,6 @@ enumflags2 = { version = "0.6.4", features = ["serde"] }
 serde-xml-rs = { version = "0.4.0", optional = true }
 derivative = "2.1"
 scoped-tls = "1.0.0"
-fastrand = "1.2.4"
 once_cell = "1.4.0"
 async-io = "1.3.1"
 futures-core = "0.3.8"
@@ -35,6 +34,7 @@ pollster = "0.2.0"
 futures-util = { version = "0.3.8", default-features = false, features = ["sink", "std"] }
 async-lock = "2.3.0"
 hex = "0.4.2"
+rand = "0.8.2"
 
 [dev-dependencies]
 zbus_polkit = { path = "../zbus_polkit", version = "1" }

zbus/src/guid.rs

@@ -22,10 +22,10 @@ impl Guid {
     ///
     /// [`Connection::new_unix_server`]: struct.Connection.html#method.new_unix_server
     pub fn generate() -> Self {
-        let r: Vec<u32> = repeat_with(|| fastrand::u32(..)).take(3).collect();
+        let r: Vec<u32> = repeat_with(rand::random::<u32>).take(3).collect();
         let r3 = match SystemTime::now().duration_since(UNIX_EPOCH) {
             Ok(n) => n.as_secs() as u32,
-            Err(_) => fastrand::u32(..),
+            Err(_) => rand::random::<u32>(),
         };
 
         let s = format!("{:08x}{:08x}{:08x}{:08x}", r[0], r[1], r[2], r3);