chore: nix flake update

pkgs/busybox/default.nix

@@ -1,6 +1,7 @@
 {
   stdenv,
   lib,
+  pkgs,
   buildPackages,
   fetchurl,
   fetchpatch,
@@ -57,15 +58,12 @@ in
 
 stdenv.mkDerivation rec {
   pname = "busybox";
-  version = "1.36.1";
+  version = pkgs.busybox.version;
 
   # Note to whoever is updating busybox: please verify that:
   # nix-build pkgs/stdenv/linux/make-bootstrap-tools.nix -A test
   # still builds after the update.
-  src = fetchurl {
-    url = "https://busybox.net/downloads/${pname}-${version}.tar.bz2";
-    sha256 = "sha256-uMwkyVdNgJ5yecO+NJeVxdXOtv3xnKcJ+AzeUOR94xQ=";
-  };
+  src = pkgs.busybox.src;
 
   hardeningDisable = [
     "format"

pkgs/openssl/default.nix

@@ -1,5 +1,6 @@
 {
   lib,
+  pkgs,
   stdenv,
   fetchurl,
   perl,
@@ -18,13 +19,9 @@
 
 stdenv.mkDerivation rec {
     pname = "openssl";
-    version = "3.4.1";
-    hash = "sha256-ACotazC1i/S+pGxDvdljZar42qbEKHgqpP7uBtoZffM=";
+    version = pkgs.openssl.version;
 
-    src = fetchurl {
-      url = "https://github.com/openssl/openssl/releases/download/openssl-${version}/openssl-${version}.tar.gz";
-      hash = hash;
-    };
+    src = pkgs.openssl.src;
 
     outputs = [ "out" ];