This may actually use the right openssl source.

nixos/openssl-111k.nix

-self: super: rec {
-  openssl_1_1 = super.openssl_1_1.overrideAttrs (old: {
+self: super: {
+  openssl_1_1 = super.openssl_1_1.overrideAttrs (old: rec {
     version = "1.1.1k";
-    sha256 = "1whinyw402z3b9xlb3qaxv4b9sk4w1bgh9k0y8df1z4x3yy92fhz";
-    withDocs = false;
+    pname = "openssl";
+    name = "${pname}-${version}";
+    src = builtins.fetchurl {
+      url = "https://www.openssl.org/source/${pname}-${version}.tar.gz";
+      sha256 = "1rdfzcrxy9y38wqdw5942vmdax9hjhgrprzxm42csal7p5shhal9";
+    };
   });
-
-  openssl = openssl_1_1;
 }