diff --git a/pkgs/development/libraries/openldap/default.nix b/pkgs/development/libraries/openldap/default.nix
index 39831a3baf08..fe4704341ef5 100644
--- a/pkgs/development/libraries/openldap/default.nix
+++ b/pkgs/development/libraries/openldap/default.nix
@@ -1,4 +1,4 @@
-{ lib, stdenv, fetchurl, openssl, db, groff, libtool
+{ lib, stdenv, fetchurl, openssl, db, groff, libtool, libsodium
 , withCyrusSasl ? true
 , cyrus_sasl
 }:
@@ -19,7 +19,7 @@ stdenv.mkDerivation rec {
 
   nativeBuildInputs = [ groff ];
 
-  buildInputs = [ openssl cyrus_sasl db libtool ];
+  buildInputs = [ openssl cyrus_sasl db libsodium libtool ];
 
   # Disable install stripping as it breaks cross-compiling.
   # We strip binaries anyway in fixupPhase.
@@ -46,6 +46,7 @@ stdenv.mkDerivation rec {
   postBuild = ''
     make $makeFlags CC=$CC -C contrib/slapd-modules/passwd/sha2
     make $makeFlags CC=$CC -C contrib/slapd-modules/passwd/pbkdf2
+    make $makeFlags CC=$CC -C contrib/slapd-modules/passwd/argon2
   '';
 
   doCheck = false; # needs a running LDAP server
@@ -54,6 +55,9 @@ stdenv.mkDerivation rec {
     "sysconfdir=$(out)/etc"
     "localstatedir=$(out)/var"
     "moduledir=$(out)/lib/modules"
+    # The argon2 module hardcodes /usr/bin/install as the path for the
+    # `install` binary, which is overridden here.
+    "INSTALL=install"
   ];
 
   # 1. Libraries left in the build location confuse `patchelf --shrink-rpath`
@@ -76,6 +80,7 @@ stdenv.mkDerivation rec {
   postInstall = ''
     make $installFlags install -C contrib/slapd-modules/passwd/sha2
     make $installFlags install -C contrib/slapd-modules/passwd/pbkdf2
+    make $installFlags install-lib -C contrib/slapd-modules/passwd/argon2
     chmod +x "$out"/lib/*.{so,dylib}
   '';