diff --git a/source/Makefile.in b/source/Makefile.in
index 32e8dee1230..3a5f31a1b57 100644
--- a/source/Makefile.in
+++ b/source/Makefile.in
@@ -368,6 +368,7 @@ AUTH_RHOSTS_OBJ = auth/auth_rhosts.o
 AUTH_SERVER_OBJ = auth/auth_server.o
 AUTH_UNIX_OBJ = auth/auth_unix.o
 AUTH_WINBIND_OBJ = auth/auth_winbind.o
+AUTH_SCRIPT_OBJ = auth/auth_script.o
 
 AUTH_OBJ = auth/auth.o @AUTH_STATIC@ auth/auth_util.o auth/auth_compat.o \
 	   auth/auth_ntlmssp.o \
@@ -1165,6 +1166,10 @@ bin/domain.@SHLIBEXT@: $(AUTH_DOMAIN_OBJ:.o=.@PICSUFFIX@)
 	@echo "Building plugin $@"
 	@$(SHLD) $(LDSHFLAGS) -o $@ $(AUTH_DOMAIN_OBJ:.o=.@PICSUFFIX@) @SONAMEFLAG@`basename $@`
 
+bin/script.@SHLIBEXT@: $(AUTH_SCRIPT_OBJ:.o=.@PICSUFFIX@)
+	@echo "Building plugin $@"
+	@$(SHLD) $(LDSHFLAGS) -o $@ $(AUTH_SCRIPT_OBJ:.o=.@PICSUFFIX@) @SONAMEFLAG@`basename $@`
+
 bin/smbserver.@SHLIBEXT@: $(AUTH_SERVER_OBJ:.o=.@PICSUFFIX@)
 	@echo "Building plugin $@"
 	@$(SHLD) $(LDSHFLAGS) -o $@ $(AUTH_SERVER_OBJ:.o=.@PICSUFFIX@) @SONAMEFLAG@`basename $@`
diff --git a/source/auth/auth_script.c b/source/auth/auth_script.c
new file mode 100644
index 00000000000..1a715fca319
--- /dev/null
+++ b/source/auth/auth_script.c
@@ -0,0 +1,155 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   Call out to a shell script for an authentication check.
+
+   Copyright (C) Jeremy Allison 2005.
+   
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include "includes.h"
+
+#undef malloc
+
+#undef DBGC_CLASS
+#define DBGC_CLASS DBGC_AUTH
+
+/* Create a string containing the supplied :
+ * domain\n
+ * user\n
+ * ascii hex challenge\n
+ * ascii hex LM response\n
+ * ascii hex NT response\n\0
+ * and execute a shell script to check this.
+ * Allows external programs to create users on demand.
+ * Script returns zero on success, non-zero on fail.
+ */
+
+static NTSTATUS script_check_user_credentials(const struct auth_context *auth_context,
+					void *my_private_data, 
+					TALLOC_CTX *mem_ctx,
+					const auth_usersupplied_info *user_info, 
+					auth_serversupplied_info **server_info)
+{
+	const char *script = lp_parm_const_string( GLOBAL_SECTION_SNUM, "auth_script", "script", NULL);
+	char *secret_str;
+	size_t secret_str_len;
+	char hex_str[49];
+	int ret, i;
+
+	if (!script) {
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+
+	if (!user_info) {
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+
+	if (!auth_context) {
+		DEBUG(3,("script_check_user_credentials: no auth_info !\n"));
+		return NT_STATUS_INVALID_PARAMETER;
+	}		
+
+	secret_str_len = strlen(user_info->domain.str) + 1 +
+			strlen(user_info->smb_name.str) + 1 +
+			16 + 1 + /* 8 bytes of challenge going to 16 */
+			48 + 1 + /* 24 bytes of challenge going to 48 */
+			48 + 1;
+
+	secret_str = malloc(secret_str_len);
+	if (!secret_str) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	safe_strcpy( secret_str, user_info->domain.str, secret_str_len - 1);
+	safe_strcat( secret_str, "\n", secret_str_len - 1);
+	safe_strcat( secret_str, user_info->smb_name.str, secret_str_len - 1);
+	safe_strcat( secret_str, "\n", secret_str_len - 1);
+
+	for (i = 0; i < 8; i++) {
+		slprintf(&hex_str[i*2], 3, "%02X", auth_context->challenge.data[i]);
+	}
+	safe_strcat( secret_str, hex_str, secret_str_len - 1);
+	safe_strcat( secret_str, "\n", secret_str_len - 1);
+
+	if (user_info->lm_resp.data) {
+		for (i = 0; i < 24; i++) {
+			slprintf(&hex_str[i*2], 3, "%02X", user_info->lm_resp.data[i]);
+		}
+		safe_strcat( secret_str, hex_str, secret_str_len - 1);
+	}
+	safe_strcat( secret_str, "\n", secret_str_len - 1);
+
+	if (user_info->nt_resp.data) {
+		for (i = 0; i < 24; i++) {
+			slprintf(&hex_str[i*2], 3, "%02X", user_info->nt_resp.data[i]);
+		}
+		safe_strcat( secret_str, hex_str, secret_str_len - 1);
+	}
+	safe_strcat( secret_str, "\n", secret_str_len - 1);
+
+	DEBUG(10,("script_check_user_credentials: running %s with parameters:\n%s\n",
+		script, secret_str ));
+
+	ret = smbrunsecret( script, secret_str);
+
+	SAFE_FREE(secret_str);
+
+	if (ret) {
+		DEBUG(1,("script_check_user_credentials: failed to authenticate %s\\%s\n",
+			user_info->domain.str, user_info->smb_name.str ));
+		/* auth failed. */
+		return NT_STATUS_NO_SUCH_USER;
+	}
+
+	/* Cause the auth system to keep going.... */
+	return NT_STATUS_NOT_IMPLEMENTED;
+}
+
+/* module initialisation */
+static NTSTATUS auth_init_script(struct auth_context *auth_context, const char *param, auth_methods **auth_method) 
+{
+	if (!make_auth_methods(auth_context, auth_method)) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	(*auth_method)->name = "script";
+	(*auth_method)->auth = script_check_user_credentials;
+
+	if (param && *param) {
+		/* we load the 'fallback' module - if script isn't here, call this
+		   module */
+		if (!load_auth_module(auth_context, param, (auth_methods **)&(*auth_method)->private_data)) {
+			return NT_STATUS_UNSUCCESSFUL;
+		}
+		
+	}
+	return NT_STATUS_OK;
+}
+
+#if 0
+/* Define this to build static. */
+NTSTATUS auth_script_init(void)
+{
+	return smb_register_auth(AUTH_INTERFACE_VERSION, "script", auth_init_script);
+}
+#else
+/* Define this to build shared. */
+NTSTATUS init_module(void)
+{
+	return smb_register_auth(AUTH_INTERFACE_VERSION, "script", auth_init_script);
+}
+#endif
diff --git a/source/configure.in b/source/configure.in
index c0afe0de1d6..dbb27d1a60f 100644
--- a/source/configure.in
+++ b/source/configure.in
@@ -460,7 +460,7 @@ dnl These have to be built static:
 default_static_modules="pdb_smbpasswd pdb_tdbsam rpc_lsa rpc_samr rpc_reg rpc_lsa_ds rpc_wks rpc_svcctl rpc_net rpc_dfs rpc_srv rpc_spoolss rpc_eventlog auth_rhosts auth_sam auth_unix auth_winbind auth_server auth_domain auth_builtin printerdb_file"
 
 dnl These are preferably build shared, and static if dlopen() is not available
-default_shared_modules="vfs_recycle vfs_audit vfs_extd_audit vfs_full_audit vfs_netatalk vfs_fake_perms vfs_default_quota vfs_readonly vfs_cap vfs_expand_msdfs vfs_shadow_copy charset_CP850 charset_CP437"
+default_shared_modules="vfs_recycle vfs_audit vfs_extd_audit vfs_full_audit vfs_netatalk vfs_fake_perms vfs_default_quota vfs_readonly vfs_cap vfs_expand_msdfs vfs_shadow_copy charset_CP850 charset_CP437 auth_script"
 
 if test "x$developer" = xyes; then
    default_static_modules="$default_static_modules rpc_echo"
@@ -4973,6 +4973,7 @@ SMB_MODULE(auth_winbind, \$(AUTH_WINBIND_OBJ), "bin/winbind.$SHLIBEXT", AUTH)
 SMB_MODULE(auth_server, \$(AUTH_SERVER_OBJ), "bin/smbserver.$SHLIBEXT", AUTH)
 SMB_MODULE(auth_domain, \$(AUTH_DOMAIN_OBJ), "bin/domain.$SHLIBEXT", AUTH)
 SMB_MODULE(auth_builtin, \$(AUTH_BUILTIN_OBJ), "bin/builtin.$SHLIBEXT", AUTH)
+SMB_MODULE(auth_script, \$(AUTH_SCRIPT_OBJ), "bin/script.$SHLIBEXT", AUTH)
 SMB_SUBSYSTEM(AUTH,auth/auth.o)
 
 SMB_MODULE(vfs_recycle, \$(VFS_RECYCLE_OBJ), "bin/recycle.$SHLIBEXT", VFS)
diff --git a/source/lib/smbrun.c b/source/lib/smbrun.c
index 43cb209174e..13e330dd97a 100644
--- a/source/lib/smbrun.c
+++ b/source/lib/smbrun.c
@@ -55,7 +55,7 @@ run a command being careful about uid/gid handling and putting the output in
 outfd (or discard it if outfd is NULL).
 ****************************************************************************/
 
-int smbrun(char *cmd, int *outfd)
+int smbrun(const char *cmd, int *outfd)
 {
 	pid_t pid;
 	uid_t uid = current_user.uid;
@@ -186,7 +186,7 @@ outfd (or discard it if outfd is NULL).
 sends the provided secret to the child stdin.
 ****************************************************************************/
 
-int smbrunsecret(char *cmd, char *secret)
+int smbrunsecret(const char *cmd, const char *secret)
 {
 	pid_t pid;
 	uid_t uid = current_user.uid;