r11200: Reposition the creation of the kerberos keytab for GSSAPI and Krb5

authentication.  This pulls the creating of the keytab back to the
credentials code, and removes the special case of 'use keberos keytab
= yes' for now.

This allows (and requires) the callers to specify the credentials for
the server credentails to GENSEC.  This allows kpasswdd (soon to be
added) to use a different set of kerberos credentials.

The 'use kerberos keytab' code will be moved into the credentials
layer, as the layers below now expect a keytab.

We also now allow for the old secret to be stored into the
credentials, allowing service password changes.

Andrew Bartlett
(This used to be commit 205f77c579ac8680c85f713a76de5767189c627b)

1 files changed, 16 insertions, 191 deletions

diff --git a/source4/auth/kerberos/kerberos_verify.c b/source4/auth/kerberos/kerberos_verify.c
index 514acde5eb..13d2c9fc26 100644
--- a/source4/auth/kerberos/kerberos_verify.c
+++ b/source4/auth/kerberos/kerberos_verify.c
@@ -64,156 +64,6 @@ DATA_BLOB unwrap_pac(TALLOC_CTX *mem_ctx, DATA_BLOB *auth_data)
 }
 
 /**********************************************************************************
- Try to verify a ticket using the system keytab... the system keytab has kvno -1 entries, so
- it's more like what microsoft does... see comment in utils/net_ads.c in the
- ads_keytab_add_entry function for details.
-***********************************************************************************/
-
-static krb5_error_code ads_keytab_verify_ticket(TALLOC_CTX *mem_ctx, krb5_context context, 
-						krb5_auth_context *auth_context,
-						const char *service,
-						const krb5_data *p_packet, 
-						krb5_flags *ap_req_options,
-						krb5_ticket **pp_tkt,
-						krb5_keyblock **keyblock)
-{
-	krb5_error_code ret = 0;
-	krb5_keytab keytab = NULL;
-	krb5_kt_cursor kt_cursor;
-	krb5_keytab_entry kt_entry;
-	char *valid_princ_formats[7] = { NULL, NULL, NULL, NULL, NULL, NULL, NULL };
-	char *entry_princ_s = NULL;
-	const char *my_name, *my_fqdn;
-	int i;
-	int number_matched_principals = 0;
-	const char *last_error_message;
-
-	/* Generate the list of principal names which we expect
-	 * clients might want to use for authenticating to the file
-	 * service.  We allow name$,{host,service}/{name,fqdn,name.REALM}.
-	 * (where service is specified by the caller) */
-
-	my_name = lp_netbios_name();
-
-	my_fqdn = name_to_fqdn(mem_ctx, my_name);
-
-	asprintf(&valid_princ_formats[0], "%s$@%s", my_name, lp_realm());
-	asprintf(&valid_princ_formats[1], "host/%s@%s", my_name, lp_realm());
-	asprintf(&valid_princ_formats[2], "host/%s@%s", my_fqdn, lp_realm());
-	asprintf(&valid_princ_formats[3], "host/%s.%s@%s", my_name, lp_realm(), lp_realm());
-	asprintf(&valid_princ_formats[4], "%s/%s@%s", service, my_name, lp_realm());
-	asprintf(&valid_princ_formats[5], "%s/%s@%s", service, my_fqdn, lp_realm());
-	asprintf(&valid_princ_formats[6], "%s/%s.%s@%s", service, my_name, lp_realm(), lp_realm());
-
-	ZERO_STRUCT(kt_entry);
-	ZERO_STRUCT(kt_cursor);
-
-	ret = krb5_kt_default(context, &keytab);
-	if (ret) {
-		last_error_message = smb_get_krb5_error_message(context, ret, mem_ctx);
-		DEBUG(1, ("ads_keytab_verify_ticket: krb5_kt_default failed (%s)\n", 
-			  last_error_message));
-		goto out;
-	}
-
-	/* Iterate through the keytab.  For each key, if the principal
-	 * name case-insensitively matches one of the allowed formats,
-	 * try verifying the ticket using that principal. */
-
-	ret = krb5_kt_start_seq_get(context, keytab, &kt_cursor);
-	if (ret == KRB5_KT_END || ret == ENOENT ) {
-		last_error_message = smb_get_krb5_error_message(context, ret, mem_ctx);
-	} else if (ret) {
-		last_error_message = smb_get_krb5_error_message(context, ret, mem_ctx);
-		DEBUG(1, ("ads_keytab_verify_ticket: krb5_kt_start_seq_get failed (%s)\n", 
-			  last_error_message));
-	} else {
-		ret = KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN; /* Pick an error... */
-		last_error_message = "No principals in Keytab";
-		while (ret && (krb5_kt_next_entry(context, keytab, &kt_entry, &kt_cursor) == 0)) {
-			krb5_error_code upn_ret;
-			upn_ret = krb5_unparse_name(context, kt_entry.principal, &entry_princ_s);
-			if (upn_ret) {
-				last_error_message = smb_get_krb5_error_message(context, ret, mem_ctx);
-				DEBUG(1, ("ads_keytab_verify_ticket: krb5_unparse_name failed (%s)\n", 
-					  last_error_message));
-				ret = upn_ret;
-				break;
-			}
-			for (i = 0; i < ARRAY_SIZE(valid_princ_formats); i++) {
-				if (!strequal(entry_princ_s, valid_princ_formats[i])) {
-					continue;
-				}
-
-				number_matched_principals++;
-				*pp_tkt = NULL;
-				ret = krb5_rd_req_return_keyblock(context, auth_context, p_packet, 
-								  kt_entry.principal, keytab, 
-								  ap_req_options, pp_tkt, keyblock);
-				if (ret) {
-					last_error_message = smb_get_krb5_error_message(context, ret, mem_ctx);
-					DEBUG(10, ("ads_keytab_verify_ticket: krb5_rd_req(%s) failed: %s\n",
-						   entry_princ_s, last_error_message));
-				} else {
-					DEBUG(3,("ads_keytab_verify_ticket: krb5_rd_req succeeded for principal %s\n",
-						 entry_princ_s));
-					break;
-				}
-			}
-
-			/* Free the name we parsed. */
-			krb5_free_unparsed_name(context, entry_princ_s);
-			entry_princ_s = NULL;
-
-			/* Free the entry we just read. */
-			smb_krb5_kt_free_entry(context, &kt_entry);
-			ZERO_STRUCT(kt_entry);
-		}
-		krb5_kt_end_seq_get(context, keytab, &kt_cursor);
-	}
-
-	ZERO_STRUCT(kt_cursor);
-
-  out:
-
-	if (ret) {
-		if (!number_matched_principals) {
-			DEBUG(3, ("ads_keytab_verify_ticket: no keytab principals matched expected file service name.\n"));
-		} else {
-			DEBUG(3, ("ads_keytab_verify_ticket: krb5_rd_req failed for all %d matched keytab principals\n",
-				number_matched_principals));
-		}
-		DEBUG(3, ("ads_keytab_verify_ticket: last error: %s\n", last_error_message));
-	}
-
-	if (entry_princ_s) {
-		krb5_free_unparsed_name(context, entry_princ_s);
-	}
-
-	{
-		krb5_keytab_entry zero_kt_entry;
-		ZERO_STRUCT(zero_kt_entry);
-		if (memcmp(&zero_kt_entry, &kt_entry, sizeof(krb5_keytab_entry))) {
-			smb_krb5_kt_free_entry(context, &kt_entry);
-		}
-	}
-
-	{
-		krb5_kt_cursor zero_csr;
-		ZERO_STRUCT(zero_csr);
-		if ((memcmp(&kt_cursor, &zero_csr, sizeof(krb5_kt_cursor)) != 0) && keytab) {
-			krb5_kt_end_seq_get(context, keytab, &kt_cursor);
-		}
-	}
-
-	if (keytab) {
-		krb5_kt_close(context, keytab);
-	}
-
-	return ret;
-}
-
-/**********************************************************************************
  Verify an incoming ticket and parse out the principal name and 
  authorization_data if available.
 ***********************************************************************************/
@@ -221,7 +71,8 @@ static krb5_error_code ads_keytab_verify_ticket(TALLOC_CTX *mem_ctx, krb5_contex
  NTSTATUS ads_verify_ticket(TALLOC_CTX *mem_ctx, 
 			    struct smb_krb5_context *smb_krb5_context,
 			    krb5_auth_context *auth_context,
-			    const char *realm, const char *service, 
+			    struct cli_credentials *machine_account,
+			    const char *service, 
 			    const DATA_BLOB *enc_ticket, 
 			    krb5_ticket **tkt,
 			    DATA_BLOB *ap_rep,
@@ -229,32 +80,12 @@ static krb5_error_code ads_keytab_verify_ticket(TALLOC_CTX *mem_ctx, krb5_contex
 {
 	krb5_keyblock *local_keyblock;
 	krb5_data packet;
-	krb5_principal salt_princ;
 	int ret;
 	krb5_flags ap_req_options = 0;
+	krb5_principal server;
 
-	NTSTATUS creds_nt_status, status;
-	struct cli_credentials *machine_account;
+	struct keytab_container *keytab_container;
 
-	machine_account = cli_credentials_init(mem_ctx);
-	cli_credentials_set_conf(machine_account);
-	creds_nt_status = cli_credentials_set_machine_account(machine_account);
-	
-	if (!NT_STATUS_IS_OK(creds_nt_status)) {
-		DEBUG(3, ("Could not obtain machine account credentials from the local database\n"));
-		talloc_free(machine_account);
-		machine_account = NULL;
-	} else {
-		ret = salt_principal_from_credentials(mem_ctx, machine_account, 
-						      smb_krb5_context, 
-						      &salt_princ);
-		if (ret) {
-			DEBUG(1,("ads_verify_ticket: maksing salt principal failed (%s)\n",
-				 error_message(ret)));
-			return NT_STATUS_INTERNAL_ERROR;
-		}
-	}
-	
 	/* This whole process is far more complex than I would
            like. We have to go through all this to allow us to store
            the secret internally, instead of using /etc/krb5.keytab */
@@ -268,24 +99,18 @@ static krb5_error_code ads_keytab_verify_ticket(TALLOC_CTX *mem_ctx, krb5_contex
 	packet.length = enc_ticket->length;
 	packet.data = (krb5_pointer)enc_ticket->data;
 
-	ret = ads_keytab_verify_ticket(mem_ctx, smb_krb5_context->krb5_context, auth_context, 
-				       service, &packet, &ap_req_options, tkt, &local_keyblock);
-	if (ret && machine_account) {
-		krb5_keytab keytab;
-		krb5_principal server;
-		status = create_memory_keytab(mem_ctx, machine_account, smb_krb5_context, 
-					      &keytab);
-		if (!NT_STATUS_IS_OK(status)) {
-			return status;
-		}
-		ret = principal_from_credentials(mem_ctx, machine_account, smb_krb5_context, 
-						 &server);
-		if (ret == 0) {
-			ret = krb5_rd_req_return_keyblock(smb_krb5_context->krb5_context, auth_context, &packet,
-							  server,
-							  keytab, &ap_req_options, tkt,
-							  &local_keyblock);
-		}
+	ret = cli_credentials_get_keytab(machine_account, &keytab_container);
+	if (ret) {
+		return NT_STATUS_CANT_ACCESS_DOMAIN_INFO;
+	}
+
+	ret = principal_from_credentials(mem_ctx, machine_account, smb_krb5_context, 
+					 &server);
+	if (ret == 0) {
+		ret = krb5_rd_req_return_keyblock(smb_krb5_context->krb5_context, auth_context, &packet,
+						  server,
+						  keytab_container->keytab, &ap_req_options, tkt,
+						  &local_keyblock);
 	}
 
 	if (ret) {