s3:libsmb: handle the smb signing states the same in the krb5 and ntlmssp cases

SMB signing works the same regardless of the used auth mech.

We need to start with the temp signing ("BSRSPYL ")
and the session setup response with NT_STATUS_OK
is the first signed packet.

Now we set the krb5 session key if we got the NT_STATUS_OK
from the server and then recheck the packet.

All this is needed to make the fallback from krb5 to
ntlmssp possible. This commit also resets the cli->vuid
value to 0, if the krb5 auth didn't succeed. Otherwise
the server handles NTLMSSP packets as krb5 packets.

The restructuring of the SMB signing code is needed to
make sure the krb5 code only starts the signing engine
on success. Otherwise the NTLMSSP fallback could not initialize
the signing engine (again).

metze

1 files changed, 35 insertions, 16 deletions

diff --git a/source3/libsmb/cliconnect.c b/source3/libsmb/cliconnect.c
index 6ddc249c04..bf0d270bab 100644
--- a/source3/libsmb/cliconnect.c
+++ b/source3/libsmb/cliconnect.c
@@ -535,7 +535,7 @@ static DATA_BLOB cli_session_setup_blob_receive(struct cli_state *cli)
 
 #define BASE_SESSSETUP_BLOB_PACKET_SIZE (35 + 24 + 22)
 
-static bool cli_session_setup_blob(struct cli_state *cli, DATA_BLOB blob, DATA_BLOB session_key_krb5)
+static bool cli_session_setup_blob(struct cli_state *cli, DATA_BLOB blob)
 {
 	int32 remaining = blob.length;
 	int32 cur = 0;
@@ -559,13 +559,8 @@ static bool cli_session_setup_blob(struct cli_state *cli, DATA_BLOB blob, DATA_B
 			send_blob.length = max_blob_size;
 			remaining -= max_blob_size;
 		} else {
-			DATA_BLOB null_blob = data_blob_null;
-
 			send_blob.length = remaining; 
                         remaining = 0;
-
-			/* This is the last packet in the sequence - turn signing on. */
-			cli_simple_set_signing(cli, session_key_krb5, null_blob); 
 		}
 
 		send_blob.data =  &blob.data[cur];
@@ -613,8 +608,11 @@ static ADS_STATUS cli_session_setup_kerberos(struct cli_state *cli, const char *
 {
 	DATA_BLOB negTokenTarg;
 	DATA_BLOB session_key_krb5;
+	NTSTATUS nt_status;
 	int rc;
 
+	cli_temp_set_signing(cli);
+
 	DEBUG(2,("Doing kerberos session setup\n"));
 
 	/* generate the encapsulated kerberos5 ticket */
@@ -630,23 +628,44 @@ static ADS_STATUS cli_session_setup_kerberos(struct cli_state *cli, const char *
 	file_save("negTokenTarg.dat", negTokenTarg.data, negTokenTarg.length);
 #endif
 
-	if (!cli_session_setup_blob(cli, negTokenTarg, session_key_krb5)) {
-		data_blob_free(&negTokenTarg);
-		data_blob_free(&session_key_krb5);
-		return ADS_ERROR_NT(cli_nt_error(cli));
+	if (!cli_session_setup_blob(cli, negTokenTarg)) {
+		nt_status = cli_nt_error(cli);
+		goto nt_error;
+	}
+
+	if (cli_is_error(cli)) {
+		nt_status = cli_nt_error(cli);
+		if (NT_STATUS_IS_OK(nt_status)) {
+			nt_status = NT_STATUS_UNSUCCESSFUL;
+		}
+		goto nt_error;
 	}
 
 	cli_set_session_key(cli, session_key_krb5);
 
+	if (cli_simple_set_signing(
+		    cli, session_key_krb5, data_blob_null)) {
+
+		/* 'resign' the last message, so we get the right sequence numbers
+		   for checking the first reply from the server */
+		cli_calculate_sign_mac(cli, cli->outbuf);
+
+		if (!cli_check_sign_mac(cli, cli->inbuf)) {
+			nt_status = NT_STATUS_ACCESS_DENIED;
+			goto nt_error;
+		}
+	}
+
 	data_blob_free(&negTokenTarg);
 	data_blob_free(&session_key_krb5);
 
-	if (cli_is_error(cli)) {
-		if (NT_STATUS_IS_OK(cli_nt_error(cli))) {
-			return ADS_ERROR_NT(NT_STATUS_UNSUCCESSFUL);
-		}
-	} 
-	return ADS_ERROR_NT(cli_nt_error(cli));
+	return ADS_ERROR_NT(NT_STATUS_OK);
+
+nt_error:
+	data_blob_free(&negTokenTarg);
+	data_blob_free(&session_key_krb5);
+	cli->vuid = 0;
+	return ADS_ERROR_NT(nt_status);
 }
 #endif	/* HAVE_KRB5 */