r7993: Further work on the Krb5 PAC.

We now generate the PAC, and can verifiy both our own PAC and the PAC
from Win2k3.

This commit adds the PAC generation code, spits out the code to get
the information we need from the NETLOGON server back into a auth/
helper function, and adds a number of glue functions.

In the process of building the PAC generation code, some hints in the
Microsoft PAC specification shed light on other parts of the code, and
the updates to samr.idl and netlogon.idl come from those hints.

Also in this commit:

The Heimdal build package has been split up, so as to only link the
KDC with smbd, not the client utils.

To enable the PAC to be veified with gensec_krb5 (which isn't quite
dead yet), the keyblock has been passed back to the calling layer.

Andrew Bartlett
(This used to be commit e2015671c2f7501f832ff402873ffe6e53b89466)

1 files changed, 167 insertions, 15 deletions

diff --git a/source4/auth/kerberos/kerberos_pac.c b/source4/auth/kerberos/kerberos_pac.c
index 9d57245798..e1d05b9949 100644
--- a/source4/auth/kerberos/kerberos_pac.c
+++ b/source4/auth/kerberos/kerberos_pac.c
@@ -28,16 +28,16 @@
 #include "system/kerberos.h"
 #include "system/time.h"
 #include "system/network.h"
+#include "auth/auth.h"
 #include "auth/kerberos/kerberos.h"
 #include "librpc/gen_ndr/ndr_krb5pac.h"
 #include "auth/auth.h"
 
-static NTSTATUS kerberos_pac_checksum(TALLOC_CTX *mem_ctx, 
-				      DATA_BLOB pac_data,
-				      struct PAC_SIGNATURE_DATA *sig,
-				      struct smb_krb5_context *smb_krb5_context,
-				      krb5_keyblock *keyblock,
-				      uint32_t keyusage)
+static NTSTATUS check_pac_checksum(TALLOC_CTX *mem_ctx, 
+				   DATA_BLOB pac_data,
+				   struct PAC_SIGNATURE_DATA *sig,
+				   krb5_context context,
+				   krb5_keyblock *keyblock)
 {
 	krb5_error_code ret;
 	krb5_crypto crypto;
@@ -48,7 +48,7 @@ static NTSTATUS kerberos_pac_checksum(TALLOC_CTX *mem_ctx,
 	cksum.checksum.data	= sig->signature;
 
 
-	ret = krb5_crypto_init(smb_krb5_context->krb5_context,
+	ret = krb5_crypto_init(context,
 			       keyblock,
 			       0,
 			       &crypto);
@@ -56,7 +56,7 @@ static NTSTATUS kerberos_pac_checksum(TALLOC_CTX *mem_ctx,
 		DEBUG(0,("krb5_crypto_init() failed\n"));
 		return NT_STATUS_FOOBAR;
 	}
-	ret = krb5_verify_checksum(smb_krb5_context->krb5_context,
+	ret = krb5_verify_checksum(context,
 				   crypto,
 				   KRB5_KU_OTHER_CKSUM,
 				   pac_data.data,
@@ -64,10 +64,10 @@ static NTSTATUS kerberos_pac_checksum(TALLOC_CTX *mem_ctx,
 				   &cksum);
 	if (ret) {
 		DEBUG(2, ("PAC Verification failed: %s\n", 
-			  smb_get_krb5_error_message(smb_krb5_context->krb5_context, ret, mem_ctx)));
+			  smb_get_krb5_error_message(context, ret, mem_ctx)));
 	}
 
-	krb5_crypto_destroy(smb_krb5_context->krb5_context, crypto);
+	krb5_crypto_destroy(context, crypto);
 
 	if (ret) {
 		return NT_STATUS_ACCESS_DENIED;
@@ -92,6 +92,8 @@ static NTSTATUS kerberos_pac_checksum(TALLOC_CTX *mem_ctx,
 	DATA_BLOB modified_pac_blob = data_blob_talloc(mem_ctx, blob.data, blob.length);
 	int i;
 
+	file_save("/tmp/pac.in", blob.data, blob.length);
+
 	status = ndr_pull_struct_blob(&blob, mem_ctx, &pac_data,
 					(ndr_pull_flags_fn_t)ndr_pull_PAC_DATA);
 	if (!NT_STATUS_IS_OK(status)) {
@@ -127,7 +129,7 @@ static NTSTATUS kerberos_pac_checksum(TALLOC_CTX *mem_ctx,
 				kdc_sig_ptr = &pac_data.buffers[i].info->kdc_cksum;
 				kdc_sig = pac_data.buffers[i].info->kdc_cksum;
 				break;
-			case PAC_TYPE_UNKNOWN_10:
+			case PAC_TYPE_LOGON_NAME:
 				break;
 			default:
 				break;
@@ -154,11 +156,13 @@ static NTSTATUS kerberos_pac_checksum(TALLOC_CTX *mem_ctx,
 	memset(&modified_pac_blob.data[modified_pac_blob.length - 44],
 	       '\0', 16);
 
-	/* verify by servie_key */
-	status = kerberos_pac_checksum(mem_ctx, 
-				       modified_pac_blob, &srv_sig, 
-				       smb_krb5_context, keyblock, 0);
+	file_save("/tmp/pac.in.blanked", modified_pac_blob.data, modified_pac_blob.length);
 
+	/* verify by service_key */
+	status = check_pac_checksum(mem_ctx, 
+				    modified_pac_blob, &srv_sig, 
+				    smb_krb5_context->krb5_context, keyblock);
+	
 	if (!NT_STATUS_IS_OK(status)) {
 		return status;
 	}
@@ -170,3 +174,151 @@ static NTSTATUS kerberos_pac_checksum(TALLOC_CTX *mem_ctx,
 	return status;
 }
 
+static krb5_error_code make_pac_checksum(TALLOC_CTX *mem_ctx, 
+					 DATA_BLOB pac_data,
+					 struct PAC_SIGNATURE_DATA *sig,
+					 krb5_context context,
+					 krb5_keyblock *keyblock)
+{
+	krb5_error_code ret;
+	krb5_crypto crypto;
+	Checksum cksum;
+
+
+	ret = krb5_crypto_init(context,
+			       keyblock,
+			       0,
+			       &crypto);
+	if (ret) {
+		DEBUG(0,("krb5_crypto_init() failed\n"));
+		return ret;
+	}
+	ret = krb5_create_checksum(context,
+				   crypto,
+				   KRB5_KU_OTHER_CKSUM,
+				   0,
+				   pac_data.data,
+				   pac_data.length,
+				   &cksum);
+	if (ret) {
+		DEBUG(2, ("PAC Verification failed: %s\n", 
+			  smb_get_krb5_error_message(context, ret, mem_ctx)));
+	}
+
+	krb5_crypto_destroy(context, crypto);
+
+	if (ret) {
+		return ret;
+	}
+
+	sig->type = cksum.cksumtype;
+	if (cksum.checksum.length == sizeof(sig->signature)) {
+		memcpy(sig->signature, cksum.checksum.data, sizeof(sig->signature));
+	}
+
+	return 0;
+}
+
+ krb5_error_code kerberos_encode_pac(TALLOC_CTX *mem_ctx,
+				     struct auth_serversupplied_info *server_info,
+				     krb5_context context,
+				     krb5_keyblock *keyblock,
+				     krb5_data *pac)
+{
+	NTSTATUS nt_status;
+	DATA_BLOB tmp_blob = data_blob(NULL, 0);
+	krb5_error_code ret;
+	struct PAC_DATA *pac_data = talloc(mem_ctx, struct PAC_DATA);
+	struct netr_SamBaseInfo *sam;
+	struct timeval tv = timeval_current();
+
+	if (!pac_data) {
+		return ENOMEM;
+	}
+
+	pac_data->num_buffers = 4;
+	pac_data->version = 0;
+
+	pac_data->buffers = talloc_array(pac_data, 
+					 struct PAC_BUFFER,
+					 pac_data->num_buffers);
+
+	if (!pac_data->buffers) {
+		talloc_free(pac_data);
+		return ENOMEM;
+	}
+	pac_data->buffers[0].type = PAC_TYPE_LOGON_INFO;
+	pac_data->buffers[0].info = talloc_zero(pac_data->buffers,
+						union PAC_INFO);
+
+	nt_status = auth_convert_server_info_sambaseinfo(pac_data->buffers[0].info,
+							 server_info, &sam);
+	if (!NT_STATUS_IS_OK(nt_status)) {
+		DEBUG(1, ("Getting Samba info failed: %s\n", nt_errstr(nt_status)));
+		talloc_free(pac_data);
+		return EINVAL;
+	}
+
+	pac_data->buffers[0].info->logon_info.info3.base = *sam;
+
+	pac_data->buffers[1].type = PAC_TYPE_LOGON_NAME;
+	pac_data->buffers[1].info = talloc_zero(pac_data->buffers,
+						union PAC_INFO);
+	pac_data->buffers[1].info->logon_name.account_name
+		= server_info->account_name;
+	pac_data->buffers[1].info->logon_name.logon_time
+		= timeval_to_nttime(&tv);
+
+	pac_data->buffers[2].type = PAC_TYPE_KDC_CHECKSUM;
+	pac_data->buffers[2].info = talloc_zero(pac_data->buffers,
+						union PAC_INFO);
+
+	pac_data->buffers[3].type = PAC_TYPE_SRV_CHECKSUM;
+	pac_data->buffers[3].info = talloc_zero(pac_data->buffers,
+						union PAC_INFO);
+	
+	/* First, just get the keytypes filled in (and lengths right, eventually) */
+	ret = make_pac_checksum(mem_ctx, tmp_blob, &pac_data->buffers[2].info->srv_cksum,
+				context, keyblock);
+	if (ret) {
+		DEBUG(2, ("making PAC checksum failed: %s\n", 
+			  smb_get_krb5_error_message(context, ret, mem_ctx)));
+		talloc_free(pac_data);
+		return ret;
+	}
+
+	/* But wipe out the actual signatures */
+	ZERO_STRUCT(pac_data->buffers[2].info->kdc_cksum.signature);
+	ZERO_STRUCT(pac_data->buffers[3].info->srv_cksum.signature);
+	
+	nt_status = ndr_push_struct_blob(&tmp_blob, mem_ctx, pac_data,
+					 (ndr_push_flags_fn_t)ndr_push_PAC_DATA);
+	if (!NT_STATUS_IS_OK(nt_status)) {
+		DEBUG(1, ("PAC push failed: %s\n", nt_errstr(nt_status)));
+		talloc_free(pac_data);
+		return EINVAL;
+	}
+
+	file_save("/tmp/pac.out.blank", tmp_blob.data, tmp_blob.length);
+
+	/* Then sign the result of the previous push, where the sig was zero'ed out */
+	ret = make_pac_checksum(mem_ctx, tmp_blob, &pac_data->buffers[3].info->srv_cksum,
+				context, keyblock);
+
+	/* And push it out to the world.  This relies on determanistic pointer values */
+	nt_status = ndr_push_struct_blob(&tmp_blob, mem_ctx, pac_data,
+					 (ndr_push_flags_fn_t)ndr_push_PAC_DATA);
+	if (!NT_STATUS_IS_OK(nt_status)) {
+		DEBUG(1, ("PAC push failed: %s\n", nt_errstr(nt_status)));
+		talloc_free(pac_data);
+		return EINVAL;
+	}
+
+	file_save("/tmp/pac.out.signed", tmp_blob.data, tmp_blob.length);
+
+	ret = krb5_data_copy(pac, tmp_blob.data, tmp_blob.length);
+	
+	talloc_free(pac_data);
+	return ret;
+}
+