Implement NETLOGON PAC verfication on the server-side

This is implemented by means of a message to the KDC, to avoid having
to link most of the KDC into netlogon.

Andrew Bartlett

diff --git a/source/auth/kerberos/kerberos_pac.c b/source/auth/kerberos/kerberos_pac.c
index 9ebace32cb5b188675a9821177b75150be95772f..2943e05b18e85c754e1263040546aa0897c3bbfb 100644 (file)
--- a/source/auth/kerberos/kerberos_pac.c
+++ b/source/auth/kerberos/kerberos_pac.c
@@ -32,11 +32,11 @@
 #include "auth/auth_sam_reply.h"
 #include "param/param.h"
 
-static krb5_error_code check_pac_checksum(TALLOC_CTX *mem_ctx, 
-                                         DATA_BLOB pac_data,
-                                         struct PAC_SIGNATURE_DATA *sig,
-                                         krb5_context context,
-                                         const krb5_keyblock *keyblock)
+krb5_error_code check_pac_checksum(TALLOC_CTX *mem_ctx, 
+                                  DATA_BLOB pac_data,
+                                  struct PAC_SIGNATURE_DATA *sig,
+                                  krb5_context context,
+                                  const krb5_keyblock *keyblock)
 {
        krb5_error_code ret;
        krb5_crypto crypto;

diff --git a/source/kdc/kdc.c b/source/kdc/kdc.c
index dfd62c55a47dff1e87a948dfba67aae0bb33255b..5d7b48afe4be9f5b1e3082446ed10699b5c0ddce 100644 (file)
--- a/source/kdc/kdc.c
+++ b/source/kdc/kdc.c
@@ -33,9 +33,12 @@
 #include "lib/messaging/irpc.h"
 #include "lib/stream/packet.h"
 #include "librpc/gen_ndr/samr.h"
+#include "librpc/gen_ndr/ndr_irpc.h"
+#include "librpc/gen_ndr/ndr_krb5pac.h"
 #include "lib/socket/netif.h"
 #include "param/param.h"
 #include "kdc/kdc.h"
+#include "librpc/gen_ndr/ndr_misc.h"
 
 
 /* Disgusting hack to get a mem_ctx and lp_ctx into the hdb plugin, when 
@@ -555,6 +558,108 @@ static struct krb5plugin_windc_ftable windc_plugin_table = {
 };
 
 
+static NTSTATUS kdc_check_generic_kerberos(struct irpc_message *msg, 
+                                struct kdc_check_generic_kerberos *r)
+{
+       struct PAC_Validate pac_validate;
+       DATA_BLOB srv_sig;
+       struct PAC_SIGNATURE_DATA kdc_sig;
+       struct kdc_server *kdc = talloc_get_type(msg->private, struct kdc_server);
+       enum ndr_err_code ndr_err;
+       krb5_enctype etype;
+       int ret;
+       hdb_entry_ex ent;
+       krb5_principal principal;
+       krb5_keyblock keyblock;
+       Key *key;
+
+       /* There is no reply to this request */
+       r->out.generic_reply = data_blob(NULL, 0);
+
+       ndr_err = ndr_pull_struct_blob(&r->in.generic_request, msg, 
+                                      lp_iconv_convenience(kdc->task->lp_ctx), 
+                                      &pac_validate,
+                                      (ndr_pull_flags_fn_t)ndr_pull_PAC_Validate);
+       if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
+               return NT_STATUS_INVALID_PARAMETER;
+       }
+       
+#if 0
+       /* Windows does not check this */
+       if (pac_validate.MessageType != 3) {
+               /* We don't implement any other message types - such as certificate validation - yet */
+               return NT_STATUS_INVALID_PARAMETER;
+       }
+#endif 
+       if (pac_validate.ChecksumAndSignature.length != (pac_validate.ChecksumLength + pac_validate.SignatureLength)
+           || pac_validate.ChecksumAndSignature.length < pac_validate.ChecksumLength
+           || pac_validate.ChecksumAndSignature.length < pac_validate.SignatureLength ) {
+               return NT_STATUS_INVALID_PARAMETER;
+       }
+       
+       srv_sig = data_blob_const(pac_validate.ChecksumAndSignature.data, 
+                                 pac_validate.ChecksumLength);
+       
+       if (pac_validate.SignatureType == CKSUMTYPE_HMAC_MD5) {
+               etype = ETYPE_ARCFOUR_HMAC_MD5;
+       } else {
+               ret = krb5_cksumtype_to_enctype(kdc->smb_krb5_context->krb5_context, pac_validate.SignatureType,
+                                               &etype);
+               if (ret != 0) {
+                       return NT_STATUS_LOGON_FAILURE;
+               }
+       }
+
+       ret = krb5_make_principal(kdc->smb_krb5_context->krb5_context, &principal, 
+                                 lp_realm(kdc->task->lp_ctx), 
+                                 "krbtgt", lp_realm(kdc->task->lp_ctx), 
+                                 NULL);
+
+       if (ret != 0) {
+               return NT_STATUS_NO_MEMORY;
+       }
+
+       ret = kdc->config->db[0]->hdb_fetch(kdc->smb_krb5_context->krb5_context, 
+                                           kdc->config->db[0],
+                                           principal,
+                                           HDB_F_GET_KRBTGT | HDB_F_DECRYPT,
+                                           &ent);
+
+       if (ret != 0) {
+               hdb_free_entry(kdc->smb_krb5_context->krb5_context, &ent);
+               krb5_free_principal(kdc->smb_krb5_context->krb5_context, principal);
+       
+               return NT_STATUS_LOGON_FAILURE;
+       }
+       
+       ret = hdb_enctype2key(kdc->smb_krb5_context->krb5_context, &ent.entry, etype, &key);
+
+       if (ret != 0) {
+               hdb_free_entry(kdc->smb_krb5_context->krb5_context, &ent);
+               krb5_free_principal(kdc->smb_krb5_context->krb5_context, principal);
+               return NT_STATUS_LOGON_FAILURE;
+       }
+
+       keyblock = key->key;
+       
+       kdc_sig.type = pac_validate.SignatureType;
+       kdc_sig.signature = data_blob_const(&pac_validate.ChecksumAndSignature.data[pac_validate.ChecksumLength],
+                                           pac_validate.SignatureLength);
+       ret = check_pac_checksum(msg, srv_sig, &kdc_sig, 
+                          kdc->smb_krb5_context->krb5_context, &keyblock);
+
+       hdb_free_entry(kdc->smb_krb5_context->krb5_context, &ent);
+       krb5_free_principal(kdc->smb_krb5_context->krb5_context, principal);
+
+       if (ret != 0) {
+               return NT_STATUS_LOGON_FAILURE;
+       }
+       
+       return NT_STATUS_OK;
+}
+
+
+
 /*
   startup the kdc task
 */
@@ -656,6 +761,13 @@ static void kdc_task_init(struct task_server *task)
                return;
        }
 
+       status = IRPC_REGISTER(task->msg_ctx, irpc, KDC_CHECK_GENERIC_KERBEROS, 
+                              kdc_check_generic_kerberos, kdc);
+       if (!NT_STATUS_IS_OK(status)) {
+               task_server_terminate(task, "nbtd failed to setup monitoring");
+               return;
+       }
+
        irpc_add_name(task->msg_ctx, "kdc_server");
 }
 

diff --git a/source/librpc/idl/irpc.idl b/source/librpc/idl/irpc.idl
index 2c659aa785002b363f6b5fcd758fa40b0d0d8542..e3ea7e55e1a8770e29edfe6a51616d1e980987f6 100644 (file)
--- a/source/librpc/idl/irpc.idl
+++ b/source/librpc/idl/irpc.idl
@@ -52,6 +52,9 @@ import "misc.idl", "security.idl", "nbt.idl";
                [out,switch_is(level)] nbtd_info info
                );
 
+       /* Send a GetDCName from the privilaged port (owned by nbtd),
+        * and await a reply */
+
        void nbtd_getdcname(
                [in] astring domainname,
                [in] astring ip_address,
@@ -78,6 +81,20 @@ import "misc.idl", "security.idl", "nbt.idl";
                [in] nbtd_proxy_wins_addr addrs[num_addrs]
                );
 
+       /*
+         Generic Kerberos package call (on the NETLOGON pipe, as a SamLogon)
+
+         The normal use for this call is to check the PAC signature in the KDC
+         
+         The KDC has the routines to check this, so it is easier to
+         proxy the request over by IRPC than set up the environment
+        */
+
+       void kdc_check_generic_kerberos(
+               [in] DATA_BLOB generic_request,
+               [out] DATA_BLOB generic_reply
+               );
+
        /******************************************************
          management calls for the smb server
        ******************************************************/

diff --git a/source/librpc/idl/krb5pac.idl b/source/librpc/idl/krb5pac.idl
index dcee280150dbf5313996e6208296640894cc01c7..bddba04165171fb023c5afbf1ef1a0743ba864c6 100644 (file)
--- a/source/librpc/idl/krb5pac.idl
+++ b/source/librpc/idl/krb5pac.idl
@@ -105,7 +105,7 @@ interface krb5pac
        typedef [public] struct {
                [value(NETLOGON_GENERIC_KRB5_PAC_VALIDATE)] uint32 MessageType;
                uint32 ChecksumLength;
-               uint32 SignatureType;
+               int32 SignatureType;
                uint32 SignatureLength;
                [flag(NDR_REMAINING)] DATA_BLOB ChecksumAndSignature;
        } PAC_Validate;

diff --git a/source/rpc_server/netlogon/dcerpc_netlogon.c b/source/rpc_server/netlogon/dcerpc_netlogon.c
index 5672d29cb2852845fa2ea8353756b6a5fd8fecf4..36ac650b08a8f1cf7880378a0220753f33b6653a 100644 (file)
--- a/source/rpc_server/netlogon/dcerpc_netlogon.c
+++ b/source/rpc_server/netlogon/dcerpc_netlogon.c
@@ -34,6 +34,8 @@
 #include "auth/gensec/schannel_state.h"
 #include "libcli/security/security.h"
 #include "param/param.h"
+#include "lib/messaging/irpc.h"
+#include "librpc/gen_ndr/ndr_irpc.h"
 
 struct server_pipe_state {
        struct netr_Credential client_challenge;
@@ -496,41 +498,37 @@ static NTSTATUS dcesrv_netr_LogonSamLogon_base(struct dcesrv_call_state *dce_cal
                        return NT_STATUS_INVALID_PARAMETER;
                }
 
-               if (strcmp(r->in.logon.generic->package_name.string, "Kerberos")) {
-                       struct PAC_Validate pac_validate;
-                       DATA_BLOB srv_sig;
-                       struct PAC_SIGNATURE_DATA kdc_sig;
-                       DATA_BLOB pac_validate_blob = data_blob_const(r->in.logon.generic->data, 
-                                                                     r->in.logon.generic->length);
-                       ndr_err = ndr_pull_struct_blob(&pac_validate_blob, mem_ctx, 
-                                                      lp_iconv_convenience(dce_call->conn->dce_ctx->lp_ctx), 
-                                                      &pac_validate,
-                                                      (ndr_pull_flags_fn_t)ndr_pull_PAC_Validate);
-                       if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
-                               return NT_STATUS_INVALID_PARAMETER;
-                       }
+               if (strcmp(r->in.logon.generic->package_name.string, "Kerberos") == 0) {
+                       NTSTATUS status;
+                       struct server_id *kdc;
+                       struct kdc_check_generic_kerberos check;
+                       struct netr_GenericInfo2 *generic = talloc_zero(mem_ctx, struct netr_GenericInfo2);
+                       NT_STATUS_HAVE_NO_MEMORY(generic);
+                       r->out.authoritative = 1;
+                       
+                       /* TODO: Describe and deal with these flags */
+                       r->out.flags = 0;
 
-                       if (pac_validate->MessageType != 3) {
-                               /* We don't implement any other message types - such as certificate validation - yet */
-                               return NT_STATUS_INVALID_PARAMETER;
+                       r->out.validation.generic = generic;
+       
+                       kdc = irpc_servers_byname(dce_call->msg_ctx, mem_ctx, "kdc_server");
+                       if ((kdc == NULL) || (kdc[0].id == 0)) {
+                               return NT_STATUS_NO_LOGON_SERVERS;
                        }
                        
-                       if (pac_validate->ChecksumAndSignature.length != (pac_validate->ChecksumLength + pac_validate->SignatureLength)
-                           || pac_validate->ChecksumAndSignature.length < pac_validate->ChecksumLength
-                           || pac_validate->ChecksumAndSignature.length < pac_validate->SignatureLength ) {
-                               return NT_STATUS_INVALID_PARAMETER;
+                       check.in.generic_request = 
+                               data_blob_const(r->in.logon.generic->data,
+                                               r->in.logon.generic->length);   
+                       
+                       status = irpc_call(dce_call->msg_ctx, kdc[0],
+                                          &ndr_table_irpc, NDR_KDC_CHECK_GENERIC_KERBEROS,
+                                          &check, mem_ctx);
+                       if (!NT_STATUS_IS_OK(status)) {
+                               return status;
                        }
-
-                       srv_sig = data_blob_const(pac_validate->ChecksumAndSignature.data, 
-                                                 pac_validate->ChecksumLength);
-
-                       kdc_sig.type = pac_validate->SignatureType;
-                       kdc_sig.signature = data_blob_const(&pac_validate->ChecksumAndSignature.data[pac_validate->ChecksumLength],
-                                                           pac_validate->SignatureLength);
-                       check_pac_checksum(mem_ctx, srv_sig, &kdc_sig, 
-                                          context, keyblock);
-                                          
-
+                       generic->length = check.out.generic_reply.length;
+                       generic->data = check.out.generic_reply.data;
+                       return NT_STATUS_OK;
                }
 
                /* Until we get an implemetnation of these other packages */

diff --git a/source/samba4-skip b/source/samba4-skip
index 35b274f63f69f6f83bb821b3ad4a5d2c1ff968c9..b1313adea0cf63918bcc38503379fbd4028145f4 100644 (file)
--- a/source/samba4-skip
+++ b/source/samba4-skip
@@ -41,7 +41,6 @@ ntvfs.cifs.raw.context
 ntvfs.cifs.raw.qfileinfo.ipc
 rpc.dssync
 rpc.samsync
-rpc.pac                                                        # Not finished yet
 ldap.uptodatevector                                    # Segfaults
 rpc.remact                                                     # Not provided by Samba 4
 rpc.oxidresolve                                                # Not provided by Samba 4