CVE-2015-5370: s4:librpc/rpc: finally verify the server uses the expected auth_{type...
[sfrench/samba-autobuild/.git] / source4 / librpc / rpc / dcerpc_auth.c
index 0966b7033855968acdd8069dd1b7aa4fcbd8fb9a..d617b07e07c810e8b9b27568df308ef703e008c5 100644 (file)
@@ -4,12 +4,12 @@
    Generic Authentication Interface
 
    Copyright (C) Andrew Tridgell 2003
-   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004
-
+   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004-2005
+   Copyright (C) Stefan Metzmacher 2004
    
    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
+   the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.
    
    This program is distributed in the hope that it will be useful,
    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.
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
 #include "includes.h"
+#include <tevent.h>
+#include "libcli/composite/composite.h"
+#include "auth/gensec/gensec.h"
+#include "librpc/rpc/dcerpc.h"
+#include "librpc/rpc/dcerpc_proto.h"
+#include "param/param.h"
 
 /*
-  do a non-athenticated dcerpc bind
+  return the rpc syntax and transfer syntax given the pipe uuid and version
 */
-NTSTATUS dcerpc_bind_auth_none(struct dcerpc_pipe *p,
-                              const char *uuid, uint_t version)
+static NTSTATUS dcerpc_init_syntaxes(const struct ndr_interface_table *table,
+                                    uint32_t pipe_flags,
+                                    struct ndr_syntax_id *syntax,
+                                    struct ndr_syntax_id *transfer_syntax)
 {
-       TALLOC_CTX *mem_ctx;
-       NTSTATUS status;
+       syntax->uuid = table->syntax_id.uuid;
+       syntax->if_version = table->syntax_id.if_version;
+
+       if (pipe_flags & DCERPC_NDR64) {
+               *transfer_syntax = ndr_transfer_syntax_ndr64;
+       } else {
+               *transfer_syntax = ndr_transfer_syntax_ndr;
+       }
+
+       return NT_STATUS_OK;
+}
 
-       mem_ctx = talloc_init("dcerpc_bind_auth_ntlm");
-       if (!mem_ctx) {
-               return NT_STATUS_NO_MEMORY;
+
+/*
+  Send request to do a non-authenticated dcerpc bind
+*/
+static void dcerpc_bind_auth_none_done(struct tevent_req *subreq);
+
+struct composite_context *dcerpc_bind_auth_none_send(TALLOC_CTX *mem_ctx,
+                                                    struct dcerpc_pipe *p,
+                                                    const struct ndr_interface_table *table)
+{
+       struct ndr_syntax_id syntax;
+       struct ndr_syntax_id transfer_syntax;
+
+       struct composite_context *c;
+       struct tevent_req *subreq;
+
+       c = composite_create(mem_ctx, p->conn->event_ctx);
+       if (c == NULL) return NULL;
+
+       c->status = dcerpc_init_syntaxes(table, p->conn->flags,
+                                        &syntax, &transfer_syntax);
+       if (!NT_STATUS_IS_OK(c->status)) {
+               DEBUG(2,("Invalid uuid string in "
+                        "dcerpc_bind_auth_none_send\n"));
+               composite_error(c, c->status);
+               return c;
        }
 
-       status = dcerpc_bind_byuuid(p, mem_ctx, uuid, version);
-       talloc_destroy(mem_ctx);
+       subreq = dcerpc_bind_send(mem_ctx, p->conn->event_ctx, p,
+                                 &syntax, &transfer_syntax);
+       if (composite_nomem(subreq, c)) return c;
+       tevent_req_set_callback(subreq, dcerpc_bind_auth_none_done, c);
 
-       return status;
+       return c;
 }
 
-NTSTATUS dcerpc_bind_auth3(struct dcerpc_pipe *p, uint8_t auth_type, uint8_t auth_level,
-                         const char *uuid, uint_t version)
+static void dcerpc_bind_auth_none_done(struct tevent_req *subreq)
 {
-       NTSTATUS status;
-       TALLOC_CTX *mem_ctx;
-       DATA_BLOB credentials;
-       DATA_BLOB null_data_blob = data_blob(NULL, 0);
+       struct composite_context *ctx =
+               tevent_req_callback_data(subreq,
+               struct composite_context);
 
-       mem_ctx = talloc_init("dcerpc_bind_auth");
-       if (!mem_ctx) {
-               return NT_STATUS_NO_MEMORY;
-       }
-       
-       if (!p->security_state.generic_state) {
-               status = gensec_client_start(&p->security_state.generic_state);
-               if (!NT_STATUS_IS_OK(status)) {
-                       return status;
-               }
+       ctx->status = dcerpc_bind_recv(subreq);
+       TALLOC_FREE(subreq);
+       if (!composite_is_ok(ctx)) return;
 
-               status = gensec_start_mech_by_authtype(p->security_state.generic_state, auth_type, auth_level);
+       composite_done(ctx);
+}
 
-               if (!NT_STATUS_IS_OK(status)) {
-                       return status;
-               }
-       }
+/*
+  Receive result of a non-authenticated dcerpc bind
+*/
+NTSTATUS dcerpc_bind_auth_none_recv(struct composite_context *ctx)
+{
+       NTSTATUS result = composite_wait(ctx);
+       TALLOC_FREE(ctx);
+       return result;
+}
 
-       p->security_state.auth_info = talloc(p, sizeof(*p->security_state.auth_info));
-       if (!p->security_state.auth_info) {
-               status = NT_STATUS_NO_MEMORY;
-               goto done;
+
+/*
+  Perform sync non-authenticated dcerpc bind
+*/
+_PUBLIC_ NTSTATUS dcerpc_bind_auth_none(struct dcerpc_pipe *p,
+                              const struct ndr_interface_table *table)
+{
+       struct composite_context *ctx;
+
+       ctx = dcerpc_bind_auth_none_send(p, p, table);
+       return dcerpc_bind_auth_none_recv(ctx);
+}
+
+
+struct bind_auth_state {
+       struct dcerpc_pipe *pipe;
+       struct dcerpc_auth out_auth_info;
+       struct dcerpc_auth in_auth_info;
+       bool more_processing;   /* Is there anything more to do after the
+                                * first bind itself received? */
+};
+
+static void bind_auth_recv_alter(struct tevent_req *subreq);
+
+static void bind_auth_next_step(struct composite_context *c)
+{
+       struct bind_auth_state *state;
+       struct dcecli_security *sec;
+       struct tevent_req *subreq;
+       bool more_processing = false;
+
+       state = talloc_get_type(c->private_data, struct bind_auth_state);
+       sec = &state->pipe->conn->security_state;
+
+       if (state->in_auth_info.auth_type != sec->auth_type) {
+               composite_error(c, NT_STATUS_RPC_PROTOCOL_ERROR);
+               return;
        }
 
-       p->security_state.auth_info->auth_type = auth_type;
-       p->security_state.auth_info->auth_level = auth_level;
-       p->security_state.auth_info->auth_pad_length = 0;
-       p->security_state.auth_info->auth_reserved = 0;
-       p->security_state.auth_info->auth_context_id = random();
-       p->security_state.auth_info->credentials = null_data_blob;
+       if (state->in_auth_info.auth_level != sec->auth_level) {
+               composite_error(c, NT_STATUS_RPC_PROTOCOL_ERROR);
+               return;
+       }
 
-       status = gensec_update(p->security_state.generic_state, mem_ctx,
-                              null_data_blob,
-                              &credentials);
-       
-       if (!NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
-               goto done;
+       if (state->in_auth_info.auth_context_id != sec->auth_context_id) {
+               composite_error(c, NT_STATUS_RPC_PROTOCOL_ERROR);
+               return;
        }
 
-       p->security_state.auth_info->credentials = credentials;
+       state->out_auth_info = (struct dcerpc_auth) {
+               .auth_type = sec->auth_type,
+               .auth_level = sec->auth_level,
+               .auth_context_id = sec->auth_context_id,
+       };
+
+       /* The status value here, from GENSEC is vital to the security
+        * of the system.  Even if the other end accepts, if GENSEC
+        * claims 'MORE_PROCESSING_REQUIRED' then you must keep
+        * feeding it blobs, or else the remote host/attacker might
+        * avoid mutal authentication requirements.
+        *
+        * Likewise, you must not feed GENSEC too much (after the OK),
+        * it doesn't like that either
+        */
+
+       state->pipe->inhibit_timeout_processing = true;
+       state->pipe->timed_out = false;
+
+       c->status = gensec_update_ev(sec->generic_state, state,
+                                 state->pipe->conn->event_ctx,
+                                 state->in_auth_info.credentials,
+                                 &state->out_auth_info.credentials);
+       if (state->pipe->timed_out) {
+               composite_error(c, NT_STATUS_IO_TIMEOUT);
+               return;
+       }
+       state->pipe->inhibit_timeout_processing = false;
 
-       status = dcerpc_bind_byuuid(p, mem_ctx, uuid, version);
-       if (!NT_STATUS_IS_OK(status)) {
-               goto done;
+       if (NT_STATUS_EQUAL(c->status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
+               more_processing = true;
+               c->status = NT_STATUS_OK;
        }
 
-       status = gensec_update(p->security_state.generic_state, mem_ctx,
-                              p->security_state.auth_info->credentials,
-                              &credentials);
+       if (!composite_is_ok(c)) return;
 
-       if (!NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
-               goto done;
+       if (state->out_auth_info.credentials.length == 0) {
+               composite_done(c);
+               return;
        }
 
-       p->security_state.auth_info->credentials = credentials;
-       
-       status = dcerpc_auth3(p, mem_ctx);
-done:
-       talloc_destroy(mem_ctx);
+       state->in_auth_info = (struct dcerpc_auth) {
+               .auth_type = DCERPC_AUTH_TYPE_NONE,
+       };
+       sec->tmp_auth_info.in = &state->in_auth_info;
+       sec->tmp_auth_info.mem = state;
+       sec->tmp_auth_info.out = &state->out_auth_info;
 
-       if (!NT_STATUS_IS_OK(status)) {
-               ZERO_STRUCT(p->security_state);
-       } else {
-               /* Authenticated connections use the generic session key */
-               p->security_state.session_key = dcerpc_generic_session_key;
+       if (!more_processing) {
+               /* NO reply expected, so just send it */
+               c->status = dcerpc_auth3(state->pipe, state);
+               if (!composite_is_ok(c)) return;
+
+               composite_done(c);
+               return;
        }
 
-       return status;
+       /* We are demanding a reply, so use a request that will get us one */
+
+       subreq = dcerpc_alter_context_send(state, state->pipe->conn->event_ctx,
+                                          state->pipe,
+                                          &state->pipe->syntax,
+                                          &state->pipe->transfer_syntax);
+       if (composite_nomem(subreq, c)) return;
+       tevent_req_set_callback(subreq, bind_auth_recv_alter, c);
+}
+
+
+static void bind_auth_recv_alter(struct tevent_req *subreq)
+{
+       struct composite_context *c =
+               tevent_req_callback_data(subreq,
+               struct composite_context);
+       struct bind_auth_state *state = talloc_get_type(c->private_data,
+                                                       struct bind_auth_state);
+       struct dcecli_security *sec = &state->pipe->conn->security_state;
+
+       ZERO_STRUCT(sec->tmp_auth_info);
+
+       c->status = dcerpc_alter_context_recv(subreq);
+       TALLOC_FREE(subreq);
+       if (!composite_is_ok(c)) return;
+
+       bind_auth_next_step(c);
 }
 
-NTSTATUS dcerpc_bind_alter(struct dcerpc_pipe *p, uint8_t auth_type, uint8_t auth_level,
-                         const char *uuid, uint_t version)
+
+static void bind_auth_recv_bindreply(struct tevent_req *subreq)
 {
-       NTSTATUS status;
-       TALLOC_CTX *mem_ctx;
-       DATA_BLOB credentials;
-       DATA_BLOB null_data_blob = data_blob(NULL, 0);
+       struct composite_context *c =
+               tevent_req_callback_data(subreq,
+               struct composite_context);
+       struct bind_auth_state *state = talloc_get_type(c->private_data,
+                                                       struct bind_auth_state);
+       struct dcecli_security *sec = &state->pipe->conn->security_state;
 
-       mem_ctx = talloc_init("dcerpc_bind_auth");
-       if (!mem_ctx) {
-               return NT_STATUS_NO_MEMORY;
-       }
-       
-       if (!p->security_state.generic_state) {
-               status = gensec_client_start(&p->security_state.generic_state);
-               if (!NT_STATUS_IS_OK(status)) {
-                       return status;
-               }
+       ZERO_STRUCT(sec->tmp_auth_info);
 
-               status = gensec_start_mech_by_authtype(p->security_state.generic_state, 
-                                                      auth_type, auth_level);
+       c->status = dcerpc_bind_recv(subreq);
+       TALLOC_FREE(subreq);
+       if (!composite_is_ok(c)) return;
 
-               if (!NT_STATUS_IS_OK(status)) {
-                       return status;
-               }
+       if (state->pipe->conn->flags & DCERPC_HEADER_SIGNING) {
+               gensec_want_feature(sec->generic_state, GENSEC_FEATURE_SIGN_PKT_HEADER);
        }
 
-       p->security_state.auth_info = talloc(p, sizeof(*p->security_state.auth_info));
-       if (!p->security_state.auth_info) {
-               status = NT_STATUS_NO_MEMORY;
-               goto done;
+       if (!state->more_processing) {
+               /* The first gensec_update has not requested a second run, so
+                * we're done here. */
+               composite_done(c);
+               return;
        }
 
-       p->security_state.auth_info->auth_type = auth_type;
-       p->security_state.auth_info->auth_level = auth_level;
-       p->security_state.auth_info->auth_pad_length = 0;
-       p->security_state.auth_info->auth_reserved = 0;
-       p->security_state.auth_info->auth_context_id = random();
-       p->security_state.auth_info->credentials = null_data_blob;
+       bind_auth_next_step(c);
+}
 
-       status = gensec_update(p->security_state.generic_state, mem_ctx,
-                              null_data_blob,
-                              &credentials);
-       
-       if (!NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
-               goto done;
+
+/**
+   Bind to a DCE/RPC pipe, send async request
+   @param mem_ctx TALLOC_CTX for the allocation of the composite_context
+   @param p The dcerpc_pipe to bind (must already be connected)
+   @param table The interface table to use (the DCE/RPC bind both selects and interface and authenticates)
+   @param credentials The credentials of the account to connect with 
+   @param auth_type Select the authentication scheme to use
+   @param auth_level Chooses between unprotected (connect), signed or sealed
+   @param service The service (used by Kerberos to select the service principal to contact)
+   @retval A composite context describing the partial state of the bind
+*/
+
+struct composite_context *dcerpc_bind_auth_send(TALLOC_CTX *mem_ctx,
+                                               struct dcerpc_pipe *p,
+                                               const struct ndr_interface_table *table,
+                                               struct cli_credentials *credentials,
+                                               struct gensec_settings *gensec_settings,
+                                               uint8_t auth_type, uint8_t auth_level,
+                                               const char *service)
+{
+       struct composite_context *c;
+       struct bind_auth_state *state;
+       struct dcecli_security *sec;
+       struct tevent_req *subreq;
+       struct ndr_syntax_id syntax, transfer_syntax;
+       const char *target_principal = NULL;
+
+       /* composite context allocation and setup */
+       c = composite_create(mem_ctx, p->conn->event_ctx);
+       if (c == NULL) return NULL;
+
+       state = talloc(c, struct bind_auth_state);
+       if (composite_nomem(state, c)) return c;
+       c->private_data = state;
+
+       state->pipe = p;
+
+       c->status = dcerpc_init_syntaxes(table, p->conn->flags,
+                                        &syntax,
+                                        &transfer_syntax);
+       if (!composite_is_ok(c)) return c;
+
+       sec = &p->conn->security_state;
+
+       c->status = gensec_client_start(p, &sec->generic_state,
+                                       gensec_settings);
+       if (!NT_STATUS_IS_OK(c->status)) {
+               DEBUG(1, ("Failed to start GENSEC client mode: %s\n",
+                         nt_errstr(c->status)));
+               composite_error(c, c->status);
+               return c;
        }
 
-       p->security_state.auth_info->credentials = credentials;
+       c->status = gensec_set_credentials(sec->generic_state, credentials);
+       if (!NT_STATUS_IS_OK(c->status)) {
+               DEBUG(1, ("Failed to set GENSEC client credentials: %s\n",
+                         nt_errstr(c->status)));
+               composite_error(c, c->status);
+               return c;
+       }
 
-       status = dcerpc_bind_byuuid(p, mem_ctx, uuid, version);
-       if (!NT_STATUS_IS_OK(status)) {
-               goto done;
+       c->status = gensec_set_target_hostname(sec->generic_state,
+                                              dcerpc_server_name(p));
+       if (!NT_STATUS_IS_OK(c->status)) {
+               DEBUG(1, ("Failed to set GENSEC target hostname: %s\n", 
+                         nt_errstr(c->status)));
+               composite_error(c, c->status);
+               return c;
        }
 
-       while(1) {
-               status = gensec_update(p->security_state.generic_state, mem_ctx,
-                              p->security_state.auth_info->credentials,
-                              &credentials);
+       if (service != NULL) {
+               c->status = gensec_set_target_service(sec->generic_state,
+                                                     service);
+               if (!NT_STATUS_IS_OK(c->status)) {
+                       DEBUG(1, ("Failed to set GENSEC target service: %s\n",
+                                 nt_errstr(c->status)));
+                       composite_error(c, c->status);
+                       return c;
+               }
+       }
 
-               if (!NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
-                       goto done;
+       if (p->binding != NULL) {
+               target_principal = dcerpc_binding_get_string_option(p->binding,
+                                                       "target_principal");
+       }
+       if (target_principal != NULL) {
+               c->status = gensec_set_target_principal(sec->generic_state,
+                                                       target_principal);
+               if (!NT_STATUS_IS_OK(c->status)) {
+                       DEBUG(1, ("Failed to set GENSEC target principal to %s: %s\n",
+                                 target_principal, nt_errstr(c->status)));
+                       composite_error(c, c->status);
+                       return c;
                }
+       }
+
+       c->status = gensec_start_mech_by_authtype(sec->generic_state,
+                                                 auth_type, auth_level);
+       if (!NT_STATUS_IS_OK(c->status)) {
+               DEBUG(1, ("Failed to start GENSEC client mechanism %s: %s\n",
+                         gensec_get_name_by_authtype(sec->generic_state, auth_type),
+                         nt_errstr(c->status)));
+               composite_error(c, c->status);
+               return c;
+       }
 
-               p->security_state.auth_info->credentials = credentials;
+       sec->auth_type = auth_type;
+       sec->auth_level = auth_level,
+       /*
+        * We use auth_context_id = 1 as some older
+        * Samba versions (<= 4.2.3) use that value hardcoded
+        * in a response.
+        */
+       sec->auth_context_id = 1;
+
+       state->out_auth_info = (struct dcerpc_auth) {
+               .auth_type = sec->auth_type,
+               .auth_level = sec->auth_level,
+               .auth_context_id = sec->auth_context_id,
+       };
+
+       /* The status value here, from GENSEC is vital to the security
+        * of the system.  Even if the other end accepts, if GENSEC
+        * claims 'MORE_PROCESSING_REQUIRED' then you must keep
+        * feeding it blobs, or else the remote host/attacker might
+        * avoid mutal authentication requirements.
+        *
+        * Likewise, you must not feed GENSEC too much (after the OK),
+        * it doesn't like that either
+        */
+
+       state->pipe->inhibit_timeout_processing = true;
+       state->pipe->timed_out = false;
+       c->status = gensec_update_ev(sec->generic_state, state,
+                                 p->conn->event_ctx,
+                                 data_blob_null,
+                                 &state->out_auth_info.credentials);
+       if (state->pipe->timed_out) {
+               composite_error(c, NT_STATUS_IO_TIMEOUT);
+               return c;
+       }
+       state->pipe->inhibit_timeout_processing = false;
+
+       if (!NT_STATUS_IS_OK(c->status) &&
+           !NT_STATUS_EQUAL(c->status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
+               composite_error(c, c->status);
+               return c;
+       }
 
-               status = dcerpc_alter(p, mem_ctx);
-               if (!NT_STATUS_IS_OK(status)) {
-                       goto done;
+       state->more_processing = NT_STATUS_EQUAL(c->status,
+                                                NT_STATUS_MORE_PROCESSING_REQUIRED);
+
+       if (state->out_auth_info.credentials.length == 0) {
+               composite_done(c);
+               return c;
+       }
+
+       if (gensec_have_feature(sec->generic_state, GENSEC_FEATURE_SIGN_PKT_HEADER)) {
+               if (sec->auth_level >= DCERPC_AUTH_LEVEL_INTEGRITY) {
+                       state->pipe->conn->flags |= DCERPC_PROPOSE_HEADER_SIGNING;
                }
        }
 
-done:
-       talloc_destroy(mem_ctx);
+       state->in_auth_info = (struct dcerpc_auth) {
+               .auth_type = DCERPC_AUTH_TYPE_NONE,
+       };
+       sec->tmp_auth_info.in = &state->in_auth_info;
+       sec->tmp_auth_info.mem = state;
+       sec->tmp_auth_info.out = &state->out_auth_info;
+
+       /* The first request always is a dcerpc_bind. The subsequent ones
+        * depend on gensec results */
+       subreq = dcerpc_bind_send(state, p->conn->event_ctx, p,
+                                 &syntax, &transfer_syntax);
+       if (composite_nomem(subreq, c)) return c;
+       tevent_req_set_callback(subreq, bind_auth_recv_bindreply, c);
+
+       return c;
+}
 
-       if (!NT_STATUS_IS_OK(status)) {
-               ZERO_STRUCT(p->security_state);
-       } else {
-               /* Authenticated connections use the generic session key */
-               p->security_state.session_key = dcerpc_generic_session_key;
+
+/**
+   Bind to a DCE/RPC pipe, receive result
+   @param creq A composite context describing state of async call
+   @retval NTSTATUS code
+*/
+
+NTSTATUS dcerpc_bind_auth_recv(struct composite_context *creq)
+{
+       NTSTATUS result = composite_wait(creq);
+       struct bind_auth_state *state = talloc_get_type(creq->private_data,
+                                                       struct bind_auth_state);
+
+       if (NT_STATUS_IS_OK(result)) {
+               /*
+                 after a successful authenticated bind the session
+                 key reverts to the generic session key
+               */
+               state->pipe->conn->security_state.session_key = dcerpc_generic_session_key;
        }
+       
+       talloc_free(creq);
+       return result;
+}
+
 
-       return status;
+/**
+   Perform a GENSEC authenticated bind to a DCE/RPC pipe, sync
+   @param p The dcerpc_pipe to bind (must already be connected)
+   @param table The interface table to use (the DCE/RPC bind both selects and interface and authenticates)
+   @param credentials The credentials of the account to connect with 
+   @param auth_type Select the authentication scheme to use
+   @param auth_level Chooses between unprotected (connect), signed or sealed
+   @param service The service (used by Kerberos to select the service principal to contact)
+   @retval NTSTATUS status code
+*/
+
+_PUBLIC_ NTSTATUS dcerpc_bind_auth(struct dcerpc_pipe *p,
+                         const struct ndr_interface_table *table,
+                         struct cli_credentials *credentials,
+                         struct gensec_settings *gensec_settings,
+                         uint8_t auth_type, uint8_t auth_level,
+                         const char *service)
+{
+       struct composite_context *creq;
+       creq = dcerpc_bind_auth_send(p, p, table, credentials, gensec_settings,
+                                    auth_type, auth_level, service);
+       return dcerpc_bind_auth_recv(creq);
 }