source4/smb_server/smb2/negprot.c

   1 /*
   2    Unix SMB2 implementation.
   3
   4    Copyright (C) Andrew Bartlett        2001-2005
   5    Copyright (C) Stefan Metzmacher      2005
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "includes.h"
  22 #include "auth/credentials/credentials.h"
  23 #include "auth/auth.h"
  24 #include "auth/gensec/gensec.h"
  25 #include "libcli/raw/libcliraw.h"
  26 #include "libcli/raw/raw_proto.h"
  27 #include "libcli/smb2/smb2.h"
  28 #include "libcli/smb2/smb2_calls.h"
  29 #include "smb_server/smb_server.h"
  30 #include "smb_server/smb2/smb2_server.h"
  31 #include "smbd/service_stream.h"
  32 #include "param/param.h"
  33
  34 static NTSTATUS smb2srv_negprot_secblob(struct smb2srv_request *req, DATA_BLOB *_blob)
  35 {
  36         struct gensec_security *gensec_security;
  37         DATA_BLOB null_data_blob = data_blob(NULL, 0);
  38         DATA_BLOB blob;
  39         NTSTATUS nt_status;
  40         struct cli_credentials *server_credentials;
  41
  42         server_credentials = cli_credentials_init(req);
  43         if (!server_credentials) {
  44                 smbsrv_terminate_connection(req->smb_conn, "Failed to init server credentials\n");
  45                 return NT_STATUS_NO_MEMORY;
  46         }
  47
  48         cli_credentials_set_conf(server_credentials, req->smb_conn->lp_ctx);
  49         nt_status = cli_credentials_set_machine_account(server_credentials, req->smb_conn->lp_ctx);
  50         if (!NT_STATUS_IS_OK(nt_status)) {
  51                 DEBUG(10, ("Failed to obtain server credentials, perhaps a standalone server?: %s\n", nt_errstr(nt_status)));
  52                 talloc_free(server_credentials);
  53                 server_credentials = NULL;
  54         }
  55
  56         req->smb_conn->negotiate.server_credentials = talloc_steal(req->smb_conn, server_credentials);
  57
  58         nt_status = samba_server_gensec_start(req,
  59                                               req->smb_conn->connection->event.ctx,
  60                                               req->smb_conn->connection->msg_ctx,
  61                                               req->smb_conn->lp_ctx,
  62                                               server_credentials,
  63                                               "cifs",
  64                                               &gensec_security);
  65         if (!NT_STATUS_IS_OK(nt_status)) {
  66                 DEBUG(0, ("Failed to start GENSEC: %s\n", nt_errstr(nt_status)));
  67                 smbsrv_terminate_connection(req->smb_conn, "Failed to start GENSEC\n");
  68                 return nt_status;
  69         }
  70
  71         gensec_set_target_service(gensec_security, "cifs");
  72
  73         gensec_set_credentials(gensec_security, server_credentials);
  74
  75         nt_status = gensec_start_mech_by_oid(gensec_security, GENSEC_OID_SPNEGO);
  76         if (!NT_STATUS_IS_OK(nt_status)) {
  77                 DEBUG(0, ("Failed to start SPNEGO: %s\n", nt_errstr(nt_status)));
  78                 smbsrv_terminate_connection(req->smb_conn, "Failed to start SPNEGO\n");
  79                 return nt_status;
  80         }
  81
  82         nt_status = gensec_update(gensec_security, req, req->smb_conn->connection->event.ctx, null_data_blob, &blob);
  83         if (!NT_STATUS_IS_OK(nt_status) && !NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
  84                 DEBUG(0, ("Failed to get SPNEGO to give us the first token: %s\n", nt_errstr(nt_status)));
  85                 smbsrv_terminate_connection(req->smb_conn, "Failed to start SPNEGO - no first token\n");
  86                 return nt_status;
  87         }
  88
  89         *_blob = blob;
  90         return NT_STATUS_OK;
  91 }
  92
  93 static NTSTATUS smb2srv_negprot_backend(struct smb2srv_request *req, struct smb2_negprot *io)
  94 {
  95         NTSTATUS status;
  96         struct timeval current_time;
  97         struct timeval boot_time;
  98         uint16_t i;
  99         uint16_t dialect = 0;
 100         enum smb_signing_setting signing_setting;
 101         struct loadparm_context *lp_ctx = req->smb_conn->lp_ctx;
 102
 103         /* we only do one dialect for now */
 104         if (io->in.dialect_count < 1) {
 105                 return NT_STATUS_NOT_SUPPORTED;
 106         }
 107         for (i=0; i < io->in.dialect_count; i++) {
 108                 dialect = io->in.dialects[i];
 109                 if (dialect == SMB2_DIALECT_REVISION_202) {
 110                         break;
 111                 }
 112         }
 113         if (dialect != SMB2_DIALECT_REVISION_202) {
 114                 DEBUG(0,("Got unexpected SMB2 dialect %u\n", dialect));
 115                 return NT_STATUS_NOT_SUPPORTED;
 116         }
 117
 118         req->smb_conn->negotiate.protocol = PROTOCOL_SMB2_02;
 119
 120         current_time = timeval_current(); /* TODO: handle timezone?! */
 121         boot_time = timeval_current(); /* TODO: fix me */
 122
 123         ZERO_STRUCT(io->out);
 124
 125         signing_setting = lpcfg_server_signing(lp_ctx);
 126         if (signing_setting == SMB_SIGNING_DEFAULT) {
 127                 /*
 128                  * If we are a domain controller, SMB signing is
 129                  * really important, as it can prevent a number of
 130                  * attacks on communications between us and the
 131                  * clients
 132                  *
 133                  * However, it really sucks (no sendfile, CPU
 134                  * overhead) performance-wise when used on a
 135                  * file server, so disable it by default
 136                  * on non-DCs
 137                  */
 138
 139                 if (lpcfg_server_role(lp_ctx) >= ROLE_ACTIVE_DIRECTORY_DC) {
 140                         signing_setting = SMB_SIGNING_REQUIRED;
 141                 } else {
 142                         signing_setting = SMB_SIGNING_OFF;
 143                 }
 144         }
 145
 146         switch (signing_setting) {
 147         case SMB_SIGNING_DEFAULT:
 148                 smb_panic(__location__);
 149                 break;
 150         case SMB_SIGNING_OFF:
 151                 io->out.security_mode = 0;
 152                 break;
 153         case SMB_SIGNING_IF_REQUIRED:
 154                 io->out.security_mode = SMB2_NEGOTIATE_SIGNING_ENABLED;
 155                 break;
 156         case SMB_SIGNING_REQUIRED:
 157                 io->out.security_mode = SMB2_NEGOTIATE_SIGNING_ENABLED | SMB2_NEGOTIATE_SIGNING_REQUIRED;
 158                 /* force signing on immediately */
 159                 req->smb_conn->smb2_signing_required = true;
 160                 break;
 161         }
 162         io->out.dialect_revision   = dialect;
 163         io->out.capabilities       = 0;
 164         io->out.max_transact_size  = lpcfg_parm_ulong(req->smb_conn->lp_ctx, NULL,
 165                                                    "smb2", "max transaction size", 0x10000);
 166         io->out.max_read_size      = lpcfg_parm_ulong(req->smb_conn->lp_ctx, NULL,
 167                                                    "smb2", "max read size", 0x10000);
 168         io->out.max_write_size     = lpcfg_parm_ulong(req->smb_conn->lp_ctx, NULL,
 169                                                    "smb2", "max write size", 0x10000);
 170         io->out.system_time        = timeval_to_nttime(&current_time);
 171         io->out.server_start_time  = timeval_to_nttime(&boot_time);
 172         io->out.reserved2          = 0;
 173         status = smb2srv_negprot_secblob(req, &io->out.secblob);
 174         NT_STATUS_NOT_OK_RETURN(status);
 175
 176         return NT_STATUS_OK;
 177 }
 178
 179 static void smb2srv_negprot_send(struct smb2srv_request *req, struct smb2_negprot *io)
 180 {
 181         NTSTATUS status;
 182
 183         if (NT_STATUS_IS_ERR(req->status)) {
 184                 smb2srv_send_error(req, req->status); /* TODO: is this correct? */
 185                 return;
 186         }
 187
 188         status = smb2srv_setup_reply(req, 0x40, true, io->out.secblob.length);
 189         if (!NT_STATUS_IS_OK(status)) {
 190                 smbsrv_terminate_connection(req->smb_conn, nt_errstr(status));
 191                 talloc_free(req);
 192                 return;
 193         }
 194
 195         SSVAL(req->out.body, 0x02, io->out.security_mode);
 196         SIVAL(req->out.body, 0x04, io->out.dialect_revision);
 197         SIVAL(req->out.body, 0x06, io->out.reserved);
 198         status = smbcli_push_guid(req->out.body, 0x08, &io->out.server_guid);
 199         if (!NT_STATUS_IS_OK(status)) {
 200                 smbsrv_terminate_connection(req->smb_conn, nt_errstr(status));
 201                 talloc_free(req);
 202                 return;
 203         }
 204         SIVAL(req->out.body, 0x18, io->out.capabilities);
 205         SIVAL(req->out.body, 0x1C, io->out.max_transact_size);
 206         SIVAL(req->out.body, 0x20, io->out.max_read_size);
 207         SIVAL(req->out.body, 0x24, io->out.max_write_size);
 208         push_nttime(req->out.body, 0x28, io->out.system_time);
 209         push_nttime(req->out.body, 0x30, io->out.server_start_time);
 210         SIVAL(req->out.body, 0x3C, io->out.reserved2);
 211         status = smb2_push_o16s16_blob(&req->out, 0x38, io->out.secblob);
 212         if (!NT_STATUS_IS_OK(status)) {
 213                 smbsrv_terminate_connection(req->smb_conn, nt_errstr(status));
 214                 talloc_free(req);
 215                 return;
 216         }
 217
 218         smb2srv_send_reply(req);
 219 }
 220
 221 void smb2srv_negprot_recv(struct smb2srv_request *req)
 222 {
 223         struct smb2_negprot *io;
 224         int i;
 225
 226         if (req->in.body_size < 0x26) {
 227                 smbsrv_terminate_connection(req->smb_conn, "Bad body size in SMB2 negprot");
 228                 return;
 229         }
 230
 231         io = talloc(req, struct smb2_negprot);
 232         if (!io) {
 233                 smbsrv_terminate_connection(req->smb_conn, nt_errstr(NT_STATUS_NO_MEMORY));
 234                 talloc_free(req);
 235                 return;
 236         }
 237
 238         io->in.dialect_count = SVAL(req->in.body, 0x02);
 239         io->in.security_mode = SVAL(req->in.body, 0x04);
 240         io->in.reserved      = SVAL(req->in.body, 0x06);
 241         io->in.capabilities  = IVAL(req->in.body, 0x08);
 242         req->status = smbcli_pull_guid(req->in.body, 0xC, &io->in.client_guid);
 243         if (!NT_STATUS_IS_OK(req->status)) {
 244                 smbsrv_terminate_connection(req->smb_conn, "Bad GUID in SMB2 negprot");
 245                 talloc_free(req);
 246                 return;
 247         }
 248         io->in.start_time = smbcli_pull_nttime(req->in.body, 0x1C);
 249
 250         io->in.dialects = talloc_array(req, uint16_t, io->in.dialect_count);
 251         if (io->in.dialects == NULL) {
 252                 smbsrv_terminate_connection(req->smb_conn, nt_errstr(NT_STATUS_NO_MEMORY));
 253                 talloc_free(req);
 254                 return;
 255         }
 256         for (i=0;i<io->in.dialect_count;i++) {
 257                 io->in.dialects[i] = SVAL(req->in.body, 0x24+i*2);
 258         }
 259
 260         req->status = smb2srv_negprot_backend(req, io);
 261
 262         if (req->control_flags & SMB2SRV_REQ_CTRL_FLAG_NOT_REPLY) {
 263                 talloc_free(req);
 264                 return;
 265         }
 266         smb2srv_negprot_send(req, io);
 267 }
 268
 269 /*
 270  * reply to a SMB negprot request with dialect "SMB 2.002"
 271  */
 272 void smb2srv_reply_smb_negprot(struct smbsrv_request *smb_req)
 273 {
 274         struct smb2srv_request *req;
 275         uint32_t body_fixed_size = 0x26;
 276
 277         req = talloc_zero(smb_req->smb_conn, struct smb2srv_request);
 278         if (!req) goto nomem;
 279         req->smb_conn           = smb_req->smb_conn;
 280         req->request_time       = smb_req->request_time;
 281         talloc_steal(req, smb_req);
 282
 283         req->in.size      = NBT_HDR_SIZE+SMB2_HDR_BODY+body_fixed_size;
 284         req->in.allocated = req->in.size;
 285         req->in.buffer    = talloc_array(req, uint8_t, req->in.allocated);
 286         if (!req->in.buffer) goto nomem;
 287         req->in.hdr       = req->in.buffer + NBT_HDR_SIZE;
 288         req->in.body      = req->in.hdr + SMB2_HDR_BODY;
 289         req->in.body_size = body_fixed_size;
 290         req->in.dynamic   = NULL;
 291
 292         smb2srv_setup_bufinfo(req);
 293
 294         SIVAL(req->in.hdr, 0,                           SMB2_MAGIC);
 295         SSVAL(req->in.hdr, SMB2_HDR_LENGTH,             SMB2_HDR_BODY);
 296         SSVAL(req->in.hdr, SMB2_HDR_EPOCH,              0);
 297         SIVAL(req->in.hdr, SMB2_HDR_STATUS,             0);
 298         SSVAL(req->in.hdr, SMB2_HDR_OPCODE,             SMB2_OP_NEGPROT);
 299         SSVAL(req->in.hdr, SMB2_HDR_CREDIT,             0);
 300         SIVAL(req->in.hdr, SMB2_HDR_FLAGS,              0);
 301         SIVAL(req->in.hdr, SMB2_HDR_NEXT_COMMAND,       0);
 302         SBVAL(req->in.hdr, SMB2_HDR_MESSAGE_ID,         0);
 303         SIVAL(req->in.hdr, SMB2_HDR_PID,                0);
 304         SIVAL(req->in.hdr, SMB2_HDR_TID,                0);
 305         SBVAL(req->in.hdr, SMB2_HDR_SESSION_ID,         0);
 306         memset(req->in.hdr+SMB2_HDR_SIGNATURE, 0, 16);
 307
 308         /* this seems to be a bug, they use 0x24 but the length is 0x26 */
 309         SSVAL(req->in.body, 0x00, 0x24);
 310
 311         SSVAL(req->in.body, 0x02, 1);
 312         memset(req->in.body+0x04, 0, 32);
 313         SSVAL(req->in.body, 0x24, SMB2_DIALECT_REVISION_202);
 314
 315         smb2srv_negprot_recv(req);
 316         return;
 317 nomem:
 318         smbsrv_terminate_connection(smb_req->smb_conn, nt_errstr(NT_STATUS_NO_MEMORY));
 319         talloc_free(req);
 320         return;
 321 }