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 "samba/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 =
  43                 cli_credentials_init_server(req, req->smb_conn->lp_ctx);
  44         if (server_credentials == NULL) {
  45                 DBG_DEBUG("Failed to obtain server credentials, "
  46                           "perhaps a standalone server?\n");
  47                 /*
  48                  * Create anon server credentials for for the
  49                  * spoolss.notify test.
  50                  */
  51                 server_credentials = cli_credentials_init_anon(req);
  52                 if (server_credentials == NULL) {
  53                         smbsrv_terminate_connection(req->smb_conn,
  54                                 "Failed to init server credentials\n");
  55                         return NT_STATUS_NO_MEMORY;
  56                 }
  57         }
  58
  59         req->smb_conn->negotiate.server_credentials = talloc_steal(req->smb_conn, server_credentials);
  60
  61         nt_status = samba_server_gensec_start(req,
  62                                               req->smb_conn->connection->event.ctx,
  63                                               req->smb_conn->connection->msg_ctx,
  64                                               req->smb_conn->lp_ctx,
  65                                               server_credentials,
  66                                               "cifs",
  67                                               &gensec_security);
  68         if (!NT_STATUS_IS_OK(nt_status)) {
  69                 DEBUG(0, ("Failed to start GENSEC: %s\n", nt_errstr(nt_status)));
  70                 smbsrv_terminate_connection(req->smb_conn, "Failed to start GENSEC\n");
  71                 return nt_status;
  72         }
  73
  74         gensec_set_target_service(gensec_security, "cifs");
  75
  76         gensec_set_credentials(gensec_security, server_credentials);
  77
  78         nt_status = gensec_start_mech_by_oid(gensec_security, GENSEC_OID_SPNEGO);
  79         if (!NT_STATUS_IS_OK(nt_status)) {
  80                 DEBUG(0, ("Failed to start SPNEGO: %s\n", nt_errstr(nt_status)));
  81                 smbsrv_terminate_connection(req->smb_conn, "Failed to start SPNEGO\n");
  82                 return nt_status;
  83         }
  84
  85         nt_status = gensec_update(gensec_security, req,
  86                                   null_data_blob, &blob);
  87         if (!NT_STATUS_IS_OK(nt_status) && !NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
  88                 DEBUG(0, ("Failed to get SPNEGO to give us the first token: %s\n", nt_errstr(nt_status)));
  89                 smbsrv_terminate_connection(req->smb_conn, "Failed to start SPNEGO - no first token\n");
  90                 return nt_status;
  91         }
  92
  93         *_blob = blob;
  94         return NT_STATUS_OK;
  95 }
  96
  97 static NTSTATUS smb2srv_negprot_backend(struct smb2srv_request *req, struct smb2_negprot *io)
  98 {
  99         NTSTATUS status;
 100         struct timeval current_time;
 101         struct timeval boot_time;
 102         uint16_t i;
 103         uint16_t dialect = 0;
 104         enum smb_signing_setting signing_setting;
 105         struct loadparm_context *lp_ctx = req->smb_conn->lp_ctx;
 106
 107         /* we only do one dialect for now */
 108         if (io->in.dialect_count < 1) {
 109                 return NT_STATUS_NOT_SUPPORTED;
 110         }
 111         for (i=0; i < io->in.dialect_count; i++) {
 112                 dialect = io->in.dialects[i];
 113                 if (dialect == SMB2_DIALECT_REVISION_202) {
 114                         break;
 115                 }
 116         }
 117         if (dialect != SMB2_DIALECT_REVISION_202) {
 118                 DEBUG(0,("Got unexpected SMB2 dialect %u\n", dialect));
 119                 return NT_STATUS_NOT_SUPPORTED;
 120         }
 121
 122         req->smb_conn->negotiate.protocol = PROTOCOL_SMB2_02;
 123
 124         current_time = timeval_current(); /* TODO: handle timezone?! */
 125         boot_time = timeval_current(); /* TODO: fix me */
 126
 127         ZERO_STRUCT(io->out);
 128
 129         signing_setting = lpcfg_server_signing(lp_ctx);
 130         if (signing_setting == SMB_SIGNING_DEFAULT) {
 131                 /*
 132                  * If we are a domain controller, SMB signing is
 133                  * really important, as it can prevent a number of
 134                  * attacks on communications between us and the
 135                  * clients
 136                  *
 137                  * However, it really sucks (no sendfile, CPU
 138                  * overhead) performance-wise when used on a
 139                  * file server, so disable it by default
 140                  * on non-DCs
 141                  */
 142
 143                 if (lpcfg_server_role(lp_ctx) >= ROLE_ACTIVE_DIRECTORY_DC) {
 144                         signing_setting = SMB_SIGNING_REQUIRED;
 145                 } else {
 146                         signing_setting = SMB_SIGNING_OFF;
 147                 }
 148         }
 149
 150         switch (signing_setting) {
 151         case SMB_SIGNING_DEFAULT:
 152         case SMB_SIGNING_IPC_DEFAULT:
 153                 smb_panic(__location__);
 154                 break;
 155         case SMB_SIGNING_OFF:
 156                 io->out.security_mode = 0;
 157                 break;
 158         case SMB_SIGNING_DESIRED:
 159         case SMB_SIGNING_IF_REQUIRED:
 160                 io->out.security_mode = SMB2_NEGOTIATE_SIGNING_ENABLED;
 161                 break;
 162         case SMB_SIGNING_REQUIRED:
 163                 io->out.security_mode = SMB2_NEGOTIATE_SIGNING_ENABLED | SMB2_NEGOTIATE_SIGNING_REQUIRED;
 164                 /* force signing on immediately */
 165                 req->smb_conn->smb2_signing_required = true;
 166                 break;
 167         }
 168         io->out.dialect_revision   = dialect;
 169         io->out.capabilities       = 0;
 170         io->out.max_transact_size  = lpcfg_parm_ulong(req->smb_conn->lp_ctx, NULL,
 171                                                    "smb2", "max transaction size", 0x10000);
 172         io->out.max_read_size      = lpcfg_parm_ulong(req->smb_conn->lp_ctx, NULL,
 173                                                    "smb2", "max read size", 0x10000);
 174         io->out.max_write_size     = lpcfg_parm_ulong(req->smb_conn->lp_ctx, NULL,
 175                                                    "smb2", "max write size", 0x10000);
 176         io->out.system_time        = timeval_to_nttime(&current_time);
 177         io->out.server_start_time  = timeval_to_nttime(&boot_time);
 178         io->out.reserved2          = 0;
 179         status = smb2srv_negprot_secblob(req, &io->out.secblob);
 180         NT_STATUS_NOT_OK_RETURN(status);
 181
 182         return NT_STATUS_OK;
 183 }
 184
 185 static void smb2srv_negprot_send(struct smb2srv_request *req, struct smb2_negprot *io)
 186 {
 187         NTSTATUS status;
 188
 189         if (NT_STATUS_IS_ERR(req->status)) {
 190                 smb2srv_send_error(req, req->status); /* TODO: is this correct? */
 191                 return;
 192         }
 193
 194         status = smb2srv_setup_reply(req, 0x40, true, io->out.secblob.length);
 195         if (!NT_STATUS_IS_OK(status)) {
 196                 smbsrv_terminate_connection(req->smb_conn, nt_errstr(status));
 197                 talloc_free(req);
 198                 return;
 199         }
 200
 201         SSVAL(req->out.body, 0x02, io->out.security_mode);
 202         SIVAL(req->out.body, 0x04, io->out.dialect_revision);
 203         SIVAL(req->out.body, 0x06, io->out.reserved);
 204         status = smbcli_push_guid(req->out.body, 0x08, &io->out.server_guid);
 205         if (!NT_STATUS_IS_OK(status)) {
 206                 smbsrv_terminate_connection(req->smb_conn, nt_errstr(status));
 207                 talloc_free(req);
 208                 return;
 209         }
 210         SIVAL(req->out.body, 0x18, io->out.capabilities);
 211         SIVAL(req->out.body, 0x1C, io->out.max_transact_size);
 212         SIVAL(req->out.body, 0x20, io->out.max_read_size);
 213         SIVAL(req->out.body, 0x24, io->out.max_write_size);
 214         push_nttime(req->out.body, 0x28, io->out.system_time);
 215         push_nttime(req->out.body, 0x30, io->out.server_start_time);
 216         SIVAL(req->out.body, 0x3C, io->out.reserved2);
 217         status = smb2_push_o16s16_blob(&req->out, 0x38, io->out.secblob);
 218         if (!NT_STATUS_IS_OK(status)) {
 219                 smbsrv_terminate_connection(req->smb_conn, nt_errstr(status));
 220                 talloc_free(req);
 221                 return;
 222         }
 223
 224         smb2srv_send_reply(req);
 225 }
 226
 227 void smb2srv_negprot_recv(struct smb2srv_request *req)
 228 {
 229         struct smb2_negprot *io;
 230         int i;
 231
 232         if (req->in.body_size < 0x26) {
 233                 smbsrv_terminate_connection(req->smb_conn, "Bad body size in SMB2 negprot");
 234                 return;
 235         }
 236
 237         io = talloc(req, struct smb2_negprot);
 238         if (!io) {
 239                 smbsrv_terminate_connection(req->smb_conn, nt_errstr(NT_STATUS_NO_MEMORY));
 240                 talloc_free(req);
 241                 return;
 242         }
 243
 244         io->in.dialect_count = SVAL(req->in.body, 0x02);
 245         io->in.security_mode = SVAL(req->in.body, 0x04);
 246         io->in.reserved      = SVAL(req->in.body, 0x06);
 247         io->in.capabilities  = IVAL(req->in.body, 0x08);
 248         req->status = smbcli_pull_guid(req->in.body, 0xC, &io->in.client_guid);
 249         if (!NT_STATUS_IS_OK(req->status)) {
 250                 smbsrv_terminate_connection(req->smb_conn, "Bad GUID in SMB2 negprot");
 251                 talloc_free(req);
 252                 return;
 253         }
 254         io->in.start_time = smbcli_pull_nttime(req->in.body, 0x1C);
 255
 256         io->in.dialects = talloc_array(req, uint16_t, io->in.dialect_count);
 257         if (io->in.dialects == NULL) {
 258                 smbsrv_terminate_connection(req->smb_conn, nt_errstr(NT_STATUS_NO_MEMORY));
 259                 talloc_free(req);
 260                 return;
 261         }
 262         for (i=0;i<io->in.dialect_count;i++) {
 263                 io->in.dialects[i] = SVAL(req->in.body, 0x24+i*2);
 264         }
 265
 266         req->status = smb2srv_negprot_backend(req, io);
 267
 268         if (req->control_flags & SMB2SRV_REQ_CTRL_FLAG_NOT_REPLY) {
 269                 talloc_free(req);
 270                 return;
 271         }
 272         smb2srv_negprot_send(req, io);
 273 }
 274
 275 /*
 276  * reply to a SMB negprot request with dialect "SMB 2.002"
 277  */
 278 void smb2srv_reply_smb_negprot(struct smbsrv_request *smb_req)
 279 {
 280         struct smb2srv_request *req;
 281         uint32_t body_fixed_size = 0x26;
 282
 283         req = talloc_zero(smb_req->smb_conn, struct smb2srv_request);
 284         if (!req) goto nomem;
 285         req->smb_conn           = smb_req->smb_conn;
 286         req->request_time       = smb_req->request_time;
 287         talloc_steal(req, smb_req);
 288
 289         req->in.size      = NBT_HDR_SIZE+SMB2_HDR_BODY+body_fixed_size;
 290         req->in.allocated = req->in.size;
 291         req->in.buffer    = talloc_array(req, uint8_t, req->in.allocated);
 292         if (!req->in.buffer) goto nomem;
 293         req->in.hdr       = req->in.buffer + NBT_HDR_SIZE;
 294         req->in.body      = req->in.hdr + SMB2_HDR_BODY;
 295         req->in.body_size = body_fixed_size;
 296         req->in.dynamic   = NULL;
 297
 298         smb2srv_setup_bufinfo(req);
 299
 300         SIVAL(req->in.hdr, 0,                           SMB2_MAGIC);
 301         SSVAL(req->in.hdr, SMB2_HDR_LENGTH,             SMB2_HDR_BODY);
 302         SSVAL(req->in.hdr, SMB2_HDR_EPOCH,              0);
 303         SIVAL(req->in.hdr, SMB2_HDR_STATUS,             0);
 304         SSVAL(req->in.hdr, SMB2_HDR_OPCODE,             SMB2_OP_NEGPROT);
 305         SSVAL(req->in.hdr, SMB2_HDR_CREDIT,             0);
 306         SIVAL(req->in.hdr, SMB2_HDR_FLAGS,              0);
 307         SIVAL(req->in.hdr, SMB2_HDR_NEXT_COMMAND,       0);
 308         SBVAL(req->in.hdr, SMB2_HDR_MESSAGE_ID,         0);
 309         SIVAL(req->in.hdr, SMB2_HDR_PID,                0);
 310         SIVAL(req->in.hdr, SMB2_HDR_TID,                0);
 311         SBVAL(req->in.hdr, SMB2_HDR_SESSION_ID,         0);
 312         memset(req->in.hdr+SMB2_HDR_SIGNATURE, 0, 16);
 313
 314         /* this seems to be a bug, they use 0x24 but the length is 0x26 */
 315         SSVAL(req->in.body, 0x00, 0x24);
 316
 317         SSVAL(req->in.body, 0x02, 1);
 318         memset(req->in.body+0x04, 0, 32);
 319         SSVAL(req->in.body, 0x24, SMB2_DIALECT_REVISION_202);
 320
 321         smb2srv_negprot_recv(req);
 322         return;
 323 nomem:
 324         smbsrv_terminate_connection(smb_req->smb_conn, nt_errstr(NT_STATUS_NO_MEMORY));
 325         talloc_free(req);
 326         return;
 327 }