libcli/smb/smb2cli_read.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    smb2 lib
   4    Copyright (C) Volker Lendecke 2011
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "includes.h"
  21 #include "system/network.h"
  22 #include "lib/util/tevent_ntstatus.h"
  23 #include "smb_common.h"
  24 #include "smbXcli_base.h"
  25
  26 struct smb2cli_read_state {
  27         uint8_t fixed[48];
  28         uint8_t dyn_pad[1];
  29         struct iovec *recv_iov;
  30         uint8_t *data;
  31         uint32_t data_length;
  32         bool out_valid;
  33         struct tevent_req *subreq;
  34         bool notify_async;
  35         bool report_pending;
  36 };
  37
  38 static bool smb2cli_read_cancel(struct tevent_req *req);
  39 static void smb2cli_read_done(struct tevent_req *subreq);
  40
  41 struct tevent_req *smb2cli_read_send(TALLOC_CTX *mem_ctx,
  42                                      struct tevent_context *ev,
  43                                      struct smbXcli_conn *conn,
  44                                      uint32_t timeout_msec,
  45                                      struct smbXcli_session *session,
  46                                      struct smbXcli_tcon *tcon,
  47                                      uint32_t length,
  48                                      uint64_t offset,
  49                                      uint64_t fid_persistent,
  50                                      uint64_t fid_volatile,
  51                                      uint64_t minimum_count,
  52                                      uint64_t remaining_bytes)
  53 {
  54         struct tevent_req *req, *subreq;
  55         struct smb2cli_read_state *state;
  56         uint8_t *fixed;
  57
  58         req = tevent_req_create(mem_ctx, &state,
  59                                 struct smb2cli_read_state);
  60         if (req == NULL) {
  61                 return NULL;
  62         }
  63
  64         fixed = state->fixed;
  65
  66         SSVAL(fixed, 0, 49);
  67         SIVAL(fixed, 4, length);
  68         SBVAL(fixed, 8, offset);
  69         SBVAL(fixed, 16, fid_persistent);
  70         SBVAL(fixed, 24, fid_volatile);
  71         SBVAL(fixed, 32, minimum_count);
  72         SBVAL(fixed, 40, remaining_bytes);
  73
  74         subreq = smb2cli_req_send(state, ev, conn, SMB2_OP_READ,
  75                                   0, 0, /* flags */
  76                                   timeout_msec,
  77                                   tcon,
  78                                   session,
  79                                   state->fixed, sizeof(state->fixed),
  80                                   state->dyn_pad, sizeof(state->dyn_pad),
  81                                   length); /* max_dyn_len */
  82         if (tevent_req_nomem(subreq, req)) {
  83                 return tevent_req_post(req, ev);
  84         }
  85         tevent_req_set_callback(subreq, smb2cli_read_done, req);
  86         state->subreq = subreq;
  87         tevent_req_set_cancel_fn(req, smb2cli_read_cancel);
  88
  89         return req;
  90 }
  91
  92 static bool smb2cli_read_cancel(struct tevent_req *req)
  93 {
  94         struct smb2cli_read_state *state = tevent_req_data(
  95                 req, struct smb2cli_read_state);
  96         bool ok;
  97
  98         ok = tevent_req_cancel(state->subreq);
  99         return ok;
 100 }
 101
 102 void smb2cli_read_set_notify_async(struct tevent_req *req)
 103 {
 104         struct smb2cli_read_state *state =
 105                 tevent_req_data(req,
 106                 struct smb2cli_read_state);
 107
 108         smb2cli_req_set_notify_async(state->subreq);
 109         state->notify_async = true;
 110 }
 111
 112 static void smb2cli_read_done(struct tevent_req *subreq)
 113 {
 114         struct tevent_req *req = tevent_req_callback_data(
 115                 subreq, struct tevent_req);
 116         struct smb2cli_read_state *state =
 117                 tevent_req_data(req,
 118                 struct smb2cli_read_state);
 119         NTSTATUS status;
 120         NTSTATUS error;
 121         struct iovec *iov;
 122         const uint8_t dyn_ofs = SMB2_HDR_BODY + 0x10;
 123         DATA_BLOB dyn_buffer = data_blob_null;
 124         uint8_t data_offset;
 125         DATA_BLOB data_buffer = data_blob_null;
 126         uint32_t next_offset = 0; /* this variable is completely ignored */
 127         static const struct smb2cli_req_expected_response expected[] = {
 128         {
 129                 .status = STATUS_BUFFER_OVERFLOW,
 130                 .body_size = 0x11
 131         },
 132         {
 133                 .status = NT_STATUS_OK,
 134                 .body_size = 0x11
 135         }
 136         };
 137
 138         SMB_ASSERT(state->subreq == subreq);
 139
 140         status = smb2cli_req_recv(subreq, state, &iov,
 141                                   expected, ARRAY_SIZE(expected));
 142         if (NT_STATUS_EQUAL(status, NT_STATUS_PENDING) && state->notify_async) {
 143                 state->notify_async = false;
 144                 state->report_pending = true;
 145                 tevent_req_notify_callback(req);
 146                 return;
 147         }
 148         state->notify_async = false;
 149         state->report_pending = false;
 150         state->subreq = NULL;
 151         TALLOC_FREE(subreq);
 152         if (NT_STATUS_EQUAL(status, STATUS_BUFFER_OVERFLOW)) {
 153                 /* no error */
 154         } else {
 155                 if (tevent_req_nterror(req, status)) {
 156                         return;
 157                 }
 158         }
 159
 160         data_offset = CVAL(iov[1].iov_base, 2);
 161         state->data_length = IVAL(iov[1].iov_base, 4);
 162
 163         dyn_buffer = data_blob_const((uint8_t *)iov[2].iov_base,
 164                                      iov[2].iov_len);
 165
 166         error = smb2cli_parse_dyn_buffer(dyn_ofs,
 167                                          dyn_buffer,
 168                                          dyn_ofs, /* min_offset */
 169                                          data_offset,
 170                                          state->data_length,
 171                                          dyn_buffer.length, /* max_length */
 172                                          &next_offset,
 173                                          &data_buffer);
 174         if (tevent_req_nterror(req, error)) {
 175                 return;
 176         }
 177
 178         state->recv_iov = iov;
 179         state->data = data_buffer.data;
 180
 181         state->out_valid = true;
 182
 183         if (tevent_req_nterror(req, status)) {
 184                 return;
 185         }
 186
 187         tevent_req_done(req);
 188 }
 189
 190 NTSTATUS smb2cli_read_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 191                            uint8_t **data, uint32_t *data_length)
 192 {
 193         struct smb2cli_read_state *state =
 194                 tevent_req_data(req,
 195                 struct smb2cli_read_state);
 196         NTSTATUS status = NT_STATUS_OK;
 197
 198         if (state->report_pending) {
 199                 *data_length = 0;
 200                 *data = NULL;
 201                 return NT_STATUS_PENDING;
 202         }
 203
 204         if (tevent_req_is_nterror(req, &status) && !state->out_valid) {
 205                 *data_length = 0;
 206                 *data = NULL;
 207                 tevent_req_received(req);
 208                 return status;
 209         }
 210         talloc_steal(mem_ctx, state->recv_iov);
 211         *data_length = state->data_length;
 212         *data = state->data;
 213         tevent_req_received(req);
 214         return status;
 215 }
 216
 217 NTSTATUS smb2cli_read(struct smbXcli_conn *conn,
 218                       uint32_t timeout_msec,
 219                       struct smbXcli_session *session,
 220                       struct smbXcli_tcon *tcon,
 221                       uint32_t length,
 222                       uint64_t offset,
 223                       uint64_t fid_persistent,
 224                       uint64_t fid_volatile,
 225                       uint64_t minimum_count,
 226                       uint64_t remaining_bytes,
 227                       TALLOC_CTX *mem_ctx,
 228                       uint8_t **data,
 229                       uint32_t *data_length)
 230 {
 231         TALLOC_CTX *frame = talloc_stackframe();
 232         struct tevent_context *ev;
 233         struct tevent_req *req;
 234         NTSTATUS status = NT_STATUS_NO_MEMORY;
 235
 236         if (smbXcli_conn_has_async_calls(conn)) {
 237                 /*
 238                  * Can't use sync call while an async call is in flight
 239                  */
 240                 status = NT_STATUS_INVALID_PARAMETER;
 241                 goto fail;
 242         }
 243         ev = samba_tevent_context_init(frame);
 244         if (ev == NULL) {
 245                 goto fail;
 246         }
 247         req = smb2cli_read_send(frame, ev,
 248                                 conn, timeout_msec, session, tcon,
 249                                 length, offset,
 250                                 fid_persistent, fid_volatile,
 251                                 minimum_count, remaining_bytes);
 252         if (req == NULL) {
 253                 goto fail;
 254         }
 255         if (!tevent_req_poll_ntstatus(req, ev, &status)) {
 256                 goto fail;
 257         }
 258         status = smb2cli_read_recv(req, mem_ctx, data, data_length);
 259  fail:
 260         TALLOC_FREE(frame);
 261         return status;
 262 }