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 };
  34
  35 static void smb2cli_read_done(struct tevent_req *subreq);
  36
  37 struct tevent_req *smb2cli_read_send(TALLOC_CTX *mem_ctx,
  38                                      struct tevent_context *ev,
  39                                      struct smbXcli_conn *conn,
  40                                      uint32_t timeout_msec,
  41                                      struct smbXcli_session *session,
  42                                      struct smbXcli_tcon *tcon,
  43                                      uint32_t length,
  44                                      uint64_t offset,
  45                                      uint64_t fid_persistent,
  46                                      uint64_t fid_volatile,
  47                                      uint64_t minimum_count,
  48                                      uint64_t remaining_bytes)
  49 {
  50         struct tevent_req *req, *subreq;
  51         struct smb2cli_read_state *state;
  52         uint8_t *fixed;
  53
  54         req = tevent_req_create(mem_ctx, &state,
  55                                 struct smb2cli_read_state);
  56         if (req == NULL) {
  57                 return NULL;
  58         }
  59
  60         fixed = state->fixed;
  61
  62         SSVAL(fixed, 0, 49);
  63         SIVAL(fixed, 4, length);
  64         SBVAL(fixed, 8, offset);
  65         SBVAL(fixed, 16, fid_persistent);
  66         SBVAL(fixed, 24, fid_volatile);
  67         SBVAL(fixed, 32, minimum_count);
  68         SBVAL(fixed, 40, remaining_bytes);
  69
  70         subreq = smb2cli_req_send(state, ev, conn, SMB2_OP_READ,
  71                                   0, 0, /* flags */
  72                                   timeout_msec,
  73                                   tcon,
  74                                   session,
  75                                   state->fixed, sizeof(state->fixed),
  76                                   state->dyn_pad, sizeof(state->dyn_pad),
  77                                   length); /* max_dyn_len */
  78         if (tevent_req_nomem(subreq, req)) {
  79                 return tevent_req_post(req, ev);
  80         }
  81         tevent_req_set_callback(subreq, smb2cli_read_done, req);
  82         return req;
  83 }
  84
  85 static void smb2cli_read_done(struct tevent_req *subreq)
  86 {
  87         struct tevent_req *req = tevent_req_callback_data(
  88                 subreq, struct tevent_req);
  89         struct smb2cli_read_state *state =
  90                 tevent_req_data(req,
  91                 struct smb2cli_read_state);
  92         NTSTATUS status;
  93         NTSTATUS error;
  94         struct iovec *iov;
  95         const uint8_t dyn_ofs = SMB2_HDR_BODY + 0x10;
  96         DATA_BLOB dyn_buffer = data_blob_null;
  97         uint8_t data_offset;
  98         DATA_BLOB data_buffer = data_blob_null;
  99         uint32_t next_offset = 0; /* this variable is completely ignored */
 100         static const struct smb2cli_req_expected_response expected[] = {
 101         {
 102                 .status = STATUS_BUFFER_OVERFLOW,
 103                 .body_size = 0x11
 104         },
 105         {
 106                 .status = NT_STATUS_OK,
 107                 .body_size = 0x11
 108         }
 109         };
 110
 111         status = smb2cli_req_recv(subreq, state, &iov,
 112                                   expected, ARRAY_SIZE(expected));
 113         TALLOC_FREE(subreq);
 114         if (NT_STATUS_EQUAL(status, STATUS_BUFFER_OVERFLOW)) {
 115                 /* no error */
 116         } else {
 117                 if (tevent_req_nterror(req, status)) {
 118                         return;
 119                 }
 120         }
 121
 122         data_offset = CVAL(iov[1].iov_base, 2);
 123         state->data_length = IVAL(iov[1].iov_base, 4);
 124
 125         dyn_buffer = data_blob_const((uint8_t *)iov[2].iov_base,
 126                                      iov[2].iov_len);
 127
 128         error = smb2cli_parse_dyn_buffer(dyn_ofs,
 129                                          dyn_buffer,
 130                                          dyn_ofs, /* min_offset */
 131                                          data_offset,
 132                                          state->data_length,
 133                                          dyn_buffer.length, /* max_length */
 134                                          &next_offset,
 135                                          &data_buffer);
 136         if (tevent_req_nterror(req, error)) {
 137                 return;
 138         }
 139
 140         state->recv_iov = iov;
 141         state->data = data_buffer.data;
 142
 143         state->out_valid = true;
 144
 145         if (tevent_req_nterror(req, status)) {
 146                 return;
 147         }
 148
 149         tevent_req_done(req);
 150 }
 151
 152 NTSTATUS smb2cli_read_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 153                            uint8_t **data, uint32_t *data_length)
 154 {
 155         struct smb2cli_read_state *state =
 156                 tevent_req_data(req,
 157                 struct smb2cli_read_state);
 158         NTSTATUS status = NT_STATUS_OK;
 159
 160         if (tevent_req_is_nterror(req, &status) && !state->out_valid) {
 161                 *data_length = 0;
 162                 *data = NULL;
 163                 tevent_req_received(req);
 164                 return status;
 165         }
 166         talloc_steal(mem_ctx, state->recv_iov);
 167         *data_length = state->data_length;
 168         *data = state->data;
 169         tevent_req_received(req);
 170         return status;
 171 }
 172
 173 NTSTATUS smb2cli_read(struct smbXcli_conn *conn,
 174                       uint32_t timeout_msec,
 175                       struct smbXcli_session *session,
 176                       struct smbXcli_tcon *tcon,
 177                       uint32_t length,
 178                       uint64_t offset,
 179                       uint64_t fid_persistent,
 180                       uint64_t fid_volatile,
 181                       uint64_t minimum_count,
 182                       uint64_t remaining_bytes,
 183                       TALLOC_CTX *mem_ctx,
 184                       uint8_t **data,
 185                       uint32_t *data_length)
 186 {
 187         TALLOC_CTX *frame = talloc_stackframe();
 188         struct tevent_context *ev;
 189         struct tevent_req *req;
 190         NTSTATUS status = NT_STATUS_NO_MEMORY;
 191
 192         if (smbXcli_conn_has_async_calls(conn)) {
 193                 /*
 194                  * Can't use sync call while an async call is in flight
 195                  */
 196                 status = NT_STATUS_INVALID_PARAMETER;
 197                 goto fail;
 198         }
 199         ev = samba_tevent_context_init(frame);
 200         if (ev == NULL) {
 201                 goto fail;
 202         }
 203         req = smb2cli_read_send(frame, ev,
 204                                 conn, timeout_msec, session, tcon,
 205                                 length, offset,
 206                                 fid_persistent, fid_volatile,
 207                                 minimum_count, remaining_bytes);
 208         if (req == NULL) {
 209                 goto fail;
 210         }
 211         if (!tevent_req_poll_ntstatus(req, ev, &status)) {
 212                 goto fail;
 213         }
 214         status = smb2cli_read_recv(req, mem_ctx, data, data_length);
 215  fail:
 216         TALLOC_FREE(frame);
 217         return status;
 218 }