/*

   Unix SMB/CIFS implementation.

   Core SMB2 server

   Copyright (C) Stefan Metzmacher 2009

   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 3 of the License, or

   (at your option) any later version.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   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, see <http://www.gnu.org/licenses/>.

*/

#include "includes.h"

#include "system/filesys.h"

#include "smbd/smbd.h"

#include "smbd/globals.h"

#include "../libcli/smb/smb_common.h"

#include "libcli/security/security.h"

#include "../lib/util/tevent_ntstatus.h"

#include "rpc_server/srv_pipe_hnd.h"

#include "lib/util/sys_rw_data.h"

#undef DBGC_CLASS

#define DBGC_CLASS DBGC_SMB2

static struct tevent_req *smbd_smb2_read_send(TALLOC_CTX *mem_ctx,

                struct tevent_context *ev,

                struct smbd_smb2_request *smb2req,

                struct files_struct *in_fsp,

                uint8_t in_flags,

                uint32_t in_length,

                uint64_t in_offset,

                uint32_t in_minimum,

                uint32_t in_remaining);

static NTSTATUS smbd_smb2_read_recv(struct tevent_req *req,

            TALLOC_CTX *mem_ctx,

            DATA_BLOB *out_data,

            uint32_t *out_remaining);

static void smbd_smb2_request_read_done(struct tevent_req *subreq);

NTSTATUS smbd_smb2_request_process_read(struct smbd_smb2_request *req)

{

  struct smbXsrv_connection *xconn = req->xconn;

  NTSTATUS status;

  const uint8_t *inbody;

  uint8_t in_flags;

  uint32_t in_length;

  uint64_t in_offset;

  uint64_t in_file_id_persistent;

  uint64_t in_file_id_volatile;

  struct files_struct *in_fsp;

  uint32_t in_minimum_count;

  uint32_t in_remaining_bytes;

  struct tevent_req *subreq;

  status = smbd_smb2_request_verify_sizes(req, 0x31);

  if (!NT_STATUS_IS_OK(status)) {

    return smbd_smb2_request_error(req, status);

  }

  inbody = SMBD_SMB2_IN_BODY_PTR(req);

  if (xconn->protocol >= PROTOCOL_SMB3_02) {

    in_flags    = CVAL(inbody, 0x03);

  } else {

    in_flags    = 0;

  }

  in_length   = IVAL(inbody, 0x04);

  in_offset   = BVAL(inbody, 0x08);

  in_file_id_persistent = BVAL(inbody, 0x10);

  in_file_id_volatile = BVAL(inbody, 0x18);

  in_minimum_count  = IVAL(inbody, 0x20);

  in_remaining_bytes  = IVAL(inbody, 0x28);

  /* check the max read size */

  if (in_length > xconn->smb2.server.max_read) {

    DEBUG(2,("smbd_smb2_request_process_read: "

       "client ignored max read: %s: 0x%08X: 0x%08X\n",

      __location__, in_length, xconn->smb2.server.max_read));

    return smbd_smb2_request_error(req, NT_STATUS_INVALID_PARAMETER);

  }

  status = smbd_smb2_request_verify_creditcharge(req, in_length);

  if (!NT_STATUS_IS_OK(status)) {

    return smbd_smb2_request_error(req, status);

  }

  in_fsp = file_fsp_smb2(req, in_file_id_persistent, in_file_id_volatile);

  if (in_fsp == NULL) {

    return smbd_smb2_request_error(req, NT_STATUS_FILE_CLOSED);

  }

  subreq = smbd_smb2_read_send(req, req->sconn->ev_ctx,

             req, in_fsp,

             in_flags,

             in_length,

             in_offset,

             in_minimum_count,

             in_remaining_bytes);

  if (subreq == NULL) {

    return smbd_smb2_request_error(req, NT_STATUS_NO_MEMORY);

  }

  tevent_req_set_callback(subreq, smbd_smb2_request_read_done, req);

  return smbd_smb2_request_pending_queue(req, subreq, 500);

}

static void smbd_smb2_request_read_done(struct tevent_req *subreq)

{

  struct smbd_smb2_request *req = tevent_req_callback_data(subreq,

          struct smbd_smb2_request);

  uint16_t body_size;

  uint8_t body_padding = req->xconn->smb2.smbtorture.read_body_padding;

  DATA_BLOB outbody;

  DATA_BLOB outdyn;

  uint8_t out_data_offset;

  DATA_BLOB out_data_buffer = data_blob_null;

  uint32_t out_data_remaining = 0;

  NTSTATUS status;

  NTSTATUS error; /* transport error */

  status = smbd_smb2_read_recv(subreq,

             req,

             &out_data_buffer,

             &out_data_remaining);

  TALLOC_FREE(subreq);

  if (!NT_STATUS_IS_OK(status)) {

    error = smbd_smb2_request_error(req, status);

    if (!NT_STATUS_IS_OK(error)) {

      smbd_server_connection_terminate(req->xconn,

               nt_errstr(error));

      return;

    }

    return;

  }

  /*

   * Only FSCTL_SMBTORTURE_GLOBAL_READ_RESPONSE_BODY_PADDING8

   * sets body_padding to a value different from 0.

   */

  body_size = 0x10 + body_padding;

  out_data_offset = SMB2_HDR_BODY + body_size;

  outbody = smbd_smb2_generate_outbody(req, body_size);

  if (outbody.data == NULL) {

    error = smbd_smb2_request_error(req, NT_STATUS_NO_MEMORY);

    if (!NT_STATUS_IS_OK(error)) {

      smbd_server_connection_terminate(req->xconn,

               nt_errstr(error));

      return;

    }

    return;

  }

  SSVAL(outbody.data, 0x00, 0x10 + 1); /* struct size */

  SCVAL(outbody.data, 0x02,

        out_data_offset);     /* data offset */

  SCVAL(outbody.data, 0x03, 0);    /* reserved */

  SIVAL(outbody.data, 0x04,

        out_data_buffer.length);    /* data length */

  SIVAL(outbody.data, 0x08,

        out_data_remaining);    /* data remaining */

  SIVAL(outbody.data, 0x0C, 0);    /* reserved */

  if (body_padding != 0) {

    memset(outbody.data + 0x10, 0, body_padding);

  }

  outdyn = out_data_buffer;

  error = smbd_smb2_request_done(req, outbody, &outdyn);

  if (!NT_STATUS_IS_OK(error)) {

    smbd_server_connection_terminate(req->xconn,

             nt_errstr(error));

    return;

  }

}

struct smbd_smb2_read_state {

  struct smbd_smb2_request *smb2req;

  struct smb_request *smbreq;

  struct tevent_req *ipc_subreq;

  files_struct *fsp;

  uint8_t in_flags;

  uint32_t in_length;

  uint64_t in_offset;

  uint32_t in_minimum;

  DATA_BLOB out_headers;

  uint8_t _out_hdr_buf[NBT_HDR_SIZE + SMB2_HDR_BODY + 0x10];

  DATA_BLOB out_data;

  uint32_t out_remaining;

};

static int smb2_smb2_read_state_deny_destructor(struct smbd_smb2_read_state *state)

{

  return -1;

}

/* struct smbd_smb2_read_state destructor. Send the SMB2_READ data. */

static int smb2_sendfile_send_data(struct smbd_smb2_read_state *state)

{

  uint32_t in_length = state->in_length;

  uint64_t in_offset = state->in_offset;

  files_struct *fsp = state->fsp;

  const DATA_BLOB *hdr = state->smb2req->queue_entry.sendfile_header;

  NTSTATUS *pstatus = state->smb2req->queue_entry.sendfile_status;

  struct smbXsrv_connection *xconn = state->smb2req->xconn;

  ssize_t nread;

  ssize_t ret;

  int saved_errno;

  nread = SMB_VFS_SENDFILE(xconn->transport.sock,

         fsp,

         hdr,

         in_offset,

         in_length);

  DBG_DEBUG("SMB_VFS_SENDFILE returned %zd on file %s\n",

      nread,

      fsp_str_dbg(fsp));

  if (nread == -1) {

    saved_errno = errno;

    /*

     * Returning ENOSYS means no data at all was sent.

       Do this as a normal read. */

    if (errno == ENOSYS) {

      goto normal_read;

    }

    if (errno == ENOTSUP) {

      set_use_sendfile(SNUM(fsp->conn), false);

      DBG_WARNING("Disabling sendfile use as sendfile is "

            "not supported by the system\n");

      goto normal_read;

    }

    if (errno == EINTR) {

      /*

       * Special hack for broken Linux with no working sendfile. If we

       * return EINTR we sent the header but not the rest of the data.

       * Fake this up by doing read/write calls.

       */

      set_use_sendfile(SNUM(fsp->conn), false);

      nread = fake_sendfile(xconn, fsp, in_offset, in_length);

      if (nread == -1) {

        saved_errno = errno;

        DBG_ERR("fake_sendfile failed for file %s "

          "(%s) for client %s. Terminating\n",

          fsp_str_dbg(fsp),

          strerror(saved_errno),

          smbXsrv_connection_dbg(xconn));

        *pstatus = map_nt_error_from_unix_common(saved_errno);

        return 0;

      }

      goto out;

    }

    DBG_ERR("sendfile failed for file "

      "%s (%s) for client %s. Terminating\n",

      fsp_str_dbg(fsp),

      strerror(saved_errno),

      smbXsrv_connection_dbg(xconn));

    *pstatus = map_nt_error_from_unix_common(saved_errno);

    return 0;

  } else if (nread == 0) {

    /*

     * Some sendfile implementations return 0 to indicate

     * that there was a short read, but nothing was

     * actually written to the socket.  In this case,

     * fallback to the normal read path so the header gets

     * the correct byte count.

     */

    DBG_NOTICE("sendfile sent zero bytes "

         "falling back to the normal read: %s\n",

         fsp_str_dbg(fsp));

    goto normal_read;

  }

  /*

   * We got a short read

   */

  goto out;

normal_read:

  /* Send out the header. */

  ret = write_data(xconn->transport.sock,

       (const char *)hdr->data, hdr->length);

  if (ret != hdr->length) {

    saved_errno = errno;

    DBG_ERR("write_data failed for file "

      "%s (%s) for client %s. Terminating\n",

      fsp_str_dbg(fsp),

      strerror(saved_errno),

      smbXsrv_connection_dbg(xconn));

    *pstatus = map_nt_error_from_unix_common(saved_errno);

    return 0;

  }

  nread = fake_sendfile(xconn, fsp, in_offset, in_length);

  if (nread == -1) {

    saved_errno = errno;

    DBG_ERR("fake_sendfile failed for file %s (%s) for client %s. "

      "Terminating\n",

      fsp_str_dbg(fsp),

      strerror(saved_errno),

      smbXsrv_connection_dbg(xconn));

    *pstatus = map_nt_error_from_unix_common(saved_errno);

    return 0;

  }

  out:

  if (nread < in_length) {

    ret = sendfile_short_send(xconn, fsp, nread,

            hdr->length, in_length);

    if (ret == -1) {

      saved_errno = errno;

      DBG_ERR("sendfile_short_send "

        "failed for file %s (%s) for client %s. "

        "Terminating\n",

        fsp_str_dbg(fsp),

        strerror(saved_errno),

        smbXsrv_connection_dbg(xconn));

      *pstatus = map_nt_error_from_unix_common(saved_errno);

      return 0;

    }

  }

  *pstatus = NT_STATUS_OK;

  return 0;

}

static NTSTATUS schedule_smb2_sendfile_read(struct smbd_smb2_request *smb2req,

          struct smbd_smb2_read_state *state)

{

  files_struct *fsp = state->fsp;

  /*

   * We cannot use sendfile if...

   * We were not configured to do so OR

   * Signing is active OR

   * This is a compound SMB2 operation OR

   * fsp is a STREAM file OR

   * It's not a regular file OR

   * Requested offset is greater than file size OR

   * there's not enough data in the file.

   * Phew :-). Luckily this means most

   * reads on most normal files. JRA.

  */

  if (!lp__use_sendfile(SNUM(fsp->conn)) ||

      smb2req->do_signing ||

      smb2req->do_encryption ||

      smbd_smb2_is_compound(smb2req) ||

      fsp_is_alternate_stream(fsp) ||

      (!S_ISREG(fsp->fsp_name->st.st_ex_mode)) ||

      (state->in_offset >= fsp->fsp_name->st.st_ex_size) ||

      (fsp->fsp_name->st.st_ex_size < state->in_offset + state->in_length))

  {

    return NT_STATUS_RETRY;

  }

  /* We've already checked there's this amount of data

     to read. */

  state->out_data.length = state->in_length;

  state->out_remaining = 0;

  state->out_headers = data_blob_const(state->_out_hdr_buf,

               sizeof(state->_out_hdr_buf));

  return NT_STATUS_OK;

}

static void smbd_smb2_read_pipe_done(struct tevent_req *subreq);

/*******************************************************************

 Common read complete processing function for both synchronous and

 asynchronous reads.

*******************************************************************/

NTSTATUS smb2_read_complete(struct tevent_req *req, ssize_t nread, int err)

{

  struct smbd_smb2_read_state *state = tevent_req_data(req,

          struct smbd_smb2_read_state);

  files_struct *fsp = state->fsp;

  if (nread < 0) {

    NTSTATUS status = map_nt_error_from_unix(err);

    DEBUG( 3,( "smb2_read_complete: file %s nread = %d. "

      "Error = %s (NTSTATUS %s)\n",

      fsp_str_dbg(fsp),

      (int)nread,

      strerror(err),

      nt_errstr(status)));

    return status;

  }

  if (nread == 0 && state->in_length != 0) {

    DEBUG(5,("smb2_read_complete: read_file[%s] end of file\n",

      fsp_str_dbg(fsp)));

    return NT_STATUS_END_OF_FILE;

  }

  if (nread < state->in_minimum) {

    DEBUG(5,("smb2_read_complete: read_file[%s] read less %d than "

      "minimum requested %u. Returning end of file\n",

      fsp_str_dbg(fsp),

      (int)nread,

      (unsigned int)state->in_minimum));

    return NT_STATUS_END_OF_FILE;

  }

  DEBUG(3,("smbd_smb2_read: %s, file %s, length=%lu offset=%lu read=%lu\n",

    fsp_fnum_dbg(fsp),

    fsp_str_dbg(fsp),

    (unsigned long)state->in_length,

    (unsigned long)state->in_offset,

    (unsigned long)nread));

  state->out_data.length = nread;

  state->out_remaining = 0;

  return NT_STATUS_OK;

}

static bool smbd_smb2_read_ipc_cancel(struct tevent_req *req)

{

  struct smbd_smb2_read_state *state =

    tevent_req_data(req,

    struct smbd_smb2_read_state);

  TALLOC_FREE(state->ipc_subreq);

  tevent_req_defer_callback(req, state->smb2req->xconn->client->raw_ev_ctx);

  if (state->fsp->fsp_flags.closing) {

    tevent_req_nterror(req, NT_STATUS_PIPE_BROKEN);

  } else {

    tevent_req_nterror(req, NT_STATUS_CANCELLED);

  }

  return true;

}

static bool smbd_smb2_read_cancel(struct tevent_req *req)

{

  struct smbd_smb2_read_state *state =

    tevent_req_data(req,

    struct smbd_smb2_read_state);

  return cancel_smb2_aio(state->smbreq);

}

static struct tevent_req *smbd_smb2_read_send(TALLOC_CTX *mem_ctx,

                struct tevent_context *ev,

                struct smbd_smb2_request *smb2req,

                struct files_struct *fsp,

                uint8_t in_flags,

                uint32_t in_length,

                uint64_t in_offset,

                uint32_t in_minimum,

                uint32_t in_remaining)

{

  NTSTATUS status;

  struct tevent_req *req = NULL;

  struct smbd_smb2_read_state *state = NULL;

  struct smb_request *smbreq = NULL;

  connection_struct *conn = smb2req->tcon->compat;

  ssize_t nread = -1;

  struct lock_struct lock;

  int saved_errno;

  req = tevent_req_create(mem_ctx, &state,

        struct smbd_smb2_read_state);

  if (req == NULL) {

    return NULL;

  }

  state->smb2req = smb2req;

  state->in_flags = in_flags;

  state->in_length = in_length;

  state->in_offset = in_offset;

  state->in_minimum = in_minimum;

  state->out_data = data_blob_null;

  state->out_remaining = 0;

  DEBUG(10,("smbd_smb2_read: %s - %s\n",

      fsp_str_dbg(fsp), fsp_fnum_dbg(fsp)));

  smbreq = smbd_smb2_fake_smb_request(smb2req, fsp);

  if (tevent_req_nomem(smbreq, req)) {

    return tevent_req_post(req, ev);

  }

  state->smbreq = smbreq;

  if (fsp->fsp_flags.is_directory) {

    tevent_req_nterror(req, NT_STATUS_INVALID_DEVICE_REQUEST);

    return tevent_req_post(req, ev);

  }

  state->fsp = fsp;

  if (IS_IPC(smbreq->conn)) {

    struct tevent_req *subreq = NULL;

    struct aio_req_fsp_link *aio_lnk = NULL;

    state->out_data = data_blob_talloc(state, NULL, in_length);

    if (in_length > 0 && tevent_req_nomem(state->out_data.data, req)) {

      return tevent_req_post(req, ev);

    }

    if (!fsp_is_np(fsp)) {

      tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);

      return tevent_req_post(req, ev);

    }

    subreq = np_read_send(state, ev,

              fsp->fake_file_handle,

              state->out_data.data,

              state->out_data.length);

    if (tevent_req_nomem(subreq, req)) {

      return tevent_req_post(req, ev);

    }

    tevent_req_set_callback(subreq,

          smbd_smb2_read_pipe_done,

          req);

    /*

     * Make sure we mark the fsp as having outstanding async

     * activity so we don't crash on shutdown close.

     */

    aio_lnk = aio_add_req_to_fsp(fsp, req);

    if (aio_lnk == NULL) {

      tevent_req_nterror(req, NT_STATUS_NO_MEMORY);

      return tevent_req_post(req, ev);

    }

    talloc_move(subreq, &aio_lnk);

    state->ipc_subreq = subreq;

    tevent_req_set_cancel_fn(req, smbd_smb2_read_ipc_cancel);

    return req;

  }

  if (!CHECK_READ_SMB2(fsp)) {

    tevent_req_nterror(req, NT_STATUS_ACCESS_DENIED);

    return tevent_req_post(req, ev);

  }

  status = schedule_smb2_aio_read(fsp->conn,

        smbreq,

        fsp,

        state,

        &state->out_data,

        (off_t)in_offset,

        (size_t)in_length);

  if (NT_STATUS_IS_OK(status)) {

    /*

     * Doing an async read, allow this

     * request to be canceled

     */

    tevent_req_set_cancel_fn(req, smbd_smb2_read_cancel);

    return req;

  }

  if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {

    /* Real error in setting up aio. Fail. */

    tevent_req_nterror(req, status);

    return tevent_req_post(req, ev);

  }

  /* Fallback to synchronous. */

  init_strict_lock_struct(fsp,

        fsp->op->global->open_persistent_id,

        in_offset,

        in_length,

        READ_LOCK,

        &lock);

  if (!SMB_VFS_STRICT_LOCK_CHECK(conn, fsp, &lock)) {

    tevent_req_nterror(req, NT_STATUS_FILE_LOCK_CONFLICT);

    return tevent_req_post(req, ev);

  }

  /* Try sendfile in preference. */

  status = schedule_smb2_sendfile_read(smb2req, state);

  if (NT_STATUS_IS_OK(status)) {

    tevent_req_done(req);

    return tevent_req_post(req, ev);

  }

  if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {

    tevent_req_nterror(req, status);

    return tevent_req_post(req, ev);

  }

  /* Ok, read into memory. Allocate the out buffer. */

  state->out_data = data_blob_talloc(state, NULL, in_length);

  if (in_length > 0 && tevent_req_nomem(state->out_data.data, req)) {

    return tevent_req_post(req, ev);

  }

  nread = read_file(fsp,

        (char *)state->out_data.data,

        in_offset,

        in_length);

  saved_errno = errno;

  DEBUG(10,("smbd_smb2_read: file %s, %s, offset=%llu "

    "len=%llu returned %lld\n",

    fsp_str_dbg(fsp),

    fsp_fnum_dbg(fsp),

    (unsigned long long)in_offset,

    (unsigned long long)in_length,

    (long long)nread));

  status = smb2_read_complete(req, nread, saved_errno);

  if (!NT_STATUS_IS_OK(status)) {

    tevent_req_nterror(req, status);

  } else {

    /* Success. */

    tevent_req_done(req);

  }

  return tevent_req_post(req, ev);

}

static void smbd_smb2_read_pipe_done(struct tevent_req *subreq)

{

  struct tevent_req *req = tevent_req_callback_data(subreq,

         struct tevent_req);

  struct smbd_smb2_read_state *state = tevent_req_data(req,

               struct smbd_smb2_read_state);

  NTSTATUS status;

  ssize_t nread = -1;

  bool is_data_outstanding;

  status = np_read_recv(subreq, &nread, &is_data_outstanding);

  TALLOC_FREE(subreq);

  if (!NT_STATUS_IS_OK(status)) {

    NTSTATUS old = status;

    status = nt_status_np_pipe(old);

    tevent_req_nterror(req, status);

    return;

  }

  if (nread == 0 && state->out_data.length != 0) {

    tevent_req_nterror(req, NT_STATUS_END_OF_FILE);

    return;

  }

  state->out_data.length = nread;

  state->out_remaining = 0;

  /*

   * TODO: add STATUS_BUFFER_OVERFLOW handling, once we also

   * handle it in SMB1 pipe_read_andx_done().

   */

  tevent_req_done(req);

}

static NTSTATUS smbd_smb2_read_recv(struct tevent_req *req,

            TALLOC_CTX *mem_ctx,

            DATA_BLOB *out_data,

            uint32_t *out_remaining)

{

  NTSTATUS status;

  struct smbd_smb2_read_state *state = tevent_req_data(req,

               struct smbd_smb2_read_state);

  if (tevent_req_is_nterror(req, &status)) {

    tevent_req_received(req);

    return status;

  }

  *out_data = state->out_data;

  talloc_steal(mem_ctx, out_data->data);

  *out_remaining = state->out_remaining;

  if (state->out_headers.length > 0) {

    talloc_steal(mem_ctx, state);

    talloc_set_destructor(state, smb2_smb2_read_state_deny_destructor);

    tevent_req_received(req);

    state->smb2req->queue_entry.sendfile_header = &state->out_headers;

    state->smb2req->queue_entry.sendfile_body_size = state->in_length;

    talloc_set_destructor(state, smb2_sendfile_send_data);

  } else {

    tevent_req_received(req);

  }

  return NT_STATUS_OK;

}