/*

   Unix SMB/CIFS implementation.

   SMB2 Create Context Blob handling

   Copyright (C) Andrew Tridgell 2005

   Copyright (C) Stefan Metzmacher 2008-2009

   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 "../libcli/smb/smb_common.h"

static size_t smb2_create_blob_padding(uint32_t offset, size_t n)

{

  if ((offset & (n-1)) == 0) return 0;

  return n - (offset & (n-1));

}

/*

  parse a set of SMB2 create blobs

*/

NTSTATUS smb2_create_blob_parse(TALLOC_CTX *mem_ctx, const DATA_BLOB buffer,

        struct smb2_create_blobs *blobs)

{

  const uint8_t *data = buffer.data;

  uint32_t remaining = buffer.length;

  while (remaining > 0) {

    uint32_t next;

    uint32_t name_offset, name_length;

    uint32_t data_offset;

    uint32_t data_length;

    char *tag;

    DATA_BLOB b;

    NTSTATUS status;

    if (remaining < 16) {

      return NT_STATUS_INVALID_PARAMETER;

    }

    next        = IVAL(data, 0);

    name_offset = SVAL(data, 4);

    name_length = SVAL(data, 6);

#if 0

    reserved    = SVAL(data, 8);

#endif

    data_offset = SVAL(data, 10);

    data_length = IVAL(data, 12);

    if ((next & 0x7) != 0 ||

        next > remaining ||

        name_offset != 16 ||

        name_length < 4 ||

        name_offset + name_length > remaining ||

        (data_offset & 0x7) != 0 ||

        (data_offset && (data_offset < name_offset + name_length)) ||

        (data_offset > remaining) ||

        (data_offset + (uint64_t)data_length > remaining)) {

      return NT_STATUS_INVALID_PARAMETER;

    }

    tag = talloc_strndup(mem_ctx, (const char *)data + name_offset, name_length);

    if (tag == NULL) {

      return NT_STATUS_NO_MEMORY;

    }

    b = data_blob_const(data+data_offset, data_length);

    status = smb2_create_blob_add(mem_ctx, blobs, tag, b);

    if (!NT_STATUS_IS_OK(status)) {

      return status;

    }

    talloc_free(tag);

    if (next == 0) break;

    remaining -= next;

    data += next;

    if (remaining < 16) {

      return NT_STATUS_INVALID_PARAMETER;

    }

  }

  return NT_STATUS_OK;

}

/*

  add a blob to a smb2_create attribute blob

*/

static NTSTATUS smb2_create_blob_push_one(TALLOC_CTX *mem_ctx, DATA_BLOB *buffer,

            const struct smb2_create_blob *blob,

            bool last)

{

  uint32_t ofs = buffer->length;

  size_t tag_length = strlen(blob->tag);

  size_t blob_offset = 0;

  size_t blob_pad = 0;

  size_t next_offset = 0;

  size_t next_pad = 0;

  bool ok;

  blob_offset = 0x10 + tag_length;

  blob_pad = smb2_create_blob_padding(blob_offset, 8);

  next_offset = blob_offset + blob_pad + blob->data.length;

  if (!last) {

    next_pad = smb2_create_blob_padding(next_offset, 8);

  }

  ok = data_blob_realloc(mem_ctx, buffer,

             buffer->length + next_offset + next_pad);

  if (!ok) {

    return NT_STATUS_NO_MEMORY;

  }

  if (last) {

    SIVAL(buffer->data, ofs+0x00, 0);

  } else {

    SIVAL(buffer->data, ofs+0x00, next_offset + next_pad);

  }

  SSVAL(buffer->data, ofs+0x04, 0x10); /* offset of tag */

  SIVAL(buffer->data, ofs+0x06, tag_length); /* tag length */

  SSVAL(buffer->data, ofs+0x0A, blob_offset + blob_pad); /* offset of data */

  SIVAL(buffer->data, ofs+0x0C, blob->data.length);

  memcpy(buffer->data+ofs+0x10, blob->tag, tag_length);

  if (blob_pad > 0) {

    memset(buffer->data+ofs+blob_offset, 0, blob_pad);

    blob_offset += blob_pad;

  }

  memcpy(buffer->data+ofs+blob_offset, blob->data.data, blob->data.length);

  if (next_pad > 0) {

    memset(buffer->data+ofs+next_offset, 0, next_pad);

  }

  return NT_STATUS_OK;

}

/*

  create a buffer of a set of create blobs

*/

NTSTATUS smb2_create_blob_push(TALLOC_CTX *mem_ctx, DATA_BLOB *buffer,

             const struct smb2_create_blobs blobs)

{

  uint32_t i;

  NTSTATUS status;

  *buffer = (DATA_BLOB) { 0 };

  for (i=0; i < blobs.num_blobs; i++) {

    bool last = false;

    const struct smb2_create_blob *c;

    if ((i + 1) == blobs.num_blobs) {

      last = true;

    }

    c = &blobs.blobs[i];

    status = smb2_create_blob_push_one(mem_ctx, buffer, c, last);

    if (!NT_STATUS_IS_OK(status)) {

      return status;

    }

  }

  return NT_STATUS_OK;

}

NTSTATUS smb2_create_blob_add(TALLOC_CTX *mem_ctx, struct smb2_create_blobs *b,

            const char *tag, DATA_BLOB data)

{

  struct smb2_create_blob *array;

  array = talloc_realloc(mem_ctx, b->blobs,

             struct smb2_create_blob,

             b->num_blobs + 1);

  NT_STATUS_HAVE_NO_MEMORY(array);

  b->blobs = array;

  b->blobs[b->num_blobs].tag = talloc_strdup(b->blobs, tag);

  NT_STATUS_HAVE_NO_MEMORY(b->blobs[b->num_blobs].tag);

  if (data.data) {

    b->blobs[b->num_blobs].data = data_blob_talloc(b->blobs,

                     data.data,

                     data.length);

    NT_STATUS_HAVE_NO_MEMORY(b->blobs[b->num_blobs].data.data);

  } else {

    b->blobs[b->num_blobs].data = data_blob_null;

  }

  b->num_blobs += 1;

  return NT_STATUS_OK;

}

/*

 * return the first blob with the given tag

 */

struct smb2_create_blob *smb2_create_blob_find(const struct smb2_create_blobs *b,

                 const char *tag)

{

  uint32_t i;

  if (b == NULL) {

    return NULL;

  }

  for (i=0; i < b->num_blobs; i++) {

    if (strcmp(b->blobs[i].tag, tag) == 0) {

      return &b->blobs[i];

    }

  }

  return NULL;

}