source3/smbd/smb1_utils.c

   1 /*
   2  * Unix SMB/CIFS implementation.
   3  * Util functions valid in the SMB1 server
   4  *
   5  * Copyright (C) Volker Lendecke 2019
   6  * Copyright by the authors of the functions moved here eventually
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 3 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20  */
  21
  22 #include "includes.h"
  23 #include "smbd/smbd.h"
  24 #include "smbd/globals.h"
  25 #include "libcli/security/security.h"
  26 #include "lib/util/sys_rw_data.h"
  27 #include "smbd/fd_handle.h"
  28
  29 /****************************************************************************
  30  Special FCB or DOS processing in the case of a sharing violation.
  31  Try and find a duplicated file handle.
  32 ****************************************************************************/
  33
  34 struct files_struct *fcb_or_dos_open(
  35         struct smb_request *req,
  36         const struct smb_filename *smb_fname,
  37         uint32_t access_mask,
  38         uint32_t create_options,
  39         uint32_t private_flags)
  40 {
  41         struct connection_struct *conn = req->conn;
  42         struct file_id id = vfs_file_id_from_sbuf(conn, &smb_fname->st);
  43         struct files_struct *fsp = NULL, *new_fsp = NULL;
  44         NTSTATUS status;
  45
  46         if ((private_flags &
  47              (NTCREATEX_FLAG_DENY_DOS|
  48               NTCREATEX_FLAG_DENY_FCB))
  49             == 0) {
  50                 return NULL;
  51         }
  52
  53         for(fsp = file_find_di_first(conn->sconn, id, true);
  54             fsp != NULL;
  55             fsp = file_find_di_next(fsp, true)) {
  56
  57                 DBG_DEBUG("Checking file %s, fd = %d, vuid = %"PRIu64", "
  58                           "file_pid = %"PRIu16", "
  59                           "private_options = 0x%"PRIx32", "
  60                           "access_mask = 0x%"PRIx32"\n",
  61                           fsp_str_dbg(fsp),
  62                           fsp_get_pathref_fd(fsp),
  63                           fsp->vuid,
  64                           fsp->file_pid,
  65                           fh_get_private_options(fsp->fh),
  66                           fsp->access_mask);
  67
  68                 if (fsp_get_pathref_fd(fsp) != -1 &&
  69                     fsp->vuid == req->vuid &&
  70                     fsp->file_pid == req->smbpid &&
  71                     (fh_get_private_options(fsp->fh) &
  72                      (NTCREATEX_FLAG_DENY_DOS |
  73                       NTCREATEX_FLAG_DENY_FCB)) &&
  74                     (fsp->access_mask & FILE_WRITE_DATA) &&
  75                     strequal(fsp->fsp_name->base_name, smb_fname->base_name) &&
  76                     strequal(fsp->fsp_name->stream_name,
  77                              smb_fname->stream_name)) {
  78                         DBG_DEBUG("file match\n");
  79                         break;
  80                 }
  81         }
  82
  83         if (fsp == NULL) {
  84                 return NULL;
  85         }
  86
  87         /* quite an insane set of semantics ... */
  88         if (is_executable(smb_fname->base_name) &&
  89             (fh_get_private_options(fsp->fh) & NTCREATEX_FLAG_DENY_DOS)) {
  90                 DBG_DEBUG("file fail due to is_executable.\n");
  91                 return NULL;
  92         }
  93
  94         status = file_new(req, conn, &new_fsp);
  95         if (!NT_STATUS_IS_OK(status)) {
  96                 DBG_DEBUG("file_new failed: %s\n", nt_errstr(status));
  97                 return NULL;
  98         }
  99
 100         status = dup_file_fsp(fsp, access_mask, new_fsp);
 101
 102         if (!NT_STATUS_IS_OK(status)) {
 103                 DBG_DEBUG("dup_file_fsp failed: %s\n", nt_errstr(status));
 104                 file_free(req, new_fsp);
 105                 return NULL;
 106         }
 107
 108         return new_fsp;
 109 }
 110
 111 /****************************************************************************
 112  Send a keepalive packet (rfc1002).
 113 ****************************************************************************/
 114
 115 bool send_keepalive(int client)
 116 {
 117         unsigned char buf[4];
 118
 119         buf[0] = NBSSkeepalive;
 120         buf[1] = buf[2] = buf[3] = 0;
 121
 122         return(write_data(client,(char *)buf,4) == 4);
 123 }
 124
 125 /*******************************************************************
 126  Add a string to the end of a smb_buf, adjusting bcc and smb_len.
 127  Return the bytes added
 128 ********************************************************************/
 129
 130 ssize_t message_push_string(uint8_t **outbuf, const char *str, int flags)
 131 {
 132         size_t buf_size = smb_len(*outbuf) + 4;
 133         size_t grow_size;
 134         size_t result = 0;
 135         uint8_t *tmp;
 136         NTSTATUS status;
 137
 138         /*
 139          * We need to over-allocate, now knowing what srvstr_push will
 140          * actually use. This is very generous by incorporating potential
 141          * padding, the terminating 0 and at most 4 chars per UTF-16 code
 142          * point.
 143          */
 144         grow_size = (strlen(str) + 2) * 4;
 145
 146         if (!(tmp = talloc_realloc(NULL, *outbuf, uint8_t,
 147                                          buf_size + grow_size))) {
 148                 DEBUG(0, ("talloc failed\n"));
 149                 return -1;
 150         }
 151
 152         status = srvstr_push((char *)tmp, SVAL(tmp, smb_flg2),
 153                              tmp + buf_size, str, grow_size, flags, &result);
 154
 155         if (!NT_STATUS_IS_OK(status)) {
 156                 DEBUG(0, ("srvstr_push failed\n"));
 157                 return -1;
 158         }
 159
 160         /*
 161          * Ensure we clear out the extra data we have
 162          * grown the buffer by, but not written to.
 163          */
 164         if (buf_size + result < buf_size) {
 165                 return -1;
 166         }
 167         if (grow_size < result) {
 168                 return -1;
 169         }
 170
 171         memset(tmp + buf_size + result, '\0', grow_size - result);
 172
 173         set_message_bcc((char *)tmp, smb_buflen(tmp) + result);
 174
 175         *outbuf = tmp;
 176
 177         return result;
 178 }