source3/smbd/signing.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    SMB Signing Code
   4    Copyright (C) Jeremy Allison 2003.
   5    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2002-2003
   6    Copyright (C) Stefan Metzmacher 2009
   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/globals.h"
  24
  25
  26 /***********************************************************
  27  Called to validate an incoming packet from the client.
  28 ************************************************************/
  29
  30 bool srv_check_sign_mac(struct smbd_server_connection *conn,
  31                         const char *inbuf, uint32_t *seqnum)
  32 {
  33         /* Check if it's a non-session message. */
  34         if(CVAL(inbuf,0)) {
  35                 return true;
  36         }
  37
  38         *seqnum = smb_signing_next_seqnum(conn->signing_state, false);
  39         return smb_signing_check_pdu(conn->signing_state,
  40                                      (const uint8_t *)inbuf,
  41                                      *seqnum);
  42 }
  43
  44 /***********************************************************
  45  Called to sign an outgoing packet to the client.
  46 ************************************************************/
  47
  48 void srv_calculate_sign_mac(struct smbd_server_connection *conn,
  49                             char *outbuf, uint32_t seqnum)
  50 {
  51         /* Check if it's a non-session message. */
  52         if(CVAL(outbuf,0)) {
  53                 return;
  54         }
  55
  56         smb_signing_sign_pdu(conn->signing_state, (uint8_t *)outbuf, seqnum);
  57 }
  58
  59
  60 /***********************************************************
  61  Called to indicate a oneway request
  62 ************************************************************/
  63 void srv_cancel_sign_response(struct smbd_server_connection *conn)
  64 {
  65         smb_signing_cancel_reply(conn->signing_state, true);
  66 }
  67
  68 /***********************************************************
  69  Called by server negprot when signing has been negotiated.
  70 ************************************************************/
  71
  72 bool srv_init_signing(struct smbd_server_connection *conn)
  73 {
  74         bool allowed = true;
  75         bool mandatory = false;
  76
  77         switch (lp_server_signing()) {
  78         case Required:
  79                 mandatory = true;
  80                 break;
  81         case Auto:
  82                 break;
  83         case True:
  84                 break;
  85         case False:
  86                 allowed = false;
  87                 break;
  88         }
  89
  90         conn->signing_state = smb_signing_init(smbd_event_context(),
  91                                                allowed, mandatory);
  92         if (!conn->signing_state) {
  93                 return false;
  94         }
  95
  96         return true;
  97 }
  98
  99 void srv_set_signing_negotiated(struct smbd_server_connection *conn)
 100 {
 101         smb_signing_set_negotiated(conn->signing_state);
 102 }
 103
 104 /***********************************************************
 105  Returns whether signing is active. We can't use sendfile or raw
 106  reads/writes if it is.
 107 ************************************************************/
 108
 109 bool srv_is_signing_active(struct smbd_server_connection *conn)
 110 {
 111         return smb_signing_is_active(conn->signing_state);
 112 }
 113
 114
 115 /***********************************************************
 116  Returns whether signing is negotiated. We can't use it unless it was
 117  in the negprot.
 118 ************************************************************/
 119
 120 bool srv_is_signing_negotiated(struct smbd_server_connection *conn)
 121 {
 122         return smb_signing_is_negotiated(conn->signing_state);
 123 }
 124
 125 /***********************************************************
 126  Turn on signing from this packet onwards.
 127 ************************************************************/
 128
 129 void srv_set_signing(struct smbd_server_connection *conn,
 130                      const DATA_BLOB user_session_key,
 131                      const DATA_BLOB response)
 132 {
 133         bool negotiated;
 134         bool mandatory;
 135
 136         if (!user_session_key.length)
 137                 return;
 138
 139         negotiated = smb_signing_is_negotiated(conn->signing_state);
 140         mandatory = smb_signing_is_mandatory(conn->signing_state);
 141
 142         if (!negotiated && !mandatory) {
 143                 DEBUG(5,("srv_set_signing: signing negotiated = %u, "
 144                          "mandatory_signing = %u. Not allowing smb signing.\n",
 145                          negotiated, mandatory));
 146                 return;
 147         }
 148
 149         if (!smb_signing_activate(conn->signing_state,
 150                                   user_session_key, response)) {
 151                 return;
 152         }
 153
 154         DEBUG(3,("srv_set_signing: turning on SMB signing: "
 155                  "signing negotiated = %u, mandatory_signing = %u.\n",
 156                  negotiated, mandatory));
 157 }
 158