source/libsmb/ntlmssp_parse.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    simple kerberos5/SPNEGO routines
   4    Copyright (C) Andrew Tridgell 2001
   5    Copyright (C) Jim McDonough <jmcd@us.ibm.com> 2002
   6    Copyright (C) Andrew Bartlett 2002-2003
   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 2 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, write to the Free Software
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22
  23 #include "includes.h"
  24
  25 /*
  26   this is a tiny msrpc packet generator. I am only using this to
  27   avoid tying this code to a particular varient of our rpc code. This
  28   generator is not general enough for all our rpc needs, its just
  29   enough for the spnego/ntlmssp code
  30
  31   format specifiers are:
  32
  33   U = unicode string (input is unix string)
  34   a = address (input is char *unix_string)
  35       (1 byte type, 1 byte length, unicode/ASCII string, all inline)
  36   A = ASCII string (input is unix string)
  37   B = data blob (pointer + length)
  38   b = data blob in header (pointer + length)
  39   D
  40   d = word (4 bytes)
  41   C = constant ascii string
  42  */
  43 BOOL msrpc_gen(DATA_BLOB *blob,
  44                const char *format, ...)
  45 {
  46         int i, n;
  47         va_list ap;
  48         char *s;
  49         uint8 *b;
  50         int head_size=0, data_size=0;
  51         int head_ofs, data_ofs;
  52
  53         /* first scan the format to work out the header and body size */
  54         va_start(ap, format);
  55         for (i=0; format[i]; i++) {
  56                 switch (format[i]) {
  57                 case 'U':
  58                         s = va_arg(ap, char *);
  59                         head_size += 8;
  60                         data_size += str_charnum(s) * 2;
  61                         break;
  62                 case 'A':
  63                         s = va_arg(ap, char *);
  64                         head_size += 8;
  65                         data_size += str_ascii_charnum(s);
  66                         break;
  67                 case 'a':
  68                         n = va_arg(ap, int);
  69                         s = va_arg(ap, char *);
  70                         data_size += (str_charnum(s) * 2) + 4;
  71                         break;
  72                 case 'B':
  73                         b = va_arg(ap, uint8 *);
  74                         head_size += 8;
  75                         data_size += va_arg(ap, int);
  76                         break;
  77                 case 'b':
  78                         b = va_arg(ap, uint8 *);
  79                         head_size += va_arg(ap, int);
  80                         break;
  81                 case 'd':
  82                         n = va_arg(ap, int);
  83                         head_size += 4;
  84                         break;
  85                 case 'C':
  86                         s = va_arg(ap, char *);
  87                         head_size += str_charnum(s) + 1;
  88                         break;
  89                 }
  90         }
  91         va_end(ap);
  92
  93         /* allocate the space, then scan the format again to fill in the values */
  94         *blob = data_blob(NULL, head_size + data_size);
  95
  96         head_ofs = 0;
  97         data_ofs = head_size;
  98
  99         va_start(ap, format);
 100         for (i=0; format[i]; i++) {
 101                 switch (format[i]) {
 102                 case 'U':
 103                         s = va_arg(ap, char *);
 104                         n = str_charnum(s);
 105                         SSVAL(blob->data, head_ofs, n*2); head_ofs += 2;
 106                         SSVAL(blob->data, head_ofs, n*2); head_ofs += 2;
 107                         SIVAL(blob->data, head_ofs, data_ofs); head_ofs += 4;
 108                         push_string(NULL, blob->data+data_ofs, s, n*2, STR_UNICODE|STR_NOALIGN);
 109                         data_ofs += n*2;
 110                         break;
 111                 case 'A':
 112                         s = va_arg(ap, char *);
 113                         n = str_ascii_charnum(s);
 114                         SSVAL(blob->data, head_ofs, n); head_ofs += 2;
 115                         SSVAL(blob->data, head_ofs, n); head_ofs += 2;
 116                         SIVAL(blob->data, head_ofs, data_ofs); head_ofs += 4;
 117                         push_string(NULL, blob->data+data_ofs, s, n, STR_ASCII|STR_NOALIGN);
 118                         data_ofs += n;
 119                         break;
 120                 case 'a':
 121                         n = va_arg(ap, int);
 122                         SSVAL(blob->data, data_ofs, n); data_ofs += 2;
 123                         s = va_arg(ap, char *);
 124                         n = str_charnum(s);
 125                         SSVAL(blob->data, data_ofs, n*2); data_ofs += 2;
 126                         if (0 < n) {
 127                                 push_string(NULL, blob->data+data_ofs, s, n*2,
 128                                             STR_UNICODE|STR_NOALIGN);
 129                         }
 130                         data_ofs += n*2;
 131                         break;
 132
 133                 case 'B':
 134                         b = va_arg(ap, uint8 *);
 135                         n = va_arg(ap, int);
 136                         SSVAL(blob->data, head_ofs, n); head_ofs += 2;
 137                         SSVAL(blob->data, head_ofs, n); head_ofs += 2;
 138                         SIVAL(blob->data, head_ofs, data_ofs); head_ofs += 4;
 139                         if (n && b) /* don't follow null pointers... */
 140                                 memcpy(blob->data+data_ofs, b, n);
 141                         data_ofs += n;
 142                         break;
 143                 case 'd':
 144                         n = va_arg(ap, int);
 145                         SIVAL(blob->data, head_ofs, n); head_ofs += 4;
 146                         break;
 147                 case 'b':
 148                         b = va_arg(ap, uint8 *);
 149                         n = va_arg(ap, int);
 150                         memcpy(blob->data + head_ofs, b, n);
 151                         head_ofs += n;
 152                         break;
 153                 case 'C':
 154                         s = va_arg(ap, char *);
 155                         head_ofs += push_string(NULL, blob->data+head_ofs, s, -1,
 156                                                 STR_ASCII|STR_TERMINATE);
 157                         break;
 158                 }
 159         }
 160         va_end(ap);
 161
 162         return True;
 163 }
 164
 165
 166 /* a helpful macro to avoid running over the end of our blob */
 167 #define NEED_DATA(amount) \
 168 if ((head_ofs + amount) > blob->length) { \
 169         return False; \
 170 }
 171
 172 /*
 173   this is a tiny msrpc packet parser. This the the partner of msrpc_gen
 174
 175   format specifiers are:
 176
 177   U = unicode string (output is unix string)
 178   A = ascii string
 179   B = data blob
 180   b = data blob in header
 181   d = word (4 bytes)
 182   C = constant ascii string
 183  */
 184
 185 BOOL msrpc_parse(const DATA_BLOB *blob,
 186                  const char *format, ...)
 187 {
 188         int i;
 189         va_list ap;
 190         char **ps, *s;
 191         DATA_BLOB *b;
 192         size_t head_ofs = 0;
 193         uint16 len1, len2;
 194         uint32 ptr;
 195         uint32 *v;
 196         pstring p;
 197
 198         va_start(ap, format);
 199         for (i=0; format[i]; i++) {
 200                 switch (format[i]) {
 201                 case 'U':
 202                         NEED_DATA(8);
 203                         len1 = SVAL(blob->data, head_ofs); head_ofs += 2;
 204                         len2 = SVAL(blob->data, head_ofs); head_ofs += 2;
 205                         ptr =  IVAL(blob->data, head_ofs); head_ofs += 4;
 206
 207                         ps = va_arg(ap, char **);
 208                         if (len1 == 0 && len2 == 0) {
 209                                 *ps = smb_xstrdup("");
 210                         } else {
 211                                 /* make sure its in the right format - be strict */
 212                                 if ((len1 != len2) || (ptr + len1 < ptr) || (ptr + len1 < len1) || (ptr + len1 > blob->length)) {
 213                                         return False;
 214                                 }
 215                                 if (len1 & 1) {
 216                                         /* if odd length and unicode */
 217                                         return False;
 218                                 }
 219
 220                                 if (0 < len1) {
 221                                         pull_string(NULL, p, blob->data + ptr, sizeof(p),
 222                                                     len1,
 223                                                     STR_UNICODE|STR_NOALIGN);
 224                                         (*ps) = smb_xstrdup(p);
 225                                 } else {
 226                                         (*ps) = smb_xstrdup("");
 227                                 }
 228                         }
 229                         break;
 230                 case 'A':
 231                         NEED_DATA(8);
 232                         len1 = SVAL(blob->data, head_ofs); head_ofs += 2;
 233                         len2 = SVAL(blob->data, head_ofs); head_ofs += 2;
 234                         ptr =  IVAL(blob->data, head_ofs); head_ofs += 4;
 235
 236                         ps = va_arg(ap, char **);
 237                         /* make sure its in the right format - be strict */
 238                         if (len1 == 0 && len2 == 0) {
 239                                 *ps = smb_xstrdup("");
 240                         } else {
 241                                 if ((len1 != len2) || (ptr + len1 < ptr) || (ptr + len1 < len1) || (ptr + len1 > blob->length)) {
 242                                         return False;
 243                                 }
 244
 245                                 if (0 < len1) {
 246                                         pull_string(NULL, p, blob->data + ptr, sizeof(p),
 247                                                     len1,
 248                                                     STR_ASCII|STR_NOALIGN);
 249                                         (*ps) = smb_xstrdup(p);
 250                                 } else {
 251                                         (*ps) = smb_xstrdup("");
 252                                 }
 253                         }
 254                         break;
 255                 case 'B':
 256                         NEED_DATA(8);
 257                         len1 = SVAL(blob->data, head_ofs); head_ofs += 2;
 258                         len2 = SVAL(blob->data, head_ofs); head_ofs += 2;
 259                         ptr =  IVAL(blob->data, head_ofs); head_ofs += 4;
 260
 261                         b = (DATA_BLOB *)va_arg(ap, void *);
 262                         if (len1 == 0 && len2 == 0) {
 263                                 *b = data_blob(NULL, 0);
 264                         } else {
 265                                 /* make sure its in the right format - be strict */
 266                                 if ((len1 != len2) || (ptr + len1 < ptr) || (ptr + len1 < len1) || (ptr + len1 > blob->length)) {
 267                                         return False;
 268                                 }
 269                                 *b = data_blob(blob->data + ptr, len1);
 270                         }
 271                         break;
 272                 case 'b':
 273                         b = (DATA_BLOB *)va_arg(ap, void *);
 274                         len1 = va_arg(ap, unsigned);
 275                         /* make sure its in the right format - be strict */
 276                         NEED_DATA(len1);
 277                         *b = data_blob(blob->data + head_ofs, len1);
 278                         head_ofs += len1;
 279                         break;
 280                 case 'd':
 281                         v = va_arg(ap, uint32 *);
 282                         NEED_DATA(4);
 283                         *v = IVAL(blob->data, head_ofs); head_ofs += 4;
 284                         break;
 285                 case 'C':
 286                         s = va_arg(ap, char *);
 287                         head_ofs += pull_string(NULL, p, blob->data+head_ofs, sizeof(p),
 288                                                 blob->length - head_ofs,
 289                                                 STR_ASCII|STR_TERMINATE);
 290                         if (strcmp(s, p) != 0) {
 291                                 return False;
 292                         }
 293                         break;
 294                 }
 295         }
 296         va_end(ap);
 297
 298         return True;
 299 }