source4/auth/ntlmssp/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 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 "param/param.h"
  24 #include "auth/ntlmssp/msrpc_parse.h"
  25
  26 /*
  27   this is a tiny msrpc packet generator. I am only using this to
  28   avoid tying this code to a particular varient of our rpc code. This
  29   generator is not general enough for all our rpc needs, its just
  30   enough for the spnego/ntlmssp code
  31
  32   format specifiers are:
  33
  34   U = unicode string (input is unix string)
  35   a = address (input is char *unix_string)
  36       (1 byte type, 1 byte length, unicode/ASCII string, all inline)
  37   A = ASCII string (input is unix string)
  38   B = data blob (pointer + length)
  39   b = data blob in header (pointer + length)
  40   D
  41   d = word (4 bytes)
  42   C = constant ascii string
  43  */
  44 bool msrpc_gen(TALLOC_CTX *mem_ctx,
  45                DATA_BLOB *blob,
  46                const char *format, ...)
  47 {
  48         int i;
  49         ssize_t n;
  50         va_list ap;
  51         char *s;
  52         uint8_t *b;
  53         int head_size=0, data_size=0;
  54         int head_ofs, data_ofs;
  55         int *intargs;
  56
  57         DATA_BLOB *pointers;
  58
  59         pointers = talloc_array(mem_ctx, DATA_BLOB, strlen(format));
  60         intargs = talloc_array(pointers, int, strlen(format));
  61
  62         /* first scan the format to work out the header and body size */
  63         va_start(ap, format);
  64         for (i=0; format[i]; i++) {
  65                 switch (format[i]) {
  66                 case 'U':
  67                         s = va_arg(ap, char *);
  68                         head_size += 8;
  69                         n = push_ucs2_talloc(pointers, (void **)&pointers[i].data, s);
  70                         if (n == -1) {
  71                                 return false;
  72                         }
  73                         pointers[i].length = n;
  74                         pointers[i].length -= 2;
  75                         data_size += pointers[i].length;
  76                         break;
  77                 case 'A':
  78                         s = va_arg(ap, char *);
  79                         head_size += 8;
  80                         n = push_ascii_talloc(pointers, (char **)&pointers[i].data, s);
  81                         if (n == -1) {
  82                                 return false;
  83                         }
  84                         pointers[i].length = n;
  85                         pointers[i].length -= 1;
  86                         data_size += pointers[i].length;
  87                         break;
  88                 case 'a':
  89                         n = va_arg(ap, int);
  90                         intargs[i] = n;
  91                         s = va_arg(ap, char *);
  92                         n = push_ucs2_talloc(pointers, (void **)&pointers[i].data, s);
  93                         if (n == -1) {
  94                                 return false;
  95                         }
  96                         pointers[i].length = n;
  97                         pointers[i].length -= 2;
  98                         data_size += pointers[i].length + 4;
  99                         break;
 100                 case 'B':
 101                         b = va_arg(ap, uint8_t *);
 102                         head_size += 8;
 103                         pointers[i].data = b;
 104                         pointers[i].length = va_arg(ap, int);
 105                         data_size += pointers[i].length;
 106                         break;
 107                 case 'b':
 108                         b = va_arg(ap, uint8_t *);
 109                         pointers[i].data = b;
 110                         pointers[i].length = va_arg(ap, int);
 111                         head_size += pointers[i].length;
 112                         break;
 113                 case 'd':
 114                         n = va_arg(ap, int);
 115                         intargs[i] = n;
 116                         head_size += 4;
 117                         break;
 118                 case 'C':
 119                         s = va_arg(ap, char *);
 120                         pointers[i].data = (uint8_t *)s;
 121                         pointers[i].length = strlen(s)+1;
 122                         head_size += pointers[i].length;
 123                         break;
 124                 }
 125         }
 126         va_end(ap);
 127
 128         /* allocate the space, then scan the format again to fill in the values */
 129         *blob = data_blob_talloc(mem_ctx, NULL, head_size + data_size);
 130
 131         head_ofs = 0;
 132         data_ofs = head_size;
 133
 134         va_start(ap, format);
 135         for (i=0; format[i]; i++) {
 136                 switch (format[i]) {
 137                 case 'U':
 138                 case 'A':
 139                 case 'B':
 140                         n = pointers[i].length;
 141                         SSVAL(blob->data, head_ofs, n); head_ofs += 2;
 142                         SSVAL(blob->data, head_ofs, n); head_ofs += 2;
 143                         SIVAL(blob->data, head_ofs, data_ofs); head_ofs += 4;
 144                         if (pointers[i].data && n) /* don't follow null pointers... */
 145                                 memcpy(blob->data+data_ofs, pointers[i].data, n);
 146                         data_ofs += n;
 147                         break;
 148                 case 'a':
 149                         n = intargs[i];
 150                         SSVAL(blob->data, data_ofs, n); data_ofs += 2;
 151
 152                         n = pointers[i].length;
 153                         SSVAL(blob->data, data_ofs, n); data_ofs += 2;
 154                         if (n >= 0) {
 155                                 memcpy(blob->data+data_ofs, pointers[i].data, n);
 156                         }
 157                         data_ofs += n;
 158                         break;
 159                 case 'd':
 160                         n = intargs[i];
 161                         SIVAL(blob->data, head_ofs, n);
 162                         head_ofs += 4;
 163                         break;
 164                 case 'b':
 165                         n = pointers[i].length;
 166                         memcpy(blob->data + head_ofs, pointers[i].data, n);
 167                         head_ofs += n;
 168                         break;
 169                 case 'C':
 170                         n = pointers[i].length;
 171                         memcpy(blob->data + head_ofs, pointers[i].data, n);
 172                         head_ofs += n;
 173                         break;
 174                 }
 175         }
 176         va_end(ap);
 177
 178         talloc_free(pointers);
 179
 180         return true;
 181 }
 182
 183
 184 /* a helpful macro to avoid running over the end of our blob */
 185 #define NEED_DATA(amount) \
 186 if ((head_ofs + amount) > blob->length) { \
 187         return false; \
 188 }
 189
 190 /*
 191   this is a tiny msrpc packet parser. This the the partner of msrpc_gen
 192
 193   format specifiers are:
 194
 195   U = unicode string (output is unix string)
 196   A = ascii string
 197   B = data blob
 198   b = data blob in header
 199   d = word (4 bytes)
 200   C = constant ascii string
 201  */
 202
 203 bool msrpc_parse(TALLOC_CTX *mem_ctx,
 204                  struct smb_iconv_convenience *iconv_convenience,
 205                  const DATA_BLOB *blob,
 206                  const char *format, ...)
 207 {
 208         int i;
 209         va_list ap;
 210         const char **ps, *s;
 211         DATA_BLOB *b;
 212         size_t head_ofs = 0;
 213         uint16_t len1, len2;
 214         uint32_t ptr;
 215         uint32_t *v;
 216         size_t p_len = 1024;
 217         char *p = talloc_array(mem_ctx, char, p_len);
 218         bool ret = true;
 219
 220         va_start(ap, format);
 221         for (i=0; format[i]; i++) {
 222                 switch (format[i]) {
 223                 case 'U':
 224                         NEED_DATA(8);
 225                         len1 = SVAL(blob->data, head_ofs); head_ofs += 2;
 226                         len2 = SVAL(blob->data, head_ofs); head_ofs += 2;
 227                         ptr =  IVAL(blob->data, head_ofs); head_ofs += 4;
 228
 229                         ps = (const char **)va_arg(ap, char **);
 230                         if (len1 == 0 && len2 == 0) {
 231                                 *ps = "";
 232                         } else {
 233                                 /* make sure its in the right format - be strict */
 234                                 if ((len1 != len2) || (ptr + len1 < ptr) || (ptr + len1 < len1) || (ptr + len1 > blob->length)) {
 235                                         ret = false;
 236                                         goto cleanup;
 237                                 }
 238                                 if (len1 & 1) {
 239                                         /* if odd length and unicode */
 240                                         ret = false;
 241                                         goto cleanup;
 242                                 }
 243                                 if (blob->data + ptr < (uint8_t *)(uintptr_t)ptr ||
 244                                                 blob->data + ptr < blob->data) {
 245                                         ret = false;
 246                                         goto cleanup;
 247                                 }
 248
 249                                 if (0 < len1) {
 250                                         pull_string(p, blob->data + ptr, p_len,
 251                                                     len1, STR_UNICODE|STR_NOALIGN);
 252                                         (*ps) = talloc_strdup(mem_ctx, p);
 253                                         if (!(*ps)) {
 254                                                 ret = false;
 255                                                 goto cleanup;
 256                                         }
 257                                 } else {
 258                                         (*ps) = "";
 259                                 }
 260                         }
 261                         break;
 262                 case 'A':
 263                         NEED_DATA(8);
 264                         len1 = SVAL(blob->data, head_ofs); head_ofs += 2;
 265                         len2 = SVAL(blob->data, head_ofs); head_ofs += 2;
 266                         ptr =  IVAL(blob->data, head_ofs); head_ofs += 4;
 267
 268                         ps = (const char **)va_arg(ap, char **);
 269                         /* make sure its in the right format - be strict */
 270                         if (len1 == 0 && len2 == 0) {
 271                                 *ps = "";
 272                         } else {
 273                                 if ((len1 != len2) || (ptr + len1 < ptr) || (ptr + len1 < len1) || (ptr + len1 > blob->length)) {
 274                                         ret = false;
 275                                         goto cleanup;
 276                                 }
 277
 278                                 if (blob->data + ptr < (uint8_t *)(uintptr_t)ptr ||
 279                                                 blob->data + ptr < blob->data) {
 280                                         ret = false;
 281                                         goto cleanup;
 282                                 }
 283
 284                                 if (0 < len1) {
 285                                         pull_string(p, blob->data + ptr, p_len,
 286                                                     len1, STR_ASCII|STR_NOALIGN);
 287                                         (*ps) = talloc_strdup(mem_ctx, p);
 288                                         if (!(*ps)) {
 289                                                 ret = false;
 290                                                 goto cleanup;
 291                                         }
 292                                 } else {
 293                                         (*ps) = "";
 294                                 }
 295                         }
 296                         break;
 297                 case 'B':
 298                         NEED_DATA(8);
 299                         len1 = SVAL(blob->data, head_ofs); head_ofs += 2;
 300                         len2 = SVAL(blob->data, head_ofs); head_ofs += 2;
 301                         ptr =  IVAL(blob->data, head_ofs); head_ofs += 4;
 302
 303                         b = (DATA_BLOB *)va_arg(ap, void *);
 304                         if (len1 == 0 && len2 == 0) {
 305                                 *b = data_blob_talloc(mem_ctx, NULL, 0);
 306                         } else {
 307                                 /* make sure its in the right format - be strict */
 308                                 if ((len1 != len2) || (ptr + len1 < ptr) || (ptr + len1 < len1) || (ptr + len1 > blob->length)) {
 309                                         ret = false;
 310                                         goto cleanup;
 311                                 }
 312
 313                                 if (blob->data + ptr < (uint8_t *)(uintptr_t)ptr ||
 314                                                 blob->data + ptr < blob->data) {
 315                                         ret = false;
 316                                         goto cleanup;
 317                                 }
 318
 319                                 *b = data_blob_talloc(mem_ctx, blob->data + ptr, len1);
 320                         }
 321                         break;
 322                 case 'b':
 323                         b = (DATA_BLOB *)va_arg(ap, void *);
 324                         len1 = va_arg(ap, uint_t);
 325                         /* make sure its in the right format - be strict */
 326                         NEED_DATA(len1);
 327                         if (blob->data + head_ofs < (uint8_t *)head_ofs ||
 328                                         blob->data + head_ofs < blob->data) {
 329                                 ret = false;
 330                                 goto cleanup;
 331                         }
 332
 333                         *b = data_blob_talloc(mem_ctx, blob->data + head_ofs, len1);
 334                         head_ofs += len1;
 335                         break;
 336                 case 'd':
 337                         v = va_arg(ap, uint32_t *);
 338                         NEED_DATA(4);
 339                         *v = IVAL(blob->data, head_ofs); head_ofs += 4;
 340                         break;
 341                 case 'C':
 342                         s = va_arg(ap, char *);
 343
 344                         if (blob->data + head_ofs < (uint8_t *)head_ofs ||
 345                                         blob->data + head_ofs < blob->data) {
 346                                 ret = false;
 347                                 goto cleanup;
 348                         }
 349
 350                         head_ofs += pull_string(p,
 351                                         blob->data+head_ofs, p_len,
 352                                         blob->length - head_ofs,
 353                                         STR_ASCII|STR_TERMINATE);
 354                         if (strcmp(s, p) != 0) {
 355                                 ret = false;
 356                                 goto cleanup;
 357                         }
 358                         break;
 359                 }
 360         }
 361
 362 cleanup:
 363         va_end(ap);
 364         talloc_free(p);
 365         return ret;
 366 }