libcli/auth/msrpc_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 "libcli/auth/msrpc_parse.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 NTSTATUS msrpc_gen(TALLOC_CTX *mem_ctx,
  44                DATA_BLOB *blob,
  45                const char *format, ...)
  46 {
  47         int i, j;
  48         bool ret;
  49         va_list ap;
  50         char *s;
  51         uint8_t *b;
  52         int head_size=0, data_size=0;
  53         int head_ofs, data_ofs;
  54         int *intargs;
  55         size_t n;
  56
  57         DATA_BLOB *pointers;
  58
  59         pointers = talloc_array(mem_ctx, DATA_BLOB, strlen(format));
  60         if (!pointers) {
  61                 return NT_STATUS_NO_MEMORY;
  62         }
  63         intargs = talloc_array(pointers, int, strlen(format));
  64         if (!intargs) {
  65                 return NT_STATUS_NO_MEMORY;
  66         }
  67
  68         /* first scan the format to work out the header and body size */
  69         va_start(ap, format);
  70         for (i=0; format[i]; i++) {
  71                 switch (format[i]) {
  72                 case 'U':
  73                         s = va_arg(ap, char *);
  74                         head_size += 8;
  75                         ret = push_ucs2_talloc(
  76                                 pointers,
  77                                 (smb_ucs2_t **)(void *)&pointers[i].data,
  78                                 s, &n);
  79                         if (!ret) {
  80                                 va_end(ap);
  81                                 return map_nt_error_from_unix_common(errno);
  82                         }
  83                         pointers[i].length = n;
  84                         pointers[i].length -= 2;
  85                         data_size += pointers[i].length;
  86                         break;
  87                 case 'A':
  88                         s = va_arg(ap, char *);
  89                         head_size += 8;
  90                         ret = push_ascii_talloc(
  91                                 pointers, (char **)(void *)&pointers[i].data,
  92                                 s, &n);
  93                         if (!ret) {
  94                                 va_end(ap);
  95                                 return map_nt_error_from_unix_common(errno);
  96                         }
  97                         pointers[i].length = n;
  98                         pointers[i].length -= 1;
  99                         data_size += pointers[i].length;
 100                         break;
 101                 case 'a':
 102                         j = va_arg(ap, int);
 103                         intargs[i] = j;
 104                         s = va_arg(ap, char *);
 105                         ret = push_ucs2_talloc(
 106                                 pointers,
 107                                 (smb_ucs2_t **)(void *)&pointers[i].data,
 108                                 s, &n);
 109                         if (!ret) {
 110                                 va_end(ap);
 111                                 return map_nt_error_from_unix_common(errno);
 112                         }
 113                         pointers[i].length = n;
 114                         pointers[i].length -= 2;
 115                         data_size += pointers[i].length + 4;
 116                         break;
 117                 case 'B':
 118                         b = va_arg(ap, uint8_t *);
 119                         head_size += 8;
 120                         pointers[i].data = b;
 121                         pointers[i].length = va_arg(ap, int);
 122                         data_size += pointers[i].length;
 123                         break;
 124                 case 'b':
 125                         b = va_arg(ap, uint8_t *);
 126                         pointers[i].data = b;
 127                         pointers[i].length = va_arg(ap, int);
 128                         head_size += pointers[i].length;
 129                         break;
 130                 case 'd':
 131                         j = va_arg(ap, int);
 132                         intargs[i] = j;
 133                         head_size += 4;
 134                         break;
 135                 case 'C':
 136                         s = va_arg(ap, char *);
 137                         pointers[i].data = (uint8_t *)s;
 138                         pointers[i].length = strlen(s)+1;
 139                         head_size += pointers[i].length;
 140                         break;
 141                 default:
 142                         va_end(ap);
 143                         return NT_STATUS_INVALID_PARAMETER;
 144                 }
 145         }
 146         va_end(ap);
 147
 148         if (head_size + data_size == 0) {
 149                 return NT_STATUS_INVALID_PARAMETER;
 150         }
 151
 152         /* allocate the space, then scan the format again to fill in the values */
 153         *blob = data_blob_talloc(mem_ctx, NULL, head_size + data_size);
 154         if (!blob->data) {
 155                 return NT_STATUS_NO_MEMORY;
 156         }
 157         head_ofs = 0;
 158         data_ofs = head_size;
 159
 160         va_start(ap, format);
 161         for (i=0; format[i]; i++) {
 162                 switch (format[i]) {
 163                 case 'U':
 164                 case 'A':
 165                 case 'B':
 166                         n = pointers[i].length;
 167                         SSVAL(blob->data, head_ofs, n); head_ofs += 2;
 168                         SSVAL(blob->data, head_ofs, n); head_ofs += 2;
 169                         SIVAL(blob->data, head_ofs, data_ofs); head_ofs += 4;
 170                         if (pointers[i].data && n) /* don't follow null pointers... */
 171                                 memcpy(blob->data+data_ofs, pointers[i].data, n);
 172                         data_ofs += n;
 173                         break;
 174                 case 'a':
 175                         j = intargs[i];
 176                         SSVAL(blob->data, data_ofs, j); data_ofs += 2;
 177
 178                         n = pointers[i].length;
 179                         SSVAL(blob->data, data_ofs, n); data_ofs += 2;
 180                         if (n >= 0) {
 181                                 memcpy(blob->data+data_ofs, pointers[i].data, n);
 182                         }
 183                         data_ofs += n;
 184                         break;
 185                 case 'd':
 186                         j = intargs[i];
 187                         SIVAL(blob->data, head_ofs, j);
 188                         head_ofs += 4;
 189                         break;
 190                 case 'b':
 191                         n = pointers[i].length;
 192                         if (pointers[i].data && n) {
 193                                 /* don't follow null pointers... */
 194                                 memcpy(blob->data + head_ofs, pointers[i].data, n);
 195                         }
 196                         head_ofs += n;
 197                         break;
 198                 case 'C':
 199                         n = pointers[i].length;
 200                         memcpy(blob->data + head_ofs, pointers[i].data, n);
 201                         head_ofs += n;
 202                         break;
 203                 default:
 204                         va_end(ap);
 205                         return NT_STATUS_INVALID_PARAMETER;
 206                 }
 207         }
 208         va_end(ap);
 209
 210         talloc_free(pointers);
 211
 212         return NT_STATUS_OK;
 213 }
 214
 215
 216 /* a helpful macro to avoid running over the end of our blob */
 217 #define NEED_DATA(amount) \
 218 if ((head_ofs + amount) > blob->length) { \
 219         va_end(ap); \
 220         return false; \
 221 }
 222
 223 /**
 224   this is a tiny msrpc packet parser. This the the partner of msrpc_gen
 225
 226   format specifiers are:
 227
 228   U = unicode string (output is unix string)
 229   A = ascii string
 230   B = data blob
 231   b = data blob in header
 232   d = word (4 bytes)
 233   C = constant ascii string
 234  */
 235
 236 bool msrpc_parse(TALLOC_CTX *mem_ctx,
 237                  const DATA_BLOB *blob,
 238                  const char *format, ...)
 239 {
 240         int i;
 241         va_list ap;
 242         char **ps, *s;
 243         DATA_BLOB *b;
 244         size_t head_ofs = 0;
 245         uint16_t len1, len2;
 246         uint32_t ptr;
 247         uint32_t *v;
 248         size_t p_len = 1024;
 249         char *p = talloc_array(mem_ctx, char, p_len);
 250         bool ret = true;
 251
 252         if (!p) {
 253                 return false;
 254         }
 255
 256         va_start(ap, format);
 257         for (i=0; format[i]; i++) {
 258                 switch (format[i]) {
 259                 case 'U':
 260                         NEED_DATA(8);
 261                         len1 = SVAL(blob->data, head_ofs); head_ofs += 2;
 262                         len2 = SVAL(blob->data, head_ofs); head_ofs += 2;
 263                         ptr =  IVAL(blob->data, head_ofs); head_ofs += 4;
 264
 265                         ps = va_arg(ap, char **);
 266                         if (len1 == 0 && len2 == 0) {
 267                                 *ps = (char *)discard_const("");
 268                         } else {
 269                                 /* make sure its in the right format - be strict */
 270                                 if ((len1 != len2) || (ptr + len1 < ptr) || (ptr + len1 < len1) || (ptr + len1 > blob->length)) {
 271                                         ret = false;
 272                                         goto cleanup;
 273                                 }
 274                                 if (len1 & 1) {
 275                                         /* if odd length and unicode */
 276                                         ret = false;
 277                                         goto cleanup;
 278                                 }
 279                                 if (blob->data + ptr < (uint8_t *)(uintptr_t)ptr ||
 280                                                 blob->data + ptr < blob->data) {
 281                                         ret = false;
 282                                         goto cleanup;
 283                                 }
 284
 285                                 if (0 < len1) {
 286                                         size_t pull_len;
 287                                         if (!convert_string_talloc(mem_ctx, CH_UTF16, CH_UNIX,
 288                                                                    blob->data + ptr, len1,
 289                                                                    ps, &pull_len)) {
 290                                                 ret = false;
 291                                                 goto cleanup;
 292                                         }
 293                                 } else {
 294                                         (*ps) = (char *)discard_const("");
 295                                 }
 296                         }
 297                         break;
 298                 case 'A':
 299                         NEED_DATA(8);
 300                         len1 = SVAL(blob->data, head_ofs); head_ofs += 2;
 301                         len2 = SVAL(blob->data, head_ofs); head_ofs += 2;
 302                         ptr =  IVAL(blob->data, head_ofs); head_ofs += 4;
 303
 304                         ps = (char **)va_arg(ap, char **);
 305                         /* make sure its in the right format - be strict */
 306                         if (len1 == 0 && len2 == 0) {
 307                                 *ps = (char *)discard_const("");
 308                         } else {
 309                                 if ((len1 != len2) || (ptr + len1 < ptr) || (ptr + len1 < len1) || (ptr + len1 > blob->length)) {
 310                                         ret = false;
 311                                         goto cleanup;
 312                                 }
 313
 314                                 if (blob->data + ptr < (uint8_t *)(uintptr_t)ptr ||
 315                                                 blob->data + ptr < blob->data) {
 316                                         ret = false;
 317                                         goto cleanup;
 318                                 }
 319
 320                                 if (0 < len1) {
 321                                         size_t pull_len;
 322
 323                                         if (!convert_string_talloc(mem_ctx, CH_DOS, CH_UNIX,
 324                                                                    blob->data + ptr, len1,
 325                                                                    ps, &pull_len)) {
 326                                                 ret = false;
 327                                                 goto cleanup;
 328                                         }
 329                                 } else {
 330                                         (*ps) = (char *)discard_const("");
 331                                 }
 332                         }
 333                         break;
 334                 case 'B':
 335                         NEED_DATA(8);
 336                         len1 = SVAL(blob->data, head_ofs); head_ofs += 2;
 337                         len2 = SVAL(blob->data, head_ofs); head_ofs += 2;
 338                         ptr =  IVAL(blob->data, head_ofs); head_ofs += 4;
 339
 340                         b = (DATA_BLOB *)va_arg(ap, void *);
 341                         if (len1 == 0 && len2 == 0) {
 342                                 *b = data_blob_talloc(mem_ctx, NULL, 0);
 343                         } else {
 344                                 /* make sure its in the right format - be strict */
 345                                 if ((len1 != len2) || (ptr + len1 < ptr) || (ptr + len1 < len1) || (ptr + len1 > blob->length)) {
 346                                         ret = false;
 347                                         goto cleanup;
 348                                 }
 349
 350                                 if (blob->data + ptr < (uint8_t *)(uintptr_t)ptr ||
 351                                                 blob->data + ptr < blob->data) {
 352                                         ret = false;
 353                                         goto cleanup;
 354                                 }
 355
 356                                 *b = data_blob_talloc(mem_ctx, blob->data + ptr, len1);
 357                         }
 358                         break;
 359                 case 'b':
 360                         b = (DATA_BLOB *)va_arg(ap, void *);
 361                         len1 = va_arg(ap, unsigned int);
 362                         /* make sure its in the right format - be strict */
 363                         NEED_DATA(len1);
 364                         if (blob->data + head_ofs < (uint8_t *)head_ofs ||
 365                                         blob->data + head_ofs < blob->data) {
 366                                 ret = false;
 367                                 goto cleanup;
 368                         }
 369
 370                         *b = data_blob_talloc(mem_ctx, blob->data + head_ofs, len1);
 371                         head_ofs += len1;
 372                         break;
 373                 case 'd':
 374                         v = va_arg(ap, uint32_t *);
 375                         NEED_DATA(4);
 376                         *v = IVAL(blob->data, head_ofs); head_ofs += 4;
 377                         break;
 378                 case 'C':
 379                         s = va_arg(ap, char *);
 380
 381                         if (blob->data + head_ofs < (uint8_t *)head_ofs ||
 382                                         blob->data + head_ofs < blob->data ||
 383                             (head_ofs + (strlen(s) + 1)) > blob->length) {
 384                                 ret = false;
 385                                 goto cleanup;
 386                         }
 387
 388                         if (memcmp(blob->data + head_ofs, s, strlen(s)+1) != 0) {
 389                                 ret = false;
 390                                 goto cleanup;
 391                         }
 392                         head_ofs += (strlen(s) + 1);
 393
 394                         break;
 395                 }
 396         }
 397
 398 cleanup:
 399         va_end(ap);
 400         talloc_free(p);
 401         return ret;
 402 }