source3/registry/reg_parse_prs.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Samba memory buffer functions
   4    Copyright (C) Andrew Tridgell              1992-1997
   5    Copyright (C) Luke Kenneth Casson Leighton 1996-1997
   6    Copyright (C) Jeremy Allison               1999
   7    Copyright (C) Andrew Bartlett              2003.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 #include "includes.h"
  24 #include "reg_parse_prs.h"
  25 #include "rpc_dce.h"
  26
  27 #undef DBGC_CLASS
  28 #define DBGC_CLASS DBGC_RPC_PARSE
  29
  30 static const char *tab_depth(int level, int depth)
  31 {
  32         if( CHECK_DEBUGLVL(level) ) {
  33                 dbgtext("%*s", depth*4, "");
  34         }
  35         return "";
  36 }
  37
  38 /*******************************************************************
  39  Debug output for parsing info
  40
  41  XXXX side-effect of this function is to increase the debug depth XXXX.
  42
  43 ********************************************************************/
  44
  45 void prs_debug(prs_struct *ps, int depth, const char *desc, const char *fn_name)
  46 {
  47         DEBUG(5+depth, ("%s%06x %s %s\n", tab_depth(5+depth,depth), ps->data_offset, fn_name, desc));
  48 }
  49
  50 /**
  51  * Initialise an expandable parse structure.
  52  *
  53  * @param size Initial buffer size.  If >0, a new buffer will be
  54  * created with talloc().
  55  *
  56  * @return False if allocation fails, otherwise True.
  57  **/
  58
  59 bool prs_init(prs_struct *ps, uint32_t size, TALLOC_CTX *ctx, bool io)
  60 {
  61         ZERO_STRUCTP(ps);
  62         ps->io = io;
  63         ps->bigendian_data = RPC_LITTLE_ENDIAN;
  64         ps->align = RPC_PARSE_ALIGN;
  65         ps->is_dynamic = False;
  66         ps->data_offset = 0;
  67         ps->buffer_size = 0;
  68         ps->data_p = NULL;
  69         ps->mem_ctx = ctx;
  70
  71         if (size != 0) {
  72                 ps->buffer_size = size;
  73                 ps->data_p = (char *)talloc_zero_size(ps->mem_ctx, size);
  74                 if(ps->data_p == NULL) {
  75                         DEBUG(0,("prs_init: talloc fail for %u bytes.\n", (unsigned int)size));
  76                         return False;
  77                 }
  78                 ps->is_dynamic = True; /* We own this memory. */
  79         } else if (MARSHALLING(ps)) {
  80                 /* If size is zero and we're marshalling we should allocate memory on demand. */
  81                 ps->is_dynamic = True;
  82         }
  83
  84         return True;
  85 }
  86
  87 /*******************************************************************
  88  Delete the memory in a parse structure - if we own it.
  89
  90  NOTE: Contrary to the somewhat confusing naming, this function is not
  91        intended for freeing memory allocated by prs_alloc_mem().
  92        That memory is also attached to the talloc context given by
  93        ps->mem_ctx, but is only freed when that talloc context is
  94        freed. prs_mem_free() is used to delete "dynamic" memory
  95        allocated in marshalling/unmarshalling.
  96  ********************************************************************/
  97
  98 void prs_mem_free(prs_struct *ps)
  99 {
 100         if(ps->is_dynamic) {
 101                 TALLOC_FREE(ps->data_p);
 102         }
 103         ps->is_dynamic = False;
 104         ps->buffer_size = 0;
 105         ps->data_offset = 0;
 106 }
 107
 108 /*******************************************************************
 109  Allocate memory when unmarshalling... Always zero clears.
 110  ********************************************************************/
 111
 112 #if defined(PARANOID_MALLOC_CHECKER)
 113 char *prs_alloc_mem_(prs_struct *ps, size_t size, unsigned int count)
 114 #else
 115 char *prs_alloc_mem(prs_struct *ps, size_t size, unsigned int count)
 116 #endif
 117 {
 118         char *ret = NULL;
 119
 120         if (size && count) {
 121                 /* We can't call the type-safe version here. */
 122                 ret = (char *)_talloc_zero_array(ps->mem_ctx, size, count,
 123                                                  "parse_prs");
 124         }
 125         return ret;
 126 }
 127
 128 /*******************************************************************
 129  Return the current talloc context we're using.
 130  ********************************************************************/
 131
 132 TALLOC_CTX *prs_get_mem_context(prs_struct *ps)
 133 {
 134         return ps->mem_ctx;
 135 }
 136
 137 /*******************************************************************
 138  Attempt, if needed, to grow a data buffer.
 139  Also depends on the data stream mode (io).
 140  ********************************************************************/
 141
 142 bool prs_grow(prs_struct *ps, uint32_t extra_space)
 143 {
 144         uint32_t new_size;
 145
 146         ps->grow_size = MAX(ps->grow_size, ps->data_offset + extra_space);
 147
 148         if(ps->data_offset + extra_space <= ps->buffer_size)
 149                 return True;
 150
 151         /*
 152          * We cannot grow the buffer if we're not reading
 153          * into the prs_struct, or if we don't own the memory.
 154          */
 155
 156         if(UNMARSHALLING(ps) || !ps->is_dynamic) {
 157                 DEBUG(0,("prs_grow: Buffer overflow - unable to expand buffer by %u bytes.\n",
 158                                 (unsigned int)extra_space));
 159                 return False;
 160         }
 161
 162         /*
 163          * Decide how much extra space we really need.
 164          */
 165
 166         extra_space -= (ps->buffer_size - ps->data_offset);
 167         if(ps->buffer_size == 0) {
 168
 169                 /*
 170                  * Start with 128 bytes (arbitrary value), enough for small rpc
 171                  * requests
 172                  */
 173                 new_size = MAX(128, extra_space);
 174
 175                 ps->data_p = (char *)talloc_zero_size(ps->mem_ctx, new_size);
 176                 if(ps->data_p == NULL) {
 177                         DEBUG(0,("prs_grow: talloc failure for size %u.\n", (unsigned int)new_size));
 178                         return False;
 179                 }
 180         } else {
 181                 /*
 182                  * If the current buffer size is bigger than the space needed,
 183                  * just double it, else add extra_space. Always keep 64 bytes
 184                  * more, so that after we added a large blob we don't have to
 185                  * realloc immediately again.
 186                  */
 187                 new_size = MAX(ps->buffer_size*2,
 188                                ps->buffer_size + extra_space + 64);
 189
 190                 ps->data_p = talloc_realloc(ps->mem_ctx,
 191                                                 ps->data_p,
 192                                                 char,
 193                                                 new_size);
 194                 if (ps->data_p == NULL) {
 195                         DEBUG(0,("prs_grow: Realloc failure for size %u.\n",
 196                                 (unsigned int)new_size));
 197                         return False;
 198                 }
 199
 200                 memset(&ps->data_p[ps->buffer_size], '\0', (size_t)(new_size - ps->buffer_size));
 201         }
 202         ps->buffer_size = new_size;
 203
 204         return True;
 205 }
 206
 207 /*******************************************************************
 208  Get the data pointer (external interface).
 209 ********************************************************************/
 210
 211 char *prs_data_p(prs_struct *ps)
 212 {
 213         return ps->data_p;
 214 }
 215
 216 /*******************************************************************
 217  Get the current data size (external interface).
 218  ********************************************************************/
 219
 220 uint32_t prs_data_size(prs_struct *ps)
 221 {
 222         return ps->buffer_size;
 223 }
 224
 225 /*******************************************************************
 226  Fetch the current offset (external interface).
 227  ********************************************************************/
 228
 229 uint32_t prs_offset(prs_struct *ps)
 230 {
 231         return ps->data_offset;
 232 }
 233
 234 /*******************************************************************
 235  Set the current offset (external interface).
 236  ********************************************************************/
 237
 238 bool prs_set_offset(prs_struct *ps, uint32_t offset)
 239 {
 240         if ((offset > ps->data_offset)
 241             && !prs_grow(ps, offset - ps->data_offset)) {
 242                 return False;
 243         }
 244
 245         ps->data_offset = offset;
 246         return True;
 247 }
 248
 249 /*******************************************************************
 250  Append the data from a buffer into a parse_struct.
 251  ********************************************************************/
 252
 253 bool prs_copy_data_in(prs_struct *dst, const char *src, uint32_t len)
 254 {
 255         if (len == 0)
 256                 return True;
 257
 258         if(!prs_grow(dst, len))
 259                 return False;
 260
 261         memcpy(&dst->data_p[dst->data_offset], src, (size_t)len);
 262         dst->data_offset += len;
 263
 264         return True;
 265 }
 266
 267 /*******************************************************************
 268  Align the data_len to a multiple of align bytes - filling with
 269  zeros.
 270  ********************************************************************/
 271
 272 bool prs_align(prs_struct *ps)
 273 {
 274         uint32_t mod = ps->data_offset & (ps->align-1);
 275
 276         if (ps->align != 0 && mod != 0) {
 277                 uint32_t extra_space = (ps->align - mod);
 278                 if(!prs_grow(ps, extra_space))
 279                         return False;
 280                 memset(&ps->data_p[ps->data_offset], '\0', (size_t)extra_space);
 281                 ps->data_offset += extra_space;
 282         }
 283
 284         return True;
 285 }
 286
 287 /******************************************************************
 288  Align on a 8 byte boundary
 289  *****************************************************************/
 290
 291 bool prs_align_uint64(prs_struct *ps)
 292 {
 293         bool ret;
 294         uint8_t old_align = ps->align;
 295
 296         ps->align = 8;
 297         ret = prs_align(ps);
 298         ps->align = old_align;
 299
 300         return ret;
 301 }
 302
 303 /*******************************************************************
 304  Ensure we can read/write to a given offset.
 305  ********************************************************************/
 306
 307 char *prs_mem_get(prs_struct *ps, uint32_t extra_size)
 308 {
 309         if(UNMARSHALLING(ps)) {
 310                 /*
 311                  * If reading, ensure that we can read the requested size item.
 312                  */
 313                 if (ps->data_offset + extra_size > ps->buffer_size) {
 314                         DEBUG(0,("prs_mem_get: reading data of size %u would overrun "
 315                                 "buffer by %u bytes.\n",
 316                                 (unsigned int)extra_size,
 317                                 (unsigned int)(ps->data_offset + extra_size - ps->buffer_size) ));
 318                         return NULL;
 319                 }
 320         } else {
 321                 /*
 322                  * Writing - grow the buffer if needed.
 323                  */
 324                 if(!prs_grow(ps, extra_size))
 325                         return NULL;
 326         }
 327         return &ps->data_p[ps->data_offset];
 328 }
 329
 330 /*******************************************************************
 331  Change the struct type.
 332  ********************************************************************/
 333
 334 void prs_switch_type(prs_struct *ps, bool io)
 335 {
 336         if ((ps->io ^ io) == True)
 337                 ps->io=io;
 338 }
 339
 340 /*******************************************************************
 341  Stream a uint16.
 342  ********************************************************************/
 343
 344 bool prs_uint16(const char *name, prs_struct *ps, int depth, uint16_t *data16)
 345 {
 346         char *q = prs_mem_get(ps, sizeof(uint16_t));
 347         if (q == NULL)
 348                 return False;
 349
 350         if (UNMARSHALLING(ps)) {
 351                 if (ps->bigendian_data)
 352                         *data16 = RSVAL(q,0);
 353                 else
 354                         *data16 = SVAL(q,0);
 355         } else {
 356                 if (ps->bigendian_data)
 357                         RSSVAL(q,0,*data16);
 358                 else
 359                         SSVAL(q,0,*data16);
 360         }
 361
 362         DEBUGADD(5,("%s%04x %s: %04x\n", tab_depth(5,depth), ps->data_offset, name, *data16));
 363
 364         ps->data_offset += sizeof(uint16_t);
 365
 366         return True;
 367 }
 368
 369 /*******************************************************************
 370  Stream a uint32.
 371  ********************************************************************/
 372
 373 bool prs_uint32(const char *name, prs_struct *ps, int depth, uint32_t *data32)
 374 {
 375         char *q = prs_mem_get(ps, sizeof(uint32_t));
 376         if (q == NULL)
 377                 return False;
 378
 379         if (UNMARSHALLING(ps)) {
 380                 if (ps->bigendian_data)
 381                         *data32 = RIVAL(q,0);
 382                 else
 383                         *data32 = IVAL(q,0);
 384         } else {
 385                 if (ps->bigendian_data)
 386                         RSIVAL(q,0,*data32);
 387                 else
 388                         SIVAL(q,0,*data32);
 389         }
 390
 391         DEBUGADD(5,("%s%04x %s: %08x\n", tab_depth(5,depth), ps->data_offset, name, *data32));
 392
 393         ps->data_offset += sizeof(uint32_t);
 394
 395         return True;
 396 }
 397
 398 /*******************************************************************
 399  Stream a uint64_struct
 400  ********************************************************************/
 401 bool prs_uint64(const char *name, prs_struct *ps, int depth, uint64_t *data64)
 402 {
 403         if (UNMARSHALLING(ps)) {
 404                 uint32_t high, low;
 405
 406                 if (!prs_uint32(name, ps, depth+1, &low))
 407                         return False;
 408
 409                 if (!prs_uint32(name, ps, depth+1, &high))
 410                         return False;
 411
 412                 *data64 = ((uint64_t)high << 32) + low;
 413
 414                 return True;
 415         } else {
 416                 uint32_t high = (*data64) >> 32, low = (*data64) & 0xFFFFFFFF;
 417                 return prs_uint32(name, ps, depth+1, &low) &&
 418                            prs_uint32(name, ps, depth+1, &high);
 419         }
 420 }
 421
 422 /******************************************************************
 423  Stream an array of uint8s. Length is number of uint8s.
 424  ********************************************************************/
 425
 426 bool prs_uint8s(bool charmode, const char *name, prs_struct *ps, int depth, uint8_t *data8s, int len)
 427 {
 428         int i;
 429         char *q = prs_mem_get(ps, len);
 430         if (q == NULL)
 431                 return False;
 432
 433         if (UNMARSHALLING(ps)) {
 434                 for (i = 0; i < len; i++)
 435                         data8s[i] = CVAL(q,i);
 436         } else {
 437                 for (i = 0; i < len; i++)
 438                         SCVAL(q, i, data8s[i]);
 439         }
 440
 441         DEBUGADD(5,("%s%04x %s: ", tab_depth(5,depth), ps->data_offset ,name));
 442         if (charmode)
 443                 print_asc(5, (unsigned char*)data8s, len);
 444         else {
 445                 for (i = 0; i < len; i++)
 446                         DEBUGADD(5,("%02x ", data8s[i]));
 447         }
 448         DEBUGADD(5,("\n"));
 449
 450         ps->data_offset += len;
 451
 452         return True;
 453 }