source3/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 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
  24 /*
  25   this is a tiny msrpc packet generator. I am only using this to
  26   avoid tying this code to a particular varient of our rpc code. This
  27   generator is not general enough for all our rpc needs, its just
  28   enough for the spnego/ntlmssp code
  29
  30   format specifiers are:
  31
  32   U = unicode string (input is unix string)
  33   a = address (input is char *unix_string)
  34       (1 byte type, 1 byte length, unicode/ASCII string, all inline)
  35   A = ASCII string (input is unix string)
  36   B = data blob (pointer + length)
  37   b = data blob in header (pointer + length)
  38   D
  39   d = word (4 bytes)
  40   C = constant ascii string
  41  */
  42 bool msrpc_gen(DATA_BLOB *blob,
  43                const char *format, ...)
  44 {
  45         int i, n;
  46         va_list ap;
  47         char *s;
  48         uint8 *b;
  49         int head_size=0, data_size=0;
  50         int head_ofs, data_ofs;
  51
  52         /* first scan the format to work out the header and body size */
  53         va_start(ap, format);
  54         for (i=0; format[i]; i++) {
  55                 switch (format[i]) {
  56                 case 'U':
  57                         s = va_arg(ap, char *);
  58                         head_size += 8;
  59                         data_size += str_charnum(s) * 2;
  60                         break;
  61                 case 'A':
  62                         s = va_arg(ap, char *);
  63                         head_size += 8;
  64                         data_size += str_ascii_charnum(s);
  65                         break;
  66                 case 'a':
  67                         n = va_arg(ap, int);
  68                         s = va_arg(ap, char *);
  69                         data_size += (str_charnum(s) * 2) + 4;
  70                         break;
  71                 case 'B':
  72                         b = va_arg(ap, uint8 *);
  73                         head_size += 8;
  74                         data_size += va_arg(ap, int);
  75                         break;
  76                 case 'b':
  77                         b = va_arg(ap, uint8 *);
  78                         head_size += va_arg(ap, int);
  79                         break;
  80                 case 'd':
  81                         n = va_arg(ap, int);
  82                         head_size += 4;
  83                         break;
  84                 case 'C':
  85                         s = va_arg(ap, char *);
  86                         head_size += str_charnum(s) + 1;
  87                         break;
  88                 }
  89         }
  90         va_end(ap);
  91
  92         /* allocate the space, then scan the format
  93          * again to fill in the values */
  94
  95         *blob = data_blob(NULL, head_size + data_size);
  96
  97         head_ofs = 0;
  98         data_ofs = head_size;
  99
 100         va_start(ap, format);
 101         for (i=0; format[i]; i++) {
 102                 switch (format[i]) {
 103                 case 'U':
 104                         s = va_arg(ap, char *);
 105                         n = str_charnum(s);
 106                         SSVAL(blob->data, head_ofs, n*2); head_ofs += 2;
 107                         SSVAL(blob->data, head_ofs, n*2); head_ofs += 2;
 108                         SIVAL(blob->data, head_ofs, data_ofs); head_ofs += 4;
 109                         push_string(NULL, blob->data+data_ofs,
 110                                         s, n*2, STR_UNICODE|STR_NOALIGN);
 111                         data_ofs += n*2;
 112                         break;
 113                 case 'A':
 114                         s = va_arg(ap, char *);
 115                         n = str_ascii_charnum(s);
 116                         SSVAL(blob->data, head_ofs, n); head_ofs += 2;
 117                         SSVAL(blob->data, head_ofs, n); head_ofs += 2;
 118                         SIVAL(blob->data, head_ofs, data_ofs); head_ofs += 4;
 119                         push_string(NULL, blob->data+data_ofs,
 120                                         s, n, STR_ASCII|STR_NOALIGN);
 121                         data_ofs += n;
 122                         break;
 123                 case 'a':
 124                         n = va_arg(ap, int);
 125                         SSVAL(blob->data, data_ofs, n); data_ofs += 2;
 126                         s = va_arg(ap, char *);
 127                         n = str_charnum(s);
 128                         SSVAL(blob->data, data_ofs, n*2); data_ofs += 2;
 129                         if (0 < n) {
 130                                 push_string(NULL, blob->data+data_ofs, s, n*2,
 131                                             STR_UNICODE|STR_NOALIGN);
 132                         }
 133                         data_ofs += n*2;
 134                         break;
 135
 136                 case 'B':
 137                         b = va_arg(ap, uint8 *);
 138                         n = va_arg(ap, int);
 139                         SSVAL(blob->data, head_ofs, n); head_ofs += 2;
 140                         SSVAL(blob->data, head_ofs, n); head_ofs += 2;
 141                         SIVAL(blob->data, head_ofs, data_ofs); head_ofs += 4;
 142                         if (n && b) /* don't follow null pointers... */
 143                                 memcpy(blob->data+data_ofs, b, n);
 144                         data_ofs += n;
 145                         break;
 146                 case 'd':
 147                         n = va_arg(ap, int);
 148                         SIVAL(blob->data, head_ofs, n); head_ofs += 4;
 149                         break;
 150                 case 'b':
 151                         b = va_arg(ap, uint8 *);
 152                         n = va_arg(ap, int);
 153                         memcpy(blob->data + head_ofs, b, n);
 154                         head_ofs += n;
 155                         break;
 156                 case 'C':
 157                         s = va_arg(ap, char *);
 158                         n = str_charnum(s) + 1;
 159                         head_ofs += push_string(NULL, blob->data+head_ofs, s, n,
 160                                                 STR_ASCII|STR_TERMINATE);
 161                         break;
 162                 }
 163         }
 164         va_end(ap);
 165
 166         return true;
 167 }
 168
 169
 170 /* a helpful macro to avoid running over the end of our blob */
 171 #define NEED_DATA(amount) \
 172 if ((head_ofs + amount) > blob->length) { \
 173         return False; \
 174 }
 175
 176 /*
 177   this is a tiny msrpc packet parser. This the the partner of msrpc_gen
 178
 179   format specifiers are:
 180
 181   U = unicode string (output is unix string)
 182   A = ascii string
 183   B = data blob
 184   b = data blob in header
 185   d = word (4 bytes)
 186   C = constant ascii string
 187  */
 188
 189 bool msrpc_parse(const DATA_BLOB *blob,
 190                  const char *format, ...)
 191 {
 192         int i;
 193         va_list ap;
 194         char **ps, *s;
 195         DATA_BLOB *b;
 196         size_t head_ofs = 0;
 197         uint16 len1, len2;
 198         uint32 ptr;
 199         uint32 *v;
 200
 201         va_start(ap, format);
 202         for (i=0; format[i]; i++) {
 203                 switch (format[i]) {
 204                 case 'U':
 205                         NEED_DATA(8);
 206                         len1 = SVAL(blob->data, head_ofs); head_ofs += 2;
 207                         len2 = SVAL(blob->data, head_ofs); head_ofs += 2;
 208                         ptr =  IVAL(blob->data, head_ofs); head_ofs += 4;
 209
 210                         ps = va_arg(ap, char **);
 211                         if (len1 == 0 && len2 == 0) {
 212                                 *ps = smb_xstrdup("");
 213                         } else {
 214                                 /* make sure its in the right format
 215                                  * be strict */
 216                                 if ((len1 != len2) || (ptr + len1 < ptr) ||
 217                                                 (ptr + len1 < len1) ||
 218                                                 (ptr + len1 > blob->length)) {
 219                                         return false;
 220                                 }
 221                                 if (len1 & 1) {
 222                                         /* if odd length and unicode */
 223                                         return false;
 224                                 }
 225                                 if (blob->data + ptr <
 226                                                 (uint8 *)(unsigned long)ptr ||
 227                                                 blob->data + ptr < blob->data)
 228                                         return false;
 229
 230                                 if (0 < len1) {
 231                                         char *p = NULL;
 232                                         pull_string_talloc(talloc_tos(),
 233                                                 NULL,
 234                                                 0,
 235                                                 &p,
 236                                                 blob->data + ptr,
 237                                                 len1,
 238                                                 STR_UNICODE|STR_NOALIGN);
 239                                         if (p) {
 240                                                 (*ps) = smb_xstrdup(p);
 241                                                 TALLOC_FREE(p);
 242                                         } else {
 243                                                 (*ps) = smb_xstrdup("");
 244                                         }
 245                                 } else {
 246                                         (*ps) = smb_xstrdup("");
 247                                 }
 248                         }
 249                         break;
 250                 case 'A':
 251                         NEED_DATA(8);
 252                         len1 = SVAL(blob->data, head_ofs); head_ofs += 2;
 253                         len2 = SVAL(blob->data, head_ofs); head_ofs += 2;
 254                         ptr =  IVAL(blob->data, head_ofs); head_ofs += 4;
 255
 256                         ps = va_arg(ap, char **);
 257                         /* make sure its in the right format - be strict */
 258                         if (len1 == 0 && len2 == 0) {
 259                                 *ps = smb_xstrdup("");
 260                         } else {
 261                                 if ((len1 != len2) || (ptr + len1 < ptr) ||
 262                                                 (ptr + len1 < len1) ||
 263                                                 (ptr + len1 > blob->length)) {
 264                                         return false;
 265                                 }
 266
 267                                 if (blob->data + ptr <
 268                                                 (uint8 *)(unsigned long)ptr ||
 269                                                 blob->data + ptr < blob->data)
 270                                         return false;
 271
 272                                 if (0 < len1) {
 273                                         char *p = NULL;
 274                                         pull_string_talloc(talloc_tos(),
 275                                                 NULL,
 276                                                 0,
 277                                                 &p,
 278                                                 blob->data + ptr,
 279                                                 len1,
 280                                                 STR_ASCII|STR_NOALIGN);
 281                                         if (p) {
 282                                                 (*ps) = smb_xstrdup(p);
 283                                                 TALLOC_FREE(p);
 284                                         } else {
 285                                                 (*ps) = smb_xstrdup("");
 286                                         }
 287                                 } else {
 288                                         (*ps) = smb_xstrdup("");
 289                                 }
 290                         }
 291                         break;
 292                 case 'B':
 293                         NEED_DATA(8);
 294                         len1 = SVAL(blob->data, head_ofs); head_ofs += 2;
 295                         len2 = SVAL(blob->data, head_ofs); head_ofs += 2;
 296                         ptr =  IVAL(blob->data, head_ofs); head_ofs += 4;
 297
 298                         b = (DATA_BLOB *)va_arg(ap, void *);
 299                         if (len1 == 0 && len2 == 0) {
 300                                 *b = data_blob_null;
 301                         } else {
 302                                 /* make sure its in the right format
 303                                  * be strict */
 304                                 if ((len1 != len2) || (ptr + len1 < ptr) ||
 305                                                 (ptr + len1 < len1) ||
 306                                                 (ptr + len1 > blob->length)) {
 307                                         return false;
 308                                 }
 309
 310                                 if (blob->data + ptr <
 311                                                 (uint8 *)(unsigned long)ptr ||
 312                                                 blob->data + ptr < blob->data)
 313                                         return false;
 314
 315                                 *b = data_blob(blob->data + ptr, len1);
 316                         }
 317                         break;
 318                 case 'b':
 319                         b = (DATA_BLOB *)va_arg(ap, void *);
 320                         len1 = va_arg(ap, unsigned);
 321                         /* make sure its in the right format - be strict */
 322                         NEED_DATA(len1);
 323                         if (blob->data + head_ofs < (uint8 *)head_ofs ||
 324                                         blob->data + head_ofs < blob->data) {
 325                                 return false;
 326                         }
 327
 328                         *b = data_blob(blob->data + head_ofs, len1);
 329                         head_ofs += len1;
 330                         break;
 331                 case 'd':
 332                         v = va_arg(ap, uint32 *);
 333                         NEED_DATA(4);
 334                         *v = IVAL(blob->data, head_ofs); head_ofs += 4;
 335                         break;
 336                 case 'C':
 337                         s = va_arg(ap, char *);
 338
 339                         if (blob->data + head_ofs < (uint8 *)head_ofs ||
 340                                         blob->data + head_ofs < blob->data) {
 341                                 return false;
 342                         }
 343
 344                         {
 345                                 char *p = NULL;
 346                                 size_t ret = pull_string_talloc(talloc_tos(),
 347                                                 NULL,
 348                                                 0,
 349                                                 &p,
 350                                                 blob->data+head_ofs,
 351                                                 blob->length - head_ofs,
 352                                                 STR_ASCII|STR_TERMINATE);
 353                                 if (ret == (size_t)-1 || p == NULL) {
 354                                         return false;
 355                                 }
 356                                 head_ofs += ret;
 357                                 if (strcmp(s, p) != 0) {
 358                                         TALLOC_FREE(p);
 359                                         return false;
 360                                 }
 361                                 TALLOC_FREE(p);
 362                         }
 363                         break;
 364                 }
 365         }
 366         va_end(ap);
 367
 368         return True;
 369 }