libcli/smb/smb2_create_blob.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    SMB2 Create Context Blob handling
   5
   6    Copyright (C) Andrew Tridgell 2005
   7    Copyright (C) Stefan Metzmacher 2008-2009
   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 "../libcli/smb/smb_common.h"
  25
  26 static size_t smb2_create_blob_padding(uint32_t offset, size_t n)
  27 {
  28         if ((offset & (n-1)) == 0) return 0;
  29         return n - (offset & (n-1));
  30 }
  31
  32 /*
  33   parse a set of SMB2 create blobs
  34 */
  35 NTSTATUS smb2_create_blob_parse(TALLOC_CTX *mem_ctx, const DATA_BLOB buffer,
  36                                 struct smb2_create_blobs *blobs)
  37 {
  38         const uint8_t *data = buffer.data;
  39         uint32_t remaining = buffer.length;
  40
  41         while (remaining > 0) {
  42                 uint32_t next;
  43                 uint32_t name_offset, name_length;
  44                 uint32_t data_offset;
  45                 uint32_t data_length;
  46                 char *tag;
  47                 DATA_BLOB b;
  48                 NTSTATUS status;
  49
  50                 if (remaining < 16) {
  51                         return NT_STATUS_INVALID_PARAMETER;
  52                 }
  53                 next        = IVAL(data, 0);
  54                 name_offset = SVAL(data, 4);
  55                 name_length = SVAL(data, 6);
  56 #if 0
  57                 reserved    = SVAL(data, 8);
  58 #endif
  59                 data_offset = SVAL(data, 10);
  60                 data_length = IVAL(data, 12);
  61
  62                 if ((next & 0x7) != 0 ||
  63                     next > remaining ||
  64                     name_offset != 16 ||
  65                     name_length < 4 ||
  66                     name_offset + name_length > remaining ||
  67                     (data_offset & 0x7) != 0 ||
  68                     (data_offset && (data_offset < name_offset + name_length)) ||
  69                     (data_offset && (data_offset > remaining)) ||
  70                     (data_offset && data_length &&
  71                                 (data_offset + (uint64_t)data_length > remaining))) {
  72                         return NT_STATUS_INVALID_PARAMETER;
  73                 }
  74
  75                 tag = talloc_strndup(mem_ctx, (const char *)data + name_offset, name_length);
  76                 if (tag == NULL) {
  77                         return NT_STATUS_NO_MEMORY;
  78                 }
  79
  80                 b = data_blob_const(data+data_offset, data_length);
  81                 status = smb2_create_blob_add(mem_ctx, blobs, tag, b);
  82                 if (!NT_STATUS_IS_OK(status)) {
  83                         return status;
  84                 }
  85
  86                 talloc_free(tag);
  87
  88                 if (next == 0) break;
  89
  90                 remaining -= next;
  91                 data += next;
  92
  93                 if (remaining < 16) {
  94                         return NT_STATUS_INVALID_PARAMETER;
  95                 }
  96         }
  97
  98         return NT_STATUS_OK;
  99 }
 100
 101
 102 /*
 103   add a blob to a smb2_create attribute blob
 104 */
 105 static NTSTATUS smb2_create_blob_push_one(TALLOC_CTX *mem_ctx, DATA_BLOB *buffer,
 106                                           const struct smb2_create_blob *blob,
 107                                           bool last)
 108 {
 109         uint32_t ofs = buffer->length;
 110         size_t tag_length = strlen(blob->tag);
 111         size_t blob_offset = 0;
 112         size_t blob_pad = 0;
 113         size_t next_offset = 0;
 114         size_t next_pad = 0;
 115         bool ok;
 116
 117         blob_offset = 0x14 + tag_length;
 118         blob_pad = smb2_create_blob_padding(blob_offset, 8);
 119         next_offset = blob_offset + blob_pad + blob->data.length;
 120         if (!last) {
 121                 next_pad = smb2_create_blob_padding(next_offset, 8);
 122         }
 123
 124         ok = data_blob_realloc(mem_ctx, buffer,
 125                                buffer->length + next_offset + next_pad);
 126         if (!ok) {
 127                 return NT_STATUS_NO_MEMORY;
 128         }
 129
 130         if (last) {
 131                 SIVAL(buffer->data, ofs+0x00, 0);
 132         } else {
 133                 SIVAL(buffer->data, ofs+0x00, next_offset + next_pad);
 134         }
 135         SSVAL(buffer->data, ofs+0x04, 0x10); /* offset of tag */
 136         SIVAL(buffer->data, ofs+0x06, tag_length); /* tag length */
 137         SSVAL(buffer->data, ofs+0x0A, blob_offset + blob_pad); /* offset of data */
 138         SIVAL(buffer->data, ofs+0x0C, blob->data.length);
 139         memcpy(buffer->data+ofs+0x10, blob->tag, tag_length);
 140         if (blob_pad > 0) {
 141                 memset(buffer->data+ofs+blob_offset, 0, blob_pad);
 142                 blob_offset += blob_pad;
 143         }
 144         memcpy(buffer->data+ofs+blob_offset, blob->data.data, blob->data.length);
 145         if (next_pad > 0) {
 146                 memset(buffer->data+ofs+next_offset, 0, next_pad);
 147                 next_offset += next_pad;
 148         }
 149
 150         return NT_STATUS_OK;
 151 }
 152
 153
 154 /*
 155   create a buffer of a set of create blobs
 156 */
 157 NTSTATUS smb2_create_blob_push(TALLOC_CTX *mem_ctx, DATA_BLOB *buffer,
 158                                const struct smb2_create_blobs blobs)
 159 {
 160         int i;
 161         NTSTATUS status;
 162
 163         *buffer = data_blob(NULL, 0);
 164         for (i=0; i < blobs.num_blobs; i++) {
 165                 bool last = false;
 166                 const struct smb2_create_blob *c;
 167
 168                 if ((i + 1) == blobs.num_blobs) {
 169                         last = true;
 170                 }
 171
 172                 c = &blobs.blobs[i];
 173                 status = smb2_create_blob_push_one(mem_ctx, buffer, c, last);
 174                 if (!NT_STATUS_IS_OK(status)) {
 175                         return status;
 176                 }
 177         }
 178         return NT_STATUS_OK;
 179 }
 180
 181
 182 NTSTATUS smb2_create_blob_add(TALLOC_CTX *mem_ctx, struct smb2_create_blobs *b,
 183                               const char *tag, DATA_BLOB data)
 184 {
 185         struct smb2_create_blob *array;
 186
 187         array = talloc_realloc(mem_ctx, b->blobs,
 188                                struct smb2_create_blob,
 189                                b->num_blobs + 1);
 190         NT_STATUS_HAVE_NO_MEMORY(array);
 191         b->blobs = array;
 192
 193         b->blobs[b->num_blobs].tag = talloc_strdup(b->blobs, tag);
 194         NT_STATUS_HAVE_NO_MEMORY(b->blobs[b->num_blobs].tag);
 195
 196         if (data.data) {
 197                 b->blobs[b->num_blobs].data = data_blob_talloc(b->blobs,
 198                                                                data.data,
 199                                                                data.length);
 200                 NT_STATUS_HAVE_NO_MEMORY(b->blobs[b->num_blobs].data.data);
 201         } else {
 202                 b->blobs[b->num_blobs].data = data_blob_null;
 203         }
 204
 205         b->num_blobs += 1;
 206
 207         return NT_STATUS_OK;
 208 }
 209
 210 /*
 211  * return the first blob with the given tag
 212  */
 213 struct smb2_create_blob *smb2_create_blob_find(const struct smb2_create_blobs *b,
 214                                                const char *tag)
 215 {
 216         uint32_t i;
 217
 218         for (i=0; i < b->num_blobs; i++) {
 219                 if (strcmp(b->blobs[i].tag, tag) == 0) {
 220                         return &b->blobs[i];
 221                 }
 222         }
 223
 224         return NULL;
 225 }