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