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_offset > remaining ||
  64                     name_length != 4 || /* windows enforces this */
  65                     name_offset + name_length > remaining ||
  66                     (data_offset && (data_offset < name_offset + name_length)) ||
  67                     (data_offset && (data_offset > remaining)) ||
  68                     (data_offset && data_length &&
  69                                 (data_offset + (uint64_t)data_length > remaining))) {
  70                         return NT_STATUS_INVALID_PARAMETER;
  71                 }
  72
  73                 tag = talloc_strndup(mem_ctx, (const char *)data + name_offset, name_length);
  74                 if (tag == NULL) {
  75                         return NT_STATUS_NO_MEMORY;
  76                 }
  77
  78                 b = data_blob_const(data+data_offset, data_length);
  79                 status = smb2_create_blob_add(mem_ctx, blobs, tag, b);
  80                 if (!NT_STATUS_IS_OK(status)) {
  81                         return status;
  82                 }
  83
  84                 talloc_free(tag);
  85
  86                 if (next == 0) break;
  87
  88                 remaining -= next;
  89                 data += next;
  90
  91                 if (remaining < 16) {
  92                         return NT_STATUS_INVALID_PARAMETER;
  93                 }
  94         }
  95
  96         return NT_STATUS_OK;
  97 }
  98
  99
 100 /*
 101   add a blob to a smb2_create attribute blob
 102 */
 103 static NTSTATUS smb2_create_blob_push_one(TALLOC_CTX *mem_ctx, DATA_BLOB *buffer,
 104                                           const struct smb2_create_blob *blob,
 105                                           bool last)
 106 {
 107         uint32_t ofs = buffer->length;
 108         size_t tag_length = strlen(blob->tag);
 109         uint8_t pad = smb2_create_blob_padding(blob->data.length+tag_length, 4);
 110
 111         if (!data_blob_realloc(mem_ctx, buffer,
 112                                buffer->length + 0x14 + tag_length + blob->data.length + pad))
 113                 return NT_STATUS_NO_MEMORY;
 114
 115         if (last) {
 116                 SIVAL(buffer->data, ofs+0x00, 0);
 117         } else {
 118                 SIVAL(buffer->data, ofs+0x00, 0x14 + tag_length + blob->data.length + pad);
 119         }
 120         SSVAL(buffer->data, ofs+0x04, 0x10); /* offset of tag */
 121         SIVAL(buffer->data, ofs+0x06, tag_length); /* tag length */
 122         SSVAL(buffer->data, ofs+0x0A, 0x14 + tag_length); /* offset of data */
 123         SIVAL(buffer->data, ofs+0x0C, blob->data.length);
 124         memcpy(buffer->data+ofs+0x10, blob->tag, tag_length);
 125         SIVAL(buffer->data, ofs+0x10+tag_length, 0); /* pad? */
 126         memcpy(buffer->data+ofs+0x14+tag_length, blob->data.data, blob->data.length);
 127         memset(buffer->data+ofs+0x14+tag_length+blob->data.length, 0, pad);
 128
 129         return NT_STATUS_OK;
 130 }
 131
 132
 133 /*
 134   create a buffer of a set of create blobs
 135 */
 136 NTSTATUS smb2_create_blob_push(TALLOC_CTX *mem_ctx, DATA_BLOB *buffer,
 137                                const struct smb2_create_blobs blobs)
 138 {
 139         int i;
 140         NTSTATUS status;
 141
 142         *buffer = data_blob(NULL, 0);
 143         for (i=0; i < blobs.num_blobs; i++) {
 144                 bool last = false;
 145                 const struct smb2_create_blob *c;
 146
 147                 if ((i + 1) == blobs.num_blobs) {
 148                         last = true;
 149                 }
 150
 151                 c = &blobs.blobs[i];
 152                 status = smb2_create_blob_push_one(mem_ctx, buffer, c, last);
 153                 if (!NT_STATUS_IS_OK(status)) {
 154                         return status;
 155                 }
 156         }
 157         return NT_STATUS_OK;
 158 }
 159
 160
 161 NTSTATUS smb2_create_blob_add(TALLOC_CTX *mem_ctx, struct smb2_create_blobs *b,
 162                               const char *tag, DATA_BLOB data)
 163 {
 164         struct smb2_create_blob *array;
 165
 166         array = talloc_realloc(mem_ctx, b->blobs,
 167                                struct smb2_create_blob,
 168                                b->num_blobs + 1);
 169         NT_STATUS_HAVE_NO_MEMORY(array);
 170         b->blobs = array;
 171
 172         b->blobs[b->num_blobs].tag = talloc_strdup(b->blobs, tag);
 173         NT_STATUS_HAVE_NO_MEMORY(b->blobs[b->num_blobs].tag);
 174
 175         if (data.data) {
 176                 b->blobs[b->num_blobs].data = data_blob_talloc(b->blobs,
 177                                                                data.data,
 178                                                                data.length);
 179                 NT_STATUS_HAVE_NO_MEMORY(b->blobs[b->num_blobs].data.data);
 180         } else {
 181                 b->blobs[b->num_blobs].data = data_blob(NULL, 0);
 182         }
 183
 184         b->num_blobs += 1;
 185
 186         return NT_STATUS_OK;
 187 }
 188
 189 /*
 190  * return the first blob with the given tag
 191  */
 192 struct smb2_create_blob *smb2_create_blob_find(const struct smb2_create_blobs *b,
 193                                                const char *tag)
 194 {
 195         uint32_t i;
 196
 197         for (i=0; i < b->num_blobs; i++) {
 198                 if (strcmp(b->blobs[i].tag, tag) == 0) {
 199                         return &b->blobs[i];
 200                 }
 201         }
 202
 203         return NULL;
 204 }