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/*
Unix SMB/CIFS implementation.
SMB2 Create Context Blob handling
Copyright (C) Andrew Tridgell 2005
Copyright (C) Stefan Metzmacher 2008-2009
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
#include "../libcli/smb/smb_common.h"
static size_t smb2_create_blob_padding(uint32_t offset, size_t n)
{
if ((offset & (n-1)) == 0) return 0;
return n - (offset & (n-1));
}
/*
parse a set of SMB2 create blobs
*/
NTSTATUS smb2_create_blob_parse(TALLOC_CTX *mem_ctx, const DATA_BLOB buffer,
struct smb2_create_blobs *blobs)
{
const uint8_t *data = buffer.data;
uint32_t remaining = buffer.length;
while (remaining > 0) {
uint32_t next;
uint32_t name_offset, name_length;
uint32_t data_offset;
uint32_t data_length;
char *tag;
DATA_BLOB b;
NTSTATUS status;
if (remaining < 16) {
return NT_STATUS_INVALID_PARAMETER;
}
next = IVAL(data, 0);
name_offset = SVAL(data, 4);
name_length = SVAL(data, 6);
#if 0
reserved = SVAL(data, 8);
#endif
data_offset = SVAL(data, 10);
data_length = IVAL(data, 12);
if ((next & 0x7) != 0 ||
next > remaining ||
name_offset != 16 ||
name_length < 4 ||
name_offset + name_length > remaining ||
(data_offset & 0x7) != 0 ||
(data_offset && (data_offset < name_offset + name_length)) ||
(data_offset > remaining) ||
(data_offset + (uint64_t)data_length > remaining)) {
return NT_STATUS_INVALID_PARAMETER;
}
tag = talloc_strndup(mem_ctx, (const char *)data + name_offset, name_length);
if (tag == NULL) {
return NT_STATUS_NO_MEMORY;
}
b = data_blob_const(data+data_offset, data_length);
status = smb2_create_blob_add(mem_ctx, blobs, tag, b);
if (!NT_STATUS_IS_OK(status)) {
return status;
}
talloc_free(tag);
if (next == 0) break;
remaining -= next;
data += next;
if (remaining < 16) {
return NT_STATUS_INVALID_PARAMETER;
}
}
return NT_STATUS_OK;
}
/*
add a blob to a smb2_create attribute blob
*/
static NTSTATUS smb2_create_blob_push_one(TALLOC_CTX *mem_ctx, DATA_BLOB *buffer,
const struct smb2_create_blob *blob,
bool last)
{
uint32_t ofs = buffer->length;
size_t tag_length = strlen(blob->tag);
size_t blob_offset = 0;
size_t blob_pad = 0;
size_t next_offset = 0;
size_t next_pad = 0;
bool ok;
blob_offset = 0x10 + tag_length;
blob_pad = smb2_create_blob_padding(blob_offset, 8);
next_offset = blob_offset + blob_pad + blob->data.length;
if (!last) {
next_pad = smb2_create_blob_padding(next_offset, 8);
}
ok = data_blob_realloc(mem_ctx, buffer,
buffer->length + next_offset + next_pad);
if (!ok) {
return NT_STATUS_NO_MEMORY;
}
if (last) {
SIVAL(buffer->data, ofs+0x00, 0);
} else {
SIVAL(buffer->data, ofs+0x00, next_offset + next_pad);
}
SSVAL(buffer->data, ofs+0x04, 0x10); /* offset of tag */
SIVAL(buffer->data, ofs+0x06, tag_length); /* tag length */
SSVAL(buffer->data, ofs+0x0A, blob_offset + blob_pad); /* offset of data */
SIVAL(buffer->data, ofs+0x0C, blob->data.length);
memcpy(buffer->data+ofs+0x10, blob->tag, tag_length);
if (blob_pad > 0) {
memset(buffer->data+ofs+blob_offset, 0, blob_pad);
blob_offset += blob_pad;
}
memcpy(buffer->data+ofs+blob_offset, blob->data.data, blob->data.length);
if (next_pad > 0) {
memset(buffer->data+ofs+next_offset, 0, next_pad);
}
return NT_STATUS_OK;
}
/*
create a buffer of a set of create blobs
*/
NTSTATUS smb2_create_blob_push(TALLOC_CTX *mem_ctx, DATA_BLOB *buffer,
const struct smb2_create_blobs blobs)
{
uint32_t i;
NTSTATUS status;
*buffer = (DATA_BLOB) { 0 };
for (i=0; i < blobs.num_blobs; i++) {
bool last = false;
const struct smb2_create_blob *c;
if ((i + 1) == blobs.num_blobs) {
last = true;
}
c = &blobs.blobs[i];
status = smb2_create_blob_push_one(mem_ctx, buffer, c, last);
if (!NT_STATUS_IS_OK(status)) {
return status;
}
}
return NT_STATUS_OK;
}
NTSTATUS smb2_create_blob_add(TALLOC_CTX *mem_ctx, struct smb2_create_blobs *b,
const char *tag, DATA_BLOB data)
{
struct smb2_create_blob *array;
array = talloc_realloc(mem_ctx, b->blobs,
struct smb2_create_blob,
b->num_blobs + 1);
NT_STATUS_HAVE_NO_MEMORY(array);
b->blobs = array;
b->blobs[b->num_blobs].tag = talloc_strdup(b->blobs, tag);
NT_STATUS_HAVE_NO_MEMORY(b->blobs[b->num_blobs].tag);
if (data.data) {
b->blobs[b->num_blobs].data = data_blob_talloc(b->blobs,
data.data,
data.length);
NT_STATUS_HAVE_NO_MEMORY(b->blobs[b->num_blobs].data.data);
} else {
b->blobs[b->num_blobs].data = data_blob_null;
}
b->num_blobs += 1;
return NT_STATUS_OK;
}
/*
* return the first blob with the given tag
*/
struct smb2_create_blob *smb2_create_blob_find(const struct smb2_create_blobs *b,
const char *tag)
{
uint32_t i;
if (b == NULL) {
return NULL;
}
for (i=0; i < b->num_blobs; i++) {
if (strcmp(b->blobs[i].tag, tag) == 0) {
return &b->blobs[i];
}
}
return NULL;
}
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