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/*
Unix SMB/CIFS implementation.
Copyright (C) Stefan Metzmacher 2014
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"
#include "libcli/smb/smb2_negotiate_context.h"
static size_t smb2_negotiate_context_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 contexts
*/
NTSTATUS smb2_negotiate_context_parse(TALLOC_CTX *mem_ctx, const DATA_BLOB buffer,
uint16_t expected_count,
struct smb2_negotiate_contexts *contexts)
{
const uint8_t *data = buffer.data;
uint32_t remaining = buffer.length;
uint16_t idx;
for (idx = 0; idx < expected_count; idx++) {
uint16_t data_length;
uint16_t type;
NTSTATUS status;
size_t pad;
uint32_t next_offset;
if (remaining < 8) {
return NT_STATUS_INVALID_PARAMETER;
}
type = SVAL(data, 0x00);
data_length = SVAL(data, 0x02);
#if 0
reserved = IVAL(data, 0x04);
#endif
next_offset = 0x08 + data_length;
if (remaining < next_offset) {
return NT_STATUS_INVALID_PARAMETER;
}
status = smb2_negotiate_context_add(
mem_ctx, contexts, type, data+0x08, data_length);
if (!NT_STATUS_IS_OK(status)) {
return status;
}
if (contexts->num_contexts == expected_count) {
break;
}
remaining -= next_offset;
data += next_offset;
if (remaining == 0) {
break;
}
pad = smb2_negotiate_context_padding(next_offset, 8);
if (remaining < pad) {
return NT_STATUS_INVALID_PARAMETER;
}
remaining -= pad;
data += pad;
}
if (contexts->num_contexts != expected_count) {
return NT_STATUS_INVALID_PARAMETER;
}
return NT_STATUS_OK;
}
/*
add a context to a smb2_negotiate attribute context
*/
static NTSTATUS smb2_negotiate_context_push_one(TALLOC_CTX *mem_ctx, DATA_BLOB *buffer,
const struct smb2_negotiate_context *context,
bool last)
{
uint32_t ofs = buffer->length;
size_t next_offset = 0;
size_t next_pad = 0;
bool ok;
if (context->data.length > UINT16_MAX) {
return NT_STATUS_INVALID_PARAMETER_MIX;
}
next_offset = 0x08 + context->data.length;
if (!last) {
next_pad = smb2_negotiate_context_padding(next_offset, 8);
}
ok = data_blob_realloc(mem_ctx, buffer,
buffer->length + next_offset + next_pad);
if (!ok) {
return NT_STATUS_NO_MEMORY;
}
SSVAL(buffer->data, ofs+0x00, context->type);
SIVAL(buffer->data, ofs+0x02, context->data.length);
SIVAL(buffer->data, ofs+0x04, 0);
memcpy(buffer->data+ofs+0x08, context->data.data, context->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 contexts
*/
NTSTATUS smb2_negotiate_context_push(TALLOC_CTX *mem_ctx, DATA_BLOB *buffer,
const struct smb2_negotiate_contexts contexts)
{
uint32_t i;
NTSTATUS status;
*buffer = data_blob(NULL, 0);
for (i=0; i < contexts.num_contexts; i++) {
bool last = false;
const struct smb2_negotiate_context *c;
if ((i + 1) == contexts.num_contexts) {
last = true;
}
c = &contexts.contexts[i];
status = smb2_negotiate_context_push_one(mem_ctx, buffer, c, last);
if (!NT_STATUS_IS_OK(status)) {
return status;
}
}
return NT_STATUS_OK;
}
NTSTATUS smb2_negotiate_context_add(TALLOC_CTX *mem_ctx,
struct smb2_negotiate_contexts *c,
uint16_t type,
const uint8_t *buf,
size_t buflen)
{
struct smb2_negotiate_context *array;
array = talloc_realloc(mem_ctx, c->contexts,
struct smb2_negotiate_context,
c->num_contexts + 1);
NT_STATUS_HAVE_NO_MEMORY(array);
c->contexts = array;
c->contexts[c->num_contexts].type = type;
if (buf != NULL) {
c->contexts[c->num_contexts].data = data_blob_talloc(
c->contexts, buf, buflen);
NT_STATUS_HAVE_NO_MEMORY(c->contexts[c->num_contexts].data.data);
} else {
c->contexts[c->num_contexts].data = data_blob_null;
}
c->num_contexts += 1;
return NT_STATUS_OK;
}
/*
* return the first blob with the given tag
*/
struct smb2_negotiate_context *smb2_negotiate_context_find(const struct smb2_negotiate_contexts *c,
uint16_t type)
{
uint32_t i;
for (i=0; i < c->num_contexts; i++) {
if (c->contexts[i].type == type) {
return &c->contexts[i];
}
}
return NULL;
}
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