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/*
Unix SMB/CIFS implementation.
Manually parsed structures found in the DCERPC protocol
Copyright (C) Stefan Metzmacher 2014
Copyright (C) Gregor Beck 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 "librpc/gen_ndr/ndr_dcerpc.h"
#include "librpc/gen_ndr/ndr_misc.h"
const uint8_t DCERPC_SEC_VT_MAGIC[] = {0x8a,0xe3,0x13,0x71,0x02,0xf4,0x36,0x71};
_PUBLIC_ enum ndr_err_code ndr_push_dcerpc_sec_vt_count(struct ndr_push *ndr, int ndr_flags, const struct dcerpc_sec_vt_count *r)
{
NDR_PUSH_CHECK_FLAGS(ndr, ndr_flags);
/* nothing */
return NDR_ERR_SUCCESS;
}
_PUBLIC_ enum ndr_err_code ndr_pull_dcerpc_sec_vt_count(struct ndr_pull *ndr, int ndr_flags, struct dcerpc_sec_vt_count *r)
{
uint32_t _saved_ofs = ndr->offset;
NDR_PULL_CHECK_FLAGS(ndr, ndr_flags);
if (!(ndr_flags & NDR_SCALARS)) {
return NDR_ERR_SUCCESS;
}
r->count = 0;
while (true) {
uint16_t command;
uint16_t length;
NDR_CHECK(ndr_pull_uint16(ndr, NDR_SCALARS, &command));
NDR_CHECK(ndr_pull_uint16(ndr, NDR_SCALARS, &length));
NDR_CHECK(ndr_pull_advance(ndr, length));
r->count += 1;
if (command & DCERPC_SEC_VT_COMMAND_END) {
break;
}
}
ndr->offset = _saved_ofs;
return NDR_ERR_SUCCESS;
}
_PUBLIC_ enum ndr_err_code ndr_pop_dcerpc_sec_verification_trailer(
struct ndr_pull *ndr, TALLOC_CTX *mem_ctx,
struct dcerpc_sec_verification_trailer **_r)
{
enum ndr_err_code ndr_err;
uint32_t ofs;
uint32_t min_ofs = 0;
struct dcerpc_sec_verification_trailer *r;
DATA_BLOB sub_blob = data_blob_null;
struct ndr_pull *sub_ndr = NULL;
uint32_t remaining;
*_r = NULL;
r = talloc_zero(mem_ctx, struct dcerpc_sec_verification_trailer);
if (r == NULL) {
return NDR_ERR_ALLOC;
}
if (ndr->data_size < sizeof(DCERPC_SEC_VT_MAGIC)) {
/*
* we return with r->count = 0
*/
*_r = r;
return NDR_ERR_SUCCESS;
}
ofs = ndr->data_size - sizeof(DCERPC_SEC_VT_MAGIC);
/* the magic is 4 byte aligned */
ofs &= ~3;
if (ofs > DCERPC_SEC_VT_MAX_SIZE) {
/*
* We just scan the last 1024 bytes.
*/
min_ofs = ofs - DCERPC_SEC_VT_MAX_SIZE;
} else {
min_ofs = 0;
}
while (true) {
int ret;
ret = memcmp(&ndr->data[ofs],
DCERPC_SEC_VT_MAGIC,
sizeof(DCERPC_SEC_VT_MAGIC));
if (ret == 0) {
sub_blob = data_blob_const(&ndr->data[ofs],
ndr->data_size - ofs);
break;
}
if (ofs <= min_ofs) {
break;
}
ofs -= 4;
}
if (sub_blob.length == 0) {
/*
* we return with r->count = 0
*/
*_r = r;
return NDR_ERR_SUCCESS;
}
sub_ndr = ndr_pull_init_blob(&sub_blob, r);
if (sub_ndr == NULL) {
TALLOC_FREE(r);
return NDR_ERR_ALLOC;
}
ndr_err = ndr_pull_dcerpc_sec_verification_trailer(sub_ndr,
NDR_SCALARS | NDR_BUFFERS,
r);
if (ndr_err == NDR_ERR_ALLOC) {
TALLOC_FREE(r);
return NDR_ERR_ALLOC;
}
if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
goto ignore_error;
}
remaining = sub_ndr->data_size - sub_ndr->offset;
if (remaining > 16) {
/*
* we expect not more than 16 byte of additional
* padding after the verification trailer.
*/
goto ignore_error;
}
/*
* We assume that we got a real verification trailer.
*
* We remove it from the available stub data.
*/
ndr->data_size = ofs;
TALLOC_FREE(sub_ndr);
*_r = r;
return NDR_ERR_SUCCESS;
ignore_error:
TALLOC_FREE(sub_ndr);
/*
* just ignore the error, it's likely
* that the magic we found belongs to
* the stub data.
*
* we return with r->count = 0
*/
ZERO_STRUCTP(r);
*_r = r;
return NDR_ERR_SUCCESS;
}
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