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/*
Unix SMB/CIFS implementation.
manipulate dns name structures
Copyright (C) 2010 Kai Blin <kai@samba.org>
Heavily based on nbtname.c which is:
Copyright (C) Andrew Tridgell 2005
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/>.
*/
/*
see rfc1002 for the detailed format of compressed names
*/
#include "includes.h"
#include "librpc/gen_ndr/ndr_dns.h"
#include "librpc/gen_ndr/ndr_misc.h"
#include "librpc/gen_ndr/ndr_dnsp.h"
#include "system/locale.h"
#include "lib/util/util_net.h"
#include "ndr_dns_utils.h"
/* don't allow an unlimited number of name components */
#define MAX_COMPONENTS 128
/**
print a dns string
*/
_PUBLIC_ void ndr_print_dns_string(struct ndr_print *ndr,
const char *name,
const char *s)
{
ndr_print_string(ndr, name, s);
}
/*
pull one component of a dns_string
*/
static enum ndr_err_code ndr_pull_component(struct ndr_pull *ndr,
uint8_t **component,
uint32_t *offset,
uint32_t *max_offset)
{
uint8_t len;
unsigned int loops = 0;
while (loops < 5) {
if (*offset >= ndr->data_size) {
return ndr_pull_error(ndr, NDR_ERR_STRING,
"BAD DNS NAME component, bad offset");
}
len = ndr->data[*offset];
if (len == 0) {
*offset += 1;
*max_offset = MAX(*max_offset, *offset);
*component = NULL;
return NDR_ERR_SUCCESS;
}
if ((len & 0xC0) == 0xC0) {
/* its a label pointer */
if (1 + *offset >= ndr->data_size) {
return ndr_pull_error(ndr, NDR_ERR_STRING,
"BAD DNS NAME component, " \
"bad label offset");
}
*max_offset = MAX(*max_offset, *offset + 2);
*offset = ((len&0x3F)<<8) | ndr->data[1 + *offset];
*max_offset = MAX(*max_offset, *offset);
loops++;
continue;
}
if ((len & 0xC0) != 0) {
/* its a reserved length field */
return ndr_pull_error(ndr, NDR_ERR_STRING,
"BAD DNS NAME component, " \
"reserved length field: 0x%02x",
(len &0xC));
}
if (*offset + len + 1 > ndr->data_size) {
return ndr_pull_error(ndr, NDR_ERR_STRING,
"BAD DNS NAME component, "\
"length too long");
}
*component = (uint8_t*)talloc_strndup(ndr,
(const char *)&ndr->data[1 + *offset], len);
NDR_ERR_HAVE_NO_MEMORY(*component);
*offset += len + 1;
*max_offset = MAX(*max_offset, *offset);
return NDR_ERR_SUCCESS;
}
/* too many pointers */
return ndr_pull_error(ndr, NDR_ERR_STRING,
"BAD DNS NAME component, too many pointers");
}
/**
pull a dns_string from the wire
*/
_PUBLIC_ enum ndr_err_code ndr_pull_dns_string(struct ndr_pull *ndr,
int ndr_flags,
const char **s)
{
uint32_t offset = ndr->offset;
uint32_t max_offset = offset;
unsigned num_components;
char *name;
if (!(ndr_flags & NDR_SCALARS)) {
return NDR_ERR_SUCCESS;
}
name = talloc_strdup(ndr->current_mem_ctx, "");
/* break up name into a list of components */
for (num_components=0; num_components<MAX_COMPONENTS;
num_components++) {
uint8_t *component = NULL;
NDR_CHECK(ndr_pull_component(ndr, &component, &offset,
&max_offset));
if (component == NULL) break;
if (num_components > 0) {
name = talloc_asprintf_append_buffer(name, ".%s",
component);
} else {
name = talloc_asprintf_append_buffer(name, "%s",
component);
}
NDR_ERR_HAVE_NO_MEMORY(name);
}
if (num_components == MAX_COMPONENTS) {
return ndr_pull_error(ndr, NDR_ERR_STRING,
"BAD DNS NAME too many components");
}
(*s) = name;
ndr->offset = max_offset;
return NDR_ERR_SUCCESS;
}
/**
push a dns string to the wire
*/
_PUBLIC_ enum ndr_err_code ndr_push_dns_string(struct ndr_push *ndr,
int ndr_flags,
const char *s)
{
return ndr_push_dns_string_list(ndr,
&ndr->dns_string_list,
ndr_flags,
s,
false);
}
_PUBLIC_ enum ndr_err_code ndr_pull_dns_txt_record(struct ndr_pull *ndr, int ndr_flags, struct dns_txt_record *r)
{
NDR_PULL_CHECK_FLAGS(ndr, ndr_flags);
if (ndr_flags & NDR_SCALARS) {
enum ndr_err_code ndr_err;
uint32_t data_size = ndr->data_size;
uint32_t record_size = 0;
ndr_err = ndr_token_retrieve(&ndr->array_size_list, r,
&record_size);
if (NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
NDR_PULL_NEED_BYTES(ndr, record_size);
ndr->data_size = ndr->offset + record_size;
}
NDR_CHECK(ndr_pull_align(ndr, 1));
NDR_CHECK(ndr_pull_dnsp_string_list(ndr, NDR_SCALARS, &r->txt));
NDR_CHECK(ndr_pull_trailer_align(ndr, 1));
ndr->data_size = data_size;
}
if (ndr_flags & NDR_BUFFERS) {
}
return NDR_ERR_SUCCESS;
}
_PUBLIC_ enum ndr_err_code ndr_push_dns_res_rec(struct ndr_push *ndr,
int ndr_flags,
const struct dns_res_rec *r)
{
uint32_t _flags_save_STRUCT = ndr->flags;
uint32_t _saved_offset1, _saved_offset2;
uint16_t length;
ndr_set_flags(&ndr->flags, LIBNDR_PRINT_ARRAY_HEX |
LIBNDR_FLAG_NOALIGN);
if (ndr_flags & NDR_SCALARS) {
uint32_t _flags_save_name = ndr->flags;
NDR_CHECK(ndr_push_align(ndr, 4));
switch (r->rr_type) {
case DNS_QTYPE_TKEY:
case DNS_QTYPE_TSIG:
ndr_set_flags(&ndr->flags, LIBNDR_FLAG_NO_COMPRESSION);
break;
default:
break;
}
NDR_CHECK(ndr_push_dns_string(ndr, NDR_SCALARS, r->name));
ndr->flags = _flags_save_name;
NDR_CHECK(ndr_push_dns_qtype(ndr, NDR_SCALARS, r->rr_type));
NDR_CHECK(ndr_push_dns_qclass(ndr, NDR_SCALARS, r->rr_class));
NDR_CHECK(ndr_push_uint32(ndr, NDR_SCALARS, r->ttl));
_saved_offset1 = ndr->offset;
NDR_CHECK(ndr_push_uint16(ndr, NDR_SCALARS, 0));
if (r->length > 0) {
uint32_t _saved_offset3;
NDR_CHECK(ndr_push_set_switch_value(ndr, &r->rdata,
r->rr_type));
_saved_offset3 = ndr->offset;
NDR_CHECK(ndr_push_dns_rdata(ndr, NDR_SCALARS,
&r->rdata));
if ((ndr->offset != _saved_offset3) &&
(r->unexpected.length > 0)) {
/*
* ndr_push_dns_rdata pushed a known
* record, but we have something
* unexpected. That's invalid.
*/
return ndr_push_error(ndr,
NDR_ERR_LENGTH,
"Invalid...Unexpected " \
"blob length is too " \
"large");
}
}
if (r->unexpected.length > UINT16_MAX) {
return ndr_push_error(ndr, NDR_ERR_LENGTH,
"Unexpected blob length "\
"is too large");
}
NDR_CHECK(ndr_push_bytes(ndr, r->unexpected.data,
r->unexpected.length));
NDR_CHECK(ndr_push_trailer_align(ndr, 4));
length = ndr->offset - (_saved_offset1 + 2);
_saved_offset2 = ndr->offset;
ndr->offset = _saved_offset1;
NDR_CHECK(ndr_push_uint16(ndr, NDR_SCALARS, length));
ndr->offset = _saved_offset2;
}
if (ndr_flags & NDR_BUFFERS) {
NDR_CHECK(ndr_push_dns_rdata(ndr, NDR_BUFFERS,
&r->rdata));
}
ndr->flags = _flags_save_STRUCT;
return NDR_ERR_SUCCESS;
}
_PUBLIC_ enum ndr_err_code ndr_pull_dns_res_rec(struct ndr_pull *ndr,
int ndr_flags,
struct dns_res_rec *r)
{
uint32_t _flags_save_STRUCT = ndr->flags;
uint32_t _saved_offset1;
uint32_t pad, length;
ndr_set_flags(&ndr->flags, LIBNDR_PRINT_ARRAY_HEX |
LIBNDR_FLAG_NOALIGN);
if (ndr_flags & NDR_SCALARS) {
NDR_CHECK(ndr_pull_align(ndr, 4));
NDR_CHECK(ndr_pull_dns_string(ndr, NDR_SCALARS, &r->name));
NDR_CHECK(ndr_pull_dns_qtype(ndr, NDR_SCALARS, &r->rr_type));
NDR_CHECK(ndr_pull_dns_qclass(ndr, NDR_SCALARS, &r->rr_class));
NDR_CHECK(ndr_pull_uint32(ndr, NDR_SCALARS, &r->ttl));
NDR_CHECK(ndr_pull_uint16(ndr, NDR_SCALARS, &r->length));
_saved_offset1 = ndr->offset;
if (r->length > 0) {
NDR_CHECK(ndr_token_store(ndr, &ndr->array_size_list,
&r->rdata,
r->length));
NDR_CHECK(ndr_pull_set_switch_value(ndr, &r->rdata,
r->rr_type));
NDR_CHECK(ndr_pull_dns_rdata(ndr, NDR_SCALARS,
&r->rdata));
} else {
ZERO_STRUCT(r->rdata);
}
length = ndr->offset - _saved_offset1;
if (length > r->length) {
return ndr_pull_error(ndr, NDR_ERR_LENGTH, "TODO");
}
r->unexpected = data_blob_null;
pad = r->length - length;
if (pad > 0) {
NDR_PULL_NEED_BYTES(ndr, pad);
r->unexpected = data_blob_talloc(ndr->current_mem_ctx,
ndr->data +
ndr->offset,
pad);
if (r->unexpected.data == NULL) {
return ndr_pull_error(ndr,
NDR_ERR_ALLOC,
"Failed to allocate a " \
"data blob");
}
ndr->offset += pad;
}
NDR_CHECK(ndr_pull_trailer_align(ndr, 4));
}
if (ndr_flags & NDR_BUFFERS) {
NDR_CHECK(ndr_pull_dns_rdata(ndr, NDR_BUFFERS, &r->rdata));
}
ndr->flags = _flags_save_STRUCT;
return NDR_ERR_SUCCESS;
}
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