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dnsjit/include/dnsjit/core/object/dns.c
Daniel Baumann c3fdfe782f
Merging upstream version 1.2.3. 
Signed-off-by: Daniel Baumann <daniel@debian.org>
2025-02-09 08:33:37 +01:00

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/*
* Copyright (c) 2018-2022, OARC, Inc.
* All rights reserved.
*
* This file is part of dnsjit.
*
* dnsjit 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.
*
* dnsjit 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 dnsjit. If not, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include "core/object/dns.h"
#include "core/object/payload.h"
#include "core/assert.h"
#include <stdlib.h>
#include <string.h>
#ifdef HAVE_ENDIAN_H
#include <endian.h>
#else
#ifdef HAVE_SYS_ENDIAN_H
#include <sys/endian.h>
#else
#ifdef HAVE_MACHINE_ENDIAN_H
#include <machine/endian.h>
#endif
#endif
#endif
#ifdef HAVE_BYTESWAP_H
#include <byteswap.h>
#endif
#ifndef bswap_16
#ifndef bswap16
#define bswap_16(x) swap16(x)
#define bswap_32(x) swap32(x)
#define bswap_64(x) swap64(x)
#else
#define bswap_16(x) bswap16(x)
#define bswap_32(x) bswap32(x)
#define bswap_64(x) bswap64(x)
#endif
#endif
#define _ERR_MALFORMED -2
#define _ERR_NEEDLABELS -3
static core_log_t _log = LOG_T_INIT("core.object.dns");
static core_object_dns_t _defaults = CORE_OBJECT_DNS_INIT(0);
static core_object_dns_label_t _defaults_label = { 0 };
static core_object_dns_rr_t _defaults_rr = { 0 };
static core_object_dns_q_t _defaults_q = { 0 };
core_log_t* core_object_dns_log()
{
return &_log;
}
core_object_dns_t* core_object_dns_new()
{
core_object_dns_t* self;
mlfatal_oom(self = malloc(sizeof(core_object_dns_t)));
*self = _defaults;
return self;
}
core_object_dns_t* core_object_dns_copy(const core_object_dns_t* self)
{
core_object_dns_t* copy;
mlassert_self();
mlfatal_oom(copy = malloc(sizeof(core_object_dns_t)));
memcpy(copy, self, sizeof(core_object_dns_t));
copy->obj_prev = 0;
return (core_object_dns_t*)copy;
}
void core_object_dns_free(core_object_dns_t* self)
{
mlassert_self();
free(self);
}
#define need8(v, p, l) \
if (l < 1) { \
break; \
} \
v = *p; \
p += 1; \
l -= 1
static inline uint16_t _need16(const void* ptr)
{
uint16_t v;
memcpy(&v, ptr, sizeof(v));
return be16toh(v);
}
#define need16(v, p, l) \
if (l < 2) { \
break; \
} \
v = _need16(p); \
p += 2; \
l -= 2
static inline uint32_t _need32(const void* ptr)
{
uint32_t v;
memcpy(&v, ptr, sizeof(v));
return be32toh(v);
}
#define need32(v, p, l) \
if (l < 4) { \
break; \
} \
v = _need32(p); \
p += 4; \
l -= 4
#define needxb(b, x, p, l) \
if (l < x) { \
break; \
} \
memcpy(b, p, x); \
p += x; \
l -= x
#define advancexb(x, p, l) \
if (l < x) { \
break; \
} \
p += x; \
l -= x
int core_object_dns_parse_header(core_object_dns_t* self)
{
const core_object_payload_t* payload;
uint8_t byte;
mlassert_self();
if (!(payload = (core_object_payload_t*)self->obj_prev) || payload->obj_type != CORE_OBJECT_PAYLOAD) {
mlfatal("no obj_prev or invalid type");
}
if (!payload->payload || !payload->len) {
mlfatal("no payload set or zero length");
}
self->payload = self->at = payload->payload;
self->len = self->left = payload->len;
for (;;) {
if (self->includes_dnslen) {
need16(self->dnslen, self->at, self->left);
self->have_dnslen = 1;
}
need16(self->id, self->at, self->left);
self->have_id = 1;
need8(byte, self->at, self->left);
self->qr = byte & (1 << 7) ? 1 : 0;
self->opcode = (byte >> 3) & 0xf;
self->aa = byte & (1 << 2) ? 1 : 0;
self->tc = byte & (1 << 1) ? 1 : 0;
self->rd = byte & (1 << 0) ? 1 : 0;
self->have_qr = self->have_opcode = self->have_aa = self->have_tc = self->have_rd = 1;
need8(byte, self->at, self->left);
self->ra = byte & (1 << 7) ? 1 : 0;
self->z = byte & (1 << 6) ? 1 : 0;
self->ad = byte & (1 << 5) ? 1 : 0;
self->cd = byte & (1 << 4) ? 1 : 0;
self->rcode = byte & 0xf;
self->have_ra = self->have_z = self->have_ad = self->have_cd = self->have_rcode = 1;
need16(self->qdcount, self->at, self->left);
self->have_qdcount = 1;
need16(self->ancount, self->at, self->left);
self->have_ancount = 1;
need16(self->nscount, self->at, self->left);
self->have_nscount = 1;
need16(self->arcount, self->at, self->left);
self->have_arcount = 1;
return 0;
}
// TODO: error here on malformed/truncated? could be quite spammy
return _ERR_MALFORMED;
}
static inline size_t _rdata_labels(uint16_t type)
{
switch (type) {
case CORE_OBJECT_DNS_TYPE_NS:
case CORE_OBJECT_DNS_TYPE_MD:
case CORE_OBJECT_DNS_TYPE_MF:
case CORE_OBJECT_DNS_TYPE_CNAME:
case CORE_OBJECT_DNS_TYPE_MB:
case CORE_OBJECT_DNS_TYPE_MG:
case CORE_OBJECT_DNS_TYPE_MR:
case CORE_OBJECT_DNS_TYPE_PTR:
case CORE_OBJECT_DNS_TYPE_NXT:
case CORE_OBJECT_DNS_TYPE_DNAME:
case CORE_OBJECT_DNS_TYPE_NSEC:
case CORE_OBJECT_DNS_TYPE_TKEY:
case CORE_OBJECT_DNS_TYPE_TSIG:
return 1;
case CORE_OBJECT_DNS_TYPE_SOA:
case CORE_OBJECT_DNS_TYPE_MINFO:
case CORE_OBJECT_DNS_TYPE_RP:
case CORE_OBJECT_DNS_TYPE_TALINK:
return 2;
case CORE_OBJECT_DNS_TYPE_MX:
case CORE_OBJECT_DNS_TYPE_AFSDB:
case CORE_OBJECT_DNS_TYPE_RT:
case CORE_OBJECT_DNS_TYPE_KX:
case CORE_OBJECT_DNS_TYPE_LP:
return 1;
case CORE_OBJECT_DNS_TYPE_PX:
return 2;
case CORE_OBJECT_DNS_TYPE_SIG:
case CORE_OBJECT_DNS_TYPE_RRSIG:
return 1;
case CORE_OBJECT_DNS_TYPE_SRV:
return 1;
case CORE_OBJECT_DNS_TYPE_NAPTR:
return 1;
case CORE_OBJECT_DNS_TYPE_HIP:
return 1;
default:
break;
}
return 0;
}
static inline size_t _label(core_object_dns_t* self, core_object_dns_label_t* label, size_t labels)
{
size_t n;
for (n = 0; self->left && n < labels; n++) {
core_object_dns_label_t* l = &label[n];
*l = _defaults_label;
need8(l->length, self->at, self->left);
if ((l->length & 0xc0) == 0xc0) {
need8(l->offset, self->at, self->left);
l->offset |= (l->length & 0x3f) << 8;
l->have_offset = 1;
return n;
} else if (l->length & 0xc0) {
l->extension_bits = l->length >> 6;
l->have_extension_bits = 1;
return n;
} else if (l->length) {
l->have_length = 1;
l->offset = self->at - self->payload - 1;
advancexb(l->length, self->at, self->left);
l->have_dn = 1;
} else {
l->is_end = 1;
return n;
}
}
return n;
}
int core_object_dns_parse_q(core_object_dns_t* self, core_object_dns_q_t* q, core_object_dns_label_t* label, size_t labels)
{
mlassert_self();
mlassert(q, "q is nil");
mlassert(label, "label is nil");
mlassert(labels, "labels is zero");
mlassert(self->at, "at is nil");
for (;;) {
*q = _defaults_q;
q->labels = _label(self, label, labels);
if (q->labels < labels) {
core_object_dns_label_t* l = &label[q->labels];
if (!(l->have_offset | l->have_extension_bits | l->is_end)) {
// TODO: error here on malformed/truncated? could be quite spammy
return _ERR_MALFORMED;
}
} else {
mlwarning("need more labels, aborting DNS parsing");
return _ERR_NEEDLABELS;
}
q->labels++;
need16(q->type, self->at, self->left);
q->have_type = 1;
need16(q->class, self->at, self->left);
q->have_class = 1;
return 0;
}
// TODO: error here on malformed/truncated? could be quite spammy
return _ERR_MALFORMED;
}
int core_object_dns_parse_rr(core_object_dns_t* self, core_object_dns_rr_t* rr, core_object_dns_label_t* label, size_t labels)
{
size_t rdata_label_sets;
mlassert_self();
mlassert(rr, "rr is nil");
mlassert(label, "label is nil");
mlassert(labels, "labels is zero");
mlassert(self->at, "at is nil");
for (;;) {
*rr = _defaults_rr;
rr->labels = _label(self, label, labels);
if (rr->labels < labels) {
core_object_dns_label_t* l = &label[rr->labels];
if (!(l->have_offset | l->have_extension_bits | l->is_end)) {
// TODO: error here on malformed/truncated? could be quite spammy
return _ERR_MALFORMED;
}
} else {
mlwarning("need more labels, aborting DNS parsing");
return _ERR_NEEDLABELS;
}
rr->labels++;
need16(rr->type, self->at, self->left);
rr->have_type = 1;
need16(rr->class, self->at, self->left);
rr->have_class = 1;
need32(rr->ttl, self->at, self->left);
rr->have_ttl = 1;
need16(rr->rdlength, self->at, self->left);
rr->have_rdlength = 1;
rr->rdata_offset = self->at - self->payload;
if (!(rdata_label_sets = _rdata_labels(rr->type))) {
advancexb(rr->rdlength, self->at, self->left);
rr->have_rdata = 1;
return 0;
}
switch (rr->type) {
case CORE_OBJECT_DNS_TYPE_MX:
case CORE_OBJECT_DNS_TYPE_AFSDB:
case CORE_OBJECT_DNS_TYPE_RT:
case CORE_OBJECT_DNS_TYPE_KX:
case CORE_OBJECT_DNS_TYPE_LP:
case CORE_OBJECT_DNS_TYPE_PX:
advancexb(2, self->at, self->left);
break;
case CORE_OBJECT_DNS_TYPE_SIG:
case CORE_OBJECT_DNS_TYPE_RRSIG:
advancexb(18, self->at, self->left);
break;
case CORE_OBJECT_DNS_TYPE_SRV:
advancexb(6, self->at, self->left);
break;
case CORE_OBJECT_DNS_TYPE_NAPTR: {
uint8_t naptr_length;
advancexb(4, self->at, self->left);
need8(naptr_length, self->at, self->left);
advancexb(naptr_length, self->at, self->left);
need8(naptr_length, self->at, self->left);
advancexb(naptr_length, self->at, self->left);
need8(naptr_length, self->at, self->left);
advancexb(naptr_length, self->at, self->left);
} break;
case CORE_OBJECT_DNS_TYPE_HIP: {
uint8_t hit_length;
uint16_t pk_length;
need8(hit_length, self->at, self->left);
advancexb(1, self->at, self->left);
need16(pk_length, self->at, self->left);
advancexb(hit_length, self->at, self->left);
advancexb(pk_length, self->at, self->left);
if (self->at - self->payload >= rr->rdata_offset + rr->rdlength) {
rdata_label_sets = 0;
}
} break;
}
while (rdata_label_sets) {
rr->rdata_labels += _label(self, &label[rr->labels + rr->rdata_labels], labels - rr->labels - rr->rdata_labels);
if (rr->labels + rr->rdata_labels < labels) {
core_object_dns_label_t* l = &label[rr->labels + rr->rdata_labels];
if (!(l->have_offset | l->have_extension_bits | l->is_end)) {
// TODO: error here on malformed/truncated? could be quite spammy
return _ERR_MALFORMED;
}
} else {
mlwarning("need more labels, aborting DNS parsing");
return _ERR_NEEDLABELS;
}
rr->rdata_labels++;
if (rr->type == CORE_OBJECT_DNS_TYPE_HIP && self->at - self->payload < rr->rdata_offset + rr->rdlength) {
continue;
}
rdata_label_sets--;
}
if (self->at - self->payload < rr->rdata_offset + rr->rdlength) {
rr->padding_offset = self->at - self->payload;
rr->padding_length = rr->rdlength - (rr->padding_offset - rr->rdata_offset);
advancexb(rr->padding_length, self->at, self->left);
/*
* TODO:
*
* This can indicate padding but we do not set that we have padding
* yet because we need to fully understand all record types before
* that and process valid data after the labels
*
rr->have_padding = 1;
*/
} else if (self->at - self->payload > rr->rdata_offset + rr->rdlength) {
// TODO: error here on malformed/truncated? could be quite spammy
return _ERR_MALFORMED;
}
rr->have_rdata = 1;
return 0;
}
// TODO: error here on malformed/truncated? could be quite spammy
return _ERR_MALFORMED;
}
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