diff options
Diffstat (limited to 'include/dnsjit/core/object/dns.c')
| -rw-r--r-- | include/dnsjit/core/object/dns.c | 471 |
1 files changed, 471 insertions, 0 deletions
diff --git a/include/dnsjit/core/object/dns.c b/include/dnsjit/core/object/dns.c new file mode 100644 index 0000000..49aec6d --- /dev/null +++ b/include/dnsjit/core/object/dns.c @@ -0,0 +1,471 @@ +/* + * Copyright (c) 2018-2021, 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; +} |