monero/external/unbound/util/data/msgparse.c
Erik de Castro Lopo a85b5759f3 Upgrade unbound library
These files were pulled from the 1.6.3 release tarball.

This new version builds against OpenSSL version 1.1 which will be
the default in the new Debian Stable which is due to be released
RealSoonNow (tm).
2017-06-17 23:04:00 +10:00

1094 lines
32 KiB
C

/*
* util/data/msgparse.c - parse wireformat DNS messages.
*
* Copyright (c) 2007, NLnet Labs. All rights reserved.
*
* This software is open source.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of the NLNET LABS nor the names of its contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* \file
* Routines for message parsing a packet buffer to a descriptive structure.
*/
#include "config.h"
#include "util/data/msgparse.h"
#include "util/data/msgreply.h"
#include "util/data/dname.h"
#include "util/data/packed_rrset.h"
#include "util/storage/lookup3.h"
#include "util/regional.h"
#include "sldns/rrdef.h"
#include "sldns/sbuffer.h"
#include "sldns/parseutil.h"
#include "sldns/wire2str.h"
/** smart comparison of (compressed, valid) dnames from packet */
static int
smart_compare(sldns_buffer* pkt, uint8_t* dnow,
uint8_t* dprfirst, uint8_t* dprlast)
{
if(LABEL_IS_PTR(*dnow)) {
/* ptr points to a previous dname */
uint8_t* p = sldns_buffer_at(pkt, PTR_OFFSET(dnow[0], dnow[1]));
if( p == dprfirst || p == dprlast )
return 0;
/* prev dname is also a ptr, both ptrs are the same. */
if(LABEL_IS_PTR(*dprlast) &&
dprlast[0] == dnow[0] && dprlast[1] == dnow[1])
return 0;
}
return dname_pkt_compare(pkt, dnow, dprlast);
}
/**
* Allocate new rrset in region, fill with data.
*/
static struct rrset_parse*
new_rrset(struct msg_parse* msg, uint8_t* dname, size_t dnamelen,
uint16_t type, uint16_t dclass, hashvalue_type hash,
uint32_t rrset_flags, sldns_pkt_section section,
struct regional* region)
{
struct rrset_parse* p = regional_alloc(region, sizeof(*p));
if(!p) return NULL;
p->rrset_bucket_next = msg->hashtable[hash & (PARSE_TABLE_SIZE-1)];
msg->hashtable[hash & (PARSE_TABLE_SIZE-1)] = p;
p->rrset_all_next = 0;
if(msg->rrset_last)
msg->rrset_last->rrset_all_next = p;
else msg->rrset_first = p;
msg->rrset_last = p;
p->hash = hash;
p->section = section;
p->dname = dname;
p->dname_len = dnamelen;
p->type = type;
p->rrset_class = dclass;
p->flags = rrset_flags;
p->rr_count = 0;
p->size = 0;
p->rr_first = 0;
p->rr_last = 0;
p->rrsig_count = 0;
p->rrsig_first = 0;
p->rrsig_last = 0;
return p;
}
/** See if next rrset is nsec at zone apex */
static int
nsec_at_apex(sldns_buffer* pkt)
{
/* we are at ttl position in packet. */
size_t pos = sldns_buffer_position(pkt);
uint16_t rdatalen;
if(sldns_buffer_remaining(pkt) < 7) /* ttl+len+root */
return 0; /* eek! */
sldns_buffer_skip(pkt, 4); /* ttl */;
rdatalen = sldns_buffer_read_u16(pkt);
if(sldns_buffer_remaining(pkt) < rdatalen) {
sldns_buffer_set_position(pkt, pos);
return 0; /* parse error happens later */
}
/* must validate the nsec next domain name format */
if(pkt_dname_len(pkt) == 0) {
sldns_buffer_set_position(pkt, pos);
return 0; /* parse error */
}
/* see if SOA bit is set. */
if(sldns_buffer_position(pkt) < pos+4+rdatalen) {
/* nsec type bitmap contains items */
uint8_t win, blen, bits;
/* need: windownum, bitmap len, firstbyte */
if(sldns_buffer_position(pkt)+3 > pos+4+rdatalen) {
sldns_buffer_set_position(pkt, pos);
return 0; /* malformed nsec */
}
win = sldns_buffer_read_u8(pkt);
blen = sldns_buffer_read_u8(pkt);
bits = sldns_buffer_read_u8(pkt);
/* 0window always first window. bitlen >=1 or parse
error really. bit 0x2 is SOA. */
if(win == 0 && blen >= 1 && (bits & 0x02)) {
sldns_buffer_set_position(pkt, pos);
return 1;
}
}
sldns_buffer_set_position(pkt, pos);
return 0;
}
/** Calculate rrset flags */
static uint32_t
pkt_rrset_flags(sldns_buffer* pkt, uint16_t type, sldns_pkt_section sec)
{
uint32_t f = 0;
if(type == LDNS_RR_TYPE_NSEC && nsec_at_apex(pkt)) {
f |= PACKED_RRSET_NSEC_AT_APEX;
} else if(type == LDNS_RR_TYPE_SOA && sec == LDNS_SECTION_AUTHORITY) {
f |= PACKED_RRSET_SOA_NEG;
}
return f;
}
hashvalue_type
pkt_hash_rrset(sldns_buffer* pkt, uint8_t* dname, uint16_t type,
uint16_t dclass, uint32_t rrset_flags)
{
/* note this MUST be identical to rrset_key_hash in packed_rrset.c */
/* this routine handles compressed names */
hashvalue_type h = 0xab;
h = dname_pkt_hash(pkt, dname, h);
h = hashlittle(&type, sizeof(type), h); /* host order */
h = hashlittle(&dclass, sizeof(dclass), h); /* netw order */
h = hashlittle(&rrset_flags, sizeof(uint32_t), h);
return h;
}
/** create partial dname hash for rrset hash */
static hashvalue_type
pkt_hash_rrset_first(sldns_buffer* pkt, uint8_t* dname)
{
/* works together with pkt_hash_rrset_rest */
/* note this MUST be identical to rrset_key_hash in packed_rrset.c */
/* this routine handles compressed names */
hashvalue_type h = 0xab;
h = dname_pkt_hash(pkt, dname, h);
return h;
}
/** create a rrset hash from a partial dname hash */
static hashvalue_type
pkt_hash_rrset_rest(hashvalue_type dname_h, uint16_t type, uint16_t dclass,
uint32_t rrset_flags)
{
/* works together with pkt_hash_rrset_first */
/* note this MUST be identical to rrset_key_hash in packed_rrset.c */
hashvalue_type h;
h = hashlittle(&type, sizeof(type), dname_h); /* host order */
h = hashlittle(&dclass, sizeof(dclass), h); /* netw order */
h = hashlittle(&rrset_flags, sizeof(uint32_t), h);
return h;
}
/** compare rrset_parse with data */
static int
rrset_parse_equals(struct rrset_parse* p, sldns_buffer* pkt, hashvalue_type h,
uint32_t rrset_flags, uint8_t* dname, size_t dnamelen,
uint16_t type, uint16_t dclass)
{
if(p->hash == h && p->dname_len == dnamelen && p->type == type &&
p->rrset_class == dclass && p->flags == rrset_flags &&
dname_pkt_compare(pkt, dname, p->dname) == 0)
return 1;
return 0;
}
struct rrset_parse*
msgparse_hashtable_lookup(struct msg_parse* msg, sldns_buffer* pkt,
hashvalue_type h, uint32_t rrset_flags, uint8_t* dname,
size_t dnamelen, uint16_t type, uint16_t dclass)
{
struct rrset_parse* p = msg->hashtable[h & (PARSE_TABLE_SIZE-1)];
while(p) {
if(rrset_parse_equals(p, pkt, h, rrset_flags, dname, dnamelen,
type, dclass))
return p;
p = p->rrset_bucket_next;
}
return NULL;
}
/** return type networkformat that rrsig in packet covers */
static int
pkt_rrsig_covered(sldns_buffer* pkt, uint8_t* here, uint16_t* type)
{
size_t pos = sldns_buffer_position(pkt);
sldns_buffer_set_position(pkt, (size_t)(here-sldns_buffer_begin(pkt)));
/* ttl + len + size of small rrsig(rootlabel, no signature) */
if(sldns_buffer_remaining(pkt) < 4+2+19)
return 0;
sldns_buffer_skip(pkt, 4); /* ttl */
if(sldns_buffer_read_u16(pkt) < 19) /* too short */ {
sldns_buffer_set_position(pkt, pos);
return 0;
}
*type = sldns_buffer_read_u16(pkt);
sldns_buffer_set_position(pkt, pos);
return 1;
}
/** true if covered type equals prevtype */
static int
pkt_rrsig_covered_equals(sldns_buffer* pkt, uint8_t* here, uint16_t type)
{
uint16_t t;
if(pkt_rrsig_covered(pkt, here, &t) && t == type)
return 1;
return 0;
}
void
msgparse_bucket_remove(struct msg_parse* msg, struct rrset_parse* rrset)
{
struct rrset_parse** p;
p = &msg->hashtable[ rrset->hash & (PARSE_TABLE_SIZE-1) ];
while(*p) {
if(*p == rrset) {
*p = rrset->rrset_bucket_next;
return;
}
p = &( (*p)->rrset_bucket_next );
}
}
/** change section of rrset from previous to current section */
static void
change_section(struct msg_parse* msg, struct rrset_parse* rrset,
sldns_pkt_section section)
{
struct rrset_parse *p, *prev;
/* remove from list */
if(section == rrset->section)
return;
p = msg->rrset_first;
prev = 0;
while(p) {
if(p == rrset) {
if(prev) prev->rrset_all_next = p->rrset_all_next;
else msg->rrset_first = p->rrset_all_next;
if(msg->rrset_last == rrset)
msg->rrset_last = prev;
break;
}
prev = p;
p = p->rrset_all_next;
}
/* remove from count */
switch(rrset->section) {
case LDNS_SECTION_ANSWER: msg->an_rrsets--; break;
case LDNS_SECTION_AUTHORITY: msg->ns_rrsets--; break;
case LDNS_SECTION_ADDITIONAL: msg->ar_rrsets--; break;
default: log_assert(0);
}
/* insert at end of list */
rrset->rrset_all_next = 0;
if(msg->rrset_last)
msg->rrset_last->rrset_all_next = rrset;
else msg->rrset_first = rrset;
msg->rrset_last = rrset;
/* up count of new section */
switch(section) {
case LDNS_SECTION_AUTHORITY: msg->ns_rrsets++; break;
case LDNS_SECTION_ADDITIONAL: msg->ar_rrsets++; break;
default: log_assert(0);
}
rrset->section = section;
}
/** see if rrset of type RRSIG contains sig over given type */
static int
rrset_has_sigover(sldns_buffer* pkt, struct rrset_parse* rrset, uint16_t type,
int* hasother)
{
int res = 0;
struct rr_parse* rr = rrset->rr_first;
log_assert( rrset->type == LDNS_RR_TYPE_RRSIG );
while(rr) {
if(pkt_rrsig_covered_equals(pkt, rr->ttl_data, type))
res = 1;
else *hasother = 1;
rr = rr->next;
}
return res;
}
/** move rrsigs from sigset to dataset */
static int
moveover_rrsigs(sldns_buffer* pkt, struct regional* region,
struct rrset_parse* sigset, struct rrset_parse* dataset, int duplicate)
{
struct rr_parse* sig = sigset->rr_first;
struct rr_parse* prev = NULL;
struct rr_parse* insert;
struct rr_parse* nextsig;
while(sig) {
nextsig = sig->next;
if(pkt_rrsig_covered_equals(pkt, sig->ttl_data,
dataset->type)) {
if(duplicate) {
/* new */
insert = (struct rr_parse*)regional_alloc(
region, sizeof(struct rr_parse));
if(!insert) return 0;
insert->outside_packet = 0;
insert->ttl_data = sig->ttl_data;
insert->size = sig->size;
/* prev not used */
} else {
/* remove from sigset */
if(prev) prev->next = sig->next;
else sigset->rr_first = sig->next;
if(sigset->rr_last == sig)
sigset->rr_last = prev;
sigset->rr_count--;
sigset->size -= sig->size;
insert = sig;
/* prev not changed */
}
/* add to dataset */
dataset->rrsig_count++;
insert->next = 0;
if(dataset->rrsig_last)
dataset->rrsig_last->next = insert;
else dataset->rrsig_first = insert;
dataset->rrsig_last = insert;
dataset->size += insert->size;
} else {
prev = sig;
}
sig = nextsig;
}
return 1;
}
/** change an rrsig rrset for use as data rrset */
static struct rrset_parse*
change_rrsig_rrset(struct rrset_parse* sigset, struct msg_parse* msg,
sldns_buffer* pkt, uint16_t datatype, uint32_t rrset_flags,
int hasother, sldns_pkt_section section, struct regional* region)
{
struct rrset_parse* dataset = sigset;
hashvalue_type hash = pkt_hash_rrset(pkt, sigset->dname, datatype,
sigset->rrset_class, rrset_flags);
log_assert( sigset->type == LDNS_RR_TYPE_RRSIG );
log_assert( datatype != LDNS_RR_TYPE_RRSIG );
if(hasother) {
/* need to make new rrset to hold data type */
dataset = new_rrset(msg, sigset->dname, sigset->dname_len,
datatype, sigset->rrset_class, hash, rrset_flags,
section, region);
if(!dataset)
return NULL;
switch(section) {
case LDNS_SECTION_ANSWER: msg->an_rrsets++; break;
case LDNS_SECTION_AUTHORITY: msg->ns_rrsets++; break;
case LDNS_SECTION_ADDITIONAL: msg->ar_rrsets++; break;
default: log_assert(0);
}
if(!moveover_rrsigs(pkt, region, sigset, dataset,
msg->qtype == LDNS_RR_TYPE_RRSIG ||
(msg->qtype == LDNS_RR_TYPE_ANY &&
section != LDNS_SECTION_ANSWER) ))
return NULL;
return dataset;
}
/* changeover the type of the rrset to data set */
msgparse_bucket_remove(msg, dataset);
/* insert into new hash bucket */
dataset->rrset_bucket_next = msg->hashtable[hash&(PARSE_TABLE_SIZE-1)];
msg->hashtable[hash&(PARSE_TABLE_SIZE-1)] = dataset;
dataset->hash = hash;
/* use section of data item for result */
change_section(msg, dataset, section);
dataset->type = datatype;
dataset->flags = rrset_flags;
dataset->rrsig_count += dataset->rr_count;
dataset->rr_count = 0;
/* move sigs to end of siglist */
if(dataset->rrsig_last)
dataset->rrsig_last->next = dataset->rr_first;
else dataset->rrsig_first = dataset->rr_first;
dataset->rrsig_last = dataset->rr_last;
dataset->rr_first = 0;
dataset->rr_last = 0;
return dataset;
}
/** Find rrset. If equal to previous it is fast. hash if not so.
* @param msg: the message with hash table.
* @param pkt: the packet in wireformat (needed for compression ptrs).
* @param dname: pointer to start of dname (compressed) in packet.
* @param dnamelen: uncompressed wirefmt length of dname.
* @param type: type of current rr.
* @param dclass: class of current rr.
* @param hash: hash value is returned if the rrset could not be found.
* @param rrset_flags: is returned if the rrset could not be found.
* @param prev_dname_first: dname of last seen RR. First seen dname.
* @param prev_dname_last: dname of last seen RR. Last seen dname.
* @param prev_dnamelen: dname len of last seen RR.
* @param prev_type: type of last seen RR.
* @param prev_dclass: class of last seen RR.
* @param rrset_prev: last seen RRset.
* @param section: the current section in the packet.
* @param region: used to allocate temporary parsing data.
* @return 0 on out of memory.
*/
static int
find_rrset(struct msg_parse* msg, sldns_buffer* pkt, uint8_t* dname,
size_t dnamelen, uint16_t type, uint16_t dclass, hashvalue_type* hash,
uint32_t* rrset_flags,
uint8_t** prev_dname_first, uint8_t** prev_dname_last,
size_t* prev_dnamelen, uint16_t* prev_type,
uint16_t* prev_dclass, struct rrset_parse** rrset_prev,
sldns_pkt_section section, struct regional* region)
{
hashvalue_type dname_h = pkt_hash_rrset_first(pkt, dname);
uint16_t covtype;
if(*rrset_prev) {
/* check if equal to previous item */
if(type == *prev_type && dclass == *prev_dclass &&
dnamelen == *prev_dnamelen &&
smart_compare(pkt, dname, *prev_dname_first,
*prev_dname_last) == 0 &&
type != LDNS_RR_TYPE_RRSIG) {
/* same as previous */
*prev_dname_last = dname;
return 1;
}
/* check if rrsig over previous item */
if(type == LDNS_RR_TYPE_RRSIG && dclass == *prev_dclass &&
pkt_rrsig_covered_equals(pkt, sldns_buffer_current(pkt),
*prev_type) &&
smart_compare(pkt, dname, *prev_dname_first,
*prev_dname_last) == 0) {
/* covers previous */
*prev_dname_last = dname;
return 1;
}
}
/* find by hashing and lookup in hashtable */
*rrset_flags = pkt_rrset_flags(pkt, type, section);
/* if rrsig - try to lookup matching data set first */
if(type == LDNS_RR_TYPE_RRSIG && pkt_rrsig_covered(pkt,
sldns_buffer_current(pkt), &covtype)) {
*hash = pkt_hash_rrset_rest(dname_h, covtype, dclass,
*rrset_flags);
*rrset_prev = msgparse_hashtable_lookup(msg, pkt, *hash,
*rrset_flags, dname, dnamelen, covtype, dclass);
if(!*rrset_prev && covtype == LDNS_RR_TYPE_NSEC) {
/* if NSEC try with NSEC apex bit twiddled */
*rrset_flags ^= PACKED_RRSET_NSEC_AT_APEX;
*hash = pkt_hash_rrset_rest(dname_h, covtype, dclass,
*rrset_flags);
*rrset_prev = msgparse_hashtable_lookup(msg, pkt,
*hash, *rrset_flags, dname, dnamelen, covtype,
dclass);
if(!*rrset_prev) /* untwiddle if not found */
*rrset_flags ^= PACKED_RRSET_NSEC_AT_APEX;
}
if(!*rrset_prev && covtype == LDNS_RR_TYPE_SOA) {
/* if SOA try with SOA neg flag twiddled */
*rrset_flags ^= PACKED_RRSET_SOA_NEG;
*hash = pkt_hash_rrset_rest(dname_h, covtype, dclass,
*rrset_flags);
*rrset_prev = msgparse_hashtable_lookup(msg, pkt,
*hash, *rrset_flags, dname, dnamelen, covtype,
dclass);
if(!*rrset_prev) /* untwiddle if not found */
*rrset_flags ^= PACKED_RRSET_SOA_NEG;
}
if(*rrset_prev) {
*prev_dname_first = (*rrset_prev)->dname;
*prev_dname_last = dname;
*prev_dnamelen = dnamelen;
*prev_type = covtype;
*prev_dclass = dclass;
return 1;
}
}
if(type != LDNS_RR_TYPE_RRSIG) {
int hasother = 0;
/* find matching rrsig */
*hash = pkt_hash_rrset_rest(dname_h, LDNS_RR_TYPE_RRSIG,
dclass, 0);
*rrset_prev = msgparse_hashtable_lookup(msg, pkt, *hash,
0, dname, dnamelen, LDNS_RR_TYPE_RRSIG,
dclass);
if(*rrset_prev && rrset_has_sigover(pkt, *rrset_prev, type,
&hasother)) {
/* yes! */
*prev_dname_first = (*rrset_prev)->dname;
*prev_dname_last = dname;
*prev_dnamelen = dnamelen;
*prev_type = type;
*prev_dclass = dclass;
*rrset_prev = change_rrsig_rrset(*rrset_prev, msg,
pkt, type, *rrset_flags, hasother, section,
region);
if(!*rrset_prev) return 0;
return 1;
}
}
*hash = pkt_hash_rrset_rest(dname_h, type, dclass, *rrset_flags);
*rrset_prev = msgparse_hashtable_lookup(msg, pkt, *hash, *rrset_flags,
dname, dnamelen, type, dclass);
if(*rrset_prev)
*prev_dname_first = (*rrset_prev)->dname;
else *prev_dname_first = dname;
*prev_dname_last = dname;
*prev_dnamelen = dnamelen;
*prev_type = type;
*prev_dclass = dclass;
return 1;
}
/**
* Parse query section.
* @param pkt: packet, position at call must be at start of query section.
* at end position is after query section.
* @param msg: store results here.
* @return: 0 if OK, or rcode on error.
*/
static int
parse_query_section(sldns_buffer* pkt, struct msg_parse* msg)
{
if(msg->qdcount == 0)
return 0;
if(msg->qdcount > 1)
return LDNS_RCODE_FORMERR;
log_assert(msg->qdcount == 1);
if(sldns_buffer_remaining(pkt) <= 0)
return LDNS_RCODE_FORMERR;
msg->qname = sldns_buffer_current(pkt);
if((msg->qname_len = pkt_dname_len(pkt)) == 0)
return LDNS_RCODE_FORMERR;
if(sldns_buffer_remaining(pkt) < sizeof(uint16_t)*2)
return LDNS_RCODE_FORMERR;
msg->qtype = sldns_buffer_read_u16(pkt);
msg->qclass = sldns_buffer_read_u16(pkt);
return 0;
}
size_t
get_rdf_size(sldns_rdf_type rdf)
{
switch(rdf) {
case LDNS_RDF_TYPE_CLASS:
case LDNS_RDF_TYPE_ALG:
case LDNS_RDF_TYPE_INT8:
return 1;
break;
case LDNS_RDF_TYPE_INT16:
case LDNS_RDF_TYPE_TYPE:
case LDNS_RDF_TYPE_CERT_ALG:
return 2;
break;
case LDNS_RDF_TYPE_INT32:
case LDNS_RDF_TYPE_TIME:
case LDNS_RDF_TYPE_A:
case LDNS_RDF_TYPE_PERIOD:
return 4;
break;
case LDNS_RDF_TYPE_TSIGTIME:
return 6;
break;
case LDNS_RDF_TYPE_AAAA:
return 16;
break;
default:
log_assert(0); /* add type above */
/* only types that appear before a domain *
* name are needed. rest is simply copied. */
}
return 0;
}
/** calculate the size of one rr */
static int
calc_size(sldns_buffer* pkt, uint16_t type, struct rr_parse* rr)
{
const sldns_rr_descriptor* desc;
uint16_t pkt_len; /* length of rr inside the packet */
rr->size = sizeof(uint16_t); /* the rdatalen */
sldns_buffer_skip(pkt, 4); /* skip ttl */
pkt_len = sldns_buffer_read_u16(pkt);
if(sldns_buffer_remaining(pkt) < pkt_len)
return 0;
desc = sldns_rr_descript(type);
if(pkt_len > 0 && desc && desc->_dname_count > 0) {
int count = (int)desc->_dname_count;
int rdf = 0;
size_t len;
size_t oldpos;
/* skip first part. */
while(pkt_len > 0 && count) {
switch(desc->_wireformat[rdf]) {
case LDNS_RDF_TYPE_DNAME:
/* decompress every domain name */
oldpos = sldns_buffer_position(pkt);
if((len = pkt_dname_len(pkt)) == 0)
return 0; /* malformed dname */
if(sldns_buffer_position(pkt)-oldpos > pkt_len)
return 0; /* dname exceeds rdata */
pkt_len -= sldns_buffer_position(pkt)-oldpos;
rr->size += len;
count--;
len = 0;
break;
case LDNS_RDF_TYPE_STR:
if(pkt_len < 1) {
/* NOTREACHED, due to 'while(>0)' */
return 0; /* len byte exceeds rdata */
}
len = sldns_buffer_current(pkt)[0] + 1;
break;
default:
len = get_rdf_size(desc->_wireformat[rdf]);
}
if(len) {
if(pkt_len < len)
return 0; /* exceeds rdata */
pkt_len -= len;
sldns_buffer_skip(pkt, (ssize_t)len);
rr->size += len;
}
rdf++;
}
}
/* remaining rdata */
rr->size += pkt_len;
sldns_buffer_skip(pkt, (ssize_t)pkt_len);
return 1;
}
/** skip rr ttl and rdata */
static int
skip_ttl_rdata(sldns_buffer* pkt)
{
uint16_t rdatalen;
if(sldns_buffer_remaining(pkt) < 6) /* ttl + rdatalen */
return 0;
sldns_buffer_skip(pkt, 4); /* ttl */
rdatalen = sldns_buffer_read_u16(pkt);
if(sldns_buffer_remaining(pkt) < rdatalen)
return 0;
sldns_buffer_skip(pkt, (ssize_t)rdatalen);
return 1;
}
/** see if RRSIG is a duplicate of another */
static int
sig_is_double(sldns_buffer* pkt, struct rrset_parse* rrset, uint8_t* ttldata)
{
uint16_t rlen, siglen;
size_t pos = sldns_buffer_position(pkt);
struct rr_parse* sig;
if(sldns_buffer_remaining(pkt) < 6)
return 0;
sldns_buffer_skip(pkt, 4); /* ttl */
rlen = sldns_buffer_read_u16(pkt);
if(sldns_buffer_remaining(pkt) < rlen) {
sldns_buffer_set_position(pkt, pos);
return 0;
}
sldns_buffer_set_position(pkt, pos);
sig = rrset->rrsig_first;
while(sig) {
/* check if rdatalen is same */
memmove(&siglen, sig->ttl_data+4, sizeof(siglen));
siglen = ntohs(siglen);
/* checks if data in packet is exactly the same, this means
* also dname in rdata is the same, but rrsig is not allowed
* to have compressed dnames anyway. If it is compressed anyway
* it will lead to duplicate rrs for qtype=RRSIG. (or ANY).
*
* Cannot use sig->size because size of the other one is not
* calculated yet.
*/
if(siglen == rlen) {
if(siglen>0 && memcmp(sig->ttl_data+6, ttldata+6,
siglen) == 0) {
/* same! */
return 1;
}
}
sig = sig->next;
}
return 0;
}
/** Add rr (from packet here) to rrset, skips rr */
static int
add_rr_to_rrset(struct rrset_parse* rrset, sldns_buffer* pkt,
struct msg_parse* msg, struct regional* region,
sldns_pkt_section section, uint16_t type)
{
struct rr_parse* rr;
/* check section of rrset. */
if(rrset->section != section && type != LDNS_RR_TYPE_RRSIG &&
rrset->type != LDNS_RR_TYPE_RRSIG) {
/* silently drop it - we drop the last part, since
* trust in rr data depends on the section it is in.
* the less trustworthy part is discarded.
* also the last part is more likely to be incomplete.
* RFC 2181: must put RRset only once in response. */
/*
verbose(VERB_QUERY, "Packet contains rrset data in "
"multiple sections, dropped last part.");
log_buf(VERB_QUERY, "packet was", pkt);
*/
/* forwards */
if(!skip_ttl_rdata(pkt))
return LDNS_RCODE_FORMERR;
return 0;
}
if( (msg->qtype == LDNS_RR_TYPE_RRSIG ||
msg->qtype == LDNS_RR_TYPE_ANY)
&& sig_is_double(pkt, rrset, sldns_buffer_current(pkt))) {
if(!skip_ttl_rdata(pkt))
return LDNS_RCODE_FORMERR;
return 0;
}
/* create rr */
if(!(rr = (struct rr_parse*)regional_alloc(region, sizeof(*rr))))
return LDNS_RCODE_SERVFAIL;
rr->outside_packet = 0;
rr->ttl_data = sldns_buffer_current(pkt);
rr->next = 0;
if(type == LDNS_RR_TYPE_RRSIG && rrset->type != LDNS_RR_TYPE_RRSIG) {
if(rrset->rrsig_last)
rrset->rrsig_last->next = rr;
else rrset->rrsig_first = rr;
rrset->rrsig_last = rr;
rrset->rrsig_count++;
} else {
if(rrset->rr_last)
rrset->rr_last->next = rr;
else rrset->rr_first = rr;
rrset->rr_last = rr;
rrset->rr_count++;
}
/* calc decompressed size */
if(!calc_size(pkt, type, rr))
return LDNS_RCODE_FORMERR;
rrset->size += rr->size;
return 0;
}
/**
* Parse packet RR section, for answer, authority and additional sections.
* @param pkt: packet, position at call must be at start of section.
* at end position is after section.
* @param msg: store results here.
* @param region: how to alloc results.
* @param section: section enum.
* @param num_rrs: how many rrs are in the section.
* @param num_rrsets: returns number of rrsets in the section.
* @return: 0 if OK, or rcode on error.
*/
static int
parse_section(sldns_buffer* pkt, struct msg_parse* msg,
struct regional* region, sldns_pkt_section section,
uint16_t num_rrs, size_t* num_rrsets)
{
uint16_t i;
uint8_t* dname, *prev_dname_f = NULL, *prev_dname_l = NULL;
size_t dnamelen, prev_dnamelen = 0;
uint16_t type, prev_type = 0;
uint16_t dclass, prev_dclass = 0;
uint32_t rrset_flags = 0;
hashvalue_type hash = 0;
struct rrset_parse* rrset = NULL;
int r;
if(num_rrs == 0)
return 0;
if(sldns_buffer_remaining(pkt) <= 0)
return LDNS_RCODE_FORMERR;
for(i=0; i<num_rrs; i++) {
/* parse this RR. */
dname = sldns_buffer_current(pkt);
if((dnamelen = pkt_dname_len(pkt)) == 0)
return LDNS_RCODE_FORMERR;
if(sldns_buffer_remaining(pkt) < 10) /* type, class, ttl, len */
return LDNS_RCODE_FORMERR;
type = sldns_buffer_read_u16(pkt);
sldns_buffer_read(pkt, &dclass, sizeof(dclass));
if(0) { /* debug show what is being parsed. */
if(type == LDNS_RR_TYPE_RRSIG) {
uint16_t t;
if(pkt_rrsig_covered(pkt,
sldns_buffer_current(pkt), &t))
fprintf(stderr, "parse of %s(%d) [%s(%d)]",
sldns_rr_descript(type)?
sldns_rr_descript(type)->_name: "??",
(int)type,
sldns_rr_descript(t)?
sldns_rr_descript(t)->_name: "??",
(int)t);
} else
fprintf(stderr, "parse of %s(%d)",
sldns_rr_descript(type)?
sldns_rr_descript(type)->_name: "??",
(int)type);
fprintf(stderr, " %s(%d) ",
sldns_lookup_by_id(sldns_rr_classes,
(int)ntohs(dclass))?sldns_lookup_by_id(
sldns_rr_classes, (int)ntohs(dclass))->name:
"??", (int)ntohs(dclass));
dname_print(stderr, pkt, dname);
fprintf(stderr, "\n");
}
/* see if it is part of an existing RR set */
if(!find_rrset(msg, pkt, dname, dnamelen, type, dclass, &hash,
&rrset_flags, &prev_dname_f, &prev_dname_l,
&prev_dnamelen, &prev_type, &prev_dclass, &rrset,
section, region))
return LDNS_RCODE_SERVFAIL;
if(!rrset) {
/* it is a new RR set. hash&flags already calculated.*/
(*num_rrsets)++;
rrset = new_rrset(msg, dname, dnamelen, type, dclass,
hash, rrset_flags, section, region);
if(!rrset)
return LDNS_RCODE_SERVFAIL;
}
else if(0) {
fprintf(stderr, "is part of existing: ");
dname_print(stderr, pkt, rrset->dname);
fprintf(stderr, " type %s(%d)\n",
sldns_rr_descript(rrset->type)?
sldns_rr_descript(rrset->type)->_name: "??",
(int)rrset->type);
}
/* add to rrset. */
if((r=add_rr_to_rrset(rrset, pkt, msg, region, section,
type)) != 0)
return r;
}
return 0;
}
int
parse_packet(sldns_buffer* pkt, struct msg_parse* msg, struct regional* region)
{
int ret;
if(sldns_buffer_remaining(pkt) < LDNS_HEADER_SIZE)
return LDNS_RCODE_FORMERR;
/* read the header */
sldns_buffer_read(pkt, &msg->id, sizeof(uint16_t));
msg->flags = sldns_buffer_read_u16(pkt);
msg->qdcount = sldns_buffer_read_u16(pkt);
msg->ancount = sldns_buffer_read_u16(pkt);
msg->nscount = sldns_buffer_read_u16(pkt);
msg->arcount = sldns_buffer_read_u16(pkt);
if(msg->qdcount > 1)
return LDNS_RCODE_FORMERR;
if((ret = parse_query_section(pkt, msg)) != 0)
return ret;
if((ret = parse_section(pkt, msg, region, LDNS_SECTION_ANSWER,
msg->ancount, &msg->an_rrsets)) != 0)
return ret;
if((ret = parse_section(pkt, msg, region, LDNS_SECTION_AUTHORITY,
msg->nscount, &msg->ns_rrsets)) != 0)
return ret;
if(sldns_buffer_remaining(pkt) == 0 && msg->arcount == 1) {
/* BIND accepts leniently that an EDNS record is missing.
* so, we do too. */
} else if((ret = parse_section(pkt, msg, region,
LDNS_SECTION_ADDITIONAL, msg->arcount, &msg->ar_rrsets)) != 0)
return ret;
/* if(sldns_buffer_remaining(pkt) > 0) { */
/* there is spurious data at end of packet. ignore */
/* } */
msg->rrset_count = msg->an_rrsets + msg->ns_rrsets + msg->ar_rrsets;
return 0;
}
/** parse EDNS options from EDNS wireformat rdata */
static int
parse_edns_options(uint8_t* rdata_ptr, size_t rdata_len,
struct edns_data* edns, struct regional* region)
{
/* while still more options, and have code+len to read */
/* ignores partial content (i.e. rdata len 3) */
while(rdata_len >= 4) {
uint16_t opt_code = sldns_read_uint16(rdata_ptr);
uint16_t opt_len = sldns_read_uint16(rdata_ptr+2);
rdata_ptr += 4;
rdata_len -= 4;
if(opt_len > rdata_len)
break; /* option code partial */
if(!edns_opt_append(edns, region, opt_code, opt_len,
rdata_ptr)) {
log_err("out of memory");
return 0;
}
rdata_ptr += opt_len;
rdata_len -= opt_len;
}
return 1;
}
int
parse_extract_edns(struct msg_parse* msg, struct edns_data* edns,
struct regional* region)
{
struct rrset_parse* rrset = msg->rrset_first;
struct rrset_parse* prev = 0;
struct rrset_parse* found = 0;
struct rrset_parse* found_prev = 0;
size_t rdata_len;
uint8_t* rdata_ptr;
/* since the class encodes the UDP size, we cannot use hash table to
* find the EDNS OPT record. Scan the packet. */
while(rrset) {
if(rrset->type == LDNS_RR_TYPE_OPT) {
/* only one OPT RR allowed. */
if(found) return LDNS_RCODE_FORMERR;
/* found it! */
found_prev = prev;
found = rrset;
}
prev = rrset;
rrset = rrset->rrset_all_next;
}
if(!found) {
memset(edns, 0, sizeof(*edns));
edns->udp_size = 512;
return 0;
}
/* check the found RRset */
/* most lenient check possible. ignore dname, use last opt */
if(found->section != LDNS_SECTION_ADDITIONAL)
return LDNS_RCODE_FORMERR;
if(found->rr_count == 0)
return LDNS_RCODE_FORMERR;
if(0) { /* strict checking of dname and RRcount */
if(found->dname_len != 1 || !found->dname
|| found->dname[0] != 0) return LDNS_RCODE_FORMERR;
if(found->rr_count != 1) return LDNS_RCODE_FORMERR;
}
log_assert(found->rr_first && found->rr_last);
/* remove from packet */
if(found_prev) found_prev->rrset_all_next = found->rrset_all_next;
else msg->rrset_first = found->rrset_all_next;
if(found == msg->rrset_last)
msg->rrset_last = found_prev;
msg->arcount --;
msg->ar_rrsets --;
msg->rrset_count --;
/* take the data ! */
edns->edns_present = 1;
edns->ext_rcode = found->rr_last->ttl_data[0];
edns->edns_version = found->rr_last->ttl_data[1];
edns->bits = sldns_read_uint16(&found->rr_last->ttl_data[2]);
edns->udp_size = ntohs(found->rrset_class);
edns->opt_list = NULL;
/* take the options */
rdata_len = found->rr_first->size;
rdata_ptr = found->rr_first->ttl_data+6;
if(!parse_edns_options(rdata_ptr, rdata_len, edns, region))
return 0;
/* ignore rrsigs */
return 0;
}
int
parse_edns_from_pkt(sldns_buffer* pkt, struct edns_data* edns,
struct regional* region)
{
size_t rdata_len;
uint8_t* rdata_ptr;
log_assert(LDNS_QDCOUNT(sldns_buffer_begin(pkt)) == 1);
log_assert(LDNS_ANCOUNT(sldns_buffer_begin(pkt)) == 0);
log_assert(LDNS_NSCOUNT(sldns_buffer_begin(pkt)) == 0);
/* check edns section is present */
if(LDNS_ARCOUNT(sldns_buffer_begin(pkt)) > 1) {
return LDNS_RCODE_FORMERR;
}
if(LDNS_ARCOUNT(sldns_buffer_begin(pkt)) == 0) {
memset(edns, 0, sizeof(*edns));
edns->udp_size = 512;
return 0;
}
/* domain name must be the root of length 1. */
if(pkt_dname_len(pkt) != 1)
return LDNS_RCODE_FORMERR;
if(sldns_buffer_remaining(pkt) < 10) /* type, class, ttl, rdatalen */
return LDNS_RCODE_FORMERR;
if(sldns_buffer_read_u16(pkt) != LDNS_RR_TYPE_OPT)
return LDNS_RCODE_FORMERR;
edns->edns_present = 1;
edns->udp_size = sldns_buffer_read_u16(pkt); /* class is udp size */
edns->ext_rcode = sldns_buffer_read_u8(pkt); /* ttl used for bits */
edns->edns_version = sldns_buffer_read_u8(pkt);
edns->bits = sldns_buffer_read_u16(pkt);
edns->opt_list = NULL;
/* take the options */
rdata_len = sldns_buffer_read_u16(pkt);
if(sldns_buffer_remaining(pkt) < rdata_len)
return LDNS_RCODE_FORMERR;
rdata_ptr = sldns_buffer_current(pkt);
if(!parse_edns_options(rdata_ptr, rdata_len, edns, region))
return LDNS_RCODE_SERVFAIL;
/* ignore rrsigs */
return 0;
}
void
log_edns_opt_list(enum verbosity_value level, const char* info_str,
struct edns_option* list)
{
if(verbosity >= level && list) {
char str[128], *s;
size_t slen;
verbose(level, "%s", info_str);
while(list) {
s = str;
slen = sizeof(str);
(void)sldns_wire2str_edns_option_print(&s, &slen, list->opt_code,
list->opt_data, list->opt_len);
verbose(level, " %s", str);
list = list->next;
}
}
}