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/*
** Copyright 1998 - 1999 Double Precision, Inc.
** See COPYING for distribution information.
*/
#include "rfc1035.h"
#include <stdlib.h>
#include <string.h>
#include <errno.h>
void rfc1035_replyfree(struct rfc1035_reply *p)
{
struct rfc1035_reply *q;
while (p)
{
q=p->next;
if (p->mallocedbuf) free(p->mallocedbuf);
if (p->qdptr) free(p->qdptr);
if (p->anptr) free(p->anptr);
if (p->nsptr) free(p->nsptr);
if (p->arptr) free(p->arptr);
if (p->allrrs) free(p->allrrs);
free(p);
p=q;
}
}
const char *rfc1035_replyuncompress(const char **ptr,
const struct rfc1035_reply *reply, char *namebuf)
{
unsigned i=0;
unsigned l;
const char *end=reply->reply+reply->replylen;
const char *newptr=0;
int cnt=0;
for (;;)
{
if ( (*ptr) == end) return (0);
l=(unsigned char)*(*ptr)++;
if (l > 63)
{
if ((l & 0xC0) != 0xC0) return (0);
if ( (*ptr) == end) return (0);
l= ((l & 63) << 8) + (unsigned char)*(*ptr)++;
if (l >= reply->replylen) return (0);
ptr= &newptr;
newptr=reply->reply+l;
if ( ++cnt > 100) return (0);
/* Detect loops */
continue;
}
if (l == 0) break;
if (i)
{
if (i >= RFC1035_MAXNAMESIZE) return (0);
if (namebuf) namebuf[i]='.';
++i;
}
if (RFC1035_MAXNAMESIZE-i < l) return (0);
if (namebuf)
memcpy(namebuf+i, *ptr, l);
i += l;
*ptr += l;
}
if (namebuf) namebuf[i]=0;
return (namebuf ? namebuf:"");
}
const char *rfc1035_replyhostname( const struct rfc1035_reply *r, const char *n,
char *namebuf)
{
const char *p=rfc1035_replyuncompress(&n, r, namebuf);
if (!p) strcpy(namebuf, "error");
return (p);
}
static void doparse(struct rfc1035_reply *, struct rfc1035_rr *);
struct rfc1035_reply *rfc1035_replyparse(const char *p, unsigned l)
{
struct rfc1035_reply *r=(struct rfc1035_reply *)
malloc(sizeof(struct rfc1035_reply));
char c;
unsigned n;
int pass;
unsigned *lenptrs[3];
struct rfc1035_rr *rrptrs[3];
const char *end=p+l;
unsigned allcnt;
if (!r) return (0);
r->next=0;
r->reply=p;
r->replylen=l;
r->mallocedbuf=0;
memset(&r->server_addr, 0, sizeof(r->server_addr));
r->qdptr=0;
r->anptr=0;
r->nsptr=0;
r->arptr=0;
r->allrrs=0;
if (l < 12)
{
errno=EINVAL;
rfc1035_replyfree(r);
return (0);
}
c=p[2];
r->rd= c & 1;
c >>= 1;
r->tc= c & 1;
c >>= 1;
r->aa= c & 1;
c >>= 1;
r->opcode= c & 15;
c >>= 4;
r->qr= c & 1;
r->ra=(p[3] >> 7) & 1;
r->rcode=p[3] & 15;
r->qdcount= ((unsigned)(unsigned char)p[4] << 8) | (unsigned char)p[5];
r->ancount= ((unsigned)(unsigned char)p[6] << 8) | (unsigned char)p[7];
r->nscount= ((unsigned)(unsigned char)p[8] << 8) | (unsigned char)p[9];
r->arcount= ((unsigned)(unsigned char)p[10]<< 8) | (unsigned char)p[11];
if (r->qdcount >= l || r->ancount >= l || r->nscount >= l ||
r->arcount >= l ||
(n=r->qdcount + r->ancount) >= l ||
(n += r->nscount) >= l ||
n + r->arcount >= l)
{
errno=EINVAL;
rfc1035_replyfree(r);
return (0);
}
if ((r->qdcount && (r->qdptr=malloc(sizeof(struct rfc1035_query)
* r->qdcount)) == 0) ||
(r->ancount && (r->anptr=malloc(sizeof(struct rfc1035_rr)
* r->ancount)) == 0) ||
(r->nscount && (r->nsptr=malloc(sizeof(struct rfc1035_rr)
* r->nscount)) == 0) ||
(r->arcount && (r->arptr=malloc(sizeof(struct rfc1035_rr)
* r->arcount)) == 0) ||
(r->ancount + r->nscount + r->arcount &&
(r->allrrs=malloc(sizeof(*r->allrrs)*(
r->ancount + r->nscount + r->arcount))) == 0)
)
{
rfc1035_replyfree(r);
return (0);
}
p += 12;
l -= 12;
for (n=0; n<r->qdcount; n++)
{
r->qdptr[n].name=p;
if (rfc1035_replyuncompress( &p, r, 0 ) == 0)
{
errno=EINVAL;
rfc1035_replyfree(r);
return (0);
}
if (p > end-4) return (0);
r->qdptr[n].qtype=((unsigned)(unsigned char)p[0] << 8)
| (unsigned char)p[1];
p += 2;
r->qdptr[n].qclass=((unsigned)(unsigned char)p[0] << 8)
| (unsigned char)p[1];
p += 2;
}
lenptrs[0]= &r->ancount;
lenptrs[1]= &r->nscount;
lenptrs[2]= &r->arcount;
rrptrs[0]= r->anptr;
rrptrs[1]= r->nsptr;
rrptrs[2]= r->arptr;
allcnt=0;
for (pass=0; pass<3; pass++)
{
struct rfc1035_rr *rrp= rrptrs[pass];
for (n=0; n< *lenptrs[pass]; n++)
{
r->allrrs[allcnt++]=rrp;
rrp->rrname=p;
if (rfc1035_replyuncompress( &p, r, 0 )
== 0)
{
errno=EINVAL;
rfc1035_replyfree(r);
return (0);
}
if (p > end-10) return (0);
rrp->rrtype=((unsigned)(unsigned char)p[0] << 8)
| (unsigned char)p[1];
p += 2;
rrp->rrclass=((unsigned)(unsigned char)p[0] << 8)
| (unsigned char)p[1];
p += 2;
rrp->ttl=((RFC1035_UINT32)(unsigned char)p[0] << 24) |
((RFC1035_UINT32)(unsigned char)p[1] << 16) |
((RFC1035_UINT32)(unsigned char)p[2] << 8) |
(unsigned char)p[3];
p += 4;
rrp->rdlength=((unsigned)(unsigned char)p[0] << 8)
| (unsigned char)p[1];
p += 2;
rrp->rdata= rrp->rdlength ? p:0;
if (end - p < rrp->rdlength)
{
errno=EINVAL;
rfc1035_replyfree(r);
return (0);
}
p += rrp->rdlength;
doparse(r, rrp);
++rrp;
}
}
return (r);
}
static void doparse(struct rfc1035_reply *r, struct rfc1035_rr *rr)
{
const char *p;
static const char error[]="\005error";
memset(&rr->rr, '\0', sizeof(rr->rr));
if (rr->rrclass != RFC1035_CLASS_IN) return;
switch (rr->rrtype) {
case RFC1035_TYPE_A:
if (rr->rdlength < 4)
rr->rr.inaddr.s_addr=0;
else
memcpy(&rr->rr.inaddr.s_addr,
rr->rdata, 4);
break;
#if RFC1035_IPV6
case RFC1035_TYPE_AAAA:
memset(&rr->rr.in6addr, 0, sizeof(rr->rr.in6addr));
if (rr->rdlength >= sizeof(struct in6_addr))
memcpy(&rr->rr.in6addr, rr->rdata,
sizeof(rr->rr.in6addr));
break;
#endif
case RFC1035_TYPE_CNAME:
case RFC1035_TYPE_MB:
case RFC1035_TYPE_MG:
case RFC1035_TYPE_MR:
case RFC1035_TYPE_MD:
case RFC1035_TYPE_MF:
case RFC1035_TYPE_NS:
case RFC1035_TYPE_PTR:
rr->rr.domainname=p=rr->rdata;
if (rfc1035_replyuncompress(&p, r, 0) == 0 ||
p > rr->rdata + rr->rdlength)
rr->rr.domainname=error;
break;
case RFC1035_TYPE_SOA:
rr->rr.soa.mname_label=p=rr->rdata;
if (rr->rdlength < 20 ||
rfc1035_replyuncompress(&p, r, 0) == 0 ||
p > rr->rdata + rr->rdlength ||
(rr->rr.soa.rname_label=p, rfc1035_replyuncompress(&p,
r, 0)) == 0 ||
p > rr->rdata + rr->rdlength - 20)
{
rr->rr.soa.mname_label=error;
rr->rr.soa.rname_label=error;
rr->rr.soa.serial=0;
rr->rr.soa.refresh=0;
rr->rr.soa.retry=0;
rr->rr.soa.expire=0;
rr->rr.soa.minimum=0;
}
else
{
rr->rr.soa.serial=
((RFC1035_UINT32)(unsigned char)p[0] << 24) |
((RFC1035_UINT32)(unsigned char)p[1] << 16) |
((RFC1035_UINT32)(unsigned char)p[2] << 8) |
(unsigned char)p[3];
p += 4;
rr->rr.soa.refresh=
((RFC1035_UINT32)(unsigned char)p[0] << 24) |
((RFC1035_UINT32)(unsigned char)p[1] << 16) |
((RFC1035_UINT32)(unsigned char)p[2] << 8) |
(unsigned char)p[3];
p += 4;
rr->rr.soa.retry=
((RFC1035_UINT32)(unsigned char)p[0] << 24) |
((RFC1035_UINT32)(unsigned char)p[1] << 16) |
((RFC1035_UINT32)(unsigned char)p[2] << 8) |
(unsigned char)p[3];
p += 4;
rr->rr.soa.expire=
((RFC1035_UINT32)(unsigned char)p[0] << 24) |
((RFC1035_UINT32)(unsigned char)p[1] << 16) |
((RFC1035_UINT32)(unsigned char)p[2] << 8) |
(unsigned char)p[3];
p += 4;
rr->rr.soa.minimum=
((RFC1035_UINT32)(unsigned char)p[0] << 24) |
((RFC1035_UINT32)(unsigned char)p[1] << 16) |
((RFC1035_UINT32)(unsigned char)p[2] << 8) |
(unsigned char)p[3];
}
break;
case RFC1035_TYPE_MX:
p=rr->rdata;
if (rr->rdlength < 2)
{
rr->rr.mx.preference=0;
rr->rr.mx.mx_label=error;
}
else
{
rr->rr.mx.preference=
((unsigned)(unsigned char)p[0] << 8) |
(unsigned char)p[1];
p += 2;
rr->rr.mx.mx_label=p;
if (rfc1035_replyuncompress(&p, r, 0) == 0
|| p > rr->rdata + rr->rdlength)
{
rr->rr.mx.preference=0;
rr->rr.mx.mx_label=error;
}
}
break;
case RFC1035_TYPE_HINFO:
p=rr->rdata;
rr->rr.hinfo.hinfo_str=error;
rr->rr.hinfo.os_str=error;
if (rr->rdlength && (unsigned char)*p < rr->rdlength)
{
const char *q=p+1+(unsigned char)*p;
if (q < rr->rdata + rr->rdlength &&
q+(unsigned char)*q < rr->rdata + rr->rdlength)
{
rr->rr.hinfo.hinfo_str=p;
rr->rr.hinfo.os_str=q;
}
}
break;
case RFC1035_TYPE_MINFO:
rr->rr.minfo.rmailbx_label=p=rr->rdata;
if (rfc1035_replyuncompress(&p, r, 0) == 0 ||
p > rr->rdata + rr->rdlength ||
(rr->rr.minfo.emailbx_label=p,
rfc1035_replyuncompress(&p, r, 0)) == 0 ||
p > rr->rdata + rr->rdlength)
{
rr->rr.minfo.rmailbx_label=error;
rr->rr.minfo.emailbx_label=error;
}
break;
default:
break;
}
}
/*
** Randomize order of resource records.
*/
static void rr_random(struct rfc1035_rr *p, unsigned n)
{
unsigned i;
for (i=0; i<n; i++)
{
size_t j=rand() % n;
{
struct rfc1035_rr buf=p[j];
p[j]=p[i];
p[i]=buf;
}
}
}
void rfc1035_rr_rand_an(struct rfc1035_reply *rr)
{
rr_random(rr->anptr, rr->ancount);
}
void rfc1035_rr_rand_ns(struct rfc1035_reply *rr)
{
rr_random(rr->nsptr, rr->nscount);
}
void rfc1035_rr_rand_ar(struct rfc1035_reply *rr)
{
rr_random(rr->arptr, rr->arcount);
}
void rfc1035_rr_rand(struct rfc1035_reply *rr)
{
rfc1035_rr_rand_an(rr);
rfc1035_rr_rand_ns(rr);
rfc1035_rr_rand_ar(rr);
}
