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HardenedBSD/usr.sbin/named/ns_validate.c

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NAMED from BIND 4.9.3 BETA9 pl1 (no local changes)
1994-09-22 21:46:15 +02:00
/**************************************************************************
* ns_validate.c (was security.c in original ISI contribution)
* author: anant kumar
* contributed: March 17, 1993
*
* implements validation procedure for RR's received from a server as a
* response to a query.
*/
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/file.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <syslog.h>
#include <errno.h>
#include <stdio.h>
#include <resolv.h>
#include "named.h"
#ifdef VALIDATE
static int isvalid __P((struct namebuf *, int, int, char *, int)),
check_addr_ns __P((struct databuf **,
struct sockaddr_in *,
char *)),
check_in_tables __P((struct databuf **,
struct sockaddr_in *,
char *));
#if 0
static void stick_in_queue __P((char *, int, int, char *));
#endif
static NAMEADDR nameaddrlist[MAXNAMECACHE];
static int firstNA = 0,
lastNA = 0;
static TO_Validate *validateQ, *currentVQ;
static int VQcount;
/*****************************************************************
* validate() is called from dovalidate(). it takes as parameters,
* the domain name sought, the class, type etc. of record, the server
* that gave us the answer and the data it gave us
*
* it returns VALID if it is able to validate the record, INVALID if it cannot.
* furtehr VALID is split into VALID_CACHE if we need to cache this record
* since the domainname is not something we are authoritative for and
* VALID_NO_CACHE if the name is something we are authoritative for.
*
* pseudocode for function validate is as follows:
* validate(domain, server, type, class, data, dlen, rcode) {
*
* if(dname or a higher level name not found in cache)
* return INVALID;
* if (NS records for "domain" found in cache){
*
* if(we are authoritative) /findns() returned NXDOMAIN;/
* if(we did not have an exact match on names)
* =>the name does not exist in our database
* => data is bad: return INVALID
* if(data agrees with what we have)
* return VALID_NO_CACHE;
* else return INVALID;
*
* if(we are not authoritative) /findns() returned OK;/
* if (address records for NS's found in cache){
* if("server" = one of the addresses){
* return VALID_CACHE;
* }else{
* stick in queue of "to_validate" data;
* return (INVALID);
* }
* else return INVALID;
*
* This performs the validation procedure described above. Checks
* for the longest component of the dname that has a NS record
* associated with it. At any stage, if no data is found, it implies
* that the name is bad (has an unknown domain identifier) thus, we
* return INVALID.
* If address of one of these servers matches the address of the server
* that returned us this data, we are happy!
*
* since findns will set needs_prime_cache if np = NULL is passed, we always
* reset it. will let ns_req do it when we are searching for ns records to
* query someone. hence in all the three cases of switch(findns())
* we have needs_prime_cache = 0;
*****************************************************************************/
int
validate(dname, server, type, class, data, dlen
#ifdef NCACHE
,rcode
#endif
)
char *dname;
struct sockaddr_in *server;
int type;
int class;
char *data;
int dlen;
#ifdef NCACHE
int rcode;
#endif
{
struct namebuf *np, *dnamep;
struct hashbuf *htp;
struct databuf *nsp[NSMAX];
int count;
char *fname;
int exactmatch = 0;
struct fwdinfo *fwd;
#ifdef DATUMREFCNT
nsp[0] = NULL;
#endif
dprintf(3, (ddt,
"validate(), d:%s, s:[%s], t:%d, c:%d\n",
dname, inet_ntoa(server->sin_addr), type, class));
/* everything from forwarders is the GOSPEL */
for (fwd = fwdtab; fwd != NULL; fwd = fwd->next) {
if (server->sin_addr.s_addr == fwd->fwdaddr.sin_addr.s_addr)
return(VALID_CACHE);
}
htp = hashtab;
if (priming && (dname[0] == '\0'))
np = NULL;
else
np = nlookup(dname, &htp, &fname, 0);
/* we were able to locate namebufs for this domain, or a parent domain,
* or ??? */
if (np == NULL) {
fname = (char *)malloc(1);
fname[0] = '\0';
}
dprintf(5, (ddt,
"validate:namebuf found np:0x%x, d:\"%s\", f:\"%s\"\n",
np, dname, fname));
/* save the namebuf if we were able to locate the exact dname */
if (!strcasecmp(dname, fname)) {
dnamep = np;
exactmatch = 1;
}
if (np == NULL && fname != NULL) {
free((char *)fname);
}
switch (findns(&np, class, nsp, &count, 0)) {
case NXDOMAIN:
/** we are authoritative for this domain, lookup name
* in our zone data, if it matches, return valid.
* in either case, do not cache
**/
dprintf(5, (ddt, "validate: auth data found\n"));
#ifdef DATUMREFCNT
free_nsp(nsp);
#endif
if (needs_prime_cache)
needs_prime_cache = 0;
#ifdef NCACHE
if(rcode == NXDOMAIN) {
/* If we had an exactmatch on the name, we found the
* name in our authority database, so this couldn't
* have been a bad name. INVALID data, say so
*/
if (exactmatch)
return INVALID;
else
/* we did not have an exactmatch, the data is
* good, we do not NCACHE stuff we are
* authoritative for, though.
*/
return VALID_NO_CACHE;
}
#endif
if (!strcasecmp(dname, np->n_dname)) {
/* if the name we seek is the same as that we have ns
* records for, compare the data we have to see if it
* matches. if it does, return valid_no_cache, if it
* doesn't, invalid.
*/
if (isvalid(np, type, class, data, dlen))
return VALID_NO_CACHE;
else
return INVALID;
}
/* we found ns records in a higher level, if we were unable to
* locate the exact name earlier, it means we are
* authoritative for this domain but do not have records for
* this name. this name is obviously invalid
*/
if (!exactmatch)
return INVALID;
/* we found the exact name earlier and we are obviously
* authoritative so check for data records and see if any
* match.
*/
if (isvalid(dnamep, type, class, data, dlen))
return VALID_NO_CACHE;
else
return INVALID;
case SERVFAIL:/* could not find name server records*/
/* stick_in_queue(dname, type, class, data); */
if (needs_prime_cache)
needs_prime_cache = 0;
#ifdef DATUMREFCNT
free_nsp(nsp);
#endif
return INVALID;
case OK: /*proceed */
dprintf(5,
(ddt,
"validate:found ns records:calling check_addr_ns\n"));
if (needs_prime_cache)
needs_prime_cache = 0;
if (check_addr_ns(nsp, server, dname)) {
#ifdef DATUMREFCNT
free_nsp(nsp);
#endif
return VALID_CACHE;
}
/* server is not one of those we know of */
/* stick_in_queue(dname, type, class, data); */
#ifdef DATUMREFCNT
free_nsp(nsp);
#endif
return INVALID;
default:
#ifdef DATUMREFCNT
free_nsp(nsp);
#endif
return INVALID;
} /*switch*/
} /*validate*/
/***********************************************************************
* validate rr returned by somebody against your own database, if you are
* authoritative for the information. if you have a record that matches,
* return 1, else return 0. validate() above will use this and determine
* if the record should be returned/discarded.
***********************************************************************/
static int
isvalid(np, type, class, data, dlen)
struct namebuf *np;
int type, class;
char *data;
int dlen;
{
register struct databuf *dp;
for (dp = np->n_data; dp != NULL; dp = dp->d_next) {
if (!wanted(dp, class, type)) {
if ((type == T_CNAME) && (class == dp->d_class)) {
/* if a cname exists, any other will not */
return(0);
/* we come here only for zone info,
* so -ve $ed info can't be
*/
}
continue;
}
/* type and class match, if i get here
* let's now compare the data section, per RR type
*/
/* unless, of course, the data was negative, in which case
* we should return FAILURE since we should not have found
* data here.
*/
if ((data == NULL) || (dlen == 0)) {
return 0;
}
/* XXX: why aren't we just calling db_cmp() ?
*/
switch (type) {
char *td;
u_char *tdp;
int x;
case T_A:
case T_WKS:
case T_HINFO:
case T_UINFO:
case T_UID:
case T_GID:
case T_TXT:
case T_X25:
case T_ISDN:
#ifdef ALLOW_T_UNSPEC
case T_UNSPEC:
#endif
x = memcmp(dp->d_data, data, dlen);
dprintf(3, (ddt, "type = %d, GOOD = %d\n",
type, x));
if (x == 0)
return (1);
else
break;
case T_CNAME:
case T_MB:
case T_MG:
case T_MR:
case T_NS:
case T_PTR:
x = strncasecmp((char *)dp->d_data, data, dlen);
dprintf(3, (ddt, "type = %d, GOOD = %d\n",
type, x));
if (x == 0)
return (1);
else
break;
case T_MINFO:
case T_SOA:
case T_RP:
/* compare first string */
x = strncasecmp((char *)dp->d_data, data,
strlen(data) + 1);
if (x != 0)
break;
/* move to second string */
td = data + (strlen(data) + 1);
tdp = dp->d_data +
(strlen((char *)dp->d_data)+1);
/* compare second string */
x = strncasecmp(td, (char *)tdp,
strlen((char *)td+1));
if (x != 0)
break;
/* move beyond second string, to
* set of words in SOA.
* RP and MINFO stuff really
* ends here
*/
td = td + strlen((char *)td) + 1;
tdp = tdp + strlen((char *)tdp) + 1;
if (type == T_SOA) {
x = memcmp(td, (char *)tdp,
5*INT32SZ);
if (x != 0)
break;
}
/* everything was equal, wow!
* so return a success
*/
return (1);
case T_MX:
case T_AFSDB:
case T_RT:
x = memcmp(dp->d_data, data,
INT16SZ);
if (x != 0)
break;
td = data + INT16SZ;
tdp = dp->d_data + INT16SZ;
x = strncasecmp(td, (char *)tdp,
strlen((char *)td) + 1);
if (x != 0)
break;
return (1);
default:
dprintf(3, (ddt, "unknown type %d\n", type));
return (0);
}
/* continue in loop if record did not match */
}
/* saw no record of interest in whole chain
* If the data we were trying to validate was negative, we succeeded!
* else we failed
*/
if ((data == NULL) || (dlen == 0)) {
/* negative data, report success */
return 1;
}
/* positive data, no such RR, validation failed */
return (0);
}
/******************************************************************
* get a list of databufs that have ns addresses for the closest domain
* you know about, get their addresses and confirm that server indeed
* is one of them. if yes return 1 else 0.
* first checks the cache that we build in nslookup() earlier
* when we ns_forw(). if unableto find it there, it checks the entire
* hash table to do address translations.
*******************************************************************/
static int
check_addr_ns(nsp, server, dname)
struct databuf **nsp;
struct sockaddr_in *server;
char *dname;
{
int i, found=0;
char sname[MAXDNAME];
struct in_addr *saddr = &(server->sin_addr);
struct databuf **nsdp;
dprintf(5, (ddt,
"check_addr_ns: s:[%s], db:0x%x, d:\"%s\"\n",
inet_ntoa(*saddr), nsp, dname));
for(i = lastNA; i != firstNA; i = (i+1) % MAXNAMECACHE) {
if (!bcmp((char *)saddr,
(char *)&(nameaddrlist[i].ns_addr),
INADDRSZ)) {
strcpy(sname, nameaddrlist[i].nsname);
found = 1;
break;
}
}
if (found) {
dprintf(3, (ddt,
"check_addr_ns: found address:[%s]\n",
inet_ntoa(*saddr)));
for (nsdp = nsp; *nsdp != NULL;nsdp++) {
dprintf(5, (ddt,
"check_addr_ns:names are:%s, %s\n",
sname,(*nsdp)->d_data));
if (!strcasecmp(sname,(char *)((*nsdp)->d_data))) {
return (1);
}
}
}
/* could not find name in my cache of servers, must go through the
* whole grind
*/
dprintf(2, (ddt, "check_addr_ns:calling check_in_tables()\n"));
return (check_in_tables(nsp, server, dname));
}
/*************************************************************************
* checks in hash tables for the address of servers whose name is in the
* data section of nsp records. borrows code from nslookup()/ns_forw.c
* largely.
*************************************************************************/
static int
check_in_tables(nsp, server, syslogdname)
struct databuf *nsp[];
struct sockaddr_in *server;
char *syslogdname;
{
register struct namebuf *np;
register struct databuf *dp, *nsdp;
struct hashbuf *tmphtp;
char *dname, *fname;
int class;
int qcomp();
dprintf(3, (ddt, "check_in_tables(nsp=x%x,qp=x%x,'%s')\n",
nsp, server, syslogdname));
while ((nsdp = *nsp++) != NULL) {
class = nsdp->d_class;
dname = (char *)nsdp->d_data;
dprintf(3, (ddt, "check_in_tables: NS %s c%d t%d (x%x)\n",
dname, class, nsdp->d_type, nsdp->d_flags));
tmphtp = ((nsdp->d_flags & DB_F_HINT) ? fcachetab : hashtab);
np = nlookup(dname, &tmphtp, &fname, 1);
if (np == NULL || fname != dname) {
dprintf(3, (ddt, "%s: not found %s %x\n",
dname, fname, np));
continue;
}
/* look for name server addresses */
for (dp = np->n_data; dp != NULL; dp = dp->d_next) {
if (stale(dp))
continue;
if (dp->d_type != T_A || dp->d_class != class)
continue;
#ifdef NCACHE
if (dp->d_rcode)
continue;
#endif
if (!bcmp((char *)dp->d_data,
(char *)&(server->sin_addr),
INADDRSZ)) {
return (1);
}
}
}
return (0); /* haven't been able to locate the right address */
}
/************************************************************************
* is called in nslookup() and stores the name vs address of a name server
* --& check_in_tables above--
* we contact, in a list of a maximum MAXNAMECACHE entries. we later refer
* -- NAMEADDR nameaddrlist[MAXNAMECACHE]; --
* to this list when we are trying to resolve the name in check_addr_ns().
*************************************************************************/
void
store_name_addr(servername, serveraddr, syslogdname, sysloginfo)
char *servername;
struct in_addr *serveraddr;
char *syslogdname;
char *sysloginfo;
{
int i;
dprintf(3, (ddt,
"store_name_addr:s:%s, a:[%s]\n",
servername, inet_ntoa(*serveraddr)));
/* if we already have the name address pair in cache, return */
for (i = lastNA; i != firstNA; i = (i+1) % MAXNAMECACHE) {
if (strcasecmp(servername, nameaddrlist[i].nsname) == 0) {
if (serveraddr->s_addr
==
nameaddrlist[i].ns_addr.s_addr) {
dprintf(5, (ddt,
"store_name_addr:found n and a [%s] [%s] in our $\n",
inet_ntoa(nameaddrlist[i].ns_addr),
inet_ntoa(*serveraddr)));
return;
} /* if */
} else if (serveraddr->s_addr
==
nameaddrlist[i].ns_addr.s_addr) {
#ifdef BAD_IDEA
/*
* log this as it needs to be fixed.
* replace old name by new, next query likely to have
* NS record matching new
*/
if (!haveComplained(
(char*)dhash((u_char*)nameaddrlist[i].nsname,
strlen(nameaddrlist[i].nsname)),
(char*)dhash((u_char*)servername,
strlen(servername))
)
) {
syslog(LOG_INFO,
"%s: server name mismatch for [%s]: (%s != %s) (server for %s)",
sysloginfo,
inet_ntoa(*serveraddr),
nameaddrlist[i].nsname, servername,
syslogdname);
}
#endif
free(nameaddrlist[i].nsname);
nameaddrlist[i].nsname =
(char *)malloc((unsigned)strlen(servername)+1);
strcpy(nameaddrlist[i].nsname, servername);
return;
}
}
/* we have to add this one to our cache */
nameaddrlist[firstNA].nsname =
(char *)malloc((unsigned)strlen(servername)+1);
strcpy(nameaddrlist[firstNA].nsname, servername);
bcopy((char *)serveraddr,
(char *)&(nameaddrlist[firstNA].ns_addr),
INADDRSZ);
dprintf(2, (ddt, "store_name_addr:added entry #:%d n:%s a:[%s]\n",
firstNA, nameaddrlist[firstNA].nsname,
inet_ntoa(nameaddrlist[firstNA].ns_addr)));
firstNA = (firstNA+1) % MAXNAMECACHE;
if (firstNA == lastNA) {
free(nameaddrlist[firstNA].nsname);
nameaddrlist[firstNA].nsname = 0;
lastNA = (lastNA+1) % MAXNAMECACHE;
}
return;
}
/*
* Decode the resource record 'rrp' and validate the RR.
* Borrows code almost entirely from doupdate(). is a rather
* non-invasive routine since it just goes thru the same motions
* as doupdate but just marks the array validatelist entry as
* the return code from validate(). This is later used in doupdate
* to cache/not cache the entry. also used in update_msg() to
* delete/keep the record from the outgoing message.
*/
int
dovalidate(msg, msglen, rrp, zone, flags, server, VCode)
u_char *msg, *rrp;
int msglen, zone, flags;
struct sockaddr_in *server;
int *VCode;
{
register u_char *cp;
register int n;
int class, type, dlen, n1;
u_int32_t ttl;
char dname[MAXDNAME];
u_char *cp1;
u_char data[BUFSIZ];
register HEADER *hp = (HEADER *) msg;
dprintf(2, (ddt, "dovalidate(zone %d, flags %x)\n",
zone, flags));
#ifdef DEBUG
if (debug >= 10)
fp_query(msg, ddt);
#endif
cp = rrp;
n = dn_expand(msg, msg + msglen, cp, dname, sizeof dname);
if (n < 0) {
hp->rcode = FORMERR;
return (-1);
}
cp += n;
GETSHORT(type, cp);
GETSHORT(class, cp);
GETLONG(ttl, cp);
GETSHORT(dlen, cp);
dprintf(2, (ddt, "dovalidate: dname %s type %d class %d ttl %d\n",
dname, type, class, ttl));
/*
* Convert the resource record data into the internal
* database format.
*/
switch (type) {
case T_A:
case T_WKS:
case T_HINFO:
case T_UINFO:
case T_UID:
case T_GID:
case T_TXT:
case T_X25:
case T_ISDN:
#ifdef ALLOW_T_UNSPEC
case T_UNSPEC:
#endif
cp1 = cp;
n = dlen;
cp += n;
break;
case T_CNAME:
case T_MB:
case T_MG:
case T_MR:
case T_NS:
case T_PTR:
n = dn_expand(msg, msg + msglen, cp,
(char *)data, sizeof data);
if (n < 0) {
hp->rcode = FORMERR;
return (-1);
}
cp += n;
cp1 = data;
n = strlen((char *)data) + 1;
break;
case T_MINFO:
case T_SOA:
case T_RP:
n = dn_expand(msg, msg + msglen, cp,
(char *)data, sizeof data);
if (n < 0) {
hp->rcode = FORMERR;
return (-1);
}
cp += n;
cp1 = data + (n = strlen((char *)data) + 1);
n1 = sizeof(data) - n;
if (type == T_SOA)
n1 -= 5 * INT32SZ;
n = dn_expand(msg, msg + msglen, cp, (char *)cp1, n1);
if (n < 0) {
hp->rcode = FORMERR;
return (-1);
}
cp += n;
cp1 += strlen((char *)cp1) + 1;
if (type == T_SOA) {
bcopy((char *)cp, (char *)cp1, n = 5 * INT32SZ);
cp += n;
cp1 += n;
}
n = cp1 - data;
cp1 = data;
break;
case T_MX:
case T_AFSDB:
case T_RT:
/* grab preference */
bcopy((char *)cp, data, INT16SZ);
cp1 = data + INT16SZ;
cp += INT16SZ;
/* get name */
n = dn_expand(msg, msg + msglen, cp,
(char *)cp1, sizeof(data) - INT16SZ);
if (n < 0) {
hp->rcode = FORMERR;
return(-1);
}
cp += n;
/* compute end of data */
cp1 += strlen((char *)cp1) + 1;
/* compute size of data */
n = cp1 - data;
cp1 = data;
break;
default:
dprintf(3, (ddt, "unknown type %d\n", type));
return ((cp - rrp) + dlen);
}
if (n > MAXDATA) {
dprintf(2, (ddt,
"update type %d: %d bytes is too much data\n",
type, n));
hp->rcode = NOCHANGE; /* XXX - FORMERR ??? */
return(-1);
}
*VCode = validate(dname, server, type, class,(char *)cp1, n
#ifdef NCACHE
,NOERROR
#endif
);
if (*VCode == INVALID) {
dprintf(2, (ddt,
"validation failed d:%s, t:%d, c:%d\n",
dname, type, class));
} else {
dprintf(2, (ddt,
"validation succeeded d:%s, t:%d, c:%d\n",
dname, type, class));
}
return(cp -rrp);
}
#if 0
/******************************************************************
* This manages a data structure that stores all RRs that we were
* unable to validate. Am not sure exactly what purpose this might
* serve but until such time as we are sure it will not help, let
* me do it anyway.
*****************************************************************/
static void
stick_in_queue(dname, type, class, data)
char *dname;
int type;
int class;
char *data;
{
struct timeval tp;
struct _TIMEZONE tzp;
TO_Validate *tempVQ;
u_long leasttime;
if (validateQ == NULL) {
validateQ = (TO_Validate *)malloc(sizeof(TO_Validate));
validateQ->type = type;
validateQ->class = class;
validateQ->dname = malloc((unsigned)strlen(dname)+1);
strcpy(validateQ->dname, dname);
validateQ->data = malloc((unsigned)strlen(data)+1);
strcpy(validateQ->data, data);
gettimeofday(&tp, &tzp);
validateQ->time = tp.tv_sec;
VQcount = 1;
validateQ->next = validateQ->prev = NULL;
currentVQ = validateQ;
return;
}
if (VQcount < MAXVQ) {
tempVQ =(TO_Validate *)malloc(sizeof(TO_Validate));
tempVQ->type = type;
tempVQ->class = class;
tempVQ->dname = malloc((unsigned)strlen(dname)+1);
strcpy(tempVQ->dname, dname);
tempVQ->data = malloc((unsigned)strlen(data)+1);
strcpy(tempVQ->data, data);
gettimeofday(&tp,&tzp);
tempVQ->time = tp.tv_sec;
tempVQ->next = currentVQ->next;
tempVQ->prev = currentVQ;
if (currentVQ->next != NULL)
currentVQ->next->prev = tempVQ;
currentVQ->next = tempVQ;
currentVQ = tempVQ;
VQcount++;
return;
}
gettimeofday(&tp, &tzp);
leasttime = validateQ->time;
currentVQ = validateQ;
for (tempVQ = validateQ; tempVQ != NULL; tempVQ = tempVQ->next) {
if (tp.tv_sec >= tempVQ->time +VQEXPIRY) {
tempVQ->type = type;
tempVQ->class = class;
strcpy(tempVQ->dname, dname);
strcpy(tempVQ->data, data);
tempVQ->time = tp.tv_sec;
currentVQ = tempVQ;
return;
}
if (tempVQ->time < leasttime) {
leasttime = tempVQ->time;
currentVQ = tempVQ;
}
}
currentVQ->type = type;
currentVQ->class = class;
strcpy(currentVQ->dname, dname);
strcpy(currentVQ->data, data);
currentVQ->time = tp.tv_sec;
return;
}
#endif
/* removes any INVALID RR's from the msg being returned, updates msglen to
* reflect the new message length.
*/
int
update_msg(msg, msglen, Vlist, c)
u_char *msg;
int *msglen;
int Vlist[];
int c;
{
register HEADER *hp;
register u_char *cp;
int i;
int n = 0;
u_char *tempcp, *newcp;
int *RRlen;
int qlen; /* the length of the query section*/
u_int16_t rdlength;
u_int16_t ancount, nscount;
u_int16_t new_ancount, new_nscount, new_arcount;
char dname[MAXDNAME], qname[MAXDNAME];
u_char data[MAXDNAME];
u_char **dpp;
u_char *dnptrs[40];
u_char **edp = dnptrs + sizeof(dnptrs)/sizeof(dnptrs[0]);
u_char *eom = msg + *msglen;
int n_new;
int rembuflen, newlen;
u_char *newmsg;
u_int16_t type, class, dlen;
u_int32_t ttl;
int inv = 0;
#ifdef DEBUG
if (debug) {
fprintf(ddt, "update_msg: msglen:%d, c:%d\n", *msglen, c);
if (debug >= 10)
fp_query(msg, ddt);
}
#endif
/* just making sure we do not do all the work for nothing */
for (i=0; i<c; i++) {
if (Vlist[i] == INVALID) {
inv = 1;
break;
}
}
if (inv != 1) {
/* no invalid records, go about your job */
return (0);
}
dprintf(2, (ddt, "update_msg: NEEDS updating:\n"));
RRlen = (int *)malloc((unsigned)c*sizeof(int));
hp = (HEADER *)msg;
new_ancount = ancount = ntohs(hp->ancount);
new_nscount = nscount = ntohs(hp->nscount);
new_arcount = ntohs(hp->arcount);
cp = msg + HFIXEDSZ;
newlen = HFIXEDSZ;
/* skip the query section */
qlen = dn_expand(msg, eom, cp, qname, sizeof qname);
if (qlen <= 0) {
dprintf(2, (ddt, "dn_skipname() failed, bad record\n"));
goto badend;
}
cp +=qlen;
GETSHORT(type,cp);
GETSHORT(class,cp);
qlen += 2 * INT16SZ;
newlen += qlen;
for (i = 0; i < c; i++) {
if (Vlist[i] == INVALID) {
if (i < ancount)
new_ancount--;
else if (i < ancount+nscount)
new_nscount--;
else
new_arcount--;
}
RRlen[i] = dn_skipname(cp, msg + *msglen);
if (RRlen[i] <= 0) {
dprintf(2, (ddt,
"dn_skipname() failed, bad record\n"));
goto badend;
}
RRlen[i] += 2 * INT16SZ + INT32SZ;
/*type+class+TTL*/
cp += RRlen[i];
GETSHORT(rdlength, cp);
RRlen[i] += INT16SZ; /*rdlength*/
RRlen[i] += rdlength; /*rdata field*/
dprintf(3, (ddt, "RRlen[%d]=%d\n", i, RRlen[i]));
if (Vlist[i] != INVALID)
newlen += RRlen[i];
cp += rdlength; /*increment pointer to next RR*/
}
hp->ancount = htons(new_ancount);
hp->nscount = htons(new_nscount);
hp->arcount = htons(new_arcount);
/* get new buffer */
dprintf(3, (ddt,
"newlen:%d, if no RR is INVALID == msglen\n", newlen));
newmsg = (u_char *)calloc(1,newlen + MAXDNAME);
if(newmsg == NULL)
goto badend;
dpp = dnptrs;
*dpp++ = newmsg;
*dpp = NULL;
/* bcopy the header, with all the length fields correctly put in */
bcopy((char *)msg, (char*)newmsg, HFIXEDSZ); /*header copied */
newcp = newmsg +HFIXEDSZ; /*need a pointer in the new buffer */
rembuflen = newlen +MAXDNAME - HFIXEDSZ; /*buflen we can workin*/
newlen = HFIXEDSZ; /* this will now contain the length of msg */
n_new = dn_comp(qname, newcp, rembuflen, dnptrs, edp);
if (n_new < 0)
goto badend;
newcp += n_new;
PUTSHORT(type, newcp);
PUTSHORT(class, newcp); /*query section complete*/
newlen += (n_new+2*INT16SZ);
rembuflen -= (n_new+2*INT16SZ);
/* have to decode and copy every Valid RR from here */
cp = msg +HFIXEDSZ +qlen; /*skip header and query section*/
for (i = 0; i < c; i++) {
if (Vlist[i] == INVALID) {
/* go to next RR if this one is not INVALID */
cp += RRlen[i];
continue;
}
/* we have a valid record, must put it in the newmsg */
n = dn_expand(msg, eom, cp, dname, sizeof dname);
if (n < 0) {
hp->rcode = FORMERR;
goto badend;
}
n_new = dn_comp(dname, newcp, rembuflen, dnptrs, edp);
if (n_new < 0)
goto badend;
cp += n;
newcp += n_new;
dprintf(5, (ddt,
"cp:0x%x newcp:0x%x after getting name\n",
cp, newcp));
GETSHORT(type, cp);
PUTSHORT(type, newcp);
dprintf(5, (ddt,
"cp:0x%x newcp:0x%x after getting type\n",
cp, newcp));
GETSHORT(class, cp);
PUTSHORT(class, newcp);
dprintf(5, (ddt,
"cp:0x%x newcp:0x%x after getting class\n",
cp, newcp));
GETLONG(ttl, cp);
PUTLONG(ttl, newcp);
dprintf(5, (ddt,
"cp:0x%x newcp:0x%x after getting ttl\n",
cp, newcp));
/* this will probably be modified for newmsg,
* will put this in later, after compression
*/
GETSHORT(dlen, cp);
newlen += (n_new+3*INT16SZ + INT32SZ);
rembuflen -= (n_new+3*INT16SZ+ INT32SZ);
tempcp = newcp;
newcp += INT16SZ; /*advance to rdata field*/
dprintf(5, (ddt, "tempcp:0x%x newcp:0x%x\n",
tempcp, newcp));
dprintf(3, (ddt,
"update_msg: dname %s type %d class %d ttl %d\n",
dname, type, class, ttl));
/* read off the data section */
switch (type) {
case T_A:
case T_WKS:
case T_HINFO:
case T_UINFO:
case T_UID:
case T_GID:
case T_TXT:
case T_X25:
case T_ISDN:
#ifdef ALLOW_T_UNSPEC
case T_UNSPEC:
#endif
n = dlen;
PUTSHORT(n, tempcp); /*time to put in the dlen*/
bcopy(cp, newcp,n); /*done here*/
cp +=n;
newcp +=n;
newlen += n;
rembuflen -= n;
dprintf(3, (ddt, "\tcp:0x%x newcp:0x%x dlen:%d\n",
cp, newcp, dlen));
break;
case T_CNAME:
case T_MB:
case T_MG:
case T_MR:
case T_NS:
case T_PTR:
/*read off name from data section */
n = dn_expand(msg, eom, cp,
(char *)data, sizeof data);
if (n < 0) {
hp->rcode = FORMERR;
goto badend;
}
cp += n; /*advance pointer*/
/* fill in new packet */
n_new = dn_comp((char *)data, newcp, rembuflen,
dnptrs, edp);
if (n_new < 0)
goto badend;
PUTSHORT(n_new,tempcp); /*put in dlen field*/
newcp += n_new; /*advance new pointer*/
newlen += n_new;
rembuflen -= n_new;
break;
case T_MINFO:
case T_SOA:
case T_RP:
n = dn_expand(msg, eom, cp, (char *)data, sizeof data);
if (n < 0) {
hp->rcode = FORMERR;
goto badend;
}
cp += n;
n_new = dn_comp((char *)data, newcp, rembuflen,
dnptrs, edp);
if (n_new < 0)
goto badend;
newcp += n_new;
newlen += n_new;
rembuflen -= n_new;
dlen = n_new;
n = dn_expand(msg, eom, cp, (char *)data, sizeof data);
if (n < 0) {
hp->rcode = FORMERR;
goto badend;
}
cp += n;
n_new = dn_comp((char *)data, newcp, rembuflen,
dnptrs, edp);
if (n_new < 0)
goto badend;
newcp += n_new;
newlen += n_new;
rembuflen -= n_new;
dlen += n_new;
if (type == T_SOA) {
bcopy(cp, newcp, n = 5*INT32SZ);
cp += n;
newcp += n;
newlen +=n;
rembuflen -= n;
dlen +=n;
}
PUTSHORT(dlen, tempcp);
break;
case T_MX:
case T_AFSDB:
case T_RT:
/* grab preference */
bcopy(cp,newcp,INT16SZ);
cp += INT16SZ;
newcp += INT16SZ;
/* get name */
n = dn_expand(msg, eom, cp, (char *)data, sizeof data);
if (n < 0) {
hp->rcode = FORMERR;
goto badend;
}
cp += n;
n_new = dn_comp((char *)data, newcp, rembuflen,
dnptrs, edp);
if (n_new < 0)
goto badend;
PUTSHORT(n_new+INT16SZ, tempcp);
newcp += n_new;
newlen += n_new+INT16SZ;
rembuflen -= n_new+INT16SZ;
break;
default:
dprintf(3, (ddt, "unknown type %d\n", type));
goto badend;
}
dprintf(2, (ddt,
"newlen:%d, i:%d newcp:0x%x cp:0x%x\n\n",
newlen, i, newcp, cp));
}
bcopy(newmsg, msg, newlen);
n = *msglen - newlen;
if (n < 0) {
dprintf(2, (ddt,
"update_msg():newmsg longer than old: n:%d o:%d ???\n",
newlen, *msglen));
}
*msglen = newlen;
free((char *)newmsg);
#ifdef DEBUG
if (debug >= 10)
fp_query(msg, ddt);
#endif
free((char *)RRlen);
return(n);
badend:
dprintf(2, (ddt, "encountered problems: UPDATE_MSG\n"));
free((char *)RRlen);
return(-1);
}
#endif /*VALIDATE*/
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