ndb/dns: fix leak in myaddr(), normalize ip strings

remove myaddr() function and replace with myip() function
that receives binary ip address. and don't use string
comparsion for ip addresses... parse and then ipcmp().

for sanity reasons, normalize ip address strings and
reject unparsable ones. done by calling ipalookup()
with a binary ip address.

sys/src/cmd/ndb/dblookup.c

@@ -316,8 +316,7 @@ dblookup1(char *name, int type, int auth, int ttl)
 			nstrcpy(dname, nt->val, sizeof dname);
 			found = 1;
 		}
-		if(strcmp(attr, nt->attr) == 0){
+		if(strcmp(attr, nt->attr) == 0 && (rp = (*f)(t, nt)) != nil){
-			rp = (*f)(t, nt);
 			rp->auth = auth;
 			rp->db = 1;
 			if(ttl)
@@ -336,12 +335,11 @@ dblookup1(char *name, int type, int auth, int ttl)
 
 	/* search whole entry */
 	for(nt = t; nt; nt = nt->entry)
-		if(nt->ptr == 0 && strcmp(attr, nt->attr) == 0){
+		if(nt->ptr == 0 && strcmp(attr, nt->attr) == 0 && (rp = (*f)(t, nt)) != nil){
-			rp = (*f)(t, nt);
+			rp->auth = auth;
 			rp->db = 1;
 			if(ttl)
 				rp->ttl = ttl;
-			rp->auth = auth;
 			if(dp == nil)
 				dp = idnlookup(dname, Cin, 1);
 			rp->owner = dp;
@@ -358,26 +356,22 @@ dblookup1(char *name, int type, int auth, int ttl)
  *  make various types of resource records from a database entry
  */
 static RR*
-addrrr(Ndbtuple *entry, Ndbtuple *pair)
+addrrr(Ndbtuple*, Ndbtuple *pair)
 {
 	RR *rp;
-	uchar addr[IPaddrlen];
+	uchar ip[IPaddrlen];
 
-	USED(entry);
+	if(parseip(ip, pair->val) == -1)
-	parseip(addr, pair->val);
+		return nil;
-	if(isv4(addr))
+	rp = rralloc(isv4(ip) ? Ta : Taaaa);
-		rp = rralloc(Ta);
+	rp->ip = ipalookup(ip, Cin, 1);
-	else
-		rp = rralloc(Taaaa);
-	rp->ip = dnlookup(pair->val, Cin, 1);
 	return rp;
 }
 static RR*
-nullrr(Ndbtuple *entry, Ndbtuple *pair)
+nullrr(Ndbtuple*, Ndbtuple *pair)
 {
 	RR *rp;
 
-	USED(entry);
 	rp = rralloc(Tnull);
 	rp->null->data = (uchar*)estrdup(pair->val);
 	rp->null->dlen = strlen((char*)rp->null->data);
@@ -389,13 +383,12 @@ nullrr(Ndbtuple *entry, Ndbtuple *pair)
  *  <= 255 byte ones.
  */
 static RR*
-txtrr(Ndbtuple *entry, Ndbtuple *pair)
+txtrr(Ndbtuple*, Ndbtuple *pair)
 {
 	RR *rp;
 	Txt *t, **l;
 	int i, len, sofar;
 
-	USED(entry);
 	rp = rralloc(Ttxt);
 	l = &rp->txt;
 	rp->txt = nil;
@@ -420,11 +413,10 @@ txtrr(Ndbtuple *entry, Ndbtuple *pair)
 	return rp;
 }
 static RR*
-cnamerr(Ndbtuple *entry, Ndbtuple *pair)
+cnamerr(Ndbtuple*, Ndbtuple *pair)
 {
 	RR *rp;
 
-	USED(entry);
 	rp = rralloc(Tcname);
 	rp->host = idnlookup(pair->val, Cin, 1);
 	return rp;
@@ -453,11 +445,10 @@ nsrr(Ndbtuple *entry, Ndbtuple *pair)
 	return rp;
 }
 static RR*
-ptrrr(Ndbtuple *entry, Ndbtuple *pair)
+ptrrr(Ndbtuple*, Ndbtuple *pair)
 {
 	RR *rp;
 
-	USED(entry);
 	rp = rralloc(Tns);
 	rp->ptr = dnlookup(pair->val, Cin, 1);
 	return rp;
@@ -815,33 +806,29 @@ baddelegation(RR *rp, RR *nsrp, uchar *addr)
 }
 
 int
-myaddr(char *addr)
+myip(uchar *ip)
 {
 	char *line, *sp;
-	char buf[64];
+	char buf[Maxpath];
+	uchar ipa[IPaddrlen];
 	Biobuf *bp;
 
 	if(ipcmp(ipaddr, IPnoaddr) == 0)
 		if(myipaddr(ipaddr, mntpt) < 0)
 			return -1;
 
-	snprint(buf, sizeof buf, "%I", ipaddr);
+	if(ipcmp(ipaddr, ip) == 0)
-	if (strcmp(addr, buf) == 0) {
-		dnslog("rejecting my ip %s as local dns server", addr);
 		return 1;
-	}
 
 	snprint(buf, sizeof buf, "%s/ipselftab", mntpt);
 	bp = Bopen(buf, OREAD);
-	if (bp != nil) {
+	if(bp != nil) {
-		while ((line = Brdline(bp, '\n')) != nil) {
+		while((line = Brdline(bp, '\n')) != nil) {
 			line[Blinelen(bp) - 1] = '\0';
-			sp = strchr(line, ' ');
+			if((sp = strchr(line, ' ')) != nil) {
-			if (sp) {
 				*sp = '\0';
-				if (strcmp(addr, line) == 0) {
+				if(parseip(ipa, line) != -1 && ipcmp(ipa, ip) == 0) {
-					dnslog("rejecting my ip %s as local dns server",
+					Bterm(bp);
-						addr);
 					return 1;
 				}
 			}
@@ -851,39 +838,52 @@ myaddr(char *addr)
 	return 0;
 }
 
-static char *locdns[20];
-static QLock locdnslck;
-
 static void
 addlocaldnsserver(DN *dp, int class, char *ipaddr, int i)
 {
-	int n;
-	DN *nsdp;
-	RR *rp;
-	char buf[32];
 	uchar ip[IPaddrlen];
+	DN *nsdp, *ipdp;
+	RR *rp, *tp;
+	int type, n;
+	char buf[32];
 
-	/* reject our own ip addresses so we don't query ourselves via udp */
+	if(parseip(ip, ipaddr) == -1 || ipcmp(ip, IPnoaddr) == 0){
-	if (myaddr(ipaddr))
+		dnslog("rejecting bad ip %s as local dns server", ipaddr);
-		return;
-
-	qlock(&locdnslck);
-	for (n = 0; n < i && n < nelem(locdns) && locdns[n]; n++)
-		if (strcmp(locdns[n], ipaddr) == 0) {
-			dnslog("rejecting duplicate local dns server ip %s",
-				ipaddr);
-			qunlock(&locdnslck);
 		return;
 	}
-	if (n < nelem(locdns))
+
-		if (locdns[n] == nil || ++n < nelem(locdns))
+	/* reject our own ip addresses so we don't query ourselves via udp */
-			locdns[n] = strdup(ipaddr); /* remember 1st few local ns */
+	if(myip(ip)){
-	qunlock(&locdnslck);
+		dnslog("rejecting my ip %I as local dns server", ip);
+		return;
+	}
+
+	/* A or AAAA record */
+	type = isv4(ip) ? Ta : Taaaa;
+	ipdp = ipalookup(ip, class, 1);
+
+	/* check duplicate ip */
+	for(n = 0; n < i; n++){
+		snprint(buf, sizeof buf, "local#dns#server%d", n);
+		nsdp = dnlookup(buf, class, 0);
+		if(nsdp == nil)
+			continue;
+		rp = rrlookup(nsdp, type, NOneg);
+		for(tp = rp; tp != nil; tp = tp->next){
+			if(tp->ip == ipdp){
+				dnslog("rejecting duplicate local dns server ip %I", ip);
+				rrfreelist(rp);
+				return;
+			}
+		}
+		rrfreelist(rp);
+	}
+
+	snprint(buf, sizeof buf, "local#dns#server%d", i);
+	nsdp = dnlookup(buf, class, 1);
 
 	/* ns record for name server, make up an impossible name */
 	rp = rralloc(Tns);
-	snprint(buf, sizeof buf, "local#dns#server%d", i);
-	nsdp = dnlookup(buf, class, 1);
 	rp->host = nsdp;
 	rp->owner = dp;			/* e.g., local#dns#servers */
 	rp->local = 1;
@@ -892,12 +892,8 @@ addlocaldnsserver(DN *dp, int class, char *ipaddr, int i)
 	rrattach(rp, Authoritative);	/* will not attach rrs in my area */
 	dnagenever(dp);
 
-	/* A or AAAA record */
+	rp = rralloc(type);
-	if (parseip(ip, ipaddr) >= 0 && isv4(ip))
+	rp->ip = ipdp;
-		rp = rralloc(Ta);
-	else
-		rp = rralloc(Taaaa);
-	rp->ip = dnlookup(ipaddr, class, 1);
 	rp->owner = nsdp;
 	rp->local = 1;
 	rp->db = 1;
@@ -905,7 +901,7 @@ addlocaldnsserver(DN *dp, int class, char *ipaddr, int i)
 	rrattach(rp, Authoritative);	/* will not attach rrs in my area */
 	dnagenever(nsdp);
 
-	dnslog("added local dns server %s at %s", buf, ipaddr);
+	dnslog("added local dns server %s at %I", buf, ip);
 }
 
 /*
@@ -917,7 +913,7 @@ dnsservers(int class)
 {
 	int i, n;
 	char *p;
-	char *args[5];
+	char *args[16];
 	Ndbtuple *t, *nt;
 	RR *nsrp;
 	DN *dp;
@@ -1208,8 +1204,7 @@ insidens(uchar *ip)
 
 	for (t = innmsrvs; t != nil; t = t->entry)
 		if (strcmp(t->attr, "ip") == 0) {
-			parseip(ipa, t->val);
+			if (parseip(ipa, t->val) != -1 && ipcmp(ipa, ip) == 0)
-			if (memcmp(ipa, ip, sizeof ipa) == 0)
 				return 1;
 		}
 	return 0;
@@ -1224,7 +1219,8 @@ outsidensip(int n, uchar *ip)
 	i = 0;
 	for (t = outnmsrvs; t != nil; t = t->entry)
 		if (strcmp(t->attr, "ip") == 0 && i++ == n) {
-			parseip(ip, t->val);
+			if (parseip(ip, t->val) == -1)
+				return -1;
 			return 0;
 		}
 	return -1;

sys/src/cmd/ndb/dn.c

@@ -233,6 +233,15 @@ idnlookup(char *name, int class, int enter)
 	return dnlookup(name, class, enter);
 }
 
+DN*
+ipalookup(uchar *ip, int class, int enter)
+{
+	char addr[64];
+
+	snprint(addr, sizeof(addr), "%I", ip);
+	return dnlookup(addr, class, enter);
+}
+
 static int
 rrsame(RR *rr1, RR *rr2)
 {

sys/src/cmd/ndb/dnresolve.c

@@ -922,13 +922,12 @@ static int
 mydnsquery(Query *qp, int medium, uchar *udppkt, int len)
 {
 	int rv, nfd;
-	char conndir[40], addr[128], domain[64];
+	char conndir[40], addr[128];
 	uchar belen[2];
 	NetConnInfo *nci;
 
 	rv = -1;
-	snprint(domain, sizeof(domain), "%I", udppkt);
+	if (myip(udppkt))
-	if (myaddr(domain))
 		return rv;
 	switch (medium) {
 	case Udp:
@@ -958,9 +957,8 @@ mydnsquery(Query *qp, int medium, uchar *udppkt, int len)
 	case Tcp:
 		/* send via TCP & keep fd around for reply */
 		memmove(qp->tcpip, udppkt, sizeof qp->tcpip);
-		snprint(addr, sizeof addr, "%s/tcp!%s!dns",
+		snprint(addr, sizeof addr, "%s/tcp!%I!dns",
-				(mntpt && *mntpt) ? mntpt : "/net",
+			(mntpt && *mntpt) ? mntpt : "/net", udppkt);
-				domain);
 		alarm(10*1000);
 		qp->tcpfd = dial(addr, nil, conndir, &qp->tcpctlfd);
 		alarm(0);
@@ -1049,7 +1047,7 @@ xmitquery(Query *qp, int medium, int depth, uchar *obuf, int inns, int len)
 		if((1<<p->nx) > qp->ndest)
 			continue;
 
-		if(memcmp(p->a, IPnoaddr, sizeof IPnoaddr) == 0)
+		if(ipcmp(p->a, IPnoaddr) == 0)
 			continue;		/* mistake */
 
 		procsetname("udp %sside query to %I/%s %s %s",
@@ -1387,7 +1385,7 @@ queryns(Query *qp, int depth, uchar *ibuf, uchar *obuf, ulong waitms, int inns)
 			if(debug)
 				dnslog("queryns got reply from %I", srcip);
 			for(p = qp->dest; p < qp->curdest; p++)
-				if(memcmp(p->a, srcip, sizeof p->a) == 0)
+				if(ipcmp(p->a, srcip) == 0)
 					break;
 			if(p >= qp->curdest){
 				dnslog("response from %I but no destination", srcip);

sys/src/cmd/ndb/dns.h

@@ -449,13 +449,12 @@ void	dnagedb(void);
 void	dnagenever(DN *);
 void	dnauthdb(void);
 void	dndump(char*);
-void	dnget(void);
 void	dninit(void);
 DN*	dnlookup(char*, int, int);
 DN*	idnlookup(char*, int, int);
+DN*	ipalookup(uchar*, int, int);
 void	dnptr(uchar*, uchar*, char*, int, int, int);
 void	dnpurge(void);
-void	dnput(void);
 void	dnslog(char*, ...);
 void	dnstats(char *file);
 void*	emalloc(int);
@@ -501,7 +500,7 @@ RR*	dnsservers(int);
 RR*	domainlist(int);
 int	insideaddr(char *dom);
 int	insidens(uchar *ip);
-int	myaddr(char *addr);
+int	myip(uchar *ip);
 int	opendatabase(void);
 int	outsidensip(int, uchar *ip);