ref: 549a6745e3b6a69c9a14deb5090b8fa1ad444f06
parent: b3b938d5ecb39e0548ab811ee1099e6dda67052f
author: cinap_lenrek <cinap_lenrek@felloff.net>
date: Sun Jan 28 17:36:01 EST 2018
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.
--- a/sys/src/cmd/ndb/dblookup.c
+++ b/sys/src/cmd/ndb/dblookup.c
@@ -316,8 +316,7 @@
nstrcpy(dname, nt->val, sizeof dname);
found = 1;
}
- if(strcmp(attr, nt->attr) == 0){- rp = (*f)(t, nt);
+ if(strcmp(attr, nt->attr) == 0 && (rp = (*f)(t, nt)) != nil){rp->auth = auth;
rp->db = 1;
if(ttl)
@@ -336,12 +335,11 @@
/* search whole entry */
for(nt = t; nt; nt = nt->entry)
- if(nt->ptr == 0 && strcmp(attr, nt->attr) == 0){- rp = (*f)(t, nt);
+ if(nt->ptr == 0 && strcmp(attr, nt->attr) == 0 && (rp = (*f)(t, nt)) != nil){+ 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 @@
* 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);
- parseip(addr, pair->val);
- if(isv4(addr))
- rp = rralloc(Ta);
- else
- rp = rralloc(Taaaa);
- rp->ip = dnlookup(pair->val, Cin, 1);
+ if(parseip(ip, pair->val) == -1)
+ return nil;
+ rp = rralloc(isv4(ip) ? Ta : Taaaa);
+ rp->ip = ipalookup(ip, 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 @@
* <= 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 @@
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 @@
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;
@@ -815,10 +806,11 @@
}
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)
@@ -825,23 +817,18 @@
if(myipaddr(ipaddr, mntpt) < 0)
return -1;
- snprint(buf, sizeof buf, "%I", ipaddr);
- if (strcmp(addr, buf) == 0) {- dnslog("rejecting my ip %s as local dns server", addr);+ if(ipcmp(ipaddr, ip) == 0)
return 1;
- }
snprint(buf, sizeof buf, "%s/ipselftab", mntpt);
bp = Bopen(buf, OREAD);
- if (bp != nil) {- while ((line = Brdline(bp, '\n')) != nil) {+ if(bp != nil) {+ while((line = Brdline(bp, '\n')) != nil) {line[Blinelen(bp) - 1] = '\0';
- sp = strchr(line, ' ');
- if (sp) {+ if((sp = strchr(line, ' ')) != nil) {*sp = '\0';
- if (strcmp(addr, line) == 0) {- dnslog("rejecting my ip %s as local dns server",- addr);
+ if(parseip(ipa, line) != -1 && ipcmp(ipa, ip) == 0) {+ Bterm(bp);
return 1;
}
}
@@ -851,39 +838,52 @@
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];
+ if(parseip(ip, ipaddr) == -1 || ipcmp(ip, IPnoaddr) == 0){+ dnslog("rejecting bad ip %s as local dns server", ipaddr);+ return;
+ }
+
/* reject our own ip addresses so we don't query ourselves via udp */
- if (myaddr(ipaddr))
+ if(myip(ip)){+ dnslog("rejecting my ip %I as local dns server", ip);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;
+ /* 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;
+ }
}
- if (n < nelem(locdns))
- if (locdns[n] == nil || ++n < nelem(locdns))
- locdns[n] = strdup(ipaddr); /* remember 1st few local ns */
- qunlock(&locdnslck);
+ rrfreelist(rp);
+ }
- /* 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);
+
+ /* ns record for name server, make up an impossible name */
+ rp = rralloc(Tns);
rp->host = nsdp;
rp->owner = dp; /* e.g., local#dns#servers */
rp->local = 1;
@@ -892,12 +892,8 @@
rrattach(rp, Authoritative); /* will not attach rrs in my area */
dnagenever(dp);
- /* A or AAAA record */
- if (parseip(ip, ipaddr) >= 0 && isv4(ip))
- rp = rralloc(Ta);
- else
- rp = rralloc(Taaaa);
- rp->ip = dnlookup(ipaddr, class, 1);
+ rp = rralloc(type);
+ rp->ip = ipdp;
rp->owner = nsdp;
rp->local = 1;
rp->db = 1;
@@ -905,7 +901,7 @@
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 @@
{int i, n;
char *p;
- char *args[5];
+ char *args[16];
Ndbtuple *t, *nt;
RR *nsrp;
DN *dp;
@@ -1208,8 +1204,7 @@
for (t = innmsrvs; t != nil; t = t->entry)
if (strcmp(t->attr, "ip") == 0) {- parseip(ipa, t->val);
- if (memcmp(ipa, ip, sizeof ipa) == 0)
+ if (parseip(ipa, t->val) != -1 && ipcmp(ipa, ip) == 0)
return 1;
}
return 0;
@@ -1224,7 +1219,8 @@
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;
--- a/sys/src/cmd/ndb/dn.c
+++ b/sys/src/cmd/ndb/dn.c
@@ -233,6 +233,15 @@
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)
{--- a/sys/src/cmd/ndb/dnresolve.c
+++ b/sys/src/cmd/ndb/dnresolve.c
@@ -922,13 +922,12 @@
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 (myaddr(domain))
+ if (myip(udppkt))
return rv;
switch (medium) {case Udp:
@@ -958,9 +957,8 @@
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",
- (mntpt && *mntpt) ? mntpt : "/net",
- domain);
+ snprint(addr, sizeof addr, "%s/tcp!%I!dns",
+ (mntpt && *mntpt) ? mntpt : "/net", udppkt);
alarm(10*1000);
qp->tcpfd = dial(addr, nil, conndir, &qp->tcpctlfd);
alarm(0);
@@ -1049,7 +1047,7 @@
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 @@
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);--- a/sys/src/cmd/ndb/dns.h
+++ b/sys/src/cmd/ndb/dns.h
@@ -449,13 +449,12 @@
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* 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);