Allocate 64K recieve buffer for DNS responses.

Though res_query.c also defines and refers MAXPACKET, it is not
related to ansbuf.  So, I didn't touch res_query.c.

2 files changed, 50 insertions, 26 deletions

diff --git a/lib/libc/net/gethostbydns.c b/lib/libc/net/gethostbydns.c
index 0effbe4..d55ea89 100644
--- a/lib/libc/net/gethostbydns.c
+++ b/lib/libc/net/gethostbydns.c
@@ -68,6 +68,7 @@ __FBSDID("$FreeBSD$");
 #include <arpa/nameser.h>
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <unistd.h>
 #include <string.h>
 #include <netdb.h>
@@ -103,11 +104,7 @@ static void addrsort(char **, int);
 static void dprintf(char *, int) __printflike(1, 0);
 #endif
 
-#if PACKETSZ > 1024
-#define	MAXPACKET	PACKETSZ
-#else
-#define	MAXPACKET	1024
-#endif
+#define MAXPACKET	(64*1024)
 
 typedef union {
     HEADER hdr;
@@ -477,7 +474,7 @@ _dns_gethostbyname(void *rval, void *cb_data, va_list ap)
 {
 	const char *name;
 	int af;
-	querybuf buf;
+	querybuf *buf;
 	const char *cp;
 	char *bp, *ep;
 	int n, size, type, len;
@@ -587,15 +584,22 @@ _dns_gethostbyname(void *rval, void *cb_data, va_list ap)
 				break;
 		}
 
-	n = res_search(name, C_IN, type, buf.buf, sizeof(buf.buf));
+	if ((buf = malloc(sizeof(*buf))) == NULL) {
+		h_errno = NETDB_INTERNAL;
+		return NS_NOTFOUND;
+	}
+	n = res_search(name, C_IN, type, buf->buf, sizeof(buf->buf));
 	if (n < 0) {
+		free(buf);
 		dprintf("res_search failed (%d)\n", n);
 		return (NULL);
-	} else if (n > sizeof(buf.buf)) {
+	} else if (n > sizeof(buf->buf)) {
+		free(buf);
 		dprintf("static buffer is too small (%d)\n", n);
 		return (NULL);
 	}
-	*(struct hostent **)rval = gethostanswer(&buf, n, name, type);
+	*(struct hostent **)rval = gethostanswer(buf, n, name, type);
+	free(buf);
 	return (*(struct hostent **)rval != NULL) ? NS_SUCCESS : NS_NOTFOUND;
 }
 
@@ -608,7 +612,7 @@ _dns_gethostbyaddr(void *rval, void *cb_data, va_list ap)
 	static const u_char mapped[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0xff,0xff };
 	static const u_char tunnelled[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0,0 };
 	int n, size;
-	querybuf buf;
+	querybuf *buf;
 	struct hostent *hp;
 	char qbuf[MAXDNAME+1], *qp;
 #ifdef SUNSECURITY
@@ -675,17 +679,26 @@ _dns_gethostbyaddr(void *rval, void *cb_data, va_list ap)
 	default:
 		abort();
 	}
-	n = res_query(qbuf, C_IN, T_PTR, (u_char *)buf.buf, sizeof buf.buf);
+	if ((buf = malloc(sizeof(*buf))) == NULL) {
+		h_errno = NETDB_INTERNAL;
+		return NS_NOTFOUND;
+	}
+	n = res_query(qbuf, C_IN, T_PTR, (u_char *)buf->buf, sizeof buf->buf);
 	if (n < 0) {
+		free(buf);
 		dprintf("res_query failed (%d)\n", n);
 		return NS_UNAVAIL;
 	}
-	if (n > sizeof buf.buf) {
+	if (n > sizeof buf->buf) {
+		free(buf);
 		dprintf("static buffer is too small (%d)\n", n);
 		return NS_UNAVAIL;
 	}
-	if (!(hp = gethostanswer(&buf, n, qbuf, T_PTR)))
+	if (!(hp = gethostanswer(buf, n, qbuf, T_PTR))) {
+		free(buf);
 		return NS_NOTFOUND;   /* h_errno was set by gethostanswer() */
+	}
+	free(buf);
 #ifdef SUNSECURITY
 	if (af == AF_INET) {
 	    /*
diff --git a/lib/libc/net/getnetbydns.c b/lib/libc/net/getnetbydns.c
index 6e70ece..6b72c43 100644
--- a/lib/libc/net/getnetbydns.c
+++ b/lib/libc/net/getnetbydns.c
@@ -71,6 +71,7 @@ __FBSDID("$FreeBSD$");
 #include <arpa/nameser.h>
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <netdb.h>
 #include <resolv.h>
 #include <ctype.h>
@@ -88,11 +89,7 @@ extern int h_errno;
 #define BYNAME 1
 #define	MAXALIASES	35
 
-#if PACKETSZ > 1024
-#define	MAXPACKET	PACKETSZ
-#else
-#define	MAXPACKET	1024
-#endif
+#define MAXPACKET	(64*1024)
 
 typedef union {
 	HEADER	hdr;
@@ -228,7 +225,7 @@ _dns_getnetbyaddr(void *rval, void *cb_data, va_list ap)
 	int net_type;
 	unsigned int netbr[4];
 	int nn, anslen;
-	querybuf buf;
+	querybuf *buf;
 	char qbuf[MAXDNAME];
 	unsigned long net2;
 	struct netent *net_entry;
@@ -259,21 +256,28 @@ _dns_getnetbyaddr(void *rval, void *cb_data, va_list ap)
 		    netbr[1], netbr[0]);
 		break;
 	}
-	anslen = res_query(qbuf, C_IN, T_PTR, (u_char *)&buf, sizeof(buf));
+	if ((buf = malloc(sizeof(*buf))) == NULL) {
+		h_errno = NETDB_INTERNAL;
+		return NS_NOTFOUND;
+	}
+	anslen = res_query(qbuf, C_IN, T_PTR, (u_char *)buf, sizeof(*buf));
 	if (anslen < 0) {
+		free(buf);
 #ifdef DEBUG
 		if (_res.options & RES_DEBUG)
 			printf("res_search failed\n");
 #endif
 		return NS_UNAVAIL;
-	} else if (anslen > sizeof(buf)) {
+	} else if (anslen > sizeof(*buf)) {
+		free(buf);
 #ifdef DEBUG
 		if (_res.options & RES_DEBUG)
 			printf("res_search static buffer too small\n");
 #endif
 		return NS_UNAVAIL;
 	}
-	net_entry = getnetanswer(&buf, anslen, BYADDR);
+	net_entry = getnetanswer(buf, anslen, BYADDR);
+	free(buf);
 	if (net_entry) {
 		unsigned u_net = net;	/* maybe net should be unsigned ? */
 
@@ -292,7 +296,7 @@ _dns_getnetbyname(void *rval, void *cb_data, va_list ap)
 {
 	const char *net;
 	int anslen;
-	querybuf buf;
+	querybuf *buf;
 	char qbuf[MAXDNAME];
 
 	net = va_arg(ap, const char *);
@@ -303,23 +307,30 @@ _dns_getnetbyname(void *rval, void *cb_data, va_list ap)
 		h_errno = NETDB_INTERNAL;
 		return NS_UNAVAIL;
 	}
+	if ((buf = malloc(sizeof(*buf))) == NULL) {
+		h_errno = NETDB_INTERNAL;
+		return NS_NOTFOUND;
+	}
 	strncpy(qbuf, net, sizeof(qbuf) - 1);
 	qbuf[sizeof(qbuf) - 1] = '\0';
-	anslen = res_search(qbuf, C_IN, T_PTR, (u_char *)&buf, sizeof(buf));
+	anslen = res_search(qbuf, C_IN, T_PTR, (u_char *)buf, sizeof(*buf));
 	if (anslen < 0) {
+		free(buf);
 #ifdef DEBUG
 		if (_res.options & RES_DEBUG)
 			printf("res_search failed\n");
 #endif
 		return NS_UNAVAIL;
-	} else if (anslen > sizeof(buf)) {
+	} else if (anslen > sizeof(*buf)) {
+		free(buf);
 #ifdef DEBUG
 		if (_res.options & RES_DEBUG)
 			printf("res_search static buffer too small\n");
 #endif
 		return NS_UNAVAIL;
 	}
-	*(struct netent**)rval = getnetanswer(&buf, anslen, BYNAME);
+	*(struct netent**)rval = getnetanswer(buf, anslen, BYNAME);
+	free(buf);
 	return (*(struct netent**)rval != NULL) ? NS_SUCCESS : NS_NOTFOUND;
 }