From 2cb0cc3c4768ba4c8f00a0241393a77a5ed06233 Mon Sep 17 00:00:00 2001
From: Marcelo Araujo <araujo@FreeBSD.org>
Date: Mon, 21 Dec 2015 14:32:29 +0000
Subject: [PATCH] MFC: r291073

If a NIS server has long entries on its database that is bigger than
1024 specified on YPMAXRECORD the ypmatch can get in an infinite retry
loop when is requesting the information from the NIS server.

The ypmatch(1) will return an error until the command receives an
kill(1).

To avoid this problem, we check the MAX_RETRIES that is by default set
to 20 and avoid get in infinet loop at the client side.

NOTE: FreeBSD nis(8) server doesn't present this issue.

Submitted by:   Ravi Pokala <rpokala at panasas.com>,
                Lakshmi N. Sundararajan <lakshmi.n at msystechnologies.com>,
                Lewis, Fred <flewis at panasas.com>,
                Pushkar Kothavade <pushkar.kothavade at msystechnologies.com>
---
 lib/libc/yp/yplib.c | 33 ++++++++++++++++++++++++++++-----
 1 file changed, 28 insertions(+), 5 deletions(-)

diff --git a/lib/libc/yp/yplib.c b/lib/libc/yp/yplib.c
index 1778c6a6a3ba..1a6df692ef62 100644
--- a/lib/libc/yp/yplib.c
+++ b/lib/libc/yp/yplib.c
@@ -655,7 +655,7 @@ yp_match(char *indomain, char *inmap, const char *inkey, int inkeylen,
 	struct timeval tv;
 	struct ypreq_key yprk;
 	int r;
-
+	int retries = 0;
 	*outval = NULL;
 	*outvallen = 0;
 
@@ -700,6 +700,11 @@ yp_match(char *indomain, char *inmap, const char *inkey, int inkeylen,
 #endif
 
 again:
+	if (retries > MAX_RETRIES) {
+		YPUNLOCK();
+		return (YPERR_RPC);
+	}
+
 	if (_yp_dobind(indomain, &ysd) != 0) {
 		YPUNLOCK();
 		return (YPERR_DOMAIN);
@@ -716,6 +721,7 @@ again:
 	if (r != RPC_SUCCESS) {
 		clnt_perror(ysd->dom_client, "yp_match: clnt_call");
 		_yp_unbind(ysd);
+		retries++;
 		goto again;
 	}
 
@@ -772,7 +778,7 @@ yp_first(char *indomain, char *inmap, char **outkey, int *outkeylen,
 	struct dom_binding *ysd;
 	struct timeval tv;
 	int r;
-
+	int retries = 0;
 	/* Sanity check */
 
 	if (indomain == NULL || !strlen(indomain) ||
@@ -784,6 +790,11 @@ yp_first(char *indomain, char *inmap, char **outkey, int *outkeylen,
 
 	YPLOCK();
 again:
+	if (retries > MAX_RETRIES) {
+		YPUNLOCK();
+		return (YPERR_RPC);
+	}
+
 	if (_yp_dobind(indomain, &ysd) != 0) {
 		YPUNLOCK();
 		return (YPERR_DOMAIN);
@@ -802,6 +813,7 @@ again:
 	if (r != RPC_SUCCESS) {
 		clnt_perror(ysd->dom_client, "yp_first: clnt_call");
 		_yp_unbind(ysd);
+		retries++;
 		goto again;
 	}
 	if (!(r = ypprot_err(yprkv.stat))) {
@@ -844,7 +856,7 @@ yp_next(char *indomain, char *inmap, char *inkey, int inkeylen,
 	struct dom_binding *ysd;
 	struct timeval tv;
 	int r;
-
+	int retries = 0;
 	/* Sanity check */
 
 	if (inkey == NULL || !strlen(inkey) || inkeylen <= 0 ||
@@ -857,6 +869,11 @@ yp_next(char *indomain, char *inmap, char *inkey, int inkeylen,
 
 	YPLOCK();
 again:
+	if (retries > MAX_RETRIES) {
+		YPUNLOCK();
+		return (YPERR_RPC);
+	}
+
 	if (_yp_dobind(indomain, &ysd) != 0) {
 		YPUNLOCK();
 		return (YPERR_DOMAIN);
@@ -877,6 +894,7 @@ again:
 	if (r != RPC_SUCCESS) {
 		clnt_perror(ysd->dom_client, "yp_next: clnt_call");
 		_yp_unbind(ysd);
+		retries++;
 		goto again;
 	}
 	if (!(r = ypprot_err(yprkv.stat))) {
@@ -920,7 +938,7 @@ yp_all(char *indomain, char *inmap, struct ypall_callback *incallback)
 	CLIENT *clnt;
 	u_long status, savstat;
 	int clnt_sock;
-
+	int retries = 0;
 	/* Sanity check */
 
 	if (indomain == NULL || !strlen(indomain) ||
@@ -929,6 +947,10 @@ yp_all(char *indomain, char *inmap, struct ypall_callback *incallback)
 
 	YPLOCK();
 again:
+	if (retries > MAX_RETRIES) {
+		YPUNLOCK();
+		return (YPERR_RPC);
+	}
 
 	if (_yp_dobind(indomain, &ysd) != 0) {
 		YPUNLOCK();
@@ -958,9 +980,10 @@ again:
 	if (clnt_call(clnt, YPPROC_ALL,
 		(xdrproc_t)xdr_ypreq_nokey, &yprnk,
 		(xdrproc_t)xdr_ypresp_all_seq, &status, tv) != RPC_SUCCESS) {
-			clnt_perror(ysd->dom_client, "yp_all: clnt_call");
+			clnt_perror(clnt, "yp_all: clnt_call");
 			clnt_destroy(clnt);
 			_yp_unbind(ysd);
+			retries++;
 			goto again;
 	}