Increase YPMAXRECORD to 16M to be compatible with Linux.

Since YP protocol definition uses the constant to declare
variable-size opaque byte strings, the change should be binary
compatible with existing installations which do not expose keys or
values larger than 1024 bytes.

All uses of local variables with YPMAXRECORD sizes were removed to
avoid insane stack use.  On the other hand, variables with static
lifetime should be fine and only result in increased VA use.

Glibc made same change, increasing the allowed length for keys and
values in YP to 16M, in 2013.

Reviewed by:	markj
Discussed with:	ian
Sponsored by:	Mellanox Technologies
MFC after:	3 weeks
Differential revision:	https://reviews.freebsd.org/D20900

1 files changed, 27 insertions, 12 deletions

diff --git a/usr.sbin/rpc.yppasswdd/yppasswdd_server.c b/usr.sbin/rpc.yppasswdd/yppasswdd_server.c
index 2e0b52d3e0d4..56c8defc3ba7 100644
--- a/usr.sbin/rpc.yppasswdd/yppasswdd_server.c
+++ b/usr.sbin/rpc.yppasswdd/yppasswdd_server.c
@@ -323,15 +323,16 @@ update_inplace(struct passwd *pw, char *domain)
 	DB *dbp = NULL;
 	DBT key = { NULL, 0 };
 	DBT data = { NULL, 0 };
-	char pwbuf[YPMAXRECORD];
+	char *pwbuf;
 	char keybuf[20];
 	int i;
 	char *ptr = NULL;
 	static char yp_last[] = "YP_LAST_MODIFIED";
-	char yplastbuf[YPMAXRECORD];
+	char yplastbuf[64];
 
 	snprintf(yplastbuf, sizeof yplastbuf, "%llu",
 	    (unsigned long long)time(NULL));
+	pwbuf = NULL;
 
 	for (i = 0; i < 4; i++) {
 
@@ -364,12 +365,12 @@ update_inplace(struct passwd *pw, char *domain)
 		if (yp_get_record(domain,maps[i],&key,&data,1) != YP_TRUE) {
 			yp_error("couldn't read %s/%s: %s", domain,
 						maps[i], strerror(errno));
-			return(1);
+			goto ret1;
 		}
 
 		if ((ptr = strchr(data.data, ':')) == NULL) {
 			yp_error("no colon in passwd record?!");
-			return(1);
+			goto ret1;
 		}
 
 		/*
@@ -393,8 +394,12 @@ with the same UID - continuing");
 			 * We're really being ultra-paranoid here.
 			 * This is generally a 'can't happen' condition.
 			 */
-			snprintf(pwbuf, sizeof pwbuf, ":%d:%d:", pw->pw_uid,
-								  pw->pw_gid);
+			free(pwbuf);
+			asprintf(&pwbuf, ":%d:%d:", pw->pw_uid, pw->pw_gid);
+			if (pwbuf == NULL) {
+				yp_error("no memory");
+				goto ret1;
+			}
 			if (!strstr(data.data, pwbuf)) {
 				yp_error("warning: found entry for user %s \
 in map %s@%s with wrong UID", pw->pw_name, maps[i], domain);
@@ -405,24 +410,30 @@ with the same name - continuing");
 		}
 
 		if (i < 2) {
-			snprintf(pwbuf, sizeof pwbuf, formats[i],
+			free(pwbuf);
+			asprintf(&pwbuf, formats[i],
 			   pw->pw_name, pw->pw_passwd, pw->pw_uid,
 			   pw->pw_gid, pw->pw_class, pw->pw_change,
 			   pw->pw_expire, pw->pw_gecos, pw->pw_dir,
 			   pw->pw_shell);
 		} else {
-			snprintf(pwbuf, sizeof pwbuf, formats[i],
+			free(pwbuf);
+			asprintf(&pwbuf, formats[i],
 			   pw->pw_name, *(ptr+1) == '*' ? "*" : pw->pw_passwd,
 			   pw->pw_uid, pw->pw_gid, pw->pw_gecos, pw->pw_dir,
 			   pw->pw_shell);
 		}
+		if (pwbuf == NULL) {
+			yp_error("no memory");
+			goto ret1;
+		}
 
 #define FLAGS O_RDWR|O_CREAT
 
 		if ((dbp = yp_open_db_rw(domain, maps[i], FLAGS)) == NULL) {
 			yp_error("couldn't open %s/%s r/w: %s",domain,
 						maps[i],strerror(errno));
-			return(1);
+			goto ret1;
 		}
 
 		data.data = pwbuf;
@@ -432,7 +443,7 @@ with the same name - continuing");
 			yp_error("failed to update record in %s/%s", domain,
 								maps[i]);
 			(void)(dbp->close)(dbp);
-			return(1);
+			goto ret1;
 		}
 
 		key.data = yp_last;
@@ -444,13 +455,17 @@ with the same name - continuing");
 			yp_error("failed to update timestamp in %s/%s", domain,
 								maps[i]);
 			(void)(dbp->close)(dbp);
-			return(1);
+			goto ret1;
 		}
 
 		(void)(dbp->close)(dbp);
 	}
 
-	return(0);
+	free(pwbuf);
+	return (0);
+ret1:
+	free(pwbuf);
+	return (1);
 }
 
 int *