Add set_rpc_maxgrouplist

lib/libc/rpc/Makefile.inc

@@ -1,4 +1,4 @@
-#	$NetBSD: Makefile.inc,v 1.26 2019/10/13 07:28:10 mrg Exp $
+#	$NetBSD: Makefile.inc,v 1.27 2020/10/03 18:31:29 christos Exp $
 
 # librpc sources
 .PATH:	${.CURDIR}/rpc
@@ -38,6 +38,7 @@ MLINKS+=	bindresvport.3 bindresvport_sa.3 \
 		rpc_clnt_auth.3 authnone_create.3 \
 		rpc_clnt_auth.3 authsys_create.3 \
 		rpc_clnt_auth.3 authsys_create_default.3 \
+		rpc_clnt_auth.3 set_rpc_maxgrouplist.3 \
 		rpc_clnt_calls.3 clnt_call.3 \
 		rpc_clnt_calls.3 clnt_perrno.3 \
 		rpc_clnt_calls.3 clnt_perror.3 \

lib/libc/rpc/auth_unix.c

@@ -1,4 +1,4 @@
-/*	$NetBSD: auth_unix.c,v 1.26 2014/10/18 08:33:23 snj Exp $	*/
+/*	$NetBSD: auth_unix.c,v 1.27 2020/10/03 18:31:29 christos Exp $	*/
 
 /*
  * Copyright (c) 2010, Oracle America, Inc.
@@ -37,7 +37,7 @@
 static char *sccsid = "@(#)auth_unix.c 1.19 87/08/11 Copyr 1984 Sun Micro";
 static char *sccsid = "@(#)auth_unix.c	2.2 88/08/01 4.0 RPCSRC";
 #else
-__RCSID("$NetBSD: auth_unix.c,v 1.26 2014/10/18 08:33:23 snj Exp $");
+__RCSID("$NetBSD: auth_unix.c,v 1.27 2020/10/03 18:31:29 christos Exp $");
 #endif
 #endif
 
@@ -182,6 +182,20 @@ authunix_create(char *machname, int uid, int gid, int len, int *aup_gids)
 #endif
 }
 
+/*
+ * Some servers will refuse mounts if the group list is larger
+ * than it expects (like 8). This allows the application to set
+ * the maximum size of the group list that will be sent.
+ */
+static int maxgrplist = NGROUPS;
+
+void
+set_rpc_maxgrouplist(int num)
+{
+	if (num < NGROUPS)
+		maxgrplist = num;
+}
+
 /*
  * Returns an auth handle with parameters determined by doing lots of
  * syscalls.
@@ -202,6 +216,8 @@ authunix_create_default(void)
 	gid = getegid();
 	if ((len = getgroups(NGRPS, gids)) < 0)
 		abort();
+	if (len > maxgrplist)
+		len = maxgrplist;
 	/* XXX: interface problem; those should all have been unsigned */
 	return (authunix_create(machname, (int)uid, (int)gid, len,
 	    (int *)gids));

lib/libc/rpc/rpc_clnt_auth.3

@@ -2,15 +2,16 @@
 .\" Copyright 1989 AT&T
 .\" @(#)rpc_clnt_auth 1.4 89/07/20 SMI;
 .\" Copyright (c) 1988 Sun Microsystems, Inc. - All Rights Reserved.
-.\"	$NetBSD: rpc_clnt_auth.3,v 1.6 2003/04/16 13:34:43 wiz Exp $
+.\"	$NetBSD: rpc_clnt_auth.3,v 1.7 2020/10/03 18:31:29 christos Exp $
-.Dd May 7, 1993
+.Dd October 3, 2020
 .Dt RPC_CLNT_AUTH 3
 .Os
 .Sh NAME
 .Nm auth_destroy ,
 .Nm authnone_create ,
 .Nm authsys_create ,
-.Nm authsys_create_default
+.Nm authsys_create_default ,
+.Nm set_rpc_maxgrouplist
 .Nd library routines for client side remote procedure call authentication
 .Sh LIBRARY
 .Lb libc
@@ -24,6 +25,8 @@
 .Fn authsys_create "const char *host" "const uid_t uid" "const gid_t gid" "const int len" "const gid_t *aup_gids"
 .Ft "AUTH *"
 .Fn authsys_create_default "void"
+.Ft "void"
+.Fn set_rpc_maxgrouplist "int num"
 .Sh DESCRIPTION
 These routines are part of the
 RPC library that allows C language programs to make procedure
@@ -90,6 +93,14 @@ refer to a counted array of groups to which the user belongs.
 Call
 .Fn authsys_create
 with the appropriate parameters.
+.Pp
+.It Fn set_rpc_maxgrouplist
+Allow the application to set the maximum size of the group list
+that will be used in
+.Fn authunix_create_default to
+.Fa num .
+Some servers will refuse mounts if the group list is larger than it expects
+(like 8).
 .El
 .Sh SEE ALSO
 .Xr rpc 3 ,