svn commit: r355966 - stable/12/sys/rpc/rpcsec_gss

[Rick Macklem]

Author: rmacklem
Date: Fri Dec 20 22:53:23 2019
New Revision: 355966
URL: https://svnweb.freebsd.org/changeset/base/355966

Log:
  MFC: r355157, r355161
  Add a cap on credential lifetime for Kerberized NFS.
  
  The kernel RPCSEC_GSS code sets the credential (called a client) lifetime
  to the lifetime of the Kerberos ticket, which is typically several hours.
  As such, when a user's credentials change such as being added to a new group,
  it can take several hours for this change to be recognized by the NFS server.
  This patch adds a sysctl called kern.rpc.gss.lifetime_max which can be set
  by a sysadmin to put a cap on the time to expire for the credentials, so that
  a sysadmin can reduce the timeout.
  It also fixes a bug, where time_uptime is added twice when GSS_C_INDEFINITE
  is returned for a lifetime. This has no effect in practice, since Kerberos
  never does this.

Modified:
  stable/12/sys/rpc/rpcsec_gss/svc_rpcsec_gss.c
Directory Properties:
  stable/12/   (props changed)

Modified: stable/12/sys/rpc/rpcsec_gss/svc_rpcsec_gss.c
==============================================================================
--- stable/12/sys/rpc/rpcsec_gss/svc_rpcsec_gss.c	Fri Dec 20 22:12:21 2019	(r355965)
+++ stable/12/sys/rpc/rpcsec_gss/svc_rpcsec_gss.c	Fri Dec 20 22:53:23 2019	(r355966)
@@ -180,6 +180,11 @@ SYSCTL_UINT(_kern_rpc_gss, OID_AUTO, client_max, CTLFL
     &svc_rpc_gss_client_max, 0,
     "Max number of rpc-gss clients");
 
+static u_int svc_rpc_gss_lifetime_max = 0;
+SYSCTL_UINT(_kern_rpc_gss, OID_AUTO, lifetime_max, CTLFLAG_RW,
+    &svc_rpc_gss_lifetime_max, 0,
+    "Maximum lifetime (seconds) of rpc-gss clients");
+
 static u_int svc_rpc_gss_client_count;
 SYSCTL_UINT(_kern_rpc_gss, OID_AUTO, client_count, CTLFLAG_RD,
     &svc_rpc_gss_client_count, 0,
@@ -950,8 +955,15 @@ svc_rpc_gss_accept_sec_context(struct svc_rpc_gss_clie
 		 * that out).
 		 */
 		if (cred_lifetime == GSS_C_INDEFINITE)
-			cred_lifetime = time_uptime + 24*60*60;
+			cred_lifetime = 24*60*60;
 
+		/*
+		 * Cap cred_lifetime if sysctl kern.rpc.gss.lifetime_max is set.
+		 */
+		if (svc_rpc_gss_lifetime_max > 0 && cred_lifetime >
+		    svc_rpc_gss_lifetime_max)
+			cred_lifetime = svc_rpc_gss_lifetime_max;
+		
 		client->cl_expiration = time_uptime + cred_lifetime;
 
 		/*