svn commit: r316538 - stable/11/sys/kern

[Brooks Davis]

Author: brooks
Date: Wed Apr  5 19:15:06 2017
New Revision: 316538
URL: https://svnweb.freebsd.org/changeset/base/316538

Log:
  MFC r316497:
  
  Correct a kernel stack leak in 32-bit compat when vfc_name is short.
  
  Don't zero unused pointer members again.
  
  Per discussion with secteam we are not issuing an advisory for this
  issue as we have no current evidence it leaks exploitable information.
  
  Reviewed by:	rwatson, glebius, delphij
  Sponsored by:	DARPA, AFRL

Modified:
  stable/11/sys/kern/vfs_subr.c
Directory Properties:
  stable/11/   (props changed)

Modified: stable/11/sys/kern/vfs_subr.c
==============================================================================
--- stable/11/sys/kern/vfs_subr.c	Wed Apr  5 18:59:58 2017	(r316537)
+++ stable/11/sys/kern/vfs_subr.c	Wed Apr  5 19:15:06 2017	(r316538)
@@ -3686,12 +3686,11 @@ vfsconf2x32(struct sysctl_req *req, stru
 {
 	struct xvfsconf32 xvfsp;
 
+	bzero(&xvfsp, sizeof(xvfsp));
 	strcpy(xvfsp.vfc_name, vfsp->vfc_name);
 	xvfsp.vfc_typenum = vfsp->vfc_typenum;
 	xvfsp.vfc_refcount = vfsp->vfc_refcount;
 	xvfsp.vfc_flags = vfsp->vfc_flags;
-	xvfsp.vfc_vfsops = 0;
-	xvfsp.vfc_next = 0;
 	return (SYSCTL_OUT(req, &xvfsp, sizeof(xvfsp)));
 }
 #endif