svn commit: r316497 - head/sys/kern

[Brooks Davis]

Author: brooks
Date: Tue Apr  4 17:32:08 2017
New Revision: 316497
URL: https://svnweb.freebsd.org/changeset/base/316497

Log:
  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
  MFC after:	1 day
  Sponsored by:	DARPA, AFRL
  Differential Revision:	https://reviews.freebsd.org/D10227

Modified:
  head/sys/kern/vfs_subr.c

Modified: head/sys/kern/vfs_subr.c
==============================================================================
--- head/sys/kern/vfs_subr.c	Tue Apr  4 17:18:45 2017	(r316496)
+++ head/sys/kern/vfs_subr.c	Tue Apr  4 17:32:08 2017	(r316497)
@@ -3781,12 +3781,11 @@ 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