svn commit: r340899 - head/sys/kern

[Mark Johnston]

Author: markj
Date: Sat Nov 24 17:02:31 2018
New Revision: 340899
URL: https://svnweb.freebsd.org/changeset/base/340899

Log:
  Plug some kernel memory disclosures via kevent(2).
  
  The kernel may register for events on behalf of a userspace process,
  in which case it must be careful to zero the kevent struct that will be
  copied out to userspace.
  
  Reviewed by:	kib
  MFC after:	3 days
  Security:	kernel stack memory disclosure
  Sponsored by:	The FreeBSD Foundation
  Differential Revision:	https://reviews.freebsd.org/D18317

Modified:
  head/sys/kern/kern_event.c
  head/sys/kern/vfs_aio.c

Modified: head/sys/kern/kern_event.c
==============================================================================
--- head/sys/kern/kern_event.c	Sat Nov 24 16:58:34 2018	(r340898)
+++ head/sys/kern/kern_event.c	Sat Nov 24 17:02:31 2018	(r340899)
@@ -535,8 +535,9 @@ knote_fork(struct knlist *list, int pid)
 
 	if (list == NULL)
 		return;
-	list->kl_lock(list->kl_lockarg);
 
+	memset(&kev, 0, sizeof(kev));
+	list->kl_lock(list->kl_lockarg);
 	SLIST_FOREACH(kn, &list->kl_list, kn_selnext) {
 		kq = kn->kn_kq;
 		KQ_LOCK(kq);

Modified: head/sys/kern/vfs_aio.c
==============================================================================
--- head/sys/kern/vfs_aio.c	Sat Nov 24 16:58:34 2018	(r340898)
+++ head/sys/kern/vfs_aio.c	Sat Nov 24 17:02:31 2018	(r340899)
@@ -1589,6 +1589,7 @@ aio_aqueue(struct thread *td, struct aiocb *ujob, stru
 		goto aqueue_fail;
 	}
 	kqfd = job->uaiocb.aio_sigevent.sigev_notify_kqueue;
+	memset(&kev, 0, sizeof(kev));
 	kev.ident = (uintptr_t)job->ujob;
 	kev.filter = EVFILT_AIO;
 	kev.flags = EV_ADD | EV_ENABLE | EV_FLAG1 | evflags;
@@ -2155,6 +2156,7 @@ kern_lio_listio(struct thread *td, int mode, struct ai
 		bcopy(sig, &lj->lioj_signal, sizeof(lj->lioj_signal));
 		if (lj->lioj_signal.sigev_notify == SIGEV_KEVENT) {
 			/* Assume only new style KEVENT */
+			memset(&kev, 0, sizeof(kev));
 			kev.filter = EVFILT_LIO;
 			kev.flags = EV_ADD | EV_ENABLE | EV_FLAG1;
 			kev.ident = (uintptr_t)uacb_list; /* something unique */