svn commit: r360042 - head/sys/netpfil/pf

[Kristof Provost]

Author: kp
Date: Fri Apr 17 14:35:11 2020
New Revision: 360042
URL: https://svnweb.freebsd.org/changeset/base/360042

Log:
  pf: Do not allow negative ps_len in DIOCGETSTATES
  
  Userspace may pass a negative ps_len value to us, which causes an
  assertion failure in malloc().
  Treat negative values as zero, i.e. return the required size.
  
  Reported-by:	syzbot+53370d9d0358ee2a059a at syzkaller.appspotmail.com
  Reviewed by:	lutz at donnerhacke.de
  MFC after:	1 week
  Differential Revision:	https://reviews.freebsd.org/D24447

Modified:
  head/sys/netpfil/pf/pf_ioctl.c

Modified: head/sys/netpfil/pf/pf_ioctl.c
==============================================================================
--- head/sys/netpfil/pf/pf_ioctl.c	Fri Apr 17 13:50:26 2020	(r360041)
+++ head/sys/netpfil/pf/pf_ioctl.c	Fri Apr 17 14:35:11 2020	(r360042)
@@ -2163,7 +2163,7 @@ relock_DIOCKILLSTATES:
 		struct pfsync_state	*pstore, *p;
 		int i, nr;
 
-		if (ps->ps_len == 0) {
+		if (ps->ps_len <= 0) {
 			nr = uma_zone_get_cur(V_pf_state_z);
 			ps->ps_len = sizeof(struct pfsync_state) * nr;
 			break;