svn commit: r296025 - head/sys/netpfil/pf

[Kristof Provost]

Author: kp
Date: Thu Feb 25 07:33:59 2016
New Revision: 296025
URL: https://svnweb.freebsd.org/changeset/base/296025

Log:
  pf: Fix possible out-of-bounds write
  
  In the DIOCRSETADDRS ioctl() handler we allocate a table for struct pfr_addrs,
  which is processed in pfr_set_addrs(). At the users request we also provide
  feedback on the deleted addresses, by storing them after the new list
  ('bcopy(&ad, addr + size + i, sizeof(ad));' in pfr_set_addrs()).
  
  This means we write outside the bounds of the buffer we've just allocated.
  We need to look at pfrio_size2 instead (i.e. the size the user reserved for our
  feedback). That'd allow a malicious user to specify a smaller pfrio_size2 than
  pfrio_size though, in which case we'd still read outside of the allocated
  buffer. Instead we allocate the largest of the two values.
  
  Reported By:	Paul J Murphy <paul at inetstat.net>
  PR:		207463
  MFC after:	5 days
  Differential Revision:	https://reviews.freebsd.org/D5426

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

Modified: head/sys/netpfil/pf/pf_ioctl.c
==============================================================================
--- head/sys/netpfil/pf/pf_ioctl.c	Thu Feb 25 07:03:10 2016	(r296024)
+++ head/sys/netpfil/pf/pf_ioctl.c	Thu Feb 25 07:33:59 2016	(r296025)
@@ -2718,13 +2718,14 @@ DIOCCHANGEADDR_error:
 	case DIOCRSETADDRS: {
 		struct pfioc_table *io = (struct pfioc_table *)addr;
 		struct pfr_addr *pfras;
-		size_t totlen;
+		size_t totlen, count;
 
 		if (io->pfrio_esize != sizeof(struct pfr_addr)) {
 			error = ENODEV;
 			break;
 		}
-		totlen = io->pfrio_size * sizeof(struct pfr_addr);
+		count = max(io->pfrio_size, io->pfrio_size2);
+		totlen = count * sizeof(struct pfr_addr);
 		pfras = malloc(totlen, M_TEMP, M_WAITOK);
 		error = copyin(io->pfrio_buffer, pfras, totlen);
 		if (error) {