svn commit: r343295 - head/sys/netpfil/pf

[Kristof Provost]

Author: kp
Date: Tue Jan 22 02:13:33 2019
New Revision: 343295
URL: https://svnweb.freebsd.org/changeset/base/343295

Log:
  pf: Validate psn_len in DIOCGETSRCNODES
  
  psn_len is controlled by user space, but we allocated memory based on it.
  Check how much memory we might need at most (i.e. how many source nodes we
  have) and limit the allocation to that.
  
  Reported by:	markj
  MFC after:	1 week

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

Modified: head/sys/netpfil/pf/pf_ioctl.c
==============================================================================
--- head/sys/netpfil/pf/pf_ioctl.c	Tue Jan 22 02:04:37 2019	(r343294)
+++ head/sys/netpfil/pf/pf_ioctl.c	Tue Jan 22 02:13:33 2019	(r343295)
@@ -3577,14 +3577,18 @@ DIOCCHANGEADDR_error:
 		struct pf_src_node	*n, *p, *pstore;
 		uint32_t		 i, nr = 0;
 
+		for (i = 0, sh = V_pf_srchash; i <= pf_srchashmask;
+				i++, sh++) {
+			PF_HASHROW_LOCK(sh);
+			LIST_FOREACH(n, &sh->nodes, entry)
+				nr++;
+			PF_HASHROW_UNLOCK(sh);
+		}
+
+		psn->psn_len = min(psn->psn_len,
+		    sizeof(struct pf_src_node) * nr);
+
 		if (psn->psn_len == 0) {
-			for (i = 0, sh = V_pf_srchash; i <= pf_srchashmask;
-			    i++, sh++) {
-				PF_HASHROW_LOCK(sh);
-				LIST_FOREACH(n, &sh->nodes, entry)
-					nr++;
-				PF_HASHROW_UNLOCK(sh);
-			}
 			psn->psn_len = sizeof(struct pf_src_node) * nr;
 			break;
 		}