svn commit: r290360 - stable/10/sys/net

[Andrey V. Elsukov]

Author: ae
Date: Wed Nov  4 10:42:51 2015
New Revision: 290360
URL: https://svnweb.freebsd.org/changeset/base/290360

Log:
  MFC r290116:
    Check the size of data available in mbuf before using it.
  
    PR:		202667

Modified:
  stable/10/sys/net/if_gre.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/sys/net/if_gre.c
==============================================================================
--- stable/10/sys/net/if_gre.c	Wed Nov  4 10:35:10 2015	(r290359)
+++ stable/10/sys/net/if_gre.c	Wed Nov  4 10:42:51 2015	(r290360)
@@ -691,6 +691,14 @@ gre_input(struct mbuf **mp, int *offp, i
 	KASSERT(sc != NULL, ("encap_getarg returned NULL"));
 
 	ifp = GRE2IFP(sc);
+	hlen = *offp + sizeof(struct grehdr) + 4 * sizeof(uint32_t);
+	if (m->m_pkthdr.len < hlen)
+		goto drop;
+	if (m->m_len < hlen) {
+		m = m_pullup(m, hlen);
+		if (m == NULL)
+			goto drop;
+	}
 	gh = (struct grehdr *)mtodo(m, *offp);
 	flags = ntohs(gh->gre_flags);
 	if (flags & ~GRE_FLAGS_MASK)