Author: gordon
Date: Wed Mar 7 05:47:48 2018
New Revision: 330565
URL: https://svnweb.freebsd.org/changeset/base/330565
Log:
Port r329561 to stable/10. There were structural changes preventing MFC.
Check packet length to not make an out of bounds access. Also, save ah_nxt
value to use later, since the ah pointer can become invalid.
Reviewed by: ae@
Approved by: so
Security: CVE-2018-6916
Security: FreeBSD-SA-18:01.ipsec
Modified:
stable/10/sys/netipsec/xform_ah.c
Modified: stable/10/sys/netipsec/xform_ah.c
==============================================================================
--- stable/10/sys/netipsec/xform_ah.c Wed Mar 7 04:11:14 2018
(r330564)
+++ stable/10/sys/netipsec/xform_ah.c Wed Mar 7 05:47:48 2018
(r330565)
@@ -599,6 +599,16 @@ ah_input(struct mbuf *m, struct secasvar *sav, int ski
m_freem(m);
return EACCES;
}
+ if (skip + authsize + rplen > m->m_pkthdr.len) {
+ DPRINTF(("%s: bad mbuf length %u (expecting %lu)"
+ " for packet in SA %s/%08lx\n", __func__,
+ m->m_pkthdr.len, (u_long) (skip + authsize + rplen),
+ ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
+ (u_long) ntohl(sav->spi)));
+ AHSTAT_INC(ahs_badauthl);
+ error = EACCES;
+ goto bad;
+ }
AHSTAT_ADD(ahs_ibytes, m->m_pkthdr.len - skip - hl);
/* Get crypto descriptors. */
@@ -664,6 +674,9 @@ ah_input(struct mbuf *m, struct secasvar *sav, int ski
/* Zeroize the authenticator on the packet. */
m_copyback(m, skip + rplen, authsize, ipseczeroes);
+ /* Save ah_nxt, since ah pointer can become invalid after
"massage" */
+ hl = ah->ah_nxt;
+
/* "Massage" the packet headers for crypto processing. */
error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
skip, ahx->type, 0);
@@ -688,7 +701,7 @@ ah_input(struct mbuf *m, struct secasvar *sav, int ski
tc->tc_spi = sav->spi;
tc->tc_dst = sav->sah->saidx.dst;
tc->tc_proto = sav->sah->saidx.proto;
- tc->tc_nxt = ah->ah_nxt;
+ tc->tc_nxt = hl;
tc->tc_protoff = protoff;
tc->tc_skip = skip;
tc->tc_ptr = (caddr_t) mtag; /* Save the mtag we've identified. */
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