Date: Mon, 19 Feb 2018 11:14:38 +0000 (UTC) From: "Andrey V. Elsukov" <ae@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r329561 - head/sys/netipsec Message-ID: <201802191114.w1JBEchL022617@repo.freebsd.org>
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Author: ae Date: Mon Feb 19 11:14:38 2018 New Revision: 329561 URL: https://svnweb.freebsd.org/changeset/base/329561 Log: Check packet length to do not make out of bounds access. Also save ah_nxt value to use it later, since ah pointer can become invalid. Reported by: Maxime Villard <max at m00nbsd dot net> MFC after: 5 days Modified: head/sys/netipsec/xform_ah.c Modified: head/sys/netipsec/xform_ah.c ============================================================================== --- head/sys/netipsec/xform_ah.c Mon Feb 19 10:59:19 2018 (r329560) +++ head/sys/netipsec/xform_ah.c Mon Feb 19 11:14:38 2018 (r329561) @@ -582,6 +582,16 @@ ah_input(struct mbuf *m, struct secasvar *sav, int ski error = EACCES; goto bad; } + 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. */ @@ -626,6 +636,9 @@ 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); @@ -650,7 +663,7 @@ ah_input(struct mbuf *m, struct secasvar *sav, int ski /* These are passed as-is to the callback. */ xd->sav = sav; - xd->nxt = ah->ah_nxt; + xd->nxt = hl; xd->protoff = protoff; xd->skip = skip; xd->cryptoid = cryptoid;
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