From 3e3e9b32519a38f9316986b877163d37557b4f70 Mon Sep 17 00:00:00 2001 From: Alberto Gonzalez Iniesta Date: Thu, 22 Jun 2017 17:25:13 +0200 Subject: Import Debian changes 2.3.4-5+deb8u2 openvpn (2.3.4-5+deb8u2) jessie-security; urgency=high * SECURITY UPDATE: authenticated remote DoS vulnerability due to packet ID rollover. CVE-2017-7479. Kudos to Steve Beattie for doing all the backporting work for this patch. - debian/patches/CVE-2017-7479-prereq.patch: merge packet_id_alloc_outgoing() into packet_id_write() - debian/patches/CVE-2017-7479.patch: do not assert when packet ID rollover occurs * SECURITY UPDATE: (Closes: #865480) - CVE-2017-7508.patch. Fix remotely-triggerable ASSERT() on malformed IPv6 packet. - CVE-2017-7520.patch. Prevent two kinds of stack buffer OOB reads and a crash for invalid input data. - CVE-2017-7521.patch. Fix potential double-free in --x509-alt-username. - CVE-2017-7521bis.patch. Fix remote-triggerable memory leaks. --- debian/patches/CVE-2017-7479.patch | 162 +++++++++++++++++++++++++++++++++++++ 1 file changed, 162 insertions(+) create mode 100644 debian/patches/CVE-2017-7479.patch (limited to 'debian/patches/CVE-2017-7479.patch') diff --git a/debian/patches/CVE-2017-7479.patch b/debian/patches/CVE-2017-7479.patch new file mode 100644 index 0000000..5cbc1ee --- /dev/null +++ b/debian/patches/CVE-2017-7479.patch @@ -0,0 +1,162 @@ +From ac08b27cfa693d9be592bb2597c260635aee9e68 Mon Sep 17 00:00:00 2001 +From: Steffan Karger +Date: Tue, 25 Apr 2017 10:00:44 +0200 +Subject: [PATCH 2/2] Drop packets instead of asserting out if packet id rolls + over +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +Previously, if a mode was selected where packet ids are not allowed to roll +over, but renegotiation does not succeed for some reason (e.g. no password +entered in time, certificate expired or a malicious peer that refuses the +renegotiaion on purpose) we would continue to use the old keys. Until the +packet ID would roll over and we would ASSERT() out. + +Given that this can be triggered on purpose by an authenticated peer, this +is a fix for an authenticated remote DoS vulnerability. An attack is +rather inefficient though; a peer would need to get us to send 2^32 +packets (min-size packet is IP+UDP+OPCODE+PID+TAG (no payload), results in +(20+8+1+4+16)×2^32 bytes, or approx. 196 GB). + +Signed-off-by: Steffan Karger + +CVE-2017-7479 + +[Ubuntu note: 2.3.x does not support tlscrypt, so that portion of patch +was dropped; other backporting to 2.3.x]. --sbeattie + +--- + src/openvpn/crypto.c | 25 ++++++++++++++++--------- + src/openvpn/packet_id.c | 22 ++++++++++++++++------ + src/openvpn/packet_id.h | 1 + + src/openvpn/tls_crypt.c | 6 +++++- + tests/unit_tests/openvpn/test_packet_id.c | 11 +++++++++-- + 5 files changed, 47 insertions(+), 18 deletions(-) + +Index: openvpn-2.3.2/src/openvpn/crypto.c +=================================================================== +--- openvpn-2.3.2.orig/src/openvpn/crypto.c ++++ openvpn-2.3.2/src/openvpn/crypto.c +@@ -112,9 +112,13 @@ openvpn_encrypt (struct buffer *buf, str + prng_bytes (iv_buf, iv_size); + + /* Put packet ID in plaintext buffer or IV, depending on cipher mode */ +- if (opt->packet_id) ++ if (opt->packet_id ++ && !packet_id_write (&opt->packet_id->send, buf, ++ opt->flags & CO_PACKET_ID_LONG_FORM, ++ true)) + { +- ASSERT (packet_id_write (&opt->packet_id->send, buf, BOOL_CAST (opt->flags & CO_PACKET_ID_LONG_FORM), true)); ++ msg(D_CRYPT_ERRORS, "ENCRYPT ERROR: packet ID roll over"); ++ goto err; + } + } + else if (mode == OPENVPN_MODE_CFB || mode == OPENVPN_MODE_OFB) +@@ -182,9 +186,12 @@ openvpn_encrypt (struct buffer *buf, str + } + else /* No Encryption */ + { +- if (opt->packet_id) ++ if (opt->packet_id ++ && !packet_id_write (&opt->packet_id->send, buf, ++ opt->flags & CO_PACKET_ID_LONG_FORM, true)) + { +- ASSERT (packet_id_write (&opt->packet_id->send, buf, BOOL_CAST (opt->flags & CO_PACKET_ID_LONG_FORM), true)); ++ msg(D_CRYPT_ERRORS, "ENCRYPT ERROR: packet ID roll over"); ++ goto err; + } + work = *buf; + } +Index: openvpn-2.3.2/src/openvpn/packet_id.c +=================================================================== +--- openvpn-2.3.2.orig/src/openvpn/packet_id.c ++++ openvpn-2.3.2/src/openvpn/packet_id.c +@@ -294,27 +294,37 @@ packet_id_read (struct packet_id_net *pi + return true; + } + +-static void ++static bool + packet_id_send_update(struct packet_id_send *p, bool long_form) + { + if (!p->time) + { + p->time = now; + } +- p->id++; +- if (!p->id) ++ if (p->id == PACKET_ID_MAX) + { +- ASSERT(long_form); ++ /* Packet ID only allowed to roll over if using long form and time has ++ * moved forward since last roll over. ++ */ ++ if (!long_form || now <= p->time) ++ { ++ return false; ++ } + p->time = now; +- p->id = 1; ++ p->id = 0; + } ++ p->id++; ++ return true; + } + + bool + packet_id_write (struct packet_id_send *p, struct buffer *buf, bool long_form, + bool prepend) + { +- packet_id_send_update(p, long_form); ++ if (!packet_id_send_update(p, long_form)) ++ { ++ return false; ++ } + + const packet_id_type net_id = htonpid(p->id); + const net_time_t net_time = htontime(p->time); +Index: openvpn-2.3.2/src/openvpn/packet_id.h +=================================================================== +--- openvpn-2.3.2.orig/src/openvpn/packet_id.h ++++ openvpn-2.3.2/src/openvpn/packet_id.h +@@ -50,6 +50,7 @@ + * to for network transmission. + */ + typedef uint32_t packet_id_type; ++#define PACKET_ID_MAX UINT32_MAX + typedef uint32_t net_time_t; + + /* +Index: openvpn-2.3.2/tests/unit_tests/openvpn/test_packet_id.c +=================================================================== +--- openvpn-2.3.2.orig/tests/unit_tests/openvpn/test_packet_id.c ++++ openvpn-2.3.2/tests/unit_tests/openvpn/test_packet_id.c +@@ -130,8 +130,7 @@ test_packet_id_write_short_wrap(void **s + struct test_packet_id_write_data *data = *state; + + data->pis.id = ~0; +- expect_assert_failure( +- packet_id_write(&data->pis, &data->test_buf, false, false)); ++ assert_false(packet_id_write(&data->pis, &data->test_buf, false, false)); + } + + static void +@@ -140,8 +139,16 @@ test_packet_id_write_long_wrap(void **st + struct test_packet_id_write_data *data = *state; + + data->pis.id = ~0; ++ data->pis.time = 5006; ++ ++ /* Write fails if time did not change */ ++ now = 5006; ++ assert_false(packet_id_write(&data->pis, &data->test_buf, true, false)); ++ ++ /* Write succeeds if time moved forward */ + now = 5010; + assert_true(packet_id_write(&data->pis, &data->test_buf, true, false)); ++ + assert(data->pis.id == 1); + assert(data->pis.time == now); + assert_true(data->test_buf_data.buf_id == htonl(1)); -- cgit v1.2.3