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oncp.c
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oncp.c
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/*
* OpenConnect (SSL + DTLS) VPN client
*
* Copyright © 2008-2015 Intel Corporation.
*
* Author: David Woodhouse <[email protected]>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* version 2.1, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*/
/*
* Grateful thanks to Tiebing Zhang, who did much of the hard work
* of analysing and decoding the protocol.
*/
#include <config.h>
#include "openconnect-internal.h"
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <time.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
static void buf_append_tlv(struct oc_text_buf *buf, uint16_t val, uint32_t len, void *data)
{
unsigned char b[6];
store_be16(b, val);
store_be32(b + 2, len);
buf_append_bytes(buf, b, 6);
if (len)
buf_append_bytes(buf, data, len);
}
static void buf_append_tlv_be32(struct oc_text_buf *buf, uint16_t val, uint32_t data)
{
unsigned char d[4];
store_be32(d, data);
buf_append_tlv(buf, val, 4, d);
}
static const char authpkt_head[] = { 0x00, 0x04, 0x00, 0x00, 0x00 };
static const char authpkt_tail[] = { 0xbb, 0x01, 0x00, 0x00, 0x00, 0x00 };
#define GRP_ATTR(g, a) (((g) << 16) | (a))
static int process_attr(struct openconnect_info *vpninfo,
struct oc_vpn_option **new_opts, struct oc_ip_info *new_ip_info,
int group, int attr, unsigned char *data, int attrlen)
{
char buf[80];
int i;
switch(GRP_ATTR(group, attr)) {
case GRP_ATTR(6, 2):
if (attrlen != 4) {
badlen:
vpn_progress(vpninfo, PRG_ERR,
_("Unexpected length %d for TLV %d/%d\n"),
attrlen, group, attr);
return -EINVAL;
}
new_ip_info->mtu = load_be32(data);
vpn_progress(vpninfo, PRG_DEBUG,
_("Received MTU %d from server\n"),
new_ip_info->mtu);
break;
case GRP_ATTR(2, 1):
if (attrlen != 4)
goto badlen;
snprintf(buf, sizeof(buf), "%d.%d.%d.%d", data[0], data[1], data[2], data[3]);
vpn_progress(vpninfo, PRG_DEBUG, _("Received DNS server %s\n"), buf);
for (i = 0; i < 3; i++) {
if (!new_ip_info->dns[i]) {
new_ip_info->dns[i] = add_option_dup(new_opts, "DNS", buf, -1);
break;
}
}
break;
case GRP_ATTR(2, 2):
vpn_progress(vpninfo, PRG_DEBUG, _("Received DNS search domain %.*s\n"),
attrlen, (char *)data);
new_ip_info->domain = add_option_dup(new_opts, "search", (char *)data, attrlen);
break;
case GRP_ATTR(1, 1):
if (attrlen != 4)
goto badlen;
snprintf(buf, sizeof(buf), "%d.%d.%d.%d", data[0], data[1], data[2], data[3]);
vpn_progress(vpninfo, PRG_DEBUG, _("Received internal IP address %s\n"), buf);
new_ip_info->addr = add_option_dup(new_opts, "ipaddr", buf, -1);
break;
case GRP_ATTR(1, 2):
if (attrlen != 4)
goto badlen;
snprintf(buf, sizeof(buf), "%d.%d.%d.%d", data[0], data[1], data[2], data[3]);
vpn_progress(vpninfo, PRG_DEBUG, _("Received netmask %s\n"), buf);
new_ip_info->netmask = add_option_dup(new_opts, "netmask", buf, -1);
break;
case GRP_ATTR(1, 3):
if (attrlen != 4)
goto badlen;
snprintf(buf, sizeof(buf), "%d.%d.%d.%d", data[0], data[1], data[2], data[3]);
vpn_progress(vpninfo, PRG_DEBUG, _("Received internal gateway address %s\n"), buf);
/* Hm, what are we supposed to do with this? It's a tunnel;
having a gateway is meaningless. */
add_option_dup(new_opts, "ipaddr", buf, -1);
break;
case GRP_ATTR(3, 3): {
struct oc_split_include *inc;
if (attrlen != 8)
goto badlen;
snprintf(buf, sizeof(buf), "%d.%d.%d.%d/%d.%d.%d.%d",
data[0], data[1], data[2], data[3],
data[4], data[5], data[6], data[7]);
vpn_progress(vpninfo, PRG_DEBUG, _("Received split include route %s\n"), buf);
inc = malloc(sizeof(*inc));
if (inc) {
inc->route = add_option_dup(new_opts, "split-include", buf, -1);
if (inc->route) {
inc->next = new_ip_info->split_includes;
new_ip_info->split_includes = inc;
} else
free(inc);
}
break;
}
case GRP_ATTR(3, 4): {
struct oc_split_include *exc;
if (attrlen != 8)
goto badlen;
snprintf(buf, sizeof(buf), "%d.%d.%d.%d/%d.%d.%d.%d",
data[0], data[1], data[2], data[3],
data[4], data[5], data[6], data[7]);
vpn_progress(vpninfo, PRG_DEBUG, _("Received split exclude route %s\n"), buf);
exc = malloc(sizeof(*exc));
if (exc) {
exc->route = add_option_dup(new_opts, "split-exclude", buf, -1);
if (exc->route) {
exc->next = new_ip_info->split_excludes;
new_ip_info->split_excludes = exc;
} else
free(exc);
}
break;
}
case GRP_ATTR(4, 1):
if (attrlen != 4)
goto badlen;
snprintf(buf, sizeof(buf), "%d.%d.%d.%d", data[0], data[1], data[2], data[3]);
vpn_progress(vpninfo, PRG_DEBUG, _("Received WINS server %s\n"), buf);
for (i = 0; i < 3; i++) {
if (!new_ip_info->nbns[i]) {
new_ip_info->nbns[i] = add_option_dup(new_opts, "WINS", buf, -1);
break;
}
}
break;
case GRP_ATTR(8, 1): {
const char *enctype;
if (attrlen != 1)
goto badlen;
if (data[0] == ENC_AES_128_CBC) {
enctype = "AES-128";
vpninfo->enc_key_len = 16;
} else if (data[0] == ENC_AES_256_CBC) {
enctype = "AES-256";
vpninfo->enc_key_len = 32;
} else
enctype = "unknown";
vpn_progress(vpninfo, PRG_DEBUG, _("ESP encryption: 0x%02x (%s)\n"),
data[0], enctype);
vpninfo->esp_enc = data[0];
break;
}
case GRP_ATTR(8, 2): {
const char *mactype;
if (attrlen != 1)
goto badlen;
if (data[0] == HMAC_MD5) {
mactype = "MD5";
vpninfo->hmac_key_len = 16;
} else if (data[0] == HMAC_SHA1) {
mactype = "SHA1";
vpninfo->hmac_key_len = 20;
} else
mactype = "unknown";
vpn_progress(vpninfo, PRG_DEBUG, _("ESP HMAC: 0x%02x (%s)\n"),
data[0], mactype);
vpninfo->esp_hmac = data[0];
break;
}
case GRP_ATTR(8, 3):
if (attrlen != 1)
goto badlen;
vpninfo->esp_compr = data[0];
vpninfo->dtls_compr = data[0] ? COMPR_LZO : 0;
vpn_progress(vpninfo, PRG_DEBUG, _("ESP compression: %d\n"), data[0]);
break;
case GRP_ATTR(8, 4):
if (attrlen != 2)
goto badlen;
i = load_be16(data);
udp_sockaddr(vpninfo, i);
vpn_progress(vpninfo, PRG_DEBUG, _("ESP port: %d\n"), i);
break;
case GRP_ATTR(8, 5):
if (attrlen != 4)
goto badlen;
vpninfo->esp_lifetime_bytes = load_be32(data);
vpn_progress(vpninfo, PRG_DEBUG, _("ESP key lifetime: %u bytes\n"),
vpninfo->esp_lifetime_bytes);
break;
case GRP_ATTR(8, 6):
if (attrlen != 4)
goto badlen;
vpninfo->esp_lifetime_seconds = load_be32(data);
vpn_progress(vpninfo, PRG_DEBUG, _("ESP key lifetime: %u seconds\n"),
vpninfo->esp_lifetime_seconds);
break;
case GRP_ATTR(8, 9):
if (attrlen != 4)
goto badlen;
vpninfo->esp_ssl_fallback = load_be32(data);
vpn_progress(vpninfo, PRG_DEBUG, _("ESP to SSL fallback: %u seconds\n"),
vpninfo->esp_ssl_fallback);
break;
case GRP_ATTR(8, 10):
if (attrlen != 4)
goto badlen;
vpninfo->esp_replay_protect = load_be32(data);
vpn_progress(vpninfo, PRG_DEBUG, _("ESP replay protection: %d\n"),
load_be32(data));
break;
case GRP_ATTR(7, 1):
if (attrlen != 4)
goto badlen;
memcpy(&vpninfo->esp_out.spi, data, 4);
vpn_progress(vpninfo, PRG_DEBUG, _("ESP SPI (outbound): %x\n"),
load_be32(data));
break;
case GRP_ATTR(7, 2):
if (attrlen != 0x40)
goto badlen;
/* data contains enc_key and hmac_key concatenated */
memcpy(vpninfo->esp_out.enc_key, data, 0x40);
vpn_progress(vpninfo, PRG_DEBUG, _("%d bytes of ESP secrets\n"),
attrlen);
break;
default:
buf[0] = 0;
for (i=0; i < 16 && i < attrlen; i++)
sprintf(buf + strlen(buf), " %02x", data[i]);
if (attrlen > 16)
sprintf(buf + strlen(buf), "...");
vpn_progress(vpninfo, PRG_DEBUG,
_("Unknown TLV group %d attr %d len %d:%s\n"),
group, attr, attrlen, buf);
}
return 0;
}
static void put_len16(struct oc_text_buf *buf, int where)
{
int len = buf->pos - where;
store_be16(buf->data + where - 2, len);
}
static void put_len32(struct oc_text_buf *buf, int where)
{
int len = buf->pos - where;
store_be32(buf->data + where - 4, len);
}
/* We don't know what these are so just hope they never change */
static const unsigned char kmp_head[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
static const unsigned char kmp_tail[] = { 0x01, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00 };
static const unsigned char kmp_tail_out[] = { 0x01, 0x00, 0x00, 0x00, 0x01,
0x00, 0x00, 0x00, 0x00, 0x00 };
static const unsigned char data_hdr[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x01, 0x2c, 0x01, 0x00, 0x00, 0x00, /* KMP message ID = 300 (0x12c) */
0x01, 0x00, 0x00, 0x00, 0x00, 0x00 };
#ifdef HAVE_ESP
static const unsigned char esp_kmp_hdr[] = {
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x2e, /* KMP message ID = 302 (0x12e) */
0x01, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, /* KMP header */
0x00, 0x56, /* KMP length */
0x00, 0x07, 0x00, 0x00, 0x00, 0x50, /* TLV group 7 */
0x00, 0x01, 0x00, 0x00, 0x00, 0x04, /* Attr 1 (SPI) */
};
/* Followed by 4 bytes of SPI */
static const unsigned char esp_kmp_part2[] = {
0x00, 0x02, 0x00, 0x00, 0x00, 0x40, /* Attr 2 (secrets) */
};
/* And now 0x40 bytes of random secret for encryption and HMAC key */
static const struct pkt esp_enable_pkt = {
.next = NULL,
{ .oncp = { .rec = { 0x21, 0x00 },
.kmp = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x2f, /* KMP message ID = 303 (0x12f), len = 13 (0x0d) */
0x01, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x0d } }
},
.data = {
0x00, 0x06, 0x00, 0x00, 0x00, 0x07, /* Group 6, len 7 */
0x00, 0x01, 0x00, 0x00, 0x00, 0x01, /* Attr 1, len 1 */
0x01 /* Value (1 to enable ESP, 0 to disable) */
},
.len = 13
};
static int queue_esp_control(struct openconnect_info *vpninfo, int enable)
{
struct pkt *new = alloc_pkt(vpninfo, esp_enable_pkt.len);
if (!new)
return -ENOMEM;
new->oncp = esp_enable_pkt.oncp;
new->len = esp_enable_pkt.len;
memcpy(new->data, esp_enable_pkt.data, esp_enable_pkt.len);
new->data[12] = enable;
queue_packet(&vpninfo->tcp_control_queue, new);
return 0;
}
#endif /* HAVE_ESP */
static int check_kmp_header(struct openconnect_info *vpninfo, unsigned char *bytes, int pktlen)
{
if (pktlen < 20 || memcmp(bytes, kmp_head, sizeof(kmp_head)) ||
memcmp(bytes + 8, kmp_tail, sizeof(kmp_tail))) {
vpn_progress(vpninfo, PRG_ERR,
_("Failed to parse KMP header\n"));
return -EINVAL;
}
return load_be16(bytes + 6);
}
static int parse_conf_pkt(struct openconnect_info *vpninfo, unsigned char *bytes, int pktlen, int kmp)
{
int kmplen, kmpend, grouplen, groupend, group, attr, attrlen;
int ofs = 0;
int split_enc_hmac_keys = 0;
struct oc_vpn_option *new_opts = NULL;
struct oc_ip_info new_ip_info = {};
kmplen = load_be16(bytes + ofs + 18);
kmpend = ofs + kmplen;
if (kmpend > pktlen) {
eparse:
vpn_progress(vpninfo, PRG_ERR,
_("Failed to parse KMP message\n"));
dump_buf_hex(vpninfo, PRG_ERR, '<', bytes, pktlen);
einval:
free_optlist(new_opts);
free_split_routes(&new_ip_info);
return -EINVAL;
}
vpn_progress(vpninfo, PRG_DEBUG,
_("Got KMP message %d of size %d\n"),
kmp, kmplen);
ofs += 0x14;
while (ofs < kmpend) {
if (ofs + 6 > kmpend)
goto eparse;
group = load_be16(bytes + ofs);
grouplen = load_be32(bytes + ofs + 2);
ofs += 6;
groupend = ofs + grouplen;
if (groupend > pktlen)
goto eparse;
if (kmp == 302 && group != 7 && group != 8) {
vpn_progress(vpninfo, PRG_ERR,
_("Received non-ESP TLVs (group %d) in ESP negotiation KMP\n"),
group);
goto einval;
}
while (ofs < groupend) {
if (ofs + 6 > groupend)
goto eparse;
attr = load_be16(bytes + ofs);
attrlen = load_be32(bytes + ofs + 2);
ofs += 6;
if (attrlen + ofs > groupend)
goto eparse;
if (process_attr(vpninfo, &new_opts, &new_ip_info,
group, attr, bytes + ofs, attrlen))
goto eparse;
if (GRP_ATTR(group, attr)==GRP_ATTR(7, 2))
split_enc_hmac_keys = 1;
ofs += attrlen;
}
}
/* The encryption and HMAC keys are sent concatenated together in a block of 0x40 bytes;
we can't split them apart until we know how long the encryption key is. */
if (split_enc_hmac_keys)
memcpy(vpninfo->esp_out.hmac_key, vpninfo->esp_out.enc_key + vpninfo->enc_key_len, vpninfo->hmac_key_len);
int ret = install_vpn_opts(vpninfo, new_opts, &new_ip_info);
if (ret) {
free_optlist(new_opts);
free_split_routes(&new_ip_info);
return ret;
}
return 0;
}
int oncp_connect(struct openconnect_info *vpninfo)
{
int ret, len, kmp, kmplen, group, check_len;
struct oc_text_buf *reqbuf;
unsigned char bytes[65536];
if (!vpninfo->cookies) {
/* XX: This will happen if authentication was separate/external */
ret = internal_split_cookies(vpninfo, 0, "DSID");
if (ret)
return ret;
}
ret = openconnect_open_https(vpninfo);
if (ret)
return ret;
reqbuf = buf_alloc();
buf_append(reqbuf, "POST /dana/js?prot=1&svc=4 HTTP/1.1\r\n");
/* The TLS socket actually remains open for use by the oNCP
tunnel, but the "Connection: close" header is nevertheless
required here. It appears to signal to the server to stop
treating this as an HTTP connection and to start treating
it as an oNCP connection.
*/
buf_append(reqbuf, "Connection: close\r\n");
oncp_common_headers(vpninfo, reqbuf);
buf_append(reqbuf, "Content-Length: 256\r\n");
buf_append(reqbuf, "\r\n");
if (buf_error(reqbuf)) {
vpn_progress(vpninfo, PRG_ERR,
_("Error creating oNCP negotiation request\n"));
ret = buf_error(reqbuf);
goto out;
}
if (vpninfo->dump_http_traffic)
dump_buf(vpninfo, '>', reqbuf->data);
ret = vpninfo->ssl_write(vpninfo, reqbuf->data, reqbuf->pos);
if (ret < 0)
goto out;
ret = process_http_response(vpninfo, 1, NULL, reqbuf);
if (ret < 0)
goto out;
if (ret != 200) {
vpn_progress(vpninfo, PRG_ERR,
_("Unexpected %d result from server\n"),
ret);
ret = ((ret >= 400 && ret <= 499) || ret == 302) ? -EPERM : -EINVAL;
goto out;
}
/* This is probably some kind of vestigial authentication packet, although
* it's mostly obsolete now that the authentication is really done over
* HTTP. We only send the hostname. */
buf_truncate(reqbuf);
buf_append_le16(reqbuf, sizeof(authpkt_head) + 2 +
strlen(vpninfo->localname) + sizeof(authpkt_tail));
buf_append_bytes(reqbuf, authpkt_head, sizeof(authpkt_head));
buf_append_le16(reqbuf, strlen(vpninfo->localname));
buf_append(reqbuf, "%s", vpninfo->localname);
buf_append_bytes(reqbuf, authpkt_tail, sizeof(authpkt_tail));
if (buf_error(reqbuf)) {
vpn_progress(vpninfo, PRG_ERR,
_("Error creating oNCP negotiation request\n"));
ret = buf_error(reqbuf);
goto out;
}
dump_buf_hex(vpninfo, PRG_DEBUG, '>', (void *)reqbuf->data, reqbuf->pos);
ret = vpninfo->ssl_write(vpninfo, reqbuf->data, reqbuf->pos);
if (ret != reqbuf->pos) {
if (ret >= 0) {
vpn_progress(vpninfo, PRG_ERR,
_("Short write in oNCP negotiation\n"));
ret = -EIO;
}
goto out;
}
/* Now we expect a three-byte response with what's presumably an
error code */
ret = vpninfo->ssl_read(vpninfo, (void *)bytes, 3);
check_len = load_le16(bytes);
if (ret < 0)
goto out;
vpn_progress(vpninfo, PRG_TRACE,
_("Read %d bytes of SSL record\n"), ret);
dump_buf_hex(vpninfo, PRG_TRACE, '<', (void *)bytes, ret);
if (ret != 3 || check_len < 1) {
vpn_progress(vpninfo, PRG_ERR,
_("Unexpected response of size %d after hostname packet\n"),
ret);
ret = -EINVAL;
goto out;
}
if (bytes[2]) {
vpn_progress(vpninfo, PRG_ERR,
_("Server response to hostname packet is error 0x%02x\n"),
bytes[2]);
if (bytes[2] == 0x08)
vpn_progress(vpninfo, PRG_ERR,
_("This seems to indicate that the server has disabled support for\n"
"Juniper's older oNCP protocol, and only allows connections using\n"
"the newer Junos Pulse protocol. This version of OpenConnect has\n"
"EXPERIMENTAL support for Pulse using --prot=pulse\n"));
ret = -EINVAL;
goto out;
}
/* And then a KMP message 301 with the IP configuration.
* Sometimes this arrives as a separate SSL record (with its own
* 2-byte length prefix), and sometimes concatenated with the
* previous 3-byte response).
*/
if (check_len == 1) {
len = vpninfo->ssl_read(vpninfo, (void *)bytes, sizeof(bytes));
if (len < 0) {
ret = len;
goto out;
}
check_len = load_le16(bytes);
} else {
len = vpninfo->ssl_read(vpninfo, (void *)(bytes+2), sizeof(bytes)-2);
if (len < 0) {
ret = len;
goto out;
}
len += 2;
check_len--;
}
/* Now there is a record of size 'check_len', of which we have the
* first (len-2) bytes starting at bytes[2]. */
vpn_progress(vpninfo, PRG_TRACE,
_("Read %d bytes of SSL record\n"), len);
if (len < 0x16 || check_len + 2 != len) {
vpn_progress(vpninfo, PRG_ERR,
_("Invalid packet waiting for KMP 301\n"));
dump_buf_hex(vpninfo, PRG_ERR, '<', bytes, len);
ret = -EINVAL;
goto out;
}
if (vpninfo->dump_http_traffic)
dump_buf_hex(vpninfo, PRG_TRACE, '<', bytes + 2, len - 2);
ret = check_kmp_header(vpninfo, bytes + 2, len - 2);
if (ret < 0)
goto out;
/* We expect KMP message 301 here */
if (ret != 301) {
vpn_progress(vpninfo, PRG_ERR,
_("Expected KMP message 301 from server but got %d\n"),
ret);
ret = -EINVAL;
goto out;
}
kmplen = load_be16(bytes + 20);
if (kmplen + 2 >= sizeof(bytes)) {
vpn_progress(vpninfo, PRG_ERR,
_("KMP message 301 from server too large (%d bytes)\n"),
kmplen);
ret = -EINVAL;
goto out;
}
vpn_progress(vpninfo, PRG_TRACE,
_("Got KMP message 301 of length %d\n"), kmplen);
while (kmplen + 22 > len) {
char l[2];
int thislen;
if (vpninfo->ssl_read(vpninfo, (void *)l, 2) != 2) {
vpn_progress(vpninfo, PRG_ERR,
_("Failed to read continuation record length\n"));
ret = -EINVAL;
goto out;
}
if (load_le16(l) + len > kmplen + 22) {
vpn_progress(vpninfo, PRG_ERR,
_("Record of additional %d bytes too large; would make %d\n"),
load_le16(l), len + load_le16(l));
ret = -EINVAL;
goto out;
}
thislen = vpninfo->ssl_read(vpninfo, (void *)(bytes + len), load_le16(l));
if (thislen != load_le16(l)) {
vpn_progress(vpninfo, PRG_ERR,
_("Failed to read continuation record of length %d\n"),
load_le16(l));
ret = -EINVAL;
goto out;
}
/*
* Sometimes the server throws IP packets into the *middle* of the config!
* https://gitlab.com/openconnect/openconnect/-/issues/562#note_1357470906
*
* We can't use check_kmp_header() because the byte after the KMP type is
* 0x00 not 0x01 which kmp_tail expects. So we do the check manually...
*
* This check may have false positives, if this genuinely *is* the end of
* the config packet but just happens to *look* like KMP300 with a Legacy
* IP packet in it. And false negatives, if there's more than one KMP300
* in the SSL record — which we know *can* happen later. We also know that
* KMP300s can be split across multiple records. So if we get this, then
* another record which doesn't have a KMP header... how are we even
* supposed to guess which one that next record is supposed to complete?
*
* We *could* collect all the frames into a list and then each time we
* get a new frame, attempt to find a set of frames which add up to the
* correct size and see if they parse sanely. But let's try this for now.
*/
if (thislen >= 21 && !memcmp(bytes + len, kmp_head, sizeof(kmp_head)) &&
!bytes[len + 8] && !memcmp(bytes + len + 9, kmp_tail + 1, sizeof(kmp_tail) - 1) &&
load_be16(bytes + len + 6) == 300 && load_be16(bytes + len + 18) + 20 == thislen &&
bytes[len + 20] == 0x45 /* Only Legacy IP over oNCP anyway */) {
vpn_progress(vpninfo, PRG_INFO,
_("Discarding Legacy IP frame in the middle of oNCP config\n"));
continue;
}
vpn_progress(vpninfo, PRG_TRACE,
_("Read additional %d bytes of KMP 301 message\n"),
thislen);
if (vpninfo->dump_http_traffic)
dump_buf_hex(vpninfo, PRG_TRACE, '<', bytes + len, thislen);
len += thislen;
}
ret = parse_conf_pkt(vpninfo, bytes + 2, len - 2, ret);
if (ret)
goto out;
buf_truncate(reqbuf);
buf_append_le16(reqbuf, 0); /* Length. We'll fix it later. */
buf_append_bytes(reqbuf, kmp_head, sizeof(kmp_head));
buf_append_be16(reqbuf, 303); /* KMP message 303 */
buf_append_bytes(reqbuf, kmp_tail_out, sizeof(kmp_tail_out));
buf_append_be16(reqbuf, 0); /* KMP message length */
kmp = reqbuf->pos;
buf_append_tlv(reqbuf, 6, 0, NULL); /* TLV group 6 */
group = reqbuf->pos;
buf_append_tlv_be32(reqbuf, 2, vpninfo->ip_info.mtu);
if (buf_error(reqbuf)) {
vpn_progress(vpninfo, PRG_ERR,
_("Error creating oNCP negotiation request\n"));
ret = buf_error(reqbuf);
goto out;
}
put_len32(reqbuf, group);
put_len16(reqbuf, kmp);
#ifdef HAVE_ESP
if (!openconnect_setup_esp_keys(vpninfo, 1)) {
struct esp *esp = &vpninfo->esp_in[vpninfo->current_esp_in];
/* Since we'll want to do this in the oncp_mainloop too, where it's easier
* *not* to have an oc_text_buf and build it up manually, and since it's
* all fixed size and fairly simple anyway, just hard-code the packet */
buf_append_bytes(reqbuf, esp_kmp_hdr, sizeof(esp_kmp_hdr));
buf_append_bytes(reqbuf, &esp->spi, sizeof(esp->spi));
buf_append_bytes(reqbuf, esp_kmp_part2, sizeof(esp_kmp_part2));
buf_append_bytes(reqbuf, &esp->enc_key, vpninfo->enc_key_len);
buf_append_bytes(reqbuf, &esp->hmac_key, 0x40 - vpninfo->enc_key_len);
if (buf_error(reqbuf)) {
vpn_progress(vpninfo, PRG_ERR,
_("Error negotiating ESP keys\n"));
ret = buf_error(reqbuf);
goto out;
}
}
#endif
/* Length at the start of the packet is little-endian */
store_le16(reqbuf->data, reqbuf->pos - 2);
vpn_progress(vpninfo, PRG_DEBUG, _("oNCP negotiation request outgoing:\n"));
dump_buf_hex(vpninfo, PRG_DEBUG, '>', (void *)reqbuf->data, reqbuf->pos);
ret = vpninfo->ssl_write(vpninfo, reqbuf->data, reqbuf->pos);
if (ret != reqbuf->pos) {
if (ret >= 0) {
vpn_progress(vpninfo, PRG_ERR,
_("Short write in oNCP negotiation\n"));
ret = -EIO;
}
goto out;
}
ret = 0;
out:
if (ret)
openconnect_close_https(vpninfo, 0);
else {
monitor_fd_new(vpninfo, ssl);
monitor_read_fd(vpninfo, ssl);
monitor_except_fd(vpninfo, ssl);
}
buf_free(reqbuf);
vpninfo->partial_rec_size = 0;
free_pkt(vpninfo, vpninfo->cstp_pkt);
vpninfo->cstp_pkt = NULL;
return ret;
}
static int oncp_receive_espkeys(struct openconnect_info *vpninfo, int len)
{
#ifdef HAVE_ESP
int ret;
ret = parse_conf_pkt(vpninfo, vpninfo->cstp_pkt->oncp.kmp, len + 20, 301);
if (!ret)
ret = openconnect_setup_esp_keys(vpninfo, 1);
if (!ret) {
struct esp *esp = &vpninfo->esp_in[vpninfo->current_esp_in];
unsigned char *p = vpninfo->cstp_pkt->oncp.kmp;
memcpy(p, esp_kmp_hdr, sizeof(esp_kmp_hdr));
p += sizeof(esp_kmp_hdr);
memcpy(p, &esp->spi, sizeof(esp->spi));
p += sizeof(esp->spi);
memcpy(p, esp_kmp_part2, sizeof(esp_kmp_part2));
p += sizeof(esp_kmp_part2);
memcpy(p, esp->enc_key, vpninfo->enc_key_len);
memcpy(p+vpninfo->enc_key_len, esp->hmac_key, 0x40 - vpninfo->enc_key_len);
p += 0x40;
vpninfo->cstp_pkt->len = p - vpninfo->cstp_pkt->data;
store_le16(vpninfo->cstp_pkt->oncp.rec,
(p - vpninfo->cstp_pkt->oncp.kmp));
queue_packet(&vpninfo->tcp_control_queue, vpninfo->cstp_pkt);
vpninfo->cstp_pkt = NULL;
print_esp_keys(vpninfo, _("new incoming"), esp);
print_esp_keys(vpninfo, _("new outgoing"), &vpninfo->esp_out);
}
return ret;
#else
vpn_progress(vpninfo, PRG_DEBUG,
_("Ignoring ESP keys since ESP support not available in this build\n"));
return 0;
#endif
}
static int oncp_record_read(struct openconnect_info *vpninfo, void *buf, int len)
{
int ret;
if (!vpninfo->partial_rec_size) {
unsigned char lenbuf[2];
ret = ssl_nonblock_read(vpninfo, 0, lenbuf, 2);
if (ret <= 0)
return ret;
if (ret == 1) {
/* Surely at least *this* never happens? The two length bytes
* of the oNCP record being split across multiple SSL records */
vpn_progress(vpninfo, PRG_ERR,
_("Read only 1 byte of oNCP length field\n"));
return -EIO;
}
vpninfo->partial_rec_size = load_le16(lenbuf);
if (!vpninfo->partial_rec_size) {
ret = ssl_nonblock_read(vpninfo, 0, lenbuf, 1);
if (ret == 1) {
if (lenbuf[0] == 1) {
vpn_progress(vpninfo, PRG_ERR,
_("Server terminated connection (session expired)\n"));
vpninfo->quit_reason = "VPN session expired";
} else if (lenbuf[0] == 8) {
vpn_progress(vpninfo, PRG_ERR,
_("Server terminated connection (idle timeout)\n"));
vpninfo->quit_reason = "Idle timeout";
} else {
vpn_progress(vpninfo, PRG_ERR,
_("Server terminated connection (reason: %d)\n"),
lenbuf[0]);
vpninfo->quit_reason = "Server terminated connection";
}
return -EPIPE;
} else {
vpn_progress(vpninfo, PRG_ERR,
_("Server sent zero-length oNCP record\n"));
vpninfo->quit_reason = "Zero-length oNCP record";
return -EIO;
}
}
}
if (len > vpninfo->partial_rec_size)
len = vpninfo->partial_rec_size;
ret = ssl_nonblock_read(vpninfo, 0, buf, len);
if (ret > 0)
vpninfo->partial_rec_size -= ret;
return ret;
}
int oncp_mainloop(struct openconnect_info *vpninfo, int *timeout, int readable)
{
int ret;
int work_done = 0;
/* Periodic TNCC */
if (trojan_check_deadline(vpninfo, timeout)) {
oncp_send_tncc_command(vpninfo, 0);
return 1;
}
if (vpninfo->ssl_fd == -1)
goto do_reconnect;
/* FIXME: The poll() handling here is fairly simplistic. Actually,
if the SSL connection stalls it could return a WANT_WRITE error
on _either_ of the SSL_read() or SSL_write() calls. In that case,
we should probably remove POLLIN from the events we're looking for,
and add POLLOUT. As it is, though, it'll just chew CPU time in that
fairly unlikely situation, until the write backlog clears. */
while (readable) {
int len, kmp, kmplen, iplen;
/* Some servers send us packets that are larger than
negotiated MTU. We reserve some extra space to
handle that */
int receive_mtu = MAX(16384, vpninfo->ip_info.mtu);
len = receive_mtu + vpninfo->pkt_trailer;
if (!vpninfo->cstp_pkt) {
vpninfo->cstp_pkt = alloc_pkt(vpninfo, len);
if (!vpninfo->cstp_pkt) {
vpn_progress(vpninfo, PRG_ERR, _("Allocation failed\n"));
break;
}
vpninfo->cstp_pkt->len = 0;
}
/*
* This protocol is horrid. There are encapsulations within
* encapsulations within encapsulations. Some of them entirely
* gratuitous.
*
* First there's the SSL records which are a natural part of
* using TLS as a transport. They appear to make no use of the
* packetisation which these provide.
*
* Then within the TLS data stream there are "records" preceded
* by a 16-bit little-endian length. It's not clear what these
* records represent; they appear to be entirely gratuitous and
* just need to be discarded. A record boundary sometimes falls
* right in the middle of a data packet; there's no apparent
* logic to it.
*
* Then there are the KMP packets themselves, each of which has
* a length field of its own. There can be multiple KMP packets
* in each of the above-mention "records", and as noted there
* even be *partial* KMP packets in each record.
*
* Finally, a KMP data packet may actually contain multiple IP
* packets, which need to be split apart by using the length
* field in the IP header. This is Legacy IP only, never IPv6
* for the Network Connect protocol.
*/
/* Until we pass it up the stack, we use cstp_pkt->len to show
* the amount of data received *including* the KMP header. */
len = oncp_record_read(vpninfo,
vpninfo->cstp_pkt->oncp.kmp + vpninfo->cstp_pkt->len,
receive_mtu + 20 - vpninfo->cstp_pkt->len);
if (!len)
break;
else if (len < 0) {
if (vpninfo->quit_reason)
return len;
goto do_reconnect;
}
vpninfo->cstp_pkt->len += len;
vpninfo->ssl_times.last_rx = time(NULL);
if (vpninfo->cstp_pkt->len < 20)
continue;
next_kmp:
/* Now we have a KMP header. It might already have been there */
kmp = load_be16(vpninfo->cstp_pkt->oncp.kmp + 6);
kmplen = load_be16(vpninfo->cstp_pkt->oncp.kmp + 18);
if (len == vpninfo->cstp_pkt->len)
vpn_progress(vpninfo, PRG_DEBUG, _("Incoming KMP message %d of size %d (got %d)\n"),
kmp, kmplen, vpninfo->cstp_pkt->len - 20);
else
vpn_progress(vpninfo, PRG_DEBUG, _("Continuing to process KMP message %d now size %d (got %d)\n"),
kmp, kmplen, vpninfo->cstp_pkt->len - 20);
switch (kmp) {
case 300:
next_ip:
/* Need at least 6 bytes of payload to check the IP packet length */
if (vpninfo->cstp_pkt->len < 26)
continue;
switch(vpninfo->cstp_pkt->data[0] >> 4) {
case 4:
iplen = load_be16(vpninfo->cstp_pkt->data + 2);
break;
case 6:
iplen = load_be16(vpninfo->cstp_pkt->data + 4) + 40;
break;
default:
badiplen:
vpn_progress(vpninfo, PRG_ERR,
_("Unrecognised data packet\n"));
goto unknown_pkt;
}
if (!iplen || iplen > receive_mtu || iplen > kmplen)
goto badiplen;
if (iplen > vpninfo->cstp_pkt->len - 20)
continue;
work_done = 1;
vpn_progress(vpninfo, PRG_TRACE,
_("Received uncompressed data packet of %d bytes\n"),
iplen);
/* If there's nothing after the IP packet, and it's the last (or
* only) packet in this KMP300 so we don't need to keep the KMP
* header either, then just queue it. */
if (iplen == kmplen && iplen == vpninfo->cstp_pkt->len - 20) {
vpninfo->cstp_pkt->len = iplen;