/
oncp.c
1340 lines (1175 loc) · 38.3 KB
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/*
* OpenConnect (SSL + DTLS) VPN client
*
* Copyright © 2008-2015 Intel Corporation.
*
* Author: David Woodhouse <dwmw2@infradead.org>
*
* 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.
*/
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/*
* Grateful thanks to Tiebing Zhang, who did much of the hard work
* of analysing and decoding the protocol.
*/
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#include <config.h>
#include <unistd.h>
#include <fcntl.h>
#include <time.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <stdarg.h>
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#include <sys/types.h>
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#include "openconnect-internal.h"
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static int parse_cookie(struct openconnect_info *vpninfo)
{
char *p = vpninfo->cookie;
/* We currenly expect the "cookie" to be contain multiple cookies:
* DSSignInUrl=/; DSID=xxx; DSFirstAccess=xxx; DSLastAccess=xxx
* Process those into vpninfo->cookies unless we already had them
* (in which case they'll may be newer. */
while (p && *p) {
char *semicolon = strchr(p, ';');
char *equals;
if (semicolon)
*semicolon = 0;
equals = strchr(p, '=');
if (!equals) {
vpn_progress(vpninfo, PRG_ERR, _("Invalid cookie '%s'\n"), p);
return -EINVAL;
}
*equals = 0;
http_add_cookie(vpninfo, p, equals+1, 0);
*equals = '=';
p = semicolon;
if (p) {
*p = ';';
p++;
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while (*p && isspace((int)(unsigned char)*p))
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p++;
}
}
return 0;
}
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static void buf_append_be16(struct oc_text_buf *buf, uint16_t val)
{
unsigned char b[2];
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store_be16(b, val);
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buf_append_bytes(buf, b, 2);
}
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static void buf_append_le16(struct oc_text_buf *buf, uint16_t val)
{
unsigned char b[2];
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store_le16(b, val);
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buf_append_bytes(buf, b, 2);
}
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static void buf_append_tlv(struct oc_text_buf *buf, uint16_t val, uint32_t len, void *data)
{
unsigned char b[6];
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store_be16(b, val);
store_be32(b + 2, len);
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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];
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store_be32(d, data);
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buf_append_tlv(buf, val, 4, d);
}
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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))
/* We behave like CSTP — create a linked list in vpninfo->cstp_options
* with the strings containing the information we got from the server,
* and oc_ip_info contains const copies of those pointers. */
static const char *add_option(struct openconnect_info *vpninfo, const char *opt,
const char *val, int val_len)
{
struct oc_vpn_option *new = malloc(sizeof(*new));
if (!new)
return NULL;
new->option = strdup(opt);
if (!new->option) {
free(new);
return NULL;
}
if (val_len >= 0)
new->value = strndup(val, val_len);
else
new->value = strdup(val);
if (!new->value) {
free(new->option);
free(new);
return NULL;
}
new->next = vpninfo->cstp_options;
vpninfo->cstp_options = new;
return new->value;
}
static int process_attr(struct openconnect_info *vpninfo, 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;
}
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vpninfo->ip_info.mtu = load_be32(data);
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vpn_progress(vpninfo, PRG_DEBUG,
_("Received MTU %d from server\n"),
vpninfo->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 (!vpninfo->ip_info.dns[i]) {
vpninfo->ip_info.dns[i] = add_option(vpninfo, "DNS", buf, -1);
break;
}
}
break;
case GRP_ATTR(2, 2):
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vpn_progress(vpninfo, PRG_DEBUG, _("Received DNS search domain %.*s\n"),
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attrlen, (char *)data);
vpninfo->ip_info.domain = add_option(vpninfo, "search", (char *)data, attrlen);
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if (vpninfo->ip_info.domain) {
char *p = (char *)vpninfo->ip_info.domain;
while ((p = strchr(p, ',')))
*p = ' ';
}
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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);
vpninfo->ip_info.addr = add_option(vpninfo, "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);
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vpninfo->ip_info.netmask = add_option(vpninfo, "netmask", buf, -1);
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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(vpninfo, "ipaddr", buf, -1);
break;
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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);
if (!data[4] && !data[5] && !data[6] && !data[7])
break;
inc = malloc(sizeof(*inc));
if (inc) {
inc->route = add_option(vpninfo, "split-include", buf, -1);
if (inc->route) {
inc->next = vpninfo->ip_info.split_includes;
vpninfo->ip_info.split_includes = inc;
} else
free(inc);
}
break;
}
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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);
if (!data[4] && !data[5] && !data[6] && !data[7])
break;
exc = malloc(sizeof(*exc));
if (exc) {
exc->route = add_option(vpninfo, "split-exclude", buf, -1);
if (exc->route) {
exc->next = vpninfo->ip_info.split_excludes;
vpninfo->ip_info.split_excludes = exc;
} else
free(exc);
}
break;
}
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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 (!vpninfo->ip_info.nbns[i]) {
vpninfo->ip_info.nbns[i] = add_option(vpninfo, "WINS", buf, -1);
break;
}
}
break;
case GRP_ATTR(8, 1): {
const char *enctype;
if (attrlen != 1)
goto badlen;
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if (data[0] == ENC_AES_128_CBC) {
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enctype = "AES-128";
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vpninfo->enc_key_len = 16;
} else if (data[0] == ENC_AES_256_CBC) {
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enctype = "AES-256";
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vpninfo->enc_key_len = 32;
} else
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enctype = "unknown";
vpn_progress(vpninfo, PRG_DEBUG, _("ESP encryption: 0x%02x (%s)\n"),
data[0], enctype);
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vpninfo->esp_enc = data[0];
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break;
}
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case GRP_ATTR(8, 2): {
const char *mactype;
if (attrlen != 1)
goto badlen;
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if (data[0] == HMAC_MD5) {
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mactype = "MD5";
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vpninfo->hmac_key_len = 16;
} else if (data[0] == HMAC_SHA1) {
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mactype = "SHA1";
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vpninfo->hmac_key_len = 20;
} else
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mactype = "unknown";
vpn_progress(vpninfo, PRG_DEBUG, _("ESP HMAC: 0x%02x (%s)\n"),
data[0], mactype);
vpninfo->esp_hmac = data[0];
break;
}
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case GRP_ATTR(8, 3):
if (attrlen != 1)
goto badlen;
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vpninfo->esp_compr = data[0];
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vpninfo->dtls_compr = data[0] ? COMPR_LZO : 0;
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vpn_progress(vpninfo, PRG_DEBUG, _("ESP compression: %d\n"), data[0]);
break;
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case GRP_ATTR(8, 4):
if (attrlen != 2)
goto badlen;
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i = load_be16(data);
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udp_sockaddr(vpninfo, i);
vpn_progress(vpninfo, PRG_DEBUG, _("ESP port: %d\n"), i);
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break;
case GRP_ATTR(8, 5):
if (attrlen != 4)
goto badlen;
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vpninfo->esp_lifetime_bytes = load_be32(data);
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vpn_progress(vpninfo, PRG_DEBUG, _("ESP key lifetime: %u bytes\n"),
vpninfo->esp_lifetime_bytes);
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break;
case GRP_ATTR(8, 6):
if (attrlen != 4)
goto badlen;
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vpninfo->esp_lifetime_seconds = load_be32(data);
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vpn_progress(vpninfo, PRG_DEBUG, _("ESP key lifetime: %u seconds\n"),
vpninfo->esp_lifetime_seconds);
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break;
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case GRP_ATTR(8, 9):
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if (attrlen != 4)
goto badlen;
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vpninfo->esp_ssl_fallback = load_be32(data);
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vpn_progress(vpninfo, PRG_DEBUG, _("ESP to SSL fallback: %u seconds\n"),
vpninfo->esp_ssl_fallback);
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break;
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case GRP_ATTR(8, 10):
if (attrlen != 4)
goto badlen;
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vpninfo->esp_replay_protect = load_be32(data);
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vpn_progress(vpninfo, PRG_DEBUG, _("ESP replay protection: %d\n"),
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load_be32(data));
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break;
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case GRP_ATTR(7, 1):
if (attrlen != 4)
goto badlen;
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memcpy(&vpninfo->esp_out.spi, data, 4);
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vpn_progress(vpninfo, PRG_DEBUG, _("ESP SPI (outbound): %x\n"),
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load_be32(data));
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break;
case GRP_ATTR(7, 2):
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if (attrlen != 0x40)
goto badlen;
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/* data contains enc_key and hmac_key concatenated */
memcpy(vpninfo->esp_out.enc_key, data, 0x40);
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vpn_progress(vpninfo, PRG_DEBUG, _("%d bytes of ESP secrets\n"),
attrlen);
break;
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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;
}
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static void put_len16(struct oc_text_buf *buf, int where)
{
int len = buf->pos - where;
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store_be16(buf->data + where - 2, len);
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}
static void put_len32(struct oc_text_buf *buf, int where)
{
int len = buf->pos - where;
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store_be32(buf->data + where - 4, len);
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}
/* 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 };
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static const unsigned char data_hdr[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x01, 0x2c, 0x01, 0x00, 0x00, 0x00,
0x01, 0x00, 0x00, 0x00, 0x00, 0x00 };
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#ifdef HAVE_ESP
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static const unsigned char esp_kmp_hdr[] = {
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x2e,
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 */
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#endif
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static const struct pkt esp_enable_pkt = {
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.next = NULL,
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{ .oncp = { .rec = { 0x21, 0x00 },
.kmp = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x2f,
0x01, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x0d } }
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},
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.data = {
0x00, 0x06, 0x00, 0x00, 0x00, 0x07, /* Group 6, len 7 */
0x00, 0x01, 0x00, 0x00, 0x00, 0x01, /* Attr 1, len 1 */
0x01
},
.len = 13
};
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static int queue_esp_control(struct openconnect_info *vpninfo, int enable)
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{
struct pkt *new = malloc(sizeof(*new) + 13);
if (!new)
return -ENOMEM;
memcpy(new, &esp_enable_pkt, sizeof(*new) + 13);
new->data[12] = enable;
queue_packet(&vpninfo->oncp_control_queue, new);
return 0;
}
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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;
}
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return load_be16(bytes + 6);
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}
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;
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int split_enc_hmac_keys = 0;
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kmplen = load_be16(bytes + ofs + 18);
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kmpend = ofs + kmplen;
if (kmpend > pktlen) {
eparse:
vpn_progress(vpninfo, PRG_ERR,
_("Failed to parse KMP message\n"));
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dump_buf_hex(vpninfo, PRG_ERR, '<', bytes, pktlen);
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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;
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group = load_be16(bytes + ofs);
grouplen = load_be32(bytes + ofs + 2);
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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);
return -EINVAL;
}
while (ofs < groupend) {
if (ofs + 6 > groupend)
goto eparse;
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attr = load_be16(bytes + ofs);
attrlen = load_be32(bytes + ofs + 2);
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ofs += 6;
if (attrlen + ofs > groupend)
goto eparse;
if (process_attr(vpninfo, group, attr, bytes + ofs, attrlen))
goto eparse;
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if (GRP_ATTR(group, attr)==GRP_ATTR(7, 2))
split_enc_hmac_keys = 1;
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ofs += attrlen;
}
}
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/* 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);
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return 0;
}
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int oncp_connect(struct openconnect_info *vpninfo)
{
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int ret, len, kmp, kmplen, group, check_len;
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struct oc_text_buf *reqbuf;
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unsigned char bytes[65536];
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/* XXX: We should do what cstp_connect() does to check that configuration
hasn't changed on a reconnect. */
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if (!vpninfo->cookies) {
ret = parse_cookie(vpninfo);
if (ret)
return ret;
}
ret = openconnect_open_https(vpninfo);
if (ret)
return ret;
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reqbuf = buf_alloc();
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buf_append(reqbuf, "POST /dana/js?prot=1&svc=4 HTTP/1.1\r\n");
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/* 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");
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oncp_common_headers(vpninfo, reqbuf);
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buf_append(reqbuf, "Content-Length: 256\r\n");
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buf_append(reqbuf, "\r\n");
if (buf_error(reqbuf)) {
vpn_progress(vpninfo, PRG_ERR,
_("Error creating oNCP negotiation request\n"));
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ret = buf_error(reqbuf);
goto out;
580
581
}
ret = vpninfo->ssl_write(vpninfo, reqbuf->data, reqbuf->pos);
582
583
584
if (ret < 0)
goto out;
585
ret = process_http_response(vpninfo, 1, NULL, reqbuf);
586
587
588
if (ret < 0)
goto out;
589
590
591
592
if (ret != 200) {
vpn_progress(vpninfo, PRG_ERR,
_("Unexpected %d result from server\n"),
ret);
593
594
ret = -EINVAL;
goto out;
595
596
}
597
598
599
/* 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. */
600
buf_truncate(reqbuf);
601
602
603
604
605
606
607
608
609
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"));
610
611
ret = buf_error(reqbuf);
goto out;
612
}
613
dump_buf_hex(vpninfo, PRG_DEBUG, '>', (void *)reqbuf->data, reqbuf->pos);
614
ret = vpninfo->ssl_write(vpninfo, reqbuf->data, reqbuf->pos);
615
616
617
618
619
620
if (ret != reqbuf->pos) {
if (ret >= 0) {
vpn_progress(vpninfo, PRG_ERR,
_("Short write in oNCP negotiation\n"));
ret = -EIO;
}
621
goto out;
622
}
623
624
625
626
/* Now we expect a three-byte response with what's presumably an
error code */
ret = vpninfo->ssl_read(vpninfo, (void *)bytes, 3);
627
check_len = load_le16(bytes);
628
629
if (ret < 0)
goto out;
630
631
vpn_progress(vpninfo, PRG_TRACE,
_("Read %d bytes of SSL record\n"), ret);
632
dump_buf_hex(vpninfo, PRG_TRACE, '<', (void *)bytes, ret);
633
634
if (ret != 3 || check_len < 1) {
635
636
637
vpn_progress(vpninfo, PRG_ERR,
_("Unexpected response of size %d after hostname packet\n"),
ret);
638
639
ret = -EINVAL;
goto out;
640
641
642
643
644
}
if (bytes[2]) {
vpn_progress(vpninfo, PRG_ERR,
_("Server response to hostname packet is error 0x%02x\n"),
bytes[2]);
645
646
647
648
649
650
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"));
651
652
ret = -EINVAL;
goto out;
653
654
}
655
656
657
658
659
660
661
662
663
664
665
666
/* 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));
check_len = load_le16(bytes);
} else {
len = vpninfo->ssl_read(vpninfo, (void *)(bytes+2), sizeof(bytes)-2) + 2;
check_len--;
}
667
668
if (len < 0) {
ret = len;
669
goto out;
670
}
671
vpn_progress(vpninfo, PRG_TRACE,
672
_("Read %d bytes of SSL record\n"), len);
673
674
if (len < 0x16 || check_len + 2 != len) {
675
676
vpn_progress(vpninfo, PRG_ERR,
_("Invalid packet waiting for KMP 301\n"));
677
dump_buf_hex(vpninfo, PRG_ERR, '<', bytes, len);
678
679
ret = -EINVAL;
goto out;
680
681
}
682
683
684
ret = check_kmp_header(vpninfo, bytes + 2, len);
if (ret < 0)
goto out;
685
686
687
688
689
690
691
692
/* 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;
693
}
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
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,
726
_("Failed to read continuation record of length %d\n"),
727
728
729
730
731
732
733
734
735
736
737
load_le16(l));
ret = -EINVAL;
goto out;
}
vpn_progress(vpninfo, PRG_TRACE,
_("Read additional %d bytes of KMP 301 message\n"),
thislen);
len += thislen;
}
ret = parse_conf_pkt(vpninfo, bytes + 2, len - 2, ret);
738
739
740
if (ret)
goto out;
741
742
743
buf_truncate(reqbuf);
buf_append_le16(reqbuf, 0); /* Length. We'll fix it later. */
buf_append_bytes(reqbuf, kmp_head, sizeof(kmp_head));
744
buf_append_be16(reqbuf, 303); /* KMP message 303 */
745
buf_append_bytes(reqbuf, kmp_tail_out, sizeof(kmp_tail_out));
746
buf_append_be16(reqbuf, 0); /* KMP message length */
747
748
749
750
751
752
753
754
755
756
757
758
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);
759
760
#ifdef HAVE_ESP
761
if (!openconnect_setup_esp_keys(vpninfo, 1)) {
762
struct esp *esp = &vpninfo->esp_in[vpninfo->current_esp_in];
763
764
765
766
/* 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));
767
buf_append_bytes(reqbuf, &esp->spi, sizeof(esp->spi));
768
buf_append_bytes(reqbuf, esp_kmp_part2, sizeof(esp_kmp_part2));
769
770
buf_append_bytes(reqbuf, &esp->enc_key, vpninfo->enc_key_len);
buf_append_bytes(reqbuf, &esp->hmac_key, 0x40 - vpninfo->enc_key_len);
771
772
773
774
775
776
if (buf_error(reqbuf)) {
vpn_progress(vpninfo, PRG_ERR,
_("Error negotiating ESP keys\n"));
ret = buf_error(reqbuf);
goto out;
}
777
}
778
#endif
779
/* Length at the start of the packet is little-endian */
780
store_le16(reqbuf->data, reqbuf->pos - 2);
781
782
783
vpn_progress(vpninfo, PRG_DEBUG, _("oNCP negotiation request outgoing:\n"));
dump_buf_hex(vpninfo, PRG_DEBUG, '>', (void *)reqbuf->data, reqbuf->pos);
784
ret = vpninfo->ssl_write(vpninfo, reqbuf->data, reqbuf->pos);
785
786
787
788
789
790
791
if (ret == reqbuf->pos)
ret = 0;
else if (ret >= 0) {
vpn_progress(vpninfo, PRG_ERR,
_("Short write in oNCP negotiation\n"));
ret = -EIO;
}
792
793
794
out:
if (ret)
openconnect_close_https(vpninfo, 0);
795
796
797
798
799
else {
monitor_fd_new(vpninfo, ssl);
monitor_read_fd(vpninfo, ssl);
monitor_except_fd(vpninfo, ssl);
}
800
buf_free(reqbuf);
801
802
803
804
805
vpninfo->oncp_rec_size = 0;
free(vpninfo->cstp_pkt);
vpninfo->cstp_pkt = NULL;
806
return ret;
807
808
}
809
810
static int oncp_receive_espkeys(struct openconnect_info *vpninfo, int len)
{
811
#ifdef HAVE_ESP
812
813
int ret;
814
ret = parse_conf_pkt(vpninfo, vpninfo->cstp_pkt->oncp.kmp, len + 20, 301);
815
816
817
if (!ret)
ret = openconnect_setup_esp_keys(vpninfo, 1);
if (!ret) {
818
struct esp *esp = &vpninfo->esp_in[vpninfo->current_esp_in];
819
unsigned char *p = vpninfo->cstp_pkt->oncp.kmp;
820
821
822
memcpy(p, esp_kmp_hdr, sizeof(esp_kmp_hdr));
p += sizeof(esp_kmp_hdr);
823
824
memcpy(p, &esp->spi, sizeof(esp->spi));
p += sizeof(esp->spi);
825
826
memcpy(p, esp_kmp_part2, sizeof(esp_kmp_part2));
p += sizeof(esp_kmp_part2);
827
828
829
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;
830
vpninfo->cstp_pkt->len = p - vpninfo->cstp_pkt->data;
831
832
store_le16(vpninfo->cstp_pkt->oncp.rec,
(p - vpninfo->cstp_pkt->oncp.kmp));
833
834
835
836
queue_packet(&vpninfo->oncp_control_queue, vpninfo->cstp_pkt);
vpninfo->cstp_pkt = NULL;
837
print_esp_keys(vpninfo, _("new incoming"), esp);
838
839
840
print_esp_keys(vpninfo, _("new outgoing"), &vpninfo->esp_out);
}
return ret;
841
842
843
844
845
#else
vpn_progress(vpninfo, PRG_DEBUG,
_("Ignoring ESP keys since ESP support not available in this build\n"));
return 0;
#endif
846
}
847
848
849
static int oncp_record_read(struct openconnect_info *vpninfo, void *buf, int len)
850
851
852
{
int ret;
853
854
if (!vpninfo->oncp_rec_size) {
unsigned char lenbuf[2];
855
856
857
858
859
860
861
ret = ssl_nonblock_read(vpninfo, 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 */
862
vpn_progress(vpninfo, PRG_ERR,
863
864
_("Read only 1 byte of oNCP length field\n"));
return -EIO;
865
}
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
vpninfo->oncp_rec_size = load_le16(lenbuf);
if (!vpninfo->oncp_rec_size) {
ret = ssl_nonblock_read(vpninfo, 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 {
vpn_progress(vpninfo, PRG_ERR,
_("Server terminated connection (reason: %d)\n"),
lenbuf[0]);
vpninfo->quit_reason = "Server terminated connection";
}
} else {
881
vpn_progress(vpninfo, PRG_ERR,
882
883
_("Server sent zero-length oNCP record\n"));
vpninfo->quit_reason = "Zero-length oNCP record";
884
}
885
return -EIO;
886
887
}
}
888
889
890
891
892
893
894
if (len > vpninfo->oncp_rec_size)
len = vpninfo->oncp_rec_size;
ret = ssl_nonblock_read(vpninfo, buf, len);
if (ret > 0)
vpninfo->oncp_rec_size -= ret;
return ret;
895
896
}
897
int oncp_mainloop(struct openconnect_info *vpninfo, int *timeout, int readable)
898
{
899
900
901
902
903
904
905
906
907
908
909
910
int ret;
int work_done = 0;
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. */
911
while (readable) {
912
int len, kmp, kmplen, iplen;
913
914
915
916
/* Some servers send us packets that are larger than
negitiated MTU. We reserve some estra space to
handle that */
int receive_mtu = MAX(16384, vpninfo->ip_info.mtu);
917
918
len = receive_mtu + vpninfo->pkt_trailer;
919
920
921
922
923
924
if (!vpninfo->cstp_pkt) {
vpninfo->cstp_pkt = malloc(sizeof(struct pkt) + len);
if (!vpninfo->cstp_pkt) {
vpn_progress(vpninfo, PRG_ERR, _("Allocation failed\n"));
break;
}
925
vpninfo->cstp_pkt->len = 0;
926
927
}
928
/*
929
930
931
932
933
934
935
* 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.
936
*
937
938
939
940
941
942
* 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.
943
*
944
945
946
947
948
949
950
951
952
* 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.
953
*/
954
955
956
957
958
/* 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,
959
receive_mtu + 20 - vpninfo->cstp_pkt->len);
960
961
if (!len)
break;
962
963
964
else if (len < 0) {
if (vpninfo->quit_reason)
return len;
965
goto do_reconnect;
966
}
967
968
969
970
vpninfo->cstp_pkt->len += len;
vpninfo->ssl_times.last_rx = time(NULL);
if (vpninfo->cstp_pkt->len < 20)
continue;
971
972
973
next_kmp:
/* Now we have a KMP header. It might already have been there */
974
975
kmp = load_be16(vpninfo->cstp_pkt->oncp.kmp + 6);
kmplen = load_be16(vpninfo->cstp_pkt->oncp.kmp + 18);
976
977
978
979
980
981
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);
982
983
984
switch (kmp) {
case 300:
985
986
987
988
989
990
991
992
993
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:
994
iplen = load_be16(vpninfo->cstp_pkt->data + 4) + 40;
995
996
997
998
999
1000
break;
default:
badiplen:
vpn_progress(vpninfo, PRG_ERR,
_("Unrecognised data packet\n"));
goto unknown_pkt;