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cstp.c
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/*
* OpenConnect (SSL + DTLS) VPN client
*
* Copyright © 2008-2015 Intel Corporation.
* Copyright © 2008 Nick Andrew <[email protected]>
*
* 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.
*/
#include <config.h>
#include "openconnect-internal.h"
#ifdef HAVE_LZ4
#include <lz4.h>
#ifndef HAVE_LZ4_COMPRESS_DEFAULT
#define LZ4_compress_default LZ4_compress_limitedOutput
#endif
#endif
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#if defined(__linux__)
/* For TCP_INFO */
# include <linux/tcp.h>
#endif
#include <time.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
/*
* Data packets are encapsulated in the SSL stream as follows:
*
* 0000: Magic "STF\x1"
* 0004: Big-endian 16-bit length (not including 8-byte header)
* 0006: Byte packet type (see openconnect-internal.h)
* 0008: data payload
*/
static const char data_hdr[8] = {
'S', 'T', 'F', 1,
0, 0, /* Length */
AC_PKT_DATA, /* Type */
0 /* Unknown */
};
/* Strange initialisers here to work around GCC PR#10676 (which was
* fixed in GCC 4.6 but it takes a while for some systems to catch
* up. */
static const struct pkt keepalive_pkt = {
.next = NULL,
{ .cstp.hdr = { 'S', 'T', 'F', 1, 0, 0, AC_PKT_KEEPALIVE, 0 } }
};
static const struct pkt dpd_pkt = {
.next = NULL,
{ .cstp.hdr = { 'S', 'T', 'F', 1, 0, 0, AC_PKT_DPD_OUT, 0 } }
};
static const struct pkt dpd_resp_pkt = {
.next = NULL,
{ .cstp.hdr = { 'S', 'T', 'F', 1, 0, 0, AC_PKT_DPD_RESP, 0 } }
};
#define UDP_HEADER_SIZE 8
#define IPV4_HEADER_SIZE 20
#define IPV6_HEADER_SIZE 40
/* Calculate MTU to request. Old servers simply use the X-CSTP-MTU: header,
* which represents the tunnel MTU, while new servers do calculations on the
* X-CSTP-Base-MTU: header which represents the link MTU between client
* and server.
*
* If possible, the legacy MTU value should be the TCP MSS less 5 bytes of
* TLS and 8 bytes of CSTP overhead. We can get the MSS from either the
* TCP_INFO or TCP_MAXSEG sockopts.
*
* The base MTU comes from the TCP_INFO sockopt under Linux, but I don't know
* how to work it out on other systems. So leave it blank and do things the
* legacy way there. Contributions welcome...
*
* If we don't even have TCP_MAXSEG, then default to sending a legacy MTU of
* 1406 which is what we always used to do.
*/
static void calculate_dtls_mtu(struct openconnect_info *vpninfo, int *base_mtu, int *mtu)
{
*mtu = vpninfo->reqmtu;
*base_mtu = vpninfo->basemtu;
#if defined(__linux__) && defined(TCP_INFO)
if (!*mtu || !*base_mtu) {
struct tcp_info ti;
socklen_t ti_size = sizeof(ti);
if (!getsockopt(vpninfo->ssl_fd, IPPROTO_TCP, TCP_INFO,
&ti, &ti_size)) {
vpn_progress(vpninfo, PRG_DEBUG,
_("TCP_INFO rcv mss %d, snd mss %d, adv mss %d, pmtu %d\n"),
ti.tcpi_rcv_mss, ti.tcpi_snd_mss, ti.tcpi_advmss, ti.tcpi_pmtu);
if (!*base_mtu) {
*base_mtu = ti.tcpi_pmtu;
}
if (!*base_mtu) {
if (ti.tcpi_rcv_mss < ti.tcpi_snd_mss)
*base_mtu = ti.tcpi_rcv_mss - 13;
else
*base_mtu = ti.tcpi_snd_mss - 13;
}
}
}
#endif
#ifdef TCP_MAXSEG
if (!*base_mtu) {
int mss;
socklen_t mss_size = sizeof(mss);
if (!getsockopt(vpninfo->ssl_fd, IPPROTO_TCP, TCP_MAXSEG,
(void *)&mss, &mss_size)) {
vpn_progress(vpninfo, PRG_DEBUG, _("TCP_MAXSEG %d\n"), mss);
*base_mtu = mss - 13;
}
}
#endif
if (!*base_mtu) {
/* Default */
*base_mtu = 1406;
}
if (*base_mtu < 1280)
*base_mtu = 1280;
if (!*mtu) {
/* remove IP/UDP and DTLS overhead from base MTU to calculate tunnel MTU */
*mtu = *base_mtu - DTLS_OVERHEAD - UDP_HEADER_SIZE;
if (vpninfo->peer_addr->sa_family == AF_INET6)
*mtu -= IPV6_HEADER_SIZE;
else
*mtu -= IPV4_HEADER_SIZE;
}
}
static void append_compr_types(struct oc_text_buf *buf, const char *proto, int avail)
{
if (avail) {
char sep = ' ';
buf_append(buf, "X-%s-Accept-Encoding:", proto);
if (avail & COMPR_LZ4) {
buf_append(buf, "%coc-lz4", sep);
sep = ',';
}
if (avail & COMPR_LZS) {
buf_append(buf, "%clzs", sep);
sep = ',';
}
if (avail & COMPR_DEFLATE)
buf_append(buf, "%cdeflate", sep);
buf_append(buf, "\r\n");
}
}
static void append_mobile_headers(struct openconnect_info *vpninfo, struct oc_text_buf *buf)
{
if (vpninfo->mobile_platform_version) {
buf_append(buf, "X-AnyConnect-Identifier-ClientVersion: %s\r\n",
vpninfo->version_string ? : openconnect_version_str);
buf_append(buf, "X-AnyConnect-Identifier-Platform: %s\r\n",
vpninfo->platname);
buf_append(buf, "X-AnyConnect-Identifier-PlatformVersion: %s\r\n",
vpninfo->mobile_platform_version);
buf_append(buf, "X-AnyConnect-Identifier-DeviceType: %s\r\n",
vpninfo->mobile_device_type);
buf_append(buf, "X-AnyConnect-Identifier-Device-UniqueID: %s\r\n",
vpninfo->mobile_device_uniqueid);
}
}
static int parse_hex_val(const char *str, unsigned char *storage, unsigned int max_storage_len, int *changed)
{
int len = strlen(str);
unsigned i;
if (len % 2 == 1 || len > 2*max_storage_len) {
return -EINVAL;
}
for (i = 0; i < len; i += 2) {
unsigned char c = unhex(str + i);
if (storage[i/2] != c) {
storage[i/2] = c;
*changed = 1;
}
}
return len/2;
}
#ifdef HAVE_HPKE_SUPPORT
static void append_connect_strap_headers(struct openconnect_info *vpninfo,
struct oc_text_buf *buf, int rekey)
{
buf_append(buf, "X-AnyConnect-STRAP-Verify: ");
append_strap_verify(vpninfo, buf, rekey);
buf_append(buf, "\r\n");
buf_append(buf, "X-AnyConnect-STRAP-Pubkey: %s\r\n", vpninfo->strap_pubkey);
}
#endif
static int start_cstp_connection(struct openconnect_info *vpninfo, int strap_rekey)
{
struct oc_text_buf *reqbuf;
char buf[65536];
int i;
int dtls_secret_set = 0;
int retried = 0, sessid_found = 0;
const char *old_addr = vpninfo->ip_info.addr;
const char *old_addr6 = vpninfo->ip_info.addr6;
const char *banner = NULL;
int base_mtu = 0, mtu = 0;
retry:
calculate_dtls_mtu(vpninfo, &base_mtu, &mtu);
vpninfo->cstp_basemtu = base_mtu;
reqbuf = buf_alloc();
buf_append(reqbuf, "CONNECT /CSCOSSLC/tunnel HTTP/1.1\r\n");
if (vpninfo->port != 443)
buf_append(reqbuf, "Host: %s:%d\r\n", vpninfo->hostname, vpninfo->port);
else
buf_append(reqbuf, "Host: %s\r\n", vpninfo->hostname);
buf_append(reqbuf, "User-Agent: %s\r\n", vpninfo->useragent);
buf_append(reqbuf, "Cookie: webvpn=%s\r\n", http_get_cookie(vpninfo, "webvpn"));
buf_append(reqbuf, "X-CSTP-Version: 1\r\n");
buf_append(reqbuf, "X-CSTP-Hostname: %s\r\n", vpninfo->localname);
#ifdef HAVE_HPKE_SUPPORT
if (!vpninfo->no_external_auth && vpninfo->strap_pubkey)
append_connect_strap_headers(vpninfo, reqbuf, strap_rekey);
#endif
append_mobile_headers(vpninfo, reqbuf);
append_compr_types(reqbuf, "CSTP", vpninfo->req_compr);
buf_append(reqbuf, "X-CSTP-Base-MTU: %d\r\n", base_mtu);
if (mtu)
buf_append(reqbuf, "X-CSTP-MTU: %d\r\n", mtu);
buf_append(reqbuf, "X-CSTP-Address-Type: %s\r\n",
vpninfo->disable_ipv6 ? "IPv4" : "IPv6,IPv4");
/* Explicitly request the same IPv4 and IPv6 addresses on reconnect
*
* XX: It's not clear which Cisco servers attempt to follow specific
* IP address requests from the X-CSTP-Address headers in the CONNECT
* request; most seem to ignore it. */
if (old_addr)
buf_append(reqbuf, "X-CSTP-Address: %s\r\n", old_addr);
if (!vpninfo->disable_ipv6) {
buf_append(reqbuf, "X-CSTP-Full-IPv6-Capability: true\r\n");
if (old_addr6)
buf_append(reqbuf, "X-CSTP-Address: %s\r\n", old_addr6);
}
#ifdef HAVE_DTLS
if (vpninfo->dtls_state != DTLS_DISABLED) {
/* The X-DTLS-Master-Secret is only used for the legacy protocol negotiation
* which required the client to send explicitly the secret. In the PSK-NEGOTIATE
* method, the master secret is implicitly agreed on */
buf_append(reqbuf, "X-DTLS-Master-Secret: ");
for (i = 0; i < sizeof(vpninfo->dtls_secret); i++) {
buf_append(reqbuf, "%02X", vpninfo->dtls_secret[i]);
dtls_secret_set |= vpninfo->dtls_secret[i];
}
buf_append(reqbuf, "\r\n");
if (!dtls_secret_set) {
vpn_progress(vpninfo, PRG_ERR,
_("CRITICAL ERROR: DTLS master secret is uninitialised. Please report this.\n"));
buf_free(reqbuf);
return -EINVAL;
}
if (vpninfo->dtls_ciphers || vpninfo->dtls12_ciphers) {
if (vpninfo->dtls_ciphers)
buf_append(reqbuf, "X-DTLS-CipherSuite: %s\r\n", vpninfo->dtls_ciphers);
if (vpninfo->dtls12_ciphers)
buf_append(reqbuf, "X-DTLS12-CipherSuite: %s\r\n", vpninfo->dtls12_ciphers);
} else {
struct oc_text_buf *dtls_cl, *dtls12_cl;
dtls_cl = buf_alloc();
dtls12_cl = buf_alloc();
gather_dtls_ciphers(vpninfo, dtls_cl, dtls12_cl);
if (!buf_error(dtls_cl) && dtls_cl->pos)
buf_append(reqbuf, "X-DTLS-CipherSuite: %s\r\n", dtls_cl->data);
if (!buf_error(dtls12_cl) && dtls12_cl->pos)
buf_append(reqbuf, "X-DTLS12-CipherSuite: %s\r\n", dtls12_cl->data);
buf_free(dtls_cl);
buf_free(dtls12_cl);
}
append_compr_types(reqbuf, "DTLS", vpninfo->req_compr & ~COMPR_DEFLATE);
vpninfo->delay_tunnel_reason = "DTLS MTU detection";
}
#endif
buf_append(reqbuf, "\r\n");
if (buf_error(reqbuf)) {
vpn_progress(vpninfo, PRG_ERR,
_("Error creating HTTPS CONNECT request\n"));
return buf_free(reqbuf);
}
if (vpninfo->dump_http_traffic)
dump_buf(vpninfo, '>', reqbuf->data);
vpninfo->ssl_write(vpninfo, reqbuf->data, reqbuf->pos);
buf_free(reqbuf);
/* FIXME: Use process_http_response() instead of reimplementing it. It has
a header callback function, and can cope with CONNECT requests. */
if ((i = vpninfo->ssl_gets(vpninfo, buf, 65536)) < 0) {
if (i == -EINTR)
return i;
vpn_progress(vpninfo, PRG_ERR,
_("Error fetching HTTPS response\n"));
if (!retried) {
retried = 1;
openconnect_close_https(vpninfo, 0);
if (openconnect_open_https(vpninfo)) {
vpn_progress(vpninfo, PRG_ERR,
_("Failed to open HTTPS connection to %s\n"),
vpninfo->hostname);
return -EIO;
}
goto retry;
}
return -EINVAL;
}
if (strncmp(buf, "HTTP/1.1 200 ", 13)) {
if (!strncmp(buf, "HTTP/1.1 503 ", 13)) {
/* "Service Unavailable. Why? */
const char *reason = "<unknown>";
while ((vpninfo->ssl_gets(vpninfo, buf, sizeof(buf)))) {
if (!strncmp(buf, "X-Reason: ", 10)) {
reason = buf + 10;
break;
}
}
vpn_progress(vpninfo, PRG_ERR,
_("VPN service unavailable; reason: %s\n"),
reason);
return -EINVAL;
}
vpn_progress(vpninfo, PRG_ERR,
_("Got inappropriate HTTP CONNECT response: %s\n"),
buf);
if (!strncmp(buf, "HTTP/1.1 401 ", 13))
return -EPERM;
return -EINVAL;
}
vpn_progress(vpninfo, PRG_INFO, _("Got CONNECT response: %s\n"), buf);
/* We may have advertised it, but we only do it if the server agrees */
vpninfo->cstp_compr = vpninfo->dtls_compr = 0;
mtu = 0;
struct oc_vpn_option *new_cstp_opts = NULL;
struct oc_vpn_option *new_dtls_opts = NULL;
struct oc_vpn_option **next_dtls_option = &new_dtls_opts;
struct oc_vpn_option **next_cstp_option = &new_cstp_opts;
struct oc_ip_info new_ip_info = {};
int ret = 0;
while ((ret = vpninfo->ssl_gets(vpninfo, buf, sizeof(buf)))) {
struct oc_vpn_option *new_option;
char *colon;
if (ret < 0)
goto err;
colon = strchr(buf, ':');
if (!colon)
continue;
*colon = 0;
colon++;
if (*colon == ' ')
colon++;
if (strncmp(buf, "X-DTLS-", 7) &&
strncmp(buf, "X-CSTP-", 7) &&
strncmp(buf, "X-DTLS12-", 9))
continue;
new_option = malloc(sizeof(*new_option));
if (!new_option) {
vpn_progress(vpninfo, PRG_ERR, _("No memory for options\n"));
ret = -ENOMEM;
goto err;
}
new_option->option = strdup(buf);
new_option->value = strdup(colon);
new_option->next = NULL;
if (!new_option->option || !new_option->value) {
vpn_progress(vpninfo, PRG_ERR, _("No memory for options\n"));
free(new_option->option);
free(new_option->value);
free(new_option);
ret = -ENOMEM;
goto err;
}
/* This contains the whole document, including the webvpn cookie. */
if (!strcasecmp(buf, "X-CSTP-Post-Auth-XML"))
vpn_progress(vpninfo, PRG_DEBUG, "%s: %s\n", buf, _("<elided>"));
else
vpn_progress(vpninfo, PRG_DEBUG, "%s: %s\n", buf, colon);
if (!strncmp(buf, "X-DTLS-", (i = 7)) || !strncmp(buf, "X-DTLS12-", (i = 9))) {
*next_dtls_option = new_option;
next_dtls_option = &new_option->next;
if (!strcmp(buf + i, "MTU")) {
int dtlsmtu = atol(colon);
if (dtlsmtu > mtu)
mtu = dtlsmtu;
} else if (!strcmp(buf + i, "Session-ID")) {
int dtls_sessid_changed = 0;
int vsize;
vsize = parse_hex_val(colon, vpninfo->dtls_session_id, sizeof(vpninfo->dtls_session_id), &dtls_sessid_changed);
if (vsize != 32) {
vpn_progress(vpninfo, PRG_ERR,
_("X-DTLS-Session-ID not 64 characters; is: \"%s\"\n"),
colon);
vpninfo->dtls_attempt_period = 0;
ret = -EINVAL;
goto err;
}
sessid_found = 1;
if (dtls_sessid_changed && vpninfo->dtls_state > DTLS_SLEEPING)
vpninfo->dtls_need_reconnect = 1;
} else if (!strcmp(buf + i, "App-ID")) {
int dtls_appid_changed = 0;
int vsize;
vsize = parse_hex_val(colon, vpninfo->dtls_app_id, sizeof(vpninfo->dtls_app_id), &dtls_appid_changed);
if (vsize <= 0) {
vpn_progress(vpninfo, PRG_ERR,
_("X-DTLS-Session-ID is invalid; is: \"%s\"\n"),
colon);
vpninfo->dtls_attempt_period = 0;
ret = -EINVAL;
goto err;
}
vpninfo->dtls_app_id_size = vsize;
sessid_found = 1;
if (dtls_appid_changed && vpninfo->dtls_state > DTLS_SLEEPING)
vpninfo->dtls_need_reconnect = 1;
} else if (!strcmp(buf + i, "Content-Encoding")) {
if (!strcmp(colon, "lzs"))
vpninfo->dtls_compr = COMPR_LZS;
else if (!strcmp(colon, "oc-lz4"))
vpninfo->dtls_compr = COMPR_LZ4;
else {
vpn_progress(vpninfo, PRG_ERR,
_("Unknown DTLS-Content-Encoding %s\n"),
colon);
ret = -EINVAL;
goto err;
}
} else if (!strcmp(buf + i, "CipherSuite")) {
/* Remember if it came from a 'X-DTLS12-CipherSuite:' header */
vpninfo->dtls12 = (i == 9);
vpninfo->dtls_cipher = strdup(colon);
} else if (!strcmp(buf + i, "Port")) {
int dtls_port = atol(colon);
if (dtls_port)
udp_sockaddr(vpninfo, dtls_port);
} else if (!strcmp(buf + i, "Keepalive")) {
vpninfo->dtls_times.keepalive = atol(colon);
} else if (!strcmp(buf + i, "DPD")) {
int j = atol(colon);
if (j && !vpninfo->dtls_times.dpd)
vpninfo->dtls_times.dpd = j;
} else if (!strcmp(buf + i, "Rekey-Method")) {
if (!strcmp(colon, "new-tunnel"))
vpninfo->dtls_times.rekey_method = REKEY_TUNNEL;
else if (!strcmp(colon, "ssl"))
vpninfo->dtls_times.rekey_method = REKEY_SSL;
else
vpninfo->dtls_times.rekey_method = REKEY_NONE;
} else if (!strcmp(buf + i, "Rekey-Time")) {
vpninfo->dtls_times.rekey = atol(colon);
}
continue;
}
/* CSTP options... */
*next_cstp_option = new_option;
next_cstp_option = &new_option->next;
if (!strcmp(buf + 7, "Keepalive")) {
vpninfo->ssl_times.keepalive = atol(colon);
} else if (!strcmp(buf + 7, "Lease-Duration") ||
!strcmp(buf + 7, "Session-Timeout") ||
!strcmp(buf + 7, "Session-Timeout-Remaining")) {
/* XX: Distinction between Lease-Duration and Session-Timeout is rather unclear. Cisco doc:
* https://www.cisco.com/assets/sol/sb/RV345P_Emulators/RV345P_Emulator_v1-0-01-17/help/help/t_SSL_VPN.html
* Empirically, it appears that the best behavior is to accept whichever of these headers has the
* lowest non-zero value.
*/
long j = atol(colon);
if (j && (!vpninfo->auth_expiration || j < vpninfo->auth_expiration))
vpninfo->auth_expiration = time(NULL) + j;
} else if (!strcmp(buf + 7, "Idle-Timeout")) {
vpninfo->idle_timeout = atol(colon);
} else if (!strcmp(buf + 7, "DPD")) {
int j = atol(colon);
if (j && !vpninfo->ssl_times.dpd)
vpninfo->ssl_times.dpd = j;
} else if (!strcmp(buf + 7, "Rekey-Time")) {
vpninfo->ssl_times.rekey = atol(colon);
} else if (!strcmp(buf + 7, "Rekey-Method")) {
if (!strcmp(colon, "new-tunnel"))
vpninfo->ssl_times.rekey_method = REKEY_TUNNEL;
else if (!strcmp(colon, "ssl"))
vpninfo->ssl_times.rekey_method = REKEY_SSL;
else
vpninfo->ssl_times.rekey_method = REKEY_NONE;
} else if (!strcmp(buf + 7, "Content-Encoding")) {
if (!strcmp(colon, "deflate"))
vpninfo->cstp_compr = COMPR_DEFLATE;
else if (!strcmp(colon, "lzs"))
vpninfo->cstp_compr = COMPR_LZS;
else if (!strcmp(colon, "oc-lz4"))
vpninfo->cstp_compr = COMPR_LZ4;
else {
vpn_progress(vpninfo, PRG_ERR,
_("Unknown CSTP-Content-Encoding %s\n"),
colon);
ret= -EINVAL;
goto err;
}
} else if (!strcmp(buf + 7, "Base-MTU")) {
vpninfo->cstp_basemtu = atol(colon);
} else if (!strcmp(buf + 7, "MTU")) {
int cstpmtu = atol(colon);
if (cstpmtu > mtu)
mtu = cstpmtu;
} else if (!strcmp(buf + 7, "DynDNS")) {
if (!strcmp(colon, "true"))
vpninfo->is_dyndns = 1;
} else if (!strcmp(buf + 7, "Address-IP6")) {
new_ip_info.netmask6 = new_option->value;
} else if (!strcmp(buf + 7, "Address")) {
if (strchr(new_option->value, ':')) {
if (!vpninfo->disable_ipv6)
new_ip_info.addr6 = new_option->value;
} else
new_ip_info.addr = new_option->value;
} else if (!strcmp(buf + 7, "Netmask")) {
if (strchr(new_option->value, ':')) {
if (!vpninfo->disable_ipv6)
new_ip_info.netmask6 = new_option->value;
} else
new_ip_info.netmask = new_option->value;
} else if (!strcmp(buf + 7, "DNS") ||
!strcmp(buf + 7, "DNS-IP6")) {
int j;
for (j = 0; j < 3; j++) {
if (!new_ip_info.dns[j]) {
new_ip_info.dns[j] = new_option->value;
break;
}
}
} else if (!strcmp(buf + 7, "NBNS")) {
int j;
for (j = 0; j < 3; j++) {
if (!new_ip_info.nbns[j]) {
new_ip_info.nbns[j] = new_option->value;
break;
}
}
} else if (!strcmp(buf + 7, "Default-Domain")) {
new_ip_info.domain = new_option->value;
} else if (!strcmp(buf + 7, "MSIE-Proxy-PAC-URL")) {
new_ip_info.proxy_pac = new_option->value;
} else if (!strcmp(buf + 7, "Banner")) {
banner = new_option->value;
} else if (!strcmp(buf + 7, "Split-DNS")) {
struct oc_split_include *dns = malloc(sizeof(*dns));
if (!dns)
continue;
dns->route = new_option->value;
dns->next = new_ip_info.split_dns;
new_ip_info.split_dns = dns;
} else if (!strcmp(buf + 7, "Split-Include") || !strcmp(buf + 7, "Split-Include-IP6")) {
struct oc_split_include *inc = malloc(sizeof(*inc));
if (!inc)
continue;
inc->route = new_option->value;
inc->next = new_ip_info.split_includes;
new_ip_info.split_includes = inc;
} else if (!strcmp(buf + 7, "Split-Exclude") || !strcmp(buf + 7, "Split-Exclude-IP6")) {
struct oc_split_include *exc = malloc(sizeof(*exc));
if (!exc)
continue;
exc->route = new_option->value;
exc->next = new_ip_info.split_excludes;
new_ip_info.split_excludes = exc;
}
}
if (!mtu) {
vpn_progress(vpninfo, PRG_ERR,
_("No MTU received. Aborting\n"));
ret = -EINVAL;
goto err;
}
new_ip_info.mtu = mtu;
ret = install_vpn_opts(vpninfo, new_cstp_opts, &new_ip_info);
if (ret) {
err:
free_optlist(new_cstp_opts);
free_optlist(new_dtls_opts);
free_split_routes(&new_ip_info);
return ret;
}
/* DTLS opts are a special case. Perhaps should have been in the
* CSTP opts list anyway. This all very Cisco-specific. */
free_optlist(vpninfo->dtls_options);
vpninfo->dtls_options = new_dtls_opts;
vpninfo->banner = banner;
vpn_progress(vpninfo, PRG_INFO, _("CSTP connected. DPD %d, Keepalive %d\n"),
vpninfo->ssl_times.dpd, vpninfo->ssl_times.keepalive);
monitor_fd_new(vpninfo, ssl);
monitor_read_fd(vpninfo, ssl);
monitor_except_fd(vpninfo, ssl);
if (!sessid_found)
vpninfo->dtls_attempt_period = 0;
if (vpninfo->ssl_times.rekey <= 0)
vpninfo->ssl_times.rekey_method = REKEY_NONE;
vpninfo->ssl_times.last_rekey = vpninfo->ssl_times.last_rx =
vpninfo->ssl_times.last_tx = time(NULL);
return 0;
}
int cstp_connect(struct openconnect_info *vpninfo)
{
int ret;
int deflate_bufsize = 0;
int compr_type;
int strap_rekey = 1;
if (!vpninfo->cookies) {
internal_split_cookies(vpninfo, 0, "webvpn");
#ifdef HAVE_HPKE_SUPPORT
if (!vpninfo->no_external_auth) {
const char *strap_privkey = http_get_cookie(vpninfo, "openconnect_strapkey");
if (strap_privkey && *strap_privkey) {
int derlen;
void *der = openconnect_base64_decode(&derlen, strap_privkey);
if (der && !ingest_strap_privkey(vpninfo, der, derlen)) {
strap_rekey = 0;
vpn_progress(vpninfo, PRG_DEBUG,
_("Ingested STRAP public key %s\n"),
vpninfo->strap_pubkey);
}
}
}
#endif
http_add_cookie(vpninfo, "openconnect_strapkey", "", 1);
}
/* This needs to be done before openconnect_setup_dtls() because it's
sent with the CSTP CONNECT handshake. Even if we don't end up doing
DTLS. */
if (vpninfo->dtls_state == DTLS_NOSECRET) {
if (openconnect_random(vpninfo->dtls_secret, sizeof(vpninfo->dtls_secret)))
return -EINVAL;
/* The application will later call openconnect_setup_dtls() */
vpninfo->dtls_state = DTLS_SECRET;
}
ret = openconnect_open_https(vpninfo);
if (ret)
return ret;
ret = start_cstp_connection(vpninfo, strap_rekey);
if (ret)
goto out;
/* Allow for the theoretical possibility of having *different*
* compression type for CSTP and DTLS. Although all we've seen
* in practice is that one is enabled and the other isn't. */
compr_type = vpninfo->cstp_compr | vpninfo->dtls_compr;
/* This will definitely be smaller than zlib's */
if (compr_type & (COMPR_LZS|COMPR_LZ4))
deflate_bufsize = vpninfo->ip_info.mtu;
/* If deflate compression is enabled (which is CSTP-only), it needs its
* context to be allocated. */
if (compr_type & COMPR_DEFLATE) {
vpninfo->deflate_adler32 = 1;
vpninfo->inflate_adler32 = 1;
if (inflateInit2(&vpninfo->inflate_strm, -12) ||
deflateInit2(&vpninfo->deflate_strm, Z_DEFAULT_COMPRESSION,
Z_DEFLATED, -12, 9, Z_DEFAULT_STRATEGY)) {
vpn_progress(vpninfo, PRG_ERR, _("Compression setup failed\n"));
ret = -ENOMEM;
goto out;
}
/* Add four bytes for the adler32 */
deflate_bufsize = deflateBound(&vpninfo->deflate_strm,
vpninfo->ip_info.mtu) + 4;
}
/* If *any* compression is enabled, we'll need a deflate_pkt to compress into */
if (deflate_bufsize > vpninfo->deflate_pkt_size) {
free_pkt(vpninfo, vpninfo->deflate_pkt);
vpninfo->deflate_pkt = alloc_pkt(vpninfo, deflate_bufsize);
if (!vpninfo->deflate_pkt) {
vpninfo->deflate_pkt_size = 0;
vpn_progress(vpninfo, PRG_ERR,
_("Allocation of deflate buffer failed\n"));
ret = -ENOMEM;
goto out;
}
vpninfo->deflate_pkt_size = deflate_bufsize;
memset(vpninfo->deflate_pkt, 0, sizeof(struct pkt));
memcpy(vpninfo->deflate_pkt->cstp.hdr, data_hdr, 8);
vpninfo->deflate_pkt->cstp.hdr[6] = AC_PKT_COMPRESSED;
}
out:
if (ret < 0)
openconnect_close_https(vpninfo, 0);
return ret;
}
static int cstp_reconnect(struct openconnect_info *vpninfo)
{
if (vpninfo->cstp_compr == COMPR_DEFLATE) {
/* Requeue the original packet that was deflated */
if (vpninfo->current_ssl_pkt == vpninfo->deflate_pkt) {
vpninfo->current_ssl_pkt = NULL;
queue_packet(&vpninfo->outgoing_queue, vpninfo->pending_deflated_pkt);
vpninfo->pending_deflated_pkt = NULL;
}
inflateEnd(&vpninfo->inflate_strm);
deflateEnd(&vpninfo->deflate_strm);
}
return ssl_reconnect(vpninfo);
}
int decompress_and_queue_packet(struct openconnect_info *vpninfo, int compr_type,
unsigned char *buf, int len)
{
/* Some servers send us packets that are larger than
negotiated MTU after decompression. We reserve some extra
space to handle that */
int receive_mtu = MAX(16384, vpninfo->ip_info.mtu);
struct pkt *new = alloc_pkt(vpninfo, receive_mtu);
const char *comprname;
if (!new)
return -ENOMEM;
new->next = NULL;
if (compr_type == COMPR_DEFLATE) {
uint32_t pkt_sum;
comprname = "deflate";
vpninfo->inflate_strm.next_in = buf;
vpninfo->inflate_strm.avail_in = len - 4;
vpninfo->inflate_strm.next_out = new->data;
vpninfo->inflate_strm.avail_out = receive_mtu;
vpninfo->inflate_strm.total_out = 0;
if (inflate(&vpninfo->inflate_strm, Z_SYNC_FLUSH)) {
vpn_progress(vpninfo, PRG_ERR, _("inflate failed\n"));
free(new);
return -EINVAL;
}
new->len = vpninfo->inflate_strm.total_out;
vpninfo->inflate_adler32 = adler32(vpninfo->inflate_adler32,
new->data, new->len);
pkt_sum = load_be32(buf + len - 4);
if (vpninfo->inflate_adler32 != pkt_sum)
vpninfo->quit_reason = "Compression (inflate) adler32 failure";
} else if (compr_type == COMPR_LZS) {
comprname = "LZS";
new->len = lzs_decompress(new->data, receive_mtu, buf, len);
if (new->len <= 0) {
len = new->len;
if (len == 0)
len = -EINVAL;
vpn_progress(vpninfo, PRG_ERR, _("LZS decompression failed: %s\n"),
strerror(-len));
free(new);
return len;
}
#ifdef HAVE_LZ4
} else if (compr_type == COMPR_LZ4) {
comprname = "LZ4";
new->len = LZ4_decompress_safe((void *)buf, (void *)new->data, len, receive_mtu);
if (new->len <= 0) {
len = new->len;
if (len == 0)
len = -EINVAL;
vpn_progress(vpninfo, PRG_ERR, _("LZ4 decompression failed\n"));
free(new);
return len;
}
#endif
} else {
vpn_progress(vpninfo, PRG_ERR,
_("Unknown compression type %d\n"), compr_type);
free(new);
return -EINVAL;
}
vpn_progress(vpninfo, PRG_TRACE,
_("Received %s compressed data packet of %d bytes (was %d)\n"),
comprname, new->len, len);
queue_packet(&vpninfo->incoming_queue, new);
return 0;
}
int compress_packet(struct openconnect_info *vpninfo, int compr_type, struct pkt *this)
{
int ret;
if (compr_type == COMPR_DEFLATE) {
vpninfo->deflate_strm.next_in = this->data;
vpninfo->deflate_strm.avail_in = this->len;
vpninfo->deflate_strm.next_out = (void *)vpninfo->deflate_pkt->data;
vpninfo->deflate_strm.avail_out = vpninfo->deflate_pkt_size - 4;
vpninfo->deflate_strm.total_out = 0;
ret = deflate(&vpninfo->deflate_strm, Z_SYNC_FLUSH);
if (ret) {
vpn_progress(vpninfo, PRG_ERR, _("deflate failed %d\n"), ret);
/* Things are going to go horribly wrong if we try to do any
more compression. Give up entirely. */
vpninfo->cstp_compr = 0;
return -EIO;
}
/* Add ongoing adler32 to tail of compressed packet */
vpninfo->deflate_adler32 = adler32(vpninfo->deflate_adler32,
this->data, this->len);
store_be32(&vpninfo->deflate_pkt->data[vpninfo->deflate_strm.total_out],
vpninfo->deflate_adler32);
vpninfo->deflate_pkt->len = vpninfo->deflate_strm.total_out + 4;
return 0;
} else if (compr_type == COMPR_LZS) {
if (this->len < 40)
return -EFBIG;
ret = lzs_compress(vpninfo->deflate_pkt->data, this->len,
this->data, this->len);
if (ret < 0)
return ret;
vpninfo->deflate_pkt->len = ret;
return 0;
#ifdef HAVE_LZ4
} else if (compr_type == COMPR_LZ4) {
if (this->len < 40)
return -EFBIG;
ret = LZ4_compress_default((void *)this->data, (void *)vpninfo->deflate_pkt->data,
this->len, this->len);
if (ret <= 0) {
if (ret == 0)
ret = -EFBIG;
return ret;
}
vpninfo->deflate_pkt->len = ret;
return 0;
#endif
} else
return -EINVAL;
return 0;
}
int cstp_mainloop(struct openconnect_info *vpninfo, int *timeout, int readable)
{
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. */
while (readable) {
/* 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->deflate_pkt_size ? : vpninfo->ip_info.mtu);
int len, payload_len;
if (!vpninfo->cstp_pkt) {
vpninfo->cstp_pkt = alloc_pkt(vpninfo, receive_mtu);
if (!vpninfo->cstp_pkt) {
vpn_progress(vpninfo, PRG_ERR, _("Allocation failed\n"));
break;
}
}
len = ssl_nonblock_read(vpninfo, 0, vpninfo->cstp_pkt->cstp.hdr, receive_mtu + 8);
if (!len)
break;
if (len < 0)
goto do_reconnect;
if (len < 8) {
vpn_progress(vpninfo, PRG_ERR, _("Short packet received (%d bytes)\n"), len);
vpninfo->quit_reason = "Short packet received";
return 1;
}
if (vpninfo->cstp_pkt->cstp.hdr[0] != 'S' || vpninfo->cstp_pkt->cstp.hdr[1] != 'T' ||
vpninfo->cstp_pkt->cstp.hdr[2] != 'F' || vpninfo->cstp_pkt->cstp.hdr[3] != 1 ||
vpninfo->cstp_pkt->cstp.hdr[7])
goto unknown_pkt;
payload_len = load_be16(vpninfo->cstp_pkt->cstp.hdr + 4);
if (len != 8 + payload_len) {
vpn_progress(vpninfo, PRG_ERR,
_("Unexpected packet length. SSL_read returned %d but packet is\n"),
len);
vpn_progress(vpninfo, PRG_ERR,
"%02x %02x %02x %02x %02x %02x %02x %02x\n",
vpninfo->cstp_pkt->cstp.hdr[0], vpninfo->cstp_pkt->cstp.hdr[1],
vpninfo->cstp_pkt->cstp.hdr[2], vpninfo->cstp_pkt->cstp.hdr[3],
vpninfo->cstp_pkt->cstp.hdr[4], vpninfo->cstp_pkt->cstp.hdr[5],
vpninfo->cstp_pkt->cstp.hdr[6], vpninfo->cstp_pkt->cstp.hdr[7]);
continue;
}
vpninfo->ssl_times.last_rx = time(NULL);