SSLproxy/tests/testproxy/lp/prototcp.c
2020-05-04 12:16:03 +03:00

644 lines
19 KiB
C

/*-
* SSLsplit - transparent SSL/TLS interception
* https://www.roe.ch/SSLsplit
*
* Copyright (c) 2009-2019, Daniel Roethlisberger <daniel@roe.ch>.
* Copyright (c) 2017-2020, Soner Tari <sonertari@gmail.com>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "prototcp.h"
#include "sys.h"
#include <sys/param.h>
#include <string.h>
#include <errno.h>
#ifdef __linux__
#include <glob.h>
#endif /* __linux__ */
/*
* Set up a bufferevent structure for either a dst or src connection,
* optionally with or without SSL. Sets all callbacks, enables read
* and write events, but does not call bufferevent_socket_connect().
*
* For dst connections, pass -1 as fd. Pass a pointer to an initialized
* SSL struct as ssl if the connection should use SSL.
*
* Returns pointer to initialized bufferevent structure, as returned
* by bufferevent_socket_new() or bufferevent_openssl_socket_new().
*/
static struct bufferevent * NONNULL(1)
prototcp_bufferevent_setup(pxy_conn_ctx_t *ctx, evutil_socket_t fd)
{
log_finest_va("ENTER, fd=%d", fd);
struct bufferevent *bev = bufferevent_socket_new(ctx->thr->evbase, fd, BEV_OPT_DEFER_CALLBACKS|BEV_OPT_THREADSAFE);
if (!bev) {
log_err_level(LOG_CRIT, "Error creating bufferevent socket");
return NULL;
}
return bev;
}
/*
* Free bufferenvent and close underlying socket properly.
*/
static void
prototcp_bufferevent_free_and_close_fd(struct bufferevent *bev, UNUSED pxy_conn_ctx_t *ctx)
{
evutil_socket_t fd = bufferevent_getfd(bev);
log_finer_va("in=%zu, out=%zu, fd=%d", evbuffer_get_length(bufferevent_get_input(bev)), evbuffer_get_length(bufferevent_get_output(bev)), fd);
bufferevent_free(bev);
evutil_closesocket(fd);
}
static int NONNULL(1)
prototcp_setup_src(pxy_conn_ctx_t *ctx)
{
ctx->src.bev = prototcp_bufferevent_setup(ctx, ctx->fd);
if (!ctx->src.bev) {
log_err_level_printf(LOG_CRIT, "Error creating src bufferevent\n");
pxy_conn_term(ctx, 1);
return -1;
}
ctx->src.free = prototcp_bufferevent_free_and_close_fd;
return 0;
}
static int NONNULL(1)
prototcp_setup_dst(pxy_conn_ctx_t *ctx)
{
ctx->dst.bev = prototcp_bufferevent_setup(ctx, -1);
if (!ctx->dst.bev) {
log_err_level_printf(LOG_CRIT, "Error creating parent dst\n");
pxy_conn_term(ctx, 1);
return -1;
}
ctx->dst.free = prototcp_bufferevent_free_and_close_fd;
return 0;
}
#if defined(__APPLE__) || defined(__FreeBSD__)
#define getdtablecount() 0
/*
* Copied from:
* opensmtpd-201801101641p1/openbsd-compat/imsg.c
*
* Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
static int
available_fds(unsigned int n)
{
unsigned int i;
int ret, fds[256];
if (n > (sizeof(fds)/sizeof(fds[0])))
return -1;
ret = 0;
for (i = 0; i < n; i++) {
fds[i] = -1;
if ((fds[i] = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
ret = -1;
break;
}
}
for (i = 0; i < n && fds[i] >= 0; i++)
close(fds[i]);
return ret;
}
#endif /* __APPLE__ || __FreeBSD__ */
#ifdef __linux__
/*
* Copied from:
* https://github.com/tmux/tmux/blob/master/compat/getdtablecount.c
*
* Copyright (c) 2017 Nicholas Marriott <nicholas.marriott@gmail.com>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
* IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
int
getdtablecount()
{
char path[PATH_MAX];
glob_t g;
int n = 0;
if (snprintf(path, sizeof path, "/proc/%ld/fd/*", (long)getpid()) < 0) {
log_err_level_printf(LOG_CRIT, "snprintf overflow\n");
return 0;
}
if (glob(path, 0, NULL, &g) == 0)
n = g.gl_pathc;
globfree(&g);
return n;
}
#endif /* __linux__ */
/*
* Check if we are out of file descriptors to close the conn, or else libevent will crash us
* @attention We cannot guess the number of children in a connection at conn setup time. So, FD_RESERVE is just a ball park figure.
* But what if a connection passes the check below, but eventually tries to create more children than FD_RESERVE allows for? This will crash us the same.
* Beware, this applies to all current conns, not just the last connection setup.
* For example, 20x conns pass the check below before creating any children, at which point we reach the last FD_RESERVE fds,
* then they all start creating children, which crashes us again.
* So, no matter how large an FD_RESERVE we choose, there will always be a risk of running out of fds, if we check the number of fds during parent conn setup only.
* If we are left with less than FD_RESERVE fds, we should not create more children than FD_RESERVE allows for either.
* Therefore, we check if we are out of fds in pxy_listener_acceptcb_child() and close the conn there too.
* @attention These checks are expected to slow us further down, but it is critical to avoid a crash in case we run out of fds.
*/
static int
check_fd_usage(
#ifdef DEBUG_PROXY
pxy_conn_ctx_t *ctx
#endif /* DEBUG_PROXY */
)
{
int dtable_count = getdtablecount();
log_finer_va("descriptor_table_size=%d, dtablecount=%d, reserve=%d", descriptor_table_size, dtable_count, FD_RESERVE);
if (dtable_count + FD_RESERVE >= descriptor_table_size) {
goto out;
}
#if defined(__APPLE__) || defined(__FreeBSD__)
if (available_fds(FD_RESERVE) == -1) {
goto out;
}
#endif /* __APPLE__ || __FreeBSD__ */
return 0;
out:
errno = EMFILE;
log_err_level_printf(LOG_CRIT, "Out of file descriptors\n");
return -1;
}
void
prototcp_connect(UNUSED evutil_socket_t fd, UNUSED short what, void *arg)
{
pxy_conn_ctx_t *ctx = arg;
log_finest("ENTER");
event_free(ctx->ev);
ctx->ev = NULL;
pxy_thr_attach(ctx);
if (check_fd_usage(
#ifdef DEBUG_PROXY
ctx
#endif /* DEBUG_PROXY */
) == -1) {
goto out;
}
if (sys_sockaddr_str((struct sockaddr *)&ctx->srcaddr, ctx->srcaddrlen, &ctx->srchost_str, &ctx->srcport_str) != 0) {
log_err_level_printf(LOG_CRIT, "Aborting connection setup (out of memory)!\n");
goto out;
}
log_finest_va("srcaddr= [%s]:%s", ctx->srchost_str, ctx->srcport_str);
if (prototcp_setup_src(ctx) == -1) {
goto out;
}
if (prototcp_setup_dst(ctx) == -1) {
goto out;
}
bufferevent_setcb(ctx->src.bev, pxy_bev_readcb, pxy_bev_writecb, pxy_bev_eventcb, ctx);
bufferevent_setcb(ctx->dst.bev, pxy_bev_readcb, pxy_bev_writecb, pxy_bev_eventcb, ctx);
log_finer("Enabling src");
// Now open the gates
bufferevent_enable(ctx->src.bev, EV_READ|EV_WRITE);
return;
out:
evutil_closesocket(ctx->fd);
pxy_conn_free(ctx, 1);
}
static int
prototcp_parse_sslproxy_line(char *line, pxy_conn_ctx_t *ctx)
{
#define MAX_IPADDR_LEN 45
#define MAX_PORT_LEN 5
// SSLproxy: [127.0.0.1]:34649,[192.168.3.24]:47286,[74.125.206.108]:465,s,soner
if (!strncasecmp(line, "SSLproxy:", 9)) {
if (OPTS_DEBUG(ctx->opts)) {
log_dbg_printf("%s\n", line);
}
// The checks here cannot cover all possible error conditions
// But we should at least avoid crashes, for example caused by passing NULL pointers to str*() functions
char *ip_start = strchr(line, '[');
if (!ip_start) {
log_err_level_printf(LOG_ERR, "Unable to find sslproxy ip_start: %s\n", line);
return -1;
}
ip_start++;
char *ip_end = strchr(ip_start, ']');
if (!ip_end) {
log_err_level_printf(LOG_ERR, "Unable to find sslproxy ip_end: %s\n", line);
return -1;
}
char *port_start = strchr(ip_end, ':');
if (!port_start) {
log_err_level_printf(LOG_ERR, "Unable to find sslproxy port_start: %s\n", line);
return -1;
}
port_start++;
char *port_end = strchr(port_start, ',');
if (!port_end) {
log_err_level_printf(LOG_ERR, "Unable to find sslproxy port_end: %s\n", line);
return -1;
}
int addr_len = ip_end - ip_start;
if (addr_len > MAX_IPADDR_LEN) {
log_err_level_printf(LOG_ERR, "sslproxy addr_len greater than MAX_IPADDR_LEN: %d\n", addr_len);
return -1;
}
// We can use addr_len for size restriction here, because we check it against MAX_IPADDR_LEN above
char addr[addr_len + 1];
strncpy(addr, ip_start, addr_len);
addr[addr_len] = '\0';
int port_len = port_end - port_start;
if (port_len > MAX_PORT_LEN) {
log_err_level_printf(LOG_ERR, "sslproxy port_len greater than MAX_PORT_LEN: %d\n", port_len);
return -1;
}
// We can use port_len for size restriction here, because we check it against MAX_PORT_LEN above
char port[port_len + 1];
strncpy(port, port_start, port_len);
port[port_len] = '\0';
if (sys_sockaddr_parse(&ctx->dstaddr,
&ctx->dstaddrlen,
addr, port,
sys_get_af(addr),
EVUTIL_AI_PASSIVE) == -1) {
log_err_level_printf(LOG_ERR, "Cannot convert sslproxy addr to sockaddr: [%s]:%s\n", addr, port);
return -1;
}
if (OPTS_DEBUG(ctx->opts)) {
log_dbg_printf("Connecting to [%s]:%s\n", addr, port);
ctx->dsthost_str = strdup(addr);
ctx->dstport_str = strdup(port);
if (!ctx->dsthost_str || !ctx->dstport_str) {
log_err_level_printf(LOG_ERR, "Cannot dup addr or port: [%s]:%s\n", addr, port);
return -1;
}
}
ctx->seen_sslproxy_line = 1;
}
return 0;
}
static void NONNULL(1,2)
prototcp_bev_readcb_src(struct bufferevent *bev, pxy_conn_ctx_t *ctx)
{
log_finest_va("ENTER, size=%zu", evbuffer_get_length(bufferevent_get_input(bev)));
struct evbuffer *inbuf = bufferevent_get_input(bev);
struct evbuffer *outbuf = bufferevent_get_output(ctx->dst.bev);
if (!ctx->seen_sslproxy_line) {
char *line;
while (!ctx->seen_sslproxy_line && (line = evbuffer_readln(inbuf, NULL, EVBUFFER_EOL_CRLF))) {
log_finest_va("%s", line);
if (prototcp_parse_sslproxy_line(line, ctx) == -1) {
free(line);
pxy_conn_term(ctx, 1);
return;
}
if (ctx->seen_sslproxy_line) {
/* initiate connection */
bufferevent_enable(ctx->dst.bev, EV_READ|EV_WRITE);
if (bufferevent_socket_connect(ctx->dst.bev, (struct sockaddr *)&ctx->dstaddr, ctx->dstaddrlen) == -1) {
log_err_level(LOG_CRIT, "bufferevent_socket_connect for dst failed");
}
}
evbuffer_add_printf(outbuf, "%s\r\n", line);
free(line);
}
if (evbuffer_get_length(inbuf) == 0) {
goto out;
}
} else {
if (ctx->dst.closed) {
pxy_discard_inbuf(bev);
return;
}
}
evbuffer_add_buffer(outbuf, inbuf);
out:
pxy_try_set_watermark(bev, ctx, ctx->dst.bev);
}
static void NONNULL(1)
prototcp_bev_readcb_dst(struct bufferevent *bev, pxy_conn_ctx_t *ctx)
{
log_finest_va("ENTER, size=%zu", evbuffer_get_length(bufferevent_get_input(bev)));
if (!ctx->dst_connected) {
log_err_level_printf(LOG_CRIT, "prototcp_bev_readcb_dst: readcb called when not connected - aborting.\n");
log_exceptcb();
return;
}
if (ctx->src.closed) {
pxy_discard_inbuf(bev);
return;
}
evbuffer_add_buffer(bufferevent_get_output(ctx->src.bev), bufferevent_get_input(bev));
pxy_try_set_watermark(bev, ctx, ctx->src.bev);
}
static int NONNULL(1,2)
prototcp_connect_conn_end(struct bufferevent *bev, pxy_conn_ctx_t *ctx)
{
log_fine("writecb before connected");
// @attention Sometimes writecb fires but not connectcb, especially if the listener cb is not finished yet,
// so as a workaround if we don't call the connectcb here, the conn would stall.
// This issue seems to happen if we enable EV_WRITE before we get BEV_EVENT_CONNECTED. Apparently, EV_WRITE consumes BEV_EVENT_CONNECTED.
// So we should enable EV_WRITE after we get BEV_EVENT_CONNECTED, e.g. in the connectcb, if possible at all.
ctx->protoctx->bev_eventcb(bev, BEV_EVENT_CONNECTED, ctx);
return pxy_bev_eventcb_postexec_logging_and_stats(bev, BEV_EVENT_CONNECTED, ctx);
}
static void NONNULL(1)
prototcp_bev_writecb_src(struct bufferevent *bev, pxy_conn_ctx_t *ctx)
{
log_finest("ENTER");
if (!ctx->src_connected) {
if (prototcp_connect_conn_end(bev, ctx) == -1) {
return;
}
}
if (ctx->dst.closed) {
if (pxy_try_close_conn_end(&ctx->src, ctx) == 1) {
log_finest("dst.closed, terminate conn");
pxy_conn_term(ctx, 1);
}
return;
}
pxy_try_unset_watermark(bev, ctx, &ctx->dst);
}
static void NONNULL(1)
prototcp_bev_writecb_dst(struct bufferevent *bev, pxy_conn_ctx_t *ctx)
{
log_finest("ENTER");
if (!ctx->dst_connected) {
if (prototcp_connect_conn_end(bev, ctx) == -1) {
return;
}
}
if (ctx->src.closed) {
if (pxy_try_close_conn_end(&ctx->dst, ctx) == 1) {
log_finest("src.closed, terminate conn");
pxy_conn_term(ctx, 0);
}
return;
}
pxy_try_unset_watermark(bev, ctx, &ctx->src);
}
static void NONNULL(1,2)
prototcp_bev_eventcb_connected_src(UNUSED struct bufferevent *bev, UNUSED pxy_conn_ctx_t *ctx)
{
log_finest("ENTER");
ctx->src_connected = 1;
}
static void NONNULL(1,2)
prototcp_bev_eventcb_connected_dst(UNUSED struct bufferevent *bev, pxy_conn_ctx_t *ctx)
{
log_finest("ENTER");
ctx->dst_connected = 1;
}
static void NONNULL(1,2)
prototcp_bev_eventcb_eof_src(struct bufferevent *bev, pxy_conn_ctx_t *ctx)
{
#ifdef DEBUG_PROXY
log_finest("ENTER");
pxy_log_dbg_evbuf_info(ctx, &ctx->src, &ctx->dst);
#endif /* DEBUG_PROXY */
if (!ctx->src_connected) {
log_err_level(LOG_WARNING, "EOF on connection before connection establishment");
ctx->dst.closed = 1;
} else if (!ctx->dst.closed) {
log_finest("!dst->closed, terminate conn");
if (pxy_try_consume_last_input(bev, ctx) == -1) {
return;
}
pxy_try_close_conn_end(&ctx->dst, ctx);
}
pxy_try_disconnect(ctx, &ctx->src, &ctx->dst, 1);
}
static void NONNULL(1,2)
prototcp_bev_eventcb_eof_dst(struct bufferevent *bev, pxy_conn_ctx_t *ctx)
{
#ifdef DEBUG_PROXY
log_finest("ENTER");
pxy_log_dbg_evbuf_info(ctx, &ctx->dst, &ctx->src);
#endif /* DEBUG_PROXY */
if (!ctx->dst_connected) {
log_err_level(LOG_WARNING, "EOF on connection before connection establishment");
ctx->src.closed = 1;
} else if (!ctx->src.closed) {
log_finest("!src->closed, terminate conn");
if (pxy_try_consume_last_input(bev, ctx) == -1) {
return;
}
pxy_try_close_conn_end(&ctx->src, ctx);
}
pxy_try_disconnect(ctx, &ctx->dst, &ctx->src, 0);
}
static void NONNULL(1,2)
prototcp_bev_eventcb_error_src(UNUSED struct bufferevent *bev, pxy_conn_ctx_t *ctx)
{
log_fine("BEV_EVENT_ERROR");
if (!ctx->src_connected) {
ctx->dst.closed = 1;
} else if (!ctx->dst.closed) {
pxy_try_close_conn_end(&ctx->dst, ctx);
}
pxy_try_disconnect(ctx, &ctx->src, &ctx->dst, 1);
}
static void NONNULL(1,2)
prototcp_bev_eventcb_error_dst(UNUSED struct bufferevent *bev, pxy_conn_ctx_t *ctx)
{
log_fine("BEV_EVENT_ERROR");
if (!ctx->dst_connected) {
ctx->src.closed = 1;
} else if (!ctx->src.closed) {
pxy_try_close_conn_end(&ctx->src, ctx);
}
pxy_try_disconnect(ctx, &ctx->dst, &ctx->src, 0);
}
static void NONNULL(1,3)
prototcp_bev_eventcb_src(struct bufferevent *bev, short events, pxy_conn_ctx_t *ctx)
{
if (events & BEV_EVENT_CONNECTED) {
prototcp_bev_eventcb_connected_src(bev, ctx);
} else if (events & BEV_EVENT_EOF) {
prototcp_bev_eventcb_eof_src(bev, ctx);
} else if (events & BEV_EVENT_ERROR) {
prototcp_bev_eventcb_error_src(bev, ctx);
}
}
static void NONNULL(1)
prototcp_bev_eventcb_dst(struct bufferevent *bev, short events, pxy_conn_ctx_t *ctx)
{
if (events & BEV_EVENT_CONNECTED) {
prototcp_bev_eventcb_connected_dst(bev, ctx);
} else if (events & BEV_EVENT_EOF) {
prototcp_bev_eventcb_eof_dst(bev, ctx);
} else if (events & BEV_EVENT_ERROR) {
prototcp_bev_eventcb_error_dst(bev, ctx);
}
}
static void NONNULL(1)
prototcp_bev_readcb(struct bufferevent *bev, void *arg)
{
pxy_conn_ctx_t *ctx = arg;
if (bev == ctx->src.bev) {
prototcp_bev_readcb_src(bev, ctx);
} else if (bev == ctx->dst.bev) {
prototcp_bev_readcb_dst(bev, ctx);
} else {
log_err_printf("prototcp_bev_readcb: UNKWN conn end\n");
}
}
static void NONNULL(1)
prototcp_bev_writecb(struct bufferevent *bev, void *arg)
{
pxy_conn_ctx_t *ctx = arg;
if (bev == ctx->src.bev) {
prototcp_bev_writecb_src(bev, ctx);
} else if (bev == ctx->dst.bev) {
prototcp_bev_writecb_dst(bev, ctx);
} else {
log_err_printf("prototcp_bev_writecb: UNKWN conn end\n");
}
}
static void NONNULL(1)
prototcp_bev_eventcb(struct bufferevent *bev, short events, void *arg)
{
pxy_conn_ctx_t *ctx = arg;
if (bev == ctx->src.bev) {
prototcp_bev_eventcb_src(bev, events, ctx);
} else if (bev == ctx->dst.bev) {
prototcp_bev_eventcb_dst(bev, events, ctx);
} else {
log_err_printf("prototcp_bev_eventcb: UNKWN conn end\n");
}
}
protocol_t
prototcp_setup(pxy_conn_ctx_t *ctx)
{
ctx->protoctx->proto = PROTO_TCP;
ctx->protoctx->bev_readcb = prototcp_bev_readcb;
ctx->protoctx->bev_writecb = prototcp_bev_writecb;
ctx->protoctx->bev_eventcb = prototcp_bev_eventcb;
return PROTO_TCP;
}
/* vim: set noet ft=c: */