- markus@cvs.openbsd.org 2001/03/16 19:06:30
[auth-options.c channels.c channels.h serverloop.c session.c]
implement "permitopen" key option, restricts -L style forwarding to
to specified host:port pairs. based on work by harlan@genua.de
diff --git a/channels.c b/channels.c
index bb872dc..941556a 100644
--- a/channels.c
+++ b/channels.c
@@ -40,7 +40,7 @@
*/
#include "includes.h"
-RCSID("$OpenBSD: channels.c,v 1.98 2001/03/04 17:42:28 millert Exp $");
+RCSID("$OpenBSD: channels.c,v 1.99 2001/03/16 19:06:29 markus Exp $");
#include <openssl/rsa.h>
#include <openssl/dsa.h>
@@ -141,18 +141,6 @@
have_hostname_in_open = hostname_in_open;
}
-/*
- * Permits opening to any host/port in SSH_MSG_PORT_OPEN. This is usually
- * called by the server, because the user could connect to any port anyway,
- * and the server has no way to know but to trust the client anyway.
- */
-
-void
-channel_permit_all_opens()
-{
- all_opens_permitted = 1;
-}
-
/* lookup channel by id */
Channel *
@@ -1791,9 +1779,47 @@
xfree(hostname);
}
-/* XXX move to aux.c */
+/*
+ * Permits opening to any host/port if permitted_opens[] is empty. This is
+ * usually called by the server, because the user could connect to any port
+ * anyway, and the server has no way to know but to trust the client anyway.
+ */
+void
+channel_permit_all_opens()
+{
+ if (num_permitted_opens == 0)
+ all_opens_permitted = 1;
+}
+
+void
+channel_add_permitted_opens(char *host, int port)
+{
+ if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
+ fatal("channel_request_remote_forwarding: too many forwards");
+ debug("allow port forwarding to host %s port %d", host, port);
+
+ permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
+ permitted_opens[num_permitted_opens].port_to_connect = port;
+ num_permitted_opens++;
+
+ all_opens_permitted = 0;
+}
+
+void
+channel_clear_permitted_opens(void)
+{
+ int i;
+
+ for (i = 0; i < num_permitted_opens; i++)
+ xfree(permitted_opens[i].host_to_connect);
+ num_permitted_opens = 0;
+
+}
+
+
+/* return socket to remote host, port */
int
-channel_connect_to(const char *host, u_short host_port)
+connect_to(const char *host, u_short port)
{
struct addrinfo hints, *ai, *aitop;
char ntop[NI_MAXHOST], strport[NI_MAXSERV];
@@ -1803,9 +1829,10 @@
memset(&hints, 0, sizeof(hints));
hints.ai_family = IPv4or6;
hints.ai_socktype = SOCK_STREAM;
- snprintf(strport, sizeof strport, "%d", host_port);
+ snprintf(strport, sizeof strport, "%d", port);
if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
- error("%.100s: unknown host (%s)", host, gai_strerror(gaierr));
+ error("connect_to %.100s: unknown host (%s)", host,
+ gai_strerror(gaierr));
return -1;
}
for (ai = aitop; ai; ai = ai->ai_next) {
@@ -1813,10 +1840,9 @@
continue;
if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
- error("channel_connect_to: getnameinfo failed");
+ error("connect_to: getnameinfo failed");
continue;
}
- /* Create the socket. */
sock = socket(ai->ai_family, SOCK_STREAM, 0);
if (sock < 0) {
error("socket: %.100s", strerror(errno));
@@ -1824,10 +1850,9 @@
}
if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0)
fatal("connect_to: F_SETFL: %s", strerror(errno));
- /* Connect to the host/port. */
if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
errno != EINPROGRESS) {
- error("connect %.100s port %s: %.100s", ntop, strport,
+ error("connect_to %.100s port %s: %.100s", ntop, strport,
strerror(errno));
close(sock);
continue; /* fail -- try next */
@@ -1837,19 +1862,21 @@
}
freeaddrinfo(aitop);
if (!ai) {
- error("connect %.100s port %d: failed.", host, host_port);
+ error("connect_to %.100s port %d: failed.", host, port);
return -1;
}
/* success */
return sock;
}
+
int
channel_connect_by_listen_adress(u_short listen_port)
{
int i;
+
for (i = 0; i < num_permitted_opens; i++)
if (permitted_opens[i].listen_port == listen_port)
- return channel_connect_to(
+ return connect_to(
permitted_opens[i].host_to_connect,
permitted_opens[i].port_to_connect);
error("WARNING: Server requests forwarding for unknown listen_port %d",
@@ -1857,6 +1884,28 @@
return -1;
}
+/* Check if connecting to that port is permitted and connect. */
+int
+channel_connect_to(const char *host, u_short port)
+{
+ int i, permit;
+
+ permit = all_opens_permitted;
+ if (!permit) {
+ for (i = 0; i < num_permitted_opens; i++)
+ if (permitted_opens[i].port_to_connect == port &&
+ strcmp(permitted_opens[i].host_to_connect, host) == 0)
+ permit = 1;
+
+ }
+ if (!permit) {
+ log("Received request to connect to host %.100s port %d, "
+ "but the request was denied.", host, port);
+ return -1;
+ }
+ return connect_to(host, port);
+}
+
/*
* This is called after receiving PORT_OPEN message. This attempts to
* connect to the given host:port, and sends back CHANNEL_OPEN_CONFIRMATION
@@ -1868,55 +1917,25 @@
{
u_short host_port;
char *host, *originator_string;
- int remote_channel, sock = -1, newch, i, denied;
- u_int host_len, originator_len;
+ int remote_channel, sock = -1, newch;
- /* Get remote channel number. */
remote_channel = packet_get_int();
-
- /* Get host name to connect to. */
- host = packet_get_string(&host_len);
-
- /* Get port to connect to. */
+ host = packet_get_string(NULL);
host_port = packet_get_int();
- /* Get remote originator name. */
if (have_hostname_in_open) {
- originator_string = packet_get_string(&originator_len);
- originator_len += 4; /* size of packet_int */
+ originator_string = packet_get_string(NULL);
} else {
originator_string = xstrdup("unknown (remote did not supply name)");
- originator_len = 0; /* no originator supplied */
}
-
- packet_integrity_check(plen,
- 4 + 4 + host_len + 4 + originator_len, SSH_MSG_PORT_OPEN);
-
- /* Check if opening that port is permitted. */
- denied = 0;
- if (!all_opens_permitted) {
- /* Go trough all permitted ports. */
- for (i = 0; i < num_permitted_opens; i++)
- if (permitted_opens[i].port_to_connect == host_port &&
- strcmp(permitted_opens[i].host_to_connect, host) == 0)
- break;
-
- /* Check if we found the requested port among those permitted. */
- if (i >= num_permitted_opens) {
- /* The port is not permitted. */
- log("Received request to connect to %.100s:%d, but the request was denied.",
- host, host_port);
- denied = 1;
- }
- }
- sock = denied ? -1 : channel_connect_to(host, host_port);
- if (sock > 0) {
- /* Allocate a channel for this connection. */
+ packet_done();
+ sock = channel_connect_to(host, host_port);
+ if (sock != -1) {
newch = channel_allocate(SSH_CHANNEL_CONNECTING,
sock, originator_string);
-/*XXX delay answer? */
channels[newch].remote_id = remote_channel;
+ /*XXX delay answer? */
packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
packet_put_int(remote_channel);
packet_put_int(newch);