diff options
Diffstat (limited to 'svr-tcpfwd.c')
| -rw-r--r-- | svr-tcpfwd.c | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/svr-tcpfwd.c b/svr-tcpfwd.c new file mode 100644 index 0000000..499ee46 --- /dev/null +++ b/svr-tcpfwd.c @@ -0,0 +1,196 @@ +#include "includes.h" +#include "ssh.h" +#include "tcp-accept.h" +#include "tcp-connect.h" +#include "dbutil.h" +#include "session.h" +#include "buffer.h" +#include "packet.h" +#include "listener.h" +#include "runopts.h" + +#ifndef DISABLE_SVR_REMOTETCPFWD + +static void send_msg_request_success(); +static void send_msg_request_failure(); +static int svr_cancelremotetcp(); +static int svr_remotetcpreq(); + + +const struct ChanType svr_chan_tcpdirect = { + 1, /* sepfds */ + "direct-tcpip", + newtcpdirect, /* init */ + NULL, /* checkclose */ + NULL, /* reqhandler */ + NULL /* closehandler */ +}; + +static const struct ChanType svr_chan_tcpremote = { + 1, /* sepfds */ + "forwarded-tcpip", + NULL, + NULL, + NULL, + NULL +}; + +/* At the moment this is completely used for tcp code (with the name reflecting + * that). If new request types are added, this should be replaced with code + * similar to the request-switching in chansession.c */ +void recv_msg_global_request_remotetcp() { + + unsigned char* reqname = NULL; + unsigned int namelen; + unsigned int wantreply = 0; + int ret = DROPBEAR_FAILURE; + + TRACE(("enter recv_msg_global_request_remotetcp")); + + if (opts.noremotetcp) { + TRACE(("leave recv_msg_global_request_remotetcp: remote tcp forwarding disabled")); + goto out; + } + + reqname = buf_getstring(ses.payload, &namelen); + wantreply = buf_getbyte(ses.payload); + + if (namelen > MAXNAMLEN) { + TRACE(("name len is wrong: %d", namelen)); + goto out; + } + + if (strcmp("tcpip-forward", reqname) == 0) { + ret = svr_remotetcpreq(); + } else if (strcmp("cancel-tcpip-forward", reqname) == 0) { + ret = svr_cancelremotetcp(); + } else { + TRACE(("reqname isn't tcpip-forward: '%s'", reqname)); + } + +out: + if (wantreply) { + if (ret == DROPBEAR_SUCCESS) { + send_msg_request_success(); + } else { + send_msg_request_failure(); + } + } + + m_free(reqname); + + TRACE(("leave recv_msg_global_request")); +} + + +static void send_msg_request_success() { + + CHECKCLEARTOWRITE(); + buf_putbyte(ses.writepayload, SSH_MSG_REQUEST_SUCCESS); + encrypt_packet(); + +} + +static void send_msg_request_failure() { + + CHECKCLEARTOWRITE(); + buf_putbyte(ses.writepayload, SSH_MSG_REQUEST_FAILURE); + encrypt_packet(); + +} + +static int matchtcp(void* typedata1, void* typedata2) { + + const struct TCPListener *info1 = (struct TCPListener*)typedata1; + const struct TCPListener *info2 = (struct TCPListener*)typedata2; + + return (info1->port == info2->port) + && (info1->chantype == info2->chantype) + && (strcmp(info1->addr, info2->addr) == 0); +} + +static int svr_cancelremotetcp() { + + int ret = DROPBEAR_FAILURE; + unsigned char * bindaddr = NULL; + unsigned int addrlen; + unsigned int port; + struct Listener * listener = NULL; + struct TCPListener tcpinfo; + + TRACE(("enter cancelremotetcp")); + + bindaddr = buf_getstring(ses.payload, &addrlen); + if (addrlen > MAX_IP_LEN) { + TRACE(("addr len too long: %d", addrlen)); + goto out; + } + + port = buf_getint(ses.payload); + + tcpinfo.addr = bindaddr; + tcpinfo.port = port; + listener = get_listener(CHANNEL_ID_TCPFORWARDED, &tcpinfo, matchtcp); + if (listener) { + remove_listener( listener ); + ret = DROPBEAR_SUCCESS; + } + +out: + m_free(bindaddr); + TRACE(("leave cancelremotetcp")); + return ret; +} + +static int svr_remotetcpreq() { + + int ret = DROPBEAR_FAILURE; + unsigned char * bindaddr = NULL; + unsigned int addrlen; + struct TCPListener *tcpinfo = NULL; + unsigned int port; + + TRACE(("enter remotetcpreq")); + + bindaddr = buf_getstring(ses.payload, &addrlen); + if (addrlen > MAX_IP_LEN) { + TRACE(("addr len too long: %d", addrlen)); + goto out; + } + + port = buf_getint(ses.payload); + + if (port == 0) { + dropbear_log(LOG_INFO, "Server chosen tcpfwd ports are unsupported"); + goto out; + } + + if (port < 1 || port > 65535) { + TRACE(("invalid port: %d", port)); + goto out; + } + + if (!ses.allowprivport && port < IPPORT_RESERVED) { + TRACE(("can't assign port < 1024 for non-root")); + goto out; + } + + tcpinfo = (struct TCPListener*)m_malloc(sizeof(struct TCPListener)); + tcpinfo->addr = bindaddr; + tcpinfo->port = port; + tcpinfo->localport = -1; + tcpinfo->chantype = &svr_chan_tcpremote; + + ret = listen_tcpfwd(tcpinfo); + +out: + if (ret == DROPBEAR_FAILURE) { + /* we only free it if a listener wasn't created, since the listener + * has to remember it if it's to be cancelled */ + m_free(tcpinfo->addr); + m_free(tcpinfo); + } + TRACE(("leave remotetcpreq")); + return ret; +} +#endif |