X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/cbe2d68fd7c7c7bac692b3a2d200a5d2429ab201..79bf227ba7ba02e32ac710621b672e2789f9ef50:/portfwd.c diff --git a/portfwd.c b/portfwd.c index f73d22cc..b95e5acd 100644 --- a/portfwd.c +++ b/portfwd.c @@ -107,7 +107,12 @@ static int pfd_receive(Plug plug, int urgent, char *data, int len) struct PFwdPrivate *pr = (struct PFwdPrivate *) plug; if (pr->dynamic) { while (len--) { + /* + * Throughout SOCKS negotiation, "hostname" is re-used as a + * random protocol buffer with "port" storing the length. + */ if (pr->port >= lenof(pr->hostname)) { + /* Request too long. */ if ((pr->dynamic >> 12) == 4) { /* Send back a SOCKS 4 error before closing. */ char data[8]; @@ -133,6 +138,7 @@ static int pfd_receive(Plug plug, int urgent, char *data, int len) pr->dynamic = 0x4000; if (pr->port < 2) continue;/* don't have command code yet */ if (pr->hostname[1] != 1) { + /* Not CONNECT. */ /* Send back a SOCKS 4 error before closing. */ char data[8]; memset(data, 0, sizeof(data)); @@ -141,9 +147,9 @@ static int pfd_receive(Plug plug, int urgent, char *data, int len) pfd_close(pr->s); return 1; } - if (pr->port < 8) continue; /* haven't started username */ + if (pr->port <= 8) continue; /* haven't started user/hostname */ if (pr->hostname[pr->port-1] != 0) - continue; /* haven't _finished_ username */ + continue; /* haven't _finished_ user/hostname */ /* * Now we have a full SOCKS 4 request. Check it to * see if it's a SOCKS 4A request. @@ -165,7 +171,7 @@ static int pfd_receive(Plug plug, int urgent, char *data, int len) pr->hostname[0] = 0; /* reply version code */ pr->hostname[1] = 90; /* request granted */ sk_write(pr->s, pr->hostname, 8); - len= pr->port; + len= pr->port - 8; pr->port = GET_16BIT_MSB_FIRST(pr->hostname+2); memmove(pr->hostname, pr->hostname + 8, len); goto connect; @@ -220,7 +226,23 @@ static int pfd_receive(Plug plug, int urgent, char *data, int len) } if (pr->dynamic == 0x5001) { + /* + * We're receiving a SOCKS request. + */ + unsigned char reply[10]; /* SOCKS5 atyp=1 reply */ int atype, alen = 0; + + /* + * Pre-fill reply packet. + * In all cases, we set BND.{HOST,ADDR} to 0.0.0.0:0 + * (atyp=1) in the reply; if we succeed, we don't know + * the right answers, and if we fail, they should be + * ignored. + */ + memset(reply, 0, lenof(reply)); + reply[0] = 5; /* VER */ + reply[3] = 1; /* ATYP = 1 (IPv4, 0.0.0.0:0) */ + if (pr->port < 6) continue; atype = (unsigned char)pr->hostname[3]; if (atype == 1) /* IPv4 address */ @@ -231,9 +253,9 @@ static int pfd_receive(Plug plug, int urgent, char *data, int len) alen = 1 + (unsigned char)pr->hostname[4]; if (pr->port < 6 + alen) continue; if (pr->hostname[1] != 1 || pr->hostname[2] != 0) { - pr->hostname[1] = 1; /* generic failure */ - pr->hostname[2] = 0; /* reserved */ - sk_write(pr->s, pr->hostname, pr->port); + /* Not CONNECT or reserved field nonzero - error */ + reply[1] = 1; /* generic failure */ + sk_write(pr->s, (char *) reply, lenof(reply)); pfd_close(pr->s); return 1; } @@ -243,8 +265,8 @@ static int pfd_receive(Plug plug, int urgent, char *data, int len) */ pr->port = GET_16BIT_MSB_FIRST(pr->hostname+4+alen); if (atype == 1) { - pr->hostname[1] = 0; /* succeeded */ - sk_write(pr->s, pr->hostname, alen + 6); + /* REP=0 (success) already */ + sk_write(pr->s, (char *) reply, lenof(reply)); sprintf(pr->hostname, "%d.%d.%d.%d", (unsigned char)pr->hostname[4], (unsigned char)pr->hostname[5], @@ -252,8 +274,8 @@ static int pfd_receive(Plug plug, int urgent, char *data, int len) (unsigned char)pr->hostname[7]); goto connect; } else if (atype == 3) { - pr->hostname[1] = 0; /* succeeded */ - sk_write(pr->s, pr->hostname, alen + 6); + /* REP=0 (success) already */ + sk_write(pr->s, (char *) reply, lenof(reply)); memmove(pr->hostname, pr->hostname + 5, alen-1); pr->hostname[alen-1] = '\0'; goto connect; @@ -261,14 +283,14 @@ static int pfd_receive(Plug plug, int urgent, char *data, int len) /* * Unknown address type. (FIXME: support IPv6!) */ - pr->hostname[1] = 8; /* atype not supported */ - sk_write(pr->s, pr->hostname, pr->port); + reply[1] = 8; /* atype not supported */ + sk_write(pr->s, (char *) reply, lenof(reply)); pfd_close(pr->s); - return 1; + return 1; } } } - + /* * If we get here without either having done `continue' * or `goto connect', it must be because there is no @@ -350,8 +372,10 @@ const char *pfd_newconnect(Socket *s, char *hostname, int port, * Try to find host. */ addr = name_lookup(hostname, port, &dummy_realhost, cfg); - if ((err = sk_addr_error(addr)) != NULL) + if ((err = sk_addr_error(addr)) != NULL) { + sk_addr_free(addr); return err; + } /* * Open socket. @@ -366,14 +390,13 @@ const char *pfd_newconnect(Socket *s, char *hostname, int port, pr->dynamic = 0; pr->s = *s = new_connection(addr, dummy_realhost, port, - 0, 1, 0, (Plug) pr, cfg); + 0, 1, 0, 0, (Plug) pr, cfg); if ((err = sk_socket_error(*s)) != NULL) { sfree(pr); return err; } sk_set_private_ptr(*s, pr); - sk_addr_free(addr); return NULL; } @@ -381,7 +404,7 @@ const char *pfd_newconnect(Socket *s, char *hostname, int port, called when someone connects to the local port */ -static int pfd_accepting(Plug p, void *sock) +static int pfd_accepting(Plug p, OSSocket sock) { static const struct plug_function_table fn_table = { pfd_closing, @@ -414,7 +437,7 @@ static int pfd_accepting(Plug p, void *sock) if (org->dynamic) { pr->dynamic = 1; - pr->port = 0; /* hostname buffer is so far empty */ + pr->port = 0; /* "hostname" buffer is so far empty */ sk_set_frozen(s, 0); /* we want to receive SOCKS _now_! */ } else { pr->dynamic = 0;