X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/51b2fb65e228f0a5a179429a48a4392da74de0c2..887035a593c8c0a1af853657c80046e17dc5581a:/ssh.c diff --git a/ssh.c b/ssh.c index 7470163d..31d4cc49 100644 --- a/ssh.c +++ b/ssh.c @@ -5,6 +5,7 @@ #include #include "putty.h" +#include "terminal.h" #include "tree234.h" #include "ssh.h" @@ -15,16 +16,25 @@ #define TRUE 1 #endif -/* uncomment this for packet level debugging */ -/* #define DUMP_PACKETS */ - #define logevent(s) { logevent(s); \ if ((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)) \ { fprintf(stderr, "%s\n", s); fflush(stderr); } } +/* logevent, only printf-formatted. */ +void logeventf(char *fmt, ...) +{ + va_list ap; + char stuff[200]; + + va_start(ap, fmt); + vsprintf(stuff, fmt, ap); + va_end(ap); + logevent(stuff); +} + #define bombout(msg) ( ssh_state = SSH_STATE_CLOSED, \ (s ? sk_close(s), s = NULL : 0), \ - connection_fatal msg ) + logeventf msg, connection_fatal msg ) #define SSH1_MSG_DISCONNECT 1 /* 0x1 */ #define SSH1_SMSG_PUBLIC_KEY 2 /* 0x2 */ @@ -95,6 +105,8 @@ #define SSH2_MSG_USERAUTH_BANNER 53 /* 0x35 */ #define SSH2_MSG_USERAUTH_PK_OK 60 /* 0x3c */ #define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ 60 /* 0x3c */ +#define SSH2_MSG_USERAUTH_INFO_REQUEST 60 /* 0x3c */ +#define SSH2_MSG_USERAUTH_INFO_RESPONSE 61 /* 0x3d */ #define SSH2_MSG_GLOBAL_REQUEST 80 /* 0x50 */ #define SSH2_MSG_REQUEST_SUCCESS 81 /* 0x51 */ #define SSH2_MSG_REQUEST_FAILURE 82 /* 0x52 */ @@ -110,6 +122,17 @@ #define SSH2_MSG_CHANNEL_SUCCESS 99 /* 0x63 */ #define SSH2_MSG_CHANNEL_FAILURE 100 /* 0x64 */ +/* + * Packet type contexts, so that ssh2_pkt_type can correctly decode + * the ambiguous type numbers back into the correct type strings. + */ +#define SSH2_PKTCTX_DHGROUP1 0x0001 +#define SSH2_PKTCTX_DHGEX 0x0002 +#define SSH2_PKTCTX_PUBLICKEY 0x0010 +#define SSH2_PKTCTX_PASSWORD 0x0020 +#define SSH2_PKTCTX_KBDINTER 0x0040 +#define SSH2_PKTCTX_AUTH_MASK 0x00F0 + #define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1 /* 0x1 */ #define SSH2_DISCONNECT_PROTOCOL_ERROR 2 /* 0x2 */ #define SSH2_DISCONNECT_KEY_EXCHANGE_FAILED 3 /* 0x3 */ @@ -157,6 +180,103 @@ static const char *const ssh2_disconnect_reasons[] = { */ #define BUG_CHOKES_ON_SSH1_IGNORE 1 #define BUG_SSH2_HMAC 2 +#define BUG_NEEDS_SSH1_PLAIN_PASSWORD 4 +#define BUG_CHOKES_ON_RSA 8 +#define BUG_SSH2_RSA_PADDING 16 +#define BUG_SSH2_DERIVEKEY 32 +#define BUG_SSH2_DH_GEX 64 + +static int ssh_pkt_ctx = 0; + +#define translate(x) if (type == x) return #x +#define translatec(x,ctx) if (type == x && (ssh_pkt_ctx & ctx)) return #x +char *ssh1_pkt_type(int type) +{ + translate(SSH1_MSG_DISCONNECT); + translate(SSH1_SMSG_PUBLIC_KEY); + translate(SSH1_CMSG_SESSION_KEY); + translate(SSH1_CMSG_USER); + translate(SSH1_CMSG_AUTH_RSA); + translate(SSH1_SMSG_AUTH_RSA_CHALLENGE); + translate(SSH1_CMSG_AUTH_RSA_RESPONSE); + translate(SSH1_CMSG_AUTH_PASSWORD); + translate(SSH1_CMSG_REQUEST_PTY); + translate(SSH1_CMSG_WINDOW_SIZE); + translate(SSH1_CMSG_EXEC_SHELL); + translate(SSH1_CMSG_EXEC_CMD); + translate(SSH1_SMSG_SUCCESS); + translate(SSH1_SMSG_FAILURE); + translate(SSH1_CMSG_STDIN_DATA); + translate(SSH1_SMSG_STDOUT_DATA); + translate(SSH1_SMSG_STDERR_DATA); + translate(SSH1_CMSG_EOF); + translate(SSH1_SMSG_EXIT_STATUS); + translate(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION); + translate(SSH1_MSG_CHANNEL_OPEN_FAILURE); + translate(SSH1_MSG_CHANNEL_DATA); + translate(SSH1_MSG_CHANNEL_CLOSE); + translate(SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION); + translate(SSH1_SMSG_X11_OPEN); + translate(SSH1_CMSG_PORT_FORWARD_REQUEST); + translate(SSH1_MSG_PORT_OPEN); + translate(SSH1_CMSG_AGENT_REQUEST_FORWARDING); + translate(SSH1_SMSG_AGENT_OPEN); + translate(SSH1_MSG_IGNORE); + translate(SSH1_CMSG_EXIT_CONFIRMATION); + translate(SSH1_CMSG_X11_REQUEST_FORWARDING); + translate(SSH1_CMSG_AUTH_RHOSTS_RSA); + translate(SSH1_MSG_DEBUG); + translate(SSH1_CMSG_REQUEST_COMPRESSION); + translate(SSH1_CMSG_AUTH_TIS); + translate(SSH1_SMSG_AUTH_TIS_CHALLENGE); + translate(SSH1_CMSG_AUTH_TIS_RESPONSE); + translate(SSH1_CMSG_AUTH_CCARD); + translate(SSH1_SMSG_AUTH_CCARD_CHALLENGE); + translate(SSH1_CMSG_AUTH_CCARD_RESPONSE); + return "unknown"; +} +char *ssh2_pkt_type(int type) +{ + translate(SSH2_MSG_DISCONNECT); + translate(SSH2_MSG_IGNORE); + translate(SSH2_MSG_UNIMPLEMENTED); + translate(SSH2_MSG_DEBUG); + translate(SSH2_MSG_SERVICE_REQUEST); + translate(SSH2_MSG_SERVICE_ACCEPT); + translate(SSH2_MSG_KEXINIT); + translate(SSH2_MSG_NEWKEYS); + translatec(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP1); + translatec(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP1); + translatec(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX); + translatec(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX); + translatec(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX); + translatec(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX); + translate(SSH2_MSG_USERAUTH_REQUEST); + translate(SSH2_MSG_USERAUTH_FAILURE); + translate(SSH2_MSG_USERAUTH_SUCCESS); + translate(SSH2_MSG_USERAUTH_BANNER); + translatec(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY); + translatec(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD); + translatec(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER); + translatec(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER); + translate(SSH2_MSG_GLOBAL_REQUEST); + translate(SSH2_MSG_REQUEST_SUCCESS); + translate(SSH2_MSG_REQUEST_FAILURE); + translate(SSH2_MSG_CHANNEL_OPEN); + translate(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); + translate(SSH2_MSG_CHANNEL_OPEN_FAILURE); + translate(SSH2_MSG_CHANNEL_WINDOW_ADJUST); + translate(SSH2_MSG_CHANNEL_DATA); + translate(SSH2_MSG_CHANNEL_EXTENDED_DATA); + translate(SSH2_MSG_CHANNEL_EOF); + translate(SSH2_MSG_CHANNEL_CLOSE); + translate(SSH2_MSG_CHANNEL_REQUEST); + translate(SSH2_MSG_CHANNEL_SUCCESS); + translate(SSH2_MSG_CHANNEL_FAILURE); + return "unknown"; +} +#undef translate +#undef translatec #define GET_32BIT(cp) \ (((unsigned long)(unsigned char)(cp)[0] << 24) | \ @@ -193,20 +313,55 @@ enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM }; extern char *x11_init(Socket *, char *, void *); extern void x11_close(Socket); -extern void x11_send(Socket, char *, int); +extern int x11_send(Socket, char *, int); extern void x11_invent_auth(char *, int, char *, int); +extern void x11_unthrottle(Socket s); +extern void x11_override_throttle(Socket s, int enable); + +extern char *pfd_newconnect(Socket * s, char *hostname, int port, void *c); +extern char *pfd_addforward(char *desthost, int destport, int port); +extern void pfd_close(Socket s); +extern int pfd_send(Socket s, char *data, int len); +extern void pfd_confirm(Socket s); +extern void pfd_unthrottle(Socket s); +extern void pfd_override_throttle(Socket s, int enable); + +static void ssh2_pkt_init(int pkt_type); +static void ssh2_pkt_addbool(unsigned char value); +static void ssh2_pkt_adduint32(unsigned long value); +static void ssh2_pkt_addstring_start(void); +static void ssh2_pkt_addstring_str(char *data); +static void ssh2_pkt_addstring_data(char *data, int len); +static void ssh2_pkt_addstring(char *data); +static char *ssh2_mpint_fmt(Bignum b, int *len); +static void ssh2_pkt_addmp(Bignum b); +static int ssh2_pkt_construct(void); +static void ssh2_pkt_send(void); /* - * Ciphers for SSH2. We miss out single-DES because it isn't - * supported; also 3DES and Blowfish are both done differently from - * SSH1. (3DES uses outer chaining; Blowfish has the opposite - * endianness and different-sized keys.) + * Buffer management constants. There are several of these for + * various different purposes: + * + * - SSH1_BUFFER_LIMIT is the amount of backlog that must build up + * on a local data stream before we throttle the whole SSH + * connection (in SSH1 only). Throttling the whole connection is + * pretty drastic so we set this high in the hope it won't + * happen very often. + * + * - SSH_MAX_BACKLOG is the amount of backlog that must build up + * on the SSH connection itself before we defensively throttle + * _all_ local data streams. This is pretty drastic too (though + * thankfully unlikely in SSH2 since the window mechanism should + * ensure that the server never has any need to throttle its end + * of the connection), so we set this high as well. + * + * - OUR_V2_WINSIZE is the maximum window size we present on SSH2 + * channels. */ -const static struct ssh2_ciphers *ciphers[] = { - &ssh2_aes, - &ssh2_blowfish, - &ssh2_3des, -}; + +#define SSH1_BUFFER_LIMIT 32768 +#define SSH_MAX_BACKLOG 32768 +#define OUR_V2_WINSIZE 16384 const static struct ssh_kex *kex_algs[] = { &ssh_diffiehellman_gex, @@ -263,6 +418,8 @@ enum { /* channel types */ CHAN_MAINSESSION, CHAN_X11, CHAN_AGENT, + CHAN_SOCKDATA, + CHAN_SOCKDATA_DORMANT /* one the remote hasn't confirmed */ }; /* @@ -271,12 +428,27 @@ enum { /* channel types */ struct ssh_channel { unsigned remoteid, localid; int type; + /* + * In SSH1, this value contains four bits: + * + * 1 We have sent SSH1_MSG_CHANNEL_CLOSE. + * 2 We have sent SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION. + * 4 We have received SSH1_MSG_CHANNEL_CLOSE. + * 8 We have received SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION. + * + * A channel is completely finished with when all four bits are set. + */ int closes; - struct ssh2_data_channel { - unsigned char *outbuffer; - unsigned outbuflen, outbufsize; - unsigned remwindow, remmaxpkt; - } v2; + union { + struct ssh1_data_channel { + int throttling; + } v1; + struct ssh2_data_channel { + bufchain outbuffer; + unsigned remwindow, remmaxpkt; + unsigned locwindow; + } v2; + } v; union { struct ssh_agent_channel { unsigned char *message; @@ -286,9 +458,46 @@ struct ssh_channel { struct ssh_x11_channel { Socket s; } x11; + struct ssh_pfd_channel { + Socket s; + } pfd; } u; }; +/* + * 2-3-4 tree storing remote->local port forwardings. SSH 1 and SSH + * 2 use this structure in different ways, reflecting SSH 2's + * altogether saner approach to port forwarding. + * + * In SSH 1, you arrange a remote forwarding by sending the server + * the remote port number, and the local destination host:port. + * When a connection comes in, the server sends you back that + * host:port pair, and you connect to it. This is a ready-made + * security hole if you're not on the ball: a malicious server + * could send you back _any_ host:port pair, so if you trustingly + * connect to the address it gives you then you've just opened the + * entire inside of your corporate network just by connecting + * through it to a dodgy SSH server. Hence, we must store a list of + * host:port pairs we _are_ trying to forward to, and reject a + * connection request from the server if it's not in the list. + * + * In SSH 2, each side of the connection minds its own business and + * doesn't send unnecessary information to the other. You arrange a + * remote forwarding by sending the server just the remote port + * number. When a connection comes in, the server tells you which + * of its ports was connected to; and _you_ have to remember what + * local host:port pair went with that port number. + * + * Hence: in SSH 1 this structure stores host:port pairs we intend + * to allow connections to, and is indexed by those host:port + * pairs. In SSH 2 it stores a mapping from source port to + * destination host:port pair, and is indexed by source port. + */ +struct ssh_rportfwd { + unsigned sport, dport; + char dhost[256]; +}; + struct Packet { long length; int type; @@ -319,16 +528,19 @@ static const struct ssh_compress *sccomp = NULL; static const struct ssh_kex *kex = NULL; static const struct ssh_signkey *hostkey = NULL; static unsigned char ssh2_session_id[20]; -int (*ssh_get_line) (const char *prompt, char *str, int maxlen, - int is_pw) = NULL; static char *savedhost; static int savedport; static int ssh_send_ok; static int ssh_echoing, ssh_editing; +static void *frontend; + static tree234 *ssh_channels; /* indexed by local id */ static struct ssh_channel *mainchan; /* primary session channel */ +static int ssh_exitcode = -1; + +static tree234 *ssh_rportfwds; static enum { SSH_STATE_PREPACKET, @@ -345,17 +557,30 @@ static struct Packet pktout = { 0, 0, NULL, NULL, 0 }; static unsigned char *deferred_send_data = NULL; static int deferred_len = 0, deferred_size = 0; +/* + * Gross hack: pscp will try to start SFTP but fall back to scp1 if + * that fails. This variable is the means by which scp.c can reach + * into the SSH code and find out which one it got. + */ +int ssh_fallback_cmd = 0; + static int ssh_version; +static int ssh1_throttle_count; +static int ssh_overall_bufsize; +static int ssh_throttled_all; +static int ssh1_stdout_throttling; static void (*ssh_protocol) (unsigned char *in, int inlen, int ispkt); static void ssh1_protocol(unsigned char *in, int inlen, int ispkt); static void ssh2_protocol(unsigned char *in, int inlen, int ispkt); static void ssh_size(void); static void ssh_special(Telnet_Special); -static void ssh2_try_send(struct ssh_channel *c); +static int ssh2_try_send(struct ssh_channel *c); static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len); - +static void ssh_throttle_all(int enable, int bufsize); +static void ssh2_set_window(struct ssh_channel *c, unsigned newwin); static int (*s_rdpkt) (unsigned char **data, int *datalen); +static int ssh_sendbuffer(void); static struct rdpkt1_state_tag { long len, pad, biglen, to_read; @@ -393,6 +618,32 @@ static int ssh_channelfind(void *av, void *bv) return 0; } +static int ssh_rportcmp_ssh1(void *av, void *bv) +{ + struct ssh_rportfwd *a = (struct ssh_rportfwd *) av; + struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv; + int i; + if ( (i = strcmp(a->dhost, b->dhost)) != 0) + return i < 0 ? -1 : +1; + if (a->dport > b->dport) + return +1; + if (a->dport < b->dport) + return -1; + return 0; +} + +static int ssh_rportcmp_ssh2(void *av, void *bv) +{ + struct ssh_rportfwd *a = (struct ssh_rportfwd *) av; + struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv; + + if (a->sport > b->sport) + return +1; + if (a->sport < b->sport) + return -1; + return 0; +} + static int alloc_channel_id(void) { const unsigned CHANNEL_NUMBER_OFFSET = 256; @@ -440,7 +691,7 @@ static void c_write(char *buf, int len) fputc(buf[i], stderr); return; } - from_backend(1, buf, len); + from_backend(frontend, 1, buf, len); } static void c_write_untrusted(char *buf, int len) @@ -485,12 +736,6 @@ static int ssh1_rdpkt(unsigned char **data, int *datalen) (*data)++, (*datalen)--; } -#ifdef FWHACK - if (st->len == 0x52656d6f) { /* "Remo"te server has closed ... */ - st->len = 0x300; /* big enough to carry to end */ - } -#endif - st->pad = 8 - (st->len % 8); st->biglen = st->len + st->pad; pktin.length = st->len - 5; @@ -518,12 +763,13 @@ static int ssh1_rdpkt(unsigned char **data, int *datalen) st->to_read -= st->chunk; } + if (cipher && detect_attack(pktin.data, st->biglen, NULL)) { + bombout(("Network attack (CRC compensation) detected!")); + crReturn(0); + } + if (cipher) cipher->decrypt(pktin.data, st->biglen); -#ifdef DUMP_PACKETS - debug(("Got packet len=%d pad=%d\n", st->len, st->pad)); - dmemdump(pktin.data, st->biglen); -#endif st->realcrc = crc32(pktin.data, st->biglen - 4); st->gotcrc = GET_32BIT(pktin.data + st->biglen - 4); @@ -537,10 +783,6 @@ static int ssh1_rdpkt(unsigned char **data, int *datalen) if (ssh1_compressing) { unsigned char *decompblk; int decomplen; -#ifdef DUMP_PACKETS - debug(("Packet payload pre-decompression:\n")); - dmemdump(pktin.body - 1, pktin.length + 1); -#endif zlib_decompress_block(pktin.body - 1, pktin.length + 1, &decompblk, &decomplen); @@ -555,35 +797,34 @@ static int ssh1_rdpkt(unsigned char **data, int *datalen) memcpy(pktin.body - 1, decompblk, decomplen); sfree(decompblk); pktin.length = decomplen - 1; -#ifdef DUMP_PACKETS - debug(("Packet payload post-decompression:\n")); - dmemdump(pktin.body - 1, pktin.length + 1); -#endif } + pktin.type = pktin.body[-1]; + + log_packet(PKT_INCOMING, pktin.type, ssh1_pkt_type(pktin.type), + pktin.body, pktin.length); + if (pktin.type == SSH1_SMSG_STDOUT_DATA || pktin.type == SSH1_SMSG_STDERR_DATA || pktin.type == SSH1_MSG_DEBUG || pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE || pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) { - long strlen = GET_32BIT(pktin.body); - if (strlen + 4 != pktin.length) { + long stringlen = GET_32BIT(pktin.body); + if (stringlen + 4 != pktin.length) { bombout(("Received data packet with bogus string length")); crReturn(0); } } - pktin.type = pktin.body[-1]; - if (pktin.type == SSH1_MSG_DEBUG) { /* log debug message */ - char buf[80]; - int strlen = GET_32BIT(pktin.body); - strcpy(buf, "Remote: "); - if (strlen > 70) - strlen = 70; - memcpy(buf + 8, pktin.body + 4, strlen); - buf[8 + strlen] = '\0'; + char buf[512]; + int stringlen = GET_32BIT(pktin.body); + strcpy(buf, "Remote debug message: "); + if (stringlen > 480) + stringlen = 480; + memcpy(buf + 8, pktin.body + 4, stringlen); + buf[8 + stringlen] = '\0'; logevent(buf); goto next_packet; } else if (pktin.type == SSH1_MSG_IGNORE) { @@ -602,7 +843,9 @@ static int ssh1_rdpkt(unsigned char **data, int *datalen) msglen = sizeof(buf) - nowlen - 1; memcpy(buf + nowlen, pktin.body + 4, msglen); buf[nowlen + msglen] = '\0'; - logevent(buf); + /* logevent(buf); (this is now done within the bombout macro) */ + bombout(("Server sent disconnect message:\n\"%s\"", buf+nowlen)); + crReturn(0); } crFinish(0); @@ -646,11 +889,7 @@ static int ssh2_rdpkt(unsigned char **data, int *datalen) pktin.data[st->i] = *(*data)++; (*datalen)--; } -#ifdef FWHACK - if (!memcmp(pktin.data, "Remo", 4)) { /* "Remo"te server has closed ... */ - /* FIXME */ - } -#endif + if (sccipher) sccipher->decrypt(pktin.data, st->cipherblk); @@ -661,6 +900,15 @@ static int ssh2_rdpkt(unsigned char **data, int *datalen) st->pad = pktin.data[4]; /* + * _Completely_ silly lengths should be stomped on before they + * do us any more damage. + */ + if (st->len < 0 || st->pad < 0 || st->len + st->pad < 0) { + bombout(("Incoming packet was garbled on decryption")); + crReturn(0); + } + + /* * This enables us to deduce the payload length. */ st->payload = st->len - st->pad - 1; @@ -703,11 +951,6 @@ static int ssh2_rdpkt(unsigned char **data, int *datalen) sccipher->decrypt(pktin.data + st->cipherblk, st->packetlen - st->cipherblk); -#ifdef DUMP_PACKETS - debug(("Got packet len=%d pad=%d\n", st->len, st->pad)); - dmemdump(pktin.data, st->packetlen); -#endif - /* * Check the MAC. */ @@ -740,11 +983,6 @@ static int ssh2_rdpkt(unsigned char **data, int *datalen) } pktin.length = 5 + newlen; memcpy(pktin.data + 5, newpayload, newlen); -#ifdef DUMP_PACKETS - debug(("Post-decompression payload:\n")); - dmemdump(pktin.data + 5, newlen); -#endif - sfree(newpayload); } } @@ -752,30 +990,108 @@ static int ssh2_rdpkt(unsigned char **data, int *datalen) pktin.savedpos = 6; pktin.type = pktin.data[5]; - if (pktin.type == SSH2_MSG_IGNORE || pktin.type == SSH2_MSG_DEBUG) - goto next_packet; /* FIXME: print DEBUG message */ - - if (pktin.type == SSH2_MSG_DISCONNECT) { - /* log reason code in disconnect message */ - char buf[256]; - int reason = GET_32BIT(pktin.data + 6); - unsigned msglen = GET_32BIT(pktin.data + 10); - unsigned nowlen; - if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) { - sprintf(buf, "Received disconnect message (%s)", - ssh2_disconnect_reasons[reason]); - } else { - sprintf(buf, "Received disconnect message (unknown type %d)", - reason); + log_packet(PKT_INCOMING, pktin.type, ssh2_pkt_type(pktin.type), + pktin.data+6, pktin.length-6); + + switch (pktin.type) { + /* + * These packets we must handle instantly. + */ + case SSH2_MSG_DISCONNECT: + { + /* log reason code in disconnect message */ + char buf[256]; + int reason = GET_32BIT(pktin.data + 6); + unsigned msglen = GET_32BIT(pktin.data + 10); + unsigned nowlen; + if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) { + sprintf(buf, "Received disconnect message (%s)", + ssh2_disconnect_reasons[reason]); + } else { + sprintf(buf, "Received disconnect message (unknown type %d)", + reason); + } + logevent(buf); + strcpy(buf, "Disconnection message text: "); + nowlen = strlen(buf); + if (msglen > sizeof(buf) - nowlen - 1) + msglen = sizeof(buf) - nowlen - 1; + memcpy(buf + nowlen, pktin.data + 14, msglen); + buf[nowlen + msglen] = '\0'; + logevent(buf); + bombout(("Server sent disconnect message\ntype %d (%s):\n\"%s\"", + reason, + (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ? + ssh2_disconnect_reasons[reason] : "unknown", + buf+nowlen)); + crReturn(0); + } + break; + case SSH2_MSG_IGNORE: + goto next_packet; + case SSH2_MSG_DEBUG: + { + /* log the debug message */ + char buf[512]; + /* int display = pktin.body[6]; */ + int stringlen = GET_32BIT(pktin.data+7); + int prefix; + strcpy(buf, "Remote debug message: "); + prefix = strlen(buf); + if (stringlen > sizeof(buf)-prefix-1) + stringlen = sizeof(buf)-prefix-1; + memcpy(buf + prefix, pktin.data + 11, stringlen); + buf[prefix + stringlen] = '\0'; + logevent(buf); } - logevent(buf); - strcpy(buf, "Disconnection message text: "); - nowlen = strlen(buf); - if (msglen > sizeof(buf) - nowlen - 1) - msglen = sizeof(buf) - nowlen - 1; - memcpy(buf + nowlen, pktin.data + 14, msglen); - buf[nowlen + msglen] = '\0'; - logevent(buf); + goto next_packet; /* FIXME: print the debug message */ + + /* + * These packets we need do nothing about here. + */ + case SSH2_MSG_UNIMPLEMENTED: + case SSH2_MSG_SERVICE_REQUEST: + case SSH2_MSG_SERVICE_ACCEPT: + case SSH2_MSG_KEXINIT: + case SSH2_MSG_NEWKEYS: + case SSH2_MSG_KEXDH_INIT: + case SSH2_MSG_KEXDH_REPLY: + /* case SSH2_MSG_KEX_DH_GEX_REQUEST: duplicate case value */ + /* case SSH2_MSG_KEX_DH_GEX_GROUP: duplicate case value */ + case SSH2_MSG_KEX_DH_GEX_INIT: + case SSH2_MSG_KEX_DH_GEX_REPLY: + case SSH2_MSG_USERAUTH_REQUEST: + case SSH2_MSG_USERAUTH_FAILURE: + case SSH2_MSG_USERAUTH_SUCCESS: + case SSH2_MSG_USERAUTH_BANNER: + case SSH2_MSG_USERAUTH_PK_OK: + /* case SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ: duplicate case value */ + /* case SSH2_MSG_USERAUTH_INFO_REQUEST: duplicate case value */ + case SSH2_MSG_USERAUTH_INFO_RESPONSE: + case SSH2_MSG_GLOBAL_REQUEST: + case SSH2_MSG_REQUEST_SUCCESS: + case SSH2_MSG_REQUEST_FAILURE: + case SSH2_MSG_CHANNEL_OPEN: + case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: + case SSH2_MSG_CHANNEL_OPEN_FAILURE: + case SSH2_MSG_CHANNEL_WINDOW_ADJUST: + case SSH2_MSG_CHANNEL_DATA: + case SSH2_MSG_CHANNEL_EXTENDED_DATA: + case SSH2_MSG_CHANNEL_EOF: + case SSH2_MSG_CHANNEL_CLOSE: + case SSH2_MSG_CHANNEL_REQUEST: + case SSH2_MSG_CHANNEL_SUCCESS: + case SSH2_MSG_CHANNEL_FAILURE: + break; + + /* + * For anything else we send SSH2_MSG_UNIMPLEMENTED. + */ + default: + ssh2_pkt_init(SSH2_MSG_UNIMPLEMENTED); + ssh2_pkt_adduint32(st->incoming_sequence - 1); + ssh2_pkt_send(); + break; } crFinish(0); @@ -820,10 +1136,8 @@ static int s_wrpkt_prepare(void) pktout.body[-1] = pktout.type; -#ifdef DUMP_PACKETS - debug(("Packet payload pre-compression:\n")); - dmemdump(pktout.body - 1, pktout.length + 1); -#endif + log_packet(PKT_OUTGOING, pktout.type, ssh1_pkt_type(pktout.type), + pktout.body, pktout.length); if (ssh1_compressing) { unsigned char *compblk; @@ -833,10 +1147,6 @@ static int s_wrpkt_prepare(void) ssh1_pktout_size(complen - 1); memcpy(pktout.body - 1, compblk, complen); sfree(compblk); -#ifdef DUMP_PACKETS - debug(("Packet payload post-compression:\n")); - dmemdump(pktout.body - 1, pktout.length + 1); -#endif } len = pktout.length + 5; /* type and CRC */ @@ -849,10 +1159,6 @@ static int s_wrpkt_prepare(void) PUT_32BIT(pktout.data + biglen, crc); PUT_32BIT(pktout.data, len); -#ifdef DUMP_PACKETS - debug(("Sending packet len=%d\n", biglen + 4)); - dmemdump(pktout.data, biglen + 4); -#endif if (cipher) cipher->encrypt(pktout.data + 4, biglen); @@ -861,9 +1167,11 @@ static int s_wrpkt_prepare(void) static void s_wrpkt(void) { - int len; + int len, backlog; len = s_wrpkt_prepare(); - sk_write(s, pktout.data, len); + backlog = sk_write(s, pktout.data, len); + if (backlog > SSH_MAX_BACKLOG) + ssh_throttle_all(1, backlog); } static void s_wrpkt_defer(void) @@ -1114,13 +1422,12 @@ static int ssh2_pkt_construct(void) int cipherblk, maclen, padding, i; static unsigned long outgoing_sequence = 0; + log_packet(PKT_OUTGOING, pktout.data[5], ssh2_pkt_type(pktout.data[5]), + pktout.data + 6, pktout.length - 6); + /* * Compress packet payload. */ -#ifdef DUMP_PACKETS - debug(("Pre-compression payload:\n")); - dmemdump(pktout.data + 5, pktout.length - 5); -#endif { unsigned char *newpayload; int newlen; @@ -1152,11 +1459,6 @@ static int ssh2_pkt_construct(void) outgoing_sequence); outgoing_sequence++; /* whether or not we MACed */ -#ifdef DUMP_PACKETS - debug(("Sending packet len=%d\n", pktout.length + padding)); - dmemdump(pktout.data, pktout.length + padding); -#endif - if (cscipher) cscipher->encrypt(pktout.data, pktout.length + padding); @@ -1169,8 +1471,12 @@ static int ssh2_pkt_construct(void) */ static void ssh2_pkt_send(void) { - int len = ssh2_pkt_construct(); - sk_write(s, pktout.data, len); + int len; + int backlog; + len = ssh2_pkt_construct(); + backlog = sk_write(s, pktout.data, len); + if (backlog > SSH_MAX_BACKLOG) + ssh_throttle_all(1, backlog); } /* @@ -1201,10 +1507,13 @@ static void ssh2_pkt_defer(void) */ static void ssh_pkt_defersend(void) { - sk_write(s, deferred_send_data, deferred_len); + int backlog; + backlog = sk_write(s, deferred_send_data, deferred_len); deferred_len = deferred_size = 0; sfree(deferred_send_data); deferred_send_data = NULL; + if (backlog > SSH_MAX_BACKLOG) + ssh_throttle_all(1, backlog); } #if 0 @@ -1254,6 +1563,7 @@ static int ssh2_pkt_getbool(void) static void ssh2_pkt_getstring(char **p, int *length) { *p = NULL; + *length = 0; if (pktin.length - pktin.savedpos < 4) return; *length = GET_32BIT(pktin.data + pktin.savedpos); @@ -1281,6 +1591,75 @@ static Bignum ssh2_pkt_getmp(void) } /* + * Helper function to add an SSH2 signature blob to a packet. + * Expects to be shown the public key blob as well as the signature + * blob. Normally works just like ssh2_pkt_addstring, but will + * fiddle with the signature packet if necessary for + * BUG_SSH2_RSA_PADDING. + */ +static void ssh2_add_sigblob(void *pkblob_v, int pkblob_len, + void *sigblob_v, int sigblob_len) +{ + unsigned char *pkblob = (unsigned char *)pkblob_v; + unsigned char *sigblob = (unsigned char *)sigblob_v; + + /* dmemdump(pkblob, pkblob_len); */ + /* dmemdump(sigblob, sigblob_len); */ + + /* + * See if this is in fact an ssh-rsa signature and a buggy + * server; otherwise we can just do this the easy way. + */ + if ((ssh_remote_bugs & BUG_SSH2_RSA_PADDING) && + (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) { + int pos, len, siglen; + + /* + * Find the byte length of the modulus. + */ + + pos = 4+7; /* skip over "ssh-rsa" */ + pos += 4 + GET_32BIT(pkblob+pos); /* skip over exponent */ + len = GET_32BIT(pkblob+pos); /* find length of modulus */ + pos += 4; /* find modulus itself */ + while (len > 0 && pkblob[pos] == 0) + len--, pos++; + /* debug(("modulus length is %d\n", len)); */ + + /* + * Now find the signature integer. + */ + pos = 4+7; /* skip over "ssh-rsa" */ + siglen = GET_32BIT(sigblob+pos); + /* debug(("signature length is %d\n", siglen)); */ + + if (len != siglen) { + unsigned char newlen[4]; + ssh2_pkt_addstring_start(); + ssh2_pkt_addstring_data(sigblob, pos); + /* dmemdump(sigblob, pos); */ + pos += 4; /* point to start of actual sig */ + PUT_32BIT(newlen, len); + ssh2_pkt_addstring_data(newlen, 4); + /* dmemdump(newlen, 4); */ + newlen[0] = 0; + while (len-- > siglen) { + ssh2_pkt_addstring_data(newlen, 1); + /* dmemdump(newlen, 1); */ + } + ssh2_pkt_addstring_data(sigblob+pos, siglen); + /* dmemdump(sigblob+pos, siglen); */ + return; + } + + /* Otherwise fall through and do it the easy way. */ + } + + ssh2_pkt_addstring_start(); + ssh2_pkt_addstring_data(sigblob, sigblob_len); +} + +/* * Examine the remote side's version string and compare it against * a list of known buggy implementations. */ @@ -1289,17 +1668,17 @@ static void ssh_detect_bugs(char *vstring) char *imp; /* pointer to implementation part */ imp = vstring; imp += strcspn(imp, "-"); - if (*imp) - imp++; + if (*imp) imp++; imp += strcspn(imp, "-"); - if (*imp) - imp++; + if (*imp) imp++; ssh_remote_bugs = 0; - if (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") || - !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") || - !strcmp(imp, "1.2.22")) { + if (cfg.sshbug_ignore1 == BUG_ON || + (cfg.sshbug_ignore1 == BUG_AUTO && + (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") || + !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") || + !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25")))) { /* * These versions don't support SSH1_MSG_IGNORE, so we have * to use a different defence against password length @@ -1309,25 +1688,83 @@ static void ssh_detect_bugs(char *vstring) logevent("We believe remote version has SSH1 ignore bug"); } - if (!strncmp(imp, "2.1.0", 5) || !strncmp(imp, "2.0.", 4) || - !strncmp(imp, "2.2.0", 5) || !strncmp(imp, "2.3.0", 5) || - !strncmp(imp, "2.1 ", 4)) { + if (cfg.sshbug_plainpw1 == BUG_ON || + (cfg.sshbug_plainpw1 == BUG_AUTO && + (!strcmp(imp, "Cisco-1.25")))) { + /* + * These versions need a plain password sent; they can't + * handle having a null and a random length of data after + * the password. + */ + ssh_remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD; + logevent("We believe remote version needs a plain SSH1 password"); + } + + if (cfg.sshbug_rsa1 == BUG_ON || + (cfg.sshbug_rsa1 == BUG_AUTO && + (!strcmp(imp, "Cisco-1.25")))) { + /* + * These versions apparently have no clue whatever about + * RSA authentication and will panic and die if they see + * an AUTH_RSA message. + */ + ssh_remote_bugs |= BUG_CHOKES_ON_RSA; + logevent("We believe remote version can't handle RSA authentication"); + } + + if (cfg.sshbug_hmac2 == BUG_ON || + (cfg.sshbug_hmac2 == BUG_AUTO && + (!strncmp(imp, "2.1.0", 5) || !strncmp(imp, "2.0.", 4) || + !strncmp(imp, "2.2.0", 5) || !strncmp(imp, "2.3.0", 5) || + !strncmp(imp, "2.1 ", 4)))) { /* * These versions have the HMAC bug. */ ssh_remote_bugs |= BUG_SSH2_HMAC; logevent("We believe remote version has SSH2 HMAC bug"); } + + if (cfg.sshbug_derivekey2 == BUG_ON || + (cfg.sshbug_derivekey2 == BUG_AUTO && + (!strncmp(imp, "2.0.", 4)))) { + /* + * These versions have the key-derivation bug (failing to + * include the literal shared secret in the hashes that + * generate the keys). + */ + ssh_remote_bugs |= BUG_SSH2_DERIVEKEY; + logevent("We believe remote version has SSH2 key-derivation bug"); + } + + if (cfg.sshbug_rsapad2 == BUG_ON || + (cfg.sshbug_rsapad2 == BUG_AUTO && + ((!strncmp(imp, "OpenSSH_2.", 10) && imp[10]>='5' && imp[10]<='9') || + (!strncmp(imp, "OpenSSH_3.", 10) && imp[10]>='0' && imp[10]<='2')))){ + /* + * These versions have the SSH2 RSA padding bug. + */ + ssh_remote_bugs |= BUG_SSH2_RSA_PADDING; + logevent("We believe remote version has SSH2 RSA padding bug"); + } + + if (cfg.sshbug_dhgex2 == BUG_ON) { + /* + * These versions have the SSH2 DH GEX bug. + */ + ssh_remote_bugs |= BUG_SSH2_DH_GEX; + logevent("We believe remote version has SSH2 DH group exchange bug"); + } } static int do_ssh_init(unsigned char c) { - static char vslen; + static int vslen; static char version[10]; static char *vstring; static int vstrsize; static char *vlog; static int i; + static int proto1, proto2; crBegin; @@ -1350,8 +1787,8 @@ static int do_ssh_init(unsigned char c) crReturn(1); /* get another character */ } - vstring = smalloc(16); vstrsize = 16; + vstring = smalloc(vstrsize); strcpy(vstring, "SSH-"); vslen = 4; i = 0; @@ -1377,19 +1814,33 @@ static int do_ssh_init(unsigned char c) vstring[vslen] = 0; vlog = smalloc(20 + vslen); + vstring[strcspn (vstring, "\r\n")] = '\0'; /* remove end-of-line chars */ sprintf(vlog, "Server version: %s", vstring); - ssh_detect_bugs(vstring); - vlog[strcspn(vlog, "\r\n")] = '\0'; logevent(vlog); + ssh_detect_bugs(vstring); sfree(vlog); /* - * Server version "1.99" means we can choose whether we use v1 - * or v2 protocol. Choice is based on cfg.sshprot. + * Decide which SSH protocol version to support. */ - if (ssh_versioncmp(version, cfg.sshprot == 1 ? "2.0" : "1.99") >= 0) { + + /* Anything strictly below "2.0" means protocol 1 is supported. */ + proto1 = ssh_versioncmp(version, "2.0") < 0; + /* Anything greater or equal to "1.99" means protocol 2 is supported. */ + proto2 = ssh_versioncmp(version, "1.99") >= 0; + + if (cfg.sshprot == 0 && !proto1) { + bombout(("SSH protocol version 1 required by user but not provided by server")); + crReturn(0); + } + if (cfg.sshprot == 3 && !proto2) { + bombout(("SSH protocol version 2 required by user but not provided by server")); + crReturn(0); + } + + if (proto2 && (cfg.sshprot >= 2 || !proto1)) { /* - * This is a v2 server. Begin v2 protocol. + * Use v2 protocol. */ char verstring[80], vlog[100]; sprintf(verstring, "SSH-2.0-%s", sshver); @@ -1409,7 +1860,7 @@ static int do_ssh_init(unsigned char c) s_rdpkt = ssh2_rdpkt; } else { /* - * This is a v1 server. Begin v1 protocol. + * Use v1 protocol. */ char verstring[80], vlog[100]; sprintf(verstring, "SSH-%s-%s", @@ -1418,6 +1869,7 @@ static int do_ssh_init(unsigned char c) sprintf(vlog, "We claim version: %s", verstring); logevent(vlog); strcat(verstring, "\n"); + logevent("Using SSH protocol version 1"); sk_write(s, verstring, strlen(verstring)); ssh_protocol = ssh1_protocol; @@ -1463,6 +1915,9 @@ static void ssh_gotdata(unsigned char *data, int datalen) while (1) { while (datalen > 0) { if (s_rdpkt(&data, &datalen) == 0) { + if (ssh_state == SSH_STATE_CLOSED) { + return; + } ssh_protocol(NULL, 0, 1); if (ssh_state == SSH_STATE_CLOSED) { return; @@ -1478,10 +1933,13 @@ static int ssh_closing(Plug plug, char *error_msg, int error_code, int calling_back) { ssh_state = SSH_STATE_CLOSED; - sk_close(s); - s = NULL; + if (s) { + sk_close(s); + s = NULL; + } if (error_msg) { /* A socket error has occurred. */ + logevent(error_msg); connection_fatal(error_msg); } else { /* Otherwise, the remote side closed the connection normally. */ @@ -1502,17 +1960,29 @@ static int ssh_receive(Plug plug, int urgent, char *data, int len) return 1; } +static void ssh_sent(Plug plug, int bufsize) +{ + /* + * If the send backlog on the SSH socket itself clears, we + * should unthrottle the whole world if it was throttled. + */ + if (bufsize < SSH_MAX_BACKLOG) + ssh_throttle_all(0, bufsize); +} + /* * Connect to specified host and port. * Returns an error message, or NULL on success. * Also places the canonical host name into `realhost'. It must be * freed by the caller. */ -static char *connect_to_host(char *host, int port, char **realhost) +static char *connect_to_host(char *host, int port, char **realhost, int nodelay) { static struct plug_function_table fn_table = { ssh_closing, - ssh_receive + ssh_receive, + ssh_sent, + NULL }, *fn_table_ptr = &fn_table; SockAddr addr; @@ -1541,6 +2011,11 @@ static char *connect_to_host(char *host, int port, char **realhost) /* * Try to find host. */ + { + char buf[200]; + sprintf(buf, "Looking up host \"%.170s\"", host); + logevent(buf); + } addr = sk_namelookup(host, realhost); if ((err = sk_addr_error(addr))) return err; @@ -1552,9 +2027,17 @@ static char *connect_to_host(char *host, int port, char **realhost) /* * Open socket. */ - s = sk_new(addr, port, 0, 1, &fn_table_ptr); - if ((err = sk_socket_error(s))) + { + char buf[200], addrbuf[100]; + sk_getaddr(addr, addrbuf, 100); + sprintf(buf, "Connecting to %.100s port %d", addrbuf, port); + logevent(buf); + } + s = new_connection(addr, *realhost, port, 0, 1, nodelay, &fn_table_ptr); + if ((err = sk_socket_error(s))) { + s = NULL; return err; + } #ifdef FWHACK sk_write(s, "connect ", 8); @@ -1570,20 +2053,144 @@ static char *connect_to_host(char *host, int port, char **realhost) } /* + * Throttle or unthrottle the SSH connection. + */ +static void ssh1_throttle(int adjust) +{ + int old_count = ssh1_throttle_count; + ssh1_throttle_count += adjust; + assert(ssh1_throttle_count >= 0); + if (ssh1_throttle_count && !old_count) { + sk_set_frozen(s, 1); + } else if (!ssh1_throttle_count && old_count) { + sk_set_frozen(s, 0); + } +} + +/* + * Throttle or unthrottle _all_ local data streams (for when sends + * on the SSH connection itself back up). + */ +static void ssh_throttle_all(int enable, int bufsize) +{ + int i; + struct ssh_channel *c; + + if (enable == ssh_throttled_all) + return; + ssh_throttled_all = enable; + ssh_overall_bufsize = bufsize; + if (!ssh_channels) + return; + for (i = 0; NULL != (c = index234(ssh_channels, i)); i++) { + switch (c->type) { + case CHAN_MAINSESSION: + /* + * This is treated separately, outside the switch. + */ + break; + case CHAN_X11: + x11_override_throttle(c->u.x11.s, enable); + break; + case CHAN_AGENT: + /* Agent channels require no buffer management. */ + break; + case CHAN_SOCKDATA: + pfd_override_throttle(c->u.x11.s, enable); + break; + } + } +} + +/* + * Username and password input, abstracted off into reusable + * routines (hopefully even reusable between SSH1 and SSH2!). + */ +static char *ssh_userpass_input_buffer; +static int ssh_userpass_input_buflen; +static int ssh_userpass_input_bufpos; +static int ssh_userpass_input_echo; + +/* Set up a username or password input loop on a given buffer. */ +void setup_userpass_input(char *buffer, int buflen, int echo) +{ + ssh_userpass_input_buffer = buffer; + ssh_userpass_input_buflen = buflen; + ssh_userpass_input_bufpos = 0; + ssh_userpass_input_echo = echo; +} + +/* + * Process some terminal data in the course of username/password + * input. Returns >0 for success (line of input returned in + * buffer), <0 for failure (user hit ^C/^D, bomb out and exit), 0 + * for inconclusive (keep waiting for more input please). + */ +int process_userpass_input(unsigned char *in, int inlen) +{ + char c; + + while (inlen--) { + switch (c = *in++) { + case 10: + case 13: + ssh_userpass_input_buffer[ssh_userpass_input_bufpos] = 0; + ssh_userpass_input_buffer[ssh_userpass_input_buflen-1] = 0; + return +1; + break; + case 8: + case 127: + if (ssh_userpass_input_bufpos > 0) { + if (ssh_userpass_input_echo) + c_write_str("\b \b"); + ssh_userpass_input_bufpos--; + } + break; + case 21: + case 27: + while (ssh_userpass_input_bufpos > 0) { + if (ssh_userpass_input_echo) + c_write_str("\b \b"); + ssh_userpass_input_bufpos--; + } + break; + case 3: + case 4: + return -1; + break; + default: + if (((c >= ' ' && c <= '~') || + ((unsigned char) c >= 160)) + && ssh_userpass_input_bufpos < ssh_userpass_input_buflen-1) { + ssh_userpass_input_buffer[ssh_userpass_input_bufpos++] = c; + if (ssh_userpass_input_echo) + c_write(&c, 1); + } + break; + } + } + return 0; +} + +/* * Handle the key exchange and user authentication phases. */ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) { - int i, j, len; - unsigned char *rsabuf, *keystr1, *keystr2; + int i, j; + static int len; + static unsigned char *rsabuf, *keystr1, *keystr2; unsigned char cookie[8]; struct RSAKey servkey, hostkey; struct MD5Context md5c; static unsigned long supported_ciphers_mask, supported_auths_mask; - static int tried_publickey; + static int tried_publickey, tried_agent; + static int tis_auth_refused, ccard_auth_refused; static unsigned char session_id[16]; - int cipher_type; + static int cipher_type; static char username[100]; + static void *publickey_blob; + int publickey_bloblen; crBegin; @@ -1673,31 +2280,45 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) logevent("Encrypted session key"); - switch (cfg.cipher) { - case CIPHER_BLOWFISH: - cipher_type = SSH_CIPHER_BLOWFISH; - break; - case CIPHER_DES: - cipher_type = SSH_CIPHER_DES; - break; - case CIPHER_3DES: - cipher_type = SSH_CIPHER_3DES; - break; - case CIPHER_AES: - c_write_str("AES not supported in SSH1, falling back to 3DES\r\n"); - cipher_type = SSH_CIPHER_3DES; - break; - } - if ((supported_ciphers_mask & (1 << cipher_type)) == 0) { - c_write_str - ("Selected cipher not supported, falling back to 3DES\r\n"); - cipher_type = SSH_CIPHER_3DES; - if ((supported_ciphers_mask & (1 << cipher_type)) == 0) { - bombout(("Server violates SSH 1 protocol by " - "not supporting 3DES encryption")); + { + int cipher_chosen = 0, warn = 0; + char *cipher_string = NULL; + for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) { + int next_cipher = cfg.ssh_cipherlist[i]; + if (next_cipher == CIPHER_WARN) { + /* If/when we choose a cipher, warn about it */ + warn = 1; + } else if (next_cipher == CIPHER_AES) { + /* XXX Probably don't need to mention this. */ + logevent("AES not supported in SSH1, skipping"); + } else { + switch (next_cipher) { + case CIPHER_3DES: cipher_type = SSH_CIPHER_3DES; + cipher_string = "3DES"; break; + case CIPHER_BLOWFISH: cipher_type = SSH_CIPHER_BLOWFISH; + cipher_string = "Blowfish"; break; + case CIPHER_DES: cipher_type = SSH_CIPHER_DES; + cipher_string = "single-DES"; break; + } + if (supported_ciphers_mask & (1 << cipher_type)) + cipher_chosen = 1; + } + } + if (!cipher_chosen) { + if ((supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0) + bombout(("Server violates SSH 1 protocol by not " + "supporting 3DES encryption")); + else + /* shouldn't happen */ + bombout(("No supported ciphers found")); crReturn(0); } + + /* Warn about chosen cipher if necessary. */ + if (warn) + askcipher(cipher_string, 0); } + switch (cipher_type) { case SSH_CIPHER_3DES: logevent("Using 3DES encryption"); @@ -1736,10 +2357,8 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) fflush(stdout); { - static int pos = 0; - static char c; if ((flags & FLAG_INTERACTIVE) && !*cfg.username) { - if (ssh_get_line) { + if (ssh_get_line && !ssh_getline_pw_only) { if (!ssh_get_line("login as: ", username, sizeof(username), FALSE)) { /* @@ -1751,52 +2370,22 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) crReturn(1); } } else { + static int ret; c_write_str("login as: "); ssh_send_ok = 1; - while (pos >= 0) { + + setup_userpass_input(username, sizeof(username), 1); + do { crWaitUntil(!ispkt); - while (inlen--) - switch (c = *in++) { - case 10: - case 13: - username[pos] = 0; - pos = -1; - break; - case 8: - case 127: - if (pos > 0) { - c_write_str("\b \b"); - pos--; - } - break; - case 21: - case 27: - while (pos > 0) { - c_write_str("\b \b"); - pos--; - } - break; - case 3: - case 4: - random_save_seed(); - exit(0); - break; - default: - if (((c >= ' ' && c <= '~') || - ((unsigned char) c >= 160)) - && pos < sizeof(username)-1) { - username[pos++] = c; - c_write(&c, 1); - } - break; - } - } + ret = process_userpass_input(in, inlen); + } while (ret == 0); + if (ret < 0) + cleanup_exit(0); c_write_str("\r\n"); - username[strcspn(username, "\n\r")] = '\0'; } } else { - strncpy(username, cfg.username, 99); - username[99] = '\0'; + strncpy(username, cfg.username, sizeof(username)); + username[sizeof(username)-1] = '\0'; } send_packet(SSH1_CMSG_USER, PKT_STR, username, PKT_END); @@ -1814,7 +2403,19 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) crWaitUntil(ispkt); - tried_publickey = 0; + if ((ssh_remote_bugs & BUG_CHOKES_ON_RSA)) { + /* We must not attempt PK auth. Pretend we've already tried it. */ + tried_publickey = tried_agent = 1; + } else { + tried_publickey = tried_agent = 0; + } + tis_auth_refused = ccard_auth_refused = 0; + /* Load the public half of cfg.keyfile so we notice if it's in Pageant */ + if (*cfg.keyfile) { + if (!rsakey_pubblob(cfg.keyfile, &publickey_blob, &publickey_bloblen)) + publickey_blob = NULL; + } else + publickey_blob = NULL; while (pktin.type == SSH1_SMSG_FAILURE) { static char password[100]; @@ -1822,13 +2423,9 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) static int pos; static char c; static int pwpkt_type; - /* - * Show password prompt, having first obtained it via a TIS - * or CryptoCard exchange if we're doing TIS or CryptoCard - * authentication. - */ pwpkt_type = SSH1_CMSG_AUTH_PASSWORD; - if (agent_exists()) { + + if (agent_exists() && !tried_agent) { /* * Attempt RSA authentication using Pageant. */ @@ -1838,6 +2435,7 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) static int authed = FALSE; void *r; + tried_agent = 1; logevent("Pageant is running. Requesting keys."); /* Request the keys held by the agent. */ @@ -1866,6 +2464,11 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) sprintf(buf, "Trying Pageant key #%d", i); logevent(buf); } + if (publickey_blob && + !memcmp(p, publickey_blob, publickey_bloblen)) { + logevent("This key matches configured key file"); + tried_publickey = 1; + } p += 4; p += ssh1_read_bignum(p, &key.exponent); p += ssh1_read_bignum(p, &key.modulus); @@ -1884,6 +2487,7 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) ssh1_read_bignum(pktin.body, &challenge); { char *agentreq, *q, *ret; + void *vret; int len, retlen; len = 1 + 4; /* message type, bit count */ len += ssh1_bignum_length(key.exponent); @@ -1903,7 +2507,8 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) memcpy(q, session_id, 16); q += 16; PUT_32BIT(q, 1); /* response format */ - agent_query(agentreq, len + 4, &ret, &retlen); + agent_query(agentreq, len + 4, &vret, &retlen); + ret = vret; sfree(agentreq); if (ret) { if (ret[4] == SSH1_AGENT_RSA_RESPONSE) { @@ -1948,9 +2553,9 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) if (*cfg.keyfile && !tried_publickey) pwpkt_type = SSH1_CMSG_AUTH_RSA; - if (pktin.type == SSH1_SMSG_FAILURE && - cfg.try_tis_auth && - (supported_auths_mask & (1 << SSH1_AUTH_TIS))) { + if (cfg.try_tis_auth && + (supported_auths_mask & (1 << SSH1_AUTH_TIS)) && + !tis_auth_refused) { pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE; logevent("Requested TIS authentication"); send_packet(SSH1_CMSG_AUTH_TIS, PKT_END); @@ -1959,6 +2564,8 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) logevent("TIS authentication declined"); if (flags & FLAG_INTERACTIVE) c_write_str("TIS authentication refused.\r\n"); + tis_auth_refused = 1; + continue; } else { int challengelen = ((pktin.body[0] << 24) | (pktin.body[1] << 16) | @@ -1968,12 +2575,17 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) if (challengelen > sizeof(prompt) - 1) challengelen = sizeof(prompt) - 1; /* prevent overrun */ memcpy(prompt, pktin.body + 4, challengelen); - prompt[challengelen] = '\0'; + /* Prompt heuristic comes from OpenSSH */ + strncpy(prompt + challengelen, + memchr(prompt, '\n', challengelen) ? + "": "\r\nResponse: ", + (sizeof prompt) - challengelen); + prompt[(sizeof prompt) - 1] = '\0'; } } - if (pktin.type == SSH1_SMSG_FAILURE && - cfg.try_tis_auth && - (supported_auths_mask & (1 << SSH1_AUTH_CCARD))) { + if (cfg.try_tis_auth && + (supported_auths_mask & (1 << SSH1_AUTH_CCARD)) && + !ccard_auth_refused) { pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE; logevent("Requested CryptoCard authentication"); send_packet(SSH1_CMSG_AUTH_CCARD, PKT_END); @@ -1981,6 +2593,8 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) if (pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) { logevent("CryptoCard authentication declined"); c_write_str("CryptoCard authentication refused.\r\n"); + ccard_auth_refused = 1; + continue; } else { int challengelen = ((pktin.body[0] << 24) | (pktin.body[1] << 16) | @@ -1990,7 +2604,9 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) if (challengelen > sizeof(prompt) - 1) challengelen = sizeof(prompt) - 1; /* prevent overrun */ memcpy(prompt, pktin.body + 4, challengelen); - strncpy(prompt + challengelen, "\r\nResponse : ", + strncpy(prompt + challengelen, + memchr(prompt, '\n', challengelen) ? + "" : "\r\nResponse: ", sizeof(prompt) - challengelen); prompt[sizeof(prompt) - 1] = '\0'; } @@ -2001,8 +2617,22 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) } if (pwpkt_type == SSH1_CMSG_AUTH_RSA) { char *comment = NULL; + int type; + char msgbuf[256]; if (flags & FLAG_VERBOSE) c_write_str("Trying public key authentication.\r\n"); + sprintf(msgbuf, "Trying public key \"%.200s\"", cfg.keyfile); + logevent(msgbuf); + type = key_type(cfg.keyfile); + if (type != SSH_KEYTYPE_SSH1) { + sprintf(msgbuf, "Key is of wrong type (%s)", + key_type_to_str(type)); + logevent(msgbuf); + c_write_str(msgbuf); + c_write_str("\r\n"); + tried_publickey = 1; + continue; + } if (!rsakey_encrypted(cfg.keyfile, &comment)) { if (flags & FLAG_VERBOSE) c_write_str("No passphrase required.\r\n"); @@ -2012,6 +2642,11 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) sfree(comment); } + /* + * Show password prompt, having first obtained it via a TIS + * or CryptoCard exchange if we're doing TIS or CryptoCard + * authentication. + */ if (ssh_get_line) { if (!ssh_get_line(prompt, password, sizeof(password), TRUE)) { /* @@ -2022,43 +2657,25 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) send_packet(SSH1_MSG_DISCONNECT, PKT_STR, "No more passwords available to try", PKT_END); + logevent("Unable to authenticate"); connection_fatal("Unable to authenticate"); ssh_state = SSH_STATE_CLOSED; crReturn(1); } } else { - c_write_str(prompt); + /* Prompt may have come from server. We've munged it a bit, so + * we know it to be zero-terminated at least once. */ + static int ret; + c_write_untrusted(prompt, strlen(prompt)); pos = 0; - ssh_send_ok = 1; - while (pos >= 0) { + + setup_userpass_input(password, sizeof(password), 0); + do { crWaitUntil(!ispkt); - while (inlen--) - switch (c = *in++) { - case 10: - case 13: - password[pos] = 0; - pos = -1; - break; - case 8: - case 127: - if (pos > 0) - pos--; - break; - case 21: - case 27: - pos = 0; - break; - case 3: - case 4: - random_save_seed(); - exit(0); - break; - default: - if (pos < sizeof(password)-1) - password[pos++] = c; - break; - } - } + ret = process_userpass_input(in, inlen); + } while (ret == 0); + if (ret < 0) + cleanup_exit(0); c_write_str("\r\n"); } @@ -2076,7 +2693,7 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) tried_publickey = 1; i = loadrsakey(cfg.keyfile, &pubkey, password); if (i == 0) { - c_write_str("Couldn't load public key from "); + c_write_str("Couldn't load private key from "); c_write_str(cfg.keyfile); c_write_str(".\r\n"); continue; /* go and try password */ @@ -2165,26 +2782,17 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) * use of the fact that the password is interpreted * as a C string: so we can append a NUL, then some * random data. + * + * One server (a Cisco one) can deal with neither + * SSH1_MSG_IGNORE _nor_ a padded password string. + * For this server we are left with no defences + * against password length sniffing. */ - if (ssh_remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE) { - char string[64]; - char *s; - int len; - - len = strlen(password); - if (len < sizeof(string)) { - s = string; - strcpy(string, password); - len++; /* cover the zero byte */ - while (len < sizeof(string)) { - string[len++] = (char) random_byte(); - } - } else { - s = password; - } - send_packet(pwpkt_type, PKT_INT, len, - PKT_DATA, s, len, PKT_END); - } else { + if (!(ssh_remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) { + /* + * The server can deal with SSH1_MSG_IGNORE, so + * we can use the primary defence. + */ int bottom, top, pwlen, i; char *randomstr; @@ -2216,7 +2824,45 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) PKT_STR, randomstr, PKT_END); } } + logevent("Sending password with camouflage packets"); ssh_pkt_defersend(); + } + else if (!(ssh_remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) { + /* + * The server can't deal with SSH1_MSG_IGNORE + * but can deal with padded passwords, so we + * can use the secondary defence. + */ + char string[64]; + char *s; + int len; + + len = strlen(password); + if (len < sizeof(string)) { + s = string; + strcpy(string, password); + len++; /* cover the zero byte */ + while (len < sizeof(string)) { + string[len++] = (char) random_byte(); + } + } else { + s = password; + } + logevent("Sending length-padded password"); + send_packet(pwpkt_type, PKT_INT, len, + PKT_DATA, s, len, PKT_END); + } else { + /* + * The server has _both_ + * BUG_CHOKES_ON_SSH1_IGNORE and + * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is + * therefore nothing we can do. + */ + int len; + len = strlen(password); + logevent("Sending unpadded password"); + send_packet(pwpkt_type, PKT_INT, len, + PKT_DATA, password, len, PKT_END); } } else { send_packet(pwpkt_type, PKT_STR, password, PKT_END); @@ -2247,31 +2893,64 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) void sshfwd_close(struct ssh_channel *c) { if (c && !c->closes) { - if (ssh_version == 1) { - send_packet(SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid, - PKT_END); - } else { - ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE); - ssh2_pkt_adduint32(c->remoteid); - ssh2_pkt_send(); + /* + * If the channel's remoteid is -1, we have sent + * CHANNEL_OPEN for this channel, but it hasn't even been + * acknowledged by the server. So we must set a close flag + * on it now, and then when the server acks the channel + * open, we can close it then. + */ + if (((int)c->remoteid) != -1) { + if (ssh_version == 1) { + send_packet(SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid, + PKT_END); + } else { + ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE); + ssh2_pkt_adduint32(c->remoteid); + ssh2_pkt_send(); + } } - c->closes = 1; + c->closes = 1; /* sent MSG_CLOSE */ if (c->type == CHAN_X11) { c->u.x11.s = NULL; - logevent("X11 connection terminated"); + logevent("Forwarded X11 connection terminated"); + } else if (c->type == CHAN_SOCKDATA || + c->type == CHAN_SOCKDATA_DORMANT) { + c->u.pfd.s = NULL; + logevent("Forwarded port closed"); } } } -void sshfwd_write(struct ssh_channel *c, char *buf, int len) +int sshfwd_write(struct ssh_channel *c, char *buf, int len) { if (ssh_version == 1) { send_packet(SSH1_MSG_CHANNEL_DATA, PKT_INT, c->remoteid, PKT_INT, len, PKT_DATA, buf, len, PKT_END); + /* + * In SSH1 we can return 0 here - implying that forwarded + * connections are never individually throttled - because + * the only circumstance that can cause throttling will be + * the whole SSH connection backing up, in which case + * _everything_ will be throttled as a whole. + */ + return 0; } else { ssh2_add_channel_data(c, buf, len); - ssh2_try_send(c); + return ssh2_try_send(c); + } +} + +void sshfwd_unthrottle(struct ssh_channel *c, int bufsize) +{ + if (ssh_version == 1) { + if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) { + c->v.v1.throttling = 0; + ssh1_throttle(-1); + } + } else { + ssh2_set_window(c, OUR_V2_WINSIZE - bufsize); } } @@ -2332,10 +3011,124 @@ static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) } } + { + char type; + static char *e; + int n; + int sport,dport,sserv,dserv; + char sports[256], dports[256], host[256]; + char buf[1024]; + struct servent *se; + + ssh_rportfwds = newtree234(ssh_rportcmp_ssh1); + /* Add port forwardings. */ + e = cfg.portfwd; + while (*e) { + type = *e++; + n = 0; + while (*e && *e != '\t') + sports[n++] = *e++; + sports[n] = 0; + if (*e == '\t') + e++; + n = 0; + while (*e && *e != ':') + host[n++] = *e++; + host[n] = 0; + if (*e == ':') + e++; + n = 0; + while (*e) + dports[n++] = *e++; + dports[n] = 0; + e++; + dport = atoi(dports); + dserv = 0; + if (dport == 0) { + dserv = 1; + se = getservbyname(dports, NULL); + if (se != NULL) { + dport = ntohs(se->s_port); + } else { + sprintf(buf, + "Service lookup failed for destination port \"%s\"", + dports); + logevent(buf); + } + } + sport = atoi(sports); + sserv = 0; + if (sport == 0) { + sserv = 1; + se = getservbyname(sports, NULL); + if (se != NULL) { + sport = ntohs(se->s_port); + } else { + sprintf(buf, + "Service lookup failed for source port \"%s\"", + sports); + logevent(buf); + } + } + if (sport && dport) { + if (type == 'L') { + pfd_addforward(host, dport, sport); + sprintf(buf, "Local port %.*s%.*s%d%.*s forwarding to" + " %s:%.*s%.*s%d%.*s", + sserv ? strlen(sports) : 0, sports, + sserv, "(", sport, sserv, ")", + host, + dserv ? strlen(dports) : 0, dports, + dserv, "(", dport, dserv, ")"); + logevent(buf); + } else { + struct ssh_rportfwd *pf; + pf = smalloc(sizeof(*pf)); + strcpy(pf->dhost, host); + pf->dport = dport; + if (add234(ssh_rportfwds, pf) != pf) { + sprintf(buf, + "Duplicate remote port forwarding to %s:%d", + host, dport); + logevent(buf); + sfree(pf); + } else { + sprintf(buf, "Requesting remote port %.*s%.*s%d%.*s" + " forward to %s:%.*s%.*s%d%.*s", + sserv ? strlen(sports) : 0, sports, + sserv, "(", sport, sserv, ")", + host, + dserv ? strlen(dports) : 0, dports, + dserv, "(", dport, dserv, ")"); + logevent(buf); + send_packet(SSH1_CMSG_PORT_FORWARD_REQUEST, + PKT_INT, sport, + PKT_STR, host, + PKT_INT, dport, + PKT_END); + do { + crReturnV; + } while (!ispkt); + if (pktin.type != SSH1_SMSG_SUCCESS + && pktin.type != SSH1_SMSG_FAILURE) { + bombout(("Protocol confusion")); + crReturnV; + } else if (pktin.type == SSH1_SMSG_FAILURE) { + c_write_str("Server refused port forwarding\r\n"); + ssh_editing = ssh_echoing = 1; + } + logevent("Remote port forwarding enabled"); + } + } + } + } + } + if (!cfg.nopty) { send_packet(SSH1_CMSG_REQUEST_PTY, PKT_STR, cfg.termtype, - PKT_INT, rows, PKT_INT, cols, + PKT_INT, term ? term->rows : 24, + PKT_INT, term ? term->cols : 80, PKT_INT, 0, PKT_INT, 0, PKT_CHAR, 0, PKT_END); ssh_state = SSH_STATE_INTERMED; do { @@ -2372,12 +3165,26 @@ static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) zlib_decompress_init(); } - if (*cfg.remote_cmd_ptr) - send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cfg.remote_cmd_ptr, - PKT_END); - else - send_packet(SSH1_CMSG_EXEC_SHELL, PKT_END); - logevent("Started session"); + /* + * Start the shell or command. + * + * Special case: if the first-choice command is an SSH2 + * subsystem (hence not usable here) and the second choice + * exists, we fall straight back to that. + */ + { + char *cmd = cfg.remote_cmd_ptr; + + if (cfg.ssh_subsys && cfg.remote_cmd_ptr2) { + cmd = cfg.remote_cmd_ptr2; + ssh_fallback_cmd = TRUE; + } + if (*cmd) + send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END); + else + send_packet(SSH1_CMSG_EXEC_SHELL, PKT_END); + logevent("Started session"); + } ssh_state = SSH_STATE_SESSION; if (size_needed) @@ -2385,7 +3192,7 @@ static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) if (eof_needed) ssh_special(TS_EOF); - ldisc_send(NULL, 0); /* cause ldisc to notice changes */ + ldisc_send(NULL, 0, 0); /* cause ldisc to notice changes */ ssh_send_ok = 1; ssh_channels = newtree234(ssh_channelcmp); while (1) { @@ -2394,8 +3201,13 @@ static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) if (pktin.type == SSH1_SMSG_STDOUT_DATA || pktin.type == SSH1_SMSG_STDERR_DATA) { long len = GET_32BIT(pktin.body); - from_backend(pktin.type == SSH1_SMSG_STDERR_DATA, - pktin.body + 4, len); + int bufsize = + from_backend(frontend, pktin.type == SSH1_SMSG_STDERR_DATA, + pktin.body + 4, len); + if (!ssh1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) { + ssh1_stdout_throttling = 1; + ssh1_throttle(+1); + } } else if (pktin.type == SSH1_MSG_DISCONNECT) { ssh_state = SSH_STATE_CLOSED; logevent("Received disconnect request"); @@ -2426,6 +3238,7 @@ static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) c->remoteid = GET_32BIT(pktin.body); c->localid = alloc_channel_id(); c->closes = 0; + c->v.v1.throttling = 0; c->type = CHAN_X11; /* identify channel type */ add234(ssh_channels, c); send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION, @@ -2448,6 +3261,7 @@ static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) c->remoteid = GET_32BIT(pktin.body); c->localid = alloc_channel_id(); c->closes = 0; + c->v.v1.throttling = 0; c->type = CHAN_AGENT; /* identify channel type */ c->u.a.lensofar = 0; add234(ssh_channels, c); @@ -2455,30 +3269,138 @@ static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) PKT_INT, c->remoteid, PKT_INT, c->localid, PKT_END); } + } else if (pktin.type == SSH1_MSG_PORT_OPEN) { + /* Remote side is trying to open a channel to talk to a + * forwarded port. Give them back a local channel number. */ + struct ssh_channel *c; + struct ssh_rportfwd pf; + int hostsize, port; + char host[256], buf[1024]; + char *p, *h, *e; + c = smalloc(sizeof(struct ssh_channel)); + + hostsize = GET_32BIT(pktin.body+4); + for(h = host, p = pktin.body+8; hostsize != 0; hostsize--) { + if (h+1 < host+sizeof(host)) + *h++ = *p; + p++; + } + *h = 0; + port = GET_32BIT(p); + + strcpy(pf.dhost, host); + pf.dport = port; + + if (find234(ssh_rportfwds, &pf, NULL) == NULL) { + sprintf(buf, "Rejected remote port open request for %s:%d", + host, port); + logevent(buf); + send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE, + PKT_INT, GET_32BIT(pktin.body), PKT_END); + } else { + sprintf(buf, "Received remote port open request for %s:%d", + host, port); + logevent(buf); + e = pfd_newconnect(&c->u.pfd.s, host, port, c); + if (e != NULL) { + char buf[256]; + sprintf(buf, "Port open failed: %s", e); + logevent(buf); + sfree(c); + send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE, + PKT_INT, GET_32BIT(pktin.body), + PKT_END); + } else { + c->remoteid = GET_32BIT(pktin.body); + c->localid = alloc_channel_id(); + c->closes = 0; + c->v.v1.throttling = 0; + c->type = CHAN_SOCKDATA; /* identify channel type */ + add234(ssh_channels, c); + send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION, + PKT_INT, c->remoteid, PKT_INT, + c->localid, PKT_END); + logevent("Forwarded port opened successfully"); + } + } + + } else if (pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) { + unsigned int remoteid = GET_32BIT(pktin.body); + unsigned int localid = GET_32BIT(pktin.body+4); + struct ssh_channel *c; + + c = find234(ssh_channels, &remoteid, ssh_channelfind); + if (c && c->type == CHAN_SOCKDATA_DORMANT) { + c->remoteid = localid; + c->type = CHAN_SOCKDATA; + c->v.v1.throttling = 0; + pfd_confirm(c->u.pfd.s); + } + + if (c && c->closes) { + /* + * We have a pending close on this channel, + * which we decided on before the server acked + * the channel open. So now we know the + * remoteid, we can close it again. + */ + send_packet(SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid, + PKT_END); + } + + } else if (pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) { + unsigned int remoteid = GET_32BIT(pktin.body); + unsigned int localid = GET_32BIT(pktin.body+4); + struct ssh_channel *c; + + c = find234(ssh_channels, &remoteid, ssh_channelfind); + if (c && c->type == CHAN_SOCKDATA_DORMANT) { + logevent("Forwarded connection refused by server"); + pfd_close(c->u.pfd.s); + del234(ssh_channels, c); + sfree(c); + } + } else if (pktin.type == SSH1_MSG_CHANNEL_CLOSE || pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) { /* Remote side closes a channel. */ unsigned i = GET_32BIT(pktin.body); struct ssh_channel *c; c = find234(ssh_channels, &i, ssh_channelfind); - if (c) { + if (c && ((int)c->remoteid) != -1) { int closetype; closetype = (pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2); - if (!(c->closes & closetype)) - send_packet(pktin.type, PKT_INT, c->remoteid, - PKT_END); + if ((c->closes == 0) && (c->type == CHAN_X11)) { - logevent("X11 connection closed"); + logevent("Forwarded X11 connection terminated"); assert(c->u.x11.s != NULL); x11_close(c->u.x11.s); c->u.x11.s = NULL; } - c->closes |= closetype; - if (c->closes == 3) { + if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) { + logevent("Forwarded port closed"); + assert(c->u.pfd.s != NULL); + pfd_close(c->u.pfd.s); + c->u.pfd.s = NULL; + } + + c->closes |= (closetype << 2); /* seen this message */ + if (!(c->closes & closetype)) { + send_packet(pktin.type, PKT_INT, c->remoteid, + PKT_END); + c->closes |= closetype; /* sent it too */ + } + + if (c->closes == 15) { del234(ssh_channels, c); sfree(c); } + } else { + bombout(("Received CHANNEL_CLOSE%s for %s channel %d\n", + pktin.type == SSH1_MSG_CHANNEL_CLOSE ? "" : + "_CONFIRMATION", c ? "half-open" : "nonexistent", + i)); } } else if (pktin.type == SSH1_MSG_CHANNEL_DATA) { /* Data sent down one of our channels. */ @@ -2488,9 +3410,13 @@ static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) struct ssh_channel *c; c = find234(ssh_channels, &i, ssh_channelfind); if (c) { + int bufsize; switch (c->type) { case CHAN_X11: - x11_send(c->u.x11.s, p, len); + bufsize = x11_send(c->u.x11.s, p, len); + break; + case CHAN_SOCKDATA: + bufsize = pfd_send(c->u.pfd.s, p, len); break; case CHAN_AGENT: /* Data for an agent message. Buffer it. */ @@ -2543,8 +3469,13 @@ static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) c->u.a.lensofar = 0; } } + bufsize = 0; /* agent channels never back up */ break; } + if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) { + c->v.v1.throttling = 1; + ssh1_throttle(+1); + } } } else if (pktin.type == SSH1_SMSG_SUCCESS) { /* may be from EXEC_SHELL on some servers */ @@ -2552,7 +3483,21 @@ static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) /* may be from EXEC_SHELL on some servers * if no pty is available or in other odd cases. Ignore */ } else if (pktin.type == SSH1_SMSG_EXIT_STATUS) { + char buf[100]; + ssh_exitcode = GET_32BIT(pktin.body); + sprintf(buf, "Server sent command exit status %d", + ssh_exitcode); + logevent(buf); send_packet(SSH1_CMSG_EXIT_CONFIRMATION, PKT_END); + /* + * In case `helpful' firewalls or proxies tack + * extra human-readable text on the end of the + * session which we might mistake for another + * encrypted packet, we close the session once + * we've sent EXIT_CONFIRMATION. + */ + ssh_state = SSH_STATE_CLOSED; + crReturnV; } else { bombout(("Strange packet received: type %d", pktin.type)); crReturnV; @@ -2608,14 +3553,16 @@ static void ssh2_mkkey(Bignum K, char *H, char *sessid, char chr, SHA_State s; /* First 20 bytes. */ SHA_Init(&s); - sha_mpint(&s, K); + if (!(ssh_remote_bugs & BUG_SSH2_DERIVEKEY)) + sha_mpint(&s, K); SHA_Bytes(&s, H, 20); SHA_Bytes(&s, &chr, 1); SHA_Bytes(&s, sessid, 20); SHA_Final(&s, keyspace); /* Next 20 bytes. */ SHA_Init(&s); - sha_mpint(&s, K); + if (!(ssh_remote_bugs & BUG_SSH2_DERIVEKEY)) + sha_mpint(&s, K); SHA_Bytes(&s, H, 20); SHA_Bytes(&s, keyspace, 20); SHA_Final(&s, keyspace + 20); @@ -2626,7 +3573,7 @@ static void ssh2_mkkey(Bignum K, char *H, char *sessid, char chr, */ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) { - static int i, j, len, nbits, pbits; + static int i, j, len, nbits, pbits, warn; static char *str; static Bignum p, g, e, f, K; static int kex_init_value, kex_reply_value; @@ -2643,8 +3590,10 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) static void *hkey; /* actual host key */ static unsigned char exchange_hash[20]; static unsigned char keyspace[40]; - static const struct ssh2_ciphers *preferred_cipher; + static int n_preferred_ciphers; + static const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX]; static const struct ssh_compress *preferred_comp; + static int cipherstr_started; static int first_kex; crBegin; @@ -2652,21 +3601,43 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) first_kex = 1; /* - * Set up the preferred cipher and compression. + * Set up the preferred ciphers. (NULL => warn below here) */ - if (cfg.cipher == CIPHER_BLOWFISH) { - preferred_cipher = &ssh2_blowfish; - } else if (cfg.cipher == CIPHER_DES) { - logevent("Single DES not supported in SSH2; using 3DES"); - preferred_cipher = &ssh2_3des; - } else if (cfg.cipher == CIPHER_3DES) { - preferred_cipher = &ssh2_3des; - } else if (cfg.cipher == CIPHER_AES) { - preferred_cipher = &ssh2_aes; - } else { - /* Shouldn't happen, but we do want to initialise to _something_. */ - preferred_cipher = &ssh2_3des; + n_preferred_ciphers = 0; + for (i = 0; i < CIPHER_MAX; i++) { + switch (cfg.ssh_cipherlist[i]) { + case CIPHER_BLOWFISH: + preferred_ciphers[n_preferred_ciphers] = &ssh2_blowfish; + n_preferred_ciphers++; + break; + case CIPHER_DES: + if (cfg.ssh2_des_cbc) { + preferred_ciphers[n_preferred_ciphers] = &ssh2_des; + n_preferred_ciphers++; + } + break; + case CIPHER_3DES: + preferred_ciphers[n_preferred_ciphers] = &ssh2_3des; + n_preferred_ciphers++; + break; + case CIPHER_AES: + preferred_ciphers[n_preferred_ciphers] = &ssh2_aes; + n_preferred_ciphers++; + break; + case CIPHER_WARN: + /* Flag for later. Don't bother if it's the last in + * the list. */ + if (i < CIPHER_MAX - 1) { + preferred_ciphers[n_preferred_ciphers] = NULL; + n_preferred_ciphers++; + } + break; + } } + + /* + * Set up preferred compression. + */ if (cfg.compression) preferred_comp = &ssh_zlib; else @@ -2675,7 +3646,7 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) /* * Be prepared to work around the buggy MAC problem. */ - if (cfg.buggymac || (ssh_remote_bugs & BUG_SSH2_HMAC)) + if (ssh_remote_bugs & BUG_SSH2_HMAC) maclist = buggymacs, nmacs = lenof(buggymacs); else maclist = macs, nmacs = lenof(macs); @@ -2690,6 +3661,9 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) /* List key exchange algorithms. */ ssh2_pkt_addstring_start(); for (i = 0; i < lenof(kex_algs); i++) { + if (kex_algs[i] == &ssh_diffiehellman_gex && + (ssh_remote_bugs & BUG_SSH2_DH_GEX)) + continue; ssh2_pkt_addstring_str(kex_algs[i]->name); if (i < lenof(kex_algs) - 1) ssh2_pkt_addstring_str(","); @@ -2703,24 +3677,28 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) } /* List client->server encryption algorithms. */ ssh2_pkt_addstring_start(); - for (i = 0; i < lenof(ciphers) + 1; i++) { - const struct ssh2_ciphers *c = - i == 0 ? preferred_cipher : ciphers[i - 1]; + cipherstr_started = 0; + for (i = 0; i < n_preferred_ciphers; i++) { + const struct ssh2_ciphers *c = preferred_ciphers[i]; + if (!c) continue; /* warning flag */ for (j = 0; j < c->nciphers; j++) { - ssh2_pkt_addstring_str(c->list[j]->name); - if (i < lenof(ciphers) || j < c->nciphers - 1) + if (cipherstr_started) ssh2_pkt_addstring_str(","); + ssh2_pkt_addstring_str(c->list[j]->name); + cipherstr_started = 1; } } /* List server->client encryption algorithms. */ ssh2_pkt_addstring_start(); - for (i = 0; i < lenof(ciphers) + 1; i++) { - const struct ssh2_ciphers *c = - i == 0 ? preferred_cipher : ciphers[i - 1]; + cipherstr_started = 0; + for (i = 0; i < n_preferred_ciphers; i++) { + const struct ssh2_ciphers *c = preferred_ciphers[i]; + if (!c) continue; /* warning flag */ for (j = 0; j < c->nciphers; j++) { - ssh2_pkt_addstring_str(c->list[j]->name); - if (i < lenof(ciphers) || j < c->nciphers - 1) + if (cipherstr_started) ssh2_pkt_addstring_str(","); + ssh2_pkt_addstring_str(c->list[j]->name); + cipherstr_started = 1; } } /* List client->server MAC algorithms. */ @@ -2792,6 +3770,9 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) pktin.savedpos += 16; /* skip garbage cookie */ ssh2_pkt_getstring(&str, &len); /* key exchange algorithms */ for (i = 0; i < lenof(kex_algs); i++) { + if (kex_algs[i] == &ssh_diffiehellman_gex && + (ssh_remote_bugs & BUG_SSH2_DH_GEX)) + continue; if (in_commasep_string(kex_algs[i]->name, str, len)) { kex = kex_algs[i]; break; @@ -2805,31 +3786,55 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) } } ssh2_pkt_getstring(&str, &len); /* client->server cipher */ - for (i = 0; i < lenof(ciphers) + 1; i++) { - const struct ssh2_ciphers *c = - i == 0 ? preferred_cipher : ciphers[i - 1]; - for (j = 0; j < c->nciphers; j++) { - if (in_commasep_string(c->list[j]->name, str, len)) { - cscipher_tobe = c->list[j]; - break; + warn = 0; + for (i = 0; i < n_preferred_ciphers; i++) { + const struct ssh2_ciphers *c = preferred_ciphers[i]; + if (!c) { + warn = 1; + } else { + for (j = 0; j < c->nciphers; j++) { + if (in_commasep_string(c->list[j]->name, str, len)) { + cscipher_tobe = c->list[j]; + break; + } } } - if (cscipher_tobe) + if (cscipher_tobe) { + if (warn) + askcipher(cscipher_tobe->name, 1); break; + } + } + if (!cscipher_tobe) { + bombout(("Couldn't agree a client-to-server cipher (available: %s)", str)); + crReturn(0); } + ssh2_pkt_getstring(&str, &len); /* server->client cipher */ - for (i = 0; i < lenof(ciphers) + 1; i++) { - const struct ssh2_ciphers *c = - i == 0 ? preferred_cipher : ciphers[i - 1]; - for (j = 0; j < c->nciphers; j++) { - if (in_commasep_string(c->list[j]->name, str, len)) { - sccipher_tobe = c->list[j]; - break; + warn = 0; + for (i = 0; i < n_preferred_ciphers; i++) { + const struct ssh2_ciphers *c = preferred_ciphers[i]; + if (!c) { + warn = 1; + } else { + for (j = 0; j < c->nciphers; j++) { + if (in_commasep_string(c->list[j]->name, str, len)) { + sccipher_tobe = c->list[j]; + break; + } } } - if (sccipher_tobe) + if (sccipher_tobe) { + if (warn) + askcipher(sccipher_tobe->name, 2); break; + } } + if (!sccipher_tobe) { + bombout(("Couldn't agree a server-to-client cipher (available: %s)", str)); + crReturn(0); + } + ssh2_pkt_getstring(&str, &len); /* client->server mac */ for (i = 0; i < nmacs; i++) { if (in_commasep_string(maclist[i]->name, str, len)) { @@ -2886,6 +3891,7 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) */ if (kex == &ssh_diffiehellman_gex) { logevent("Doing Diffie-Hellman group exchange"); + ssh_pkt_ctx |= SSH2_PKTCTX_DHGEX; /* * Work out how big a DH group we will need to allow that * much data. @@ -2906,6 +3912,7 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT; kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY; } else { + ssh_pkt_ctx |= SSH2_PKTCTX_DHGROUP1; dh_setup_group1(); kex_init_value = SSH2_MSG_KEXDH_INIT; kex_reply_value = SSH2_MSG_KEXDH_REPLY; @@ -2950,17 +3957,9 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) #endif hkey = hostkey->newkey(hostkeydata, hostkeylen); - if (!hostkey->verifysig(hkey, sigdata, siglen, exchange_hash, 20)) { - bombout(("Server failed host key check")); - crReturn(0); - } - - /* - * Expect SSH2_MSG_NEWKEYS from server. - */ - crWaitUntil(ispkt); - if (pktin.type != SSH2_MSG_NEWKEYS) { - bombout(("expected new-keys packet from server")); + if (!hkey || + !hostkey->verifysig(hkey, sigdata, siglen, exchange_hash, 20)) { + bombout(("Server's host key did not match the signature supplied")); crReturn(0); } @@ -2987,6 +3986,15 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) ssh2_pkt_send(); /* + * Expect SSH2_MSG_NEWKEYS from server. + */ + crWaitUntil(ispkt); + if (pktin.type != SSH2_MSG_NEWKEYS) { + bombout(("expected new-keys packet from server")); + crReturn(0); + } + + /* * Create and initialise session keys. */ cscipher = cscipher_tobe; @@ -3050,33 +4058,57 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len) { - if (c->v2.outbufsize < c->v2.outbuflen + len) { - c->v2.outbufsize = c->v2.outbuflen + len + 1024; - c->v2.outbuffer = srealloc(c->v2.outbuffer, c->v2.outbufsize); - } - memcpy(c->v2.outbuffer + c->v2.outbuflen, buf, len); - c->v2.outbuflen += len; + bufchain_add(&c->v.v2.outbuffer, buf, len); } /* * Attempt to send data on an SSH2 channel. */ -static void ssh2_try_send(struct ssh_channel *c) +static int ssh2_try_send(struct ssh_channel *c) { - while (c->v2.remwindow > 0 && c->v2.outbuflen > 0) { - unsigned len = c->v2.remwindow; - if (len > c->v2.outbuflen) - len = c->v2.outbuflen; - if (len > c->v2.remmaxpkt) - len = c->v2.remmaxpkt; + while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) { + int len; + void *data; + bufchain_prefix(&c->v.v2.outbuffer, &data, &len); + if ((unsigned)len > c->v.v2.remwindow) + len = c->v.v2.remwindow; + if ((unsigned)len > c->v.v2.remmaxpkt) + len = c->v.v2.remmaxpkt; ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA); ssh2_pkt_adduint32(c->remoteid); ssh2_pkt_addstring_start(); - ssh2_pkt_addstring_data(c->v2.outbuffer, len); + ssh2_pkt_addstring_data(data, len); + ssh2_pkt_send(); + bufchain_consume(&c->v.v2.outbuffer, len); + c->v.v2.remwindow -= len; + } + + /* + * After having sent as much data as we can, return the amount + * still buffered. + */ + return bufchain_size(&c->v.v2.outbuffer); +} + +/* + * Potentially enlarge the window on an SSH2 channel. + */ +static void ssh2_set_window(struct ssh_channel *c, unsigned newwin) +{ + /* + * Never send WINDOW_ADJUST for a channel that the remote side + * already thinks it's closed; there's no point, since it won't + * be sending any more data anyway. + */ + if (c->closes != 0) + return; + + if (newwin > c->v.v2.locwindow) { + ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST); + ssh2_pkt_adduint32(c->remoteid); + ssh2_pkt_adduint32(newwin - c->v.v2.locwindow); ssh2_pkt_send(); - c->v2.outbuflen -= len; - memmove(c->v2.outbuffer, c->v2.outbuffer + len, c->v2.outbuflen); - c->v2.remwindow -= len; + c->v.v2.locwindow = newwin; } } @@ -3085,25 +4117,31 @@ static void ssh2_try_send(struct ssh_channel *c) */ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) { - static unsigned long remote_winsize; - static unsigned long remote_maxpkt; static enum { AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE, - AUTH_PASSWORD + AUTH_PASSWORD, + AUTH_KEYBOARD_INTERACTIVE } method; static enum { AUTH_TYPE_NONE, AUTH_TYPE_PUBLICKEY, AUTH_TYPE_PUBLICKEY_OFFER_LOUD, AUTH_TYPE_PUBLICKEY_OFFER_QUIET, - AUTH_TYPE_PASSWORD + AUTH_TYPE_PASSWORD, + AUTH_TYPE_KEYBOARD_INTERACTIVE, + AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET } type; - static int gotit, need_pw, can_pubkey, can_passwd; - static int tried_pubkey_config, tried_agent; + static int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter; + static int tried_pubkey_config, tried_agent, tried_keyb_inter; + static int kbd_inter_running; static int we_are_in; + static int num_prompts, curr_prompt, echo; static char username[100]; + static int got_username; static char pwprompt[200]; static char password[100]; + static void *publickey_blob; + static int publickey_bloblen; crBegin; @@ -3143,16 +4181,20 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) * the username they will want to be able to get back and * retype it! */ + username[0] = '\0'; + got_username = FALSE; do { - static int pos; - static char c; - /* * Get a username. */ - pos = 0; - if ((flags & FLAG_INTERACTIVE) && !*cfg.username) { - if (ssh_get_line) { + if (got_username && !cfg.change_username) { + /* + * We got a username last time round this loop, and + * with change_username turned off we don't try to get + * it again. + */ + } else if ((flags & FLAG_INTERACTIVE) && !*cfg.username) { + if (ssh_get_line && !ssh_getline_pw_only) { if (!ssh_get_line("login as: ", username, sizeof(username), FALSE)) { /* @@ -3164,64 +4206,37 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) crReturnV; } } else { + static int ret; c_write_str("login as: "); ssh_send_ok = 1; - while (pos >= 0) { + setup_userpass_input(username, sizeof(username), 1); + do { crWaitUntilV(!ispkt); - while (inlen--) - switch (c = *in++) { - case 10: - case 13: - username[pos] = 0; - pos = -1; - break; - case 8: - case 127: - if (pos > 0) { - c_write_str("\b \b"); - pos--; - } - break; - case 21: - case 27: - while (pos > 0) { - c_write_str("\b \b"); - pos--; - } - break; - case 3: - case 4: - random_save_seed(); - exit(0); - break; - default: - if (((c >= ' ' && c <= '~') || - ((unsigned char) c >= 160)) - && pos < sizeof(username)-1) { - username[pos++] = c; - c_write(&c, 1); - } - break; - } - } + ret = process_userpass_input(in, inlen); + } while (ret == 0); + if (ret < 0) + cleanup_exit(0); } c_write_str("\r\n"); username[strcspn(username, "\n\r")] = '\0'; } else { char stuff[200]; - strncpy(username, cfg.username, 99); - username[99] = '\0'; + strncpy(username, cfg.username, sizeof(username)); + username[sizeof(username)-1] = '\0'; if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) { sprintf(stuff, "Using username \"%s\".\r\n", username); c_write_str(stuff); } } + got_username = TRUE; /* * Send an authentication request using method "none": (a) * just in case it succeeds, and (b) so that we know what * authentication methods we can usefully try next. */ + ssh_pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK; + ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST); ssh2_pkt_addstring(username); ssh2_pkt_addstring("ssh-connection"); /* service requested */ @@ -3233,6 +4248,27 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) tried_pubkey_config = FALSE; tried_agent = FALSE; + tried_keyb_inter = FALSE; + kbd_inter_running = FALSE; + /* Load the pub half of cfg.keyfile so we notice if it's in Pageant */ + if (*cfg.keyfile) { + int keytype; + logeventf("Reading private key file \"%.150s\"", cfg.keyfile); + keytype = key_type(cfg.keyfile); + if (keytype == SSH_KEYTYPE_SSH2) + publickey_blob = ssh2_userkey_loadpub(cfg.keyfile, NULL, + &publickey_bloblen); + else { + char msgbuf[256]; + logeventf("Unable to use this key file (%s)", + key_type_to_str(keytype)); + sprintf(msgbuf, "Unable to use key file \"%.150s\" (%s)\r\n", + cfg.keyfile, key_type_to_str(keytype)); + c_write_str(msgbuf); + publickey_blob = NULL; + } + } else + publickey_blob = NULL; while (1) { /* @@ -3264,9 +4300,19 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) break; } - if (pktin.type != SSH2_MSG_USERAUTH_FAILURE) { - bombout( - ("Strange packet received during authentication: type %d", + if (kbd_inter_running && + pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) { + /* + * This is either a further set-of-prompts packet + * in keyboard-interactive authentication, or it's + * the same one and we came back here with `gotit' + * set. In the former case, we must reset the + * curr_prompt variable. + */ + if (!gotit) + curr_prompt = 0; + } else if (pktin.type != SSH2_MSG_USERAUTH_FAILURE) { + bombout(("Strange packet received during authentication: type %d", pktin.type)); crReturnV; } @@ -3278,10 +4324,11 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) * we can look at the string in it and know what we can * helpfully try next. */ - { + if (pktin.type == SSH2_MSG_USERAUTH_FAILURE) { char *methods; int methlen; ssh2_pkt_getstring(&methods, &methlen); + kbd_inter_running = FALSE; if (!ssh2_pkt_getbool()) { /* * We have received an unequivocal Access @@ -3311,6 +4358,8 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) if (type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD) c_write_str("Server refused our key\r\n"); logevent("Server refused public key"); + } else if (type == AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) { + /* server declined keyboard-interactive; ignore */ } else { c_write_str("Access denied\r\n"); logevent("Access denied"); @@ -3328,12 +4377,23 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) in_commasep_string("publickey", methods, methlen); can_passwd = in_commasep_string("password", methods, methlen); + can_keyb_inter = cfg.try_ki_auth && + in_commasep_string("keyboard-interactive", methods, methlen); } method = 0; + ssh_pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK; - if (!method && can_pubkey && agent_exists() && !tried_agent) { - /* + /* + * Most password/passphrase prompts will be + * non-echoing, so we set this to 0 by default. + * Exception is that some keyboard-interactive prompts + * can be echoing, in which case we'll set this to 1. + */ + echo = 0; + + if (!method && can_pubkey && agent_exists() && !tried_agent) { + /* * Attempt public-key authentication using Pageant. */ static unsigned char request[5], *response, *p; @@ -3342,6 +4402,9 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) static int authed = FALSE; void *r; + ssh_pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK; + ssh_pkt_ctx |= SSH2_PKTCTX_PUBLICKEY; + tried_agent = TRUE; logevent("Pageant is running. Requesting keys."); @@ -3366,6 +4429,7 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) static int pklen, alglen, commentlen; static int siglen, retlen, len; static char *q, *agentreq, *ret; + void *vret; { char buf[64]; @@ -3374,6 +4438,12 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) } pklen = GET_32BIT(p); p += 4; + if (publickey_blob && + pklen == publickey_bloblen && + !memcmp(p, publickey_blob, publickey_bloblen)) { + logevent("This key matches configured key file"); + tried_pubkey_config = 1; + } pkblob = p; p += pklen; alglen = GET_32BIT(pkblob); @@ -3444,15 +4514,14 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) q += pktout.length - 5; /* And finally the (zero) flags word. */ PUT_32BIT(q, 0); - agent_query(agentreq, len + 4, &ret, &retlen); + agent_query(agentreq, len + 4, &vret, &retlen); + ret = vret; sfree(agentreq); if (ret) { if (ret[4] == SSH2_AGENT_SIGN_RESPONSE) { logevent("Sending Pageant's response"); - ssh2_pkt_addstring_start(); - ssh2_pkt_addstring_data(ret + 9, - GET_32BIT(ret + - 5)); + ssh2_add_sigblob(pkblob, pklen, + ret + 9, GET_32BIT(ret + 5)); ssh2_pkt_send(); authed = TRUE; break; @@ -3468,7 +4537,7 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) } } - if (!method && can_pubkey && *cfg.keyfile + if (!method && can_pubkey && publickey_blob && !tried_pubkey_config) { unsigned char *pub_blob; char *algorithm, *comment; @@ -3476,6 +4545,9 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) tried_pubkey_config = TRUE; + ssh_pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK; + ssh_pkt_ctx |= SSH2_PKTCTX_PUBLICKEY; + /* * Try the public key supplied in the configuration. * @@ -3523,8 +4595,93 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) } } + if (!method && can_keyb_inter && !tried_keyb_inter) { + method = AUTH_KEYBOARD_INTERACTIVE; + type = AUTH_TYPE_KEYBOARD_INTERACTIVE; + tried_keyb_inter = TRUE; + + ssh_pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK; + ssh_pkt_ctx |= SSH2_PKTCTX_KBDINTER; + + ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST); + ssh2_pkt_addstring(username); + ssh2_pkt_addstring("ssh-connection"); /* service requested */ + ssh2_pkt_addstring("keyboard-interactive"); /* method */ + ssh2_pkt_addstring(""); /* lang */ + ssh2_pkt_addstring(""); + ssh2_pkt_send(); + + crWaitUntilV(ispkt); + if (pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) { + if (pktin.type == SSH2_MSG_USERAUTH_FAILURE) + gotit = TRUE; + logevent("Keyboard-interactive authentication refused"); + type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET; + continue; + } + + kbd_inter_running = TRUE; + curr_prompt = 0; + } + + if (kbd_inter_running) { + method = AUTH_KEYBOARD_INTERACTIVE; + type = AUTH_TYPE_KEYBOARD_INTERACTIVE; + tried_keyb_inter = TRUE; + + ssh_pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK; + ssh_pkt_ctx |= SSH2_PKTCTX_KBDINTER; + + if (curr_prompt == 0) { + /* + * We've got a fresh USERAUTH_INFO_REQUEST. + * Display header data, and start going through + * the prompts. + */ + char *name, *inst, *lang; + int name_len, inst_len, lang_len; + + ssh2_pkt_getstring(&name, &name_len); + ssh2_pkt_getstring(&inst, &inst_len); + ssh2_pkt_getstring(&lang, &lang_len); + if (name_len > 0) { + c_write_untrusted(name, name_len); + c_write_str("\r\n"); + } + if (inst_len > 0) { + c_write_untrusted(inst, inst_len); + c_write_str("\r\n"); + } + num_prompts = ssh2_pkt_getuint32(); + } + + /* + * If there are prompts remaining in the packet, + * display one and get a response. + */ + if (curr_prompt < num_prompts) { + char *prompt; + int prompt_len; + + ssh2_pkt_getstring(&prompt, &prompt_len); + if (prompt_len > 0) { + strncpy(pwprompt, prompt, sizeof(pwprompt)); + pwprompt[prompt_len < sizeof(pwprompt) ? + prompt_len : sizeof(pwprompt)-1] = '\0'; + } else { + strcpy(pwprompt, + ": "); + } + echo = ssh2_pkt_getbool(); + need_pw = TRUE; + } else + need_pw = FALSE; + } + if (!method && can_passwd) { method = AUTH_PASSWORD; + ssh_pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK; + ssh_pkt_ctx |= SSH2_PKTCTX_PASSWORD; sprintf(pwprompt, "%.90s@%.90s's password: ", username, savedhost); need_pw = TRUE; @@ -3546,47 +4703,23 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) ("No more passwords available to try"); ssh2_pkt_addstring("en"); /* language tag */ ssh2_pkt_send(); + logevent("Unable to authenticate"); connection_fatal("Unable to authenticate"); ssh_state = SSH_STATE_CLOSED; crReturnV; } } else { - static int pos = 0; - static char c; - - c_write_str(pwprompt); + static int ret; + c_write_untrusted(pwprompt, strlen(pwprompt)); ssh_send_ok = 1; - pos = 0; - while (pos >= 0) { + setup_userpass_input(password, sizeof(password), echo); + do { crWaitUntilV(!ispkt); - while (inlen--) - switch (c = *in++) { - case 10: - case 13: - password[pos] = 0; - pos = -1; - break; - case 8: - case 127: - if (pos > 0) - pos--; - break; - case 21: - case 27: - pos = 0; - break; - case 3: - case 4: - random_save_seed(); - exit(0); - break; - default: - if (pos < sizeof(password)-1) - password[pos++] = c; - break; - } - } + ret = process_userpass_input(in, inlen); + } while (ret == 0); + if (ret < 0) + cleanup_exit(0); c_write_str("\r\n"); } } @@ -3614,8 +4747,8 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) ssh2_pkt_send(); type = AUTH_TYPE_NONE; } else { - unsigned char *blob, *sigdata; - int blob_len, sigdata_len; + unsigned char *pkblob, *sigblob, *sigdata; + int pkblob_len, sigblob_len, sigdata_len; /* * We have loaded the private key and the server @@ -3628,10 +4761,9 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) ssh2_pkt_addstring("publickey"); /* method */ ssh2_pkt_addbool(TRUE); ssh2_pkt_addstring(key->alg->name); - blob = key->alg->public_blob(key->data, &blob_len); + pkblob = key->alg->public_blob(key->data, &pkblob_len); ssh2_pkt_addstring_start(); - ssh2_pkt_addstring_data(blob, blob_len); - sfree(blob); + ssh2_pkt_addstring_data(pkblob, pkblob_len); /* * The data to be signed is: @@ -3647,12 +4779,12 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) memcpy(sigdata + 4, ssh2_session_id, 20); memcpy(sigdata + 24, pktout.data + 5, pktout.length - 5); - blob = - key->alg->sign(key->data, sigdata, sigdata_len, - &blob_len); - ssh2_pkt_addstring_start(); - ssh2_pkt_addstring_data(blob, blob_len); - sfree(blob); + sigblob = key->alg->sign(key->data, sigdata, + sigdata_len, &sigblob_len); + ssh2_add_sigblob(pkblob, pkblob_len, + sigblob, sigblob_len); + sfree(pkblob); + sfree(sigblob); sfree(sigdata); ssh2_pkt_send(); @@ -3715,6 +4847,30 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) ssh_pkt_defersend(); logevent("Sent password"); type = AUTH_TYPE_PASSWORD; + } else if (method == AUTH_KEYBOARD_INTERACTIVE) { + if (curr_prompt == 0) { + ssh2_pkt_init(SSH2_MSG_USERAUTH_INFO_RESPONSE); + ssh2_pkt_adduint32(num_prompts); + } + if (need_pw) { /* only add pw if we just got one! */ + ssh2_pkt_addstring(password); + memset(password, 0, sizeof(password)); + curr_prompt++; + } + if (curr_prompt >= num_prompts) { + ssh2_pkt_send(); + } else { + /* + * If there are prompts remaining, we set + * `gotit' so that we won't attempt to get + * another packet. Then we go back round the + * loop and will end up retrieving another + * prompt out of the existing packet. Funky or + * what? + */ + gotit = TRUE; + } + type = AUTH_TYPE_KEYBOARD_INTERACTIVE; } else { c_write_str ("No supported authentication methods left to try!\r\n"); @@ -3747,7 +4903,8 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN); ssh2_pkt_addstring("session"); ssh2_pkt_adduint32(mainchan->localid); - ssh2_pkt_adduint32(0x8000UL); /* our window size */ + mainchan->v.v2.locwindow = OUR_V2_WINSIZE; + ssh2_pkt_adduint32(mainchan->v.v2.locwindow); /* our window size */ ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */ ssh2_pkt_send(); crWaitUntilV(ispkt); @@ -3763,10 +4920,9 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) mainchan->remoteid = ssh2_pkt_getuint32(); mainchan->type = CHAN_MAINSESSION; mainchan->closes = 0; - mainchan->v2.remwindow = ssh2_pkt_getuint32(); - mainchan->v2.remmaxpkt = ssh2_pkt_getuint32(); - mainchan->v2.outbuffer = NULL; - mainchan->v2.outbuflen = mainchan->v2.outbufsize = 0; + mainchan->v.v2.remwindow = ssh2_pkt_getuint32(); + mainchan->v.v2.remmaxpkt = ssh2_pkt_getuint32(); + bufchain_init(&mainchan->v.v2.outbuffer); add234(ssh_channels, mainchan); logevent("Opened channel for session"); @@ -3795,13 +4951,14 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) c = find234(ssh_channels, &i, ssh_channelfind); if (!c) continue; /* nonexistent channel */ - c->v2.remwindow += ssh2_pkt_getuint32(); + c->v.v2.remwindow += ssh2_pkt_getuint32(); } } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST); if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) { if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) { - bombout(("Server got confused by X11 forwarding request")); + bombout(("Unexpected response to X11 forwarding request:" + " packet type %d", pktin.type)); crReturnV; } logevent("X11 forwarding refused"); @@ -3812,6 +4969,139 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) } /* + * Enable port forwardings. + */ + { + static char *e; /* preserve across crReturn */ + char type; + int n; + int sport,dport,sserv,dserv; + char sports[256], dports[256], host[256]; + char buf[1024]; + struct servent *se; + + ssh_rportfwds = newtree234(ssh_rportcmp_ssh2); + /* Add port forwardings. */ + e = cfg.portfwd; + while (*e) { + type = *e++; + n = 0; + while (*e && *e != '\t') + sports[n++] = *e++; + sports[n] = 0; + if (*e == '\t') + e++; + n = 0; + while (*e && *e != ':') + host[n++] = *e++; + host[n] = 0; + if (*e == ':') + e++; + n = 0; + while (*e) + dports[n++] = *e++; + dports[n] = 0; + e++; + dport = atoi(dports); + dserv = 0; + if (dport == 0) { + dserv = 1; + se = getservbyname(dports, NULL); + if (se != NULL) { + dport = ntohs(se->s_port); + } else { + sprintf(buf, + "Service lookup failed for destination port \"%s\"", + dports); + logevent(buf); + } + } + sport = atoi(sports); + sserv = 0; + if (sport == 0) { + sserv = 1; + se = getservbyname(sports, NULL); + if (se != NULL) { + sport = ntohs(se->s_port); + } else { + sprintf(buf, + "Service lookup failed for source port \"%s\"", + sports); + logevent(buf); + } + } + if (sport && dport) { + if (type == 'L') { + pfd_addforward(host, dport, sport); + sprintf(buf, "Local port %.*s%.*s%d%.*s forwarding to" + " %s:%.*s%.*s%d%.*s", + sserv ? strlen(sports) : 0, sports, + sserv, "(", sport, sserv, ")", + host, + dserv ? strlen(dports) : 0, dports, + dserv, "(", dport, dserv, ")"); + logevent(buf); + } else { + struct ssh_rportfwd *pf; + pf = smalloc(sizeof(*pf)); + strcpy(pf->dhost, host); + pf->dport = dport; + pf->sport = sport; + if (add234(ssh_rportfwds, pf) != pf) { + sprintf(buf, + "Duplicate remote port forwarding to %s:%d", + host, dport); + logevent(buf); + sfree(pf); + } else { + sprintf(buf, "Requesting remote port %.*s%.*s%d%.*s" + " forward to %s:%.*s%.*s%d%.*s", + sserv ? strlen(sports) : 0, sports, + sserv, "(", sport, sserv, ")", + host, + dserv ? strlen(dports) : 0, dports, + dserv, "(", dport, dserv, ")"); + logevent(buf); + ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST); + ssh2_pkt_addstring("tcpip-forward"); + ssh2_pkt_addbool(1);/* want reply */ + if (cfg.rport_acceptall) + ssh2_pkt_addstring("0.0.0.0"); + else + ssh2_pkt_addstring("127.0.0.1"); + ssh2_pkt_adduint32(sport); + ssh2_pkt_send(); + + do { + crWaitUntilV(ispkt); + if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) { + unsigned i = ssh2_pkt_getuint32(); + struct ssh_channel *c; + c = find234(ssh_channels, &i, ssh_channelfind); + if (!c) + continue;/* nonexistent channel */ + c->v.v2.remwindow += ssh2_pkt_getuint32(); + } + } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST); + + if (pktin.type != SSH2_MSG_REQUEST_SUCCESS) { + if (pktin.type != SSH2_MSG_REQUEST_FAILURE) { + bombout(("Unexpected response to port " + "forwarding request: packet type %d", + pktin.type)); + crReturnV; + } + logevent("Server refused this port forwarding"); + } else { + logevent("Remote port forwarding enabled"); + } + } + } + } + } + } + + /* * Potentially enable agent forwarding. */ if (cfg.agentfwd && agent_exists()) { @@ -3830,14 +5120,14 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) c = find234(ssh_channels, &i, ssh_channelfind); if (!c) continue; /* nonexistent channel */ - c->v2.remwindow += ssh2_pkt_getuint32(); + c->v.v2.remwindow += ssh2_pkt_getuint32(); } } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST); if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) { if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) { - bombout( - ("Server got confused by agent forwarding request")); + bombout(("Unexpected response to agent forwarding request:" + " packet type %d", pktin.type)); crReturnV; } logevent("Agent forwarding refused"); @@ -3856,8 +5146,8 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) ssh2_pkt_addstring("pty-req"); ssh2_pkt_addbool(1); /* want reply */ ssh2_pkt_addstring(cfg.termtype); - ssh2_pkt_adduint32(cols); - ssh2_pkt_adduint32(rows); + ssh2_pkt_adduint32(term ? term->cols : 80); + ssh2_pkt_adduint32(term ? term->rows : 24); ssh2_pkt_adduint32(0); /* pixel width */ ssh2_pkt_adduint32(0); /* pixel height */ ssh2_pkt_addstring_start(); @@ -3873,13 +5163,14 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) c = find234(ssh_channels, &i, ssh_channelfind); if (!c) continue; /* nonexistent channel */ - c->v2.remwindow += ssh2_pkt_getuint32(); + c->v.v2.remwindow += ssh2_pkt_getuint32(); } } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST); if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) { if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) { - bombout(("Server got confused by pty request")); + bombout(("Unexpected response to pty request:" + " packet type %d", pktin.type)); crReturnV; } c_write_str("Server refused to allocate pty\r\n"); @@ -3892,43 +5183,71 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) } /* - * Start a shell or a remote command. + * Start a shell or a remote command. We may have to attempt + * this twice if the config data has provided a second choice + * of command. */ - ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST); - ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */ - if (cfg.ssh_subsys) { - ssh2_pkt_addstring("subsystem"); - ssh2_pkt_addbool(1); /* want reply */ - ssh2_pkt_addstring(cfg.remote_cmd_ptr); - } else if (*cfg.remote_cmd_ptr) { - ssh2_pkt_addstring("exec"); - ssh2_pkt_addbool(1); /* want reply */ - ssh2_pkt_addstring(cfg.remote_cmd_ptr); - } else { - ssh2_pkt_addstring("shell"); - ssh2_pkt_addbool(1); /* want reply */ - } - ssh2_pkt_send(); - do { - crWaitUntilV(ispkt); - if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) { - unsigned i = ssh2_pkt_getuint32(); - struct ssh_channel *c; - c = find234(ssh_channels, &i, ssh_channelfind); - if (!c) - continue; /* nonexistent channel */ - c->v2.remwindow += ssh2_pkt_getuint32(); + while (1) { + int subsys; + char *cmd; + + if (ssh_fallback_cmd) { + subsys = cfg.ssh_subsys2; + cmd = cfg.remote_cmd_ptr2; + } else { + subsys = cfg.ssh_subsys; + cmd = cfg.remote_cmd_ptr; + } + + ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST); + ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */ + if (subsys) { + ssh2_pkt_addstring("subsystem"); + ssh2_pkt_addbool(1); /* want reply */ + ssh2_pkt_addstring(cmd); + } else if (*cmd) { + ssh2_pkt_addstring("exec"); + ssh2_pkt_addbool(1); /* want reply */ + ssh2_pkt_addstring(cmd); + } else { + ssh2_pkt_addstring("shell"); + ssh2_pkt_addbool(1); /* want reply */ } - } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST); - if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) { - if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) { - bombout(("Server got confused by shell/command request")); + ssh2_pkt_send(); + do { + crWaitUntilV(ispkt); + if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) { + unsigned i = ssh2_pkt_getuint32(); + struct ssh_channel *c; + c = find234(ssh_channels, &i, ssh_channelfind); + if (!c) + continue; /* nonexistent channel */ + c->v.v2.remwindow += ssh2_pkt_getuint32(); + } + } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST); + if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) { + if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) { + bombout(("Unexpected response to shell/command request:" + " packet type %d", pktin.type)); + crReturnV; + } + /* + * We failed to start the command. If this is the + * fallback command, we really are finished; if it's + * not, and if the fallback command exists, try falling + * back to it before complaining. + */ + if (!ssh_fallback_cmd && cfg.remote_cmd_ptr2 != NULL) { + logevent("Primary command failed; attempting fallback"); + ssh_fallback_cmd = TRUE; + continue; + } + bombout(("Server refused to start a shell/command")); crReturnV; + } else { + logevent("Started a shell/command"); } - bombout(("Server refused to start a shell/command")); - crReturnV; - } else { - logevent("Started a shell/command"); + break; } ssh_state = SSH_STATE_SESSION; @@ -3940,7 +5259,7 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) /* * Transfer data! */ - ldisc_send(NULL, 0); /* cause ldisc to notice changes */ + ldisc_send(NULL, 0, 0); /* cause ldisc to notice changes */ ssh_send_ok = 1; while (1) { static int try_send; @@ -3961,14 +5280,20 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) continue; /* extended but not stderr */ ssh2_pkt_getstring(&data, &length); if (data) { + int bufsize; + c->v.v2.locwindow -= length; switch (c->type) { case CHAN_MAINSESSION: - from_backend(pktin.type == - SSH2_MSG_CHANNEL_EXTENDED_DATA, data, - length); + bufsize = + from_backend(frontend, pktin.type == + SSH2_MSG_CHANNEL_EXTENDED_DATA, + data, length); break; case CHAN_X11: - x11_send(c->u.x11.s, data, length); + bufsize = x11_send(c->u.x11.s, data, length); + break; + case CHAN_SOCKDATA: + bufsize = pfd_send(c->u.pfd.s, data, length); break; case CHAN_AGENT: while (length > 0) { @@ -4018,24 +5343,20 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) c->u.a.lensofar = 0; } } + bufsize = 0; break; } /* - * Enlarge the window again at the remote - * side, just in case it ever runs down and - * they fail to send us any more data. + * If we are not buffering too much data, + * enlarge the window again at the remote side. */ - ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST); - ssh2_pkt_adduint32(c->remoteid); - ssh2_pkt_adduint32(length); - ssh2_pkt_send(); + if (bufsize < OUR_V2_WINSIZE) + ssh2_set_window(c, OUR_V2_WINSIZE - bufsize); } } else if (pktin.type == SSH2_MSG_DISCONNECT) { ssh_state = SSH_STATE_CLOSED; logevent("Received disconnect message"); crReturnV; - } else if (pktin.type == SSH2_MSG_CHANNEL_REQUEST) { - continue; /* exit status et al; ignore (FIXME?) */ } else if (pktin.type == SSH2_MSG_CHANNEL_EOF) { unsigned i = ssh2_pkt_getuint32(); struct ssh_channel *c; @@ -4053,42 +5374,69 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) sshfwd_close(c); } else if (c->type == CHAN_AGENT) { sshfwd_close(c); + } else if (c->type == CHAN_SOCKDATA) { + pfd_close(c->u.pfd.s); + sshfwd_close(c); } } else if (pktin.type == SSH2_MSG_CHANNEL_CLOSE) { unsigned i = ssh2_pkt_getuint32(); struct ssh_channel *c; c = find234(ssh_channels, &i, ssh_channelfind); - if (!c) - continue; /* nonexistent channel */ - if (c->closes == 0) { - ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE); - ssh2_pkt_adduint32(c->remoteid); - ssh2_pkt_send(); + if (!c || ((int)c->remoteid) == -1) { + bombout(("Received CHANNEL_CLOSE for %s channel %d\n", + c ? "half-open" : "nonexistent", i)); } /* Do pre-close processing on the channel. */ switch (c->type) { case CHAN_MAINSESSION: break; /* nothing to see here, move along */ case CHAN_X11: + if (c->u.x11.s != NULL) + x11_close(c->u.x11.s); + sshfwd_close(c); break; case CHAN_AGENT: + sshfwd_close(c); + break; + case CHAN_SOCKDATA: + if (c->u.pfd.s != NULL) + pfd_close(c->u.pfd.s); + sshfwd_close(c); break; } + if (c->closes == 0) { + ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE); + ssh2_pkt_adduint32(c->remoteid); + ssh2_pkt_send(); + } del234(ssh_channels, c); - sfree(c->v2.outbuffer); + bufchain_clear(&c->v.v2.outbuffer); sfree(c); /* * See if that was the last channel left open. */ if (count234(ssh_channels) == 0) { +#if 0 + /* + * We used to send SSH_MSG_DISCONNECT here, + * because I'd believed that _every_ conforming + * SSH2 connection had to end with a disconnect + * being sent by at least one side; apparently + * I was wrong and it's perfectly OK to + * unceremoniously slam the connection shut + * when you're done, and indeed OpenSSH feels + * this is more polite than sending a + * DISCONNECT. So now we don't. + */ logevent("All channels closed. Disconnecting"); ssh2_pkt_init(SSH2_MSG_DISCONNECT); ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION); ssh2_pkt_addstring("All open channels closed"); ssh2_pkt_addstring("en"); /* language tag */ ssh2_pkt_send(); +#endif ssh_state = SSH_STATE_CLOSED; crReturnV; } @@ -4099,16 +5447,139 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) c = find234(ssh_channels, &i, ssh_channelfind); if (!c) continue; /* nonexistent channel */ - c->v2.remwindow += ssh2_pkt_getuint32(); + c->v.v2.remwindow += ssh2_pkt_getuint32(); try_send = TRUE; + } else if (pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) { + unsigned i = ssh2_pkt_getuint32(); + struct ssh_channel *c; + c = find234(ssh_channels, &i, ssh_channelfind); + if (!c) + continue; /* nonexistent channel */ + if (c->type != CHAN_SOCKDATA_DORMANT) + continue; /* dunno why they're confirming this */ + c->remoteid = ssh2_pkt_getuint32(); + c->type = CHAN_SOCKDATA; + c->v.v2.remwindow = ssh2_pkt_getuint32(); + c->v.v2.remmaxpkt = ssh2_pkt_getuint32(); + if (c->u.pfd.s) + pfd_confirm(c->u.pfd.s); + if (c->closes) { + /* + * We have a pending close on this channel, + * which we decided on before the server acked + * the channel open. So now we know the + * remoteid, we can close it again. + */ + ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE); + ssh2_pkt_adduint32(c->remoteid); + ssh2_pkt_send(); + } + } else if (pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) { + unsigned i = ssh2_pkt_getuint32(); + struct ssh_channel *c; + c = find234(ssh_channels, &i, ssh_channelfind); + if (!c) + continue; /* nonexistent channel */ + if (c->type != CHAN_SOCKDATA_DORMANT) + continue; /* dunno why they're failing this */ + + logevent("Forwarded connection refused by server"); + + pfd_close(c->u.pfd.s); + + del234(ssh_channels, c); + sfree(c); + } else if (pktin.type == SSH2_MSG_CHANNEL_REQUEST) { + unsigned localid; + char *type; + int typelen, want_reply; + struct ssh_channel *c; + + localid = ssh2_pkt_getuint32(); + ssh2_pkt_getstring(&type, &typelen); + want_reply = ssh2_pkt_getbool(); + + /* + * First, check that the channel exists. Otherwise, + * we can instantly disconnect with a rude message. + */ + c = find234(ssh_channels, &localid, ssh_channelfind); + if (!c) { + char buf[80]; + sprintf(buf, "Received channel request for nonexistent" + " channel %d", localid); + logevent(buf); + ssh2_pkt_init(SSH2_MSG_DISCONNECT); + ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION); + ssh2_pkt_addstring(buf); + ssh2_pkt_addstring("en"); /* language tag */ + ssh2_pkt_send(); + connection_fatal("%s", buf); + ssh_state = SSH_STATE_CLOSED; + crReturnV; + } + + /* + * Having got the channel number, we now look at + * the request type string to see if it's something + * we recognise. + */ + if (typelen == 11 && !memcmp(type, "exit-status", 11) && + c == mainchan) { + /* We recognise "exit-status" on the primary channel. */ + char buf[100]; + ssh_exitcode = ssh2_pkt_getuint32(); + sprintf(buf, "Server sent command exit status %d", + ssh_exitcode); + logevent(buf); + if (want_reply) { + ssh2_pkt_init(SSH2_MSG_CHANNEL_SUCCESS); + ssh2_pkt_adduint32(c->remoteid); + ssh2_pkt_send(); + } + } else { + /* + * This is a channel request we don't know + * about, so we now either ignore the request + * or respond with CHANNEL_FAILURE, depending + * on want_reply. + */ + if (want_reply) { + ssh2_pkt_init(SSH2_MSG_CHANNEL_FAILURE); + ssh2_pkt_adduint32(c->remoteid); + ssh2_pkt_send(); + } + } + } else if (pktin.type == SSH2_MSG_GLOBAL_REQUEST) { + char *type; + int typelen, want_reply; + + ssh2_pkt_getstring(&type, &typelen); + want_reply = ssh2_pkt_getbool(); + + /* + * We currently don't support any global requests + * at all, so we either ignore the request or + * respond with REQUEST_FAILURE, depending on + * want_reply. + */ + if (want_reply) { + ssh2_pkt_init(SSH2_MSG_REQUEST_FAILURE); + ssh2_pkt_send(); + } } else if (pktin.type == SSH2_MSG_CHANNEL_OPEN) { char *type; int typelen; char *error = NULL; struct ssh_channel *c; + unsigned remid, winsize, pktsize; ssh2_pkt_getstring(&type, &typelen); c = smalloc(sizeof(struct ssh_channel)); + remid = ssh2_pkt_getuint32(); + winsize = ssh2_pkt_getuint32(); + pktsize = ssh2_pkt_getuint32(); + if (typelen == 3 && !memcmp(type, "x11", 3)) { if (!ssh_X11_fwd_enabled) error = "X11 forwarding is not enabled"; @@ -4118,6 +5589,32 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) } else { c->type = CHAN_X11; } + } else if (typelen == 15 && + !memcmp(type, "forwarded-tcpip", 15)) { + struct ssh_rportfwd pf, *realpf; + char *dummy; + int dummylen; + ssh2_pkt_getstring(&dummy, &dummylen);/* skip address */ + pf.sport = ssh2_pkt_getuint32(); + realpf = find234(ssh_rportfwds, &pf, NULL); + if (realpf == NULL) { + error = "Remote port is not recognised"; + } else { + char *e = pfd_newconnect(&c->u.pfd.s, realpf->dhost, + realpf->dport, c); + char buf[1024]; + sprintf(buf, "Received remote port open request for %s:%d", + realpf->dhost, realpf->dport); + logevent(buf); + if (e != NULL) { + sprintf(buf, "Port open failed: %s", e); + logevent(buf); + error = "Port open failed"; + } else { + logevent("Forwarded port opened successfully"); + c->type = CHAN_SOCKDATA; + } + } } else if (typelen == 22 && !memcmp(type, "auth-agent@openssh.com", 3)) { if (!ssh_agentfwd_enabled) @@ -4130,7 +5627,7 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) error = "Unsupported channel type requested"; } - c->remoteid = ssh2_pkt_getuint32(); + c->remoteid = remid; if (error) { ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_FAILURE); ssh2_pkt_adduint32(c->remoteid); @@ -4142,15 +5639,15 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) } else { c->localid = alloc_channel_id(); c->closes = 0; - c->v2.remwindow = ssh2_pkt_getuint32(); - c->v2.remmaxpkt = ssh2_pkt_getuint32(); - c->v2.outbuffer = NULL; - c->v2.outbuflen = c->v2.outbufsize = 0; + c->v.v2.locwindow = OUR_V2_WINSIZE; + c->v.v2.remwindow = winsize; + c->v.v2.remmaxpkt = pktsize; + bufchain_init(&c->v.v2.outbuffer); add234(ssh_channels, c); ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); ssh2_pkt_adduint32(c->remoteid); ssh2_pkt_adduint32(c->localid); - ssh2_pkt_adduint32(0x8000UL); /* our window size */ + ssh2_pkt_adduint32(c->v.v2.locwindow); ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */ ssh2_pkt_send(); } @@ -4171,8 +5668,27 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) /* * Try to send data on all channels if we can. */ - for (i = 0; NULL != (c = index234(ssh_channels, i)); i++) - ssh2_try_send(c); + for (i = 0; NULL != (c = index234(ssh_channels, i)); i++) { + int bufsize = ssh2_try_send(c); + if (bufsize == 0) { + switch (c->type) { + case CHAN_MAINSESSION: + /* stdin need not receive an unthrottle + * notification since it will be polled */ + break; + case CHAN_X11: + x11_unthrottle(c->u.x11.s); + break; + case CHAN_AGENT: + /* agent sockets are request/response and need no + * buffer management */ + break; + case CHAN_SOCKDATA: + pfd_unthrottle(c->u.pfd.s); + break; + } + } + } } } @@ -4194,7 +5710,8 @@ static void ssh2_protocol(unsigned char *in, int inlen, int ispkt) * * Returns an error message, or NULL on success. */ -static char *ssh_init(char *host, int port, char **realhost) +static char *ssh_init(void *frontend_handle, + char *host, int port, char **realhost, int nodelay) { char *p; @@ -4203,11 +5720,16 @@ static char *ssh_init(char *host, int port, char **realhost) return "Microsoft high encryption pack not installed!"; #endif + frontend = frontend_handle; + ssh_send_ok = 0; ssh_editing = 0; ssh_echoing = 0; + ssh1_throttle_count = 0; + ssh_overall_bufsize = 0; + ssh_fallback_cmd = 0; - p = connect_to_host(host, port, realhost); + p = connect_to_host(host, port, realhost, nodelay); if (p != NULL) return p; @@ -4217,12 +5739,44 @@ static char *ssh_init(char *host, int port, char **realhost) /* * Called to send data down the Telnet connection. */ -static void ssh_send(char *buf, int len) +static int ssh_send(char *buf, int len) { if (s == NULL || ssh_protocol == NULL) - return; + return 0; ssh_protocol(buf, len, 0); + + return ssh_sendbuffer(); +} + +/* + * Called to query the current amount of buffered stdin data. + */ +static int ssh_sendbuffer(void) +{ + int override_value; + + if (s == NULL || ssh_protocol == NULL) + return 0; + + /* + * If the SSH socket itself has backed up, add the total backup + * size on that to any individual buffer on the stdin channel. + */ + override_value = 0; + if (ssh_throttled_all) + override_value = ssh_overall_bufsize; + + if (ssh_version == 1) { + return override_value; + } else if (ssh_version == 2) { + if (!mainchan || mainchan->closes > 0) + return override_value; + else + return override_value + bufchain_size(&mainchan->v.v2.outbuffer); + } + + return 0; } /* @@ -4240,17 +5794,19 @@ static void ssh_size(void) break; case SSH_STATE_SESSION: if (!cfg.nopty) { + if (!term) + return; if (ssh_version == 1) { send_packet(SSH1_CMSG_WINDOW_SIZE, - PKT_INT, rows, PKT_INT, cols, + PKT_INT, term->rows, PKT_INT, term->cols, PKT_INT, 0, PKT_INT, 0, PKT_END); } else { ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST); ssh2_pkt_adduint32(mainchan->remoteid); ssh2_pkt_addstring("window-change"); ssh2_pkt_addbool(0); - ssh2_pkt_adduint32(cols); - ssh2_pkt_adduint32(rows); + ssh2_pkt_adduint32(term->cols); + ssh2_pkt_adduint32(term->rows); ssh2_pkt_adduint32(0); ssh2_pkt_adduint32(0); ssh2_pkt_send(); @@ -4289,7 +5845,8 @@ static void ssh_special(Telnet_Special code) if (ssh_state == SSH_STATE_CLOSED || ssh_state == SSH_STATE_PREPACKET) return; if (ssh_version == 1) { - send_packet(SSH1_MSG_IGNORE, PKT_STR, "", PKT_END); + if (!(ssh_remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) + send_packet(SSH1_MSG_IGNORE, PKT_STR, "", PKT_END); } else { ssh2_pkt_init(SSH2_MSG_IGNORE); ssh2_pkt_addstring_start(); @@ -4300,6 +5857,77 @@ static void ssh_special(Telnet_Special code) } } +void *new_sock_channel(Socket s) +{ + struct ssh_channel *c; + c = smalloc(sizeof(struct ssh_channel)); + + if (c) { + c->remoteid = -1; /* to be set when open confirmed */ + c->localid = alloc_channel_id(); + c->closes = 0; + c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */ + c->u.pfd.s = s; + bufchain_init(&c->v.v2.outbuffer); + add234(ssh_channels, c); + } + return c; +} + +/* + * This is called when stdout/stderr (the entity to which + * from_backend sends data) manages to clear some backlog. + */ +void ssh_unthrottle(int bufsize) +{ + if (ssh_version == 1) { + if (ssh1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) { + ssh1_stdout_throttling = 0; + ssh1_throttle(-1); + } + } else { + if (mainchan && mainchan->closes == 0) + ssh2_set_window(mainchan, OUR_V2_WINSIZE - bufsize); + } +} + +void ssh_send_port_open(void *channel, char *hostname, int port, char *org) +{ + struct ssh_channel *c = (struct ssh_channel *)channel; + char buf[1024]; + + sprintf(buf, "Opening forwarded connection to %.512s:%d", hostname, port); + logevent(buf); + + if (ssh_version == 1) { + send_packet(SSH1_MSG_PORT_OPEN, + PKT_INT, c->localid, + PKT_STR, hostname, + PKT_INT, port, + //PKT_STR, , + PKT_END); + } else { + ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN); + ssh2_pkt_addstring("direct-tcpip"); + ssh2_pkt_adduint32(c->localid); + c->v.v2.locwindow = OUR_V2_WINSIZE; + ssh2_pkt_adduint32(c->v.v2.locwindow);/* our window size */ + ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */ + ssh2_pkt_addstring(hostname); + ssh2_pkt_adduint32(port); + /* + * We make up values for the originator data; partly it's + * too much hassle to keep track, and partly I'm not + * convinced the server should be told details like that + * about my local network configuration. + */ + ssh2_pkt_addstring("client-side-connection"); + ssh2_pkt_adduint32(0); + ssh2_pkt_send(); + } +} + + static Socket ssh_socket(void) { return s; @@ -4319,13 +5947,21 @@ static int ssh_ldisc(int option) return FALSE; } +static int ssh_return_exitcode(void) +{ + return ssh_exitcode; +} + Backend ssh_backend = { ssh_init, ssh_send, + ssh_sendbuffer, ssh_size, ssh_special, ssh_socket, + ssh_return_exitcode, ssh_sendok, ssh_ldisc, + ssh_unthrottle, 22 };