X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=blobdiff_plain;f=ssh.c;h=c4c4fb9054e2aa7f2f3dbbbd0aa226e4cb7fa9d8;hb=f004bcca17a789356c32527a396b68b71a773db2;hp=893321e2b5a5f396004820f0f68aefcb460d0b31;hpb=4b2a2060bb829017b8098c0f3a2064d07145190e;p=PuTTY.git diff --git a/ssh.c b/ssh.c index 893321e2..c4c4fb90 100644 --- a/ssh.c +++ b/ssh.c @@ -32,6 +32,7 @@ typedef enum { SSH2_PKTCTX_NOKEX, SSH2_PKTCTX_DHGROUP, SSH2_PKTCTX_DHGEX, + SSH2_PKTCTX_ECDHKEX, SSH2_PKTCTX_RSAKEX } Pkt_KCtx; typedef enum { @@ -254,6 +255,8 @@ static char *ssh2_pkt_type(Pkt_KCtx pkt_kctx, Pkt_ACtx pkt_actx, int type) translatek(SSH2_MSG_KEXRSA_PUBKEY, SSH2_PKTCTX_RSAKEX); translatek(SSH2_MSG_KEXRSA_SECRET, SSH2_PKTCTX_RSAKEX); translatek(SSH2_MSG_KEXRSA_DONE, SSH2_PKTCTX_RSAKEX); + translatek(SSH2_MSG_KEX_ECDH_INIT, SSH2_PKTCTX_ECDHKEX); + translatek(SSH2_MSG_KEX_ECDH_REPLY, SSH2_PKTCTX_ECDHKEX); translate(SSH2_MSG_USERAUTH_REQUEST); translate(SSH2_MSG_USERAUTH_FAILURE); translate(SSH2_MSG_USERAUTH_SUCCESS); @@ -397,7 +400,10 @@ static void ssh_channel_destroy(struct ssh_channel *c); #define OUR_V2_MAXPKT 0x4000UL #define OUR_V2_PACKETLIMIT 0x9000UL -const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss }; +const static struct ssh_signkey *hostkey_algs[] = { + &ssh_ecdsa_nistp256, &ssh_ecdsa_nistp384, &ssh_ecdsa_nistp521, + &ssh_rsa, &ssh_dss +}; const static struct ssh_mac *macs[] = { &ssh_hmac_sha256, &ssh_hmac_sha1, &ssh_hmac_sha1_96, &ssh_hmac_md5 @@ -2960,11 +2966,13 @@ static int do_ssh_init(Ssh ssh, unsigned char c) s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0; if (conf_get_int(ssh->conf, CONF_sshprot) == 0 && !s->proto1) { - bombout(("SSH protocol version 1 required by user but not provided by server")); + bombout(("SSH protocol version 1 required by configuration but " + "not provided by server")); crStop(0); } if (conf_get_int(ssh->conf, CONF_sshprot) == 3 && !s->proto2) { - bombout(("SSH protocol version 2 required by user but not provided by server")); + bombout(("SSH protocol version 2 required by configuration but " + "not provided by server")); crStop(0); } @@ -3285,6 +3293,14 @@ static int ssh_do_close(Ssh ssh, int notify_exit) ssh->portfwds = NULL; } + /* + * Also stop attempting to connection-share. + */ + if (ssh->connshare) { + sharestate_free(ssh->connshare); + ssh->connshare = NULL; + } + return ret; } @@ -3677,6 +3693,59 @@ static void ssh_disconnect(Ssh ssh, char *client_reason, char *wire_reason, sfree(error); } +int verify_ssh_manual_host_key(Ssh ssh, const char *fingerprint, + const struct ssh_signkey *ssh2keytype, + void *ssh2keydata) +{ + if (!conf_get_str_nthstrkey(ssh->conf, CONF_ssh_manual_hostkeys, 0)) { + return -1; /* no manual keys configured */ + } + + if (fingerprint) { + /* + * The fingerprint string we've been given will have things + * like 'ssh-rsa 2048' at the front of it. Strip those off and + * narrow down to just the colon-separated hex block at the + * end of the string. + */ + const char *p = strrchr(fingerprint, ' '); + fingerprint = p ? p+1 : fingerprint; + /* Quick sanity checks, including making sure it's in lowercase */ + assert(strlen(fingerprint) == 16*3 - 1); + assert(fingerprint[2] == ':'); + assert(fingerprint[strspn(fingerprint, "0123456789abcdef:")] == 0); + + if (conf_get_str_str_opt(ssh->conf, CONF_ssh_manual_hostkeys, + fingerprint)) + return 1; /* success */ + } + + if (ssh2keydata) { + /* + * Construct the base64-encoded public key blob and see if + * that's listed. + */ + unsigned char *binblob; + char *base64blob; + int binlen, atoms, i; + binblob = ssh2keytype->public_blob(ssh2keydata, &binlen); + atoms = (binlen + 2) / 3; + base64blob = snewn(atoms * 4 + 1, char); + for (i = 0; i < atoms; i++) + base64_encode_atom(binblob + 3*i, binlen - 3*i, base64blob + 4*i); + base64blob[atoms * 4] = '\0'; + sfree(binblob); + if (conf_get_str_str_opt(ssh->conf, CONF_ssh_manual_hostkeys, + base64blob)) { + sfree(base64blob); + return 1; /* success */ + } + sfree(base64blob); + } + + return 0; +} + /* * Handle the key exchange and user authentication phases. */ @@ -3800,29 +3869,39 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, rsastr_fmt(keystr, &s->hostkey); rsa_fingerprint(fingerprint, sizeof(fingerprint), &s->hostkey); - ssh_set_frozen(ssh, 1); - s->dlgret = verify_ssh_host_key(ssh->frontend, - ssh->savedhost, ssh->savedport, - "rsa", keystr, fingerprint, - ssh_dialog_callback, ssh); - sfree(keystr); - if (s->dlgret < 0) { - do { - crReturn(0); - if (pktin) { - bombout(("Unexpected data from server while waiting" - " for user host key response")); - crStop(0); - } - } while (pktin || inlen > 0); - s->dlgret = ssh->user_response; - } - ssh_set_frozen(ssh, 0); + /* First check against manually configured host keys. */ + s->dlgret = verify_ssh_manual_host_key(ssh, fingerprint, NULL, NULL); + if (s->dlgret == 0) { /* did not match */ + bombout(("Host key did not appear in manually configured list")); + sfree(keystr); + crStop(0); + } else if (s->dlgret < 0) { /* none configured; use standard handling */ + ssh_set_frozen(ssh, 1); + s->dlgret = verify_ssh_host_key(ssh->frontend, + ssh->savedhost, ssh->savedport, + "rsa", keystr, fingerprint, + ssh_dialog_callback, ssh); + sfree(keystr); + if (s->dlgret < 0) { + do { + crReturn(0); + if (pktin) { + bombout(("Unexpected data from server while waiting" + " for user host key response")); + crStop(0); + } + } while (pktin || inlen > 0); + s->dlgret = ssh->user_response; + } + ssh_set_frozen(ssh, 0); - if (s->dlgret == 0) { - ssh_disconnect(ssh, "User aborted at host key verification", - NULL, 0, TRUE); - crStop(0); + if (s->dlgret == 0) { + ssh_disconnect(ssh, "User aborted at host key verification", + NULL, 0, TRUE); + crStop(0); + } + } else { + sfree(keystr); } } @@ -5753,7 +5832,7 @@ static void do_ssh1_connection(Ssh ssh, unsigned char *in, int inlen, ssh_special(ssh, TS_EOF); if (ssh->ldisc) - ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */ + ldisc_echoedit_update(ssh->ldisc); /* cause ldisc to notice changes */ ssh->send_ok = 1; ssh->channels = newtree234(ssh_channelcmp); while (1) { @@ -5860,7 +5939,8 @@ static void ssh1_protocol(Ssh ssh, void *vin, int inlen, /* * Utility routine for decoding comma-separated strings in KEXINIT. */ -static int in_commasep_string(char *needle, char *haystack, int haylen) +static int in_commasep_string(char const *needle, char const *haystack, + int haylen) { int needlen; if (!needle || !haystack) /* protect against null pointers */ @@ -5891,7 +5971,8 @@ static int in_commasep_string(char *needle, char *haystack, int haylen) /* * Similar routine for checking whether we have the first string in a list. */ -static int first_in_commasep_string(char *needle, char *haystack, int haylen) +static int first_in_commasep_string(char const *needle, char const *haystack, + int haylen) { int needlen; if (!needle || !haystack) /* protect against null pointers */ @@ -5909,6 +5990,19 @@ static int first_in_commasep_string(char *needle, char *haystack, int haylen) return 0; } +/* + * Add a value to the comma-separated string at the end of the packet. + * If the value is already in the string, don't bother adding it again. + */ +static void ssh2_pkt_addstring_commasep(struct Packet *pkt, const char *data) +{ + if (in_commasep_string(data, (char *)pkt->data + pkt->savedpos, + pkt->length - pkt->savedpos)) return; + if (pkt->length - pkt->savedpos > 0) + ssh_pkt_addstring_str(pkt, ","); + ssh_pkt_addstring_str(pkt, data); +} + /* * SSH-2 key creation method. @@ -5964,6 +6058,7 @@ static void do_ssh2_transport(Ssh ssh, void *vin, int inlen, int hostkeylen, siglen, rsakeylen; void *hkey; /* actual host key */ void *rsakey; /* for RSA kex */ + void *eckey; /* for ECDH kex */ unsigned char exchange_hash[SSH2_KEX_MAX_HASH_LEN]; int n_preferred_kex; const struct ssh_kexes *preferred_kex[KEX_MAX]; @@ -6003,7 +6098,7 @@ static void do_ssh2_transport(Ssh ssh, void *vin, int inlen, begin_key_exchange: ssh->pkt_kctx = SSH2_PKTCTX_NOKEX; { - int i, j, k, commalist_started; + int i, j, k; /* * Set up the preferred key exchange. (NULL => warn below here) @@ -6027,6 +6122,10 @@ static void do_ssh2_transport(Ssh ssh, void *vin, int inlen, s->preferred_kex[s->n_preferred_kex++] = &ssh_rsa_kex; break; + case KEX_ECDH: + s->preferred_kex[s->n_preferred_kex++] = + &ssh_ecdh_kex; + break; case KEX_WARN: /* Flag for later. Don't bother if it's the last in * the list. */ @@ -6097,16 +6196,11 @@ static void do_ssh2_transport(Ssh ssh, void *vin, int inlen, ssh2_pkt_addbyte(s->pktout, (unsigned char) random_byte()); /* List key exchange algorithms. */ ssh2_pkt_addstring_start(s->pktout); - commalist_started = 0; for (i = 0; i < s->n_preferred_kex; i++) { const struct ssh_kexes *k = s->preferred_kex[i]; if (!k) continue; /* warning flag */ - for (j = 0; j < k->nkexes; j++) { - if (commalist_started) - ssh2_pkt_addstring_str(s->pktout, ","); - ssh2_pkt_addstring_str(s->pktout, k->list[j]->name); - commalist_started = 1; - } + for (j = 0; j < k->nkexes; j++) + ssh2_pkt_addstring_commasep(s->pktout, k->list[j]->name); } /* List server host key algorithms. */ if (!s->got_session_id) { @@ -6115,11 +6209,8 @@ static void do_ssh2_transport(Ssh ssh, void *vin, int inlen, * we're prepared to cope with. */ ssh2_pkt_addstring_start(s->pktout); - for (i = 0; i < lenof(hostkey_algs); i++) { - ssh2_pkt_addstring_str(s->pktout, hostkey_algs[i]->name); - if (i < lenof(hostkey_algs) - 1) - ssh2_pkt_addstring_str(s->pktout, ","); - } + for (i = 0; i < lenof(hostkey_algs); i++) + ssh2_pkt_addstring_commasep(s->pktout, hostkey_algs[i]->name); } else { /* * In subsequent key exchanges, we list only the kex @@ -6134,26 +6225,18 @@ static void do_ssh2_transport(Ssh ssh, void *vin, int inlen, /* List encryption algorithms (client->server then server->client). */ for (k = 0; k < 2; k++) { ssh2_pkt_addstring_start(s->pktout); - commalist_started = 0; for (i = 0; i < s->n_preferred_ciphers; i++) { const struct ssh2_ciphers *c = s->preferred_ciphers[i]; if (!c) continue; /* warning flag */ - for (j = 0; j < c->nciphers; j++) { - if (commalist_started) - ssh2_pkt_addstring_str(s->pktout, ","); - ssh2_pkt_addstring_str(s->pktout, c->list[j]->name); - commalist_started = 1; - } + for (j = 0; j < c->nciphers; j++) + ssh2_pkt_addstring_commasep(s->pktout, c->list[j]->name); } } /* List MAC algorithms (client->server then server->client). */ for (j = 0; j < 2; j++) { ssh2_pkt_addstring_start(s->pktout); - for (i = 0; i < s->nmacs; i++) { - ssh2_pkt_addstring_str(s->pktout, s->maclist[i]->name); - if (i < s->nmacs - 1) - ssh2_pkt_addstring_str(s->pktout, ","); - } + for (i = 0; i < s->nmacs; i++) + ssh2_pkt_addstring_commasep(s->pktout, s->maclist[i]->name); } /* List client->server compression algorithms, * then server->client compression algorithms. (We use the @@ -6162,25 +6245,18 @@ static void do_ssh2_transport(Ssh ssh, void *vin, int inlen, ssh2_pkt_addstring_start(s->pktout); assert(lenof(compressions) > 1); /* Prefer non-delayed versions */ - ssh2_pkt_addstring_str(s->pktout, s->preferred_comp->name); + ssh2_pkt_addstring_commasep(s->pktout, s->preferred_comp->name); /* We don't even list delayed versions of algorithms until * they're allowed to be used, to avoid a race. See the end of * this function. */ - if (s->userauth_succeeded && s->preferred_comp->delayed_name) { - ssh2_pkt_addstring_str(s->pktout, ","); - ssh2_pkt_addstring_str(s->pktout, - s->preferred_comp->delayed_name); - } + if (s->userauth_succeeded && s->preferred_comp->delayed_name) + ssh2_pkt_addstring_commasep(s->pktout, + s->preferred_comp->delayed_name); for (i = 0; i < lenof(compressions); i++) { const struct ssh_compress *c = compressions[i]; - if (c != s->preferred_comp) { - ssh2_pkt_addstring_str(s->pktout, ","); - ssh2_pkt_addstring_str(s->pktout, c->name); - if (s->userauth_succeeded && c->delayed_name) { - ssh2_pkt_addstring_str(s->pktout, ","); - ssh2_pkt_addstring_str(s->pktout, c->delayed_name); - } - } + ssh2_pkt_addstring_commasep(s->pktout, c->name); + if (s->userauth_succeeded && c->delayed_name) + ssh2_pkt_addstring_commasep(s->pktout, c->delayed_name); } } /* List client->server languages. Empty list. */ @@ -6593,6 +6669,83 @@ static void do_ssh2_transport(Ssh ssh, void *vin, int inlen, freebn(s->g); freebn(s->p); } + } else if (ssh->kex->main_type == KEXTYPE_ECDH) { + + logeventf(ssh, "Doing ECDH key exchange with hash %s", + ssh->kex->hash->text_name); + ssh->pkt_kctx = SSH2_PKTCTX_ECDHKEX; + + s->eckey = NULL; + if (!strcmp(ssh->kex->name, "ecdh-sha2-nistp256")) { + s->eckey = ssh_ecdhkex_newkey(ec_p256()); + } else if (!strcmp(ssh->kex->name, "ecdh-sha2-nistp384")) { + s->eckey = ssh_ecdhkex_newkey(ec_p384()); + } else if (!strcmp(ssh->kex->name, "ecdh-sha2-nistp521")) { + s->eckey = ssh_ecdhkex_newkey(ec_p521()); + } + if (!s->eckey) { + bombout(("Unable to generate key for ECDH")); + crStopV; + } + + { + char *publicPoint; + int publicPointLength; + publicPoint = ssh_ecdhkex_getpublic(s->eckey, &publicPointLength); + if (!publicPoint) { + ssh_ecdhkex_freekey(s->eckey); + bombout(("Unable to encode public key for ECDH")); + crStopV; + } + s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_ECDH_INIT); + ssh2_pkt_addstring_start(s->pktout); + ssh2_pkt_addstring_data(s->pktout, publicPoint, publicPointLength); + sfree(publicPoint); + } + + ssh2_pkt_send_noqueue(ssh, s->pktout); + + crWaitUntilV(pktin); + if (pktin->type != SSH2_MSG_KEX_ECDH_REPLY) { + ssh_ecdhkex_freekey(s->eckey); + bombout(("expected ECDH reply packet from server")); + crStopV; + } + + ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen); + hash_string(ssh->kex->hash, ssh->exhash, s->hostkeydata, s->hostkeylen); + s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen); + + { + char *publicPoint; + int publicPointLength; + publicPoint = ssh_ecdhkex_getpublic(s->eckey, &publicPointLength); + if (!publicPoint) { + ssh_ecdhkex_freekey(s->eckey); + bombout(("Unable to encode public key for ECDH hash")); + crStopV; + } + hash_string(ssh->kex->hash, ssh->exhash, + publicPoint, publicPointLength); + sfree(publicPoint); + } + + { + char *keydata; + int keylen; + ssh_pkt_getstring(pktin, &keydata, &keylen); + hash_string(ssh->kex->hash, ssh->exhash, keydata, keylen); + s->K = ssh_ecdhkex_getkey(s->eckey, keydata, keylen); + if (!s->K) { + ssh_ecdhkex_freekey(s->eckey); + bombout(("point received in ECDH was not valid")); + crStopV; + } + } + + ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen); + + ssh_ecdhkex_freekey(s->eckey); } else { logeventf(ssh, "Doing RSA key exchange with hash %s", ssh->kex->hash->text_name); @@ -6721,31 +6874,39 @@ static void do_ssh2_transport(Ssh ssh, void *vin, int inlen, * checked the signature of the exchange hash.) */ s->fingerprint = ssh->hostkey->fingerprint(s->hkey); - ssh_set_frozen(ssh, 1); - s->dlgret = verify_ssh_host_key(ssh->frontend, - ssh->savedhost, ssh->savedport, - ssh->hostkey->keytype, s->keystr, - s->fingerprint, - ssh_dialog_callback, ssh); - if (s->dlgret < 0) { - do { - crReturnV; - if (pktin) { - bombout(("Unexpected data from server while waiting" - " for user host key response")); - crStopV; - } - } while (pktin || inlen > 0); - s->dlgret = ssh->user_response; - } - ssh_set_frozen(ssh, 0); - if (s->dlgret == 0) { - ssh_disconnect(ssh, "User aborted at host key verification", NULL, - 0, TRUE); - crStopV; - } logevent("Host key fingerprint is:"); logevent(s->fingerprint); + /* First check against manually configured host keys. */ + s->dlgret = verify_ssh_manual_host_key(ssh, s->fingerprint, + ssh->hostkey, s->hkey); + if (s->dlgret == 0) { /* did not match */ + bombout(("Host key did not appear in manually configured list")); + crStopV; + } else if (s->dlgret < 0) { /* none configured; use standard handling */ + ssh_set_frozen(ssh, 1); + s->dlgret = verify_ssh_host_key(ssh->frontend, + ssh->savedhost, ssh->savedport, + ssh->hostkey->keytype, s->keystr, + s->fingerprint, + ssh_dialog_callback, ssh); + if (s->dlgret < 0) { + do { + crReturnV; + if (pktin) { + bombout(("Unexpected data from server while waiting" + " for user host key response")); + crStopV; + } + } while (pktin || inlen > 0); + s->dlgret = ssh->user_response; + } + ssh_set_frozen(ssh, 0); + if (s->dlgret == 0) { + ssh_disconnect(ssh, "Aborted at host key verification", NULL, + 0, TRUE); + crStopV; + } + } sfree(s->fingerprint); /* * Save this host key, to check against the one presented in @@ -10165,7 +10326,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, * Transfer data! */ if (ssh->ldisc) - ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */ + ldisc_echoedit_update(ssh->ldisc); /* cause ldisc to notice changes */ if (ssh->mainchan) ssh->send_ok = 1; while (1) { @@ -10517,6 +10678,8 @@ static const char *ssh_init(void *frontend_handle, void **backend_handle, ssh->sent_console_eof = FALSE; ssh->got_pty = FALSE; ssh->bare_connection = FALSE; + ssh->X11_fwd_enabled = FALSE; + ssh->connshare = NULL; ssh->attempting_connshare = FALSE; *backend_handle = ssh; @@ -10557,11 +10720,13 @@ static const char *ssh_init(void *frontend_handle, void **backend_handle, ssh->gsslibs = NULL; #endif + random_ref(); /* do this now - may be needed by sharing setup code */ + p = connect_to_host(ssh, host, port, realhost, nodelay, keepalive); - if (p != NULL) + if (p != NULL) { + random_unref(); return p; - - random_ref(); + } return NULL; } @@ -11169,13 +11334,19 @@ static int ssh_return_exitcode(void *handle) } /* - * cfg_info for SSH is the currently running version of the - * protocol. (1 for 1; 2 for 2; 0 for not-decided-yet.) + * cfg_info for SSH is the protocol running in this session. + * (1 or 2 for the full SSH-1 or SSH-2 protocol; -1 for the bare + * SSH-2 connection protocol, i.e. a downstream; 0 for not-decided-yet.) */ static int ssh_cfg_info(void *handle) { Ssh ssh = (Ssh) handle; - return ssh->version; + if (ssh->version == 0) + return 0; /* don't know yet */ + else if (ssh->bare_connection) + return -1; + else + return ssh->version; } /*