X-Git-Url: http://andersk.mit.edu/gitweb/gssapi-openssh.git/blobdiff_plain/5598e598f2b9714c3b08a211d401c780e74dabe2..b5afdff53b51d529e596da3b4c2aa5ee14cc8b08:/openssh/sshconnect2.c diff --git a/openssh/sshconnect2.c b/openssh/sshconnect2.c index d97aed4..4744e37 100644 --- a/openssh/sshconnect2.c +++ b/openssh/sshconnect2.c @@ -1,5 +1,7 @@ +/* $OpenBSD: sshconnect2.c,v 1.171 2009/03/05 07:18:19 djm Exp $ */ /* * Copyright (c) 2000 Markus Friedl. All rights reserved. + * Copyright (c) 2008 Damien Miller. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions @@ -23,36 +25,51 @@ */ #include "includes.h" -RCSID("$OpenBSD: sshconnect2.c,v 1.85 2001/11/07 16:03:17 markus Exp $"); -#include -#include -#include -#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H) +#include +#endif + +#include "openbsd-compat/sys-queue.h" +#include "xmalloc.h" #include "ssh.h" #include "ssh2.h" -#include "xmalloc.h" -#include "rsa.h" #include "buffer.h" #include "packet.h" -#include "uidswap.h" #include "compat.h" -#include "bufaux.h" #include "cipher.h" +#include "key.h" #include "kex.h" #include "myproposal.h" -#include "key.h" #include "sshconnect.h" #include "authfile.h" #include "dh.h" #include "authfd.h" #include "log.h" #include "readconf.h" -#include "readpass.h" +#include "misc.h" #include "match.h" #include "dispatch.h" #include "canohost.h" +#include "msg.h" +#include "pathnames.h" +#include "uidswap.h" +#include "schnorr.h" +#include "jpake.h" #ifdef GSSAPI #include "ssh-gss.h" @@ -62,13 +79,29 @@ RCSID("$OpenBSD: sshconnect2.c,v 1.85 2001/11/07 16:03:17 markus Exp $"); extern char *client_version_string; extern char *server_version_string; extern Options options; +extern Kex *xxx_kex; + +/* tty_flag is set in ssh.c. use this in ssh_userauth2 */ +/* if it is set then prevent the switch to the null cipher */ + +extern int tty_flag; + +/* tty_flag is set in ssh.c. use this in ssh_userauth2 */ +/* if it is set then prevent the switch to the null cipher */ + +extern int tty_flag; + +/* tty_flag is set in ssh.c. use this in ssh_userauth2 */ +/* if it is set then prevent the switch to the null cipher */ + +extern int tty_flag; /* * SSH2 key exchange */ u_char *session_id2 = NULL; -int session_id2_len = 0; +u_int session_id2_len = 0; char *xxx_host; struct sockaddr *xxx_hostaddr; @@ -88,35 +121,36 @@ ssh_kex2(char *host, struct sockaddr *hostaddr) { Kex *kex; +#ifdef GSSAPI + char *orig = NULL, *gss = NULL; + char *gss_host = NULL; +#endif + xxx_host = host; xxx_hostaddr = hostaddr; #ifdef GSSAPI - /* This is a bit of a nasty kludge. This adds the GSSAPI included - * key exchange methods to the top of the list, allowing the GSSAPI - * code to decide whether each one should be included or not. - */ - { - char *orig, *gss; - int len; + if (options.gss_keyex) { + /* Add the GSSAPI mechanisms currently supported on this + * client to the key exchange algorithm proposal */ orig = myproposal[PROPOSAL_KEX_ALGS]; - gss = ssh_gssapi_mechanisms(0,host); + + if (options.gss_trust_dns) + gss_host = (char *)get_canonical_hostname(1); + else + gss_host = host; + + gss = ssh_gssapi_client_mechanisms(gss_host, options.gss_client_identity); if (gss) { - len = strlen(orig)+strlen(gss)+2; - myproposal[PROPOSAL_KEX_ALGS]=xmalloc(len); - snprintf(myproposal[PROPOSAL_KEX_ALGS],len,"%s,%s",gss,orig); - /* If we've got GSSAPI algorithms, then we also support the - * 'null' hostkey, as a last resort */ - orig=myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]; - len = strlen(orig)+sizeof(",null"); - myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]=xmalloc(len); - snprintf(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS],len,"%s,null",orig); + debug("Offering GSSAPI proposal: %s", gss); + xasprintf(&myproposal[PROPOSAL_KEX_ALGS], + "%s,%s", gss, orig); } } #endif if (options.ciphers == (char *)-1) { - log("No valid ciphers for protocol version 2 given, using defaults."); + logit("No valid ciphers for protocol version 2 given, using defaults."); options.ciphers = NULL; } if (options.ciphers != NULL) { @@ -129,28 +163,57 @@ ssh_kex2(char *host, struct sockaddr *hostaddr) compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); if (options.compression) { myproposal[PROPOSAL_COMP_ALGS_CTOS] = - myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib"; + myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none"; } else { myproposal[PROPOSAL_COMP_ALGS_CTOS] = - myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; + myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib"; } if (options.macs != NULL) { myproposal[PROPOSAL_MAC_ALGS_CTOS] = myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; } if (options.hostkeyalgorithms != NULL) - myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = + myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = options.hostkeyalgorithms; +#ifdef GSSAPI + /* If we've got GSSAPI algorithms, then we also support the + * 'null' hostkey, as a last resort */ + if (options.gss_keyex && gss) { + orig = myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]; + xasprintf(&myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS], + "%s,null", orig); + xfree(gss); + } +#endif + + if (options.rekey_limit) + packet_set_rekey_limit((u_int32_t)options.rekey_limit); + /* start key exchange */ kex = kex_setup(myproposal); + kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; + kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; + kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; + kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; +#ifdef GSSAPI + if (options.gss_keyex) { + kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_client; + kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_client; + kex->kex[KEX_GSS_GEX_SHA1] = kexgss_client; + } +#endif kex->client_version_string=client_version_string; kex->server_version_string=server_version_string; kex->verify_host_key=&verify_host_key_callback; - kex->host=host; #ifdef GSSAPI - kex->options.gss_deleg_creds=options.gss_deleg_creds; + if (options.gss_keyex) { + kex->gss_deleg_creds = options.gss_deleg_creds; + kex->gss_trust_dns = options.gss_trust_dns; + kex->gss_client = options.gss_client_identity; + kex->gss_host = gss_host; + } #endif xxx_kex = kex; @@ -167,7 +230,6 @@ ssh_kex2(char *host, struct sockaddr *hostaddr) packet_send(); packet_write_wait(); #endif - debug("done: ssh_kex2."); } /* @@ -176,10 +238,18 @@ ssh_kex2(char *host, struct sockaddr *hostaddr) typedef struct Authctxt Authctxt; typedef struct Authmethod Authmethod; - -typedef int sign_cb_fn( - Authctxt *authctxt, Key *key, - u_char **sigp, int *lenp, u_char *data, int datalen); +typedef struct identity Identity; +typedef struct idlist Idlist; + +struct identity { + TAILQ_ENTRY(identity) next; + AuthenticationConnection *ac; /* set if agent supports key */ + Key *key; /* public/private key */ + char *filename; /* comment for agent-only keys */ + int tried; + int isprivate; /* key points to the private key */ +}; +TAILQ_HEAD(idlist, identity); struct Authctxt { const char *server_user; @@ -190,13 +260,10 @@ struct Authctxt { int success; char *authlist; /* pubkey */ - Key *last_key; - sign_cb_fn *last_key_sign; - int last_key_hint; + Idlist keys; AuthenticationConnection *agent; /* hostbased */ - Key **keys; - int nkeys; + Sensitive *sensitive; /* kbd-interactive */ int info_req_seen; /* generic */ @@ -205,37 +272,50 @@ struct Authctxt { struct Authmethod { char *name; /* string to compare against server's list */ int (*userauth)(Authctxt *authctxt); + void (*cleanup)(Authctxt *authctxt); int *enabled; /* flag in option struct that enables method */ int *batch_flag; /* flag in option struct that disables method */ }; -void input_userauth_success(int type, int plen, void *ctxt); -void input_userauth_failure(int type, int plen, void *ctxt); -void input_userauth_banner(int type, int plen, void *ctxt); -void input_userauth_error(int type, int plen, void *ctxt); -void input_userauth_info_req(int type, int plen, void *ctxt); -void input_userauth_pk_ok(int type, int plen, void *ctxt); - -int userauth_none(Authctxt *authctxt); -int userauth_pubkey(Authctxt *authctxt); -int userauth_passwd(Authctxt *authctxt); -int userauth_kbdint(Authctxt *authctxt); -int userauth_hostbased(Authctxt *authctxt); +void input_userauth_success(int, u_int32_t, void *); +void input_userauth_failure(int, u_int32_t, void *); +void input_userauth_banner(int, u_int32_t, void *); +void input_userauth_error(int, u_int32_t, void *); +void input_userauth_info_req(int, u_int32_t, void *); +void input_userauth_pk_ok(int, u_int32_t, void *); +void input_userauth_passwd_changereq(int, u_int32_t, void *); +void input_userauth_jpake_server_step1(int, u_int32_t, void *); +void input_userauth_jpake_server_step2(int, u_int32_t, void *); +void input_userauth_jpake_server_confirm(int, u_int32_t, void *); + +int userauth_none(Authctxt *); +int userauth_pubkey(Authctxt *); +int userauth_passwd(Authctxt *); +int userauth_kbdint(Authctxt *); +int userauth_hostbased(Authctxt *); +int userauth_jpake(Authctxt *); + +void userauth_jpake_cleanup(Authctxt *); #ifdef GSSAPI -int userauth_external(Authctxt *authctxt); -int userauth_gssapi(Authctxt *authctxt); -void input_gssapi_response(int type, int plen, void *ctxt); -void input_gssapi_token(int type, int plen, void *ctxt); -void input_gssapi_hash(int type, int plen, void *ctxt); - -int gss_host_key_ok=0; +int userauth_external(Authctxt *authctxt); +int userauth_gssapi(Authctxt *authctxt); +int userauth_gssapi_with_mic(Authctxt *authctxt); +int userauth_gssapi_without_mic(Authctxt *authctxt); +void input_gssapi_response(int type, u_int32_t, void *); +void input_gssapi_token(int type, u_int32_t, void *); +void input_gssapi_hash(int type, u_int32_t, void *); +void input_gssapi_error(int, u_int32_t, void *); +void input_gssapi_errtok(int, u_int32_t, void *); +int userauth_gsskeyex(Authctxt *authctxt); #endif -void userauth(Authctxt *authctxt, char *authlist); +void userauth(Authctxt *, char *); -static int sign_and_send_pubkey(Authctxt *, Key *, sign_cb_fn *); -static void clear_auth_state(Authctxt *); +static int sign_and_send_pubkey(Authctxt *, Identity *); +static void pubkey_prepare(Authctxt *); +static void pubkey_cleanup(Authctxt *); +static Key *load_identity_file(char *); static Authmethod *authmethod_get(char *authlist); static Authmethod *authmethod_lookup(const char *name); @@ -243,74 +323,96 @@ static char *authmethods_get(void); Authmethod authmethods[] = { #ifdef GSSAPI + {"gssapi-keyex", + userauth_gsskeyex, + NULL, + &options.gss_authentication, + NULL}, {"external-keyx", userauth_external, + NULL, + &options.gss_authentication, + NULL}, + {"gssapi-with-mic", + userauth_gssapi, + NULL, &options.gss_authentication, NULL}, {"gssapi", userauth_gssapi, + NULL, &options.gss_authentication, NULL}, #endif {"hostbased", userauth_hostbased, + NULL, &options.hostbased_authentication, NULL}, {"publickey", userauth_pubkey, + NULL, &options.pubkey_authentication, NULL}, +#ifdef JPAKE + {"jpake-01@openssh.com", + userauth_jpake, + userauth_jpake_cleanup, + &options.zero_knowledge_password_authentication, + &options.batch_mode}, +#endif {"keyboard-interactive", userauth_kbdint, + NULL, &options.kbd_interactive_authentication, &options.batch_mode}, {"password", userauth_passwd, + NULL, &options.password_authentication, &options.batch_mode}, {"none", userauth_none, NULL, + NULL, NULL}, - {NULL, NULL, NULL, NULL} + {NULL, NULL, NULL, NULL, NULL} }; void ssh_userauth2(const char *local_user, const char *server_user, char *host, - Key **keys, int nkeys) + Sensitive *sensitive) { Authctxt authctxt; int type; - int plen; if (options.challenge_response_authentication) options.kbd_interactive_authentication = 1; - debug("send SSH2_MSG_SERVICE_REQUEST"); packet_start(SSH2_MSG_SERVICE_REQUEST); packet_put_cstring("ssh-userauth"); packet_send(); + debug("SSH2_MSG_SERVICE_REQUEST sent"); packet_write_wait(); - type = packet_read(&plen); - if (type != SSH2_MSG_SERVICE_ACCEPT) { - fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type); - } + type = packet_read(); + if (type != SSH2_MSG_SERVICE_ACCEPT) + fatal("Server denied authentication request: %d", type); if (packet_remaining() > 0) { - char *reply = packet_get_string(&plen); - debug("service_accept: %s", reply); + char *reply = packet_get_string(NULL); + debug2("service_accept: %s", reply); xfree(reply); } else { - debug("buggy server: service_accept w/o service"); + debug2("buggy server: service_accept w/o service"); } - packet_done(); - debug("got SSH2_MSG_SERVICE_ACCEPT"); + packet_check_eom(); + debug("SSH2_MSG_SERVICE_ACCEPT received"); if (options.preferred_authentications == NULL) options.preferred_authentications = authmethods_get(); /* setup authentication context */ memset(&authctxt, 0, sizeof(authctxt)); - authctxt.agent = ssh_get_authentication_connection(); + pubkey_prepare(&authctxt); authctxt.server_user = server_user; authctxt.local_user = local_user; authctxt.host = host; @@ -319,8 +421,7 @@ ssh_userauth2(const char *local_user, const char *server_user, char *host, authctxt.method = authmethod_lookup("none"); authctxt.authlist = NULL; authctxt.methoddata = NULL; - authctxt.keys = keys; - authctxt.nkeys = nkeys; + authctxt.sensitive = sensitive; authctxt.info_req_seen = 0; if (authctxt.method == NULL) fatal("ssh_userauth2: internal error: cannot send userauth none request"); @@ -334,19 +435,44 @@ ssh_userauth2(const char *local_user, const char *server_user, char *host, dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ - if (authctxt.agent != NULL) - ssh_close_authentication_connection(authctxt.agent); + pubkey_cleanup(&authctxt); + dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); - debug("ssh-userauth2 successful: method %s", authctxt.method->name); + /* if the user wants to use the none cipher do it */ + /* post authentication and only if the right conditions are met */ + /* both of the NONE commands must be true and there must be no */ + /* tty allocated */ + if ((options.none_switch == 1) && (options.none_enabled == 1)) + { + if (!tty_flag) /* no null on tty sessions */ + { + debug("Requesting none rekeying..."); + myproposal[PROPOSAL_ENC_ALGS_STOC] = "none"; + myproposal[PROPOSAL_ENC_ALGS_CTOS] = "none"; + kex_prop2buf(&xxx_kex->my,myproposal); + packet_request_rekeying(); + fprintf(stderr, "WARNING: ENABLED NONE CIPHER\n"); + } + else + { + /* requested NONE cipher when in a tty */ + debug("Cannot switch to NONE cipher with tty allocated"); + fprintf(stderr, "NONE cipher switch disabled when a TTY is allocated\n"); + } + } + debug("Authentication succeeded (%s).", authctxt.method->name); } + void userauth(Authctxt *authctxt, char *authlist) { - if (authctxt->methoddata!=NULL) { + if (authctxt->method != NULL && authctxt->method->cleanup != NULL) + authctxt->method->cleanup(authctxt); + + if (authctxt->methoddata) { xfree(authctxt->methoddata); - authctxt->methoddata=NULL; + authctxt->methoddata = NULL; } - if (authlist == NULL) { authlist = authctxt->authlist; } else { @@ -359,6 +485,12 @@ userauth(Authctxt *authctxt, char *authlist) if (method == NULL) fatal("Permission denied (%s).", authlist); authctxt->method = method; + + /* reset the per method handler */ + dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN, + SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); + + /* and try new method */ if (method->userauth(authctxt) != 0) { debug2("we sent a %s packet, wait for reply", method->name); break; @@ -368,38 +500,58 @@ userauth(Authctxt *authctxt, char *authlist) } } } + +/* ARGSUSED */ void -input_userauth_error(int type, int plen, void *ctxt) +input_userauth_error(int type, u_int32_t seq, void *ctxt) { fatal("input_userauth_error: bad message during authentication: " - "type %d", type); + "type %d", type); } + +/* ARGSUSED */ void -input_userauth_banner(int type, int plen, void *ctxt) +input_userauth_banner(int type, u_int32_t seq, void *ctxt) { - char *msg, *lang; + char *msg, *raw, *lang; + u_int len; + debug3("input_userauth_banner"); - msg = packet_get_string(NULL); + raw = packet_get_string(&len); lang = packet_get_string(NULL); - fprintf(stderr, "%s", msg); - xfree(msg); + if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) { + if (len > 65536) + len = 65536; + msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */ + strnvis(msg, raw, len * 4 + 1, VIS_SAFE|VIS_OCTAL); + fprintf(stderr, "%s", msg); + xfree(msg); + } + xfree(raw); xfree(lang); } + +/* ARGSUSED */ void -input_userauth_success(int type, int plen, void *ctxt) +input_userauth_success(int type, u_int32_t seq, void *ctxt) { Authctxt *authctxt = ctxt; if (authctxt == NULL) fatal("input_userauth_success: no authentication context"); - if (authctxt->authlist) + if (authctxt->authlist) { xfree(authctxt->authlist); - if (authctxt->methoddata) + authctxt->authlist = NULL; + } + if (authctxt->methoddata) { xfree(authctxt->methoddata); - clear_auth_state(authctxt); + authctxt->methoddata = NULL; + } authctxt->success = 1; /* break out */ } + +/* ARGSUSED */ void -input_userauth_failure(int type, int plen, void *ctxt) +input_userauth_failure(int type, u_int32_t seq, void *ctxt) { Authctxt *authctxt = ctxt; char *authlist = NULL; @@ -410,23 +562,27 @@ input_userauth_failure(int type, int plen, void *ctxt) authlist = packet_get_string(NULL); partial = packet_get_char(); - packet_done(); + packet_check_eom(); if (partial != 0) - log("Authenticated with partial success."); - debug("authentications that can continue: %s", authlist); + logit("Authenticated with partial success."); + debug("Authentications that can continue: %s", authlist); - clear_auth_state(authctxt); userauth(authctxt, authlist); } + +/* ARGSUSED */ void -input_userauth_pk_ok(int type, int plen, void *ctxt) +input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) { Authctxt *authctxt = ctxt; Key *key = NULL; + Identity *id = NULL; Buffer b; - int alen, blen, sent = 0; - char *pkalg, *pkblob, *fp; + int pktype, sent = 0; + u_int alen, blen; + char *pkalg, *fp; + u_char *pkblob; if (authctxt == NULL) fatal("input_userauth_pk_ok: no authentication context"); @@ -442,194 +598,395 @@ input_userauth_pk_ok(int type, int plen, void *ctxt) pkalg = packet_get_string(&alen); pkblob = packet_get_string(&blen); } - packet_done(); + packet_check_eom(); - debug("input_userauth_pk_ok: pkalg %s blen %d lastkey %p hint %d", - pkalg, blen, authctxt->last_key, authctxt->last_key_hint); + debug("Server accepts key: pkalg %s blen %u", pkalg, blen); - do { - if (authctxt->last_key == NULL || - authctxt->last_key_sign == NULL) { - debug("no last key or no sign cb"); - break; - } - if (key_type_from_name(pkalg) == KEY_UNSPEC) { - debug("unknown pkalg %s", pkalg); - break; - } - if ((key = key_from_blob(pkblob, blen)) == NULL) { - debug("no key from blob. pkalg %s", pkalg); - break; - } - fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); - debug2("input_userauth_pk_ok: fp %s", fp); - xfree(fp); - if (!key_equal(key, authctxt->last_key)) { - debug("key != last_key"); + if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { + debug("unknown pkalg %s", pkalg); + goto done; + } + if ((key = key_from_blob(pkblob, blen)) == NULL) { + debug("no key from blob. pkalg %s", pkalg); + goto done; + } + if (key->type != pktype) { + error("input_userauth_pk_ok: type mismatch " + "for decoded key (received %d, expected %d)", + key->type, pktype); + goto done; + } + fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); + debug2("input_userauth_pk_ok: fp %s", fp); + xfree(fp); + + /* + * search keys in the reverse order, because last candidate has been + * moved to the end of the queue. this also avoids confusion by + * duplicate keys + */ + TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { + if (key_equal(key, id->key)) { + sent = sign_and_send_pubkey(authctxt, id); break; } - sent = sign_and_send_pubkey(authctxt, key, - authctxt->last_key_sign); - } while(0); - + } +done: if (key != NULL) key_free(key); xfree(pkalg); xfree(pkblob); - /* unregister */ - clear_auth_state(authctxt); - dispatch_set(SSH2_MSG_USERAUTH_PK_OK, NULL); - - /* try another method if we did not send a packet*/ + /* try another method if we did not send a packet */ if (sent == 0) userauth(authctxt, NULL); - } #ifdef GSSAPI -int +int userauth_gssapi(Authctxt *authctxt) { - int i; - Gssctxt *gssctxt; - static int tries=0; + Gssctxt *gssctxt = NULL; + static gss_OID_set gss_supported = NULL; + static u_int mech = 0; + OM_uint32 min; + int ok = 0; + char *gss_host = NULL; + + if (!options.gss_authentication) { + verbose("GSSAPI authentication disabled."); + return 0; + } - /* For now, we only make one attempt at this. We could try offering - * the server different GSSAPI OIDs until we get bored, I suppose. - */ - if (tries++>0) return 0; + if (options.gss_trust_dns) + gss_host = (char *)get_canonical_hostname(1); + else + gss_host = (char *)authctxt->host; - gssctxt=xmalloc(sizeof(Gssctxt)); + /* Try one GSSAPI method at a time, rather than sending them all at + * once. */ - /* Initialise as much of our context as we can, so failures can be - * trapped before sending any packets. - */ - ssh_gssapi_build_ctx(gssctxt); - if (ssh_gssapi_import_name(gssctxt,authctxt->host)) { - return(0); + if (gss_supported == NULL) + if (GSS_ERROR(gss_indicate_mechs(&min, &gss_supported))) { + gss_supported = NULL; + return 0; + } + + /* Check to see if the mechanism is usable before we offer it */ + while (mech < gss_supported->count && !ok) { + /* My DER encoding requires length<128 */ + if (gss_supported->elements[mech].length < 128 && + ssh_gssapi_check_mechanism(&gssctxt, + &gss_supported->elements[mech], gss_host, + options.gss_client_identity)) { + ok = 1; /* Mechanism works */ + } else { + mech++; + } } + + if (!ok) + return 0; + authctxt->methoddata=(void *)gssctxt; - + packet_start(SSH2_MSG_USERAUTH_REQUEST); packet_put_cstring(authctxt->server_user); packet_put_cstring(authctxt->service); - packet_put_cstring(authctxt->method->name); - - /* FIXME: This assumes that our current GSSAPI implementation - * supports all of the mechanisms listed in supported_mechs. - * This may not be the case - we should use something along - * the lines of the code in gss_genr to remove the ones that - * aren't supported */ - packet_put_int(GSS_LAST_ENTRY); - for (i=0;imethod->name); + + packet_put_int(1); + + packet_put_int((gss_supported->elements[mech].length) + 2); + packet_put_char(SSH_GSS_OIDTYPE); + packet_put_char(gss_supported->elements[mech].length); + packet_put_raw(gss_supported->elements[mech].elements, + gss_supported->elements[mech].length); + + packet_send(); + + dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); + dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); + dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); + dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); + + mech++; /* Move along to next candidate */ + + return 1; +} + +static OM_uint32 +process_gssapi_token(void *ctxt, gss_buffer_t recv_tok) +{ + Authctxt *authctxt = ctxt; + Gssctxt *gssctxt = authctxt->methoddata; + gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; + gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; + gss_buffer_desc gssbuf; + OM_uint32 status, ms, flags; + Buffer b; + + status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, + recv_tok, &send_tok, &flags); + + if (send_tok.length > 0) { + if (GSS_ERROR(status)) + packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); + else + packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); + + packet_put_string(send_tok.value, send_tok.length); + packet_send(); + gss_release_buffer(&ms, &send_tok); + } + + if (status == GSS_S_COMPLETE) { + /* send either complete or MIC, depending on mechanism */ + if (strcmp(authctxt->method->name,"gssapi")==0 || + (!(flags & GSS_C_INTEG_FLAG))) { + packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); + packet_send(); + } else { + ssh_gssapi_buildmic(&b, authctxt->server_user, + authctxt->service, "gssapi-with-mic"); + + gssbuf.value = buffer_ptr(&b); + gssbuf.length = buffer_len(&b); + + status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); + + if (!GSS_ERROR(status)) { + packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); + packet_put_string(mic.value, mic.length); + + packet_send(); + } + + buffer_free(&b); + gss_release_buffer(&ms, &mic); + } + } + + return status; } +/* ARGSUSED */ void -input_gssapi_response(int type, int plen, void *ctxt) +input_gssapi_response(int type, u_int32_t plen, void *ctxt) { Authctxt *authctxt = ctxt; Gssctxt *gssctxt; - OM_uint32 status,ms; - int oidlen; - char *oidv; - gss_buffer_desc send_tok; - + u_int oidlen; + u_char *oidv; + if (authctxt == NULL) fatal("input_gssapi_response: no authentication context"); gssctxt = authctxt->methoddata; - + /* Setup our OID */ - oidv=packet_get_string(&oidlen); - ssh_gssapi_set_oid_data(gssctxt,oidv,oidlen); - - packet_done(); - - status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, - GSS_C_NO_BUFFER, &send_tok, - NULL); - if (GSS_ERROR(status)) { + oidv = packet_get_string(&oidlen); + + if (oidlen <= 2 || + oidv[0] != SSH_GSS_OIDTYPE || + oidv[1] != oidlen - 2) { + xfree(oidv); + debug("Badly encoded mechanism OID received"); + userauth(authctxt, NULL); + return; + } + + if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) + fatal("Server returned different OID than expected"); + + packet_check_eom(); + + xfree(oidv); + + if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) { /* Start again with next method on list */ debug("Trying to start again"); - userauth(authctxt,NULL); + userauth(authctxt, NULL); return; } - - /* We must have data to send */ - packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); - packet_put_string(send_tok.value,send_tok.length); - packet_send(); - packet_write_wait(); - gss_release_buffer(&ms, &send_tok); } +/* ARGSUSED */ void -input_gssapi_token(int type, int plen, void *ctxt) +input_gssapi_token(int type, u_int32_t plen, void *ctxt) { Authctxt *authctxt = ctxt; - Gssctxt *gssctxt; - gss_buffer_desc send_tok,recv_tok; + gss_buffer_desc recv_tok; OM_uint32 status; - + u_int slen; + if (authctxt == NULL) fatal("input_gssapi_response: no authentication context"); - gssctxt = authctxt->methoddata; - - recv_tok.value=packet_get_string(&recv_tok.length); - status=ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, - &recv_tok, &send_tok, NULL); + recv_tok.value = packet_get_string(&slen); + recv_tok.length = slen; /* safe typecast */ + + packet_check_eom(); + + status = process_gssapi_token(ctxt, &recv_tok); + + xfree(recv_tok.value); - packet_done(); - if (GSS_ERROR(status)) { /* Start again with the next method in the list */ - userauth(authctxt,NULL); + userauth(authctxt, NULL); return; } - - if (send_tok.length>0) { - packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); - packet_put_string(send_tok.value,send_tok.length); - packet_send(); - packet_write_wait(); - } - - if (status == GSS_S_COMPLETE) { - /* If that succeeded, send a exchange complete message */ - packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); - packet_send(); - packet_write_wait(); - } } +/* ARGSUSED */ +void +input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) +{ + Authctxt *authctxt = ctxt; + Gssctxt *gssctxt; + gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; + gss_buffer_desc recv_tok; + OM_uint32 status, ms; + u_int len; + + if (authctxt == NULL) + fatal("input_gssapi_response: no authentication context"); + gssctxt = authctxt->methoddata; + + recv_tok.value = packet_get_string(&len); + recv_tok.length = len; + + packet_check_eom(); + + /* Stick it into GSSAPI and see what it says */ + status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, + &recv_tok, &send_tok, NULL); + + xfree(recv_tok.value); + gss_release_buffer(&ms, &send_tok); + + /* Server will be returning a failed packet after this one */ +} + +/* ARGSUSED */ +void +input_gssapi_error(int type, u_int32_t plen, void *ctxt) +{ + OM_uint32 maj, min; + char *msg; + char *lang; + + maj=packet_get_int(); + min=packet_get_int(); + msg=packet_get_string(NULL); + lang=packet_get_string(NULL); + + packet_check_eom(); + + debug("Server GSSAPI Error:\n%s", msg); + xfree(msg); + xfree(lang); +} + +#ifdef GSI +extern +const gss_OID_desc * const gss_mech_globus_gssapi_openssl; +#define is_gsi_oid(oid) \ + (oid->length == gss_mech_globus_gssapi_openssl->length && \ + (memcmp(oid->elements, gss_mech_globus_gssapi_openssl->elements, \ + oid->length) == 0)) +#endif + int userauth_external(Authctxt *authctxt) { - static int attempt =0; + static int attempt = 0; - if (attempt++ >= 1) - return 0; + if (attempt++ >= 1) + return 0; - debug2("userauth_external"); - packet_start(SSH2_MSG_USERAUTH_REQUEST); - packet_put_cstring(authctxt->server_user); - packet_put_cstring(authctxt->service); - packet_put_cstring(authctxt->method->name); - packet_send(); - packet_write_wait(); - return 1; + /* The client MUST NOT try this method if initial key exchange + was not performed using a GSSAPI-based key exchange + method. */ + if (gss_kex_context == NULL) { + debug2("gsskex not performed, skipping external-keyx"); + return 0; + } + + debug2("userauth_external"); + packet_start(SSH2_MSG_USERAUTH_REQUEST); +#ifdef GSI + if (options.implicit && is_gsi_oid(gss_kex_context->oid)) { + packet_put_cstring(""); + } else { +#endif + packet_put_cstring(authctxt->server_user); +#ifdef GSI + } +#endif + packet_put_cstring(authctxt->service); + packet_put_cstring(authctxt->method->name); + packet_send(); + packet_write_wait(); + return 1; } +int +userauth_gsskeyex(Authctxt *authctxt) +{ + Buffer b; + gss_buffer_desc gssbuf; + gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; + OM_uint32 ms; + + static int attempt = 0; + if (attempt++ >= 1) + return (0); + + if (gss_kex_context == NULL) { + debug("No valid Key exchange context"); + return (0); + } + +#ifdef GSI + if (options.implicit && is_gsi_oid(gss_kex_context->oid)) { + ssh_gssapi_buildmic(&b, "", authctxt->service, "gssapi-keyex"); + } else { +#endif + ssh_gssapi_buildmic(&b, authctxt->server_user, authctxt->service, + "gssapi-keyex"); +#ifdef GSI + } +#endif + + gssbuf.value = buffer_ptr(&b); + gssbuf.length = buffer_len(&b); + + if (GSS_ERROR(ssh_gssapi_sign(gss_kex_context, &gssbuf, &mic))) { + buffer_free(&b); + return (0); + } + + packet_start(SSH2_MSG_USERAUTH_REQUEST); +#ifdef GSI + if (options.implicit && is_gsi_oid(gss_kex_context->oid)) { + packet_put_cstring(""); + } else { +#endif + packet_put_cstring(authctxt->server_user); +#ifdef GSI + } +#endif + packet_put_cstring(authctxt->service); + packet_put_cstring(authctxt->method->name); + packet_put_string(mic.value, mic.length); + packet_send(); + + buffer_free(&b); + gss_release_buffer(&ms, &mic); + + return (1); +} + #endif /* GSSAPI */ int @@ -642,20 +999,19 @@ userauth_none(Authctxt *authctxt) packet_put_cstring(authctxt->method->name); packet_send(); return 1; - } int userauth_passwd(Authctxt *authctxt) { static int attempt = 0; - char prompt[80]; + char prompt[150]; char *password; if (attempt++ >= options.number_of_password_prompts) return 0; - if(attempt != 1) + if (attempt != 1) error("Permission denied, please try again."); snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", @@ -671,35 +1027,322 @@ userauth_passwd(Authctxt *authctxt) xfree(password); packet_add_padding(64); packet_send(); + + dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, + &input_userauth_passwd_changereq); + return 1; } -static void -clear_auth_state(Authctxt *authctxt) +/* + * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST + */ +/* ARGSUSED */ +void +input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt) { - /* XXX clear authentication state */ - if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) { - debug3("clear_auth_state: key_free %p", authctxt->last_key); - key_free(authctxt->last_key); - } - authctxt->last_key = NULL; - authctxt->last_key_hint = -2; - authctxt->last_key_sign = NULL; + Authctxt *authctxt = ctxt; + char *info, *lang, *password = NULL, *retype = NULL; + char prompt[150]; + + debug2("input_userauth_passwd_changereq"); + + if (authctxt == NULL) + fatal("input_userauth_passwd_changereq: " + "no authentication context"); + + info = packet_get_string(NULL); + lang = packet_get_string(NULL); + if (strlen(info) > 0) + logit("%s", info); + xfree(info); + xfree(lang); + packet_start(SSH2_MSG_USERAUTH_REQUEST); + packet_put_cstring(authctxt->server_user); + packet_put_cstring(authctxt->service); + packet_put_cstring(authctxt->method->name); + packet_put_char(1); /* additional info */ + snprintf(prompt, sizeof(prompt), + "Enter %.30s@%.128s's old password: ", + authctxt->server_user, authctxt->host); + password = read_passphrase(prompt, 0); + packet_put_cstring(password); + memset(password, 0, strlen(password)); + xfree(password); + password = NULL; + while (password == NULL) { + snprintf(prompt, sizeof(prompt), + "Enter %.30s@%.128s's new password: ", + authctxt->server_user, authctxt->host); + password = read_passphrase(prompt, RP_ALLOW_EOF); + if (password == NULL) { + /* bail out */ + return; + } + snprintf(prompt, sizeof(prompt), + "Retype %.30s@%.128s's new password: ", + authctxt->server_user, authctxt->host); + retype = read_passphrase(prompt, 0); + if (strcmp(password, retype) != 0) { + memset(password, 0, strlen(password)); + xfree(password); + logit("Mismatch; try again, EOF to quit."); + password = NULL; + } + memset(retype, 0, strlen(retype)); + xfree(retype); + } + packet_put_cstring(password); + memset(password, 0, strlen(password)); + xfree(password); + packet_add_padding(64); + packet_send(); + + dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, + &input_userauth_passwd_changereq); } +#ifdef JPAKE +static char * +pw_encrypt(const char *password, const char *crypt_scheme, const char *salt) +{ + /* OpenBSD crypt(3) handles all of these */ + if (strcmp(crypt_scheme, "crypt") == 0 || + strcmp(crypt_scheme, "bcrypt") == 0 || + strcmp(crypt_scheme, "md5crypt") == 0 || + strcmp(crypt_scheme, "crypt-extended") == 0) + return xstrdup(crypt(password, salt)); + error("%s: unsupported password encryption scheme \"%.100s\"", + __func__, crypt_scheme); + return NULL; +} + +static BIGNUM * +jpake_password_to_secret(Authctxt *authctxt, const char *crypt_scheme, + const char *salt) +{ + char prompt[256], *password, *crypted; + u_char *secret; + u_int secret_len; + BIGNUM *ret; + + snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password (JPAKE): ", + authctxt->server_user, authctxt->host); + password = read_passphrase(prompt, 0); + + if ((crypted = pw_encrypt(password, crypt_scheme, salt)) == NULL) { + logit("Disabling %s authentication", authctxt->method->name); + authctxt->method->enabled = NULL; + /* Continue with an empty password to fail gracefully */ + crypted = xstrdup(""); + } + +#ifdef JPAKE_DEBUG + debug3("%s: salt = %s", __func__, salt); + debug3("%s: scheme = %s", __func__, crypt_scheme); + debug3("%s: crypted = %s", __func__, crypted); +#endif + + if (hash_buffer(crypted, strlen(crypted), EVP_sha256(), + &secret, &secret_len) != 0) + fatal("%s: hash_buffer", __func__); + + bzero(password, strlen(password)); + bzero(crypted, strlen(crypted)); + xfree(password); + xfree(crypted); + + if ((ret = BN_bin2bn(secret, secret_len, NULL)) == NULL) + fatal("%s: BN_bin2bn (secret)", __func__); + bzero(secret, secret_len); + xfree(secret); + + return ret; +} + +/* ARGSUSED */ +void +input_userauth_jpake_server_step1(int type, u_int32_t seq, void *ctxt) +{ + Authctxt *authctxt = ctxt; + struct jpake_ctx *pctx = authctxt->methoddata; + u_char *x3_proof, *x4_proof, *x2_s_proof; + u_int x3_proof_len, x4_proof_len, x2_s_proof_len; + char *crypt_scheme, *salt; + + /* Disable this message */ + dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, NULL); + + if ((pctx->g_x3 = BN_new()) == NULL || + (pctx->g_x4 = BN_new()) == NULL) + fatal("%s: BN_new", __func__); + + /* Fetch step 1 values */ + crypt_scheme = packet_get_string(NULL); + salt = packet_get_string(NULL); + pctx->server_id = packet_get_string(&pctx->server_id_len); + packet_get_bignum2(pctx->g_x3); + packet_get_bignum2(pctx->g_x4); + x3_proof = packet_get_string(&x3_proof_len); + x4_proof = packet_get_string(&x4_proof_len); + packet_check_eom(); + + JPAKE_DEBUG_CTX((pctx, "step 1 received in %s", __func__)); + + /* Obtain password and derive secret */ + pctx->s = jpake_password_to_secret(authctxt, crypt_scheme, salt); + bzero(crypt_scheme, strlen(crypt_scheme)); + bzero(salt, strlen(salt)); + xfree(crypt_scheme); + xfree(salt); + JPAKE_DEBUG_BN((pctx->s, "%s: s = ", __func__)); + + /* Calculate step 2 values */ + jpake_step2(pctx->grp, pctx->s, pctx->g_x1, + pctx->g_x3, pctx->g_x4, pctx->x2, + pctx->server_id, pctx->server_id_len, + pctx->client_id, pctx->client_id_len, + x3_proof, x3_proof_len, + x4_proof, x4_proof_len, + &pctx->a, + &x2_s_proof, &x2_s_proof_len); + + bzero(x3_proof, x3_proof_len); + bzero(x4_proof, x4_proof_len); + xfree(x3_proof); + xfree(x4_proof); + + JPAKE_DEBUG_CTX((pctx, "step 2 sending in %s", __func__)); + + /* Send values for step 2 */ + packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP2); + packet_put_bignum2(pctx->a); + packet_put_string(x2_s_proof, x2_s_proof_len); + packet_send(); + + bzero(x2_s_proof, x2_s_proof_len); + xfree(x2_s_proof); + + /* Expect step 2 packet from peer */ + dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, + input_userauth_jpake_server_step2); +} + +/* ARGSUSED */ +void +input_userauth_jpake_server_step2(int type, u_int32_t seq, void *ctxt) +{ + Authctxt *authctxt = ctxt; + struct jpake_ctx *pctx = authctxt->methoddata; + u_char *x4_s_proof; + u_int x4_s_proof_len; + + /* Disable this message */ + dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, NULL); + + if ((pctx->b = BN_new()) == NULL) + fatal("%s: BN_new", __func__); + + /* Fetch step 2 values */ + packet_get_bignum2(pctx->b); + x4_s_proof = packet_get_string(&x4_s_proof_len); + packet_check_eom(); + + JPAKE_DEBUG_CTX((pctx, "step 2 received in %s", __func__)); + + /* Derive shared key and calculate confirmation hash */ + jpake_key_confirm(pctx->grp, pctx->s, pctx->b, + pctx->x2, pctx->g_x1, pctx->g_x2, pctx->g_x3, pctx->g_x4, + pctx->client_id, pctx->client_id_len, + pctx->server_id, pctx->server_id_len, + session_id2, session_id2_len, + x4_s_proof, x4_s_proof_len, + &pctx->k, + &pctx->h_k_cid_sessid, &pctx->h_k_cid_sessid_len); + + bzero(x4_s_proof, x4_s_proof_len); + xfree(x4_s_proof); + + JPAKE_DEBUG_CTX((pctx, "confirm sending in %s", __func__)); + + /* Send key confirmation proof */ + packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_CONFIRM); + packet_put_string(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len); + packet_send(); + + /* Expect confirmation from peer */ + dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, + input_userauth_jpake_server_confirm); +} + +/* ARGSUSED */ +void +input_userauth_jpake_server_confirm(int type, u_int32_t seq, void *ctxt) +{ + Authctxt *authctxt = ctxt; + struct jpake_ctx *pctx = authctxt->methoddata; + + /* Disable this message */ + dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, NULL); + + pctx->h_k_sid_sessid = packet_get_string(&pctx->h_k_sid_sessid_len); + packet_check_eom(); + + JPAKE_DEBUG_CTX((pctx, "confirm received in %s", __func__)); + + /* Verify expected confirmation hash */ + if (jpake_check_confirm(pctx->k, + pctx->server_id, pctx->server_id_len, + session_id2, session_id2_len, + pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len) == 1) + debug("%s: %s success", __func__, authctxt->method->name); + else { + debug("%s: confirmation mismatch", __func__); + /* XXX stash this so if auth succeeds then we can warn/kill */ + } + + userauth_jpake_cleanup(authctxt); +} +#endif /* JPAKE */ + static int -sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback) +identity_sign(Identity *id, u_char **sigp, u_int *lenp, + u_char *data, u_int datalen) +{ + Key *prv; + int ret; + + /* the agent supports this key */ + if (id->ac) + return (ssh_agent_sign(id->ac, id->key, sigp, lenp, + data, datalen)); + /* + * we have already loaded the private key or + * the private key is stored in external hardware + */ + if (id->isprivate || (id->key->flags & KEY_FLAG_EXT)) + return (key_sign(id->key, sigp, lenp, data, datalen)); + /* load the private key from the file */ + if ((prv = load_identity_file(id->filename)) == NULL) + return (-1); + ret = key_sign(prv, sigp, lenp, data, datalen); + key_free(prv); + return (ret); +} + +static int +sign_and_send_pubkey(Authctxt *authctxt, Identity *id) { Buffer b; u_char *blob, *signature; - int bloblen, slen; - int skip = 0; + u_int bloblen, slen; + u_int skip = 0; int ret = -1; int have_sig = 1; debug3("sign_and_send_pubkey"); - if (key_to_blob(k, &blob, &bloblen) == 0) { + if (key_to_blob(id->key, &blob, &bloblen) == 0) { /* we cannot handle this key */ debug3("sign_and_send_pubkey: cannot handle key"); return 0; @@ -724,12 +1367,12 @@ sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback) } else { buffer_put_cstring(&b, authctxt->method->name); buffer_put_char(&b, have_sig); - buffer_put_cstring(&b, key_ssh_name(k)); + buffer_put_cstring(&b, key_ssh_name(id->key)); } buffer_put_string(&b, blob, bloblen); /* generate signature */ - ret = (*sign_callback)(authctxt, k, &signature, &slen, + ret = identity_sign(id, &signature, &slen, buffer_ptr(&b), buffer_len(&b)); if (ret == -1) { xfree(blob); @@ -749,7 +1392,7 @@ sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback) buffer_put_cstring(&b, authctxt->method->name); buffer_put_char(&b, have_sig); if (!(datafellows & SSH_BUG_PKAUTH)) - buffer_put_cstring(&b, key_ssh_name(k)); + buffer_put_cstring(&b, key_ssh_name(id->key)); buffer_put_string(&b, blob, bloblen); } xfree(blob); @@ -773,23 +1416,19 @@ sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback) } static int -send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback, - int hint) +send_pubkey_test(Authctxt *authctxt, Identity *id) { u_char *blob; - int bloblen, have_sig = 0; + u_int bloblen, have_sig = 0; debug3("send_pubkey_test"); - if (key_to_blob(k, &blob, &bloblen) == 0) { + if (key_to_blob(id->key, &blob, &bloblen) == 0) { /* we cannot handle this key */ debug3("send_pubkey_test: cannot handle key"); return 0; } /* register callback for USERAUTH_PK_OK message */ - authctxt->last_key_sign = sign_callback; - authctxt->last_key_hint = hint; - authctxt->last_key = k; dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); packet_start(SSH2_MSG_USERAUTH_REQUEST); @@ -798,7 +1437,7 @@ send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback, packet_put_cstring(authctxt->method->name); packet_put_char(have_sig); if (!(datafellows & SSH_BUG_PKAUTH)) - packet_put_cstring(key_ssh_name(k)); + packet_put_cstring(key_ssh_name(id->key)); packet_put_string(blob, bloblen); xfree(blob); packet_send(); @@ -810,24 +1449,26 @@ load_identity_file(char *filename) { Key *private; char prompt[300], *passphrase; - int quit, i; + int perm_ok, quit, i; struct stat st; if (stat(filename, &st) < 0) { debug3("no such identity: %s", filename); return NULL; } - private = key_load_private_type(KEY_UNSPEC, filename, "", NULL); + private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok); + if (!perm_ok) + return NULL; if (private == NULL) { if (options.batch_mode) return NULL; snprintf(prompt, sizeof prompt, - "Enter passphrase for key '%.100s': ", filename); + "Enter passphrase for key '%.100s': ", filename); for (i = 0; i < options.number_of_password_prompts; i++) { passphrase = read_passphrase(prompt, 0); if (strcmp(passphrase, "") != 0) { - private = key_load_private_type(KEY_UNSPEC, filename, - passphrase, NULL); + private = key_load_private_type(KEY_UNSPEC, + filename, passphrase, NULL, NULL); quit = 0; } else { debug2("no passphrase given, try next key"); @@ -843,103 +1484,133 @@ load_identity_file(char *filename) return private; } -static int -identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, - u_char *data, int datalen) -{ - Key *private; - int idx, ret; - - idx = authctxt->last_key_hint; - if (idx < 0) - return -1; - - /* private key is stored in external hardware */ - if (options.identity_keys[idx]->flags & KEY_FLAG_EXT) - return key_sign(options.identity_keys[idx], sigp, lenp, data, datalen); - - private = load_identity_file(options.identity_files[idx]); - if (private == NULL) - return -1; - ret = key_sign(private, sigp, lenp, data, datalen); - key_free(private); - return ret; -} - -static int -agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, - u_char *data, int datalen) -{ - return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen); -} - -static int -key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, - u_char *data, int datalen) +/* + * try keys in the following order: + * 1. agent keys that are found in the config file + * 2. other agent keys + * 3. keys that are only listed in the config file + */ +static void +pubkey_prepare(Authctxt *authctxt) { - return key_sign(key, sigp, lenp, data, datalen); + Identity *id; + Idlist agent, files, *preferred; + Key *key; + AuthenticationConnection *ac; + char *comment; + int i, found; + + TAILQ_INIT(&agent); /* keys from the agent */ + TAILQ_INIT(&files); /* keys from the config file */ + preferred = &authctxt->keys; + TAILQ_INIT(preferred); /* preferred order of keys */ + + /* list of keys stored in the filesystem */ + for (i = 0; i < options.num_identity_files; i++) { + key = options.identity_keys[i]; + if (key && key->type == KEY_RSA1) + continue; + options.identity_keys[i] = NULL; + id = xcalloc(1, sizeof(*id)); + id->key = key; + id->filename = xstrdup(options.identity_files[i]); + TAILQ_INSERT_TAIL(&files, id, next); + } + /* list of keys supported by the agent */ + if ((ac = ssh_get_authentication_connection())) { + for (key = ssh_get_first_identity(ac, &comment, 2); + key != NULL; + key = ssh_get_next_identity(ac, &comment, 2)) { + found = 0; + TAILQ_FOREACH(id, &files, next) { + /* agent keys from the config file are preferred */ + if (key_equal(key, id->key)) { + key_free(key); + xfree(comment); + TAILQ_REMOVE(&files, id, next); + TAILQ_INSERT_TAIL(preferred, id, next); + id->ac = ac; + found = 1; + break; + } + } + if (!found && !options.identities_only) { + id = xcalloc(1, sizeof(*id)); + id->key = key; + id->filename = comment; + id->ac = ac; + TAILQ_INSERT_TAIL(&agent, id, next); + } + } + /* append remaining agent keys */ + for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { + TAILQ_REMOVE(&agent, id, next); + TAILQ_INSERT_TAIL(preferred, id, next); + } + authctxt->agent = ac; + } + /* append remaining keys from the config file */ + for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { + TAILQ_REMOVE(&files, id, next); + TAILQ_INSERT_TAIL(preferred, id, next); + } + TAILQ_FOREACH(id, preferred, next) { + debug2("key: %s (%p)", id->filename, id->key); + } } -static int -userauth_pubkey_agent(Authctxt *authctxt) +static void +pubkey_cleanup(Authctxt *authctxt) { - static int called = 0; - int ret = 0; - char *comment; - Key *k; - - if (called == 0) { - if (ssh_get_num_identities(authctxt->agent, 2) == 0) - debug2("userauth_pubkey_agent: no keys at all"); - called = 1; + Identity *id; + + if (authctxt->agent != NULL) + ssh_close_authentication_connection(authctxt->agent); + for (id = TAILQ_FIRST(&authctxt->keys); id; + id = TAILQ_FIRST(&authctxt->keys)) { + TAILQ_REMOVE(&authctxt->keys, id, next); + if (id->key) + key_free(id->key); + if (id->filename) + xfree(id->filename); + xfree(id); } - k = ssh_get_next_identity(authctxt->agent, &comment, 2); - if (k == NULL) { - debug2("userauth_pubkey_agent: no more keys"); - } else { - debug("userauth_pubkey_agent: testing agent key %s", comment); - xfree(comment); - ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1); - if (ret == 0) - key_free(k); - } - if (ret == 0) - debug2("userauth_pubkey_agent: no message sent"); - return ret; } int userauth_pubkey(Authctxt *authctxt) { - static int idx = 0; + Identity *id; int sent = 0; - Key *key; - char *filename; - - if (authctxt->agent != NULL) { - do { - sent = userauth_pubkey_agent(authctxt); - } while(!sent && authctxt->agent->howmany > 0); - } - while (!sent && idx < options.num_identity_files) { - key = options.identity_keys[idx]; - filename = options.identity_files[idx]; - if (key == NULL) { - debug("try privkey: %s", filename); - key = load_identity_file(filename); - if (key != NULL) { - sent = sign_and_send_pubkey(authctxt, key, - key_sign_cb); - key_free(key); + + while ((id = TAILQ_FIRST(&authctxt->keys))) { + if (id->tried++) + return (0); + /* move key to the end of the queue */ + TAILQ_REMOVE(&authctxt->keys, id, next); + TAILQ_INSERT_TAIL(&authctxt->keys, id, next); + /* + * send a test message if we have the public key. for + * encrypted keys we cannot do this and have to load the + * private key instead + */ + if (id->key && id->key->type != KEY_RSA1) { + debug("Offering public key: %s", id->filename); + sent = send_pubkey_test(authctxt, id); + } else if (id->key == NULL) { + debug("Trying private key: %s", id->filename); + id->key = load_identity_file(id->filename); + if (id->key != NULL) { + id->isprivate = 1; + sent = sign_and_send_pubkey(authctxt, id); + key_free(id->key); + id->key = NULL; } - } else if (key->type != KEY_RSA1) { - debug("try pubkey: %s", filename); - sent = send_pubkey_test(authctxt, key, - identity_sign_cb, idx); } - idx++; + if (sent) + return (sent); } - return sent; + return (0); } /* @@ -977,7 +1648,7 @@ userauth_kbdint(Authctxt *authctxt) * parse INFO_REQUEST, prompt user and send INFO_RESPONSE */ void -input_userauth_info_req(int type, int plen, void *ctxt) +input_userauth_info_req(int type, u_int32_t seq, void *ctxt) { Authctxt *authctxt = ctxt; char *name, *inst, *lang, *prompt, *response; @@ -995,9 +1666,9 @@ input_userauth_info_req(int type, int plen, void *ctxt) inst = packet_get_string(NULL); lang = packet_get_string(NULL); if (strlen(name) > 0) - log("%s", name); + logit("%s", name); if (strlen(inst) > 0) - log("%s", inst); + logit("%s", inst); xfree(name); xfree(inst); xfree(lang); @@ -1024,39 +1695,111 @@ input_userauth_info_req(int type, int plen, void *ctxt) xfree(response); xfree(prompt); } - packet_done(); /* done with parsing incoming message. */ + packet_check_eom(); /* done with parsing incoming message. */ packet_add_padding(64); packet_send(); } -/* - * this will be move to an external program (ssh-keysign) ASAP. ssh-keysign - * will be setuid-root and the sbit can be removed from /usr/bin/ssh. - */ +static int +ssh_keysign(Key *key, u_char **sigp, u_int *lenp, + u_char *data, u_int datalen) +{ + Buffer b; + struct stat st; + pid_t pid; + int to[2], from[2], status, version = 2; + + debug2("ssh_keysign called"); + + if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { + error("ssh_keysign: no installed: %s", strerror(errno)); + return -1; + } + if (fflush(stdout) != 0) + error("ssh_keysign: fflush: %s", strerror(errno)); + if (pipe(to) < 0) { + error("ssh_keysign: pipe: %s", strerror(errno)); + return -1; + } + if (pipe(from) < 0) { + error("ssh_keysign: pipe: %s", strerror(errno)); + return -1; + } + if ((pid = fork()) < 0) { + error("ssh_keysign: fork: %s", strerror(errno)); + return -1; + } + if (pid == 0) { + permanently_drop_suid(getuid()); + close(from[0]); + if (dup2(from[1], STDOUT_FILENO) < 0) + fatal("ssh_keysign: dup2: %s", strerror(errno)); + close(to[1]); + if (dup2(to[0], STDIN_FILENO) < 0) + fatal("ssh_keysign: dup2: %s", strerror(errno)); + close(from[1]); + close(to[0]); + execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0); + fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN, + strerror(errno)); + } + close(from[1]); + close(to[0]); + + buffer_init(&b); + buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */ + buffer_put_string(&b, data, datalen); + if (ssh_msg_send(to[1], version, &b) == -1) + fatal("ssh_keysign: couldn't send request"); + + if (ssh_msg_recv(from[0], &b) < 0) { + error("ssh_keysign: no reply"); + buffer_free(&b); + return -1; + } + close(from[0]); + close(to[1]); + + while (waitpid(pid, &status, 0) < 0) + if (errno != EINTR) + break; + + if (buffer_get_char(&b) != version) { + error("ssh_keysign: bad version"); + buffer_free(&b); + return -1; + } + *sigp = buffer_get_string(&b, lenp); + buffer_free(&b); + + return 0; +} + int userauth_hostbased(Authctxt *authctxt) { Key *private = NULL; + Sensitive *sensitive = authctxt->sensitive; Buffer b; u_char *signature, *blob; - char *chost, *pkalg, *p; + char *chost, *pkalg, *p, myname[NI_MAXHOST]; const char *service; u_int blen, slen; int ok, i, len, found = 0; /* check for a useful key */ - for (i = 0; i < authctxt->nkeys; i++) { - private = authctxt->keys[i]; + for (i = 0; i < sensitive->nkeys; i++) { + private = sensitive->keys[i]; if (private && private->type != KEY_RSA1) { found = 1; /* we take and free the key */ - authctxt->keys[i] = NULL; + sensitive->keys[i] = NULL; break; } } if (!found) { - debug("userauth_hostbased: no more client hostkeys"); + debug("No more client hostkeys for hostbased authentication."); return 0; } if (key_to_blob(private, &blob, &blen) == 0) { @@ -1064,17 +1807,26 @@ userauth_hostbased(Authctxt *authctxt) return 0; } /* figure out a name for the client host */ - p = get_local_name(packet_get_connection_in()); + p = NULL; + if (packet_connection_is_on_socket()) + p = get_local_name(packet_get_connection_in()); + if (p == NULL) { + if (gethostname(myname, sizeof(myname)) == -1) { + verbose("userauth_hostbased: gethostname: %s", + strerror(errno)); + } else + p = xstrdup(myname); + } if (p == NULL) { error("userauth_hostbased: cannot get local ipaddr/name"); key_free(private); + xfree(blob); return 0; } len = strlen(p) + 2; - chost = xmalloc(len); - strlcpy(chost, p, len); - strlcat(chost, ".", len); + xasprintf(&chost, "%s.", p); debug2("userauth_hostbased: chost %s", chost); + xfree(p); service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : authctxt->service; @@ -1093,13 +1845,19 @@ userauth_hostbased(Authctxt *authctxt) #ifdef DEBUG_PK buffer_dump(&b); #endif - ok = key_sign(private, &signature, &slen, buffer_ptr(&b), buffer_len(&b)); + if (sensitive->external_keysign) + ok = ssh_keysign(private, &signature, &slen, + buffer_ptr(&b), buffer_len(&b)); + else + ok = key_sign(private, &signature, &slen, + buffer_ptr(&b), buffer_len(&b)); key_free(private); buffer_free(&b); if (ok != 0) { error("key_sign failed"); xfree(chost); xfree(pkalg); + xfree(blob); return 0; } packet_start(SSH2_MSG_USERAUTH_REQUEST); @@ -1115,11 +1873,82 @@ userauth_hostbased(Authctxt *authctxt) xfree(signature); xfree(chost); xfree(pkalg); + xfree(blob); + + packet_send(); + return 1; +} + +#ifdef JPAKE +int +userauth_jpake(Authctxt *authctxt) +{ + struct jpake_ctx *pctx; + u_char *x1_proof, *x2_proof; + u_int x1_proof_len, x2_proof_len; + static int attempt = 0; /* XXX share with userauth_password's? */ + + if (attempt++ >= options.number_of_password_prompts) + return 0; + if (attempt != 1) + error("Permission denied, please try again."); + + if (authctxt->methoddata != NULL) + fatal("%s: authctxt->methoddata already set (%p)", + __func__, authctxt->methoddata); + + authctxt->methoddata = pctx = jpake_new(); + /* + * Send request immediately, to get the protocol going while + * we do the initial computations. + */ + packet_start(SSH2_MSG_USERAUTH_REQUEST); + packet_put_cstring(authctxt->server_user); + packet_put_cstring(authctxt->service); + packet_put_cstring(authctxt->method->name); + packet_send(); + packet_write_wait(); + + jpake_step1(pctx->grp, + &pctx->client_id, &pctx->client_id_len, + &pctx->x1, &pctx->x2, &pctx->g_x1, &pctx->g_x2, + &x1_proof, &x1_proof_len, + &x2_proof, &x2_proof_len); + + JPAKE_DEBUG_CTX((pctx, "step 1 sending in %s", __func__)); + + packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP1); + packet_put_string(pctx->client_id, pctx->client_id_len); + packet_put_bignum2(pctx->g_x1); + packet_put_bignum2(pctx->g_x2); + packet_put_string(x1_proof, x1_proof_len); + packet_put_string(x2_proof, x2_proof_len); packet_send(); + + bzero(x1_proof, x1_proof_len); + bzero(x2_proof, x2_proof_len); + xfree(x1_proof); + xfree(x2_proof); + + /* Expect step 1 packet from peer */ + dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, + input_userauth_jpake_server_step1); + return 1; } +void +userauth_jpake_cleanup(Authctxt *authctxt) +{ + debug3("%s: clean up", __func__); + if (authctxt->methoddata != NULL) { + jpake_free(authctxt->methoddata); + authctxt->methoddata = NULL; + } +} +#endif /* JPAKE */ + /* find auth method */ /* @@ -1156,6 +1985,7 @@ authmethod_lookup(const char *name) static Authmethod *current = NULL; static char *supported = NULL; static char *preferred = NULL; + /* * Given the authentication method list sent by the server, return the * next method we should try. If the server initially sends a nil list, @@ -1164,9 +1994,8 @@ static char *preferred = NULL; static Authmethod * authmethod_get(char *authlist) { - char *name = NULL; - int next; + u_int next; /* Use a suitable default if we're passed a nil list. */ if (authlist == NULL || strlen(authlist) == 0) @@ -1185,7 +2014,7 @@ authmethod_get(char *authlist) for (;;) { if ((name = match_list(preferred, supported, &next)) == NULL) { - debug("no more auth methods to try"); + debug("No more authentication methods to try."); current = NULL; return NULL; } @@ -1195,28 +2024,30 @@ authmethod_get(char *authlist) if ((current = authmethod_lookup(name)) != NULL && authmethod_is_enabled(current)) { debug3("authmethod_is_enabled %s", name); - debug("next auth method to try is %s", name); + debug("Next authentication method: %s", name); return current; } } } - -#define DELIM "," - static char * authmethods_get(void) { Authmethod *method = NULL; - char buf[1024]; + Buffer b; + char *list; - buf[0] = '\0'; + buffer_init(&b); for (method = authmethods; method->name != NULL; method++) { if (authmethod_is_enabled(method)) { - if (buf[0] != '\0') - strlcat(buf, DELIM, sizeof buf); - strlcat(buf, method->name, sizeof buf); + if (buffer_len(&b) > 0) + buffer_append(&b, ",", 1); + buffer_append(&b, method->name, strlen(method->name)); } } - return xstrdup(buf); + buffer_append(&b, "\0", 1); + list = xstrdup(buffer_ptr(&b)); + buffer_free(&b); + return list; } +