X-Git-Url: http://andersk.mit.edu/gitweb/gssapi-openssh.git/blobdiff_plain/fa0f0f455ac5f0d6e3e0597842e9f4f4fe58d2b1..HEAD:/openssh/sshconnect2.c diff --git a/openssh/sshconnect2.c b/openssh/sshconnect2.c index 16401c6..c4136d5 100644 --- a/openssh/sshconnect2.c +++ b/openssh/sshconnect2.c @@ -1,6 +1,7 @@ -/* $OpenBSD: sshconnect2.c,v 1.164 2007/05/17 23:53:41 jolan Exp $ */ +/* $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 @@ -38,6 +39,9 @@ #include #include #include +#if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H) +#include +#endif #include "openbsd-compat/sys-queue.h" @@ -64,6 +68,8 @@ #include "msg.h" #include "pathnames.h" #include "uidswap.h" +#include "schnorr.h" +#include "jpake.h" #ifdef GSSAPI #include "ssh-gss.h" @@ -80,6 +86,16 @@ extern Kex *xxx_kex; 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 */ @@ -124,7 +140,7 @@ ssh_kex2(char *host, struct sockaddr *hostaddr) else gss_host = host; - gss = ssh_gssapi_client_mechanisms(gss_host); + gss = ssh_gssapi_client_mechanisms(gss_host, options.gss_client_identity); if (gss) { debug("Offering GSSAPI proposal: %s", gss); xasprintf(&myproposal[PROPOSAL_KEX_ALGS], @@ -140,8 +156,7 @@ ssh_kex2(char *host, struct sockaddr *hostaddr) if (options.ciphers != NULL) { myproposal[PROPOSAL_ENC_ALGS_CTOS] = myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; - } - + } myproposal[PROPOSAL_ENC_ALGS_CTOS] = compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); myproposal[PROPOSAL_ENC_ALGS_STOC] = @@ -168,11 +183,12 @@ ssh_kex2(char *host, struct sockaddr *hostaddr) 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(options.rekey_limit); + packet_set_rekey_limit((u_int32_t)options.rekey_limit); /* start key exchange */ kex = kex_setup(myproposal); @@ -181,18 +197,23 @@ ssh_kex2(char *host, struct sockaddr *hostaddr) kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; #ifdef GSSAPI - kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_client; - kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_client; - kex->kex[KEX_GSS_GEX_SHA1] = kexgss_client; + 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; #ifdef GSSAPI - kex->gss_deleg_creds = options.gss_deleg_creds; - kex->gss_trust_dns = options.gss_trust_dns; - kex->gss_host = gss_host; + 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; @@ -251,6 +272,7 @@ 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 */ }; @@ -262,19 +284,21 @@ 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_kerberos(Authctxt *); +int userauth_jpake(Authctxt *); + +void userauth_jpake_cleanup(Authctxt *); #ifdef GSSAPI -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 *); @@ -298,42 +322,48 @@ Authmethod authmethods[] = { #ifdef GSSAPI {"gssapi-keyex", userauth_gsskeyex, - &options.gss_authentication, - NULL}, - {"external-keyx", - userauth_external, + NULL, &options.gss_authentication, NULL}, {"gssapi-with-mic", userauth_gssapi, - &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 @@ -423,6 +453,9 @@ ssh_userauth2(const char *local_user, const char *server_user, char *host, void userauth(Authctxt *authctxt, char *authlist) { + if (authctxt->method != NULL && authctxt->method->cleanup != NULL) + authctxt->method->cleanup(authctxt); + if (authctxt->methoddata) { xfree(authctxt->methoddata); authctxt->methoddata = NULL; @@ -455,6 +488,7 @@ userauth(Authctxt *authctxt, char *authlist) } } +/* ARGSUSED */ void input_userauth_error(int type, u_int32_t seq, void *ctxt) { @@ -462,20 +496,29 @@ input_userauth_error(int type, u_int32_t seq, void *ctxt) "type %d", type); } +/* ARGSUSED */ void 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); - if (options.log_level >= SYSLOG_LEVEL_INFO) + 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(msg); + } + xfree(raw); xfree(lang); } +/* ARGSUSED */ void input_userauth_success(int type, u_int32_t seq, void *ctxt) { @@ -493,6 +536,7 @@ input_userauth_success(int type, u_int32_t seq, void *ctxt) authctxt->success = 1; /* break out */ } +/* ARGSUSED */ void input_userauth_failure(int type, u_int32_t seq, void *ctxt) { @@ -513,6 +557,8 @@ input_userauth_failure(int type, u_int32_t seq, void *ctxt) userauth(authctxt, authlist); } + +/* ARGSUSED */ void input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) { @@ -608,14 +654,18 @@ userauth_gssapi(Authctxt *authctxt) * once. */ if (gss_supported == NULL) - gss_indicate_mechs(&min, &gss_supported); + 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)) { + &gss_supported->elements[mech], gss_host, + options.gss_client_identity)) { ok = 1; /* Mechanism works */ } else { mech++; @@ -707,6 +757,7 @@ process_gssapi_token(void *ctxt, gss_buffer_t recv_tok) return status; } +/* ARGSUSED */ void input_gssapi_response(int type, u_int32_t plen, void *ctxt) { @@ -746,6 +797,7 @@ input_gssapi_response(int type, u_int32_t plen, void *ctxt) } } +/* ARGSUSED */ void input_gssapi_token(int type, u_int32_t plen, void *ctxt) { @@ -773,6 +825,7 @@ input_gssapi_token(int type, u_int32_t plen, void *ctxt) } } +/* ARGSUSED */ void input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) { @@ -802,6 +855,7 @@ input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) /* Server will be returning a failed packet after this one */ } +/* ARGSUSED */ void input_gssapi_error(int type, u_int32_t plen, void *ctxt) { @@ -830,39 +884,6 @@ const gss_OID_desc * const gss_mech_globus_gssapi_openssl; oid->length) == 0)) #endif -int -userauth_external(Authctxt *authctxt) -{ - static int attempt = 0; - - if (attempt++ >= 1) - return 0; - - /* 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) { @@ -881,12 +902,12 @@ userauth_gsskeyex(Authctxt *authctxt) } #ifdef GSI - if (options.implicit && is_gsi_oid(gss_kex_context->oid)) { - ssh_gssapi_buildmic(&b, "", authctxt->service, "gssapi-keyex"); + 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"); + ssh_gssapi_buildmic(&b, authctxt->server_user, authctxt->service, + "gssapi-keyex"); #ifdef GSI } #endif @@ -901,8 +922,8 @@ userauth_gsskeyex(Authctxt *authctxt) packet_start(SSH2_MSG_USERAUTH_REQUEST); #ifdef GSI - if (options.implicit && is_gsi_oid(gss_kex_context->oid)) { - packet_put_cstring(""); + if (options.implicit && is_gsi_oid(gss_kex_context->oid)) { + packet_put_cstring(""); } else { #endif packet_put_cstring(authctxt->server_user); @@ -966,9 +987,11 @@ userauth_passwd(Authctxt *authctxt) return 1; } + /* * 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) { @@ -1033,6 +1056,209 @@ input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt) &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 identity_sign(Identity *id, u_char **sigp, u_int *lenp, u_char *data, u_int datalen) @@ -1607,6 +1833,76 @@ userauth_hostbased(Authctxt *authctxt) 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 */ /* @@ -1708,3 +2004,4 @@ authmethods_get(void) buffer_free(&b); return list; } +