diff options
Diffstat (limited to 'sshconnect2.c')
| -rw-r--r-- | sshconnect2.c | 303 |
1 files changed, 301 insertions, 2 deletions
diff --git a/sshconnect2.c b/sshconnect2.c index 7d0c5e82..a762eec3 100644 --- a/sshconnect2.c +++ b/sshconnect2.c @@ -1,6 +1,7 @@ -/* $OpenBSD: sshconnect2.c,v 1.169 2008/11/01 04:50:08 djm Exp $ */ +/* $OpenBSD: sshconnect2.c,v 1.170 2008/11/04 08:22:13 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 @@ -67,6 +68,7 @@ #include "msg.h" #include "pathnames.h" #include "uidswap.h" +#include "jpake.h" #ifdef GSSAPI #include "ssh-gss.h" @@ -201,6 +203,7 @@ 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 */ }; @@ -212,12 +215,18 @@ 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_gssapi(Authctxt *authctxt); @@ -243,30 +252,43 @@ Authmethod authmethods[] = { #ifdef GSSAPI {"gssapi-with-mic", 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 @@ -334,6 +356,9 @@ 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; @@ -851,6 +876,209 @@ 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) @@ -1425,6 +1653,76 @@ 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 */ /* @@ -1526,3 +1824,4 @@ authmethods_get(void) buffer_free(&b); return list; } + |