From 01ed2272a1545336173bf3aef66fbccc3494c8d8 Mon Sep 17 00:00:00 2001 From: Damien Miller Date: Wed, 5 Nov 2008 16:20:46 +1100 Subject: - djm@cvs.openbsd.org 2008/11/04 08:22:13 [auth.h auth2.c monitor.c monitor.h monitor_wrap.c monitor_wrap.h] [readconf.c readconf.h servconf.c servconf.h ssh2.h ssh_config.5] [sshconnect2.c sshd_config.5 jpake.c jpake.h schnorr.c auth2-jpake.c] [Makefile.in] Add support for an experimental zero-knowledge password authentication method using the J-PAKE protocol described in F. Hao, P. Ryan, "Password Authenticated Key Exchange by Juggling", 16th Workshop on Security Protocols, Cambridge, April 2008. This method allows password-based authentication without exposing the password to the server. Instead, the client and server exchange cryptographic proofs to demonstrate of knowledge of the password while revealing nothing useful to an attacker or compromised endpoint. This is experimental, work-in-progress code and is presently compiled-time disabled (turn on -DJPAKE in Makefile.inc). "just commit it. It isn't too intrusive." deraadt@ --- monitor.c | 227 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 226 insertions(+), 1 deletion(-) (limited to 'monitor.c') diff --git a/monitor.c b/monitor.c index 73cf6bc9b..39deedc8f 100644 --- a/monitor.c +++ b/monitor.c @@ -1,4 +1,4 @@ -/* $OpenBSD: monitor.c,v 1.99 2008/07/10 18:08:11 markus Exp $ */ +/* $OpenBSD: monitor.c,v 1.100 2008/11/04 08:22:13 djm Exp $ */ /* * Copyright 2002 Niels Provos * Copyright 2002 Markus Friedl @@ -87,6 +87,7 @@ #include "misc.h" #include "compat.h" #include "ssh2.h" +#include "jpake.h" #ifdef GSSAPI static Gssctxt *gsscontext = NULL; @@ -149,6 +150,11 @@ int mm_answer_rsa_challenge(int, Buffer *); int mm_answer_rsa_response(int, Buffer *); int mm_answer_sesskey(int, Buffer *); int mm_answer_sessid(int, Buffer *); +int mm_answer_jpake_get_pwdata(int, Buffer *); +int mm_answer_jpake_step1(int, Buffer *); +int mm_answer_jpake_step2(int, Buffer *); +int mm_answer_jpake_key_confirm(int, Buffer *); +int mm_answer_jpake_check_confirm(int, Buffer *); #ifdef USE_PAM int mm_answer_pam_start(int, Buffer *); @@ -233,6 +239,13 @@ struct mon_table mon_dispatch_proto20[] = { {MONITOR_REQ_GSSSTEP, MON_ISAUTH, mm_answer_gss_accept_ctx}, {MONITOR_REQ_GSSUSEROK, MON_AUTH, mm_answer_gss_userok}, {MONITOR_REQ_GSSCHECKMIC, MON_ISAUTH, mm_answer_gss_checkmic}, +#endif +#ifdef JPAKE + {MONITOR_REQ_JPAKE_GET_PWDATA, MON_ONCE, mm_answer_jpake_get_pwdata}, + {MONITOR_REQ_JPAKE_STEP1, MON_ISAUTH, mm_answer_jpake_step1}, + {MONITOR_REQ_JPAKE_STEP2, MON_ONCE, mm_answer_jpake_step2}, + {MONITOR_REQ_JPAKE_KEY_CONFIRM, MON_ONCE, mm_answer_jpake_key_confirm}, + {MONITOR_REQ_JPAKE_CHECK_CONFIRM, MON_AUTH, mm_answer_jpake_check_confirm}, #endif {0, 0, NULL} }; @@ -379,6 +392,15 @@ monitor_child_preauth(Authctxt *_authctxt, struct monitor *pmonitor) if (!authenticated) authctxt->failures++; } +#ifdef JPAKE + /* Cleanup JPAKE context after authentication */ + if (ent->flags & MON_AUTHDECIDE) { + if (authctxt->jpake_ctx != NULL) { + jpake_free(authctxt->jpake_ctx); + authctxt->jpake_ctx = NULL; + } + } +#endif } if (!authctxt->valid) @@ -1969,3 +1991,206 @@ mm_answer_gss_userok(int sock, Buffer *m) return (authenticated); } #endif /* GSSAPI */ + +#ifdef JPAKE +int +mm_answer_jpake_step1(int sock, Buffer *m) +{ + struct jpake_ctx *pctx; + u_char *x3_proof, *x4_proof; + u_int x3_proof_len, x4_proof_len; + + if (!options.zero_knowledge_password_authentication) + fatal("zero_knowledge_password_authentication disabled"); + + if (authctxt->jpake_ctx != NULL) + fatal("%s: authctxt->jpake_ctx already set (%p)", + __func__, authctxt->jpake_ctx); + authctxt->jpake_ctx = pctx = jpake_new(); + + jpake_step1(pctx->grp, + &pctx->server_id, &pctx->server_id_len, + &pctx->x3, &pctx->x4, &pctx->g_x3, &pctx->g_x4, + &x3_proof, &x3_proof_len, + &x4_proof, &x4_proof_len); + + JPAKE_DEBUG_CTX((pctx, "step1 done in %s", __func__)); + + buffer_clear(m); + + buffer_put_string(m, pctx->server_id, pctx->server_id_len); + buffer_put_bignum2(m, pctx->g_x3); + buffer_put_bignum2(m, pctx->g_x4); + buffer_put_string(m, x3_proof, x3_proof_len); + buffer_put_string(m, x4_proof, x4_proof_len); + + debug3("%s: sending step1", __func__); + mm_request_send(sock, MONITOR_ANS_JPAKE_STEP1, m); + + bzero(x3_proof, x3_proof_len); + bzero(x4_proof, x4_proof_len); + xfree(x3_proof); + xfree(x4_proof); + + monitor_permit(mon_dispatch, MONITOR_REQ_JPAKE_GET_PWDATA, 1); + monitor_permit(mon_dispatch, MONITOR_REQ_JPAKE_STEP1, 0); + + return 0; +} + +int +mm_answer_jpake_get_pwdata(int sock, Buffer *m) +{ + struct jpake_ctx *pctx = authctxt->jpake_ctx; + char *hash_scheme, *salt; + + if (pctx == NULL) + fatal("%s: pctx == NULL", __func__); + + auth2_jpake_get_pwdata(authctxt, &pctx->s, &hash_scheme, &salt); + + buffer_clear(m); + /* pctx->s is sensitive, not returned to slave */ + buffer_put_cstring(m, hash_scheme); + buffer_put_cstring(m, salt); + + debug3("%s: sending pwdata", __func__); + mm_request_send(sock, MONITOR_ANS_JPAKE_GET_PWDATA, m); + + bzero(hash_scheme, strlen(hash_scheme)); + bzero(salt, strlen(salt)); + xfree(hash_scheme); + xfree(salt); + + monitor_permit(mon_dispatch, MONITOR_REQ_JPAKE_STEP2, 1); + + return 0; +} + +int +mm_answer_jpake_step2(int sock, Buffer *m) +{ + struct jpake_ctx *pctx = authctxt->jpake_ctx; + u_char *x1_proof, *x2_proof, *x4_s_proof; + u_int x1_proof_len, x2_proof_len, x4_s_proof_len; + + if (pctx == NULL) + fatal("%s: pctx == NULL", __func__); + + if ((pctx->g_x1 = BN_new()) == NULL || + (pctx->g_x2 = BN_new()) == NULL) + fatal("%s: BN_new", __func__); + buffer_get_bignum2(m, pctx->g_x1); + buffer_get_bignum2(m, pctx->g_x2); + pctx->client_id = buffer_get_string(m, &pctx->client_id_len); + x1_proof = buffer_get_string(m, &x1_proof_len); + x2_proof = buffer_get_string(m, &x2_proof_len); + + jpake_step2(pctx->grp, pctx->s, pctx->g_x3, + pctx->g_x1, pctx->g_x2, pctx->x4, + pctx->client_id, pctx->client_id_len, + pctx->server_id, pctx->server_id_len, + x1_proof, x1_proof_len, + x2_proof, x2_proof_len, + &pctx->b, + &x4_s_proof, &x4_s_proof_len); + + JPAKE_DEBUG_CTX((pctx, "step2 done in %s", __func__)); + + bzero(x1_proof, x1_proof_len); + bzero(x2_proof, x2_proof_len); + xfree(x1_proof); + xfree(x2_proof); + + buffer_clear(m); + + buffer_put_bignum2(m, pctx->b); + buffer_put_string(m, x4_s_proof, x4_s_proof_len); + + debug3("%s: sending step2", __func__); + mm_request_send(sock, MONITOR_ANS_JPAKE_STEP2, m); + + bzero(x4_s_proof, x4_s_proof_len); + xfree(x4_s_proof); + + monitor_permit(mon_dispatch, MONITOR_REQ_JPAKE_KEY_CONFIRM, 1); + + return 0; +} + +int +mm_answer_jpake_key_confirm(int sock, Buffer *m) +{ + struct jpake_ctx *pctx = authctxt->jpake_ctx; + u_char *x2_s_proof; + u_int x2_s_proof_len; + + if (pctx == NULL) + fatal("%s: pctx == NULL", __func__); + + if ((pctx->a = BN_new()) == NULL) + fatal("%s: BN_new", __func__); + buffer_get_bignum2(m, pctx->a); + x2_s_proof = buffer_get_string(m, &x2_s_proof_len); + + jpake_key_confirm(pctx->grp, pctx->s, pctx->a, + pctx->x4, pctx->g_x3, pctx->g_x4, pctx->g_x1, pctx->g_x2, + pctx->server_id, pctx->server_id_len, + pctx->client_id, pctx->client_id_len, + session_id2, session_id2_len, + x2_s_proof, x2_s_proof_len, + &pctx->k, + &pctx->h_k_sid_sessid, &pctx->h_k_sid_sessid_len); + + JPAKE_DEBUG_CTX((pctx, "key_confirm done in %s", __func__)); + + bzero(x2_s_proof, x2_s_proof_len); + buffer_clear(m); + + /* pctx->k is sensitive, not sent */ + buffer_put_string(m, pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len); + + debug3("%s: sending confirmation hash", __func__); + mm_request_send(sock, MONITOR_ANS_JPAKE_KEY_CONFIRM, m); + + monitor_permit(mon_dispatch, MONITOR_REQ_JPAKE_CHECK_CONFIRM, 1); + + return 0; +} + +int +mm_answer_jpake_check_confirm(int sock, Buffer *m) +{ + int authenticated = 0; + u_char *peer_confirm_hash; + u_int peer_confirm_hash_len; + struct jpake_ctx *pctx = authctxt->jpake_ctx; + + if (pctx == NULL) + fatal("%s: pctx == NULL", __func__); + + peer_confirm_hash = buffer_get_string(m, &peer_confirm_hash_len); + + authenticated = jpake_check_confirm(pctx->k, + pctx->client_id, pctx->client_id_len, + session_id2, session_id2_len, + peer_confirm_hash, peer_confirm_hash_len) && authctxt->valid; + + JPAKE_DEBUG_CTX((pctx, "check_confirm done in %s", __func__)); + + bzero(peer_confirm_hash, peer_confirm_hash_len); + xfree(peer_confirm_hash); + + buffer_clear(m); + buffer_put_int(m, authenticated); + + debug3("%s: sending result %d", __func__, authenticated); + mm_request_send(sock, MONITOR_ANS_JPAKE_CHECK_CONFIRM, m); + + monitor_permit(mon_dispatch, MONITOR_REQ_JPAKE_STEP1, 1); + + auth_method = "jpake-01@openssh.com"; + return authenticated; +} + +#endif /* JPAKE */ -- cgit v1.2.3 From 923e8bb7dc921b3136320f126976bfeee11c9e41 Mon Sep 17 00:00:00 2001 From: Damien Miller Date: Sat, 14 Feb 2009 16:33:31 +1100 Subject: - djm@cvs.openbsd.org 2009/02/12 03:26:22 [monitor.c] some paranoia: check that the serialised key is really KEY_RSA before diddling its internals --- ChangeLog | 6 +++++- monitor.c | 6 ++++-- 2 files changed, 9 insertions(+), 3 deletions(-) (limited to 'monitor.c') diff --git a/ChangeLog b/ChangeLog index e296e0441..5e9a177d9 100644 --- a/ChangeLog +++ b/ChangeLog @@ -14,6 +14,10 @@ [serverloop.c] tighten check for -R0:... forwarding: only allow dynamic allocation if want_reply is set in the packet + - djm@cvs.openbsd.org 2009/02/12 03:26:22 + [monitor.c] + some paranoia: check that the serialised key is really KEY_RSA before + diddling its internals 20090212 - (djm) [sshpty.c] bz#1419: OSX uses cloning ptys that automagically @@ -5140,5 +5144,5 @@ OpenServer 6 and add osr5bigcrypt support so when someone migrates passwords between UnixWare and OpenServer they will still work. OK dtucker@ -$Id: ChangeLog,v 1.5188 2009/02/14 05:33:09 djm Exp $ +$Id: ChangeLog,v 1.5189 2009/02/14 05:33:31 djm Exp $ diff --git a/monitor.c b/monitor.c index 39deedc8f..f57e74ba5 100644 --- a/monitor.c +++ b/monitor.c @@ -1,4 +1,4 @@ -/* $OpenBSD: monitor.c,v 1.100 2008/11/04 08:22:13 djm Exp $ */ +/* $OpenBSD: monitor.c,v 1.101 2009/02/12 03:26:22 djm Exp $ */ /* * Copyright 2002 Niels Provos * Copyright 2002 Markus Friedl @@ -1500,7 +1500,9 @@ mm_answer_rsa_challenge(int sock, Buffer *m) fatal("%s: key type mismatch", __func__); if ((key = key_from_blob(blob, blen)) == NULL) fatal("%s: received bad key", __func__); - + if (key->type != KEY_RSA) + fatal("%s: received bad key type %d", __func__, key->type); + key->type = KEY_RSA1; if (ssh1_challenge) BN_clear_free(ssh1_challenge); ssh1_challenge = auth_rsa_generate_challenge(key); -- cgit v1.2.3