]> andersk Git - gssapi-openssh.git/blobdiff - openssh/sshconnect2.c
drop support for old external-keyx and gssapi methods
[gssapi-openssh.git] / openssh / sshconnect2.c
index 389bec9e43b47dcf9eb9e12f4ff3a692e3941fe1..c4136d532e3ee2cfc7b447eb7feb47e7405dedbe 100644 (file)
@@ -1,6 +1,7 @@
-/* $OpenBSD: sshconnect2.c,v 1.166 2008/07/17 08:48:00 djm 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
@@ -67,6 +68,8 @@
 #include "msg.h"
 #include "pathnames.h"
 #include "uidswap.h"
+#include "schnorr.h"
+#include "jpake.h"
 
 #ifdef GSSAPI
 #include "ssh-gss.h"
 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
@@ -102,9 +121,34 @@ 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
+       if (options.gss_keyex) {
+               /* Add the GSSAPI mechanisms currently supported on this 
+                * client to the key exchange algorithm proposal */
+               orig = myproposal[PROPOSAL_KEX_ALGS];
+
+               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) {
+                       debug("Offering GSSAPI proposal: %s", gss);
+                       xasprintf(&myproposal[PROPOSAL_KEX_ALGS],
+                           "%s,%s", gss, orig);
+               }
+       }
+#endif
+
        if (options.ciphers == (char *)-1) {
                logit("No valid ciphers for protocol version 2 given, using defaults.");
                options.ciphers = NULL;
@@ -132,6 +176,17 @@ ssh_kex2(char *host, struct sockaddr *hostaddr)
                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);
 
@@ -141,10 +196,26 @@ ssh_kex2(char *host, struct sockaddr *hostaddr)
        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;
 
+#ifdef GSSAPI
+       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;
 
        dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
@@ -201,6 +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 */
 };
@@ -212,13 +284,18 @@ 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_kerberos(Authctxt *);
+int    userauth_jpake(Authctxt *);
+
+void   userauth_jpake_cleanup(Authctxt *);
 
 #ifdef GSSAPI
 int    userauth_gssapi(Authctxt *authctxt);
@@ -227,6 +304,7 @@ 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 *, char *);
@@ -242,32 +320,50 @@ static char *authmethods_get(void);
 
 Authmethod authmethods[] = {
 #ifdef GSSAPI
+       {"gssapi-keyex",
+               userauth_gsskeyex,
+               NULL,
+               &options.gss_authentication,
+               NULL},
        {"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
@@ -329,12 +425,37 @@ ssh_userauth2(const char *local_user, const char *server_user, char *host,
        pubkey_cleanup(&authctxt);
        dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL);
 
+       /* 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->method != NULL && authctxt->method->cleanup != NULL)
+               authctxt->method->cleanup(authctxt);
+
        if (authctxt->methoddata) {
                xfree(authctxt->methoddata);
                authctxt->methoddata = NULL;
@@ -367,6 +488,7 @@ userauth(Authctxt *authctxt, char *authlist)
        }
 }
 
+/* ARGSUSED */
 void
 input_userauth_error(int type, u_int32_t seq, void *ctxt)
 {
@@ -374,6 +496,7 @@ 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)
 {
@@ -383,11 +506,11 @@ input_userauth_banner(int type, u_int32_t seq, void *ctxt)
        debug3("input_userauth_banner");
        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); /* max expansion from strnvis() */
-               strnvis(msg, raw, len * 4, VIS_SAFE|VIS_OCTAL);
+               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);
        }
@@ -395,6 +518,7 @@ input_userauth_banner(int type, u_int32_t seq, void *ctxt)
        xfree(lang);
 }
 
+/* ARGSUSED */
 void
 input_userauth_success(int type, u_int32_t seq, void *ctxt)
 {
@@ -412,6 +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)
 {
@@ -432,6 +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)
 {
@@ -511,19 +638,34 @@ userauth_gssapi(Authctxt *authctxt)
        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;
+       }
+
+       if (options.gss_trust_dns)
+               gss_host = (char *)get_canonical_hostname(1);
+       else
+               gss_host = (char *)authctxt->host;
 
        /* Try one GSSAPI method at a time, rather than sending them all at
         * 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], authctxt->host)) {
+                   &gss_supported->elements[mech], gss_host, 
+                    options.gss_client_identity)) {
                        ok = 1; /* Mechanism works */
                } else {
                        mech++;
@@ -587,7 +729,8 @@ process_gssapi_token(void *ctxt, gss_buffer_t recv_tok)
 
        if (status == GSS_S_COMPLETE) {
                /* send either complete or MIC, depending on mechanism */
-               if (!(flags & GSS_C_INTEG_FLAG)) {
+               if (strcmp(authctxt->method->name,"gssapi")==0 ||
+                   (!(flags & GSS_C_INTEG_FLAG))) {
                        packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
                        packet_send();
                } else {
@@ -614,13 +757,14 @@ 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)
 {
        Authctxt *authctxt = ctxt;
        Gssctxt *gssctxt;
-       int oidlen;
-       char *oidv;
+       u_int oidlen;
+       u_char *oidv;
 
        if (authctxt == NULL)
                fatal("input_gssapi_response: no authentication context");
@@ -653,6 +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)
 {
@@ -680,6 +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)
 {
@@ -709,6 +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)
 {
@@ -727,6 +874,73 @@ input_gssapi_error(int type, u_int32_t plen, void *ctxt)
        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_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
@@ -773,9 +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)
 {
@@ -840,6 +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)
@@ -1414,6 +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 */
 
 /*
@@ -1515,3 +2004,4 @@ authmethods_get(void)
        buffer_free(&b);
        return list;
 }
+
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