=================================================================== RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/ssh/sshconnect2.c,v retrieving revision 1.27.2.3 retrieving revision 1.27.2.4 diff -u -r1.27.2.3 -r1.27.2.4 --- src/usr.bin/ssh/sshconnect2.c 2001/03/21 19:46:31 1.27.2.3 +++ src/usr.bin/ssh/sshconnect2.c 2001/05/07 21:09:37 1.27.2.4 @@ -23,7 +23,7 @@ */ #include "includes.h" -RCSID("$OpenBSD: sshconnect2.c,v 1.27.2.3 2001/03/21 19:46:31 jason Exp $"); +RCSID("$OpenBSD: sshconnect2.c,v 1.27.2.4 2001/05/07 21:09:37 jason Exp $"); #include #include @@ -46,16 +46,15 @@ #include "sshconnect.h" #include "authfile.h" #include "cli.h" -#include "dispatch.h" +#include "dh.h" #include "authfd.h" #include "log.h" #include "readconf.h" #include "readpass.h" #include "match.h" +#include "dispatch.h" +#include "canohost.h" -void ssh_dh1_client(Kex *, char *, struct sockaddr *, Buffer *, Buffer *); -void ssh_dhgex_client(Kex *, char *, struct sockaddr *, Buffer *, Buffer *); - /* import */ extern char *client_version_string; extern char *server_version_string; @@ -68,14 +67,27 @@ u_char *session_id2 = NULL; int session_id2_len = 0; +char *xxx_host; +struct sockaddr *xxx_hostaddr; + +Kex *xxx_kex = NULL; + +int +check_host_key_callback(Key *hostkey) +{ + check_host_key(xxx_host, xxx_hostaddr, hostkey, + options.user_hostfile2, options.system_hostfile2); + return 0; +} + void ssh_kex2(char *host, struct sockaddr *hostaddr) { - int i, plen; Kex *kex; - Buffer *client_kexinit, *server_kexinit; - char *sprop[PROPOSAL_MAX]; + xxx_host = host; + xxx_hostaddr = hostaddr; + if (options.ciphers == (char *)-1) { log("No valid ciphers for protocol version 2 given, using defaults."); options.ciphers = NULL; @@ -84,6 +96,10 @@ 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] = + compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); if (options.compression) { myproposal[PROPOSAL_COMP_ALGS_CTOS] = myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib"; @@ -95,48 +111,23 @@ myproposal[PROPOSAL_MAC_ALGS_CTOS] = myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; } + if (options.hostkeyalgorithms != NULL) + myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = + options.hostkeyalgorithms; - /* buffers with raw kexinit messages */ - server_kexinit = xmalloc(sizeof(*server_kexinit)); - buffer_init(server_kexinit); - client_kexinit = kex_init(myproposal); + /* start key exchange */ + kex = kex_setup(myproposal); + kex->client_version_string=client_version_string; + kex->server_version_string=server_version_string; + kex->check_host_key=&check_host_key_callback; - /* algorithm negotiation */ - kex_exchange_kexinit(client_kexinit, server_kexinit, sprop); - kex = kex_choose_conf(myproposal, sprop, 0); - for (i = 0; i < PROPOSAL_MAX; i++) - xfree(sprop[i]); + xxx_kex = kex; - /* server authentication and session key agreement */ - switch(kex->kex_type) { - case DH_GRP1_SHA1: - ssh_dh1_client(kex, host, hostaddr, - client_kexinit, server_kexinit); - break; - case DH_GEX_SHA1: - ssh_dhgex_client(kex, host, hostaddr, client_kexinit, - server_kexinit); - break; - default: - fatal("Unsupported key exchange %d", kex->kex_type); - } + dispatch_run(DISPATCH_BLOCK, &kex->done, kex); - buffer_free(client_kexinit); - buffer_free(server_kexinit); - xfree(client_kexinit); - xfree(server_kexinit); + session_id2 = kex->session_id; + session_id2_len = kex->session_id_len; - debug("Wait SSH2_MSG_NEWKEYS."); - packet_read_expect(&plen, SSH2_MSG_NEWKEYS); - packet_done(); - debug("GOT SSH2_MSG_NEWKEYS."); - - debug("send SSH2_MSG_NEWKEYS."); - packet_start(SSH2_MSG_NEWKEYS); - packet_send(); - packet_write_wait(); - debug("done: send SSH2_MSG_NEWKEYS."); - #ifdef DEBUG_KEXDH /* send 1st encrypted/maced/compressed message */ packet_start(SSH2_MSG_IGNORE); @@ -144,313 +135,10 @@ packet_send(); packet_write_wait(); #endif - debug("done: KEX2."); + debug("done: ssh_kex2."); } -/* diffie-hellman-group1-sha1 */ - -void -ssh_dh1_client(Kex *kex, char *host, struct sockaddr *hostaddr, - Buffer *client_kexinit, Buffer *server_kexinit) -{ -#ifdef DEBUG_KEXDH - int i; -#endif - int plen, dlen; - u_int klen, kout; - char *signature = NULL; - u_int slen; - char *server_host_key_blob = NULL; - Key *server_host_key; - u_int sbloblen; - DH *dh; - BIGNUM *dh_server_pub = 0; - BIGNUM *shared_secret = 0; - u_char *kbuf; - u_char *hash; - - debug("Sending SSH2_MSG_KEXDH_INIT."); - /* generate and send 'e', client DH public key */ - dh = dh_new_group1(); - dh_gen_key(dh, kex->we_need * 8); - packet_start(SSH2_MSG_KEXDH_INIT); - packet_put_bignum2(dh->pub_key); - packet_send(); - packet_write_wait(); - -#ifdef DEBUG_KEXDH - fprintf(stderr, "\np= "); - BN_print_fp(stderr, dh->p); - fprintf(stderr, "\ng= "); - BN_print_fp(stderr, dh->g); - fprintf(stderr, "\npub= "); - BN_print_fp(stderr, dh->pub_key); - fprintf(stderr, "\n"); - DHparams_print_fp(stderr, dh); -#endif - - debug("Wait SSH2_MSG_KEXDH_REPLY."); - - packet_read_expect(&plen, SSH2_MSG_KEXDH_REPLY); - - debug("Got SSH2_MSG_KEXDH_REPLY."); - - /* key, cert */ - server_host_key_blob = packet_get_string(&sbloblen); - server_host_key = key_from_blob(server_host_key_blob, sbloblen); - if (server_host_key == NULL) - fatal("cannot decode server_host_key_blob"); - - check_host_key(host, hostaddr, server_host_key, - options.user_hostfile2, options.system_hostfile2); - - /* DH paramter f, server public DH key */ - dh_server_pub = BN_new(); - if (dh_server_pub == NULL) - fatal("dh_server_pub == NULL"); - packet_get_bignum2(dh_server_pub, &dlen); - -#ifdef DEBUG_KEXDH - fprintf(stderr, "\ndh_server_pub= "); - BN_print_fp(stderr, dh_server_pub); - fprintf(stderr, "\n"); - debug("bits %d", BN_num_bits(dh_server_pub)); -#endif - - /* signed H */ - signature = packet_get_string(&slen); - packet_done(); - - if (!dh_pub_is_valid(dh, dh_server_pub)) - packet_disconnect("bad server public DH value"); - - klen = DH_size(dh); - kbuf = xmalloc(klen); - kout = DH_compute_key(kbuf, dh_server_pub, dh); -#ifdef DEBUG_KEXDH - debug("shared secret: len %d/%d", klen, kout); - fprintf(stderr, "shared secret == "); - for (i = 0; i< kout; i++) - fprintf(stderr, "%02x", (kbuf[i])&0xff); - fprintf(stderr, "\n"); -#endif - shared_secret = BN_new(); - - BN_bin2bn(kbuf, kout, shared_secret); - memset(kbuf, 0, klen); - xfree(kbuf); - - /* calc and verify H */ - hash = kex_hash( - client_version_string, - server_version_string, - buffer_ptr(client_kexinit), buffer_len(client_kexinit), - buffer_ptr(server_kexinit), buffer_len(server_kexinit), - server_host_key_blob, sbloblen, - dh->pub_key, - dh_server_pub, - shared_secret - ); - xfree(server_host_key_blob); - DH_free(dh); - BN_free(dh_server_pub); -#ifdef DEBUG_KEXDH - fprintf(stderr, "hash == "); - for (i = 0; i< 20; i++) - fprintf(stderr, "%02x", (hash[i])&0xff); - fprintf(stderr, "\n"); -#endif - if (key_verify(server_host_key, (u_char *)signature, slen, hash, 20) != 1) - fatal("key_verify failed for server_host_key"); - key_free(server_host_key); - xfree(signature); - - kex_derive_keys(kex, hash, shared_secret); - BN_clear_free(shared_secret); - packet_set_kex(kex); - - /* save session id */ - session_id2_len = 20; - session_id2 = xmalloc(session_id2_len); - memcpy(session_id2, hash, session_id2_len); -} - -/* diffie-hellman-group-exchange-sha1 */ - /* - * Estimates the group order for a Diffie-Hellman group that has an - * attack complexity approximately the same as O(2**bits). Estimate - * with: O(exp(1.9223 * (ln q)^(1/3) (ln ln q)^(2/3))) - */ - -int -dh_estimate(int bits) -{ - - if (bits < 64) - return (512); /* O(2**63) */ - if (bits < 128) - return (1024); /* O(2**86) */ - if (bits < 192) - return (2048); /* O(2**116) */ - return (4096); /* O(2**156) */ -} - -void -ssh_dhgex_client(Kex *kex, char *host, struct sockaddr *hostaddr, - Buffer *client_kexinit, Buffer *server_kexinit) -{ -#ifdef DEBUG_KEXDH - int i; -#endif - int plen, dlen; - u_int klen, kout; - char *signature = NULL; - u_int slen, nbits; - char *server_host_key_blob = NULL; - Key *server_host_key; - u_int sbloblen; - DH *dh; - BIGNUM *dh_server_pub = 0; - BIGNUM *shared_secret = 0; - BIGNUM *p = 0, *g = 0; - u_char *kbuf; - u_char *hash; - - nbits = dh_estimate(kex->we_need * 8); - - debug("Sending SSH2_MSG_KEX_DH_GEX_REQUEST."); - packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST); - packet_put_int(nbits); - packet_send(); - packet_write_wait(); - -#ifdef DEBUG_KEXDH - fprintf(stderr, "\nnbits = %d", nbits); -#endif - - debug("Wait SSH2_MSG_KEX_DH_GEX_GROUP."); - - packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_GROUP); - - debug("Got SSH2_MSG_KEX_DH_GEX_GROUP."); - - if ((p = BN_new()) == NULL) - fatal("BN_new"); - packet_get_bignum2(p, &dlen); - if ((g = BN_new()) == NULL) - fatal("BN_new"); - packet_get_bignum2(g, &dlen); - dh = dh_new_group(g, p); - - dh_gen_key(dh, kex->we_need * 8); - -#ifdef DEBUG_KEXDH - fprintf(stderr, "\np= "); - BN_print_fp(stderr, dh->p); - fprintf(stderr, "\ng= "); - BN_print_fp(stderr, dh->g); - fprintf(stderr, "\npub= "); - BN_print_fp(stderr, dh->pub_key); - fprintf(stderr, "\n"); - DHparams_print_fp(stderr, dh); -#endif - - debug("Sending SSH2_MSG_KEX_DH_GEX_INIT."); - /* generate and send 'e', client DH public key */ - packet_start(SSH2_MSG_KEX_DH_GEX_INIT); - packet_put_bignum2(dh->pub_key); - packet_send(); - packet_write_wait(); - - debug("Wait SSH2_MSG_KEX_DH_GEX_REPLY."); - - packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_REPLY); - - debug("Got SSH2_MSG_KEXDH_REPLY."); - - /* key, cert */ - server_host_key_blob = packet_get_string(&sbloblen); - server_host_key = key_from_blob(server_host_key_blob, sbloblen); - if (server_host_key == NULL) - fatal("cannot decode server_host_key_blob"); - - check_host_key(host, hostaddr, server_host_key, - options.user_hostfile2, options.system_hostfile2); - - /* DH paramter f, server public DH key */ - dh_server_pub = BN_new(); - if (dh_server_pub == NULL) - fatal("dh_server_pub == NULL"); - packet_get_bignum2(dh_server_pub, &dlen); - -#ifdef DEBUG_KEXDH - fprintf(stderr, "\ndh_server_pub= "); - BN_print_fp(stderr, dh_server_pub); - fprintf(stderr, "\n"); - debug("bits %d", BN_num_bits(dh_server_pub)); -#endif - - /* signed H */ - signature = packet_get_string(&slen); - packet_done(); - - if (!dh_pub_is_valid(dh, dh_server_pub)) - packet_disconnect("bad server public DH value"); - - klen = DH_size(dh); - kbuf = xmalloc(klen); - kout = DH_compute_key(kbuf, dh_server_pub, dh); -#ifdef DEBUG_KEXDH - debug("shared secret: len %d/%d", klen, kout); - fprintf(stderr, "shared secret == "); - for (i = 0; i< kout; i++) - fprintf(stderr, "%02x", (kbuf[i])&0xff); - fprintf(stderr, "\n"); -#endif - shared_secret = BN_new(); - - BN_bin2bn(kbuf, kout, shared_secret); - memset(kbuf, 0, klen); - xfree(kbuf); - - /* calc and verify H */ - hash = kex_hash_gex( - client_version_string, - server_version_string, - buffer_ptr(client_kexinit), buffer_len(client_kexinit), - buffer_ptr(server_kexinit), buffer_len(server_kexinit), - server_host_key_blob, sbloblen, - nbits, dh->p, dh->g, - dh->pub_key, - dh_server_pub, - shared_secret - ); - xfree(server_host_key_blob); - DH_free(dh); - BN_free(dh_server_pub); -#ifdef DEBUG_KEXDH - fprintf(stderr, "hash == "); - for (i = 0; i< 20; i++) - fprintf(stderr, "%02x", (hash[i])&0xff); - fprintf(stderr, "\n"); -#endif - if (key_verify(server_host_key, (u_char *)signature, slen, hash, 20) != 1) - fatal("key_verify failed for server_host_key"); - key_free(server_host_key); - xfree(signature); - - kex_derive_keys(kex, hash, shared_secret); - BN_clear_free(shared_secret); - packet_set_kex(kex); - - /* save session id */ - session_id2_len = 20; - session_id2 = xmalloc(session_id2_len); - memcpy(session_id2, hash, session_id2_len); -} - -/* * Authenticate user */ @@ -463,15 +151,20 @@ struct Authctxt { const char *server_user; + const char *local_user; const char *host; const char *service; - AuthenticationConnection *agent; Authmethod *method; int success; char *authlist; + /* pubkey */ Key *last_key; sign_cb_fn *last_key_sign; int last_key_hint; + AuthenticationConnection *agent; + /* hostbased */ + Key **keys; + int nkeys; }; struct Authmethod { char *name; /* string to compare against server's list */ @@ -491,6 +184,7 @@ int userauth_pubkey(Authctxt *authctxt); int userauth_passwd(Authctxt *authctxt); int userauth_kbdint(Authctxt *authctxt); +int userauth_hostbased(Authctxt *authctxt); void userauth(Authctxt *authctxt, char *authlist); @@ -516,6 +210,10 @@ userauth_kbdint, &options.kbd_interactive_authentication, &options.batch_mode}, + {"hostbased", + userauth_hostbased, + &options.hostbased_authentication, + NULL}, {"none", userauth_none, NULL, @@ -524,7 +222,8 @@ }; void -ssh_userauth2(const char *server_user, char *host) +ssh_userauth2(const char *local_user, const char *server_user, char *host, + Key **keys, int nkeys) { Authctxt authctxt; int type; @@ -558,11 +257,14 @@ /* setup authentication context */ authctxt.agent = ssh_get_authentication_connection(); authctxt.server_user = server_user; + authctxt.local_user = local_user; authctxt.host = host; authctxt.service = "ssh-connection"; /* service name */ authctxt.success = 0; authctxt.method = authmethod_lookup("none"); authctxt.authlist = NULL; + authctxt.keys = keys; + authctxt.nkeys = nkeys; if (authctxt.method == NULL) fatal("ssh_userauth2: internal error: cannot send userauth none request"); @@ -659,7 +361,7 @@ Authctxt *authctxt = ctxt; Key *key = NULL; Buffer b; - int alen, blen, pktype, sent = 0; + int alen, blen, sent = 0; char *pkalg, *pkblob, *fp; if (authctxt == NULL) @@ -687,7 +389,7 @@ debug("no last key or no sign cb"); break; } - if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { + if (key_type_from_name(pkalg) == KEY_UNSPEC) { debug("unknown pkalg %s", pkalg); break; } @@ -898,26 +600,24 @@ { Key *private; char prompt[300], *passphrase; - int success = 0, quit, i; + int quit, i; struct stat st; if (stat(filename, &st) < 0) { debug3("no such identity: %s", filename); return NULL; } - private = key_new(KEY_UNSPEC); - if (!load_private_key(filename, "", private, NULL)) { - if (options.batch_mode) { - key_free(private); + private = key_load_private_type(KEY_UNSPEC, filename, "", NULL); + if (private == NULL) { + if (options.batch_mode) return NULL; - } snprintf(prompt, sizeof prompt, "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) { - success = load_private_key(filename, - passphrase, private, NULL); + private = key_load_private_type(KEY_UNSPEC, filename, + passphrase, NULL); quit = 0; } else { debug2("no passphrase given, try next key"); @@ -925,14 +625,10 @@ } memset(passphrase, 0, strlen(passphrase)); xfree(passphrase); - if (success || quit) + if (private != NULL || quit) break; debug2("bad passphrase given, try again..."); } - if (!success) { - key_free(private); - return NULL; - } } return private; } @@ -964,7 +660,7 @@ int key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, u_char *data, int datalen) { - return key_sign(key, sigp, lenp, data, datalen); + return key_sign(key, sigp, lenp, data, datalen); } int @@ -1108,6 +804,95 @@ 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. + */ +int +userauth_hostbased(Authctxt *authctxt) +{ + Key *private = NULL; + Buffer b; + u_char *signature, *blob; + char *chost, *pkalg, *p; + const char *service; + u_int blen, slen; + int ok, i, len, found = 0; + + p = get_local_name(packet_get_connection_in()); + if (p == NULL) { + error("userauth_hostbased: cannot get local ipaddr/name"); + return 0; + } + len = strlen(p) + 2; + chost = xmalloc(len); + strlcpy(chost, p, len); + strlcat(chost, ".", len); + debug2("userauth_hostbased: chost %s", chost); + /* check for a useful key */ + for (i = 0; i < authctxt->nkeys; i++) { + private = authctxt->keys[i]; + if (private && private->type != KEY_RSA1) { + found = 1; + /* we take and free the key */ + authctxt->keys[i] = NULL; + break; + } + } + if (!found) { + xfree(chost); + return 0; + } + if (key_to_blob(private, &blob, &blen) == 0) { + key_free(private); + xfree(chost); + return 0; + } + service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : + authctxt->service; + pkalg = xstrdup(key_ssh_name(private)); + buffer_init(&b); + /* construct data */ + buffer_put_string(&b, session_id2, session_id2_len); + buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); + buffer_put_cstring(&b, authctxt->server_user); + buffer_put_cstring(&b, service); + buffer_put_cstring(&b, authctxt->method->name); + buffer_put_cstring(&b, pkalg); + buffer_put_string(&b, blob, blen); + buffer_put_cstring(&b, chost); + buffer_put_cstring(&b, authctxt->local_user); +#ifdef DEBUG_PK + buffer_dump(&b); +#endif + debug2("xxx: chost %s", chost); + 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); + return 0; + } + 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_cstring(pkalg); + packet_put_string(blob, blen); + packet_put_cstring(chost); + packet_put_cstring(authctxt->local_user); + packet_put_string(signature, slen); + memset(signature, 's', slen); + xfree(signature); + xfree(chost); + xfree(pkalg); + + packet_send(); + return 1; +} + /* find auth method */ /* @@ -1147,7 +932,7 @@ /* * Given the authentication method list sent by the server, return the * next method we should try. If the server initially sends a nil list, - * use a built-in default list. + * use a built-in default list. */ Authmethod * authmethod_get(char *authlist)