diff options
Diffstat (limited to 'crypto/openssh/sshconnect2.c')
| -rw-r--r-- | crypto/openssh/sshconnect2.c | 1030 |
1 files changed, 0 insertions, 1030 deletions
diff --git a/crypto/openssh/sshconnect2.c b/crypto/openssh/sshconnect2.c deleted file mode 100644 index fb7bff0654b3..000000000000 --- a/crypto/openssh/sshconnect2.c +++ /dev/null @@ -1,1030 +0,0 @@ -/* - * Copyright (c) 2000 Markus Friedl. All rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * - * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR - * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES - * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. - * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, - * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT - * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, - * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY - * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT - * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF - * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. - */ - -#include "includes.h" -RCSID("$FreeBSD$"); -RCSID("$OpenBSD: sshconnect2.c,v 1.27 2000/10/19 16:45:16 provos Exp $"); - -#include <openssl/bn.h> -#include <openssl/rsa.h> -#include <openssl/dsa.h> -#include <openssl/md5.h> -#include <openssl/dh.h> -#include <openssl/hmac.h> - -#include "ssh.h" -#include "xmalloc.h" -#include "rsa.h" -#include "buffer.h" -#include "packet.h" -#include "uidswap.h" -#include "compat.h" -#include "readconf.h" -#include "bufaux.h" -#include "ssh2.h" -#include "kex.h" -#include "myproposal.h" -#include "key.h" -#include "dsa.h" -#include "sshconnect.h" -#include "authfile.h" -#include "cli.h" -#include "dispatch.h" -#include "authfd.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; -extern Options options; - -/* - * SSH2 key exchange - */ - -unsigned char *session_id2 = NULL; -int session_id2_len = 0; - -void -ssh_kex2(char *host, struct sockaddr *hostaddr) -{ - int i, plen; - Kex *kex; - Buffer *client_kexinit, *server_kexinit; - char *sprop[PROPOSAL_MAX]; - - if (options.ciphers == NULL) { - if (options.cipher == SSH_CIPHER_3DES) { - options.ciphers = "3des-cbc"; - } else if (options.cipher == SSH_CIPHER_BLOWFISH) { - options.ciphers = "blowfish-cbc"; - } else if (options.cipher == SSH_CIPHER_DES) { - fatal("cipher DES not supported for protocol version 2"); - } - } - if (options.ciphers != NULL) { - myproposal[PROPOSAL_ENC_ALGS_CTOS] = - myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; - } - if (options.compression) { - myproposal[PROPOSAL_COMP_ALGS_CTOS] = "zlib"; - myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib"; - } else { - myproposal[PROPOSAL_COMP_ALGS_CTOS] = "none"; - myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; - } - - /* buffers with raw kexinit messages */ - server_kexinit = xmalloc(sizeof(*server_kexinit)); - buffer_init(server_kexinit); - client_kexinit = kex_init(myproposal); - - /* 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]); - - /* 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); - } - - buffer_free(client_kexinit); - buffer_free(server_kexinit); - xfree(client_kexinit); - xfree(server_kexinit); - - 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); - packet_put_cstring("markus"); - packet_send(); - packet_write_wait(); -#endif - debug("done: 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; - unsigned int klen, kout; - char *signature = NULL; - unsigned int slen; - char *server_host_key_blob = NULL; - Key *server_host_key; - unsigned int sbloblen; - DH *dh; - BIGNUM *dh_server_pub = 0; - BIGNUM *shared_secret = 0; - unsigned char *kbuf; - unsigned char *hash; - - debug("Sending SSH2_MSG_KEXDH_INIT."); - /* generate and send 'e', client DH public key */ - dh = dh_new_group1(); - 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 = dsa_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); -#ifdef DEBUG_KEXDH - fprintf(stderr, "hash == "); - for (i = 0; i< 20; i++) - fprintf(stderr, "%02x", (hash[i])&0xff); - fprintf(stderr, "\n"); -#endif - if (dsa_verify(server_host_key, (unsigned char *)signature, slen, hash, 20) != 1) - fatal("dsa_verify failed for server_host_key"); - key_free(server_host_key); - - kex_derive_keys(kex, hash, 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; - unsigned int klen, kout; - char *signature = NULL; - unsigned int slen, nbits; - char *server_host_key_blob = NULL; - Key *server_host_key; - unsigned int sbloblen; - DH *dh; - BIGNUM *dh_server_pub = 0; - BIGNUM *shared_secret = 0; - BIGNUM *p = 0, *g = 0; - unsigned char *kbuf; - unsigned char *hash; - - nbits = dh_estimate(kex->enc[MODE_OUT].cipher->key_len * 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); - if ((dh = dh_new_group(g, p)) == NULL) - fatal("dh_new_group"); - -#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 = dsa_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); -#ifdef DEBUG_KEXDH - fprintf(stderr, "hash == "); - for (i = 0; i< 20; i++) - fprintf(stderr, "%02x", (hash[i])&0xff); - fprintf(stderr, "\n"); -#endif - if (dsa_verify(server_host_key, (unsigned char *)signature, slen, hash, 20) != 1) - fatal("dsa_verify failed for server_host_key"); - key_free(server_host_key); - - kex_derive_keys(kex, hash, 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 - */ - -typedef struct Authctxt Authctxt; -typedef struct Authmethod Authmethod; - -typedef int sign_cb_fn( - Authctxt *authctxt, Key *key, - unsigned char **sigp, int *lenp, unsigned char *data, int datalen); - -struct Authctxt { - const char *server_user; - const char *host; - const char *service; - AuthenticationConnection *agent; - Authmethod *method; - int success; -}; -struct Authmethod { - char *name; /* string to compare against server's list */ - int (*userauth)(Authctxt *authctxt); - int *enabled; /* flag in option struct that enables method */ - int *batch_flag; /* flag in option struct that disables method */ -}; - -void input_userauth_success(int type, int plen, void *ctxt); -void input_userauth_failure(int type, int plen, void *ctxt); -void input_userauth_error(int type, int plen, void *ctxt); -void input_userauth_info_req(int type, int plen, void *ctxt); - -int userauth_none(Authctxt *authctxt); -int userauth_pubkey(Authctxt *authctxt); -int userauth_passwd(Authctxt *authctxt); -int userauth_kbdint(Authctxt *authctxt); - -void authmethod_clear(); -Authmethod *authmethod_get(char *authlist); -Authmethod *authmethod_lookup(const char *name); - -Authmethod authmethods[] = { - {"publickey", - userauth_pubkey, - &options.dsa_authentication, - NULL}, - {"password", - userauth_passwd, - &options.password_authentication, - &options.batch_mode}, - {"keyboard-interactive", - userauth_kbdint, - &options.kbd_interactive_authentication, - &options.batch_mode}, - {"none", - userauth_none, - NULL, - NULL}, - {NULL, NULL, NULL, NULL} -}; - -void -ssh_userauth2(const char *server_user, char *host) -{ - Authctxt authctxt; - int type; - int plen; - - debug("send SSH2_MSG_SERVICE_REQUEST"); - packet_start(SSH2_MSG_SERVICE_REQUEST); - packet_put_cstring("ssh-userauth"); - packet_send(); - packet_write_wait(); - type = packet_read(&plen); - if (type != SSH2_MSG_SERVICE_ACCEPT) { - fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type); - } - if (packet_remaining() > 0) { - char *reply = packet_get_string(&plen); - debug("service_accept: %s", reply); - xfree(reply); - packet_done(); - } else { - debug("buggy server: service_accept w/o service"); - } - packet_done(); - debug("got SSH2_MSG_SERVICE_ACCEPT"); - - /* setup authentication context */ - authctxt.agent = ssh_get_authentication_connection(); - authctxt.server_user = server_user; - authctxt.host = host; - authctxt.service = "ssh-connection"; /* service name */ - authctxt.success = 0; - authctxt.method = authmethod_lookup("none"); - if (authctxt.method == NULL) - fatal("ssh_userauth2: internal error: cannot send userauth none request"); - authmethod_clear(); - - /* initial userauth request */ - userauth_none(&authctxt); - - dispatch_init(&input_userauth_error); - dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); - dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); - dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ - - if (authctxt.agent != NULL) - ssh_close_authentication_connection(authctxt.agent); - - debug("ssh-userauth2 successfull: method %s", authctxt.method->name); -} -void -input_userauth_error(int type, int plen, void *ctxt) -{ - fatal("input_userauth_error: bad message during authentication"); -} -void -input_userauth_success(int type, int plen, void *ctxt) -{ - Authctxt *authctxt = ctxt; - if (authctxt == NULL) - fatal("input_userauth_success: no authentication context"); - authctxt->success = 1; /* break out */ -} -void -input_userauth_failure(int type, int plen, void *ctxt) -{ - Authmethod *method = NULL; - Authctxt *authctxt = ctxt; - char *authlist = NULL; - int partial; - - if (authctxt == NULL) - fatal("input_userauth_failure: no authentication context"); - - authlist = packet_get_string(NULL); - partial = packet_get_char(); - packet_done(); - - if (partial != 0) - debug("partial success"); - debug("authentications that can continue: %s", authlist); - - for (;;) { - method = authmethod_get(authlist); - if (method == NULL) - fatal("Unable to find an authentication method"); - authctxt->method = method; - if (method->userauth(authctxt) != 0) { - debug2("we sent a %s packet, wait for reply", method->name); - break; - } else { - debug2("we did not send a packet, disable method"); - method->enabled = NULL; - } - } - xfree(authlist); -} - -int -userauth_none(Authctxt *authctxt) -{ - /* initial userauth request */ - 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(); - return 1; -} - -int -userauth_passwd(Authctxt *authctxt) -{ - static int attempt = 0; - char prompt[80]; - char *password; - - if (attempt++ >= options.number_of_password_prompts) - return 0; - - if(attempt != 1) - error("Permission denied, please try again."); - - snprintf(prompt, sizeof(prompt), "%.30s@%.40s's password: ", - authctxt->server_user, authctxt->host); - password = read_passphrase(prompt, 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_char(0); - ssh_put_password(password); - memset(password, 0, strlen(password)); - xfree(password); - packet_send(); - packet_write_wait(); - return 1; -} - -int -sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback) -{ - Buffer b; - unsigned char *blob, *signature; - int bloblen, slen; - int skip = 0; - int ret = -1; - int have_sig = 1; - - dsa_make_key_blob(k, &blob, &bloblen); - - /* data to be signed */ - buffer_init(&b); - if (datafellows & SSH_OLD_SESSIONID) { - buffer_append(&b, session_id2, session_id2_len); - skip = session_id2_len; - } else { - buffer_put_string(&b, session_id2, session_id2_len); - skip = buffer_len(&b); - } - buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); - buffer_put_cstring(&b, authctxt->server_user); - buffer_put_cstring(&b, - datafellows & SSH_BUG_PUBKEYAUTH ? - "ssh-userauth" : - authctxt->service); - buffer_put_cstring(&b, authctxt->method->name); - buffer_put_char(&b, have_sig); - buffer_put_cstring(&b, KEX_DSS); - buffer_put_string(&b, blob, bloblen); - - /* generate signature */ - ret = (*sign_callback)(authctxt, k, &signature, &slen, buffer_ptr(&b), buffer_len(&b)); - if (ret == -1) { - xfree(blob); - buffer_free(&b); - return 0; - } -#ifdef DEBUG_DSS - buffer_dump(&b); -#endif - if (datafellows & SSH_BUG_PUBKEYAUTH) { - buffer_clear(&b); - buffer_append(&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, authctxt->service); - buffer_put_cstring(&b, authctxt->method->name); - buffer_put_char(&b, have_sig); - buffer_put_cstring(&b, KEX_DSS); - buffer_put_string(&b, blob, bloblen); - } - xfree(blob); - /* append signature */ - buffer_put_string(&b, signature, slen); - xfree(signature); - - /* skip session id and packet type */ - if (buffer_len(&b) < skip + 1) - fatal("userauth_pubkey: internal error"); - buffer_consume(&b, skip + 1); - - /* put remaining data from buffer into packet */ - packet_start(SSH2_MSG_USERAUTH_REQUEST); - packet_put_raw(buffer_ptr(&b), buffer_len(&b)); - buffer_free(&b); - - /* send */ - packet_send(); - packet_write_wait(); - - return 1; -} - -/* sign callback */ -int dsa_sign_cb(Authctxt *authctxt, Key *key, unsigned char **sigp, int *lenp, - unsigned char *data, int datalen) -{ - return dsa_sign(key, sigp, lenp, data, datalen); -} - -int -userauth_pubkey_identity(Authctxt *authctxt, char *filename) -{ - Key *k; - int i, ret, try_next; - struct stat st; - - if (stat(filename, &st) != 0) { - debug("key does not exist: %s", filename); - return 0; - } - debug("try pubkey: %s", filename); - - k = key_new(KEY_DSA); - if (!load_private_key(filename, "", k, NULL)) { - int success = 0; - char *passphrase; - char prompt[300]; - snprintf(prompt, sizeof prompt, - "Enter passphrase for %s key '%.100s': ", - key_type(k), 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, k, NULL); - try_next = 0; - } else { - debug2("no passphrase given, try next key"); - try_next = 1; - } - memset(passphrase, 0, strlen(passphrase)); - xfree(passphrase); - if (success || try_next) - break; - debug2("bad passphrase given, try again..."); - } - if (!success) { - key_free(k); - return 0; - } - } - ret = sign_and_send_pubkey(authctxt, k, dsa_sign_cb); - key_free(k); - return ret; -} - -/* sign callback */ -int agent_sign_cb(Authctxt *authctxt, Key *key, unsigned char **sigp, int *lenp, - unsigned char *data, int datalen) -{ - return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen); -} - -int -userauth_pubkey_agent(Authctxt *authctxt) -{ - static int called = 0; - char *comment; - Key *k; - int ret; - - if (called == 0) { - k = ssh_get_first_identity(authctxt->agent, &comment, 2); - called = 1; - } else { - k = ssh_get_next_identity(authctxt->agent, &comment, 2); - } - if (k == NULL) { - debug2("no more DSA keys from agent"); - return 0; - } - debug("trying DSA agent key %s", comment); - xfree(comment); - ret = sign_and_send_pubkey(authctxt, k, agent_sign_cb); - key_free(k); - return ret; -} - -int -userauth_pubkey(Authctxt *authctxt) -{ - static int idx = 0; - int sent = 0; - - if (authctxt->agent != NULL) - sent = userauth_pubkey_agent(authctxt); - while (sent == 0 && idx < options.num_identity_files2) - sent = userauth_pubkey_identity(authctxt, options.identity_files2[idx++]); - return sent; -} - -/* - * Send userauth request message specifying keyboard-interactive method. - */ -int -userauth_kbdint(Authctxt *authctxt) -{ - static int attempt = 0; - - if (attempt++ >= options.number_of_password_prompts) - return 0; - - debug2("userauth_kbdint"); - 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(""); /* lang */ - packet_put_cstring(options.kbd_interactive_devices ? - options.kbd_interactive_devices : ""); - packet_send(); - packet_write_wait(); - - dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); - return 1; -} - -/* - * parse SSH2_MSG_USERAUTH_INFO_REQUEST, prompt user and send - * SSH2_MSG_USERAUTH_INFO_RESPONSE - */ -void -input_userauth_info_req(int type, int plen, void *ctxt) -{ - Authctxt *authctxt = ctxt; - char *name = NULL; - char *inst = NULL; - char *lang = NULL; - char *prompt = NULL; - char *response = NULL; - unsigned int num_prompts, i; - int echo = 0; - - debug2("input_userauth_info_req"); - - if (authctxt == NULL) - fatal("input_userauth_info_req: no authentication context"); - - name = packet_get_string(NULL); - inst = packet_get_string(NULL); - lang = packet_get_string(NULL); - - if (strlen(name) > 0) - cli_mesg(name); - xfree(name); - - if (strlen(inst) > 0) - cli_mesg(inst); - xfree(inst); - xfree(lang); /* unused */ - - num_prompts = packet_get_int(); - /* - * Begin to build info response packet based on prompts requested. - * We commit to providing the correct number of responses, so if - * further on we run into a problem that prevents this, we have to - * be sure and clean this up and send a correct error response. - */ - packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); - packet_put_int(num_prompts); - - for (i = 0; i < num_prompts; i++) { - prompt = packet_get_string(NULL); - echo = packet_get_char(); - - response = cli_prompt(prompt, echo); - - ssh_put_password(response); - memset(response, 0, strlen(response)); - xfree(response); - xfree(prompt); - } - packet_done(); /* done with parsing incoming message. */ - - packet_send(); - packet_write_wait(); -} - -/* find auth method */ - -#define DELIM "," - -static char *def_authlist = "publickey,password"; -static char *authlist_current = NULL; /* clean copy used for comparison */ -static char *authname_current = NULL; /* last used auth method */ -static char *authlist_working = NULL; /* copy that gets modified by strtok_r() */ -static char *authlist_state = NULL; /* state variable for strtok_r() */ - -/* - * Before starting to use a new authentication method list sent by the - * server, reset internal variables. This should also be called when - * finished processing server list to free resources. - */ -void -authmethod_clear() -{ - if (authlist_current != NULL) { - xfree(authlist_current); - authlist_current = NULL; - } - if (authlist_working != NULL) { - xfree(authlist_working); - authlist_working = NULL; - } - if (authname_current != NULL) { - xfree(authname_current); - authlist_state = NULL; - } - if (authlist_state != NULL) - authlist_state = NULL; - return; -} - -/* - * given auth method name, if configurable options permit this method fill - * in auth_ident field and return true, otherwise return false. - */ -int -authmethod_is_enabled(Authmethod *method) -{ - if (method == NULL) - return 0; - /* return false if options indicate this method is disabled */ - if (method->enabled == NULL || *method->enabled == 0) - return 0; - /* return false if batch mode is enabled but method needs interactive mode */ - if (method->batch_flag != NULL && *method->batch_flag != 0) - return 0; - return 1; -} - -Authmethod * -authmethod_lookup(const char *name) -{ - Authmethod *method = NULL; - if (name != NULL) - for (method = authmethods; method->name != NULL; method++) - if (strcmp(name, method->name) == 0) - return method; - debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); - return NULL; -} - -/* - * 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. If the server sends a nil list after - * previously sending a valid list, continue using the list originally - * sent. - */ - -Authmethod * -authmethod_get(char *authlist) -{ - char *name = NULL, *authname_old; - Authmethod *method = NULL; - - /* Use a suitable default if we're passed a nil list. */ - if (authlist == NULL || strlen(authlist) == 0) - authlist = def_authlist; - - if (authlist_current == NULL || strcmp(authlist, authlist_current) != 0) { - /* start over if passed a different list */ - debug3("start over, passed a different list"); - authmethod_clear(); - authlist_current = xstrdup(authlist); - authlist_working = xstrdup(authlist); - name = strtok_r(authlist_working, DELIM, &authlist_state); - } else { - /* - * try to use previously used authentication method - * or continue to use previously passed list - */ - name = (authname_current != NULL) ? - authname_current : strtok_r(NULL, DELIM, &authlist_state); - } - - while (name != NULL) { - debug3("authmethod_lookup %s", name); - method = authmethod_lookup(name); - if (method != NULL && authmethod_is_enabled(method)) { - debug3("authmethod_is_enabled %s", name); - break; - } - name = strtok_r(NULL, DELIM, &authlist_state); - method = NULL; - } - - authname_old = authname_current; - if (method != NULL) { - debug("next auth method to try is %s", name); - authname_current = xstrdup(name); - } else { - debug("no more auth methods to try"); - authname_current = NULL; - } - - if (authname_old != NULL) - xfree(authname_old); - - return (method); -} |