| /* $OpenBSD: sshconnect2.c,v 1.305 2019/05/31 03:20:07 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 |
| * 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" |
| |
| #include <sys/types.h> |
| #include <sys/socket.h> |
| #include <sys/wait.h> |
| #include <sys/stat.h> |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <netdb.h> |
| #include <pwd.h> |
| #include <signal.h> |
| #include <stdarg.h> |
| #include <stdio.h> |
| #include <string.h> |
| #include <unistd.h> |
| #if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H) && !defined(BROKEN_STRNVIS) |
| #include <vis.h> |
| #endif |
| |
| #include "openbsd-compat/sys-queue.h" |
| |
| #include "xmalloc.h" |
| #include "ssh.h" |
| #include "ssh2.h" |
| #include "sshbuf.h" |
| #include "packet.h" |
| #include "compat.h" |
| #include "cipher.h" |
| #include "sshkey.h" |
| #include "kex.h" |
| #include "myproposal.h" |
| #include "sshconnect.h" |
| #include "authfile.h" |
| #include "dh.h" |
| #include "authfd.h" |
| #include "log.h" |
| #include "misc.h" |
| #include "readconf.h" |
| #include "match.h" |
| #include "dispatch.h" |
| #include "canohost.h" |
| #include "msg.h" |
| #include "pathnames.h" |
| #include "uidswap.h" |
| #include "hostfile.h" |
| #include "ssherr.h" |
| #include "utf8.h" |
| |
| #ifdef GSSAPI |
| #include "ssh-gss.h" |
| #endif |
| |
| /* import */ |
| extern char *client_version_string; |
| extern char *server_version_string; |
| extern Options options; |
| |
| /* |
| * SSH2 key exchange |
| */ |
| |
| u_char *session_id2 = NULL; |
| u_int session_id2_len = 0; |
| |
| char *xxx_host; |
| struct sockaddr *xxx_hostaddr; |
| |
| static int |
| verify_host_key_callback(struct sshkey *hostkey, struct ssh *ssh) |
| { |
| if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) |
| fatal("Host key verification failed."); |
| return 0; |
| } |
| |
| static char * |
| order_hostkeyalgs(char *host, struct sockaddr *hostaddr, u_short port) |
| { |
| char *oavail, *avail, *first, *last, *alg, *hostname, *ret; |
| size_t maxlen; |
| struct hostkeys *hostkeys; |
| int ktype; |
| u_int i; |
| |
| /* Find all hostkeys for this hostname */ |
| get_hostfile_hostname_ipaddr(host, hostaddr, port, &hostname, NULL); |
| hostkeys = init_hostkeys(); |
| for (i = 0; i < options.num_user_hostfiles; i++) |
| load_hostkeys(hostkeys, hostname, options.user_hostfiles[i]); |
| for (i = 0; i < options.num_system_hostfiles; i++) |
| load_hostkeys(hostkeys, hostname, options.system_hostfiles[i]); |
| |
| oavail = avail = xstrdup(KEX_DEFAULT_PK_ALG); |
| maxlen = strlen(avail) + 1; |
| first = xmalloc(maxlen); |
| last = xmalloc(maxlen); |
| *first = *last = '\0'; |
| |
| #define ALG_APPEND(to, from) \ |
| do { \ |
| if (*to != '\0') \ |
| strlcat(to, ",", maxlen); \ |
| strlcat(to, from, maxlen); \ |
| } while (0) |
| |
| while ((alg = strsep(&avail, ",")) && *alg != '\0') { |
| if ((ktype = sshkey_type_from_name(alg)) == KEY_UNSPEC) |
| fatal("%s: unknown alg %s", __func__, alg); |
| if (lookup_key_in_hostkeys_by_type(hostkeys, |
| sshkey_type_plain(ktype), NULL)) |
| ALG_APPEND(first, alg); |
| else |
| ALG_APPEND(last, alg); |
| } |
| #undef ALG_APPEND |
| xasprintf(&ret, "%s%s%s", first, |
| (*first == '\0' || *last == '\0') ? "" : ",", last); |
| if (*first != '\0') |
| debug3("%s: prefer hostkeyalgs: %s", __func__, first); |
| |
| free(first); |
| free(last); |
| free(hostname); |
| free(oavail); |
| free_hostkeys(hostkeys); |
| |
| return ret; |
| } |
| |
| void |
| ssh_kex2(struct ssh *ssh, char *host, struct sockaddr *hostaddr, u_short port) |
| { |
| char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT }; |
| char *s, *all_key; |
| int r; |
| |
| xxx_host = host; |
| xxx_hostaddr = hostaddr; |
| |
| if ((s = kex_names_cat(options.kex_algorithms, "ext-info-c")) == NULL) |
| fatal("%s: kex_names_cat", __func__); |
| myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(s); |
| myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
| compat_cipher_proposal(options.ciphers); |
| myproposal[PROPOSAL_ENC_ALGS_STOC] = |
| compat_cipher_proposal(options.ciphers); |
| myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
| myproposal[PROPOSAL_COMP_ALGS_STOC] = options.compression ? |
| "zlib@openssh.com,zlib,none" : "none,zlib@openssh.com,zlib"; |
| myproposal[PROPOSAL_MAC_ALGS_CTOS] = |
| myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; |
| if (options.hostkeyalgorithms != NULL) { |
| all_key = sshkey_alg_list(0, 0, 1, ','); |
| if (kex_assemble_names(&options.hostkeyalgorithms, |
| KEX_DEFAULT_PK_ALG, all_key) != 0) |
| fatal("%s: kex_assemble_namelist", __func__); |
| free(all_key); |
| myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = |
| compat_pkalg_proposal(options.hostkeyalgorithms); |
| } else { |
| /* Enforce default */ |
| options.hostkeyalgorithms = xstrdup(KEX_DEFAULT_PK_ALG); |
| /* Prefer algorithms that we already have keys for */ |
| myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = |
| compat_pkalg_proposal( |
| order_hostkeyalgs(host, hostaddr, port)); |
| } |
| |
| if (options.rekey_limit || options.rekey_interval) |
| ssh_packet_set_rekey_limits(ssh, options.rekey_limit, |
| options.rekey_interval); |
| |
| /* start key exchange */ |
| if ((r = kex_setup(ssh, myproposal)) != 0) |
| fatal("kex_setup: %s", ssh_err(r)); |
| #ifdef WITH_OPENSSL |
| ssh->kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_client; |
| ssh->kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_client; |
| ssh->kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_client; |
| ssh->kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_client; |
| ssh->kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_client; |
| ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; |
| ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; |
| # ifdef OPENSSL_HAS_ECC |
| ssh->kex->kex[KEX_ECDH_SHA2] = kex_gen_client; |
| # endif |
| #endif |
| ssh->kex->kex[KEX_C25519_SHA256] = kex_gen_client; |
| ssh->kex->kex[KEX_KEM_SNTRUP4591761X25519_SHA512] = kex_gen_client; |
| ssh->kex->verify_host_key=&verify_host_key_callback; |
| |
| ssh_dispatch_run_fatal(ssh, DISPATCH_BLOCK, &ssh->kex->done); |
| |
| /* remove ext-info from the KEX proposals for rekeying */ |
| myproposal[PROPOSAL_KEX_ALGS] = |
| compat_kex_proposal(options.kex_algorithms); |
| if ((r = kex_prop2buf(ssh->kex->my, myproposal)) != 0) |
| fatal("kex_prop2buf: %s", ssh_err(r)); |
| |
| session_id2 = ssh->kex->session_id; |
| session_id2_len = ssh->kex->session_id_len; |
| |
| #ifdef DEBUG_KEXDH |
| /* send 1st encrypted/maced/compressed message */ |
| if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 || |
| (r = sshpkt_put_cstring(ssh, "markus")) != 0 || |
| (r = sshpkt_send(ssh)) != 0 || |
| (r = ssh_packet_write_wait(ssh)) != 0) |
| fatal("%s: %s", __func__, ssh_err(r)); |
| #endif |
| } |
| |
| /* |
| * Authenticate user |
| */ |
| |
| typedef struct cauthctxt Authctxt; |
| typedef struct cauthmethod Authmethod; |
| typedef struct identity Identity; |
| typedef struct idlist Idlist; |
| |
| struct identity { |
| TAILQ_ENTRY(identity) next; |
| int agent_fd; /* >=0 if agent supports key */ |
| struct sshkey *key; /* public/private key */ |
| char *filename; /* comment for agent-only keys */ |
| int tried; |
| int isprivate; /* key points to the private key */ |
| int userprovided; |
| }; |
| TAILQ_HEAD(idlist, identity); |
| |
| struct cauthctxt { |
| const char *server_user; |
| const char *local_user; |
| const char *host; |
| const char *service; |
| struct cauthmethod *method; |
| sig_atomic_t success; |
| char *authlist; |
| #ifdef GSSAPI |
| /* gssapi */ |
| gss_OID_set gss_supported_mechs; |
| u_int mech_tried; |
| #endif |
| /* pubkey */ |
| struct idlist keys; |
| int agent_fd; |
| /* hostbased */ |
| Sensitive *sensitive; |
| char *oktypes, *ktypes; |
| const char *active_ktype; |
| /* kbd-interactive */ |
| int info_req_seen; |
| int attempt_kbdint; |
| /* password */ |
| int attempt_passwd; |
| /* generic */ |
| void *methoddata; |
| }; |
| |
| struct cauthmethod { |
| char *name; /* string to compare against server's list */ |
| int (*userauth)(struct ssh *ssh); |
| void (*cleanup)(struct ssh *ssh); |
| int *enabled; /* flag in option struct that enables method */ |
| int *batch_flag; /* flag in option struct that disables method */ |
| }; |
| |
| static int input_userauth_service_accept(int, u_int32_t, struct ssh *); |
| static int input_userauth_ext_info(int, u_int32_t, struct ssh *); |
| static int input_userauth_success(int, u_int32_t, struct ssh *); |
| static int input_userauth_failure(int, u_int32_t, struct ssh *); |
| static int input_userauth_banner(int, u_int32_t, struct ssh *); |
| static int input_userauth_error(int, u_int32_t, struct ssh *); |
| static int input_userauth_info_req(int, u_int32_t, struct ssh *); |
| static int input_userauth_pk_ok(int, u_int32_t, struct ssh *); |
| static int input_userauth_passwd_changereq(int, u_int32_t, struct ssh *); |
| |
| static int userauth_none(struct ssh *); |
| static int userauth_pubkey(struct ssh *); |
| static int userauth_passwd(struct ssh *); |
| static int userauth_kbdint(struct ssh *); |
| static int userauth_hostbased(struct ssh *); |
| |
| #ifdef GSSAPI |
| static int userauth_gssapi(struct ssh *); |
| static void userauth_gssapi_cleanup(struct ssh *); |
| static int input_gssapi_response(int type, u_int32_t, struct ssh *); |
| static int input_gssapi_token(int type, u_int32_t, struct ssh *); |
| static int input_gssapi_error(int, u_int32_t, struct ssh *); |
| static int input_gssapi_errtok(int, u_int32_t, struct ssh *); |
| #endif |
| |
| void userauth(struct ssh *, char *); |
| |
| static void pubkey_cleanup(struct ssh *); |
| static int sign_and_send_pubkey(struct ssh *ssh, Identity *); |
| static void pubkey_prepare(Authctxt *); |
| static void pubkey_reset(Authctxt *); |
| static struct sshkey *load_identity_file(Identity *); |
| |
| static Authmethod *authmethod_get(char *authlist); |
| static Authmethod *authmethod_lookup(const char *name); |
| static char *authmethods_get(void); |
| |
| Authmethod authmethods[] = { |
| #ifdef GSSAPI |
| {"gssapi-with-mic", |
| userauth_gssapi, |
| userauth_gssapi_cleanup, |
| &options.gss_authentication, |
| NULL}, |
| #endif |
| {"hostbased", |
| userauth_hostbased, |
| NULL, |
| &options.hostbased_authentication, |
| NULL}, |
| {"publickey", |
| userauth_pubkey, |
| NULL, |
| &options.pubkey_authentication, |
| NULL}, |
| {"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} |
| }; |
| |
| void |
| ssh_userauth2(struct ssh *ssh, const char *local_user, |
| const char *server_user, char *host, Sensitive *sensitive) |
| { |
| Authctxt authctxt; |
| int r; |
| |
| if (options.challenge_response_authentication) |
| options.kbd_interactive_authentication = 1; |
| if (options.preferred_authentications == NULL) |
| options.preferred_authentications = authmethods_get(); |
| |
| /* setup authentication context */ |
| memset(&authctxt, 0, sizeof(authctxt)); |
| 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.methoddata = NULL; |
| authctxt.sensitive = sensitive; |
| authctxt.active_ktype = authctxt.oktypes = authctxt.ktypes = NULL; |
| authctxt.info_req_seen = 0; |
| authctxt.attempt_kbdint = 0; |
| authctxt.attempt_passwd = 0; |
| #if GSSAPI |
| authctxt.gss_supported_mechs = NULL; |
| authctxt.mech_tried = 0; |
| #endif |
| authctxt.agent_fd = -1; |
| pubkey_prepare(&authctxt); |
| if (authctxt.method == NULL) { |
| fatal("%s: internal error: cannot send userauth none request", |
| __func__); |
| } |
| |
| if ((r = sshpkt_start(ssh, SSH2_MSG_SERVICE_REQUEST)) != 0 || |
| (r = sshpkt_put_cstring(ssh, "ssh-userauth")) != 0 || |
| (r = sshpkt_send(ssh)) != 0) |
| fatal("%s: %s", __func__, ssh_err(r)); |
| |
| ssh->authctxt = &authctxt; |
| ssh_dispatch_init(ssh, &input_userauth_error); |
| ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &input_userauth_ext_info); |
| ssh_dispatch_set(ssh, SSH2_MSG_SERVICE_ACCEPT, &input_userauth_service_accept); |
| ssh_dispatch_run_fatal(ssh, DISPATCH_BLOCK, &authctxt.success); /* loop until success */ |
| pubkey_cleanup(ssh); |
| ssh->authctxt = NULL; |
| |
| ssh_dispatch_range(ssh, SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); |
| |
| if (!authctxt.success) |
| fatal("Authentication failed."); |
| debug("Authentication succeeded (%s).", authctxt.method->name); |
| } |
| |
| /* ARGSUSED */ |
| static int |
| input_userauth_service_accept(int type, u_int32_t seq, struct ssh *ssh) |
| { |
| int r; |
| |
| if (ssh_packet_remaining(ssh) > 0) { |
| char *reply; |
| |
| if ((r = sshpkt_get_cstring(ssh, &reply, NULL)) != 0) |
| goto out; |
| debug2("service_accept: %s", reply); |
| free(reply); |
| } else { |
| debug2("buggy server: service_accept w/o service"); |
| } |
| if ((r = sshpkt_get_end(ssh)) != 0) |
| goto out; |
| debug("SSH2_MSG_SERVICE_ACCEPT received"); |
| |
| /* initial userauth request */ |
| userauth_none(ssh); |
| |
| ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &input_userauth_error); |
| ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); |
| ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); |
| ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); |
| r = 0; |
| out: |
| return r; |
| } |
| |
| /* ARGSUSED */ |
| static int |
| input_userauth_ext_info(int type, u_int32_t seqnr, struct ssh *ssh) |
| { |
| return kex_input_ext_info(type, seqnr, ssh); |
| } |
| |
| void |
| userauth(struct ssh *ssh, char *authlist) |
| { |
| Authctxt *authctxt = (Authctxt *)ssh->authctxt; |
| |
| if (authctxt->method != NULL && authctxt->method->cleanup != NULL) |
| authctxt->method->cleanup(ssh); |
| |
| free(authctxt->methoddata); |
| authctxt->methoddata = NULL; |
| if (authlist == NULL) { |
| authlist = authctxt->authlist; |
| } else { |
| free(authctxt->authlist); |
| authctxt->authlist = authlist; |
| } |
| for (;;) { |
| Authmethod *method = authmethod_get(authlist); |
| if (method == NULL) |
| fatal("%s@%s: Permission denied (%s).", |
| authctxt->server_user, authctxt->host, authlist); |
| authctxt->method = method; |
| |
| /* reset the per method handler */ |
| ssh_dispatch_range(ssh, SSH2_MSG_USERAUTH_PER_METHOD_MIN, |
| SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); |
| |
| /* and try new method */ |
| if (method->userauth(ssh) != 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; |
| } |
| } |
| } |
| |
| /* ARGSUSED */ |
| static int |
| input_userauth_error(int type, u_int32_t seq, struct ssh *ssh) |
| { |
| fatal("%s: bad message during authentication: type %d", __func__, type); |
| return 0; |
| } |
| |
| /* ARGSUSED */ |
| static int |
| input_userauth_banner(int type, u_int32_t seq, struct ssh *ssh) |
| { |
| char *msg = NULL; |
| size_t len; |
| int r; |
| |
| debug3("%s", __func__); |
| if ((r = sshpkt_get_cstring(ssh, &msg, &len)) != 0 || |
| (r = sshpkt_get_cstring(ssh, NULL, NULL)) != 0) |
| goto out; |
| if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) |
| fmprintf(stderr, "%s", msg); |
| r = 0; |
| out: |
| free(msg); |
| return r; |
| } |
| |
| /* ARGSUSED */ |
| static int |
| input_userauth_success(int type, u_int32_t seq, struct ssh *ssh) |
| { |
| Authctxt *authctxt = ssh->authctxt; |
| |
| if (authctxt == NULL) |
| fatal("%s: no authentication context", __func__); |
| free(authctxt->authlist); |
| authctxt->authlist = NULL; |
| if (authctxt->method != NULL && authctxt->method->cleanup != NULL) |
| authctxt->method->cleanup(ssh); |
| free(authctxt->methoddata); |
| authctxt->methoddata = NULL; |
| authctxt->success = 1; /* break out */ |
| return 0; |
| } |
| |
| #if 0 |
| static int |
| input_userauth_success_unexpected(int type, u_int32_t seq, struct ssh *ssh) |
| { |
| Authctxt *authctxt = ssh->authctxt; |
| |
| if (authctxt == NULL) |
| fatal("%s: no authentication context", __func__); |
| |
| fatal("Unexpected authentication success during %s.", |
| authctxt->method->name); |
| return 0; |
| } |
| #endif |
| |
| /* ARGSUSED */ |
| static int |
| input_userauth_failure(int type, u_int32_t seq, struct ssh *ssh) |
| { |
| Authctxt *authctxt = ssh->authctxt; |
| char *authlist = NULL; |
| u_char partial; |
| int r; |
| |
| if (authctxt == NULL) |
| fatal("input_userauth_failure: no authentication context"); |
| |
| if ((r = sshpkt_get_cstring(ssh, &authlist, NULL)) != 0 || |
| (r = sshpkt_get_u8(ssh, &partial)) != 0 || |
| (r = sshpkt_get_end(ssh)) != 0) |
| goto out; |
| |
| if (partial != 0) { |
| verbose("Authenticated with partial success."); |
| /* reset state */ |
| pubkey_reset(authctxt); |
| } |
| debug("Authentications that can continue: %s", authlist); |
| |
| userauth(ssh, authlist); |
| authlist = NULL; |
| out: |
| free(authlist); |
| return 0; |
| } |
| |
| /* |
| * Format an identity for logging including filename, key type, fingerprint |
| * and location (agent, etc.). Caller must free. |
| */ |
| static char * |
| format_identity(Identity *id) |
| { |
| char *fp = NULL, *ret = NULL; |
| |
| if (id->key != NULL) { |
| fp = sshkey_fingerprint(id->key, options.fingerprint_hash, |
| SSH_FP_DEFAULT); |
| } |
| xasprintf(&ret, "%s %s%s%s%s%s%s", |
| id->filename, |
| id->key ? sshkey_type(id->key) : "", id->key ? " " : "", |
| fp ? fp : "", |
| id->userprovided ? " explicit" : "", |
| (id->key && (id->key->flags & SSHKEY_FLAG_EXT)) ? " token" : "", |
| id->agent_fd != -1 ? " agent" : ""); |
| free(fp); |
| return ret; |
| } |
| |
| /* ARGSUSED */ |
| static int |
| input_userauth_pk_ok(int type, u_int32_t seq, struct ssh *ssh) |
| { |
| Authctxt *authctxt = ssh->authctxt; |
| struct sshkey *key = NULL; |
| Identity *id = NULL; |
| int pktype, found = 0, sent = 0; |
| size_t blen; |
| char *pkalg = NULL, *fp = NULL, *ident = NULL; |
| u_char *pkblob = NULL; |
| int r; |
| |
| if (authctxt == NULL) |
| fatal("input_userauth_pk_ok: no authentication context"); |
| |
| if ((r = sshpkt_get_cstring(ssh, &pkalg, NULL)) != 0 || |
| (r = sshpkt_get_string(ssh, &pkblob, &blen)) != 0 || |
| (r = sshpkt_get_end(ssh)) != 0) |
| goto done; |
| |
| if ((pktype = sshkey_type_from_name(pkalg)) == KEY_UNSPEC) { |
| debug("%s: server sent unknown pkalg %s", __func__, pkalg); |
| goto done; |
| } |
| if ((r = sshkey_from_blob(pkblob, blen, &key)) != 0) { |
| debug("no key from blob. pkalg %s: %s", pkalg, ssh_err(r)); |
| goto done; |
| } |
| if (key->type != pktype) { |
| error("input_userauth_pk_ok: type mismatch " |
| "for decoded key (received %d, expected %d)", |
| key->type, pktype); |
| goto done; |
| } |
| |
| /* |
| * search keys in the reverse order, because last candidate has been |
| * moved to the end of the queue. this also avoids confusion by |
| * duplicate keys |
| */ |
| TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { |
| if (sshkey_equal(key, id->key)) { |
| found = 1; |
| break; |
| } |
| } |
| if (!found || id == NULL) { |
| fp = sshkey_fingerprint(key, options.fingerprint_hash, |
| SSH_FP_DEFAULT); |
| error("%s: server replied with unknown key: %s %s", __func__, |
| sshkey_type(key), fp == NULL ? "<ERROR>" : fp); |
| goto done; |
| } |
| ident = format_identity(id); |
| debug("Server accepts key: %s", ident); |
| sent = sign_and_send_pubkey(ssh, id); |
| r = 0; |
| done: |
| sshkey_free(key); |
| free(ident); |
| free(fp); |
| free(pkalg); |
| free(pkblob); |
| |
| /* try another method if we did not send a packet */ |
| if (r == 0 && sent == 0) |
| userauth(ssh, NULL); |
| return r; |
| } |
| |
| #ifdef GSSAPI |
| static int |
| userauth_gssapi(struct ssh *ssh) |
| { |
| Authctxt *authctxt = (Authctxt *)ssh->authctxt; |
| Gssctxt *gssctxt = NULL; |
| OM_uint32 min; |
| int r, ok = 0; |
| gss_OID mech = NULL; |
| |
| /* Try one GSSAPI method at a time, rather than sending them all at |
| * once. */ |
| |
| if (authctxt->gss_supported_mechs == NULL) |
| gss_indicate_mechs(&min, &authctxt->gss_supported_mechs); |
| |
| /* Check to see whether the mechanism is usable before we offer it */ |
| while (authctxt->mech_tried < authctxt->gss_supported_mechs->count && |
| !ok) { |
| mech = &authctxt->gss_supported_mechs-> |
| elements[authctxt->mech_tried]; |
| /* My DER encoding requires length<128 */ |
| if (mech->length < 128 && ssh_gssapi_check_mechanism(&gssctxt, |
| mech, authctxt->host)) { |
| ok = 1; /* Mechanism works */ |
| } else { |
| authctxt->mech_tried++; |
| } |
| } |
| |
| if (!ok || mech == NULL) |
| return 0; |
| |
| authctxt->methoddata=(void *)gssctxt; |
| |
| if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || |
| (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || |
| (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || |
| (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || |
| (r = sshpkt_put_u32(ssh, 1)) != 0 || |
| (r = sshpkt_put_u32(ssh, (mech->length) + 2)) != 0 || |
| (r = sshpkt_put_u8(ssh, SSH_GSS_OIDTYPE)) != 0 || |
| (r = sshpkt_put_u8(ssh, mech->length)) != 0 || |
| (r = sshpkt_put(ssh, mech->elements, mech->length)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) |
| fatal("%s: %s", __func__, ssh_err(r)); |
| |
| ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); |
| ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); |
| ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); |
| ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); |
| |
| authctxt->mech_tried++; /* Move along to next candidate */ |
| |
| return 1; |
| } |
| |
| static void |
| userauth_gssapi_cleanup(struct ssh *ssh) |
| { |
| Authctxt *authctxt = (Authctxt *)ssh->authctxt; |
| Gssctxt *gssctxt = (Gssctxt *)authctxt->methoddata; |
| |
| ssh_gssapi_delete_ctx(&gssctxt); |
| authctxt->methoddata = NULL; |
| |
| free(authctxt->gss_supported_mechs); |
| authctxt->gss_supported_mechs = NULL; |
| } |
| |
| static OM_uint32 |
| process_gssapi_token(struct ssh *ssh, gss_buffer_t recv_tok) |
| { |
| Authctxt *authctxt = ssh->authctxt; |
| Gssctxt *gssctxt = authctxt->methoddata; |
| gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; |
| gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; |
| gss_buffer_desc gssbuf; |
| OM_uint32 status, ms, flags; |
| int r; |
| |
| status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, |
| recv_tok, &send_tok, &flags); |
| |
| if (send_tok.length > 0) { |
| u_char type = GSS_ERROR(status) ? |
| SSH2_MSG_USERAUTH_GSSAPI_ERRTOK : |
| SSH2_MSG_USERAUTH_GSSAPI_TOKEN; |
| |
| if ((r = sshpkt_start(ssh, type)) != 0 || |
| (r = sshpkt_put_string(ssh, send_tok.value, |
| send_tok.length)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) |
| fatal("%s: %s", __func__, ssh_err(r)); |
| |
| gss_release_buffer(&ms, &send_tok); |
| } |
| |
| if (status == GSS_S_COMPLETE) { |
| /* send either complete or MIC, depending on mechanism */ |
| if (!(flags & GSS_C_INTEG_FLAG)) { |
| if ((r = sshpkt_start(ssh, |
| SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) |
| fatal("%s: %s", __func__, ssh_err(r)); |
| } else { |
| struct sshbuf *b; |
| |
| if ((b = sshbuf_new()) == NULL) |
| fatal("%s: sshbuf_new failed", __func__); |
| ssh_gssapi_buildmic(b, authctxt->server_user, |
| authctxt->service, "gssapi-with-mic"); |
| |
| if ((gssbuf.value = sshbuf_mutable_ptr(b)) == NULL) |
| fatal("%s: sshbuf_mutable_ptr failed", __func__); |
| gssbuf.length = sshbuf_len(b); |
| |
| status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); |
| |
| if (!GSS_ERROR(status)) { |
| if ((r = sshpkt_start(ssh, |
| SSH2_MSG_USERAUTH_GSSAPI_MIC)) != 0 || |
| (r = sshpkt_put_string(ssh, mic.value, |
| mic.length)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) |
| fatal("%s: %s", __func__, ssh_err(r)); |
| } |
| |
| sshbuf_free(b); |
| gss_release_buffer(&ms, &mic); |
| } |
| } |
| |
| return status; |
| } |
| |
| /* ARGSUSED */ |
| static int |
| input_gssapi_response(int type, u_int32_t plen, struct ssh *ssh) |
| { |
| Authctxt *authctxt = ssh->authctxt; |
| Gssctxt *gssctxt; |
| size_t oidlen; |
| u_char *oidv = NULL; |
| int r; |
| |
| if (authctxt == NULL) |
| fatal("input_gssapi_response: no authentication context"); |
| gssctxt = authctxt->methoddata; |
| |
| /* Setup our OID */ |
| if ((r = sshpkt_get_string(ssh, &oidv, &oidlen)) != 0) |
| goto done; |
| |
| if (oidlen <= 2 || |
| oidv[0] != SSH_GSS_OIDTYPE || |
| oidv[1] != oidlen - 2) { |
| debug("Badly encoded mechanism OID received"); |
| userauth(ssh, NULL); |
| goto ok; |
| } |
| |
| if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) |
| fatal("Server returned different OID than expected"); |
| |
| if ((r = sshpkt_get_end(ssh)) != 0) |
| goto done; |
| |
| if (GSS_ERROR(process_gssapi_token(ssh, GSS_C_NO_BUFFER))) { |
| /* Start again with next method on list */ |
| debug("Trying to start again"); |
| userauth(ssh, NULL); |
| goto ok; |
| } |
| ok: |
| r = 0; |
| done: |
| free(oidv); |
| return r; |
| } |
| |
| /* ARGSUSED */ |
| static int |
| input_gssapi_token(int type, u_int32_t plen, struct ssh *ssh) |
| { |
| Authctxt *authctxt = ssh->authctxt; |
| gss_buffer_desc recv_tok; |
| u_char *p = NULL; |
| size_t len; |
| OM_uint32 status; |
| int r; |
| |
| if (authctxt == NULL) |
| fatal("input_gssapi_response: no authentication context"); |
| |
| if ((r = sshpkt_get_string(ssh, &p, &len)) != 0 || |
| (r = sshpkt_get_end(ssh)) != 0) |
| goto out; |
| |
| recv_tok.value = p; |
| recv_tok.length = len; |
| status = process_gssapi_token(ssh, &recv_tok); |
| |
| /* Start again with the next method in the list */ |
| if (GSS_ERROR(status)) { |
| userauth(ssh, NULL); |
| /* ok */ |
| } |
| r = 0; |
| out: |
| free(p); |
| return r; |
| } |
| |
| /* ARGSUSED */ |
| static int |
| input_gssapi_errtok(int type, u_int32_t plen, struct ssh *ssh) |
| { |
| Authctxt *authctxt = ssh->authctxt; |
| Gssctxt *gssctxt; |
| gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; |
| gss_buffer_desc recv_tok; |
| OM_uint32 ms; |
| u_char *p = NULL; |
| size_t len; |
| int r; |
| |
| if (authctxt == NULL) |
| fatal("input_gssapi_response: no authentication context"); |
| gssctxt = authctxt->methoddata; |
| |
| if ((r = sshpkt_get_string(ssh, &p, &len)) != 0 || |
| (r = sshpkt_get_end(ssh)) != 0) { |
| free(p); |
| return r; |
| } |
| |
| /* Stick it into GSSAPI and see what it says */ |
| recv_tok.value = p; |
| recv_tok.length = len; |
| (void)ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, |
| &recv_tok, &send_tok, NULL); |
| free(p); |
| gss_release_buffer(&ms, &send_tok); |
| |
| /* Server will be returning a failed packet after this one */ |
| return 0; |
| } |
| |
| /* ARGSUSED */ |
| static int |
| input_gssapi_error(int type, u_int32_t plen, struct ssh *ssh) |
| { |
| char *msg = NULL; |
| char *lang = NULL; |
| int r; |
| |
| if ((r = sshpkt_get_u32(ssh, NULL)) != 0 || /* maj */ |
| (r = sshpkt_get_u32(ssh, NULL)) != 0 || /* min */ |
| (r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || |
| (r = sshpkt_get_cstring(ssh, &lang, NULL)) != 0) |
| goto out; |
| r = sshpkt_get_end(ssh); |
| debug("Server GSSAPI Error:\n%s", msg); |
| out: |
| free(msg); |
| free(lang); |
| return r; |
| } |
| #endif /* GSSAPI */ |
| |
| static int |
| userauth_none(struct ssh *ssh) |
| { |
| Authctxt *authctxt = (Authctxt *)ssh->authctxt; |
| int r; |
| |
| /* initial userauth request */ |
| if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || |
| (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || |
| (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || |
| (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) |
| fatal("%s: %s", __func__, ssh_err(r)); |
| return 1; |
| } |
| |
| static int |
| userauth_passwd(struct ssh *ssh) |
| { |
| Authctxt *authctxt = (Authctxt *)ssh->authctxt; |
| char *password, *prompt = NULL; |
| const char *host = options.host_key_alias ? options.host_key_alias : |
| authctxt->host; |
| int r; |
| |
| if (authctxt->attempt_passwd++ >= options.number_of_password_prompts) |
| return 0; |
| |
| if (authctxt->attempt_passwd != 1) |
| error("Permission denied, please try again."); |
| |
| xasprintf(&prompt, "%s@%s's password: ", authctxt->server_user, host); |
| password = read_passphrase(prompt, 0); |
| if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || |
| (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || |
| (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || |
| (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || |
| (r = sshpkt_put_u8(ssh, 0)) != 0 || |
| (r = sshpkt_put_cstring(ssh, password)) != 0 || |
| (r = sshpkt_add_padding(ssh, 64)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) |
| fatal("%s: %s", __func__, ssh_err(r)); |
| |
| free(prompt); |
| if (password != NULL) |
| freezero(password, strlen(password)); |
| |
| ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, |
| &input_userauth_passwd_changereq); |
| |
| return 1; |
| } |
| |
| /* |
| * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST |
| */ |
| /* ARGSUSED */ |
| static int |
| input_userauth_passwd_changereq(int type, u_int32_t seqnr, struct ssh *ssh) |
| { |
| Authctxt *authctxt = ssh->authctxt; |
| char *info = NULL, *lang = NULL, *password = NULL, *retype = NULL; |
| char prompt[256]; |
| const char *host; |
| int r; |
| |
| debug2("input_userauth_passwd_changereq"); |
| |
| if (authctxt == NULL) |
| fatal("input_userauth_passwd_changereq: " |
| "no authentication context"); |
| host = options.host_key_alias ? options.host_key_alias : authctxt->host; |
| |
| if ((r = sshpkt_get_cstring(ssh, &info, NULL)) != 0 || |
| (r = sshpkt_get_cstring(ssh, &lang, NULL)) != 0) |
| goto out; |
| if (strlen(info) > 0) |
| logit("%s", info); |
| if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || |
| (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || |
| (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || |
| (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || |
| (r = sshpkt_put_u8(ssh, 1)) != 0) /* additional info */ |
| goto out; |
| |
| snprintf(prompt, sizeof(prompt), |
| "Enter %.30s@%.128s's old password: ", |
| authctxt->server_user, host); |
| password = read_passphrase(prompt, 0); |
| if ((r = sshpkt_put_cstring(ssh, password)) != 0) |
| goto out; |
| |
| freezero(password, strlen(password)); |
| password = NULL; |
| while (password == NULL) { |
| snprintf(prompt, sizeof(prompt), |
| "Enter %.30s@%.128s's new password: ", |
| authctxt->server_user, host); |
| password = read_passphrase(prompt, RP_ALLOW_EOF); |
| if (password == NULL) { |
| /* bail out */ |
| r = 0; |
| goto out; |
| } |
| snprintf(prompt, sizeof(prompt), |
| "Retype %.30s@%.128s's new password: ", |
| authctxt->server_user, host); |
| retype = read_passphrase(prompt, 0); |
| if (strcmp(password, retype) != 0) { |
| freezero(password, strlen(password)); |
| logit("Mismatch; try again, EOF to quit."); |
| password = NULL; |
| } |
| freezero(retype, strlen(retype)); |
| } |
| if ((r = sshpkt_put_cstring(ssh, password)) != 0 || |
| (r = sshpkt_add_padding(ssh, 64)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) |
| goto out; |
| |
| ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, |
| &input_userauth_passwd_changereq); |
| r = 0; |
| out: |
| if (password) |
| freezero(password, strlen(password)); |
| free(info); |
| free(lang); |
| return r; |
| } |
| |
| /* |
| * Select an algorithm for publickey signatures. |
| * Returns algorithm (caller must free) or NULL if no mutual algorithm found. |
| * |
| * Call with ssh==NULL to ignore server-sig-algs extension list and |
| * only attempt with the key's base signature type. |
| */ |
| static char * |
| key_sig_algorithm(struct ssh *ssh, const struct sshkey *key) |
| { |
| char *allowed, *oallowed, *cp, *tmp, *alg = NULL; |
| |
| /* |
| * The signature algorithm will only differ from the key algorithm |
| * for RSA keys/certs and when the server advertises support for |
| * newer (SHA2) algorithms. |
| */ |
| if (ssh == NULL || ssh->kex->server_sig_algs == NULL || |
| (key->type != KEY_RSA && key->type != KEY_RSA_CERT) || |
| (key->type == KEY_RSA_CERT && (datafellows & SSH_BUG_SIGTYPE))) { |
| /* Filter base key signature alg against our configuration */ |
| return match_list(sshkey_ssh_name(key), |
| options.pubkey_key_types, NULL); |
| } |
| |
| /* |
| * For RSA keys/certs, since these might have a different sig type: |
| * find the first entry in PubkeyAcceptedKeyTypes of the right type |
| * that also appears in the supported signature algorithms list from |
| * the server. |
| */ |
| oallowed = allowed = xstrdup(options.pubkey_key_types); |
| while ((cp = strsep(&allowed, ",")) != NULL) { |
| if (sshkey_type_from_name(cp) != key->type) |
| continue; |
| tmp = match_list(sshkey_sigalg_by_name(cp), ssh->kex->server_sig_algs, NULL); |
| if (tmp != NULL) |
| alg = xstrdup(cp); |
| free(tmp); |
| if (alg != NULL) |
| break; |
| } |
| free(oallowed); |
| return alg; |
| } |
| |
| static int |
| identity_sign(struct identity *id, u_char **sigp, size_t *lenp, |
| const u_char *data, size_t datalen, u_int compat, const char *alg) |
| { |
| struct sshkey *prv; |
| int r; |
| |
| /* The agent supports this key. */ |
| if (id->key != NULL && id->agent_fd != -1) { |
| return ssh_agent_sign(id->agent_fd, id->key, sigp, lenp, |
| data, datalen, alg, compat); |
| } |
| |
| /* |
| * We have already loaded the private key or the private key is |
| * stored in external hardware. |
| */ |
| if (id->key != NULL && |
| (id->isprivate || (id->key->flags & SSHKEY_FLAG_EXT))) { |
| if ((r = sshkey_sign(id->key, sigp, lenp, data, datalen, |
| alg, compat)) != 0) |
| return r; |
| /* |
| * PKCS#11 tokens may not support all signature algorithms, |
| * so check what we get back. |
| */ |
| if ((r = sshkey_check_sigtype(*sigp, *lenp, alg)) != 0) |
| return r; |
| return 0; |
| } |
| |
| /* Load the private key from the file. */ |
| if ((prv = load_identity_file(id)) == NULL) |
| return SSH_ERR_KEY_NOT_FOUND; |
| if (id->key != NULL && !sshkey_equal_public(prv, id->key)) { |
| error("%s: private key %s contents do not match public", |
| __func__, id->filename); |
| return SSH_ERR_KEY_NOT_FOUND; |
| } |
| r = sshkey_sign(prv, sigp, lenp, data, datalen, alg, compat); |
| sshkey_free(prv); |
| return r; |
| } |
| |
| static int |
| id_filename_matches(Identity *id, Identity *private_id) |
| { |
| const char *suffixes[] = { ".pub", "-cert.pub", NULL }; |
| size_t len = strlen(id->filename), plen = strlen(private_id->filename); |
| size_t i, slen; |
| |
| if (strcmp(id->filename, private_id->filename) == 0) |
| return 1; |
| for (i = 0; suffixes[i]; i++) { |
| slen = strlen(suffixes[i]); |
| if (len > slen && plen == len - slen && |
| strcmp(id->filename + (len - slen), suffixes[i]) == 0 && |
| memcmp(id->filename, private_id->filename, plen) == 0) |
| return 1; |
| } |
| return 0; |
| } |
| |
| static int |
| sign_and_send_pubkey(struct ssh *ssh, Identity *id) |
| { |
| Authctxt *authctxt = (Authctxt *)ssh->authctxt; |
| struct sshbuf *b = NULL; |
| Identity *private_id, *sign_id = NULL; |
| u_char *signature = NULL; |
| size_t slen = 0, skip = 0; |
| int r, fallback_sigtype, sent = 0; |
| char *alg = NULL, *fp = NULL; |
| const char *loc = ""; |
| |
| if ((fp = sshkey_fingerprint(id->key, options.fingerprint_hash, |
| SSH_FP_DEFAULT)) == NULL) |
| return 0; |
| |
| debug3("%s: %s %s", __func__, sshkey_type(id->key), fp); |
| |
| /* |
| * If the key is an certificate, try to find a matching private key |
| * and use it to complete the signature. |
| * If no such private key exists, fall back to trying the certificate |
| * key itself in case it has a private half already loaded. |
| * This will try to set sign_id to the private key that will perform |
| * the signature. |
| */ |
| if (sshkey_is_cert(id->key)) { |
| TAILQ_FOREACH(private_id, &authctxt->keys, next) { |
| if (sshkey_equal_public(id->key, private_id->key) && |
| id->key->type != private_id->key->type) { |
| sign_id = private_id; |
| break; |
| } |
| } |
| /* |
| * Exact key matches are preferred, but also allow |
| * filename matches for non-PKCS#11/agent keys that |
| * didn't load public keys. This supports the case |
| * of keeping just a private key file and public |
| * certificate on disk. |
| */ |
| if (sign_id == NULL && |
| !id->isprivate && id->agent_fd == -1 && |
| (id->key->flags & SSHKEY_FLAG_EXT) == 0) { |
| TAILQ_FOREACH(private_id, &authctxt->keys, next) { |
| if (private_id->key == NULL && |
| id_filename_matches(id, private_id)) { |
| sign_id = private_id; |
| break; |
| } |
| } |
| } |
| if (sign_id != NULL) { |
| debug2("%s: using private key \"%s\"%s for " |
| "certificate", __func__, id->filename, |
| id->agent_fd != -1 ? " from agent" : ""); |
| } else { |
| debug("%s: no separate private key for certificate " |
| "\"%s\"", __func__, id->filename); |
| } |
| } |
| |
| /* |
| * If the above didn't select another identity to do the signing |
| * then default to the one we started with. |
| */ |
| if (sign_id == NULL) |
| sign_id = id; |
| |
| /* assemble and sign data */ |
| for (fallback_sigtype = 0; fallback_sigtype <= 1; fallback_sigtype++) { |
| free(alg); |
| slen = 0; |
| signature = NULL; |
| if ((alg = key_sig_algorithm(fallback_sigtype ? NULL : ssh, |
| id->key)) == NULL) { |
| error("%s: no mutual signature supported", __func__); |
| goto out; |
| } |
| debug3("%s: signing using %s", __func__, alg); |
| |
| sshbuf_free(b); |
| if ((b = sshbuf_new()) == NULL) |
| fatal("%s: sshbuf_new failed", __func__); |
| if (datafellows & SSH_OLD_SESSIONID) { |
| if ((r = sshbuf_put(b, session_id2, |
| session_id2_len)) != 0) { |
| fatal("%s: sshbuf_put: %s", |
| __func__, ssh_err(r)); |
| } |
| } else { |
| if ((r = sshbuf_put_string(b, session_id2, |
| session_id2_len)) != 0) { |
| fatal("%s: sshbuf_put_string: %s", |
| __func__, ssh_err(r)); |
| } |
| } |
| skip = sshbuf_len(b); |
| if ((r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 || |
| (r = sshbuf_put_cstring(b, authctxt->server_user)) != 0 || |
| (r = sshbuf_put_cstring(b, authctxt->service)) != 0 || |
| (r = sshbuf_put_cstring(b, authctxt->method->name)) != 0 || |
| (r = sshbuf_put_u8(b, 1)) != 0 || |
| (r = sshbuf_put_cstring(b, alg)) != 0 || |
| (r = sshkey_puts(id->key, b)) != 0) { |
| fatal("%s: assemble signed data: %s", |
| __func__, ssh_err(r)); |
| } |
| |
| /* generate signature */ |
| r = identity_sign(sign_id, &signature, &slen, |
| sshbuf_ptr(b), sshbuf_len(b), datafellows, alg); |
| if (r == 0) |
| break; |
| else if (r == SSH_ERR_KEY_NOT_FOUND) |
| goto out; /* soft failure */ |
| else if (r == SSH_ERR_SIGN_ALG_UNSUPPORTED && |
| !fallback_sigtype) { |
| if (sign_id->agent_fd != -1) |
| loc = "agent "; |
| else if ((sign_id->key->flags & SSHKEY_FLAG_EXT) != 0) |
| loc = "token "; |
| logit("%skey %s %s returned incorrect signature type", |
| loc, sshkey_type(id->key), fp); |
| continue; |
| } |
| error("%s: signing failed: %s", __func__, ssh_err(r)); |
| goto out; |
| } |
| if (slen == 0 || signature == NULL) /* shouldn't happen */ |
| fatal("%s: no signature", __func__); |
| |
| /* append signature */ |
| if ((r = sshbuf_put_string(b, signature, slen)) != 0) |
| fatal("%s: append signature: %s", __func__, ssh_err(r)); |
| |
| #ifdef DEBUG_PK |
| sshbuf_dump(b, stderr); |
| #endif |
| /* skip session id and packet type */ |
| if ((r = sshbuf_consume(b, skip + 1)) != 0) |
| fatal("%s: consume: %s", __func__, ssh_err(r)); |
| |
| /* put remaining data from buffer into packet */ |
| if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || |
| (r = sshpkt_putb(ssh, b)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) |
| fatal("%s: enqueue request: %s", __func__, ssh_err(r)); |
| |
| /* success */ |
| sent = 1; |
| |
| out: |
| free(fp); |
| free(alg); |
| sshbuf_free(b); |
| freezero(signature, slen); |
| return sent; |
| } |
| |
| static int |
| send_pubkey_test(struct ssh *ssh, Identity *id) |
| { |
| Authctxt *authctxt = (Authctxt *)ssh->authctxt; |
| u_char *blob = NULL; |
| char *alg = NULL; |
| size_t bloblen; |
| u_int have_sig = 0; |
| int sent = 0, r; |
| |
| if ((alg = key_sig_algorithm(ssh, id->key)) == NULL) { |
| debug("%s: no mutual signature algorithm", __func__); |
| goto out; |
| } |
| |
| if ((r = sshkey_to_blob(id->key, &blob, &bloblen)) != 0) { |
| /* we cannot handle this key */ |
| debug3("%s: cannot handle key", __func__); |
| goto out; |
| } |
| /* register callback for USERAUTH_PK_OK message */ |
| ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); |
| |
| if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || |
| (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || |
| (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || |
| (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || |
| (r = sshpkt_put_u8(ssh, have_sig)) != 0 || |
| (r = sshpkt_put_cstring(ssh, alg)) != 0 || |
| (r = sshpkt_put_string(ssh, blob, bloblen)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) |
| fatal("%s: %s", __func__, ssh_err(r)); |
| sent = 1; |
| |
| out: |
| free(alg); |
| free(blob); |
| return sent; |
| } |
| |
| static struct sshkey * |
| load_identity_file(Identity *id) |
| { |
| struct sshkey *private = NULL; |
| char prompt[300], *passphrase, *comment; |
| int r, perm_ok = 0, quit = 0, i; |
| struct stat st; |
| |
| if (stat(id->filename, &st) < 0) { |
| (id->userprovided ? logit : debug3)("no such identity: %s: %s", |
| id->filename, strerror(errno)); |
| return NULL; |
| } |
| snprintf(prompt, sizeof prompt, |
| "Enter passphrase for key '%.100s': ", id->filename); |
| for (i = 0; i <= options.number_of_password_prompts; i++) { |
| if (i == 0) |
| passphrase = ""; |
| else { |
| passphrase = read_passphrase(prompt, 0); |
| if (*passphrase == '\0') { |
| debug2("no passphrase given, try next key"); |
| free(passphrase); |
| break; |
| } |
| } |
| switch ((r = sshkey_load_private_type(KEY_UNSPEC, id->filename, |
| passphrase, &private, &comment, &perm_ok))) { |
| case 0: |
| break; |
| case SSH_ERR_KEY_WRONG_PASSPHRASE: |
| if (options.batch_mode) { |
| quit = 1; |
| break; |
| } |
| if (i != 0) |
| debug2("bad passphrase given, try again..."); |
| break; |
| case SSH_ERR_SYSTEM_ERROR: |
| if (errno == ENOENT) { |
| debug2("Load key \"%s\": %s", |
| id->filename, ssh_err(r)); |
| quit = 1; |
| break; |
| } |
| /* FALLTHROUGH */ |
| default: |
| error("Load key \"%s\": %s", id->filename, ssh_err(r)); |
| quit = 1; |
| break; |
| } |
| if (!quit && private != NULL && id->agent_fd == -1 && |
| !(id->key && id->isprivate)) |
| maybe_add_key_to_agent(id->filename, private, comment, |
| passphrase); |
| if (i > 0) |
| freezero(passphrase, strlen(passphrase)); |
| free(comment); |
| if (private != NULL || quit) |
| break; |
| } |
| return private; |
| } |
| |
| static int |
| key_type_allowed_by_config(struct sshkey *key) |
| { |
| if (match_pattern_list(sshkey_ssh_name(key), |
| options.pubkey_key_types, 0) == 1) |
| return 1; |
| |
| /* RSA keys/certs might be allowed by alternate signature types */ |
| switch (key->type) { |
| case KEY_RSA: |
| if (match_pattern_list("rsa-sha2-512", |
| options.pubkey_key_types, 0) == 1) |
| return 1; |
| if (match_pattern_list("rsa-sha2-256", |
| options.pubkey_key_types, 0) == 1) |
| return 1; |
| break; |
| case KEY_RSA_CERT: |
| if (match_pattern_list("rsa-sha2-512-cert-v01@openssh.com", |
| options.pubkey_key_types, 0) == 1) |
| return 1; |
| if (match_pattern_list("rsa-sha2-256-cert-v01@openssh.com", |
| options.pubkey_key_types, 0) == 1) |
| return 1; |
| break; |
| } |
| return 0; |
| } |
| |
| |
| /* |
| * try keys in the following order: |
| * 1. certificates listed in the config file |
| * 2. other input certificates |
| * 3. agent keys that are found in the config file |
| * 4. other agent keys |
| * 5. keys that are only listed in the config file |
| */ |
| static void |
| pubkey_prepare(Authctxt *authctxt) |
| { |
| struct identity *id, *id2, *tmp; |
| struct idlist agent, files, *preferred; |
| struct sshkey *key; |
| int agent_fd = -1, i, r, found; |
| size_t j; |
| struct ssh_identitylist *idlist; |
| char *ident; |
| |
| TAILQ_INIT(&agent); /* keys from the agent */ |
| TAILQ_INIT(&files); /* keys from the config file */ |
| preferred = &authctxt->keys; |
| TAILQ_INIT(preferred); /* preferred order of keys */ |
| |
| /* list of keys stored in the filesystem and PKCS#11 */ |
| for (i = 0; i < options.num_identity_files; i++) { |
| key = options.identity_keys[i]; |
| if (key && key->cert && key->cert->type != SSH2_CERT_TYPE_USER) |
| continue; |
| options.identity_keys[i] = NULL; |
| id = xcalloc(1, sizeof(*id)); |
| id->agent_fd = -1; |
| id->key = key; |
| id->filename = xstrdup(options.identity_files[i]); |
| id->userprovided = options.identity_file_userprovided[i]; |
| TAILQ_INSERT_TAIL(&files, id, next); |
| } |
| /* list of certificates specified by user */ |
| for (i = 0; i < options.num_certificate_files; i++) { |
| key = options.certificates[i]; |
| if (!sshkey_is_cert(key) || key->cert == NULL || |
| key->cert->type != SSH2_CERT_TYPE_USER) |
| continue; |
| id = xcalloc(1, sizeof(*id)); |
| id->agent_fd = -1; |
| id->key = key; |
| id->filename = xstrdup(options.certificate_files[i]); |
| id->userprovided = options.certificate_file_userprovided[i]; |
| TAILQ_INSERT_TAIL(preferred, id, next); |
| } |
| /* list of keys supported by the agent */ |
| if ((r = ssh_get_authentication_socket(&agent_fd)) != 0) { |
| if (r != SSH_ERR_AGENT_NOT_PRESENT) |
| debug("%s: ssh_get_authentication_socket: %s", |
| __func__, ssh_err(r)); |
| } else if ((r = ssh_fetch_identitylist(agent_fd, &idlist)) != 0) { |
| if (r != SSH_ERR_AGENT_NO_IDENTITIES) |
| debug("%s: ssh_fetch_identitylist: %s", |
| __func__, ssh_err(r)); |
| close(agent_fd); |
| } else { |
| for (j = 0; j < idlist->nkeys; j++) { |
| found = 0; |
| TAILQ_FOREACH(id, &files, next) { |
| /* |
| * agent keys from the config file are |
| * preferred |
| */ |
| if (sshkey_equal(idlist->keys[j], id->key)) { |
| TAILQ_REMOVE(&files, id, next); |
| TAILQ_INSERT_TAIL(preferred, id, next); |
| id->agent_fd = agent_fd; |
| found = 1; |
| break; |
| } |
| } |
| if (!found && !options.identities_only) { |
| id = xcalloc(1, sizeof(*id)); |
| /* XXX "steals" key/comment from idlist */ |
| id->key = idlist->keys[j]; |
| id->filename = idlist->comments[j]; |
| idlist->keys[j] = NULL; |
| idlist->comments[j] = NULL; |
| id->agent_fd = agent_fd; |
| TAILQ_INSERT_TAIL(&agent, id, next); |
| } |
| } |
| ssh_free_identitylist(idlist); |
| /* append remaining agent keys */ |
| for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { |
| TAILQ_REMOVE(&agent, id, next); |
| TAILQ_INSERT_TAIL(preferred, id, next); |
| } |
| authctxt->agent_fd = agent_fd; |
| } |
| /* Prefer PKCS11 keys that are explicitly listed */ |
| TAILQ_FOREACH_SAFE(id, &files, next, tmp) { |
| if (id->key == NULL || (id->key->flags & SSHKEY_FLAG_EXT) == 0) |
| continue; |
| found = 0; |
| TAILQ_FOREACH(id2, &files, next) { |
| if (id2->key == NULL || |
| (id2->key->flags & SSHKEY_FLAG_EXT) == 0) |
| continue; |
| if (sshkey_equal(id->key, id2->key)) { |
| TAILQ_REMOVE(&files, id, next); |
| TAILQ_INSERT_TAIL(preferred, id, next); |
| found = 1; |
| break; |
| } |
| } |
| /* If IdentitiesOnly set and key not found then don't use it */ |
| if (!found && options.identities_only) { |
| TAILQ_REMOVE(&files, id, next); |
| freezero(id, sizeof(*id)); |
| } |
| } |
| /* append remaining keys from the config file */ |
| for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { |
| TAILQ_REMOVE(&files, id, next); |
| TAILQ_INSERT_TAIL(preferred, id, next); |
| } |
| /* finally, filter by PubkeyAcceptedKeyTypes */ |
| TAILQ_FOREACH_SAFE(id, preferred, next, id2) { |
| if (id->key != NULL && !key_type_allowed_by_config(id->key)) { |
| debug("Skipping %s key %s - " |
| "not in PubkeyAcceptedKeyTypes", |
| sshkey_ssh_name(id->key), id->filename); |
| TAILQ_REMOVE(preferred, id, next); |
| sshkey_free(id->key); |
| free(id->filename); |
| memset(id, 0, sizeof(*id)); |
| continue; |
| } |
| } |
| /* List the keys we plan on using */ |
| TAILQ_FOREACH_SAFE(id, preferred, next, id2) { |
| ident = format_identity(id); |
| debug("Will attempt key: %s", ident); |
| free(ident); |
| } |
| debug2("%s: done", __func__); |
| } |
| |
| static void |
| pubkey_cleanup(struct ssh *ssh) |
| { |
| Authctxt *authctxt = (Authctxt *)ssh->authctxt; |
| Identity *id; |
| |
| if (authctxt->agent_fd != -1) { |
| ssh_close_authentication_socket(authctxt->agent_fd); |
| authctxt->agent_fd = -1; |
| } |
| for (id = TAILQ_FIRST(&authctxt->keys); id; |
| id = TAILQ_FIRST(&authctxt->keys)) { |
| TAILQ_REMOVE(&authctxt->keys, id, next); |
| sshkey_free(id->key); |
| free(id->filename); |
| free(id); |
| } |
| } |
| |
| static void |
| pubkey_reset(Authctxt *authctxt) |
| { |
| Identity *id; |
| |
| TAILQ_FOREACH(id, &authctxt->keys, next) |
| id->tried = 0; |
| } |
| |
| static int |
| try_identity(Identity *id) |
| { |
| if (!id->key) |
| return (0); |
| if (sshkey_type_plain(id->key->type) == KEY_RSA && |
| (datafellows & SSH_BUG_RSASIGMD5) != 0) { |
| debug("Skipped %s key %s for RSA/MD5 server", |
| sshkey_type(id->key), id->filename); |
| return (0); |
| } |
| return 1; |
| } |
| |
| static int |
| userauth_pubkey(struct ssh *ssh) |
| { |
| Authctxt *authctxt = (Authctxt *)ssh->authctxt; |
| Identity *id; |
| int sent = 0; |
| char *ident; |
| |
| while ((id = TAILQ_FIRST(&authctxt->keys))) { |
| if (id->tried++) |
| return (0); |
| /* move key to the end of the queue */ |
| TAILQ_REMOVE(&authctxt->keys, id, next); |
| TAILQ_INSERT_TAIL(&authctxt->keys, id, next); |
| /* |
| * send a test message if we have the public key. for |
| * encrypted keys we cannot do this and have to load the |
| * private key instead |
| */ |
| if (id->key != NULL) { |
| if (try_identity(id)) { |
| ident = format_identity(id); |
| debug("Offering public key: %s", ident); |
| free(ident); |
| sent = send_pubkey_test(ssh, id); |
| } |
| } else { |
| debug("Trying private key: %s", id->filename); |
| id->key = load_identity_file(id); |
| if (id->key != NULL) { |
| if (try_identity(id)) { |
| id->isprivate = 1; |
| sent = sign_and_send_pubkey(ssh, id); |
| } |
| sshkey_free(id->key); |
| id->key = NULL; |
| id->isprivate = 0; |
| } |
| } |
| if (sent) |
| return (sent); |
| } |
| return (0); |
| } |
| |
| /* |
| * Send userauth request message specifying keyboard-interactive method. |
| */ |
| static int |
| userauth_kbdint(struct ssh *ssh) |
| { |
| Authctxt *authctxt = (Authctxt *)ssh->authctxt; |
| int r; |
| |
| if (authctxt->attempt_kbdint++ >= options.number_of_password_prompts) |
| return 0; |
| /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ |
| if (authctxt->attempt_kbdint > 1 && !authctxt->info_req_seen) { |
| debug3("userauth_kbdint: disable: no info_req_seen"); |
| ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); |
| return 0; |
| } |
| |
| debug2("userauth_kbdint"); |
| if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || |
| (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || |
| (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || |
| (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || |
| (r = sshpkt_put_cstring(ssh, "")) != 0 || /* lang */ |
| (r = sshpkt_put_cstring(ssh, options.kbd_interactive_devices ? |
| options.kbd_interactive_devices : "")) != 0 || |
| (r = sshpkt_send(ssh)) != 0) |
| fatal("%s: %s", __func__, ssh_err(r)); |
| |
| ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); |
| return 1; |
| } |
| |
| /* |
| * parse INFO_REQUEST, prompt user and send INFO_RESPONSE |
| */ |
| static int |
| input_userauth_info_req(int type, u_int32_t seq, struct ssh *ssh) |
| { |
| Authctxt *authctxt = ssh->authctxt; |
| char *name = NULL, *inst = NULL, *lang = NULL, *prompt = NULL; |
| char *response = NULL; |
| u_char echo = 0; |
| u_int num_prompts, i; |
| int r; |
| |
| debug2("input_userauth_info_req"); |
| |
| if (authctxt == NULL) |
| fatal("input_userauth_info_req: no authentication context"); |
| |
| authctxt->info_req_seen = 1; |
| |
| if ((r = sshpkt_get_cstring(ssh, &name, NULL)) != 0 || |
| (r = sshpkt_get_cstring(ssh, &inst, NULL)) != 0 || |
| (r = sshpkt_get_cstring(ssh, &lang, NULL)) != 0) |
| goto out; |
| if (strlen(name) > 0) |
| logit("%s", name); |
| if (strlen(inst) > 0) |
| logit("%s", inst); |
| |
| if ((r = sshpkt_get_u32(ssh, &num_prompts)) != 0) |
| goto out; |
| /* |
| * 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. |
| */ |
| if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE)) != 0 || |
| (r = sshpkt_put_u32(ssh, num_prompts)) != 0) |
| goto out; |
| |
| debug2("input_userauth_info_req: num_prompts %d", num_prompts); |
| for (i = 0; i < num_prompts; i++) { |
| if ((r = sshpkt_get_cstring(ssh, &prompt, NULL)) != 0 || |
| (r = sshpkt_get_u8(ssh, &echo)) != 0) |
| goto out; |
| response = read_passphrase(prompt, echo ? RP_ECHO : 0); |
| if ((r = sshpkt_put_cstring(ssh, response)) != 0) |
| goto out; |
| freezero(response, strlen(response)); |
| free(prompt); |
| response = prompt = NULL; |
| } |
| /* done with parsing incoming message. */ |
| if ((r = sshpkt_get_end(ssh)) != 0 || |
| (r = sshpkt_add_padding(ssh, 64)) != 0) |
| goto out; |
| r = sshpkt_send(ssh); |
| out: |
| if (response) |
| freezero(response, strlen(response)); |
| free(prompt); |
| free(name); |
| free(inst); |
| free(lang); |
| return r; |
| } |
| |
| static int |
| ssh_keysign(struct ssh *ssh, struct sshkey *key, u_char **sigp, size_t *lenp, |
| const u_char *data, size_t datalen) |
| { |
| struct sshbuf *b; |
| struct stat st; |
| pid_t pid; |
| int r, to[2], from[2], status; |
| int sock = ssh_packet_get_connection_in(ssh); |
| u_char rversion = 0, version = 2; |
| void (*osigchld)(int); |
| |
| *sigp = NULL; |
| *lenp = 0; |
| |
| if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { |
| error("%s: not installed: %s", __func__, strerror(errno)); |
| return -1; |
| } |
| if (fflush(stdout) != 0) { |
| error("%s: fflush: %s", __func__, strerror(errno)); |
| return -1; |
| } |
| if (pipe(to) < 0) { |
| error("%s: pipe: %s", __func__, strerror(errno)); |
| return -1; |
| } |
| if (pipe(from) < 0) { |
| error("%s: pipe: %s", __func__, strerror(errno)); |
| return -1; |
| } |
| if ((pid = fork()) < 0) { |
| error("%s: fork: %s", __func__, strerror(errno)); |
| return -1; |
| } |
| osigchld = signal(SIGCHLD, SIG_DFL); |
| if (pid == 0) { |
| close(from[0]); |
| if (dup2(from[1], STDOUT_FILENO) < 0) |
| fatal("%s: dup2: %s", __func__, strerror(errno)); |
| close(to[1]); |
| if (dup2(to[0], STDIN_FILENO) < 0) |
| fatal("%s: dup2: %s", __func__, strerror(errno)); |
| close(from[1]); |
| close(to[0]); |
| |
| if (dup2(sock, STDERR_FILENO + 1) < 0) |
| fatal("%s: dup2: %s", __func__, strerror(errno)); |
| sock = STDERR_FILENO + 1; |
| fcntl(sock, F_SETFD, 0); /* keep the socket on exec */ |
| closefrom(sock + 1); |
| |
| debug3("%s: [child] pid=%ld, exec %s", |
| __func__, (long)getpid(), _PATH_SSH_KEY_SIGN); |
| execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *)NULL); |
| fatal("%s: exec(%s): %s", __func__, _PATH_SSH_KEY_SIGN, |
| strerror(errno)); |
| } |
| close(from[1]); |
| close(to[0]); |
| sock = STDERR_FILENO + 1; |
| |
| if ((b = sshbuf_new()) == NULL) |
| fatal("%s: sshbuf_new failed", __func__); |
| /* send # of sock, data to be signed */ |
| if ((r = sshbuf_put_u32(b, sock)) != 0 || |
| (r = sshbuf_put_string(b, data, datalen)) != 0) |
| fatal("%s: buffer error: %s", __func__, ssh_err(r)); |
| if (ssh_msg_send(to[1], version, b) == -1) |
| fatal("%s: couldn't send request", __func__); |
| sshbuf_reset(b); |
| r = ssh_msg_recv(from[0], b); |
| close(from[0]); |
| close(to[1]); |
| if (r < 0) { |
| error("%s: no reply", __func__); |
| goto fail; |
| } |
| |
| errno = 0; |
| while (waitpid(pid, &status, 0) < 0) { |
| if (errno != EINTR) { |
| error("%s: waitpid %ld: %s", |
| __func__, (long)pid, strerror(errno)); |
| goto fail; |
| } |
| } |
| if (!WIFEXITED(status)) { |
| error("%s: exited abnormally", __func__); |
| goto fail; |
| } |
| if (WEXITSTATUS(status) != 0) { |
| error("%s: exited with status %d", |
| __func__, WEXITSTATUS(status)); |
| goto fail; |
| } |
| if ((r = sshbuf_get_u8(b, &rversion)) != 0) { |
| error("%s: buffer error: %s", __func__, ssh_err(r)); |
| goto fail; |
| } |
| if (rversion != version) { |
| error("%s: bad version", __func__); |
| goto fail; |
| } |
| if ((r = sshbuf_get_string(b, sigp, lenp)) != 0) { |
| error("%s: buffer error: %s", __func__, ssh_err(r)); |
| fail: |
| signal(SIGCHLD, osigchld); |
| sshbuf_free(b); |
| return -1; |
| } |
| signal(SIGCHLD, osigchld); |
| sshbuf_free(b); |
| |
| return 0; |
| } |
| |
| static int |
| userauth_hostbased(struct ssh *ssh) |
| { |
| Authctxt *authctxt = (Authctxt *)ssh->authctxt; |
| struct sshkey *private = NULL; |
| struct sshbuf *b = NULL; |
| u_char *sig = NULL, *keyblob = NULL; |
| char *fp = NULL, *chost = NULL, *lname = NULL; |
| size_t siglen = 0, keylen = 0; |
| int i, r, success = 0; |
| |
| if (authctxt->ktypes == NULL) { |
| authctxt->oktypes = xstrdup(options.hostbased_key_types); |
| authctxt->ktypes = authctxt->oktypes; |
| } |
| |
| /* |
| * Work through each listed type pattern in HostbasedKeyTypes, |
| * trying each hostkey that matches the type in turn. |
| */ |
| for (;;) { |
| if (authctxt->active_ktype == NULL) |
| authctxt->active_ktype = strsep(&authctxt->ktypes, ","); |
| if (authctxt->active_ktype == NULL || |
| *authctxt->active_ktype == '\0') |
| break; |
| debug3("%s: trying key type %s", __func__, |
| authctxt->active_ktype); |
| |
| /* check for a useful key */ |
| private = NULL; |
| for (i = 0; i < authctxt->sensitive->nkeys; i++) { |
| if (authctxt->sensitive->keys[i] == NULL || |
| authctxt->sensitive->keys[i]->type == KEY_UNSPEC) |
| continue; |
| if (match_pattern_list( |
| sshkey_ssh_name(authctxt->sensitive->keys[i]), |
| authctxt->active_ktype, 0) != 1) |
| continue; |
| /* we take and free the key */ |
| private = authctxt->sensitive->keys[i]; |
| authctxt->sensitive->keys[i] = NULL; |
| break; |
| } |
| /* Found one */ |
| if (private != NULL) |
| break; |
| /* No more keys of this type; advance */ |
| authctxt->active_ktype = NULL; |
| } |
| if (private == NULL) { |
| free(authctxt->oktypes); |
| authctxt->oktypes = authctxt->ktypes = NULL; |
| authctxt->active_ktype = NULL; |
| debug("No more client hostkeys for hostbased authentication."); |
| goto out; |
| } |
| |
| if ((fp = sshkey_fingerprint(private, options.fingerprint_hash, |
| SSH_FP_DEFAULT)) == NULL) { |
| error("%s: sshkey_fingerprint failed", __func__); |
| goto out; |
| } |
| debug("%s: trying hostkey %s %s", |
| __func__, sshkey_ssh_name(private), fp); |
| |
| /* figure out a name for the client host */ |
| lname = get_local_name(ssh_packet_get_connection_in(ssh)); |
| if (lname == NULL) { |
| error("%s: cannot get local ipaddr/name", __func__); |
| goto out; |
| } |
| |
| /* XXX sshbuf_put_stringf? */ |
| xasprintf(&chost, "%s.", lname); |
| debug2("%s: chost %s", __func__, chost); |
| |
| /* construct data */ |
| if ((b = sshbuf_new()) == NULL) { |
| error("%s: sshbuf_new failed", __func__); |
| goto out; |
| } |
| if ((r = sshkey_to_blob(private, &keyblob, &keylen)) != 0) { |
| error("%s: sshkey_to_blob: %s", __func__, ssh_err(r)); |
| goto out; |
| } |
| if ((r = sshbuf_put_string(b, session_id2, session_id2_len)) != 0 || |
| (r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 || |
| (r = sshbuf_put_cstring(b, authctxt->server_user)) != 0 || |
| (r = sshbuf_put_cstring(b, authctxt->service)) != 0 || |
| (r = sshbuf_put_cstring(b, authctxt->method->name)) != 0 || |
| (r = sshbuf_put_cstring(b, sshkey_ssh_name(private))) != 0 || |
| (r = sshbuf_put_string(b, keyblob, keylen)) != 0 || |
| (r = sshbuf_put_cstring(b, chost)) != 0 || |
| (r = sshbuf_put_cstring(b, authctxt->local_user)) != 0) { |
| error("%s: buffer error: %s", __func__, ssh_err(r)); |
| goto out; |
| } |
| |
| #ifdef DEBUG_PK |
| sshbuf_dump(b, stderr); |
| #endif |
| if ((r = ssh_keysign(ssh, private, &sig, &siglen, |
| sshbuf_ptr(b), sshbuf_len(b))) != 0) { |
| error("sign using hostkey %s %s failed", |
| sshkey_ssh_name(private), fp); |
| goto out; |
| } |
| if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || |
| (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || |
| (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || |
| (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || |
| (r = sshpkt_put_cstring(ssh, sshkey_ssh_name(private))) != 0 || |
| (r = sshpkt_put_string(ssh, keyblob, keylen)) != 0 || |
| (r = sshpkt_put_cstring(ssh, chost)) != 0 || |
| (r = sshpkt_put_cstring(ssh, authctxt->local_user)) != 0 || |
| (r = sshpkt_put_string(ssh, sig, siglen)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) { |
| error("%s: packet error: %s", __func__, ssh_err(r)); |
| goto out; |
| } |
| success = 1; |
| |
| out: |
| if (sig != NULL) |
| freezero(sig, siglen); |
| free(keyblob); |
| free(lname); |
| free(fp); |
| free(chost); |
| sshkey_free(private); |
| sshbuf_free(b); |
| |
| return success; |
| } |
| |
| /* find auth method */ |
| |
| /* |
| * given auth method name, if configurable options permit this method fill |
| * in auth_ident field and return true, otherwise return false. |
| */ |
| static 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; |
| } |
| |
| static 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; |
| } |
| |
| /* XXX internal state */ |
| static Authmethod *current = NULL; |
| static char *supported = NULL; |
| static char *preferred = 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. |
| */ |
| static Authmethod * |
| authmethod_get(char *authlist) |
| { |
| char *name = NULL; |
| u_int next; |
| |
| /* Use a suitable default if we're passed a nil list. */ |
| if (authlist == NULL || strlen(authlist) == 0) |
| authlist = options.preferred_authentications; |
| |
| if (supported == NULL || strcmp(authlist, supported) != 0) { |
| debug3("start over, passed a different list %s", authlist); |
| free(supported); |
| supported = xstrdup(authlist); |
| preferred = options.preferred_authentications; |
| debug3("preferred %s", preferred); |
| current = NULL; |
| } else if (current != NULL && authmethod_is_enabled(current)) |
| return current; |
| |
| for (;;) { |
| if ((name = match_list(preferred, supported, &next)) == NULL) { |
| debug("No more authentication methods to try."); |
| current = NULL; |
| return NULL; |
| } |
| preferred += next; |
| debug3("authmethod_lookup %s", name); |
| debug3("remaining preferred: %s", preferred); |
| if ((current = authmethod_lookup(name)) != NULL && |
| authmethod_is_enabled(current)) { |
| debug3("authmethod_is_enabled %s", name); |
| debug("Next authentication method: %s", name); |
| free(name); |
| return current; |
| } |
| free(name); |
| } |
| } |
| |
| static char * |
| authmethods_get(void) |
| { |
| Authmethod *method = NULL; |
| struct sshbuf *b; |
| char *list; |
| int r; |
| |
| if ((b = sshbuf_new()) == NULL) |
| fatal("%s: sshbuf_new failed", __func__); |
| for (method = authmethods; method->name != NULL; method++) { |
| if (authmethod_is_enabled(method)) { |
| if ((r = sshbuf_putf(b, "%s%s", |
| sshbuf_len(b) ? "," : "", method->name)) != 0) |
| fatal("%s: buffer error: %s", |
| __func__, ssh_err(r)); |
| } |
| } |
| if ((list = sshbuf_dup_string(b)) == NULL) |
| fatal("%s: sshbuf_dup_string failed", __func__); |
| sshbuf_free(b); |
| return list; |
| } |