| /* $OpenBSD: auth2.c,v 1.148 2018/07/09 21:35:50 markus Exp $ */ |
| /* |
| * 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" |
| |
| #include <sys/types.h> |
| #include <sys/stat.h> |
| #include <sys/uio.h> |
| |
| #include <fcntl.h> |
| #include <limits.h> |
| #include <pwd.h> |
| #include <stdarg.h> |
| #include <string.h> |
| #include <unistd.h> |
| |
| #include "atomicio.h" |
| #include "xmalloc.h" |
| #include "ssh2.h" |
| #include "packet.h" |
| #include "log.h" |
| #include "sshbuf.h" |
| #include "misc.h" |
| #include "servconf.h" |
| #include "compat.h" |
| #include "key.h" |
| #include "hostfile.h" |
| #include "auth.h" |
| #include "dispatch.h" |
| #include "pathnames.h" |
| #include "buffer.h" |
| |
| #ifdef GSSAPI |
| #include "ssh-gss.h" |
| #endif |
| #include "monitor_wrap.h" |
| #include "ssherr.h" |
| #include "digest.h" |
| |
| /* import */ |
| extern ServerOptions options; |
| extern u_char *session_id2; |
| extern u_int session_id2_len; |
| extern Buffer loginmsg; |
| |
| /* methods */ |
| |
| extern Authmethod method_none; |
| extern Authmethod method_pubkey; |
| extern Authmethod method_passwd; |
| extern Authmethod method_kbdint; |
| extern Authmethod method_hostbased; |
| #ifdef GSSAPI |
| extern Authmethod method_gssapi; |
| #endif |
| |
| Authmethod *authmethods[] = { |
| &method_none, |
| &method_pubkey, |
| #ifdef GSSAPI |
| &method_gssapi, |
| #endif |
| &method_passwd, |
| &method_kbdint, |
| &method_hostbased, |
| NULL |
| }; |
| |
| /* protocol */ |
| |
| static int input_service_request(int, u_int32_t, struct ssh *); |
| static int input_userauth_request(int, u_int32_t, struct ssh *); |
| |
| /* helper */ |
| static Authmethod *authmethod_lookup(Authctxt *, const char *); |
| static char *authmethods_get(Authctxt *authctxt); |
| |
| #define MATCH_NONE 0 /* method or submethod mismatch */ |
| #define MATCH_METHOD 1 /* method matches (no submethod specified) */ |
| #define MATCH_BOTH 2 /* method and submethod match */ |
| #define MATCH_PARTIAL 3 /* method matches, submethod can't be checked */ |
| static int list_starts_with(const char *, const char *, const char *); |
| |
| char * |
| auth2_read_banner(void) |
| { |
| struct stat st; |
| char *banner = NULL; |
| size_t len, n; |
| int fd; |
| |
| if ((fd = open(options.banner, O_RDONLY)) == -1) |
| return (NULL); |
| if (fstat(fd, &st) == -1) { |
| close(fd); |
| return (NULL); |
| } |
| if (st.st_size <= 0 || st.st_size > 1*1024*1024) { |
| close(fd); |
| return (NULL); |
| } |
| |
| len = (size_t)st.st_size; /* truncate */ |
| banner = xmalloc(len + 1); |
| n = atomicio(read, fd, banner, len); |
| close(fd); |
| |
| if (n != len) { |
| free(banner); |
| return (NULL); |
| } |
| banner[n] = '\0'; |
| |
| return (banner); |
| } |
| |
| void |
| userauth_send_banner(const char *msg) |
| { |
| packet_start(SSH2_MSG_USERAUTH_BANNER); |
| packet_put_cstring(msg); |
| packet_put_cstring(""); /* language, unused */ |
| packet_send(); |
| debug("%s: sent", __func__); |
| } |
| |
| static void |
| userauth_banner(void) |
| { |
| char *banner = NULL; |
| |
| if (options.banner == NULL) |
| return; |
| |
| if ((banner = PRIVSEP(auth2_read_banner())) == NULL) |
| goto done; |
| userauth_send_banner(banner); |
| |
| done: |
| free(banner); |
| } |
| |
| /* |
| * loop until authctxt->success == TRUE |
| */ |
| void |
| do_authentication2(Authctxt *authctxt) |
| { |
| struct ssh *ssh = active_state; /* XXX */ |
| ssh->authctxt = authctxt; /* XXX move to caller */ |
| ssh_dispatch_init(ssh, &dispatch_protocol_error); |
| ssh_dispatch_set(ssh, SSH2_MSG_SERVICE_REQUEST, &input_service_request); |
| ssh_dispatch_run_fatal(ssh, DISPATCH_BLOCK, &authctxt->success); |
| ssh->authctxt = NULL; |
| } |
| |
| /*ARGSUSED*/ |
| static int |
| input_service_request(int type, u_int32_t seq, struct ssh *ssh) |
| { |
| Authctxt *authctxt = ssh->authctxt; |
| u_int len; |
| int acceptit = 0; |
| char *service = packet_get_cstring(&len); |
| packet_check_eom(); |
| |
| if (authctxt == NULL) |
| fatal("input_service_request: no authctxt"); |
| |
| if (strcmp(service, "ssh-userauth") == 0) { |
| if (!authctxt->success) { |
| acceptit = 1; |
| /* now we can handle user-auth requests */ |
| ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request); |
| } |
| } |
| /* XXX all other service requests are denied */ |
| |
| if (acceptit) { |
| packet_start(SSH2_MSG_SERVICE_ACCEPT); |
| packet_put_cstring(service); |
| packet_send(); |
| packet_write_wait(); |
| } else { |
| debug("bad service request %s", service); |
| packet_disconnect("bad service request %s", service); |
| } |
| free(service); |
| return 0; |
| } |
| |
| #define MIN_FAIL_DELAY_SECONDS 0.005 |
| static double |
| user_specific_delay(const char *user) |
| { |
| char b[512]; |
| size_t len = ssh_digest_bytes(SSH_DIGEST_SHA512); |
| u_char *hash = xmalloc(len); |
| double delay; |
| |
| (void)snprintf(b, sizeof b, "%llu%s", |
| (unsigned long long)options.timing_secret, user); |
| if (ssh_digest_memory(SSH_DIGEST_SHA512, b, strlen(b), hash, len) != 0) |
| fatal("%s: ssh_digest_memory", __func__); |
| /* 0-4.2 ms of delay */ |
| delay = (double)PEEK_U32(hash) / 1000 / 1000 / 1000 / 1000; |
| freezero(hash, len); |
| debug3("%s: user specific delay %0.3lfms", __func__, delay/1000); |
| return MIN_FAIL_DELAY_SECONDS + delay; |
| } |
| |
| static void |
| ensure_minimum_time_since(double start, double seconds) |
| { |
| struct timespec ts; |
| double elapsed = monotime_double() - start, req = seconds, remain; |
| |
| /* if we've already passed the requested time, scale up */ |
| while ((remain = seconds - elapsed) < 0.0) |
| seconds *= 2; |
| |
| ts.tv_sec = remain; |
| ts.tv_nsec = (remain - ts.tv_sec) * 1000000000; |
| debug3("%s: elapsed %0.3lfms, delaying %0.3lfms (requested %0.3lfms)", |
| __func__, elapsed*1000, remain*1000, req*1000); |
| nanosleep(&ts, NULL); |
| } |
| |
| /*ARGSUSED*/ |
| static int |
| input_userauth_request(int type, u_int32_t seq, struct ssh *ssh) |
| { |
| Authctxt *authctxt = ssh->authctxt; |
| Authmethod *m = NULL; |
| char *user, *service, *method, *style = NULL; |
| int authenticated = 0; |
| double tstart = monotime_double(); |
| |
| if (authctxt == NULL) |
| fatal("input_userauth_request: no authctxt"); |
| |
| user = packet_get_cstring(NULL); |
| service = packet_get_cstring(NULL); |
| method = packet_get_cstring(NULL); |
| debug("userauth-request for user %s service %s method %s", user, service, method); |
| debug("attempt %d failures %d", authctxt->attempt, authctxt->failures); |
| |
| if ((style = strchr(user, ':')) != NULL) |
| *style++ = 0; |
| |
| if (authctxt->attempt++ == 0) { |
| /* setup auth context */ |
| authctxt->pw = PRIVSEP(getpwnamallow(user)); |
| authctxt->user = xstrdup(user); |
| if (authctxt->pw && strcmp(service, "ssh-connection")==0) { |
| authctxt->valid = 1; |
| debug2("%s: setting up authctxt for %s", |
| __func__, user); |
| } else { |
| /* Invalid user, fake password information */ |
| authctxt->pw = fakepw(); |
| #ifdef SSH_AUDIT_EVENTS |
| PRIVSEP(audit_event(SSH_INVALID_USER)); |
| #endif |
| } |
| #ifdef USE_PAM |
| if (options.use_pam) |
| PRIVSEP(start_pam(authctxt)); |
| #endif |
| ssh_packet_set_log_preamble(ssh, "%suser %s", |
| authctxt->valid ? "authenticating " : "invalid ", user); |
| setproctitle("%s%s", authctxt->valid ? user : "unknown", |
| use_privsep ? " [net]" : ""); |
| authctxt->service = xstrdup(service); |
| authctxt->style = style ? xstrdup(style) : NULL; |
| if (use_privsep) |
| mm_inform_authserv(service, style); |
| userauth_banner(); |
| if (auth2_setup_methods_lists(authctxt) != 0) |
| packet_disconnect("no authentication methods enabled"); |
| } else if (strcmp(user, authctxt->user) != 0 || |
| strcmp(service, authctxt->service) != 0) { |
| packet_disconnect("Change of username or service not allowed: " |
| "(%s,%s) -> (%s,%s)", |
| authctxt->user, authctxt->service, user, service); |
| } |
| /* reset state */ |
| auth2_challenge_stop(ssh); |
| |
| #ifdef GSSAPI |
| /* XXX move to auth2_gssapi_stop() */ |
| ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL); |
| ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL); |
| #endif |
| |
| auth2_authctxt_reset_info(authctxt); |
| authctxt->postponed = 0; |
| authctxt->server_caused_failure = 0; |
| |
| /* try to authenticate user */ |
| m = authmethod_lookup(authctxt, method); |
| if (m != NULL && authctxt->failures < options.max_authtries) { |
| debug2("input_userauth_request: try method %s", method); |
| authenticated = m->userauth(ssh); |
| } |
| if (!authctxt->authenticated) |
| ensure_minimum_time_since(tstart, |
| user_specific_delay(authctxt->user)); |
| userauth_finish(ssh, authenticated, method, NULL); |
| |
| free(service); |
| free(user); |
| free(method); |
| return 0; |
| } |
| |
| void |
| userauth_finish(struct ssh *ssh, int authenticated, const char *method, |
| const char *submethod) |
| { |
| Authctxt *authctxt = ssh->authctxt; |
| char *methods; |
| int partial = 0; |
| |
| if (!authctxt->valid && authenticated) |
| fatal("INTERNAL ERROR: authenticated invalid user %s", |
| authctxt->user); |
| if (authenticated && authctxt->postponed) |
| fatal("INTERNAL ERROR: authenticated and postponed"); |
| |
| /* Special handling for root */ |
| if (authenticated && authctxt->pw->pw_uid == 0 && |
| !auth_root_allowed(ssh, method)) { |
| authenticated = 0; |
| #ifdef SSH_AUDIT_EVENTS |
| PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED)); |
| #endif |
| } |
| |
| if (authenticated && options.num_auth_methods != 0) { |
| if (!auth2_update_methods_lists(authctxt, method, submethod)) { |
| authenticated = 0; |
| partial = 1; |
| } |
| } |
| |
| /* Log before sending the reply */ |
| auth_log(authctxt, authenticated, partial, method, submethod); |
| |
| /* Update information exposed to session */ |
| if (authenticated || partial) |
| auth2_update_session_info(authctxt, method, submethod); |
| |
| if (authctxt->postponed) |
| return; |
| |
| #ifdef USE_PAM |
| if (options.use_pam && authenticated) { |
| if (!PRIVSEP(do_pam_account())) { |
| /* if PAM returned a message, send it to the user */ |
| if (buffer_len(&loginmsg) > 0) { |
| buffer_append(&loginmsg, "\0", 1); |
| userauth_send_banner(buffer_ptr(&loginmsg)); |
| packet_write_wait(); |
| } |
| fatal("Access denied for user %s by PAM account " |
| "configuration", authctxt->user); |
| } |
| } |
| #endif |
| |
| if (authenticated == 1) { |
| /* turn off userauth */ |
| ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore); |
| packet_start(SSH2_MSG_USERAUTH_SUCCESS); |
| packet_send(); |
| packet_write_wait(); |
| /* now we can break out */ |
| authctxt->success = 1; |
| ssh_packet_set_log_preamble(ssh, "user %s", authctxt->user); |
| } else { |
| /* Allow initial try of "none" auth without failure penalty */ |
| if (!partial && !authctxt->server_caused_failure && |
| (authctxt->attempt > 1 || strcmp(method, "none") != 0)) |
| authctxt->failures++; |
| if (authctxt->failures >= options.max_authtries) { |
| #ifdef SSH_AUDIT_EVENTS |
| PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES)); |
| #endif |
| auth_maxtries_exceeded(authctxt); |
| } |
| methods = authmethods_get(authctxt); |
| debug3("%s: failure partial=%d next methods=\"%s\"", __func__, |
| partial, methods); |
| packet_start(SSH2_MSG_USERAUTH_FAILURE); |
| packet_put_cstring(methods); |
| packet_put_char(partial); |
| packet_send(); |
| packet_write_wait(); |
| free(methods); |
| } |
| } |
| |
| /* |
| * Checks whether method is allowed by at least one AuthenticationMethods |
| * methods list. Returns 1 if allowed, or no methods lists configured. |
| * 0 otherwise. |
| */ |
| int |
| auth2_method_allowed(Authctxt *authctxt, const char *method, |
| const char *submethod) |
| { |
| u_int i; |
| |
| /* |
| * NB. authctxt->num_auth_methods might be zero as a result of |
| * auth2_setup_methods_lists(), so check the configuration. |
| */ |
| if (options.num_auth_methods == 0) |
| return 1; |
| for (i = 0; i < authctxt->num_auth_methods; i++) { |
| if (list_starts_with(authctxt->auth_methods[i], method, |
| submethod) != MATCH_NONE) |
| return 1; |
| } |
| return 0; |
| } |
| |
| static char * |
| authmethods_get(Authctxt *authctxt) |
| { |
| struct sshbuf *b; |
| char *list; |
| int i, r; |
| |
| if ((b = sshbuf_new()) == NULL) |
| fatal("%s: sshbuf_new failed", __func__); |
| for (i = 0; authmethods[i] != NULL; i++) { |
| if (strcmp(authmethods[i]->name, "none") == 0) |
| continue; |
| if (authmethods[i]->enabled == NULL || |
| *(authmethods[i]->enabled) == 0) |
| continue; |
| if (!auth2_method_allowed(authctxt, authmethods[i]->name, |
| NULL)) |
| continue; |
| if ((r = sshbuf_putf(b, "%s%s", sshbuf_len(b) ? "," : "", |
| authmethods[i]->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; |
| } |
| |
| static Authmethod * |
| authmethod_lookup(Authctxt *authctxt, const char *name) |
| { |
| int i; |
| |
| if (name != NULL) |
| for (i = 0; authmethods[i] != NULL; i++) |
| if (authmethods[i]->enabled != NULL && |
| *(authmethods[i]->enabled) != 0 && |
| strcmp(name, authmethods[i]->name) == 0 && |
| auth2_method_allowed(authctxt, |
| authmethods[i]->name, NULL)) |
| return authmethods[i]; |
| debug2("Unrecognized authentication method name: %s", |
| name ? name : "NULL"); |
| return NULL; |
| } |
| |
| /* |
| * Check a comma-separated list of methods for validity. Is need_enable is |
| * non-zero, then also require that the methods are enabled. |
| * Returns 0 on success or -1 if the methods list is invalid. |
| */ |
| int |
| auth2_methods_valid(const char *_methods, int need_enable) |
| { |
| char *methods, *omethods, *method, *p; |
| u_int i, found; |
| int ret = -1; |
| |
| if (*_methods == '\0') { |
| error("empty authentication method list"); |
| return -1; |
| } |
| omethods = methods = xstrdup(_methods); |
| while ((method = strsep(&methods, ",")) != NULL) { |
| for (found = i = 0; !found && authmethods[i] != NULL; i++) { |
| if ((p = strchr(method, ':')) != NULL) |
| *p = '\0'; |
| if (strcmp(method, authmethods[i]->name) != 0) |
| continue; |
| if (need_enable) { |
| if (authmethods[i]->enabled == NULL || |
| *(authmethods[i]->enabled) == 0) { |
| error("Disabled method \"%s\" in " |
| "AuthenticationMethods list \"%s\"", |
| method, _methods); |
| goto out; |
| } |
| } |
| found = 1; |
| break; |
| } |
| if (!found) { |
| error("Unknown authentication method \"%s\" in list", |
| method); |
| goto out; |
| } |
| } |
| ret = 0; |
| out: |
| free(omethods); |
| return ret; |
| } |
| |
| /* |
| * Prune the AuthenticationMethods supplied in the configuration, removing |
| * any methods lists that include disabled methods. Note that this might |
| * leave authctxt->num_auth_methods == 0, even when multiple required auth |
| * has been requested. For this reason, all tests for whether multiple is |
| * enabled should consult options.num_auth_methods directly. |
| */ |
| int |
| auth2_setup_methods_lists(Authctxt *authctxt) |
| { |
| u_int i; |
| |
| if (options.num_auth_methods == 0) |
| return 0; |
| debug3("%s: checking methods", __func__); |
| authctxt->auth_methods = xcalloc(options.num_auth_methods, |
| sizeof(*authctxt->auth_methods)); |
| authctxt->num_auth_methods = 0; |
| for (i = 0; i < options.num_auth_methods; i++) { |
| if (auth2_methods_valid(options.auth_methods[i], 1) != 0) { |
| logit("Authentication methods list \"%s\" contains " |
| "disabled method, skipping", |
| options.auth_methods[i]); |
| continue; |
| } |
| debug("authentication methods list %d: %s", |
| authctxt->num_auth_methods, options.auth_methods[i]); |
| authctxt->auth_methods[authctxt->num_auth_methods++] = |
| xstrdup(options.auth_methods[i]); |
| } |
| if (authctxt->num_auth_methods == 0) { |
| error("No AuthenticationMethods left after eliminating " |
| "disabled methods"); |
| return -1; |
| } |
| return 0; |
| } |
| |
| static int |
| list_starts_with(const char *methods, const char *method, |
| const char *submethod) |
| { |
| size_t l = strlen(method); |
| int match; |
| const char *p; |
| |
| if (strncmp(methods, method, l) != 0) |
| return MATCH_NONE; |
| p = methods + l; |
| match = MATCH_METHOD; |
| if (*p == ':') { |
| if (!submethod) |
| return MATCH_PARTIAL; |
| l = strlen(submethod); |
| p += 1; |
| if (strncmp(submethod, p, l)) |
| return MATCH_NONE; |
| p += l; |
| match = MATCH_BOTH; |
| } |
| if (*p != ',' && *p != '\0') |
| return MATCH_NONE; |
| return match; |
| } |
| |
| /* |
| * Remove method from the start of a comma-separated list of methods. |
| * Returns 0 if the list of methods did not start with that method or 1 |
| * if it did. |
| */ |
| static int |
| remove_method(char **methods, const char *method, const char *submethod) |
| { |
| char *omethods = *methods, *p; |
| size_t l = strlen(method); |
| int match; |
| |
| match = list_starts_with(omethods, method, submethod); |
| if (match != MATCH_METHOD && match != MATCH_BOTH) |
| return 0; |
| p = omethods + l; |
| if (submethod && match == MATCH_BOTH) |
| p += 1 + strlen(submethod); /* include colon */ |
| if (*p == ',') |
| p++; |
| *methods = xstrdup(p); |
| free(omethods); |
| return 1; |
| } |
| |
| /* |
| * Called after successful authentication. Will remove the successful method |
| * from the start of each list in which it occurs. If it was the last method |
| * in any list, then authentication is deemed successful. |
| * Returns 1 if the method completed any authentication list or 0 otherwise. |
| */ |
| int |
| auth2_update_methods_lists(Authctxt *authctxt, const char *method, |
| const char *submethod) |
| { |
| u_int i, found = 0; |
| |
| debug3("%s: updating methods list after \"%s\"", __func__, method); |
| for (i = 0; i < authctxt->num_auth_methods; i++) { |
| if (!remove_method(&(authctxt->auth_methods[i]), method, |
| submethod)) |
| continue; |
| found = 1; |
| if (*authctxt->auth_methods[i] == '\0') { |
| debug2("authentication methods list %d complete", i); |
| return 1; |
| } |
| debug3("authentication methods list %d remaining: \"%s\"", |
| i, authctxt->auth_methods[i]); |
| } |
| /* This should not happen, but would be bad if it did */ |
| if (!found) |
| fatal("%s: method not in AuthenticationMethods", __func__); |
| return 0; |
| } |
| |
| /* Reset method-specific information */ |
| void auth2_authctxt_reset_info(Authctxt *authctxt) |
| { |
| sshkey_free(authctxt->auth_method_key); |
| free(authctxt->auth_method_info); |
| authctxt->auth_method_key = NULL; |
| authctxt->auth_method_info = NULL; |
| } |
| |
| /* Record auth method-specific information for logs */ |
| void |
| auth2_record_info(Authctxt *authctxt, const char *fmt, ...) |
| { |
| va_list ap; |
| int i; |
| |
| free(authctxt->auth_method_info); |
| authctxt->auth_method_info = NULL; |
| |
| va_start(ap, fmt); |
| i = vasprintf(&authctxt->auth_method_info, fmt, ap); |
| va_end(ap); |
| |
| if (i < 0 || authctxt->auth_method_info == NULL) |
| fatal("%s: vasprintf failed", __func__); |
| } |
| |
| /* |
| * Records a public key used in authentication. This is used for logging |
| * and to ensure that the same key is not subsequently accepted again for |
| * multiple authentication. |
| */ |
| void |
| auth2_record_key(Authctxt *authctxt, int authenticated, |
| const struct sshkey *key) |
| { |
| struct sshkey **tmp, *dup; |
| int r; |
| |
| if ((r = sshkey_demote(key, &dup)) != 0) |
| fatal("%s: copy key: %s", __func__, ssh_err(r)); |
| sshkey_free(authctxt->auth_method_key); |
| authctxt->auth_method_key = dup; |
| |
| if (!authenticated) |
| return; |
| |
| /* If authenticated, make sure we don't accept this key again */ |
| if ((r = sshkey_demote(key, &dup)) != 0) |
| fatal("%s: copy key: %s", __func__, ssh_err(r)); |
| if (authctxt->nprev_keys >= INT_MAX || |
| (tmp = recallocarray(authctxt->prev_keys, authctxt->nprev_keys, |
| authctxt->nprev_keys + 1, sizeof(*authctxt->prev_keys))) == NULL) |
| fatal("%s: reallocarray failed", __func__); |
| authctxt->prev_keys = tmp; |
| authctxt->prev_keys[authctxt->nprev_keys] = dup; |
| authctxt->nprev_keys++; |
| |
| } |
| |
| /* Checks whether a key has already been previously used for authentication */ |
| int |
| auth2_key_already_used(Authctxt *authctxt, const struct sshkey *key) |
| { |
| u_int i; |
| char *fp; |
| |
| for (i = 0; i < authctxt->nprev_keys; i++) { |
| if (sshkey_equal_public(key, authctxt->prev_keys[i])) { |
| fp = sshkey_fingerprint(authctxt->prev_keys[i], |
| options.fingerprint_hash, SSH_FP_DEFAULT); |
| debug3("%s: key already used: %s %s", __func__, |
| sshkey_type(authctxt->prev_keys[i]), |
| fp == NULL ? "UNKNOWN" : fp); |
| free(fp); |
| return 1; |
| } |
| } |
| return 0; |
| } |
| |
| /* |
| * Updates authctxt->session_info with details of authentication. Should be |
| * whenever an authentication method succeeds. |
| */ |
| void |
| auth2_update_session_info(Authctxt *authctxt, const char *method, |
| const char *submethod) |
| { |
| int r; |
| |
| if (authctxt->session_info == NULL) { |
| if ((authctxt->session_info = sshbuf_new()) == NULL) |
| fatal("%s: sshbuf_new", __func__); |
| } |
| |
| /* Append method[/submethod] */ |
| if ((r = sshbuf_putf(authctxt->session_info, "%s%s%s", |
| method, submethod == NULL ? "" : "/", |
| submethod == NULL ? "" : submethod)) != 0) |
| fatal("%s: append method: %s", __func__, ssh_err(r)); |
| |
| /* Append key if present */ |
| if (authctxt->auth_method_key != NULL) { |
| if ((r = sshbuf_put_u8(authctxt->session_info, ' ')) != 0 || |
| (r = sshkey_format_text(authctxt->auth_method_key, |
| authctxt->session_info)) != 0) |
| fatal("%s: append key: %s", __func__, ssh_err(r)); |
| } |
| |
| if (authctxt->auth_method_info != NULL) { |
| /* Ensure no ambiguity here */ |
| if (strchr(authctxt->auth_method_info, '\n') != NULL) |
| fatal("%s: auth_method_info contains \\n", __func__); |
| if ((r = sshbuf_put_u8(authctxt->session_info, ' ')) != 0 || |
| (r = sshbuf_putf(authctxt->session_info, "%s", |
| authctxt->auth_method_info)) != 0) { |
| fatal("%s: append method info: %s", |
| __func__, ssh_err(r)); |
| } |
| } |
| if ((r = sshbuf_put_u8(authctxt->session_info, '\n')) != 0) |
| fatal("%s: append: %s", __func__, ssh_err(r)); |
| } |
| |