X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/6ae2364d36eaebbbc830a417d5a01ebf3cc84e5f..3ca6cc4502cb4bd35b092cfde50b0ed51ddde7a9:/auth.c diff --git a/auth.c b/auth.c index 4c6f32b0..1f976eee 100644 --- a/auth.c +++ b/auth.c @@ -1,77 +1,114 @@ /* - * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland - * All rights reserved - * Copyright (c) 2000 Markus Friedl. All rights reserved. + * 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("$OpenBSD: auth.c,v 1.4 2000/04/14 10:30:29 markus Exp $"); +RCSID("$OpenBSD: auth.c,v 1.21 2001/03/19 17:07:23 markus Exp $"); + +#ifdef HAVE_LOGIN_H +#include +#endif +#if defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW) +#include +#endif /* defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW) */ #include "xmalloc.h" -#include "rsa.h" -#include "ssh.h" -#include "pty.h" -#include "packet.h" -#include "buffer.h" -#include "cipher.h" -#include "mpaux.h" -#include "servconf.h" -#include "compat.h" -#include "channels.h" #include "match.h" - -#include "bufaux.h" -#include "ssh2.h" +#include "groupaccess.h" +#include "log.h" +#include "servconf.h" #include "auth.h" -#include "session.h" -#include "dispatch.h" - +#include "auth-options.h" +#include "canohost.h" /* import */ extern ServerOptions options; -extern char *forced_command; /* - * Check if the user is allowed to log in via ssh. If user is listed in - * DenyUsers or user's primary group is listed in DenyGroups, false will - * be returned. If AllowUsers isn't empty and user isn't listed there, or - * if AllowGroups isn't empty and user isn't listed there, false will be - * returned. + * Check if the user is allowed to log in via ssh. If user is listed + * in DenyUsers or one of user's groups is listed in DenyGroups, false + * will be returned. If AllowUsers isn't empty and user isn't listed + * there, or if AllowGroups isn't empty and one of user's groups isn't + * listed there, false will be returned. * If the user's shell is not executable, false will be returned. * Otherwise true is returned. */ -static int +int allowed_user(struct passwd * pw) { struct stat st; - struct group *grp; + char *shell; int i; #ifdef WITH_AIXAUTHENTICATE char *loginmsg; #endif /* WITH_AIXAUTHENTICATE */ +#if !defined(USE_PAM) && defined(HAVE_SHADOW_H) && \ + !defined(DISABLE_SHADOW) && defined(HAS_SHADOW_EXPIRE) + struct spwd *spw; + + /* Shouldn't be called if pw is NULL, but better safe than sorry... */ + if (!pw || !pw->pw_name) + return 0; + + spw = getspnam(pw->pw_name); + if (spw != NULL) { + int days = time(NULL) / 86400; + + /* Check account expiry */ + if ((spw->sp_expire >= 0) && (days > spw->sp_expire)) + return 0; + /* Check password expiry */ + if ((spw->sp_lstchg >= 0) && (spw->sp_max >= 0) && + (days > (spw->sp_lstchg + spw->sp_max))) + return 0; + } +#else /* Shouldn't be called if pw is NULL, but better safe than sorry... */ - if (!pw) + if (!pw || !pw->pw_name) return 0; +#endif + + /* + * Get the shell from the password data. An empty shell field is + * legal, and means /bin/sh. + */ + shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell; /* deny if shell does not exists or is not executable */ - if (stat(pw->pw_shell, &st) != 0) + if (stat(shell, &st) != 0) return 0; if (!((st.st_mode & S_IFREG) && (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)))) return 0; /* Return false if user is listed in DenyUsers */ if (options.num_deny_users > 0) { - if (!pw->pw_name) - return 0; for (i = 0; i < options.num_deny_users; i++) if (match_pattern(pw->pw_name, options.deny_users[i])) return 0; } /* Return false if AllowUsers isn't empty and user isn't listed there */ if (options.num_allow_users > 0) { - if (!pw->pw_name) - return 0; for (i = 0; i < options.num_allow_users; i++) if (match_pattern(pw->pw_name, options.allow_users[i])) break; @@ -79,724 +116,109 @@ allowed_user(struct passwd * pw) if (i >= options.num_allow_users) return 0; } - /* Get the primary group name if we need it. Return false if it fails */ if (options.num_deny_groups > 0 || options.num_allow_groups > 0) { - grp = getgrgid(pw->pw_gid); - if (!grp) + /* Get the user's group access list (primary and supplementary) */ + if (ga_init(pw->pw_name, pw->pw_gid) == 0) return 0; - /* Return false if user's group is listed in DenyGroups */ - if (options.num_deny_groups > 0) { - if (!grp->gr_name) + /* Return false if one of user's groups is listed in DenyGroups */ + if (options.num_deny_groups > 0) + if (ga_match(options.deny_groups, + options.num_deny_groups)) { + ga_free(); return 0; - for (i = 0; i < options.num_deny_groups; i++) - if (match_pattern(grp->gr_name, options.deny_groups[i])) - return 0; - } + } /* - * Return false if AllowGroups isn't empty and user's group + * Return false if AllowGroups isn't empty and one of user's groups * isn't listed there */ - if (options.num_allow_groups > 0) { - if (!grp->gr_name) - return 0; - for (i = 0; i < options.num_allow_groups; i++) - if (match_pattern(grp->gr_name, options.allow_groups[i])) - break; - /* i < options.num_allow_groups iff we break for - loop */ - if (i >= options.num_allow_groups) + if (options.num_allow_groups > 0) + if (!ga_match(options.allow_groups, + options.num_allow_groups)) { + ga_free(); return 0; - } + } + ga_free(); } #ifdef WITH_AIXAUTHENTICATE - if (loginrestrictions(pw->pw_name,S_LOGIN,NULL,&loginmsg) != 0) + if (loginrestrictions(pw->pw_name, S_RLOGIN, NULL, &loginmsg) != 0) { + if (loginmsg && *loginmsg) { + /* Remove embedded newlines (if any) */ + char *p; + for (p = loginmsg; *p; p++) { + if (*p == '\n') + *p = ' '; + } + /* Remove trailing newline */ + *--p = '\0'; + log("Login restricted for %s: %.100s", pw->pw_name, loginmsg); + } return 0; + } #endif /* WITH_AIXAUTHENTICATE */ /* We found no reason not to let this user try to log on... */ return 1; } -/* - * convert ssh auth msg type into description - */ -char * -get_authname(int type) +Authctxt * +authctxt_new(void) { - static char buf[1024]; - switch (type) { - case SSH_CMSG_AUTH_PASSWORD: - return "password"; - case SSH_CMSG_AUTH_RSA: - return "rsa"; - case SSH_CMSG_AUTH_RHOSTS_RSA: - return "rhosts-rsa"; - case SSH_CMSG_AUTH_RHOSTS: - return "rhosts"; -#ifdef KRB4 - case SSH_CMSG_AUTH_KERBEROS: - return "kerberos"; -#endif -#ifdef SKEY - case SSH_CMSG_AUTH_TIS_RESPONSE: - return "s/key"; -#endif - } - snprintf(buf, sizeof buf, "bad-auth-msg-%d", type); - return buf; + Authctxt *authctxt = xmalloc(sizeof(*authctxt)); + memset(authctxt, 0, sizeof(*authctxt)); + return authctxt; } -#define AUTH_FAIL_MAX 6 -#define AUTH_FAIL_LOG (AUTH_FAIL_MAX/2) -#define AUTH_FAIL_MSG "Too many authentication failures for %.100s" - -/* - * The user does not exist or access is denied, - * but fake indication that authentication is needed. - */ void -do_fake_authloop1(char *user) +auth_log(Authctxt *authctxt, int authenticated, char *method, char *info) { - int attempt = 0; - - log("Faking authloop for illegal user %.200s from %.200s port %d", - user, - get_remote_ipaddr(), - get_remote_port()); - -#ifdef WITH_AIXAUTHENTICATE - if (strncmp(get_authname(type),"password", - strlen(get_authname(type))) == 0) - loginfailed(pw->pw_name,get_canonical_hostname(),"ssh"); -#endif /* WITH_AIXAUTHENTICATE */ - - /* Indicate that authentication is needed. */ - packet_start(SSH_SMSG_FAILURE); - packet_send(); - packet_write_wait(); - - /* - * Keep reading packets, and always respond with a failure. This is - * to avoid disclosing whether such a user really exists. - */ - for (attempt = 1;; attempt++) { - /* Read a packet. This will not return if the client disconnects. */ - int plen; -#ifndef SKEY - (void)packet_read(&plen); -#else /* SKEY */ - int type = packet_read(&plen); - unsigned int dlen; - char *password, *skeyinfo; - /* Try to send a fake s/key challenge. */ - if (options.skey_authentication == 1 && - (skeyinfo = skey_fake_keyinfo(user)) != NULL) { - password = NULL; - if (type == SSH_CMSG_AUTH_TIS) { - packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE); - packet_put_string(skeyinfo, strlen(skeyinfo)); - packet_send(); - packet_write_wait(); - continue; - } else if (type == SSH_CMSG_AUTH_PASSWORD && - options.password_authentication && - (password = packet_get_string(&dlen)) != NULL && - dlen == 5 && - strncasecmp(password, "s/key", 5) == 0 ) { - packet_send_debug(skeyinfo); - } - if (password != NULL) - xfree(password); - } -#endif - if (attempt > AUTH_FAIL_MAX) - packet_disconnect(AUTH_FAIL_MSG, user); - - /* - * Send failure. This should be indistinguishable from a - * failed authentication. - */ - packet_start(SSH_SMSG_FAILURE); - packet_send(); - packet_write_wait(); - } - /* NOTREACHED */ - abort(); -} - -/* - * read packets and try to authenticate local user *pw. - * return if authentication is successfull - */ -void -do_authloop(struct passwd * pw) -{ - int attempt = 0; - unsigned int bits; - RSA *client_host_key; - BIGNUM *n; - char *client_user = NULL, *password = NULL; - char user[1024]; - unsigned int dlen; - int plen, nlen, elen; - unsigned int ulen; - int type = 0; void (*authlog) (const char *fmt,...) = verbose; - - /* Indicate that authentication is needed. */ - packet_start(SSH_SMSG_FAILURE); - packet_send(); - packet_write_wait(); - - for (attempt = 1;; attempt++) { - int authenticated = 0; - strlcpy(user, "", sizeof user); - - /* Get a packet from the client. */ - type = packet_read(&plen); - - /* Process the packet. */ - switch (type) { -#ifdef AFS - case SSH_CMSG_HAVE_KERBEROS_TGT: - if (!options.kerberos_tgt_passing) { - /* packet_get_all(); */ - verbose("Kerberos tgt passing disabled."); - break; - } else { - /* Accept Kerberos tgt. */ - char *tgt = packet_get_string(&dlen); - packet_integrity_check(plen, 4 + dlen, type); - if (!auth_kerberos_tgt(pw, tgt)) - verbose("Kerberos tgt REFUSED for %s", pw->pw_name); - xfree(tgt); - } - continue; - - case SSH_CMSG_HAVE_AFS_TOKEN: - if (!options.afs_token_passing || !k_hasafs()) { - /* packet_get_all(); */ - verbose("AFS token passing disabled."); - break; - } else { - /* Accept AFS token. */ - char *token_string = packet_get_string(&dlen); - packet_integrity_check(plen, 4 + dlen, type); - if (!auth_afs_token(pw, token_string)) - verbose("AFS token REFUSED for %s", pw->pw_name); - xfree(token_string); - } - continue; -#endif /* AFS */ -#ifdef KRB4 - case SSH_CMSG_AUTH_KERBEROS: - if (!options.kerberos_authentication) { - /* packet_get_all(); */ - verbose("Kerberos authentication disabled."); - break; - } else { - /* Try Kerberos v4 authentication. */ - KTEXT_ST auth; - char *tkt_user = NULL; - char *kdata = packet_get_string((unsigned int *) &auth.length); - packet_integrity_check(plen, 4 + auth.length, type); - - if (auth.length < MAX_KTXT_LEN) - memcpy(auth.dat, kdata, auth.length); - xfree(kdata); - - authenticated = auth_krb4(pw->pw_name, &auth, &tkt_user); - - if (authenticated) { - snprintf(user, sizeof user, " tktuser %s", tkt_user); - xfree(tkt_user); - } - } - break; -#endif /* KRB4 */ - - case SSH_CMSG_AUTH_RHOSTS: - if (!options.rhosts_authentication) { - verbose("Rhosts authentication disabled."); - break; - } - /* - * Get client user name. Note that we just have to - * trust the client; this is one reason why rhosts - * authentication is insecure. (Another is - * IP-spoofing on a local network.) - */ - client_user = packet_get_string(&ulen); - packet_integrity_check(plen, 4 + ulen, type); - - /* Try to authenticate using /etc/hosts.equiv and - .rhosts. */ - authenticated = auth_rhosts(pw, client_user); - - snprintf(user, sizeof user, " ruser %s", client_user); - break; - - case SSH_CMSG_AUTH_RHOSTS_RSA: - if (!options.rhosts_rsa_authentication) { - verbose("Rhosts with RSA authentication disabled."); - break; - } - /* - * Get client user name. Note that we just have to - * trust the client; root on the client machine can - * claim to be any user. - */ - client_user = packet_get_string(&ulen); - - /* Get the client host key. */ - client_host_key = RSA_new(); - if (client_host_key == NULL) - fatal("RSA_new failed"); - client_host_key->e = BN_new(); - client_host_key->n = BN_new(); - if (client_host_key->e == NULL || client_host_key->n == NULL) - fatal("BN_new failed"); - bits = packet_get_int(); - packet_get_bignum(client_host_key->e, &elen); - packet_get_bignum(client_host_key->n, &nlen); - - if (bits != BN_num_bits(client_host_key->n)) - error("Warning: keysize mismatch for client_host_key: " - "actual %d, announced %d", BN_num_bits(client_host_key->n), bits); - packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type); - - authenticated = auth_rhosts_rsa(pw, client_user, client_host_key); - RSA_free(client_host_key); - - snprintf(user, sizeof user, " ruser %s", client_user); - break; - - case SSH_CMSG_AUTH_RSA: - if (!options.rsa_authentication) { - verbose("RSA authentication disabled."); - break; - } - /* RSA authentication requested. */ - n = BN_new(); - packet_get_bignum(n, &nlen); - packet_integrity_check(plen, nlen, type); - authenticated = auth_rsa(pw, n); - BN_clear_free(n); - break; - - case SSH_CMSG_AUTH_PASSWORD: - if (!options.password_authentication) { - verbose("Password authentication disabled."); - break; - } - /* - * Read user password. It is in plain text, but was - * transmitted over the encrypted channel so it is - * not visible to an outside observer. - */ - password = packet_get_string(&dlen); - packet_integrity_check(plen, 4 + dlen, type); - -#ifdef USE_PAM - /* Do PAM auth with password */ - authenticated = auth_pam_password(pw, password); -#else /* USE_PAM */ - /* Try authentication with the password. */ - authenticated = auth_password(pw, password); -#endif /* USE_PAM */ - memset(password, 0, strlen(password)); - xfree(password); - break; - -#ifdef SKEY - case SSH_CMSG_AUTH_TIS: - debug("rcvd SSH_CMSG_AUTH_TIS"); - if (options.skey_authentication == 1) { - char *skeyinfo = skey_keyinfo(pw->pw_name); - if (skeyinfo == NULL) { - debug("generating fake skeyinfo for %.100s.", pw->pw_name); - skeyinfo = skey_fake_keyinfo(pw->pw_name); - } - if (skeyinfo != NULL) { - /* we send our s/key- in tis-challenge messages */ - debug("sending challenge '%s'", skeyinfo); - packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE); - packet_put_string(skeyinfo, strlen(skeyinfo)); - packet_send(); - packet_write_wait(); - continue; - } - } - break; - case SSH_CMSG_AUTH_TIS_RESPONSE: - debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE"); - if (options.skey_authentication == 1) { - char *response = packet_get_string(&dlen); - debug("skey response == '%s'", response); - packet_integrity_check(plen, 4 + dlen, type); - authenticated = (skey_haskey(pw->pw_name) == 0 && - skey_passcheck(pw->pw_name, response) != -1); - xfree(response); - } - break; -#else - case SSH_CMSG_AUTH_TIS: - /* TIS Authentication is unsupported */ - log("TIS authentication unsupported."); - break; -#endif - - default: - /* - * Any unknown messages will be ignored (and failure - * returned) during authentication. - */ - log("Unknown message during authentication: type %d", type); - break; - } - - /* - * Check if the user is logging in as root and root logins - * are disallowed. - * Note that root login is allowed for forced commands. - */ - if (authenticated && pw->pw_uid == 0 && !options.permit_root_login) { - if (forced_command) { - log("Root login accepted for forced command."); - } else { - authenticated = 0; - log("ROOT LOGIN REFUSED FROM %.200s", - get_canonical_hostname()); - } - } - - /* Raise logging level */ - if (authenticated || - attempt == AUTH_FAIL_LOG || - type == SSH_CMSG_AUTH_PASSWORD) - authlog = log; - - authlog("%s %s for %.200s from %.200s port %d%s", - authenticated ? "Accepted" : "Failed", - get_authname(type), - pw->pw_uid == 0 ? "ROOT" : pw->pw_name, - get_remote_ipaddr(), - get_remote_port(), - user); - -#ifdef USE_PAM - if (authenticated) { - if (!do_pam_account(pw->pw_name, client_user)) { - if (client_user != NULL) { - xfree(client_user); - client_user = NULL; - } - do_fake_authloop1(pw->pw_name); - } - return; - } -#else /* USE_PAM */ - if (authenticated) { - return; - } -#endif /* USE_PAM */ - - if (client_user != NULL) { - xfree(client_user); - client_user = NULL; - } - - if (attempt > AUTH_FAIL_MAX) - packet_disconnect(AUTH_FAIL_MSG, pw->pw_name); - - /* Send a message indicating that the authentication attempt failed. */ - packet_start(SSH_SMSG_FAILURE); - packet_send(); - packet_write_wait(); - } + char *authmsg; + + /* Raise logging level */ + if (authenticated == 1 || + !authctxt->valid || + authctxt->failures >= AUTH_FAIL_LOG || + strcmp(method, "password") == 0) + authlog = log; + + if (authctxt->postponed) + authmsg = "Postponed"; + else + authmsg = authenticated ? "Accepted" : "Failed"; + + authlog("%s %s for %s%.100s from %.200s port %d%s", + authmsg, + method, + authctxt->valid ? "" : "illegal user ", + authctxt->valid && authctxt->pw->pw_uid == 0 ? "ROOT" : authctxt->user, + get_remote_ipaddr(), + get_remote_port(), + info); } /* - * Performs authentication of an incoming connection. Session key has already - * been exchanged and encryption is enabled. + * Check whether root logins are disallowed. */ -void -do_authentication() -{ - struct passwd *pw, pwcopy; - int plen; - unsigned int ulen; - char *user; -#ifdef WITH_AIXAUTHENTICATE - char *loginmsg; -#endif /* WITH_AIXAUTHENTICATE */ - - /* Get the name of the user that we wish to log in as. */ - packet_read_expect(&plen, SSH_CMSG_USER); - - /* Get the user name. */ - user = packet_get_string(&ulen); - packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER); - - setproctitle("%s", user); - -#ifdef AFS - /* If machine has AFS, set process authentication group. */ - if (k_hasafs()) { - k_setpag(); - k_unlog(); - } -#endif /* AFS */ - - /* Verify that the user is a valid user. */ - pw = getpwnam(user); - if (!pw || !allowed_user(pw)) - do_fake_authloop1(user); - xfree(user); - - /* Take a copy of the returned structure. */ - memset(&pwcopy, 0, sizeof(pwcopy)); - pwcopy.pw_name = xstrdup(pw->pw_name); - pwcopy.pw_passwd = xstrdup(pw->pw_passwd); - pwcopy.pw_uid = pw->pw_uid; - pwcopy.pw_gid = pw->pw_gid; - pwcopy.pw_dir = xstrdup(pw->pw_dir); - pwcopy.pw_shell = xstrdup(pw->pw_shell); - pw = &pwcopy; - -#ifdef USE_PAM - start_pam(pw); -#endif - - /* - * If we are not running as root, the user must have the same uid as - * the server. - */ - if (getuid() != 0 && pw->pw_uid != getuid()) - packet_disconnect("Cannot change user when server not running as root."); - - debug("Attempting authentication for %.100s.", pw->pw_name); - - /* If the user has no password, accept authentication immediately. */ - if (options.password_authentication && -#ifdef KRB4 - (!options.kerberos_authentication || options.kerberos_or_local_passwd) && -#endif /* KRB4 */ -#ifdef USE_PAM - auth_pam_password(pw, "")) { -#else /* USE_PAM */ - auth_password(pw, "")) { -#endif /* USE_PAM */ - /* Authentication with empty password succeeded. */ - log("Login for user %s from %.100s, accepted without authentication.", - pw->pw_name, get_remote_ipaddr()); - } else { - /* Loop until the user has been authenticated or the - connection is closed, do_authloop() returns only if - authentication is successfull */ - do_authloop(pw); - } - - /* The user has been authenticated and accepted. */ -#ifdef WITH_AIXAUTHENTICATE - loginsuccess(user,get_canonical_hostname(),"ssh",&loginmsg); -#endif /* WITH_AIXAUTHENTICATE */ - packet_start(SSH_SMSG_SUCCESS); - packet_send(); - packet_write_wait(); - - /* Perform session preparation. */ - do_authenticated(pw); -} - - -void input_service_request(int type, int plen); -void input_userauth_request(int type, int plen); -void ssh2_pty_cleanup(void); - -typedef struct Authctxt Authctxt; -struct Authctxt { - char *user; - char *service; - struct passwd pw; - int valid; -}; -static Authctxt *authctxt = NULL; -static int userauth_success = 0; - -struct passwd* -auth_get_user(void) +int +auth_root_allowed(char *method) { - return (authctxt != NULL && authctxt->valid) ? &authctxt->pw : NULL; -} -struct passwd* -auth_set_user(char *u, char *s) -{ - struct passwd *pw, *copy; - - if (authctxt == NULL) { - authctxt = xmalloc(sizeof(*authctxt)); - authctxt->valid = 0; - authctxt->user = xstrdup(u); - authctxt->service = xstrdup(s); - setproctitle("%s", u); - pw = getpwnam(u); - if (!pw || !allowed_user(pw)) { - log("auth_set_user: bad user %s", u); - return NULL; - } -#ifdef USE_PAM - start_pam(pw); -#endif - copy = &authctxt->pw; - memset(copy, 0, sizeof(*copy)); - copy->pw_name = xstrdup(pw->pw_name); - copy->pw_passwd = xstrdup(pw->pw_passwd); - copy->pw_uid = pw->pw_uid; - copy->pw_gid = pw->pw_gid; - copy->pw_dir = xstrdup(pw->pw_dir); - copy->pw_shell = xstrdup(pw->pw_shell); - authctxt->valid = 1; - } else { - if (strcmp(u, authctxt->user) != 0 || - strcmp(s, authctxt->service) != 0) { - log("auth_set_user: missmatch: (%s,%s)!=(%s,%s)", - u, s, authctxt->user, authctxt->service); - return NULL; + switch (options.permit_root_login) { + case PERMIT_YES: + return 1; + break; + case PERMIT_NO_PASSWD: + if (strcmp(method, "password") != 0) + return 1; + break; + case PERMIT_FORCED_ONLY: + if (forced_command) { + log("Root login accepted for forced command."); + return 1; } + break; } - return auth_get_user(); -} - -static void -protocol_error(int type, int plen) -{ - log("auth: protocol error: type %d plen %d", type, plen); - packet_start(SSH2_MSG_UNIMPLEMENTED); - packet_put_int(0); - packet_send(); - packet_write_wait(); -} -void -input_service_request(int type, int plen) -{ - unsigned int len; - int accept = 0; - char *service = packet_get_string(&len); - packet_done(); - - if (strcmp(service, "ssh-userauth") == 0) { - if (!userauth_success) { - accept = 1; - /* now we can handle user-auth requests */ - dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request); - } - } - /* XXX all other service requests are denied */ - - if (accept) { - 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); - } - xfree(service); -} -void -input_userauth_request(int type, int plen) -{ - static int try = 0; - unsigned int len; - int c, authenticated = 0; - char *user, *service, *method; - struct passwd *pw; - - if (++try == AUTH_FAIL_MAX) - packet_disconnect("too many failed userauth_requests"); - - user = packet_get_string(&len); - service = packet_get_string(&len); - method = packet_get_string(&len); - debug("userauth-request for user %s service %s method %s", user, service, method); - - /* XXX we only allow the ssh-connection service */ - pw = auth_set_user(user, service); - if (pw && strcmp(service, "ssh-connection")==0) { - if (strcmp(method, "none") == 0 && try == 1) { - packet_done(); -#ifdef USE_PAM - /* Do PAM auth with password */ - authenticated = auth_pam_password(pw, ""); -#else /* USE_PAM */ - /* Try authentication with the password. */ - authenticated = auth_password(pw, ""); -#endif /* USE_PAM */ - } else if (strcmp(method, "password") == 0) { - char *password; - c = packet_get_char(); - if (c) - debug("password change not supported"); - password = packet_get_string(&len); - packet_done(); -#ifdef USE_PAM - /* Do PAM auth with password */ - authenticated = auth_pam_password(pw, password); -#else /* USE_PAM */ - /* Try authentication with the password. */ - authenticated = auth_password(pw, password); -#endif /* USE_PAM */ - memset(password, 0, len); - xfree(password); - } else if (strcmp(method, "publickey") == 0) { - /* XXX TODO */ - char *pkalg, *pkblob, *sig; - int have_sig = packet_get_char(); - pkalg = packet_get_string(&len); - pkblob = packet_get_string(&len); - if (have_sig) { - sig = packet_get_string(&len); - /* test for correct signature */ - packet_done(); - xfree(sig); - } else { - packet_done(); - /* test whether pkalg/pkblob are acceptable */ - } - xfree(pkalg); - xfree(pkblob); - } - } - /* XXX check if other auth methods are needed */ - if (authenticated) { - /* turn off userauth */ - dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &protocol_error); - packet_start(SSH2_MSG_USERAUTH_SUCCESS); - packet_send(); - packet_write_wait(); - log("userauth success for %s", user); - /* now we can break out */ - userauth_success = 1; - } else { - packet_start(SSH2_MSG_USERAUTH_FAILURE); - packet_put_cstring("password"); - packet_put_char(0); /* partial success */ - packet_send(); - packet_write_wait(); - } - xfree(service); - xfree(user); - xfree(method); -} -void -do_authentication2() -{ - dispatch_init(&protocol_error); - dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request); - dispatch_run(DISPATCH_BLOCK, &userauth_success); - do_authenticated2(); + log("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr()); + return 0; }