X-Git-Url: http://andersk.mit.edu/gitweb/gssapi-openssh.git/blobdiff_plain/799ae497fc1f308e76517858d866bdd27b56cdd8..1325a69de3944e18b428a7343961a957cfe7c3dd:/openssh/auth2.c?ds=sidebyside diff --git a/openssh/auth2.c b/openssh/auth2.c index b1a4e36..1cd3e10 100644 --- a/openssh/auth2.c +++ b/openssh/auth2.c @@ -1,4 +1,4 @@ -/* $OpenBSD: auth2.c,v 1.114 2007/03/01 10:28:02 dtucker Exp $ */ +/* $OpenBSD: auth2.c,v 1.120 2008/11/04 08:22:12 djm Exp $ */ /* * Copyright (c) 2000 Markus Friedl. All rights reserved. * @@ -26,12 +26,17 @@ #include "includes.h" #include +#include +#include +#include #include #include #include +#include #include "xmalloc.h" +#include "atomicio.h" #include "ssh2.h" #include "packet.h" #include "log.h" @@ -44,6 +49,7 @@ #include "dispatch.h" #include "pathnames.h" #include "buffer.h" +#include "canohost.h" #ifdef GSSAPI #include "ssh-gss.h" @@ -64,14 +70,29 @@ extern Authmethod method_passwd; extern Authmethod method_kbdint; extern Authmethod method_hostbased; #ifdef GSSAPI +extern Authmethod method_external; +extern Authmethod method_gsskeyex; extern Authmethod method_gssapi; +extern Authmethod method_gssapi_compat; #endif +#ifdef JPAKE +extern Authmethod method_jpake; +#endif + +static int log_flag = 0; + Authmethod *authmethods[] = { &method_none, &method_pubkey, #ifdef GSSAPI + &method_gsskeyex, + &method_external, &method_gssapi, + &method_gssapi_compat, +#endif +#ifdef JPAKE + &method_jpake, #endif &method_passwd, &method_kbdint, @@ -87,12 +108,75 @@ static void input_userauth_request(int, u_int32_t, void *); /* helper */ static Authmethod *authmethod_lookup(const char *); static char *authmethods_get(void); -int user_key_allowed(struct passwd *, Key *); + +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 > 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) { + xfree(banner); + return (NULL); + } + banner[n] = '\0'; + + return (banner); +} + +void +userauth_send_banner(const char *msg) +{ + if (datafellows & SSH_BUG_BANNER) + return; + + 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 || + strcasecmp(options.banner, "none") == 0 || + (datafellows & SSH_BUG_BANNER) != 0) + return; + + if ((banner = PRIVSEP(auth2_read_banner())) == NULL) + goto done; + userauth_send_banner(banner); + +done: + if (banner) + xfree(banner); +} /* * loop until authctxt->success == TRUE */ - void do_authentication2(Authctxt *authctxt) { @@ -150,17 +234,65 @@ input_userauth_request(int type, u_int32_t seq, void *ctxt) user = packet_get_string(NULL); service = packet_get_string(NULL); method = packet_get_string(NULL); - debug("userauth-request for user %s service %s method %s", user, service, method); + +#ifdef GSSAPI + if (user[0] == '\0') { + debug("received empty username for %s", method); + if (strcmp(method, "external-keyx") == 0 || + strcmp(method, "gssapi-keyex") == 0) { + char *lname = NULL; + PRIVSEP(ssh_gssapi_localname(&lname)); + if (lname && lname[0] != '\0') { + xfree(user); + user = lname; + debug("set username to %s from gssapi context", user); + } else { + debug("failed to set username from gssapi context"); + packet_send_debug("failed to set username from gssapi context"); + } + } + } +#endif + + debug("userauth-request for user %s service %s method %s", + user[0] ? user : "", service, method); + if (!log_flag) { + logit("SSH: Server;Ltype: Authname;Remote: %s-%d;Name: %s", + get_remote_ipaddr(), get_remote_port(), + user[0] ? user : ""); + log_flag = 1; + } debug("attempt %d failures %d", authctxt->attempt, authctxt->failures); if ((style = strchr(user, ':')) != NULL) *style++ = 0; - if (authctxt->attempt++ == 0) { - /* setup auth context */ + /* If first time or username changed or empty username, + setup/reset authentication context. */ + if ((authctxt->attempt++ == 0) || + (strcmp(user, authctxt->user) != 0) || + (strcmp(user, "") == 0)) { + if (authctxt->user) { + xfree(authctxt->user); + authctxt->user = NULL; + } + authctxt->valid = 0; + authctxt->user = xstrdup(user); + if (strcmp(service, "ssh-connection") != 0) { + packet_disconnect("Unsupported service %s", service); + } +#ifdef GSSAPI + /* If we're going to set the username based on the + GSSAPI context later, then wait until then to + verify it. Just put in placeholders for now. */ + if ((strcmp(user, "") == 0) && + ((strcmp(method, "gssapi") == 0) || + (strcmp(method, "gssapi-with-mic") == 0))) { + authctxt->pw = fakepw(); + } else { +#endif authctxt->pw = PRIVSEP(getpwnamallow(user)); - authctxt->user = xstrdup(user); - if (authctxt->pw && strcmp(service, "ssh-connection")==0) { + if (authctxt->pw) { authctxt->valid = 1; debug2("input_userauth_request: setting up authctxt for %s", user); } else { @@ -170,35 +302,46 @@ input_userauth_request(int type, u_int32_t seq, void *ctxt) PRIVSEP(audit_event(SSH_INVALID_USER)); #endif } +#ifdef GSSAPI + } /* endif for setting username based on GSSAPI context */ +#endif #ifdef USE_PAM if (options.use_pam) PRIVSEP(start_pam(authctxt)); #endif 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); - } else if (strcmp(user, authctxt->user) != 0 || - strcmp(service, authctxt->service) != 0) { - packet_disconnect("Change of username or service not allowed: " + if (authctxt->attempt == 1) { + authctxt->service = xstrdup(service); + authctxt->style = style ? xstrdup(style) : NULL; + if (use_privsep) + mm_inform_authserv(service, style); + userauth_banner(); + } + } + if (strcmp(service, authctxt->service) != 0) { + packet_disconnect("Change of service not allowed: " "(%s,%s) -> (%s,%s)", authctxt->user, authctxt->service, user, service); } /* reset state */ auth2_challenge_stop(authctxt); +#ifdef JPAKE + auth2_jpake_stop(authctxt); +#endif #ifdef GSSAPI + /* XXX move to auth2_gssapi_stop() */ dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL); dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL); #endif authctxt->postponed = 0; + authctxt->server_caused_failure = 0; /* try to authenticate user */ m = authmethod_lookup(method); - if (m != NULL) { + if (m != NULL && authctxt->failures < options.max_authtries) { debug2("input_userauth_request: try method %s", method); authenticated = m->userauth(authctxt); } @@ -265,7 +408,12 @@ userauth_finish(Authctxt *authctxt, int authenticated, char *method) /* now we can break out */ authctxt->success = 1; } else { - if (authctxt->failures++ > options.max_authtries) { + /* Dont count server configuration issues against the client */ + /* Allow initial try of "none" auth without failure penalty */ + if (!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 @@ -281,8 +429,6 @@ userauth_finish(Authctxt *authctxt, int authenticated, char *method) } } -#define DELIM "," - static char * authmethods_get(void) { @@ -323,3 +469,4 @@ authmethod_lookup(const char *name) name ? name : "NULL"); return NULL; } +