X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/c345cf9d1095299a9077386c1188a86090d385a9..24ca682167d6d1f013d2733d96497cc545ce08f7:/auth-krb4.c diff --git a/auth-krb4.c b/auth-krb4.c index ae2b2a3d..f7a144f9 100644 --- a/auth-krb4.c +++ b/auth-krb4.c @@ -1,59 +1,130 @@ /* - * Dug Song - * Kerberos v4 authentication and ticket-passing routines. + * Copyright (c) 1999 Dug Song. 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-krb4.c,v 1.25 2001/12/19 07:18:56 deraadt Exp $"); + +#include "ssh.h" +#include "ssh1.h" #include "packet.h" #include "xmalloc.h" -#include "ssh.h" +#include "log.h" #include "servconf.h" +#include "uidswap.h" +#include "auth.h" -RCSID("$OpenBSD: auth-krb4.c,v 1.16 2000/08/02 17:27:04 provos Exp $"); +#ifdef AFS +#include "radix.h" +#endif #ifdef KRB4 -char *ticket = NULL; - extern ServerOptions options; +static int +krb4_init(void *context) +{ + static int cleanup_registered = 0; + Authctxt *authctxt = (Authctxt *)context; + const char *tkt_root = TKT_ROOT; + struct stat st; + int fd; + + if (!authctxt->krb4_ticket_file) { + /* Set unique ticket string manually since we're still root. */ + authctxt->krb4_ticket_file = xmalloc(MAXPATHLEN); +#ifdef AFS + if (lstat("/ticket", &st) != -1) + tkt_root = "/ticket/"; +#endif /* AFS */ + snprintf(authctxt->krb4_ticket_file, MAXPATHLEN, "%s%u_%d", + tkt_root, authctxt->pw->pw_uid, getpid()); + krb_set_tkt_string(authctxt->krb4_ticket_file); + } + /* Register ticket cleanup in case of fatal error. */ + if (!cleanup_registered) { + fatal_add_cleanup(krb4_cleanup_proc, authctxt); + cleanup_registered = 1; + } + /* Try to create our ticket file. */ + if ((fd = mkstemp(authctxt->krb4_ticket_file)) != -1) { + close(fd); + return (1); + } + /* Ticket file exists - make sure user owns it (just passed ticket). */ + if (lstat(authctxt->krb4_ticket_file, &st) != -1) { + if (st.st_mode == (S_IFREG | S_IRUSR | S_IWUSR) && + st.st_uid == authctxt->pw->pw_uid) + return (1); + } + /* Failure - cancel cleanup function, leaving ticket for inspection. */ + log("WARNING: bad ticket file %s", authctxt->krb4_ticket_file); + + fatal_remove_cleanup(krb4_cleanup_proc, authctxt); + cleanup_registered = 0; + + xfree(authctxt->krb4_ticket_file); + authctxt->krb4_ticket_file = NULL; + + return (0); +} + /* * try krb4 authentication, * return 1 on success, 0 on failure, -1 if krb4 is not available */ - int -auth_krb4_password(struct passwd * pw, const char *password) +auth_krb4_password(Authctxt *authctxt, const char *password) { AUTH_DAT adata; KTEXT_ST tkt; struct hostent *hp; - unsigned long faddr; - char localhost[MAXHOSTNAMELEN]; - char phost[INST_SZ]; - char realm[REALM_SZ]; + struct passwd *pw; + char localhost[MAXHOSTNAMELEN], phost[INST_SZ], realm[REALM_SZ]; + u_int32_t faddr; int r; + if ((pw = authctxt->pw) == NULL) + return (0); + /* * Try Kerberos password authentication only for non-root * users and only if Kerberos is installed. */ if (pw->pw_uid != 0 && krb_get_lrealm(realm, 1) == KSUCCESS) { - /* Set up our ticket file. */ - if (!krb4_init(pw->pw_uid)) { + if (!krb4_init(authctxt)) { log("Couldn't initialize Kerberos ticket file for %s!", pw->pw_name); - goto kerberos_auth_failure; + goto failure; } /* Try to get TGT using our password. */ - r = krb_get_pw_in_tkt((char *) pw->pw_name, "", - realm, "krbtgt", realm, - DEFAULT_TKT_LIFE, (char *) password); + r = krb_get_pw_in_tkt((char *) pw->pw_name, "", realm, + "krbtgt", realm, DEFAULT_TKT_LIFE, (char *)password); if (r != INTK_OK) { - packet_send_debug("Kerberos V4 password " - "authentication for %s failed: %s", - pw->pw_name, krb_err_txt[r]); - goto kerberos_auth_failure; + debug("Kerberos v4 password authentication for %s " + "failed: %s", pw->pw_name, krb_err_txt[r]); + goto failure; } /* Successful authentication. */ chown(tkt_string(), pw->pw_uid, pw->pw_gid); @@ -63,17 +134,17 @@ auth_krb4_password(struct passwd * pw, const char *password) * "rcmd" ticket to ensure that we are not talking * to a bogus Kerberos server. */ - (void) gethostname(localhost, sizeof(localhost)); - (void) strlcpy(phost, (char *) krb_get_phost(localhost), - INST_SZ); + gethostname(localhost, sizeof(localhost)); + strlcpy(phost, (char *)krb_get_phost(localhost), + sizeof(phost)); r = krb_mk_req(&tkt, KRB4_SERVICE_NAME, phost, realm, 33); if (r == KSUCCESS) { - if (!(hp = gethostbyname(localhost))) { + if ((hp = gethostbyname(localhost)) == NULL) { log("Couldn't get local host address!"); - goto kerberos_auth_failure; + goto failure; } - memmove((void *) &faddr, (void *) hp->h_addr, + memmove((void *)&faddr, (void *)hp->h_addr, sizeof(faddr)); /* Verify our "rcmd" ticket. */ @@ -84,116 +155,71 @@ auth_krb4_password(struct passwd * pw, const char *password) * Probably didn't have a srvtab on * localhost. Disallow login. */ - log("Kerberos V4 TGT for %s unverifiable, " + log("Kerberos v4 TGT for %s unverifiable, " "no srvtab installed? krb_rd_req: %s", pw->pw_name, krb_err_txt[r]); - goto kerberos_auth_failure; + goto failure; } else if (r != KSUCCESS) { - log("Kerberos V4 %s ticket unverifiable: %s", + log("Kerberos v4 %s ticket unverifiable: %s", KRB4_SERVICE_NAME, krb_err_txt[r]); - goto kerberos_auth_failure; + goto failure; } } else if (r == KDC_PR_UNKNOWN) { /* * Disallow login if no rcmd service exists, and * log the error. */ - log("Kerberos V4 TGT for %s unverifiable: %s; %s.%s " + log("Kerberos v4 TGT for %s unverifiable: %s; %s.%s " "not registered, or srvtab is wrong?", pw->pw_name, - krb_err_txt[r], KRB4_SERVICE_NAME, phost); - goto kerberos_auth_failure; + krb_err_txt[r], KRB4_SERVICE_NAME, phost); + goto failure; } else { /* * TGT is bad, forget it. Possibly spoofed! */ - packet_send_debug("WARNING: Kerberos V4 TGT " - "possibly spoofed for %s: %s", - pw->pw_name, krb_err_txt[r]); - goto kerberos_auth_failure; + debug("WARNING: Kerberos v4 TGT possibly spoofed " + "for %s: %s", pw->pw_name, krb_err_txt[r]); + goto failure; } - /* Authentication succeeded. */ - return 1; + return (1); + } else + /* Logging in as root or no local Kerberos realm. */ + debug("Unable to authenticate to Kerberos."); -kerberos_auth_failure: - krb4_cleanup_proc(NULL); + failure: + krb4_cleanup_proc(authctxt); + + if (!options.kerberos_or_local_passwd) + return (0); - if (!options.kerberos_or_local_passwd) - return 0; - } else { - /* Logging in as root or no local Kerberos realm. */ - packet_send_debug("Unable to authenticate to Kerberos."); - } /* Fall back to ordinary passwd authentication. */ - return -1; + return (-1); } void -krb4_cleanup_proc(void *ignore) +krb4_cleanup_proc(void *context) { + Authctxt *authctxt = (Authctxt *)context; debug("krb4_cleanup_proc called"); - if (ticket) { + if (authctxt->krb4_ticket_file) { (void) dest_tkt(); - xfree(ticket); - ticket = NULL; + xfree(authctxt->krb4_ticket_file); + authctxt->krb4_ticket_file = NULL; } } int -krb4_init(uid_t uid) -{ - static int cleanup_registered = 0; - const char *tkt_root = TKT_ROOT; - struct stat st; - int fd; - - if (!ticket) { - /* Set unique ticket string manually since we're still root. */ - ticket = xmalloc(MAXPATHLEN); -#ifdef AFS - if (lstat("/ticket", &st) != -1) - tkt_root = "/ticket/"; -#endif /* AFS */ - snprintf(ticket, MAXPATHLEN, "%s%d_%d", tkt_root, uid, getpid()); - (void) krb_set_tkt_string(ticket); - } - /* Register ticket cleanup in case of fatal error. */ - if (!cleanup_registered) { - fatal_add_cleanup(krb4_cleanup_proc, NULL); - cleanup_registered = 1; - } - /* Try to create our ticket file. */ - if ((fd = mkstemp(ticket)) != -1) { - close(fd); - return 1; - } - /* Ticket file exists - make sure user owns it (just passed ticket). */ - if (lstat(ticket, &st) != -1) { - if (st.st_mode == (S_IFREG | S_IRUSR | S_IWUSR) && - st.st_uid == uid) - return 1; - } - /* Failure - cancel cleanup function, leaving bad ticket for inspection. */ - log("WARNING: bad ticket file %s", ticket); - fatal_remove_cleanup(krb4_cleanup_proc, NULL); - cleanup_registered = 0; - xfree(ticket); - ticket = NULL; - - return 0; -} - -int -auth_krb4(const char *server_user, KTEXT auth, char **client) +auth_krb4(Authctxt *authctxt, KTEXT auth, char **client) { AUTH_DAT adat = {0}; KTEXT_ST reply; + Key_schedule schedule; + struct sockaddr_in local, foreign; char instance[INST_SZ]; - int r, s; socklen_t slen; u_int cksum; - Key_schedule schedule; - struct sockaddr_in local, foreign; + int r, s; s = packet_get_connection_in(); @@ -211,9 +237,10 @@ auth_krb4(const char *server_user, KTEXT auth, char **client) instance[1] = 0; /* Get the encrypted request, challenge, and session key. */ - if ((r = krb_rd_req(auth, KRB4_SERVICE_NAME, instance, 0, &adat, ""))) { - packet_send_debug("Kerberos V4 krb_rd_req: %.100s", krb_err_txt[r]); - return 0; + if ((r = krb_rd_req(auth, KRB4_SERVICE_NAME, instance, + 0, &adat, ""))) { + debug("Kerberos v4 krb_rd_req: %.100s", krb_err_txt[r]); + return (0); } des_key_sched((des_cblock *) adat.session, schedule); @@ -222,12 +249,11 @@ auth_krb4(const char *server_user, KTEXT auth, char **client) *adat.pinst ? "." : "", adat.pinst, adat.prealm); /* Check ~/.klogin authorization now. */ - if (kuserok(&adat, (char *) server_user) != KSUCCESS) { - packet_send_debug("Kerberos V4 .klogin authorization failed!"); - log("Kerberos V4 .klogin authorization failed for %s to account %s", - *client, server_user); + if (kuserok(&adat, authctxt->user) != KSUCCESS) { + log("Kerberos v4 .klogin authorization failed for %s to " + "account %s", *client, authctxt->user); xfree(*client); - return 0; + return (0); } /* Increment the checksum, and return it encrypted with the session key. */ @@ -238,7 +264,7 @@ auth_krb4(const char *server_user, KTEXT auth, char **client) empty message, admitting our failure. */ if ((r = krb_mk_priv((u_char *) & cksum, reply.dat, sizeof(cksum) + 1, schedule, &adat.session, &local, &foreign)) < 0) { - packet_send_debug("Kerberos V4 mk_priv: (%d) %s", r, krb_err_txt[r]); + debug("Kerberos v4 mk_priv: (%d) %s", r, krb_err_txt[r]); reply.dat[0] = 0; reply.length = 0; } else @@ -251,103 +277,97 @@ auth_krb4(const char *server_user, KTEXT auth, char **client) packet_put_string((char *) reply.dat, reply.length); packet_send(); packet_write_wait(); - return 1; + return (1); } #endif /* KRB4 */ #ifdef AFS int -auth_kerberos_tgt(struct passwd *pw, const char *string) +auth_krb4_tgt(Authctxt *authctxt, const char *string) { CREDENTIALS creds; + struct passwd *pw; + + if ((pw = authctxt->pw) == NULL) + goto failure; + + temporarily_use_uid(pw); if (!radix_to_creds(string, &creds)) { - log("Protocol error decoding Kerberos V4 tgt"); - packet_send_debug("Protocol error decoding Kerberos V4 tgt"); - goto auth_kerberos_tgt_failure; + log("Protocol error decoding Kerberos v4 TGT"); + goto failure; } if (strncmp(creds.service, "", 1) == 0) /* backward compatibility */ strlcpy(creds.service, "krbtgt", sizeof creds.service); if (strcmp(creds.service, "krbtgt")) { - log("Kerberos V4 tgt (%s%s%s@%s) rejected for %s", creds.pname, - creds.pinst[0] ? "." : "", creds.pinst, creds.realm, - pw->pw_name); - packet_send_debug("Kerberos V4 tgt (%s%s%s@%s) rejected for %s", + log("Kerberos v4 TGT (%s%s%s@%s) rejected for %s", creds.pname, creds.pinst[0] ? "." : "", creds.pinst, creds.realm, pw->pw_name); - goto auth_kerberos_tgt_failure; + goto failure; } - if (!krb4_init(pw->pw_uid)) - goto auth_kerberos_tgt_failure; + if (!krb4_init(authctxt)) + goto failure; if (in_tkt(creds.pname, creds.pinst) != KSUCCESS) - goto auth_kerberos_tgt_failure; + goto failure; if (save_credentials(creds.service, creds.instance, creds.realm, - creds.session, creds.lifetime, creds.kvno, - &creds.ticket_st, creds.issue_date) != KSUCCESS) { - packet_send_debug("Kerberos V4 tgt refused: couldn't save credentials"); - goto auth_kerberos_tgt_failure; + creds.session, creds.lifetime, creds.kvno, &creds.ticket_st, + creds.issue_date) != KSUCCESS) { + debug("Kerberos v4 TGT refused: couldn't save credentials"); + goto failure; } /* Successful authentication, passed all checks. */ chown(tkt_string(), pw->pw_uid, pw->pw_gid); - packet_send_debug("Kerberos V4 tgt accepted (%s.%s@%s, %s%s%s@%s)", - creds.service, creds.instance, creds.realm, creds.pname, - creds.pinst[0] ? "." : "", creds.pinst, creds.realm); + debug("Kerberos v4 TGT accepted (%s%s%s@%s)", + creds.pname, creds.pinst[0] ? "." : "", creds.pinst, creds.realm); memset(&creds, 0, sizeof(creds)); - packet_start(SSH_SMSG_SUCCESS); - packet_send(); - packet_write_wait(); - return 1; -auth_kerberos_tgt_failure: - krb4_cleanup_proc(NULL); + restore_uid(); + + return (1); + + failure: + krb4_cleanup_proc(authctxt); memset(&creds, 0, sizeof(creds)); - packet_start(SSH_SMSG_FAILURE); - packet_send(); - packet_write_wait(); - return 0; + restore_uid(); + + return (0); } int -auth_afs_token(struct passwd *pw, const char *token_string) +auth_afs_token(Authctxt *authctxt, const char *token_string) { CREDENTIALS creds; - uid_t uid = pw->pw_uid; + struct passwd *pw; + uid_t uid; + + if ((pw = authctxt->pw) == NULL) + return (0); if (!radix_to_creds(token_string, &creds)) { log("Protocol error decoding AFS token"); - packet_send_debug("Protocol error decoding AFS token"); - packet_start(SSH_SMSG_FAILURE); - packet_send(); - packet_write_wait(); - return 0; + return (0); } if (strncmp(creds.service, "", 1) == 0) /* backward compatibility */ strlcpy(creds.service, "afs", sizeof creds.service); if (strncmp(creds.pname, "AFS ID ", 7) == 0) uid = atoi(creds.pname + 7); + else + uid = pw->pw_uid; if (kafs_settoken(creds.realm, uid, &creds)) { - log("AFS token (%s@%s) rejected for %s", creds.pname, creds.realm, - pw->pw_name); - packet_send_debug("AFS token (%s@%s) rejected for %s", creds.pname, - creds.realm, pw->pw_name); + log("AFS token (%s@%s) rejected for %s", + creds.pname, creds.realm, pw->pw_name); memset(&creds, 0, sizeof(creds)); - packet_start(SSH_SMSG_FAILURE); - packet_send(); - packet_write_wait(); - return 0; + return (0); } - packet_send_debug("AFS token accepted (%s@%s, %s@%s)", creds.service, - creds.realm, creds.pname, creds.realm); + debug("AFS token accepted (%s@%s)", creds.pname, creds.realm); memset(&creds, 0, sizeof(creds)); - packet_start(SSH_SMSG_SUCCESS); - packet_send(); - packet_write_wait(); - return 1; + + return (1); } #endif /* AFS */