Import OpenSSH 3.8p1.

1 files changed, 368 insertions, 0 deletions

diff --git a/auth-krb4.c b/auth-krb4.c
new file mode 100644
index 000000000..b28df469f
--- /dev/null
+++ b/auth-krb4.c
@@ -0,0 +1,368 @@
+/*
+ * 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 1.29 2003/02/21 10:34:48 mpech Exp $");
+
+#include "ssh.h"
+#include "ssh1.h"
+#include "packet.h"
+#include "xmalloc.h"
+#include "log.h"
+#include "servconf.h"
+#include "uidswap.h"
+#include "auth.h"
+
+#ifdef AFS
+#include "radix.h"
+#endif
+
+#ifdef KRB4
+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_%ld",
+                    tkt_root, authctxt->pw->pw_uid, (long)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(Authctxt *authctxt, const char *password)
+{
+        AUTH_DAT adata;
+        KTEXT_ST tkt;
+        struct hostent *hp;
+        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(authctxt)) {
+                        log("Couldn't initialize Kerberos ticket file for %s!",
+                            pw->pw_name);
+                        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);
+                if (r != INTK_OK) {
+                        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);
+
+                /*
+                 * Now that we have a TGT, try to get a local
+                 * "rcmd" ticket to ensure that we are not talking
+                 * to a bogus Kerberos server.
+                 */
+                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)) == NULL) {
+                                log("Couldn't get local host address!");
+                                goto failure;
+                        }
+                        memmove((void *)&faddr, (void *)hp->h_addr,
+                            sizeof(faddr));
+
+                        /* Verify our "rcmd" ticket. */
+                        r = krb_rd_req(&tkt, KRB4_SERVICE_NAME, phost,
+                            faddr, &adata, "");
+                        if (r == RD_AP_UNDEC) {
+                                /*
+                                 * Probably didn't have a srvtab on
+                                 * localhost. Disallow login.
+                                 */
+                                log("Kerberos v4 TGT for %s unverifiable, "
+                                    "no srvtab installed? krb_rd_req: %s",
+                                    pw->pw_name, krb_err_txt[r]);
+                                goto failure;
+                        } else if (r != KSUCCESS) {
+                                log("Kerberos v4 %s ticket unverifiable: %s",
+                                    KRB4_SERVICE_NAME, krb_err_txt[r]);
+                                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 "
+                            "not registered, or srvtab is wrong?", pw->pw_name,
+                            krb_err_txt[r], KRB4_SERVICE_NAME, phost);
+                        goto failure;
+                } else {
+                        /*
+                         * TGT is bad, forget it. Possibly spoofed!
+                         */
+                        debug("WARNING: Kerberos v4 TGT possibly spoofed "
+                            "for %s: %s", pw->pw_name, krb_err_txt[r]);
+                        goto failure;
+                }
+                /* Authentication succeeded. */
+                return (1);
+        } else
+                /* Logging in as root or no local Kerberos realm. */
+                debug("Unable to authenticate to Kerberos.");
+
+ failure:
+        krb4_cleanup_proc(authctxt);
+
+        if (!options.kerberos_or_local_passwd)
+                return (0);
+
+        /* Fall back to ordinary passwd authentication. */
+        return (-1);
+}
+
+void
+krb4_cleanup_proc(void *context)
+{
+        Authctxt *authctxt = (Authctxt *)context;
+        debug("krb4_cleanup_proc called");
+        if (authctxt->krb4_ticket_file) {
+                (void) dest_tkt();
+                xfree(authctxt->krb4_ticket_file);
+                authctxt->krb4_ticket_file = NULL;
+        }
+}
+
+int
+auth_krb4(Authctxt *authctxt, KTEXT auth, char **client, KTEXT reply)
+{
+        AUTH_DAT adat = {0};
+        Key_schedule schedule;
+        struct sockaddr_in local, foreign;
+        char instance[INST_SZ];
+        socklen_t slen;
+        u_int cksum;
+        int r, s;
+
+        s = packet_get_connection_in();
+
+        slen = sizeof(local);
+        memset(&local, 0, sizeof(local));
+        if (getsockname(s, (struct sockaddr *) & local, &slen) < 0)
+                debug("getsockname failed: %.100s", strerror(errno));
+        slen = sizeof(foreign);
+        memset(&foreign, 0, sizeof(foreign));
+        if (getpeername(s, (struct sockaddr *) & foreign, &slen) < 0) {
+                debug("getpeername failed: %.100s", strerror(errno));
+                fatal_cleanup();
+        }
+        instance[0] = '*';
+        instance[1] = 0;
+
+        /* Get the encrypted request, challenge, and session key. */
+        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);
+
+        *client = xmalloc(MAX_K_NAME_SZ);
+        (void) snprintf(*client, MAX_K_NAME_SZ, "%s%s%s@%s", adat.pname,
+            *adat.pinst ? "." : "", adat.pinst, adat.prealm);
+
+        /* Check ~/.klogin authorization now. */
+        if (kuserok(&adat, authctxt->user) != KSUCCESS) {
+                log("Kerberos v4 .klogin authorization failed for %s to "
+                    "account %s", *client, authctxt->user);
+                xfree(*client);
+                *client = NULL;
+                return (0);
+        }
+        /* Increment the checksum, and return it encrypted with the
+           session key. */
+        cksum = adat.checksum + 1;
+        cksum = htonl(cksum);
+
+        /* If we can't successfully encrypt the checksum, we send back an
+           empty message, admitting our failure. */
+        if ((r = krb_mk_priv((u_char *) & cksum, reply->dat, sizeof(cksum) + 1,
+            schedule, &adat.session, &local, &foreign)) < 0) {
+                debug("Kerberos v4 mk_priv: (%d) %s", r, krb_err_txt[r]);
+                reply->dat[0] = 0;
+                reply->length = 0;
+        } else
+                reply->length = r;
+
+        /* Clear session key. */
+        memset(&adat.session, 0, sizeof(adat.session));
+        return (1);
+}
+#endif /* KRB4 */
+
+#ifdef AFS
+int
+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");
+                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);
+                goto failure;
+        }
+        if (!krb4_init(authctxt))
+                goto failure;
+
+        if (in_tkt(creds.pname, creds.pinst) != KSUCCESS)
+                goto failure;
+
+        if (save_credentials(creds.service, creds.instance, creds.realm,
+            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);
+
+        debug("Kerberos v4 TGT accepted (%s%s%s@%s)",
+            creds.pname, creds.pinst[0] ? "." : "", creds.pinst, creds.realm);
+        memset(&creds, 0, sizeof(creds));
+
+        restore_uid();
+
+        return (1);
+
+ failure:
+        krb4_cleanup_proc(authctxt);
+        memset(&creds, 0, sizeof(creds));
+        restore_uid();
+
+        return (0);
+}
+
+int
+auth_afs_token(Authctxt *authctxt, const char *token_string)
+{
+        CREDENTIALS creds;
+        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");
+                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);
+                memset(&creds, 0, sizeof(creds));
+                return (0);
+        }
+        debug("AFS token accepted (%s@%s)", creds.pname, creds.realm);
+        memset(&creds, 0, sizeof(creds));
+
+        return (1);
+}
+#endif /* AFS */