1 files changed, 209 insertions, 0 deletions

diff --git a/auth-krb4.c b/auth-krb4.c
new file mode 100644
index 000000000..720f3a4c4
--- /dev/null
+++ b/auth-krb4.c
@@ -0,0 +1,209 @@
+/*
+
+   auth-kerberos.c
+
+   Dug Song <dugsong@UMICH.EDU>
+
+   Kerberos v4 authentication and ticket-passing routines.
+
+   $Id: auth-krb4.c,v 1.1 1999/10/27 03:42:43 damien Exp $
+*/
+
+#include "includes.h"
+#include "packet.h"
+#include "xmalloc.h"
+#include "ssh.h"
+
+#ifdef KRB4
+int ssh_tf_init(uid_t uid)
+{
+  extern char *ticket;
+  char *tkt_root = TKT_ROOT;
+  struct stat st;
+  int fd;
+  
+  /* 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);
+
+  /* Make sure we own this ticket file, and we created it. */
+  if (lstat(ticket, &st) == -1 && errno == ENOENT) {
+    /* good, no ticket file exists. create it. */
+    if ((fd = open(ticket, O_RDWR|O_CREAT|O_EXCL, 0600)) != -1) {
+      close(fd);
+      return 1;
+    }
+  }
+  else {
+    /* file exists. make sure server_user owns it (e.g. just passed ticket),
+       and that it isn't a symlink, and that it is mode 600. */
+    if (st.st_mode == (S_IFREG|S_IRUSR|S_IWUSR) && st.st_uid == uid)
+      return 1;
+  }
+  /* Failure. */
+  log("WARNING: bad ticket file %s", ticket);
+  return 0;
+}
+
+int auth_krb4(const char *server_user, KTEXT auth, char **client)
+{
+  AUTH_DAT adat   = { 0 };
+  KTEXT_ST reply;
+  char instance[INST_SZ];
+  int r, s;
+  u_int cksum;
+  Key_schedule schedule;
+  struct sockaddr_in local, foreign;
+  
+  s = packet_get_connection_in();
+  
+  r = sizeof(local);
+  memset(&local, 0, sizeof(local));
+  if (getsockname(s, (struct sockaddr *) &local, &r) < 0)
+    debug("getsockname failed: %.100s", strerror(errno));
+  r = sizeof(foreign);
+  memset(&foreign, 0, sizeof(foreign));
+  if (getpeername(s, (struct sockaddr *)&foreign, &r) < 0)
+    debug("getpeername failed: %.100s", strerror(errno));
+  
+  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, ""))) {
+    packet_send_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, (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);
+    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) {
+    packet_send_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));
+  
+  packet_start(SSH_SMSG_AUTH_KERBEROS_RESPONSE);
+  packet_put_string((char *) reply.dat, reply.length);
+  packet_send();
+  packet_write_wait();
+  return 1;
+}
+#endif /* KRB4 */
+
+#ifdef AFS
+int auth_kerberos_tgt(struct passwd *pw, const char *string)
+{
+  CREDENTIALS creds;
+  extern char *ticket;
+  int r;
+  
+  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;
+  }
+  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 uid %d",
+        creds.pname, creds.pinst[0] ? "." : "", creds.pinst, creds.realm,
+        pw->pw_uid);
+    packet_send_debug("Kerberos V4 tgt (%s%s%s@%s) rejected for uid %d",
+                      creds.pname, creds.pinst[0] ? "." : "", creds.pinst,
+                      creds.realm, pw->pw_uid);
+    goto auth_kerberos_tgt_failure;
+  }
+  if (!ssh_tf_init(pw->pw_uid) ||
+      (r = in_tkt(creds.pname, creds.pinst)) ||
+      (r = save_credentials(creds.service, creds.instance, creds.realm,
+                            creds.session, creds.lifetime, creds.kvno,
+                            &creds.ticket_st, creds.issue_date))) {
+    xfree(ticket);
+    ticket = NULL;
+    packet_send_debug("Kerberos V4 tgt refused: couldn't save credentials");
+    goto auth_kerberos_tgt_failure;
+  }
+  /* Successful authentication, passed all checks. */
+  chown(ticket, 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);
+  
+  packet_start(SSH_SMSG_SUCCESS);
+  packet_send();
+  packet_write_wait();
+  return 1;
+
+auth_kerberos_tgt_failure:
+  memset(&creds, 0, sizeof(creds));
+  packet_start(SSH_SMSG_FAILURE);
+  packet_send();
+  packet_write_wait();
+  return 0;
+}
+
+int auth_afs_token(char *server_user, uid_t uid, const char *string)
+{
+  CREDENTIALS creds;
+
+  if (!radix_to_creds(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;
+  }
+  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);
+  
+  if (kafs_settoken(creds.realm, uid, &creds)) {
+    log("AFS token (%s@%s) rejected for uid %d", creds.pname,
+        creds.realm, uid);
+    packet_send_debug("AFS token (%s@%s) rejected for uid %d", creds.pname,
+                      creds.realm, uid);
+    packet_start(SSH_SMSG_FAILURE);
+    packet_send();
+    packet_write_wait();
+    return 0;
+  }
+  packet_send_debug("AFS token accepted (%s@%s, %s@%s)", creds.service,
+                    creds.realm, creds.pname, creds.realm);
+  packet_start(SSH_SMSG_SUCCESS);
+  packet_send();
+  packet_write_wait();
+  return 1;
+}
+#endif /* AFS */