]> andersk Git - gssapi-openssh.git/blobdiff - openssh/gss-serv.c
updated patch from Matthieu Hautreux for cascading credentials
[gssapi-openssh.git] / openssh / gss-serv.c
index b94472eaf34fae2e286ecd7ea64b50ccd735c874..7cbf8e2f89b82b7ad18fcbb88a5c1621e9934a68 100644 (file)
@@ -1,5 +1,7 @@
+/* $OpenBSD: gss-serv.c,v 1.22 2008/05/08 12:02:23 djm Exp $ */
+
 /*
- * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
+ * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
 
 #ifdef GSSAPI
 
-#include "ssh.h"
-#include "ssh2.h"
+#include <sys/types.h>
+#include <sys/param.h>
+
+#include <stdarg.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "openbsd-compat/sys-queue.h"
 #include "xmalloc.h"
 #include "buffer.h"
-#include "bufaux.h"
-#include "packet.h"
-#include "compat.h"
-#include <openssl/evp.h>
-#include "cipher.h"
-#include "kex.h"
+#include "key.h"
+#include "hostfile.h"
 #include "auth.h"
 #include "log.h"
 #include "channels.h"
 #include "session.h"
-#include "dispatch.h"
+#include "misc.h"
 #include "servconf.h"
-#include "compat.h"
-#include "monitor_wrap.h"
+#include "uidswap.h"
 
+#include "xmalloc.h"
 #include "ssh-gss.h"
+#include "monitor_wrap.h"
 
 extern ServerOptions options;
-extern u_char *session_id2;
-extern int session_id2_len;
+extern Authctxt *the_authctxt;
 
 static ssh_gssapi_client gssapi_client =
-       { {0,NULL}, GSS_C_NO_CREDENTIAL, NULL, {NULL,NULL,NULL}};
+    { GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER,
+    GSS_C_NO_CREDENTIAL, GSS_C_NO_NAME,  NULL, {NULL, NULL, NULL}, 0, 0};
 
-ssh_gssapi_mech gssapi_null_mech 
-  = {NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL};
+ssh_gssapi_mech gssapi_null_mech =
+    { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL, NULL};
 
 #ifdef KRB5
 extern ssh_gssapi_mech gssapi_kerberos_mech;
-extern ssh_gssapi_mech gssapi_kerberos_mech_old;
 #endif
 #ifdef GSI
 extern ssh_gssapi_mech gssapi_gsi_mech;
-extern ssh_gssapi_mech gssapi_gsi_mech_old;
 #endif
 
 ssh_gssapi_mech* supported_mechs[]= {
 #ifdef KRB5
-  &gssapi_kerberos_mech,
-  &gssapi_kerberos_mech_old, /* Support for legacy clients */
+       &gssapi_kerberos_mech,
 #endif
 #ifdef GSI
-  &gssapi_gsi_mech,
-  &gssapi_gsi_mech_old,        /* Support for legacy clients */
+       &gssapi_gsi_mech,
 #endif
-  &gssapi_null_mech,
+       &gssapi_null_mech,
 };
 
-/* Return a list of the gss-group1-sha1-x mechanisms supported by this
- * program.
- *
- * We only support the mechanisms that we've indicated in the list above,
- * but we check that they're supported by the GSSAPI mechanism on the 
- * machine. We also check, before including them in the list, that
- * we have the necesary information in order to carry out the key exchange
- * (that is, that the user has credentials, the server's creds are accessible,
- * etc)
- *
- * The way that this is done is fairly nasty, as we do a lot of work that
- * is then thrown away. This should possibly be implemented with a cache
- * that stores the results (in an expanded Gssctxt structure), which are
- * then used by the first calls if that key exchange mechanism is chosen.
+#ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
+static int limited = 0;
+#endif
+
+/*
+ * Acquire credentials for a server running on the current host.
+ * Requires that the context structure contains a valid OID
  */
-char * 
-ssh_gssapi_server_mechanisms() {
-       gss_OID_set     supported;
-       Gssctxt         *ctx = NULL;
-       OM_uint32       maj_status, min_status;
-       Buffer          buf;
-       int             i = 0;
-       int             first = 0;
-       int             present;
-       char *          mechs;
-
-       if (datafellows & SSH_OLD_GSSAPI) return NULL;
-       
-       ssh_gssapi_supported_oids(&supported);
-       
-       buffer_init(&buf);
-
-       while(supported_mechs[i]->name != NULL) {
-               if ((maj_status=gss_test_oid_set_member(&min_status,
-                                                       &supported_mechs[i]->oid,
-                                                       supported,
-                                                       &present))) {
-                       present=0;
+
+/* Returns a GSSAPI error code */
+/* Privileged (called from ssh_gssapi_server_ctx) */
+static OM_uint32
+ssh_gssapi_acquire_cred(Gssctxt *ctx)
+{
+       OM_uint32 status;
+       char lname[MAXHOSTNAMELEN];
+       gss_OID_set oidset;
+
+       if (options.gss_strict_acceptor) {
+               gss_create_empty_oid_set(&status, &oidset);
+               gss_add_oid_set_member(&status, ctx->oid, &oidset);
+
+               if (gethostname(lname, MAXHOSTNAMELEN)) {
+                       gss_release_oid_set(&status, &oidset);
+                       return (-1);
                }
 
-               if (present) {
-                   if (!GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctx,
-                                          &supported_mechs[i]->oid)))) {
-                       /* Append gss_group1_sha1_x to our list */
-                       if (first++!=0)
-                               buffer_put_char(&buf,',');
-                       buffer_append(&buf, KEX_GSS_SHA1,
-                                     sizeof(KEX_GSS_SHA1)-1);
-                       buffer_append(&buf, 
-                                     supported_mechs[i]->enc_name,
-                                     strlen(supported_mechs[i]->enc_name));
-                       debug("GSSAPI mechanism %s (%s%s) supported",
-                             supported_mechs[i]->name, KEX_GSS_SHA1,
-                             supported_mechs[i]->enc_name);
-                   } else {
-                       debug("no credentials for GSSAPI mechanism %s",
-                             supported_mechs[i]->name);
-                   }
-               } else {
-                   debug("GSSAPI mechanism %s not supported",
-                         supported_mechs[i]->name);
+               if (GSS_ERROR(ssh_gssapi_import_name(ctx, lname))) {
+                       gss_release_oid_set(&status, &oidset);
+                       return (ctx->major);
                }
-               ssh_gssapi_delete_ctx(&ctx);
-               i++;
+
+               if ((ctx->major = gss_acquire_cred(&ctx->minor,
+                   ctx->name, 0, oidset, GSS_C_ACCEPT, &ctx->creds, 
+                   NULL, NULL)))
+                       ssh_gssapi_error(ctx);
+
+               gss_release_oid_set(&status, &oidset);
+               return (ctx->major);
+       } else {
+               ctx->name = GSS_C_NO_NAME;
+               ctx->creds = GSS_C_NO_CREDENTIAL;
        }
-       
-       buffer_put_char(&buf,'\0');
-       
-       mechs=xmalloc(buffer_len(&buf));
-       buffer_get(&buf,mechs,buffer_len(&buf));
-       buffer_free(&buf);
-       if (strlen(mechs)==0)
-          return(NULL);
-       else
-          return(mechs);
+       return GSS_S_COMPLETE;
+}
+
+/* Privileged */
+OM_uint32
+ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID oid)
+{
+       if (*ctx)
+               ssh_gssapi_delete_ctx(ctx);
+       ssh_gssapi_build_ctx(ctx);
+       ssh_gssapi_set_oid(*ctx, oid);
+       return (ssh_gssapi_acquire_cred(*ctx));
 }
 
-void ssh_gssapi_supported_oids(gss_OID_set *oidset) {
-       int i =0;
-       OM_uint32 maj_status,min_status;
+/* Unprivileged */
+char *
+ssh_gssapi_server_mechanisms() {
+       gss_OID_set     supported;
+
+       ssh_gssapi_supported_oids(&supported);
+       return (ssh_gssapi_kex_mechs(supported, &ssh_gssapi_server_check_mech,
+           NULL, NULL));
+}
+
+/* Unprivileged */
+int
+ssh_gssapi_server_check_mech(Gssctxt **dum, gss_OID oid, const char *data,
+    const char *dummy) {
+       Gssctxt *ctx = NULL;
+       int res;
+       res = !GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctx, oid)));
+       ssh_gssapi_delete_ctx(&ctx);
+
+       return (res);
+}
+
+/* Unprivileged */
+void
+ssh_gssapi_supported_oids(gss_OID_set *oidset)
+{
+       int i = 0;
+       OM_uint32 min_status;
        int present;
        gss_OID_set supported;
-       
-       gss_create_empty_oid_set(&min_status,oidset);
-       PRIVSEP(gss_indicate_mechs(&min_status, &supported));
-
-       while (supported_mechs[i]->name!=NULL) {
-               if ((maj_status=gss_test_oid_set_member(&min_status,
-                                                      &supported_mechs[i]->oid,
-                                                      supported,
-                                                      &present))) {
-                       present=0;
-               }
-               if (present) {
+
+       gss_create_empty_oid_set(&min_status, oidset);
+
+       /* Ask privileged process what mechanisms it supports. */
+       if (GSS_ERROR(PRIVSEP(gss_indicate_mechs(&min_status, &supported))))
+               return;
+
+       while (supported_mechs[i]->name != NULL) {
+               if (GSS_ERROR(gss_test_oid_set_member(&min_status,
+                   &supported_mechs[i]->oid, supported, &present)))
+                       present = 0;
+               if (present)
                        gss_add_oid_set_member(&min_status,
-                                              &supported_mechs[i]->oid,
-                                              oidset); 
-               }
+                           &supported_mechs[i]->oid, oidset);
                i++;
        }
-}      
 
-/* Find out which GSS type (out of the list we define in ssh-gss.h) a
- * particular connection is using 
- */
-ssh_gssapi_mech *
-ssh_gssapi_get_ctype(Gssctxt *ctxt) {
-       int i=0;
-       
-       while(supported_mechs[i]->name!=NULL) {
-           if (supported_mechs[i]->oid.length == ctxt->oid->length &&
-               (memcmp(supported_mechs[i]->oid.elements,
-                       ctxt->oid->elements,ctxt->oid->length)==0)) {
-               return supported_mechs[i];
-           }
-           i++;
-       }
-       return NULL;
+       gss_release_oid_set(&min_status, &supported);
 }
 
-/* Set the GSS context's OID to the oid indicated by the given key exchange
- * name. */
-gss_OID 
-ssh_gssapi_id_kex(Gssctxt *ctx, char *name) {
-  int i=0;
-  
-  if (strncmp(name, KEX_GSS_SHA1, sizeof(KEX_GSS_SHA1)-1) !=0) {
-     return(NULL);
-  }
-  
-  name+=sizeof(KEX_GSS_SHA1)-1; /* Move to the start of the MIME string */
-  
-  while (supported_mechs[i]->name!=NULL &&
-       strcmp(name,supported_mechs[i]->enc_name)!=0) {
-       i++;
-  }
-
-  if (supported_mechs[i]->name==NULL)
-     return (NULL);
-
-  if (ctx) ssh_gssapi_set_oid(ctx,&supported_mechs[i]->oid);
-
-  debug("using GSSAPI mechanism %s (%s%s)", supported_mechs[i]->name,
-       KEX_GSS_SHA1, supported_mechs[i]->enc_name);
-
-  return &supported_mechs[i]->oid;
-}
 
-/* Wrapper arround accept_sec_context
+/* Wrapper around accept_sec_context
  * Requires that the context contains:
- *    oid              
+ *    oid
  *    credentials      (from ssh_gssapi_acquire_cred)
  */
-OM_uint32 ssh_gssapi_accept_ctx(Gssctxt *ctx,gss_buffer_desc *recv_tok,
-                               gss_buffer_desc *send_tok, OM_uint32 *flags) 
+/* Privileged */
+OM_uint32
+ssh_gssapi_accept_ctx(Gssctxt *ctx, gss_buffer_desc *recv_tok,
+    gss_buffer_desc *send_tok, OM_uint32 *flags)
 {
        OM_uint32 status;
        gss_OID mech;
-       
-       ctx->major=gss_accept_sec_context(&ctx->minor,
-                                         &ctx->context,
-                                         ctx->creds,
-                                         recv_tok,
-                                         GSS_C_NO_CHANNEL_BINDINGS,
-                                         &ctx->client,
-                                         &mech, /* read-only pointer */
-                                         send_tok,
-                                         flags,
-                                         NULL,
-                                         &ctx->client_creds);
-       if (GSS_ERROR(ctx->major)) {
+
+       ctx->major = gss_accept_sec_context(&ctx->minor,
+           &ctx->context, ctx->creds, recv_tok,
+           GSS_C_NO_CHANNEL_BINDINGS, &ctx->client, &mech,
+           send_tok, flags, NULL, &ctx->client_creds);
+
+       if (GSS_ERROR(ctx->major))
                ssh_gssapi_error(ctx);
-       }
-       
-       if (ctx->client_creds) {
+
+       if (ctx->client_creds)
                debug("Received some client credentials");
-       } else {
+       else
                debug("Got no client credentials");
-       }
 
-       /* FIXME: We should check that the me
-       * the one that we asked for (in ctx->oid) */
+       status = ctx->major;
 
-       status=ctx->major;
-       
        /* Now, if we're complete and we have the right flags, then
-       * we flag the user as also having been authenticated
-       */
-       
-       if (((flags==NULL) || ((*flags & GSS_C_MUTUAL_FLAG) && 
-                              (*flags & GSS_C_INTEG_FLAG))) &&
-           (ctx->major == GSS_S_COMPLETE)) {
-               if (ssh_gssapi_getclient(ctx,&gssapi_client.mech,
-                                        &gssapi_client.name,
-                                        &gssapi_client.creds))
-                       fatal("Couldn't convert client name");
+        * we flag the user as also having been authenticated
+        */
+
+       if (((flags == NULL) || ((*flags & GSS_C_MUTUAL_FLAG) &&
+           (*flags & GSS_C_INTEG_FLAG))) && (ctx->major == GSS_S_COMPLETE)) {
+               if (ssh_gssapi_getclient(ctx, &gssapi_client))
+                       fatal("Couldn't convert client name");
+#ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
+               if (flags && (*flags & GSS_C_GLOBUS_LIMITED_PROXY_FLAG))
+                       limited=1;
+#endif
+       }
+
+       return (status);
+}
+
+/*
+ * This parses an exported name, extracting the mechanism specific portion
+ * to use for ACL checking. It verifies that the name belongs the mechanism
+ * originally selected.
+ */
+static OM_uint32
+ssh_gssapi_parse_ename(Gssctxt *ctx, gss_buffer_t ename, gss_buffer_t name)
+{
+       u_char *tok;
+       OM_uint32 offset;
+       OM_uint32 oidl;
+
+       tok = ename->value;
+
+#ifdef GSI /* GSI gss_export_name() is broken. */
+       if ((ctx->oid->length == gssapi_gsi_mech.oid.length) &&
+           (memcmp(ctx->oid->elements, gssapi_gsi_mech.oid.elements,
+                   gssapi_gsi_mech.oid.length) == 0)) {
+           name->length = ename->length;
+           name->value = xmalloc(ename->length+1);
+           memcpy(name->value, ename->value, ename->length);
+           return GSS_S_COMPLETE;
        }
+#endif
+
+       /*
+        * Check that ename is long enough for all of the fixed length
+        * header, and that the initial ID bytes are correct
+        */
+
+       if (ename->length < 6 || memcmp(tok, "\x04\x01", 2) != 0)
+               return GSS_S_FAILURE;
+
+       /*
+        * Extract the OID, and check it. Here GSSAPI breaks with tradition
+        * and does use the OID type and length bytes. To confuse things
+        * there are two lengths - the first including these, and the
+        * second without.
+        */
+
+       oidl = get_u16(tok+2); /* length including next two bytes */
+       oidl = oidl-2; /* turn it into the _real_ length of the variable OID */
+
+       /*
+        * Check the BER encoding for correct type and length, that the
+        * string is long enough and that the OID matches that in our context
+        */
+       if (tok[4] != 0x06 || tok[5] != oidl ||
+           ename->length < oidl+6 ||
+           !ssh_gssapi_check_oid(ctx, tok+6, oidl))
+               return GSS_S_FAILURE;
 
-       /* Make sure that the getclient call hasn't stamped on this */
-       return(status);
+       offset = oidl+6;
+
+       if (ename->length < offset+4)
+               return GSS_S_FAILURE;
+
+       name->length = get_u32(tok+offset);
+       offset += 4;
+
+       if (ename->length < offset+name->length)
+               return GSS_S_FAILURE;
+
+       name->value = xmalloc(name->length+1);
+       memcpy(name->value, tok+offset, name->length);
+       ((char *)name->value)[name->length] = 0;
+
+       return GSS_S_COMPLETE;
 }
 
 /* Extract the client details from a given context. This can only reliably
  * be called once for a context */
 
-OM_uint32 
-ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_mech **type,
-                    gss_buffer_desc *name, gss_cred_id_t *creds) {
+/* Privileged (called from accept_secure_ctx) */
+OM_uint32
+ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
+{
+       int i = 0;
+       int equal = 0;
+       gss_name_t new_name = GSS_C_NO_NAME;
+       gss_buffer_desc ename = GSS_C_EMPTY_BUFFER;
+
+       if (options.gss_store_rekey && client->used && ctx->client_creds) {
+               if (client->mech->oid.length != ctx->oid->length ||
+                   (memcmp(client->mech->oid.elements,
+                    ctx->oid->elements, ctx->oid->length) !=0)) {
+                       debug("Rekeyed credentials have different mechanism");
+                       return GSS_S_COMPLETE;
+               }
 
-       *type=ssh_gssapi_get_ctype(ctx);
-       if ((ctx->major=gss_display_name(&ctx->minor,ctx->client,name,NULL))) {
+        /* Call gss_inquire_cred rather than gss_inquire_cred_by_mech
+           because GSI doesn't support the latter. -jbasney */
+
+               if ((ctx->major = gss_inquire_cred(&ctx->minor, 
+                   ctx->client_creds, &new_name, 
+                   NULL, NULL, NULL))) {
+                       ssh_gssapi_error(ctx);
+                       return (ctx->major);
+               }
+
+               ctx->major = gss_compare_name(&ctx->minor, client->name, 
+                   new_name, &equal);
+
+               if (GSS_ERROR(ctx->major)) {
+                       ssh_gssapi_error(ctx);
+                       return (ctx->major);
+               }
+               if (!equal) {
+                       debug("Rekeyed credentials have different name");
+                       return GSS_S_COMPLETE;
+               }
+
+               debug("Marking rekeyed credentials for export");
+
+               gss_release_name(&ctx->minor, &client->name);
+               gss_release_cred(&ctx->minor, &client->creds);
+               client->name = new_name;
+               client->creds = ctx->client_creds;
+               ctx->client_creds = GSS_C_NO_CREDENTIAL;
+               client->updated = 1;
+               return GSS_S_COMPLETE;
+       }
+
+       client->mech = NULL;
+
+       while (supported_mechs[i]->name != NULL) {
+               if (supported_mechs[i]->oid.length == ctx->oid->length &&
+                   (memcmp(supported_mechs[i]->oid.elements,
+                   ctx->oid->elements, ctx->oid->length) == 0))
+                       client->mech = supported_mechs[i];
+               i++;
+       }
+
+       if (client->mech == NULL)
+               return GSS_S_FAILURE;
+
+    /* Call gss_inquire_cred rather than gss_inquire_cred_by_mech
+       because GSI doesn't support the latter. -jbasney */
+
+       if (ctx->client_creds &&
+           (ctx->major = gss_inquire_cred(&ctx->minor,
+            ctx->client_creds, &client->name, NULL, NULL, NULL))) {
+               ssh_gssapi_error(ctx);
+               return (ctx->major);
+       }
+
+       if ((ctx->major = gss_display_name(&ctx->minor, ctx->client,
+           &client->displayname, NULL))) {
+               ssh_gssapi_error(ctx);
+               return (ctx->major);
+       }
+
+       if ((ctx->major = gss_export_name(&ctx->minor, ctx->client,
+           &ename))) {
                ssh_gssapi_error(ctx);
-               return(ctx->major);
+               return (ctx->major);
        }
-       
-       /* This is icky. There appears to be no way to copy this structure,
-       * rather than the pointer to it, so we simply copy the pointer and
-       * mark the originator as empty so we don't destroy it. 
-       */
-       *creds=ctx->client_creds;
-       ctx->client_creds=GSS_C_NO_CREDENTIAL;
-       return(ctx->major);
+
+       if ((ctx->major = ssh_gssapi_parse_ename(ctx,&ename,
+           &client->exportedname))) {
+               return (ctx->major);
+       }
+
+       gss_release_buffer(&ctx->minor, &ename);
+
+       /* We can't copy this structure, so we just move the pointer to it */
+       client->creds = ctx->client_creds;
+       ctx->client_creds = GSS_C_NO_CREDENTIAL;
+
+    /* needed for globus_gss_assist_map_and_authorize() */
+    client->context = ctx->context;
+
+       return (ctx->major);
 }
 
+/* As user - called on fatal/exit */
 void
-ssh_gssapi_cleanup_creds(void *ignored)
+ssh_gssapi_cleanup_creds(void)
 {
-       if (gssapi_client.store.filename!=NULL) {
+       if (gssapi_client.store.filename != NULL) {
                /* Unlink probably isn't sufficient */
-               debug("removing gssapi cred file\"%s\"",gssapi_client.store.filename);
+               debug("removing gssapi cred file\"%s\"",
+                   gssapi_client.store.filename);
                unlink(gssapi_client.store.filename);
        }
 }
 
-void 
-ssh_gssapi_storecreds()
+/* As user */
+void
+ssh_gssapi_storecreds(void)
 {
        if (gssapi_client.mech && gssapi_client.mech->storecreds) {
+        if (options.gss_creds_path) {
+            gssapi_client.store.filename =
+                expand_authorized_keys(options.gss_creds_path,
+                                       the_authctxt->pw);
+        }
                (*gssapi_client.mech->storecreds)(&gssapi_client);
-               if (options.gss_cleanup_creds) {
-                       fatal_add_cleanup(ssh_gssapi_cleanup_creds, NULL);
-               }
-       } else {
+       } else
                debug("ssh_gssapi_storecreds: Not a GSSAPI mechanism");
-       }
 }
 
 /* This allows GSSAPI methods to do things to the childs environment based
  * on the passed authentication process and credentials.
- *
- * Question: If we didn't use userauth_external for some reason, should we
- * still delegate credentials?
  */
-void 
-ssh_gssapi_do_child(char ***envp, u_int *envsizep) 
+/* As user */
+void
+ssh_gssapi_do_child(char ***envp, u_int *envsizep)
 {
 
-       if (gssapi_client.store.envvar!=NULL && 
-           gssapi_client.store.envval!=NULL) {
-           
+       if (gssapi_client.store.envvar != NULL &&
+           gssapi_client.store.envval != NULL) {
                debug("Setting %s to %s", gssapi_client.store.envvar,
-                                         gssapi_client.store.envval);                            
-               child_set_env(envp, envsizep, gssapi_client.store.envvar, 
-                                             gssapi_client.store.envval);
+                   gssapi_client.store.envval);
+               child_set_env(envp, envsizep, gssapi_client.store.envvar,
+                   gssapi_client.store.envval);
        }
 }
 
+/* Privileged */
 int
-ssh_gssapi_userok(char *user)
+ssh_gssapi_userok(char *user, struct passwd *pw)
 {
-       if (gssapi_client.name.length==0 || 
-           gssapi_client.name.value==NULL) {
+       OM_uint32 lmin;
+
+       if (gssapi_client.exportedname.length == 0 ||
+           gssapi_client.exportedname.value == NULL) {
                debug("No suitable client data");
                return 0;
        }
-       if (gssapi_client.mech && gssapi_client.mech->userok) {
-               return((*gssapi_client.mech->userok)(&gssapi_client,user));
-       } else {
-               debug("ssh_gssapi_userok: Unknown GSSAPI mechanism");
+#ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
+       if (limited && options.gsi_allow_limited_proxy != 1) {
+               debug("limited proxy not acceptable for remote login");
+               return 0;
        }
-       return(0);
+#endif
+       if (gssapi_client.mech && gssapi_client.mech->userok)
+               if ((*gssapi_client.mech->userok)(&gssapi_client, user)) {
+                       gssapi_client.used = 1;
+                       gssapi_client.store.owner = pw;
+                       return 1;
+               } else {
+                       /* Destroy delegated credentials if userok fails */
+                       gss_release_buffer(&lmin, &gssapi_client.displayname);
+                       gss_release_buffer(&lmin, &gssapi_client.exportedname);
+                       gss_release_cred(&lmin, &gssapi_client.creds);
+                       memset(&gssapi_client, 0, sizeof(ssh_gssapi_client));
+                       return 0;
+               }
+       else
+               debug("ssh_gssapi_userok: Unknown GSSAPI mechanism");
+       return (0);
 }
 
+/* ssh_gssapi_checkmic() moved to gss-genr.c so it can be called by
+   kexgss_client(). */
+
+/* Priviledged */
 int
 ssh_gssapi_localname(char **user)
 {
        *user = NULL;
-       if (gssapi_client.name.length==0 || 
-           gssapi_client.name.value==NULL) {
+       if (gssapi_client.displayname.length==0 || 
+           gssapi_client.displayname.value==NULL) {
                debug("No suitable client data");
                return(0);;
        }
@@ -379,4 +508,104 @@ ssh_gssapi_localname(char **user)
        }
        return(0);
 }
+
+/* These bits are only used for rekeying. The unpriviledged child is running 
+ * as the user, the monitor is root.
+ *
+ * In the child, we want to :
+ *    *) Ask the monitor to store our credentials into the store we specify
+ *    *) If it succeeds, maybe do a PAM update
+ */
+
+/* Stuff for PAM */
+
+#ifdef USE_PAM
+static int ssh_gssapi_simple_conv(int n, const struct pam_message **msg, 
+    struct pam_response **resp, void *data)
+{
+       return (PAM_CONV_ERR);
+}
+#endif
+
+void
+ssh_gssapi_rekey_creds() {
+       int ok;
+#ifdef USE_PAM
+       int ret;
+       pam_handle_t *pamh = NULL;
+       struct pam_conv pamconv = {ssh_gssapi_simple_conv, NULL};
+       char *envstr;
+       char **p;char **pw;
+#endif
+
+       if (gssapi_client.store.filename == NULL && 
+           gssapi_client.store.envval == NULL &&
+           gssapi_client.store.envvar == NULL)
+               return;
+       ok = PRIVSEP(ssh_gssapi_update_creds(&gssapi_client.store));
+
+       if (!ok)
+               return;
+
+       debug("Rekeyed credentials stored successfully");
+
+       /* Actually managing to play with the ssh pam stack from here will
+        * be next to impossible. In any case, we may want different options
+        * for rekeying. So, use our own :)
+        */
+#ifdef USE_PAM 
+       if (!use_privsep) {
+               debug("Not even going to try and do PAM with privsep disabled");
+               return;
+       }
+
+       ret = pam_start("sshd-rekey", gssapi_client.store.owner->pw_name,
+           &pamconv, &pamh);
+       if (ret)
+               return;
+
+       /* Put ssh pam stack env variables in this new pam stack env 
+        * Using pam-pkinit, KRB5CCNAME is set during do_pam_session
+        * this addition enables pam-pkinit to access KRB5CCNAME if used 
+        * in sshd-rekey stack too
+        */
+       pw = p = fetch_pam_environment();
+       while ( *pw != NULL ) {
+               pam_putenv(pamh,*pw);
+               pw++;
+       }
+       free_pam_environment(p);
+
+       xasprintf(&envstr, "%s=%s", gssapi_client.store.envvar, 
+           gssapi_client.store.envval);
+
+       ret = pam_putenv(pamh, envstr);
+       if (!ret)
+               pam_setcred(pamh, PAM_REINITIALIZE_CRED);
+       pam_end(pamh, PAM_SUCCESS);
+#endif
+}
+
+int 
+ssh_gssapi_update_creds(ssh_gssapi_ccache *store) {
+       int ok = 0;
+
+       /* Check we've got credentials to store */
+       if (!gssapi_client.updated)
+               return 0;
+
+       gssapi_client.updated = 0;
+
+       temporarily_use_uid(gssapi_client.store.owner);
+       if (gssapi_client.mech && gssapi_client.mech->updatecreds)
+               ok = (*gssapi_client.mech->updatecreds)(store, &gssapi_client);
+       else
+               debug("No update function for this mechanism");
+
+       restore_uid();
+
+       return ok;
+}
+
 #endif
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