auth/kerberos: Use talloc_stackframe to avoid memory and FD leak of event context
[kai/samba-autobuild/.git] / source4 / auth / kerberos / kerberos_util.c
index c68efa96a8f4593bbf559d40459984656628ba14..c2e48fd51550e0e417e4403c2ae2f822b0f52177 100644 (file)
@@ -28,8 +28,6 @@
 #include "auth/credentials/credentials_krb5.h"
 #include "auth/kerberos/kerberos_credentials.h"
 #include "auth/kerberos/kerberos_util.h"
-#include <ldb.h>
-#include "param/secrets.h"
 
 struct principal_container {
        struct smb_krb5_context *smb_krb5_context;
@@ -84,235 +82,6 @@ static krb5_error_code parse_principal(TALLOC_CTX *parent_ctx,
        return 0;
 }
 
-static krb5_error_code principals_from_msg(TALLOC_CTX *parent_ctx,
-                       struct ldb_message *msg,
-                       struct smb_krb5_context *smb_krb5_context,
-                       struct principal_container ***principals_out,
-                       const char **error_string)
-{
-       unsigned int i;
-       krb5_error_code ret;
-       char *upper_realm;
-       const char *realm = ldb_msg_find_attr_as_string(msg, "realm", NULL);
-       const char *samAccountName = ldb_msg_find_attr_as_string(msg,
-                                               "samAccountName", NULL);
-       struct ldb_message_element *spn_el = ldb_msg_find_element(msg,
-                                               "servicePrincipalName");
-       TALLOC_CTX *tmp_ctx;
-       struct principal_container **principals;
-       tmp_ctx = talloc_new(parent_ctx);
-       if (!tmp_ctx) {
-               *error_string = "Cannot allocate tmp_ctx";
-               return ENOMEM;
-       }
-
-       if (!realm) {
-               *error_string = "Cannot have a kerberos secret in "
-                               "secrets.ldb without a realm";
-               return EINVAL;
-       }
-
-       upper_realm = strupper_talloc(tmp_ctx, realm);
-       if (!upper_realm) {
-               talloc_free(tmp_ctx);
-               *error_string = "Cannot allocate full upper case realm";
-               return ENOMEM;
-       }
-
-       principals = talloc_array(tmp_ctx, struct principal_container *,
-                                 spn_el ? (spn_el->num_values + 2) : 2);
-
-       spn_el = ldb_msg_find_element(msg, "servicePrincipalName");
-       for (i=0; spn_el && i < spn_el->num_values; i++) {
-               principals[i] = talloc(principals, struct principal_container);
-               if (!principals[i]) {
-                       talloc_free(tmp_ctx);
-                       *error_string = "Cannot allocate mem_ctx";
-                       return ENOMEM;
-               }
-
-               principals[i]->smb_krb5_context =
-                       talloc_reference(principals[i], smb_krb5_context);
-               principals[i]->string_form =
-                       talloc_asprintf(principals[i], "%*.*s@%s",
-                                       (int)spn_el->values[i].length,
-                                       (int)spn_el->values[i].length,
-                                       (const char *)spn_el->values[i].data,
-                                       upper_realm);
-               if (!principals[i]->string_form) {
-                       talloc_free(tmp_ctx);
-                       *error_string = "Cannot allocate full samAccountName";
-                       return ENOMEM;
-               }
-
-               ret = krb5_parse_name(smb_krb5_context->krb5_context,
-                                     principals[i]->string_form,
-                                     &principals[i]->principal);
-
-               if (ret) {
-                       talloc_free(tmp_ctx);
-                       (*error_string) = smb_get_krb5_error_message(
-                                               smb_krb5_context->krb5_context,
-                                               ret, parent_ctx);
-                       return ret;
-               }
-
-               /* This song-and-dance effectivly puts the principal
-                * into talloc, so we can't loose it. */
-               talloc_set_destructor(principals[i], free_principal);
-       }
-
-       if (samAccountName) {
-               principals[i] = talloc(principals, struct principal_container);
-               if (!principals[i]) {
-                       talloc_free(tmp_ctx);
-                       *error_string = "Cannot allocate mem_ctx";
-                       return ENOMEM;
-               }
-
-               principals[i]->smb_krb5_context =
-                       talloc_reference(principals[i], smb_krb5_context);
-               principals[i]->string_form =
-                       talloc_asprintf(parent_ctx, "%s@%s",
-                                       samAccountName, upper_realm);
-               if (!principals[i]->string_form) {
-                       talloc_free(tmp_ctx);
-                       *error_string = "Cannot allocate full samAccountName";
-                       return ENOMEM;
-               }
-
-               ret = krb5_make_principal(smb_krb5_context->krb5_context,
-                                         &principals[i]->principal,
-                                         upper_realm, samAccountName,
-                                         NULL);
-               if (ret) {
-                       talloc_free(tmp_ctx);
-                       (*error_string) = smb_get_krb5_error_message(
-                                               smb_krb5_context->krb5_context,
-                                               ret, parent_ctx);
-                       return ret;
-               }
-
-               /* This song-and-dance effectively puts the principal
-                * into talloc, so we can't loose it. */
-               talloc_set_destructor(principals[i], free_principal);
-               i++;
-       }
-
-       principals[i] = NULL;
-       *principals_out = talloc_steal(parent_ctx, principals);
-
-       talloc_free(tmp_ctx);
-       return ret;
-}
-
-static krb5_error_code salt_principal_from_msg(TALLOC_CTX *parent_ctx,
-                               struct ldb_message *msg,
-                               struct smb_krb5_context *smb_krb5_context,
-                               krb5_principal *salt_princ,
-                               const char **error_string)
-{
-       const char *salt_principal = ldb_msg_find_attr_as_string(msg,
-                                               "saltPrincipal", NULL);
-       const char *samAccountName = ldb_msg_find_attr_as_string(msg,
-                                               "samAccountName", NULL);
-       const char *realm = ldb_msg_find_attr_as_string(msg, "realm", NULL);
-
-       struct principal_container *mem_ctx;
-       krb5_error_code ret;
-       char *machine_username;
-       char *salt_body;
-       char *lower_realm;
-       char *upper_realm;
-
-       TALLOC_CTX *tmp_ctx;
-
-       if (salt_principal) {
-               return parse_principal(parent_ctx, salt_principal,
-                                       smb_krb5_context, salt_princ,
-                                       error_string);
-       }
-
-       if (!samAccountName) {
-               (*error_string) = "Cannot determine salt principal, no "
-                               "saltPrincipal or samAccountName specified";
-               return EINVAL;
-       }
-
-
-       mem_ctx = talloc(parent_ctx, struct principal_container);
-       if (!mem_ctx) {
-               *error_string = "Cannot allocate mem_ctx";
-               return ENOMEM;
-       }
-
-       tmp_ctx = talloc_new(mem_ctx);
-       if (!tmp_ctx) {
-               talloc_free(mem_ctx);
-               *error_string = "Cannot allocate tmp_ctx";
-               return ENOMEM;
-       }
-
-       if (!realm) {
-               *error_string = "Cannot have a kerberos secret in "
-                               "secrets.ldb without a realm";
-               return EINVAL;
-       }
-
-       machine_username = talloc_strdup(tmp_ctx, samAccountName);
-       if (!machine_username) {
-               talloc_free(mem_ctx);
-               *error_string = "Cannot duplicate samAccountName";
-               return ENOMEM;
-       }
-
-       if (machine_username[strlen(machine_username)-1] == '$') {
-               machine_username[strlen(machine_username)-1] = '\0';
-       }
-
-       lower_realm = strlower_talloc(tmp_ctx, realm);
-       if (!lower_realm) {
-               talloc_free(mem_ctx);
-               *error_string = "Cannot allocate to lower case realm";
-               return ENOMEM;
-       }
-
-       upper_realm = strupper_talloc(tmp_ctx, realm);
-       if (!upper_realm) {
-               talloc_free(mem_ctx);
-               *error_string = "Cannot allocate to upper case realm";
-               return ENOMEM;
-       }
-
-       salt_body = talloc_asprintf(tmp_ctx, "%s.%s", machine_username,
-                                   lower_realm);
-       talloc_free(lower_realm);
-       talloc_free(machine_username);
-       if (!salt_body) {
-               talloc_free(mem_ctx);
-               *error_string = "Cannot form salt principal body";
-               return ENOMEM;
-       }
-
-       ret = krb5_make_principal(smb_krb5_context->krb5_context, salt_princ,
-                                 upper_realm,
-                                 "host", salt_body, NULL);
-       if (ret == 0) {
-               /* This song-and-dance effectively puts the principal
-                * into talloc, so we can't loose it. */
-               mem_ctx->smb_krb5_context = talloc_reference(mem_ctx,
-                                                       smb_krb5_context);
-               mem_ctx->principal = *salt_princ;
-               talloc_set_destructor(mem_ctx, free_principal);
-       } else {
-               (*error_string) = smb_get_krb5_error_message(
-                                       smb_krb5_context->krb5_context,
-                                       ret, parent_ctx);
-       }
-       talloc_free(tmp_ctx);
-       return ret;
-}
-
 /* Obtain the principal set on this context.  Requires a
  * smb_krb5_context because we are doing krb5 principal parsing with
  * the library routines.  The returned princ is placed in the talloc
@@ -426,9 +195,10 @@ static krb5_error_code impersonate_principal_from_credentials(
                return ret;
        }
 
+#ifdef SAMBA4_USES_HEIMDAL /* Disable for now MIT reads defaults when needed */
        /* get the defaults */
        krb5_get_init_creds_opt_set_default_flags(smb_krb5_context->krb5_context, NULL, NULL, krb_options);
-
+#endif
        /* set if we want a forwardable ticket */
        switch (cli_credentials_get_krb_forwardable(credentials)) {
        case CRED_AUTO_KRB_FORWARDABLE:
@@ -441,18 +211,23 @@ static krb5_error_code impersonate_principal_from_credentials(
                break;
        }
 
+#ifdef SAMBA4_USES_HEIMDAL /* FIXME: MIT does not have this yet */
        /*
         * In order to work against windows KDCs even if we use
         * the netbios domain name as realm, we need to add the following
         * flags:
         * KRB5_INIT_CREDS_NO_C_CANON_CHECK;
         * KRB5_INIT_CREDS_NO_C_NO_EKU_CHECK;
+        *
+        * On MIT: Set pkinit_eku_checking to none
         */
        krb5_get_init_creds_opt_set_win2k(smb_krb5_context->krb5_context,
                                          krb_options, true);
+#endif
 
        tries = 2;
        while (tries--) {
+#ifdef SAMBA4_USES_HEIMDAL
                struct tevent_context *previous_ev;
                /* Do this every time, in case we have weird recursive issues here */
                ret = smb_krb5_context_set_event_ctx(smb_krb5_context, event_ctx, &previous_ev);
@@ -460,14 +235,29 @@ static krb5_error_code impersonate_principal_from_credentials(
                        talloc_free(mem_ctx);
                        return ret;
                }
+#endif
                if (password) {
-                       ret = kerberos_kinit_password_cc(smb_krb5_context->krb5_context, ccache, 
-                                                        princ, password,
-                                                        impersonate_principal,
-                                                        self_service,
-                                                        target_service,
-                                                        krb_options,
-                                                        NULL, &kdc_time);
+                       if (impersonate_principal) {
+#ifdef SAMBA4_USES_HEIMDAL
+                               ret = kerberos_kinit_s4u2_cc(
+                                               smb_krb5_context->krb5_context,
+                                               ccache, princ, password,
+                                               impersonate_principal,
+                                               self_service, target_service,
+                                               krb_options, NULL, &kdc_time);
+#else
+                               talloc_free(mem_ctx);
+                               (*error_string) = "INTERNAL error: s4u2 ops "
+                                       "are not supported with MIT build yet";
+                               return EINVAL;
+#endif
+                       } else {
+                               ret = kerberos_kinit_password_cc(
+                                               smb_krb5_context->krb5_context,
+                                               ccache, princ, password,
+                                               target_service,
+                                               krb_options, NULL, &kdc_time);
+                       }
                } else if (impersonate_principal) {
                        talloc_free(mem_ctx);
                        (*error_string) = "INTERNAL error: Cannot impersonate principal with just a keyblock.  A password must be specified in the credentials";
@@ -482,10 +272,12 @@ static krb5_error_code impersonate_principal_from_credentials(
                                talloc_free(mem_ctx);
                                (*error_string) = "kinit_to_ccache: No password available for kinit\n";
                                krb5_get_init_creds_opt_free(smb_krb5_context->krb5_context, krb_options);
+#ifdef SAMBA4_USES_HEIMDAL
                                smb_krb5_context_remove_event_ctx(smb_krb5_context, previous_ev, event_ctx);
+#endif
                                return EINVAL;
                        }
-                       ret = krb5_keyblock_init(smb_krb5_context->krb5_context,
+                       ret = smb_krb5_keyblock_init_contents(smb_krb5_context->krb5_context,
                                                 ENCTYPE_ARCFOUR_HMAC,
                                                 mach_pwd->hash, sizeof(mach_pwd->hash), 
                                                 &keyblock);
@@ -499,7 +291,9 @@ static krb5_error_code impersonate_principal_from_credentials(
                        }
                }
 
+#ifdef SAMBA4_USES_HEIMDAL
                smb_krb5_context_remove_event_ctx(smb_krb5_context, previous_ev, event_ctx);
+#endif
 
                if (ret == KRB5KRB_AP_ERR_SKEW || ret == KRB5_KDCREP_SKEW) {
                        /* Perhaps we have been given an invalid skew, so try again without it */
@@ -557,507 +351,37 @@ static krb5_error_code free_keytab_container(struct keytab_container *ktc)
 }
 
 krb5_error_code smb_krb5_get_keytab_container(TALLOC_CTX *mem_ctx,
-                                             struct smb_krb5_context *smb_krb5_context,
-                                             const char *keytab_name, struct keytab_container **ktc)
+                               struct smb_krb5_context *smb_krb5_context,
+                               krb5_keytab opt_keytab,
+                               const char *keytab_name,
+                               struct keytab_container **ktc)
 {
        krb5_keytab keytab;
        krb5_error_code ret;
-       ret = krb5_kt_resolve(smb_krb5_context->krb5_context, keytab_name, &keytab);
-       if (ret) {
-               DEBUG(1,("failed to open krb5 keytab: %s\n", 
-                        smb_get_krb5_error_message(smb_krb5_context->krb5_context, 
-                                                   ret, mem_ctx)));
-               return ret;
-       }
-
-       *ktc = talloc(mem_ctx, struct keytab_container);
-       if (!*ktc) {
-               return ENOMEM;
-       }
-
-       (*ktc)->smb_krb5_context = talloc_reference(*ktc, smb_krb5_context);
-       (*ktc)->keytab = keytab;
-       talloc_set_destructor(*ktc, free_keytab_container);
-
-       return 0;
-}
-
-static krb5_error_code keytab_add_keys(TALLOC_CTX *parent_ctx,
-                                      struct principal_container **principals,
-                                      krb5_principal salt_princ,
-                                      int kvno,
-                                      const char *password_s,
-                                      krb5_context krb5_context,
-                                      krb5_enctype *enctypes,
-                                      krb5_keytab keytab,
-                                      const char **error_string)
-{
-       unsigned int i, p;
-       krb5_error_code ret;
-       krb5_data password;
-
-       password.data = discard_const_p(char *, password_s);
-       password.length = strlen(password_s);
-
-       for (i = 0; enctypes[i]; i++) {
-               krb5_keytab_entry entry;
-
-               ZERO_STRUCT(entry);
-
-               ret = create_kerberos_key_from_string_direct(krb5_context,
-                                               salt_princ, &password,
-                                               &entry.keyblock, enctypes[i]);
-               if (ret != 0) {
-                       return ret;
-               }
-
-                entry.vno = kvno;
-
-               for (p = 0; principals[p]; p++) {
-                       entry.principal = principals[p]->principal;
-                       ret = krb5_kt_add_entry(krb5_context,
-                                               keytab, &entry);
-                       if (ret != 0) {
-                               char *k5_error_string =
-                                       smb_get_krb5_error_message(
-                                               krb5_context, ret, NULL);
-                               *error_string = talloc_asprintf(parent_ctx,
-                                       "Failed to add enctype %d entry for "
-                                       "%s(kvno %d) to keytab: %s\n",
-                                       (int)enctypes[i],
-                                       principals[p]->string_form,
-                                       kvno, k5_error_string);
-
-                               talloc_free(k5_error_string);
-                               krb5_free_keyblock_contents(krb5_context,
-                                                           &entry.keyblock);
-                               return ret;
-                       }
-
-                       DEBUG(5, ("Added %s(kvno %d) to keytab (enctype %d)\n", 
-                                 principals[p]->string_form, kvno,
-                                 (int)enctypes[i]));
-               }
-               krb5_free_keyblock_contents(krb5_context, &entry.keyblock);
-       }
-       return 0;
-}
-
-static krb5_error_code ms_suptypes_to_ietf_enctypes(TALLOC_CTX *mem_ctx,
-                                               uint32_t enctype_bitmap,
-                                               krb5_enctype **enctypes);
-
-static krb5_error_code create_keytab(TALLOC_CTX *parent_ctx,
-                                    struct ldb_message *msg,
-                                    struct principal_container **principals,
-                                    struct smb_krb5_context *smb_krb5_context,
-                                    krb5_keytab keytab,
-                                    bool add_old,
-                                    const char **error_string)
-{
-       krb5_error_code ret;
-       const char *password_s;
-       const char *old_secret;
-       int kvno;
-       uint32_t enctype_bitmap;
-       krb5_principal salt_princ;
-       krb5_enctype *enctypes;
-       TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
-       if (!mem_ctx) {
-               *error_string = "unable to allocate tmp_ctx for create_keytab";
-               return ENOMEM;
-       }
-
-       /* The salt used to generate these entries may be different however,
-        * fetch that */
-       ret = salt_principal_from_msg(mem_ctx, msg,
-                                     smb_krb5_context,
-                                     &salt_princ, error_string);
-       if (ret) {
-               talloc_free(mem_ctx);
-               return ret;
-       }
-
-       kvno = ldb_msg_find_attr_as_int(msg, "msDS-KeyVersionNumber", 0);
-
-       /* Finally, do the dance to get the password to put in the entry */
-       password_s =  ldb_msg_find_attr_as_string(msg, "secret", NULL);
-
-       if (!password_s) {
-               /* There is no password here, so nothing to do */
-               talloc_free(mem_ctx);
-               return 0;
-       }
 
-       if (add_old && kvno != 0) {
-               old_secret = ldb_msg_find_attr_as_string(msg,
-                                                       "priorSecret", NULL);
+       if (opt_keytab) {
+               keytab = opt_keytab;
        } else {
-               old_secret = NULL;
-       }
-
-       enctype_bitmap = (uint32_t)ldb_msg_find_attr_as_int(msg,
-                                       "msDS-SupportedEncryptionTypes",
-                                       ENC_ALL_TYPES);
-
-       ret = ms_suptypes_to_ietf_enctypes(mem_ctx, enctype_bitmap, &enctypes);
-       if (ret) {
-               *error_string = talloc_asprintf(parent_ctx,
-                                       "create_keytab: generating list of "
-                                       "encryption types failed (%s)\n",
-                                       smb_get_krb5_error_message(
-                                               smb_krb5_context->krb5_context,
-                                               ret, mem_ctx));
-               talloc_free(mem_ctx);
-               return ret;
-       }
-
-       ret = keytab_add_keys(mem_ctx, principals,
-                             salt_princ, kvno, password_s,
-                             smb_krb5_context->krb5_context,
-                             enctypes, keytab, error_string);
-       if (ret) {
-               talloc_free(mem_ctx);
-               return ret;
-       }
-
-       if (old_secret) {
-               ret = keytab_add_keys(mem_ctx, principals,
-                                     salt_princ, kvno - 1, old_secret,
-                                     smb_krb5_context->krb5_context,
-                                     enctypes, keytab, error_string);
+               ret = krb5_kt_resolve(smb_krb5_context->krb5_context,
+                                               keytab_name, &keytab);
                if (ret) {
-                       talloc_free(mem_ctx);
+                       DEBUG(1,("failed to open krb5 keytab: %s\n",
+                                smb_get_krb5_error_message(
+                                       smb_krb5_context->krb5_context,
+                                       ret, mem_ctx)));
                        return ret;
                }
        }
 
-       talloc_free(mem_ctx);
-       return ret;
-}
-
-/*
- * Walk the keytab, looking for entries of this principal name,
- * with KVNO other than current kvno -1.
- *
- * These entries are now stale,
- * we only keep the current and previous entries around.
- *
- * Inspired by the code in Samba3 for 'use kerberos keytab'.
- */
-
-static krb5_error_code remove_old_entries(TALLOC_CTX *parent_ctx,
-                                         struct ldb_message *msg,
-                                         struct principal_container **principals,
-                                         bool delete_all_kvno,
-                                         krb5_context krb5_context,
-                                         krb5_keytab keytab,
-                                         bool *found_previous,
-                                         const char **error_string)
-{
-       krb5_error_code ret, ret2;
-       krb5_kt_cursor cursor;
-       int kvno;
-       TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
-
-       if (!mem_ctx) {
-               return ENOMEM;
-       }
-
-       *found_previous = false;
-
-       kvno = ldb_msg_find_attr_as_int(msg, "msDS-KeyVersionNumber", 0);
-
-       /* for each entry in the keytab */
-       ret = krb5_kt_start_seq_get(krb5_context, keytab, &cursor);
-       switch (ret) {
-       case 0:
-               break;
-       case HEIM_ERR_OPNOTSUPP:
-       case ENOENT:
-       case KRB5_KT_END:
-               /* no point enumerating if there isn't anything here */
-               talloc_free(mem_ctx);
-               return 0;
-       default:
-               *error_string = talloc_asprintf(parent_ctx,
-                       "failed to open keytab for read of old entries: %s\n",
-                       smb_get_krb5_error_message(krb5_context,
-                                                  ret, mem_ctx));
-               talloc_free(mem_ctx);
-               return ret;
-       }
-
-       while (!ret) {
-               unsigned int i;
-               bool matched = false;
-               krb5_keytab_entry entry;
-               ret = krb5_kt_next_entry(krb5_context, keytab,
-                                        &entry, &cursor);
-               if (ret) {
-                       break;
-               }
-               for (i = 0; principals[i]; i++) {
-                       /* if it matches our principal */
-                       if (krb5_kt_compare(krb5_context, &entry,
-                                           principals[i]->principal, 0, 0)) {
-                               matched = true;
-                               break;
-                       }
-               }
-
-               if (!matched) {
-                       /* Free the entry,
-                        * it wasn't the one we were looking for anyway */
-                       krb5_kt_free_entry(krb5_context, &entry);
-                       continue;
-               }
-
-               /* delete it, if it is not kvno -1 */
-               if (entry.vno != (kvno - 1 )) {
-                       /* Release the enumeration.  We are going to
-                        * have to start this from the top again,
-                        * because deletes during enumeration may not
-                        * always be consistent.
-                        *
-                        * Also, the enumeration locks a FILE: keytab
-                        */
-
-                       krb5_kt_end_seq_get(krb5_context, keytab, &cursor);
-
-                       ret = krb5_kt_remove_entry(krb5_context, keytab, &entry);
-                       krb5_kt_free_entry(krb5_context, &entry);
-
-                       /* Deleted: Restart from the top */
-                       ret2 = krb5_kt_start_seq_get(krb5_context,
-                                                    keytab, &cursor);
-                       if (ret2) {
-                               krb5_kt_free_entry(krb5_context, &entry);
-                               DEBUG(1, ("failed to restart enumeration of keytab: %s\n",
-                                         smb_get_krb5_error_message(krb5_context,
-                                                                   ret, mem_ctx)));
-
-                               talloc_free(mem_ctx);
-                               return ret2;
-                       }
-
-                       if (ret) {
-                               break;
-                       }
-
-               } else {
-                       *found_previous = true;
-               }
-
-               /* Free the entry, we don't need it any more */
-               krb5_kt_free_entry(krb5_context, &entry);
-       }
-       krb5_kt_end_seq_get(krb5_context, keytab, &cursor);
-
-       switch (ret) {
-       case 0:
-               break;
-       case ENOENT:
-       case KRB5_KT_END:
-               ret = 0;
-               break;
-       default:
-               *error_string = talloc_asprintf(parent_ctx,
-                       "failed in deleting old entries for principal: %s\n",
-                       smb_get_krb5_error_message(krb5_context,
-                                                  ret, mem_ctx));
-       }
-       talloc_free(mem_ctx);
-       return ret;
-}
-
-krb5_error_code smb_krb5_update_keytab(TALLOC_CTX *parent_ctx,
-                                      struct smb_krb5_context *smb_krb5_context,
-                                      struct ldb_context *ldb,
-                                      struct ldb_message *msg,
-                                      bool delete_all_kvno,
-                                      const char **error_string)
-{
-       krb5_error_code ret;
-       bool found_previous;
-       TALLOC_CTX *mem_ctx = talloc_new(NULL);
-       struct keytab_container *keytab_container;
-       struct principal_container **principals;
-       const char *keytab_name;
-
-       if (!mem_ctx) {
-               return ENOMEM;
-       }
-
-       keytab_name = keytab_name_from_msg(mem_ctx, ldb, msg);
-       if (!keytab_name) {
-               return ENOENT;
-       }
-
-       ret = smb_krb5_get_keytab_container(mem_ctx, smb_krb5_context,
-                                       keytab_name, &keytab_container);
-
-       if (ret != 0) {
-               talloc_free(mem_ctx);
-               return ret;
-       }
-
-       DEBUG(5, ("Opened keytab %s\n", keytab_name));
-
-       /* Get the principal we will store the new keytab entries under */
-       ret = principals_from_msg(mem_ctx, msg, smb_krb5_context,
-                                       &principals, error_string);
-
-       if (ret != 0) {
-               *error_string = talloc_asprintf(parent_ctx,
-                       "Failed to load principals from ldb message: %s\n",
-                       *error_string);
-               talloc_free(mem_ctx);
-               return ret;
-       }
-
-       ret = remove_old_entries(mem_ctx, msg, principals, delete_all_kvno,
-                                smb_krb5_context->krb5_context,
-                                keytab_container->keytab,
-                                &found_previous, error_string);
-       if (ret != 0) {
-               *error_string = talloc_asprintf(parent_ctx,
-                       "Failed to remove old principals from keytab: %s\n",
-                       *error_string);
-               talloc_free(mem_ctx);
-               return ret;
-       }
-
-       if (!delete_all_kvno) {
-               /* Create a new keytab.  If during the cleanout we found
-                * entires for kvno -1, then don't try and duplicate them.
-                * Otherwise, add kvno, and kvno -1 */
-
-               ret = create_keytab(mem_ctx, msg, principals,
-                                   smb_krb5_context,
-                                   keytab_container->keytab,
-                                   found_previous ? false : true,
-                                   error_string);
-       }
-       talloc_free(mem_ctx);
-       return ret;
-}
-
-krb5_error_code smb_krb5_create_memory_keytab(TALLOC_CTX *parent_ctx,
-                                          struct cli_credentials *machine_account,
-                                          struct smb_krb5_context *smb_krb5_context,
-                                          struct keytab_container **keytab_container) 
-{
-       krb5_error_code ret;
-       TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
-       const char *rand_string;
-       const char *keytab_name;
-       struct ldb_message *msg;
-       const char *error_string;
-       if (!mem_ctx) {
-               return ENOMEM;
-       }
-       
-       *keytab_container = talloc(mem_ctx, struct keytab_container);
-
-       rand_string = generate_random_str(mem_ctx, 16);
-       if (!rand_string) {
-               talloc_free(mem_ctx);
-               return ENOMEM;
-       }
-
-       keytab_name = talloc_asprintf(mem_ctx, "MEMORY:%s", 
-                                     rand_string);
-       if (!keytab_name) {
-               talloc_free(mem_ctx);
-               return ENOMEM;
-       }
-
-       ret = smb_krb5_get_keytab_container(mem_ctx, smb_krb5_context, keytab_name, keytab_container);
-       if (ret) {
-               return ret;
-       }
-
-       msg = ldb_msg_new(mem_ctx);
-       if (!msg) {
-               talloc_free(mem_ctx);
+       *ktc = talloc(mem_ctx, struct keytab_container);
+       if (!*ktc) {
                return ENOMEM;
        }
-       ldb_msg_add_string(msg, "krb5Keytab", keytab_name);
-       ldb_msg_add_string(msg, "secret", cli_credentials_get_password(machine_account));
-       ldb_msg_add_string(msg, "samAccountName", cli_credentials_get_username(machine_account));
-       ldb_msg_add_string(msg, "realm", cli_credentials_get_realm(machine_account));
-       ldb_msg_add_fmt(msg, "msDS-KeyVersionNumber", "%d", (int)cli_credentials_get_kvno(machine_account));
 
-       ret = smb_krb5_update_keytab(mem_ctx, smb_krb5_context, NULL, msg, false, &error_string);
-       if (ret == 0) {
-               talloc_steal(parent_ctx, *keytab_container);
-       } else {
-               DEBUG(0, ("Failed to create in-memory keytab: %s\n", error_string));
-               *keytab_container = NULL;
-       }
-       talloc_free(mem_ctx);
-       return ret;
-}
-/* Translate between the IETF encryption type values and the Microsoft msDS-SupportedEncryptionTypes values */
-uint32_t kerberos_enctype_to_bitmap(krb5_enctype enc_type_enum)
-{
-       switch (enc_type_enum) {
-       case ENCTYPE_DES_CBC_CRC:
-               return ENC_CRC32;
-       case ENCTYPE_DES_CBC_MD5:
-               return ENC_RSA_MD5;
-       case ENCTYPE_ARCFOUR_HMAC_MD5:
-               return ENC_RC4_HMAC_MD5;
-       case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
-               return ENC_HMAC_SHA1_96_AES128;
-       case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
-               return ENC_HMAC_SHA1_96_AES256;
-       default:
-               return 0;
-       }
-}
+       (*ktc)->smb_krb5_context = talloc_reference(*ktc, smb_krb5_context);
+       (*ktc)->keytab = keytab;
+       (*ktc)->password_based = false;
+       talloc_set_destructor(*ktc, free_keytab_container);
 
-/* Translate between the Microsoft msDS-SupportedEncryptionTypes values
- * and the IETF encryption type values */
-static krb5_enctype ms_suptype_to_ietf_enctype(uint32_t enctype_bitmap)
-{
-       switch (enctype_bitmap) {
-       case ENC_CRC32:
-               return ENCTYPE_DES_CBC_CRC;
-       case ENC_RSA_MD5:
-               return ENCTYPE_DES_CBC_MD5;
-       case ENC_RC4_HMAC_MD5:
-               return ENCTYPE_ARCFOUR_HMAC_MD5;
-       case ENC_HMAC_SHA1_96_AES128:
-               return ENCTYPE_AES128_CTS_HMAC_SHA1_96;
-       case ENC_HMAC_SHA1_96_AES256:
-               return ENCTYPE_AES256_CTS_HMAC_SHA1_96;
-       default:
-               return 0;
-       }
-}
-/* Return an array of krb5_enctype values */
-static krb5_error_code ms_suptypes_to_ietf_enctypes(TALLOC_CTX *mem_ctx,
-                                               uint32_t enctype_bitmap,
-                                               krb5_enctype **enctypes)
-{
-       unsigned int i, j = 0;
-       *enctypes = talloc_zero_array(mem_ctx, krb5_enctype,
-                                       (8 * sizeof(enctype_bitmap)) + 1);
-       if (!*enctypes) {
-               return ENOMEM;
-       }
-       for (i = 0; i < (8 * sizeof(enctype_bitmap)); i++) {
-               uint32_t bit_value = (1 << i) & enctype_bitmap;
-               if (bit_value & enctype_bitmap) {
-                       (*enctypes)[j] = ms_suptype_to_ietf_enctype(bit_value);
-                       if (!(*enctypes)[j]) {
-                               continue;
-                       }
-                       j++;
-               }
-       }
-       (*enctypes)[j] = 0;
        return 0;
 }