s4-kerberos Don't segfault if the password isn't specified in keytab generation
[samba.git] / source4 / auth / kerberos / kerberos_util.c
index d77a51916fae63f5fb95955654b8f1d6251018a4..76edf0d05aa8fed28e3e91f87c9eb4ad01f121a2 100644 (file)
 #include "auth/credentials/credentials_proto.h"
 #include "auth/credentials/credentials_krb5.h"
 #include "auth/kerberos/kerberos_credentials.h"
+#include "ldb.h"
+#include "param/secrets.h"
 
 struct principal_container {
        struct smb_krb5_context *smb_krb5_context;
        krb5_principal principal;
+       const char *string_form; /* Optional */
 };
 
 static krb5_error_code free_principal(struct principal_container *pc)
@@ -77,51 +80,185 @@ static krb5_error_code parse_principal(TALLOC_CTX *parent_ctx,
        return 0;
 }
 
-static krb5_error_code salt_principal_from_credentials(TALLOC_CTX *parent_ctx, 
-                                                      struct cli_credentials *machine_account, 
-                                                      struct smb_krb5_context *smb_krb5_context,
-                                                      krb5_principal *salt_princ)
+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 *machine_username;
-       char *salt_body;
-       char *lower_realm;
-       const char *salt_principal;
-       const char *error_string;
-       struct principal_container *mem_ctx = talloc(parent_ctx, struct principal_container);
-       if (!mem_ctx) {
+       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;
        }
 
-       salt_principal = cli_credentials_get_salt_principal(machine_account);
+       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 effectivly 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);
        if (salt_principal) {
-               ret = parse_principal(parent_ctx, salt_principal, smb_krb5_context, salt_princ, &error_string);
-       } else {
-               machine_username = talloc_strdup(mem_ctx, cli_credentials_get_username(machine_account));
+               return parse_principal(parent_ctx, salt_principal, smb_krb5_context, salt_princ, error_string);
+       } else if (samAccountName) {
+               krb5_error_code ret;
+               char *machine_username;
+               char *salt_body;
+               char *lower_realm;
+               char *upper_realm;
+
+               TALLOC_CTX *tmp_ctx;
+               struct principal_container *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(mem_ctx, cli_credentials_get_realm(machine_account));
+
+               lower_realm = strlower_talloc(tmp_ctx, realm);
                if (!lower_realm) {
                        talloc_free(mem_ctx);
+                       *error_string = "Cannot allocate to lower case realm";
                        return ENOMEM;
                }
                
-               salt_body = talloc_asprintf(mem_ctx, "%s.%s", machine_username, 
+               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);
-               return ENOMEM;
+                       *error_string = "Cannot form salt principal body";
+                       return ENOMEM;
                }
                
                ret = krb5_make_principal(smb_krb5_context->krb5_context, salt_princ, 
-                                         cli_credentials_get_realm(machine_account), 
+                                         upper_realm,
                                          "host", salt_body, NULL);
                if (ret == 0) {
                        /* This song-and-dance effectivly puts the principal
@@ -129,10 +266,15 @@ static krb5_error_code salt_principal_from_credentials(TALLOC_CTX *parent_ctx,
                        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);
                }
-       } 
-
-       return ret;
+               talloc_free(tmp_ctx);
+               return ret;
+       } else {
+               (*error_string) = "Cannot determine salt principal, no saltPrincipal or samAccountName specified";
+               return EINVAL;
+       }
 }
 
 /* Obtain the principal set on this context.  Requires a
@@ -140,7 +282,7 @@ static krb5_error_code salt_principal_from_credentials(TALLOC_CTX *parent_ctx,
  * the library routines.  The returned princ is placed in the talloc
  * system by means of a destructor (do *not* free). */
 
- krb5_error_code principal_from_credentials(TALLOC_CTX *parent_ctx, 
+krb5_error_code principal_from_credentials(TALLOC_CTX *parent_ctx, 
                                            struct cli_credentials *credentials, 
                                            struct smb_krb5_context *smb_krb5_context,
                                            krb5_principal *princ,
@@ -371,8 +513,9 @@ static krb5_error_code keytab_add_keys(TALLOC_CTX *parent_ctx,
                                       int kvno,
                                       const char *password_s,
                                       struct smb_krb5_context *smb_krb5_context,
-                                      const char **enctype_strings,
-                                      krb5_keytab keytab)
+                                      krb5_enctype *enctypes,
+                                      krb5_keytab keytab,
+                                      const char **error_string)
 {
        int i;
        krb5_error_code ret;
@@ -385,20 +528,10 @@ static krb5_error_code keytab_add_keys(TALLOC_CTX *parent_ctx,
        password.data = discard_const_p(char *, password_s);
        password.length = strlen(password_s);
 
-       for (i=0; enctype_strings[i]; i++) {
+       for (i=0; enctypes[i]; i++) {
                krb5_keytab_entry entry;
-               krb5_enctype enctype;
-               ret = krb5_string_to_enctype(smb_krb5_context->krb5_context, enctype_strings[i], &enctype);
-               if (ret != 0) {
-                       DEBUG(1, ("Failed to interpret %s as a krb5 encryption type: %s\n",                               
-                                 enctype_strings[i],
-                                 smb_get_krb5_error_message(smb_krb5_context->krb5_context, 
-                                                            ret, mem_ctx)));
-                       talloc_free(mem_ctx);
-                       return ret;
-               }
                ret = create_kerberos_key_from_string(smb_krb5_context->krb5_context, 
-                                                     salt_princ, &password, &entry.keyblock, enctype);
+                                                     salt_princ, &password, &entry.keyblock, enctypes[i]);
                if (ret != 0) {
                        talloc_free(mem_ctx);
                        return ret;
@@ -408,20 +541,20 @@ static krb5_error_code keytab_add_keys(TALLOC_CTX *parent_ctx,
                 entry.vno       = kvno;
                ret = krb5_kt_add_entry(smb_krb5_context->krb5_context, keytab, &entry);
                if (ret != 0) {
-                       DEBUG(1, ("Failed to add %s entry for %s(kvno %d) to keytab: %s\n",
-                                 enctype_strings[i],
-                                 princ_string,
-                                 kvno,
-                                 smb_get_krb5_error_message(smb_krb5_context->krb5_context, 
-                                                            ret, mem_ctx)));
+                       *error_string = talloc_asprintf(parent_ctx, "Failed to add enctype %d entry for %s(kvno %d) to keytab: %s\n",
+                                                       (int)enctypes[i],
+                                                       princ_string,
+                                                       kvno,
+                                                       smb_get_krb5_error_message(smb_krb5_context->krb5_context,
+                                                                                  ret, mem_ctx));
                        talloc_free(mem_ctx);
                        krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
                        return ret;
                }
 
-               DEBUG(5, ("Added %s(kvno %d) to keytab (%s)\n", 
+               DEBUG(5, ("Added %s(kvno %d) to keytab (enctype %d)\n", 
                          princ_string, kvno,
-                         enctype_strings[i]));
+                         (int)enctypes[i]));
                
                krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
        }
@@ -430,139 +563,91 @@ static krb5_error_code keytab_add_keys(TALLOC_CTX *parent_ctx,
 }
 
 static krb5_error_code create_keytab(TALLOC_CTX *parent_ctx,
-                        struct cli_credentials *machine_account,
-                        struct smb_krb5_context *smb_krb5_context,
-                        const char **enctype_strings,
-                        krb5_keytab keytab,
-                        bool add_old) 
+                                    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)
 {
+       unsigned int i;
        krb5_error_code ret;
        const char *password_s;
        const char *old_secret;
        int kvno;
+       uint32_t enctype_bitmap;
        krb5_principal salt_princ;
-       krb5_principal princ;
-       const char *princ_string;
-       const char *error_string;
-       enum credentials_obtained obtained;
-
+       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;
        }
 
-       princ_string = cli_credentials_get_principal(machine_account, mem_ctx);
-       /* Get the principal we will store the new keytab entries under */
-       ret = principal_from_credentials(mem_ctx, machine_account, smb_krb5_context, &princ, &obtained, &error_string);
-       if (ret) {
-               DEBUG(1,("create_keytab: makeing krb5 principal failed (%s)\n", error_string));
-               talloc_free(mem_ctx);
-               return ret;
-       }
-
        /* The salt used to generate these entries may be different however, fetch that */
-       ret = salt_principal_from_credentials(mem_ctx, machine_account, 
-                                             smb_krb5_context, 
-                                             &salt_princ);
+       ret = salt_principal_from_msg(mem_ctx, msg,
+                                     smb_krb5_context, 
+                                     &salt_princ, error_string);
        if (ret) {
-               DEBUG(1,("create_keytab: makeing salt principal failed (%s)\n",
-                        smb_get_krb5_error_message(smb_krb5_context->krb5_context, 
-                                                   ret, mem_ctx)));
                talloc_free(mem_ctx);
                return ret;
        }
 
-       /* Finally, do the dance to get the password to put in the entry */
-       password_s = cli_credentials_get_password(machine_account);
-       if (!password_s) {
-               krb5_keytab_entry entry;
-               const struct samr_Password *mach_pwd;
-
-               if (!str_list_check(enctype_strings, "arcfour-hmac-md5")) {
-                       DEBUG(1, ("Asked to create keytab, but with only an NT hash supplied, "
-                                 "but not listing arcfour-hmac-md5 as an enc type to include in the keytab!\n"));
-                       talloc_free(mem_ctx);
-                       return EINVAL;
-               }
-
-               /* If we don't have the plaintext password, try for
-                * the MD4 password hash */
-               mach_pwd = cli_credentials_get_nt_hash(machine_account, mem_ctx);
-               if (!mach_pwd) {
-                       /* OK, nothing to do here */
-                       talloc_free(mem_ctx);
-                       return 0;
-               }
-               ret = krb5_keyblock_init(smb_krb5_context->krb5_context,
-                                        ETYPE_ARCFOUR_HMAC_MD5,
-                                        mach_pwd->hash, sizeof(mach_pwd->hash), 
-                                        &entry.keyblock);
-               if (ret) {
-                       DEBUG(1, ("create_keytab: krb5_keyblock_init failed: %s\n",
-                                 smb_get_krb5_error_message(smb_krb5_context->krb5_context, 
-                                                            ret, mem_ctx)));
-                       talloc_free(mem_ctx);
-                       return ret;
-               }
-
-               entry.principal = princ;
-               entry.vno       = cli_credentials_get_kvno(machine_account);
-               ret = krb5_kt_add_entry(smb_krb5_context->krb5_context, keytab, &entry);
-               if (ret) {
-                       DEBUG(1, ("Failed to add ARCFOUR_HMAC (only) entry for %s to keytab: %s",
-                                 cli_credentials_get_principal(machine_account, mem_ctx), 
-                                 smb_get_krb5_error_message(smb_krb5_context->krb5_context, 
-                                                            ret, mem_ctx)));
-                       talloc_free(mem_ctx);
-                       krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
-                       return ret;
-               }
-               
-               DEBUG(5, ("Added %s(kvno %d) to keytab (arcfour-hmac-md5)\n", 
-                         cli_credentials_get_principal(machine_account, mem_ctx),
-                         cli_credentials_get_kvno(machine_account)));
+       kvno = ldb_msg_find_attr_as_int(msg, "msDS-KeyVersionNumber", 0);
 
-               krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
+       /* Finally, do the dance to get the password to put in the entry */
+       password_s =  ldb_msg_find_attr_as_string(msg, "secret", NULL);
 
-               /* Can't go any further, we only have this one key */
+       if (!password_s) {
+               /* There is no password here, so nothing to do */
                talloc_free(mem_ctx);
                return 0;
        }
-       
-       kvno = cli_credentials_get_kvno(machine_account);
-       /* good, we actually have the real plaintext */
-       ret = keytab_add_keys(mem_ctx, princ_string, princ, salt_princ, 
-                             kvno, password_s, smb_krb5_context, 
-                             enctype_strings, keytab);
-       if (!ret) {
-               talloc_free(mem_ctx);
-               return ret;
-       }
 
-       if (!add_old || kvno == 0) {
-               talloc_free(mem_ctx);
-               return 0;
+       if (add_old && kvno != 0) {
+               old_secret = ldb_msg_find_attr_as_string(msg, "priorSecret", NULL);
+       } else {
+               old_secret = NULL;
        }
 
-       old_secret = cli_credentials_get_old_password(machine_account);
-       if (!old_secret) {
-               talloc_free(mem_ctx);
-               return 0;
-       }
+       enctype_bitmap = (uint32_t)ldb_msg_find_attr_as_int(msg, "msDS-SupportedEncryptionTypes", ENC_ALL_TYPES);
        
-       ret = keytab_add_keys(mem_ctx, princ_string, princ, salt_princ, 
-                             kvno - 1, old_secret, smb_krb5_context, 
-                             enctype_strings, keytab);
-       if (!ret) {
+       ret = kerberos_enctype_bitmap_to_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;
        }
 
+       /* Walk over the principals */
+       for (i=0; principals[i]; i++) {
+               ret = keytab_add_keys(mem_ctx, principals[i]->string_form, principals[i]->principal,
+                                     salt_princ,
+                                     kvno, password_s, smb_krb5_context,
+                                     enctypes, keytab, error_string);
+               if (ret) {
+                       talloc_free(mem_ctx);
+                       return ret;
+               }
+
+               if (old_secret) {
+                       ret = keytab_add_keys(mem_ctx, principals[i]->string_form, principals[i]->principal,
+                                             salt_princ,
+                                             kvno - 1, old_secret, smb_krb5_context,
+                                             enctypes, keytab, error_string);
+                       if (ret) {
+                               talloc_free(mem_ctx);
+                               return ret;
+                       }
+               }
+       }
+
        talloc_free(mem_ctx);
-       return 0;
+       return ret;
 }
 
-
 /*
  * Walk the keytab, looking for entries of this principal name, with KVNO other than current kvno -1.
  *
@@ -573,35 +658,25 @@ static krb5_error_code create_keytab(TALLOC_CTX *parent_ctx,
  */
 
 static krb5_error_code remove_old_entries(TALLOC_CTX *parent_ctx,
-                                         struct cli_credentials *machine_account,
+                                         struct ldb_message *msg,
+                                         struct principal_container **principals,
+                                         bool delete_all_kvno,
                                          struct smb_krb5_context *smb_krb5_context,
-                                         krb5_keytab keytab, bool *found_previous)
+                                         krb5_keytab keytab, bool *found_previous,
+                                         const char **error_string)
 {
        krb5_error_code ret, ret2;
        krb5_kt_cursor cursor;
-       krb5_principal princ;
        int kvno;
        TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
-       const char *princ_string;
-       const char *error_string;
-       enum credentials_obtained obtained;
 
        if (!mem_ctx) {
                return ENOMEM;
        }
 
        *found_previous = false;
-       princ_string = cli_credentials_get_principal(machine_account, mem_ctx);
 
-       /* Get the principal we will store the new keytab entries under */
-       ret = principal_from_credentials(mem_ctx, machine_account, smb_krb5_context, &princ, &obtained, &error_string);
-       if (ret) {
-               DEBUG(1,("update_keytab: makeing krb5 principal failed (%s)\n", error_string));
-               talloc_free(mem_ctx);
-               return ret;
-       }
-
-       kvno = cli_credentials_get_kvno(machine_account);
+       kvno = ldb_msg_find_attr_as_int(msg, "msDS-KeyVersionNumber", 0);
 
        /* for each entry in the keytab */
        ret = krb5_kt_start_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
@@ -615,21 +690,30 @@ static krb5_error_code remove_old_entries(TALLOC_CTX *parent_ctx,
                talloc_free(mem_ctx);
                return 0;
        default:
-               DEBUG(1,("failed to open keytab for read of old entries: %s\n",
-                        smb_get_krb5_error_message(smb_krb5_context->krb5_context, 
-                                                   ret, mem_ctx)));
+               *error_string = talloc_asprintf(parent_ctx, "failed to open keytab for read of old entries: %s\n",
+                                               smb_get_krb5_error_message(smb_krb5_context->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(smb_krb5_context->krb5_context, keytab, &entry, &cursor);
                if (ret) {
                        break;
                }
-               /* if it matches our principal */
-               if (!krb5_kt_compare(smb_krb5_context->krb5_context, &entry, princ, 0, 0)) {
+               for (i = 0; principals[i]; i++) {
+                       /* if it matches our principal */
+                       if (krb5_kt_compare(smb_krb5_context->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(smb_krb5_context->krb5_context, &entry);
                        continue;
@@ -685,43 +769,73 @@ static krb5_error_code remove_old_entries(TALLOC_CTX *parent_ctx,
                ret = 0;
                break;
        default:
-               DEBUG(1,("failed in deleting old entries for principal: %s: %s\n",
-                        princ_string, 
-                        smb_get_krb5_error_message(smb_krb5_context->krb5_context, 
-                                                   ret, mem_ctx)));
+               *error_string = talloc_asprintf(parent_ctx, "failed in deleting old entries for principal: %s\n",
+                                               smb_get_krb5_error_message(smb_krb5_context->krb5_context,
+                                                                          ret, mem_ctx));
        }
        talloc_free(mem_ctx);
        return ret;
 }
 
 krb5_error_code smb_krb5_update_keytab(TALLOC_CTX *parent_ctx,
-                          struct cli_credentials *machine_account,
-                          struct smb_krb5_context *smb_krb5_context,
-                          const char **enctype_strings,
-                          struct keytab_container *keytab_container) 
+                                      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(parent_ctx);
+       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;
        }
 
-       ret = remove_old_entries(mem_ctx, machine_account, 
-                                smb_krb5_context, keytab_container->keytab, &found_previous);
+       keytab_name = keytab_name_from_msg(mem_ctx, ldb, msg);
+       if (!keytab_name) {
+               return ENOENT;
+       }
+
+       ret = smb_krb5_open_keytab(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, 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;
        }
        
-       /* 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, machine_account, smb_krb5_context, 
-                           enctype_strings, 
-                           keytab_container->keytab, 
-                           found_previous ? false : true);
+       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;
 }
@@ -729,13 +843,14 @@ krb5_error_code smb_krb5_update_keytab(TALLOC_CTX *parent_ctx,
 krb5_error_code smb_krb5_create_memory_keytab(TALLOC_CTX *parent_ctx,
                                           struct cli_credentials *machine_account,
                                           struct smb_krb5_context *smb_krb5_context,
-                                          const char **enctype_strings,
                                           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;
        }
@@ -760,16 +875,27 @@ krb5_error_code smb_krb5_create_memory_keytab(TALLOC_CTX *parent_ctx,
                return ret;
        }
 
-       ret = smb_krb5_update_keytab(mem_ctx, machine_account, smb_krb5_context, enctype_strings, *keytab_container);
+       msg = ldb_msg_new(mem_ctx);
+       if (!msg) {
+               talloc_free(mem_ctx);
+               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)
 {
@@ -812,7 +938,7 @@ krb5_enctype kerberos_enctype_bitmap_to_enctype(uint32_t enctype_bitmap)
 krb5_error_code kerberos_enctype_bitmap_to_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));
+       *enctypes = talloc_zero_array(mem_ctx, krb5_enctype, (8*sizeof(enctype_bitmap))+1);
        if (!*enctypes) {
                return ENOMEM;
        }
@@ -821,10 +947,11 @@ krb5_error_code kerberos_enctype_bitmap_to_enctypes(TALLOC_CTX *mem_ctx, uint32_
                if (bit_value & enctype_bitmap) {
                        (*enctypes)[j] = kerberos_enctype_bitmap_to_enctype(bit_value);
                        if (!(*enctypes)[j]) {
-                               return KRB5_PROG_ETYPE_NOSUPP;
+                               continue;
                        }
                        j++;
                }
        }
+       (*enctypes)[j] = 0;
        return 0;
 }