/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
/* dbus-credentials.c Credentials provable through authentication
 *
 * Copyright (C) 2007 Red Hat Inc.
 *
 * Licensed under the Academic Free License version 2.1
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
 *
 */
#include "dbus-credentials.h"

#include <config.h>
#include <string.h>

#include "dbus-internals.h"

/**
 * @defgroup DBusCredentials Credentials provable through authentication
 * @ingroup  DBusInternals
 * @brief DBusCredentials object
 *
 * Credentials are what you have to prove you have in order to
 * authenticate.  The main credentials right now are a unix user
 * account, a Windows user account, or a UNIX process ID.
 */

/**
 * @defgroup DBusCredentialsInternals Credentials implementation details
 * @ingroup  DBusInternals
 * @brief DBusCredentials implementation details
 *
 * Private details of credentials code.
 *
 * @{
 */

struct DBusCredentials
{
    int refcount;
    dbus_uid_t unix_uid;
    dbus_pid_t pid;
    char* windows_sid;
    char* linux_security_label;
    void* adt_audit_data;
    dbus_int32_t adt_audit_data_size;
};

/** @} */

/**
 * @addtogroup DBusCredentials
 * @{
 */

/**
 * Creates a new credentials object.
 *
 * @returns the new object or #NULL if no memory
 */
DBusCredentials* _dbus_credentials_new(void)
{
    DBusCredentials* creds;

    creds = dbus_new(DBusCredentials, 1);
    if (creds == NULL)
        return NULL;

    creds->refcount = 1;
    creds->unix_uid = DBUS_UID_UNSET;
    creds->pid = DBUS_PID_UNSET;
    creds->windows_sid = NULL;
    creds->linux_security_label = NULL;
    creds->adt_audit_data = NULL;
    creds->adt_audit_data_size = 0;

    return creds;
}

/**
 * Creates a new object with credentials (user ID and process ID) from the
 * current process.
 * @returns the new object or #NULL if no memory
 */
DBusCredentials* _dbus_credentials_new_from_current_process(void)
{
    DBusCredentials* creds;

    creds = _dbus_credentials_new();
    if (creds == NULL)
        return NULL;

    if (!_dbus_credentials_add_from_current_process(creds))
    {
        _dbus_credentials_unref(creds);
        return NULL;
    }

    return creds;
}

/**
 * Increment refcount on credentials.
 *
 * @param credentials the object
 */
void _dbus_credentials_ref(DBusCredentials* credentials)
{
    _dbus_assert(credentials->refcount > 0);
    credentials->refcount += 1;
}

/**
 * Decrement refcount on credentials.
 *
 * @param credentials the object
 */
void _dbus_credentials_unref(DBusCredentials* credentials)
{
    _dbus_assert(credentials->refcount > 0);

    credentials->refcount -= 1;
    if (credentials->refcount == 0)
    {
        dbus_free(credentials->windows_sid);
        dbus_free(credentials->linux_security_label);
        dbus_free(credentials->adt_audit_data);
        dbus_free(credentials);
    }
}

/**
 * Add a UNIX process ID to the credentials.
 *
 * @param credentials the object
 * @param pid the process ID
 * @returns #FALSE if no memory
 */
dbus_bool_t _dbus_credentials_add_pid(DBusCredentials* credentials,
                                      dbus_pid_t pid)
{
    credentials->pid = pid;
    return TRUE;
}

/**
 * Add a UNIX user ID to the credentials.
 *
 * @param credentials the object
 * @param uid the user ID
 * @returns #FALSE if no memory
 */
dbus_bool_t _dbus_credentials_add_unix_uid(DBusCredentials* credentials,
                                           dbus_uid_t uid)
{
    credentials->unix_uid = uid;
    return TRUE;
}

/**
 * Add a Windows user SID to the credentials.
 *
 * @param credentials the object
 * @param windows_sid the user SID
 * @returns #FALSE if no memory
 */
dbus_bool_t _dbus_credentials_add_windows_sid(DBusCredentials* credentials,
                                              const char* windows_sid)
{
    char* copy;

    copy = _dbus_strdup(windows_sid);
    if (copy == NULL)
        return FALSE;

    dbus_free(credentials->windows_sid);
    credentials->windows_sid = copy;

    return TRUE;
}

/**
 * Add a Linux security label, as used by LSMs such as SELinux, Smack and
 * AppArmor, to the credentials.
 *
 * @param credentials the object
 * @param label the label
 * @returns #FALSE if no memory
 */
dbus_bool_t
    _dbus_credentials_add_linux_security_label(DBusCredentials* credentials,
                                               const char* label)
{
    char* copy;

    copy = _dbus_strdup(label);
    if (copy == NULL)
        return FALSE;

    dbus_free(credentials->linux_security_label);
    credentials->linux_security_label = copy;

    return TRUE;
}

/**
 * Add ADT audit data to the credentials.
 *
 * @param credentials the object
 * @param audit_data the audit data
 * @param size the length of audit data
 * @returns #FALSE if no memory
 */
dbus_bool_t _dbus_credentials_add_adt_audit_data(DBusCredentials* credentials,
                                                 void* audit_data,
                                                 dbus_int32_t size)
{
    void* copy;
    copy = _dbus_memdup(audit_data, size);
    if (copy == NULL)
        return FALSE;

    dbus_free(credentials->adt_audit_data);
    credentials->adt_audit_data = copy;
    credentials->adt_audit_data_size = size;

    return TRUE;
}

/**
 * Checks whether the given credential is present.
 *
 * @param credentials the object
 * @param type the credential to check for
 * @returns #TRUE if the credential is present
 */
dbus_bool_t _dbus_credentials_include(DBusCredentials* credentials,
                                      DBusCredentialType type)
{
    switch (type)
    {
        case DBUS_CREDENTIAL_UNIX_PROCESS_ID:
            return credentials->pid != DBUS_PID_UNSET;
        case DBUS_CREDENTIAL_UNIX_USER_ID:
            return credentials->unix_uid != DBUS_UID_UNSET;
        case DBUS_CREDENTIAL_WINDOWS_SID:
            return credentials->windows_sid != NULL;
        case DBUS_CREDENTIAL_LINUX_SECURITY_LABEL:
            return credentials->linux_security_label != NULL;
        case DBUS_CREDENTIAL_ADT_AUDIT_DATA_ID:
            return credentials->adt_audit_data != NULL;
        default:
            _dbus_assert_not_reached("Unknown credential enum value");
            return FALSE;
    }
}

/**
 * Gets the UNIX process ID in the credentials, or #DBUS_PID_UNSET if
 * the credentials object doesn't contain a process ID.
 *
 * @param credentials the object
 * @returns UNIX process ID
 */
dbus_pid_t _dbus_credentials_get_pid(DBusCredentials* credentials)
{
    return credentials->pid;
}

/**
 * Gets the UNIX user ID in the credentials, or #DBUS_UID_UNSET if
 * the credentials object doesn't contain a user ID.
 *
 * @param credentials the object
 * @returns UNIX user ID
 */
dbus_uid_t _dbus_credentials_get_unix_uid(DBusCredentials* credentials)
{
    return credentials->unix_uid;
}

/**
 * Gets the Windows user SID in the credentials, or #NULL if
 * the credentials object doesn't contain a Windows user SID.
 *
 * @param credentials the object
 * @returns Windows user SID
 */
const char* _dbus_credentials_get_windows_sid(DBusCredentials* credentials)
{
    return credentials->windows_sid;
}

/**
 * Gets the Linux security label (as used by LSMs) from the credentials,
 * or #NULL if the credentials object doesn't contain a security label.
 *
 * @param credentials the object
 * @returns the security label
 */
const char*
    _dbus_credentials_get_linux_security_label(DBusCredentials* credentials)
{
    return credentials->linux_security_label;
}

/**
 * Gets the ADT audit data in the credentials, or #NULL if
 * the credentials object doesn't contain ADT audit data.
 *
 * @param credentials the object
 * @returns Solaris ADT audit data
 */
void* _dbus_credentials_get_adt_audit_data(DBusCredentials* credentials)
{
    return credentials->adt_audit_data;
}

/**
 * Gets the ADT audit data size in the credentials, or 0 if
 * the credentials object doesn't contain ADT audit data.
 *
 * @param credentials the object
 * @returns Solaris ADT audit data size
 */
dbus_int32_t
    _dbus_credentials_get_adt_audit_data_size(DBusCredentials* credentials)
{
    return credentials->adt_audit_data_size;
}

/**
 * Checks whether the first credentials object contains
 * all the credentials found in the second credentials object.
 *
 * @param credentials the object
 * @param possible_subset see if credentials in here are also in the first arg
 * @returns #TRUE if second arg is contained in first
 */
dbus_bool_t _dbus_credentials_are_superset(DBusCredentials* credentials,
                                           DBusCredentials* possible_subset)
{
    return (possible_subset->pid == DBUS_PID_UNSET ||
            possible_subset->pid == credentials->pid) &&
           (possible_subset->unix_uid == DBUS_UID_UNSET ||
            possible_subset->unix_uid == credentials->unix_uid) &&
           (possible_subset->windows_sid == NULL ||
            (credentials->windows_sid &&
             strcmp(possible_subset->windows_sid, credentials->windows_sid) ==
                 0)) &&
           (possible_subset->linux_security_label == NULL ||
            (credentials->linux_security_label != NULL &&
             strcmp(possible_subset->linux_security_label,
                    credentials->linux_security_label) == 0)) &&
           (possible_subset->adt_audit_data == NULL ||
            (credentials->adt_audit_data &&
             memcmp(possible_subset->adt_audit_data,
                    credentials->adt_audit_data,
                    credentials->adt_audit_data_size) == 0));
}

/**
 * Checks whether a credentials object contains anything.
 *
 * @param credentials the object
 * @returns #TRUE if there are no credentials in the object
 */
dbus_bool_t _dbus_credentials_are_empty(DBusCredentials* credentials)
{
    return credentials->pid == DBUS_PID_UNSET &&
           credentials->unix_uid == DBUS_UID_UNSET &&
           credentials->windows_sid == NULL &&
           credentials->linux_security_label == NULL &&
           credentials->adt_audit_data == NULL;
}

/**
 * Checks whether a credentials object contains a user identity.
 *
 * @param credentials the object
 * @returns #TRUE if there are no user identities in the object
 */
dbus_bool_t _dbus_credentials_are_anonymous(DBusCredentials* credentials)
{
    return credentials->unix_uid == DBUS_UID_UNSET &&
           credentials->windows_sid == NULL;
}

/**
 * Merge all credentials found in the second object into the first object,
 * overwriting the first object if there are any overlaps.
 *
 * @param credentials the object
 * @param other_credentials credentials to merge
 * @returns #FALSE if no memory
 */
dbus_bool_t
    _dbus_credentials_add_credentials(DBusCredentials* credentials,
                                      DBusCredentials* other_credentials)
{
    return _dbus_credentials_add_credential(credentials,
                                            DBUS_CREDENTIAL_UNIX_PROCESS_ID,
                                            other_credentials) &&
           _dbus_credentials_add_credential(
               credentials, DBUS_CREDENTIAL_UNIX_USER_ID, other_credentials) &&
           _dbus_credentials_add_credential(credentials,
                                            DBUS_CREDENTIAL_ADT_AUDIT_DATA_ID,
                                            other_credentials) &&
           _dbus_credentials_add_credential(
               credentials, DBUS_CREDENTIAL_LINUX_SECURITY_LABEL,
               other_credentials) &&
           _dbus_credentials_add_credential(
               credentials, DBUS_CREDENTIAL_WINDOWS_SID, other_credentials);
}

/**
 * Merge the given credential found in the second object into the first object,
 * overwriting the first object's value for that credential.
 *
 * Does nothing if the second object does not contain the specified credential.
 * i.e., will never delete a credential from the first object.
 *
 * @param credentials the object
 * @param which the credential to overwrite
 * @param other_credentials credentials to merge
 * @returns #FALSE if no memory
 */
dbus_bool_t _dbus_credentials_add_credential(DBusCredentials* credentials,
                                             DBusCredentialType which,
                                             DBusCredentials* other_credentials)
{
    if (which == DBUS_CREDENTIAL_UNIX_PROCESS_ID &&
        other_credentials->pid != DBUS_PID_UNSET)
    {
        if (!_dbus_credentials_add_pid(credentials, other_credentials->pid))
            return FALSE;
    }
    else if (which == DBUS_CREDENTIAL_UNIX_USER_ID &&
             other_credentials->unix_uid != DBUS_UID_UNSET)
    {
        if (!_dbus_credentials_add_unix_uid(credentials,
                                            other_credentials->unix_uid))
            return FALSE;
    }
    else if (which == DBUS_CREDENTIAL_WINDOWS_SID &&
             other_credentials->windows_sid != NULL)
    {
        if (!_dbus_credentials_add_windows_sid(credentials,
                                               other_credentials->windows_sid))
            return FALSE;
    }
    else if (which == DBUS_CREDENTIAL_LINUX_SECURITY_LABEL &&
             other_credentials->linux_security_label != NULL)
    {
        if (!_dbus_credentials_add_linux_security_label(
                credentials, other_credentials->linux_security_label))
            return FALSE;
    }
    else if (which == DBUS_CREDENTIAL_ADT_AUDIT_DATA_ID &&
             other_credentials->adt_audit_data != NULL)
    {
        if (!_dbus_credentials_add_adt_audit_data(
                credentials, other_credentials->adt_audit_data,
                other_credentials->adt_audit_data_size))
            return FALSE;
    }

    return TRUE;
}

/**
 * Clear all credentials in the object.
 *
 * @param credentials the object
 */
void _dbus_credentials_clear(DBusCredentials* credentials)
{
    credentials->pid = DBUS_PID_UNSET;
    credentials->unix_uid = DBUS_UID_UNSET;
    dbus_free(credentials->windows_sid);
    credentials->windows_sid = NULL;
    dbus_free(credentials->linux_security_label);
    credentials->linux_security_label = NULL;
    dbus_free(credentials->adt_audit_data);
    credentials->adt_audit_data = NULL;
    credentials->adt_audit_data_size = 0;
}

/**
 * Copy a credentials object.
 *
 * @param credentials the object
 * @returns the copy or #NULL
 */
DBusCredentials* _dbus_credentials_copy(DBusCredentials* credentials)
{
    DBusCredentials* copy;

    copy = _dbus_credentials_new();
    if (copy == NULL)
        return NULL;

    if (!_dbus_credentials_add_credentials(copy, credentials))
    {
        _dbus_credentials_unref(copy);
        return NULL;
    }

    return copy;
}

/**
 * Check whether the user-identifying credentials in two credentials
 * objects are identical. Credentials that are not related to the
 * user are ignored, but any kind of user ID credentials must be the
 * same (UNIX user ID, Windows user SID, etc.) and present in both
 * objects for the function to return #TRUE.
 *
 * @param credentials the object
 * @param other_credentials credentials to compare
 * @returns #TRUE if the two credentials refer to the same user
 */
dbus_bool_t _dbus_credentials_same_user(DBusCredentials* credentials,
                                        DBusCredentials* other_credentials)
{
    /* both windows and unix user must be the same (though pretty much
     * in all conceivable cases, one will be unset)
     */
    return credentials->unix_uid == other_credentials->unix_uid &&
           ((!(credentials->windows_sid || other_credentials->windows_sid)) ||
            (credentials->windows_sid && other_credentials->windows_sid &&
             strcmp(credentials->windows_sid, other_credentials->windows_sid) ==
                 0));
}

/**
 * Convert the credentials in this object to a human-readable
 * string format, and append to the given string.
 *
 * @param credentials the object
 * @param string append to this string
 * @returns #FALSE if no memory
 */
dbus_bool_t _dbus_credentials_to_string_append(DBusCredentials* credentials,
                                               DBusString* string)
{
    dbus_bool_t join;

    join = FALSE;
    if (credentials->unix_uid != DBUS_UID_UNSET)
    {
        if (!_dbus_string_append_printf(string, "uid=" DBUS_UID_FORMAT,
                                        credentials->unix_uid))
            goto oom;
        join = TRUE;
    }
    if (credentials->pid != DBUS_PID_UNSET)
    {
        if (!_dbus_string_append_printf(string, "%spid=" DBUS_PID_FORMAT,
                                        join ? " " : "", credentials->pid))
            goto oom;
        join = TRUE;
    }
    else
        join = FALSE;
    if (credentials->windows_sid != NULL)
    {
        if (!_dbus_string_append_printf(string, "%ssid=%s", join ? " " : "",
                                        credentials->windows_sid))
            goto oom;
        join = TRUE;
    }
    else
        join = FALSE;

    if (credentials->linux_security_label != NULL)
    {
        if (!_dbus_string_append_printf(string, "%slsm='%s'", join ? " " : "",
                                        credentials->linux_security_label))
            goto oom;
        join = TRUE;
    }

    return TRUE;
oom:
    return FALSE;
}

/** @} */

/* tests in dbus-credentials-util.c */
