/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * Copyright (C) 2015 Red Hat, Inc.
 */

#include "nm-default.h"

#include "nm-audit-manager.h"

#if HAVE_LIBAUDIT
    #include <libaudit.h>
#endif

#include "nm-libnm-core-intern/nm-auth-subject.h"
#include "nm-config.h"
#include "nm-dbus-manager.h"
#include "settings/nm-settings-connection.h"

/*****************************************************************************/

typedef enum {
    BACKEND_LOG    = (1 << 0),
    BACKEND_AUDITD = (1 << 1),
    _BACKEND_LAST,
    BACKEND_ALL = ((_BACKEND_LAST - 1) << 1) - 1,
} AuditBackend;

typedef struct {
    const char * name;
    GValue       value;
    gboolean     need_encoding;
    AuditBackend backends;
} AuditField;

/*****************************************************************************/

typedef struct {
    NMConfig *config;
    int       auditd_fd;
} NMAuditManagerPrivate;

struct _NMAuditManager {
    GObject parent;
#if HAVE_LIBAUDIT
    NMAuditManagerPrivate _priv;
#endif
};

struct _NMAuditManagerClass {
    GObjectClass parent;
};

G_DEFINE_TYPE(NMAuditManager, nm_audit_manager, G_TYPE_OBJECT)

#define NM_AUDIT_MANAGER_GET_PRIVATE(self) \
    _NM_GET_PRIVATE(self, NMAuditManager, NM_IS_AUDIT_MANAGER)

/*****************************************************************************/

#define AUDIT_LOG_LEVEL LOGL_INFO

#define _NMLOG_PREFIX_NAME "audit"
#define _NMLOG(level, domain, ...)                                         \
    G_STMT_START                                                           \
    {                                                                      \
        nm_log((level),                                                    \
               (domain),                                                   \
               NULL,                                                       \
               NULL,                                                       \
               "%s" _NM_UTILS_MACRO_FIRST(__VA_ARGS__),                    \
               _NMLOG_PREFIX_NAME ": " _NM_UTILS_MACRO_REST(__VA_ARGS__)); \
    }                                                                      \
    G_STMT_END

/*****************************************************************************/

NM_DEFINE_SINGLETON_GETTER(NMAuditManager, nm_audit_manager_get, NM_TYPE_AUDIT_MANAGER);

/*****************************************************************************/

static void
_audit_field_init_string(AuditField * field,
                         const char * name,
                         const char * str,
                         gboolean     need_encoding,
                         AuditBackend backends)
{
    field->name          = name;
    field->need_encoding = need_encoding;
    field->backends      = backends;
    g_value_init(&field->value, G_TYPE_STRING);
    g_value_set_static_string(&field->value, str);
}

static void
_audit_field_init_uint(AuditField *field, const char *name, uint val, AuditBackend backends)
{
    field->name     = name;
    field->backends = backends;
    g_value_init(&field->value, G_TYPE_UINT);
    g_value_set_uint(&field->value, val);
}

static char *
build_message(GPtrArray *fields, AuditBackend backend)
{
    GString *   string;
    AuditField *field;
    gboolean    first = TRUE;
    guint       i;

    string = g_string_new(NULL);

    for (i = 0; i < fields->len; i++) {
        field = fields->pdata[i];

        if (!NM_FLAGS_ANY(field->backends, backend))
            continue;

        if (first)
            first = FALSE;
        else
            g_string_append_c(string, ' ');

        if (G_VALUE_HOLDS_STRING(&field->value)) {
            const char *str = g_value_get_string(&field->value);

#if HAVE_LIBAUDIT
            if (backend == BACKEND_AUDITD) {
                if (field->need_encoding) {
                    char *value;

                    value = audit_encode_nv_string(field->name, str, 0);
                    g_string_append(string, value);
                    g_free(value);
                } else
                    g_string_append_printf(string, "%s=%s", field->name, str);
                continue;
            }
#endif /* HAVE_LIBAUDIT */
            g_string_append_printf(string, "%s=\"%s\"", field->name, str);
        } else if (G_VALUE_HOLDS_UINT(&field->value)) {
            g_string_append_printf(string, "%s=%u", field->name, g_value_get_uint(&field->value));
        } else
            g_assert_not_reached();
    }
    return g_string_free(string, FALSE);
}

static void
nm_audit_log(NMAuditManager *self,
             GPtrArray *     fields,
             const char *    file,
             guint           line,
             const char *    func,
             gboolean        success)
{
#if HAVE_LIBAUDIT
    NMAuditManagerPrivate *priv;
#endif
    char *msg;

    g_return_if_fail(NM_IS_AUDIT_MANAGER(self));

#if HAVE_LIBAUDIT
    priv = NM_AUDIT_MANAGER_GET_PRIVATE(self);

    if (priv->auditd_fd >= 0) {
        msg = build_message(fields, BACKEND_AUDITD);
        audit_log_user_message(priv->auditd_fd, AUDIT_USYS_CONFIG, msg, NULL, NULL, NULL, success);
        g_free(msg);
    }
#endif

    if (nm_logging_enabled(AUDIT_LOG_LEVEL, LOGD_AUDIT)) {
        msg = build_message(fields, BACKEND_LOG);
        _NMLOG(AUDIT_LOG_LEVEL, LOGD_AUDIT, "%s", msg);
        g_free(msg);
    }
}

static void
_audit_log_helper(NMAuditManager *self,
                  GPtrArray *     fields,
                  const char *    file,
                  guint           line,
                  const char *    func,
                  const char *    op,
                  gboolean        result,
                  gpointer        subject_context,
                  const char *    reason)
{
    AuditField      op_field = {}, pid_field = {}, uid_field = {};
    AuditField      result_field = {}, reason_field = {};
    gulong          pid, uid;
    NMAuthSubject * subject                     = NULL;
    gs_unref_object NMAuthSubject *subject_free = NULL;

    _audit_field_init_string(&op_field, "op", op, FALSE, BACKEND_ALL);
    g_ptr_array_insert(fields, 0, &op_field);

    if (subject_context) {
        if (NM_IS_AUTH_SUBJECT(subject_context))
            subject = subject_context;
        else if (G_IS_DBUS_METHOD_INVOCATION(subject_context)) {
            GDBusMethodInvocation *context = subject_context;

            subject = subject_free = nm_dbus_manager_new_auth_subject_from_context(context);
        } else
            g_warn_if_reached();
    }
    if (subject && nm_auth_subject_get_subject_type(subject) == NM_AUTH_SUBJECT_TYPE_UNIX_PROCESS) {
        pid = nm_auth_subject_get_unix_process_pid(subject);
        uid = nm_auth_subject_get_unix_process_uid(subject);
        if (pid != G_MAXULONG) {
            _audit_field_init_uint(&pid_field, "pid", pid, BACKEND_ALL);
            g_ptr_array_add(fields, &pid_field);
        }
        if (uid != G_MAXULONG) {
            _audit_field_init_uint(&uid_field, "uid", uid, BACKEND_ALL);
            g_ptr_array_add(fields, &uid_field);
        }
    }

    _audit_field_init_string(&result_field,
                             "result",
                             result ? "success" : "fail",
                             FALSE,
                             BACKEND_ALL);
    g_ptr_array_add(fields, &result_field);

    if (reason) {
        _audit_field_init_string(&reason_field, "reason", reason, FALSE, BACKEND_LOG);
        g_ptr_array_add(fields, &reason_field);
    }

    nm_audit_log(self, fields, file, line, func, result);
}

gboolean
nm_audit_manager_audit_enabled(NMAuditManager *self)
{
#if HAVE_LIBAUDIT
    NMAuditManagerPrivate *priv = NM_AUDIT_MANAGER_GET_PRIVATE(self);

    if (priv->auditd_fd >= 0)
        return TRUE;
#endif

    return nm_logging_enabled(AUDIT_LOG_LEVEL, LOGD_AUDIT);
}

void
_nm_audit_manager_log_connection_op(NMAuditManager *      self,
                                    const char *          file,
                                    guint                 line,
                                    const char *          func,
                                    const char *          op,
                                    NMSettingsConnection *connection,
                                    gboolean              result,
                                    const char *          args,
                                    gpointer              subject_context,
                                    const char *          reason)
{
    gs_unref_ptrarray GPtrArray *fields     = NULL;
    AuditField                   uuid_field = {}, name_field = {}, args_field = {};

    g_return_if_fail(op);

    fields = g_ptr_array_new();

    if (connection) {
        _audit_field_init_string(&uuid_field,
                                 "uuid",
                                 nm_settings_connection_get_uuid(connection),
                                 FALSE,
                                 BACKEND_ALL);
        g_ptr_array_add(fields, &uuid_field);

        _audit_field_init_string(&name_field,
                                 "name",
                                 nm_settings_connection_get_id(connection),
                                 TRUE,
                                 BACKEND_ALL);
        g_ptr_array_add(fields, &name_field);
    }

    if (args) {
        _audit_field_init_string(&args_field, "args", args, FALSE, BACKEND_ALL);
        g_ptr_array_add(fields, &args_field);
    }

    _audit_log_helper(self, fields, file, line, func, op, result, subject_context, reason);
}

void
_nm_audit_manager_log_generic_op(NMAuditManager *self,
                                 const char *    file,
                                 guint           line,
                                 const char *    func,
                                 const char *    op,
                                 const char *    arg,
                                 gboolean        result,
                                 gpointer        subject_context,
                                 const char *    reason)
{
    gs_unref_ptrarray GPtrArray *fields    = NULL;
    AuditField                   arg_field = {};

    g_return_if_fail(op);
    g_return_if_fail(arg);

    fields = g_ptr_array_new();

    _audit_field_init_string(&arg_field, "arg", arg, TRUE, BACKEND_ALL);
    g_ptr_array_add(fields, &arg_field);

    _audit_log_helper(self, fields, file, line, func, op, result, subject_context, reason);
}

void
_nm_audit_manager_log_device_op(NMAuditManager *self,
                                const char *    file,
                                guint           line,
                                const char *    func,
                                const char *    op,
                                NMDevice *      device,
                                gboolean        result,
                                const char *    args,
                                gpointer        subject_context,
                                const char *    reason)
{
    gs_unref_ptrarray GPtrArray *fields          = NULL;
    AuditField                   interface_field = {}, ifindex_field = {}, args_field = {};
    int                          ifindex;

    g_return_if_fail(op);
    g_return_if_fail(device);

    fields = g_ptr_array_new();

    _audit_field_init_string(&interface_field,
                             "interface",
                             nm_device_get_ip_iface(device),
                             TRUE,
                             BACKEND_ALL);
    g_ptr_array_add(fields, &interface_field);

    ifindex = nm_device_get_ip_ifindex(device);
    if (ifindex > 0) {
        _audit_field_init_uint(&ifindex_field, "ifindex", ifindex, BACKEND_ALL);
        g_ptr_array_add(fields, &ifindex_field);
    }

    if (args) {
        _audit_field_init_string(&args_field, "args", args, FALSE, BACKEND_ALL);
        g_ptr_array_add(fields, &args_field);
    }

    _audit_log_helper(self, fields, file, line, func, op, result, subject_context, reason);
}

#if HAVE_LIBAUDIT
static void
init_auditd(NMAuditManager *self)
{
    NMAuditManagerPrivate *priv = NM_AUDIT_MANAGER_GET_PRIVATE(self);
    NMConfigData *         data = nm_config_get_data(priv->config);
    int                    errsv;

    if (nm_config_data_get_value_boolean(data,
                                         NM_CONFIG_KEYFILE_GROUP_LOGGING,
                                         NM_CONFIG_KEYFILE_KEY_LOGGING_AUDIT,
                                         NM_CONFIG_DEFAULT_LOGGING_AUDIT_BOOL)) {
        if (priv->auditd_fd < 0) {
            priv->auditd_fd = audit_open();
            if (priv->auditd_fd < 0) {
                errsv = errno;
                _LOGE(LOGD_CORE, "failed to open auditd socket: %s", nm_strerror_native(errsv));
            } else
                _LOGD(LOGD_CORE, "socket created");
        }
    } else {
        if (priv->auditd_fd >= 0) {
            audit_close(priv->auditd_fd);
            priv->auditd_fd = -1;
            _LOGD(LOGD_CORE, "socket closed");
        }
    }
}

static void
config_changed_cb(NMConfig *          config,
                  NMConfigData *      config_data,
                  NMConfigChangeFlags changes,
                  NMConfigData *      old_data,
                  NMAuditManager *    self)
{
    if (NM_FLAGS_HAS(changes, NM_CONFIG_CHANGE_VALUES))
        init_auditd(self);
}
#endif

/*****************************************************************************/

static void
nm_audit_manager_init(NMAuditManager *self)
{
#if HAVE_LIBAUDIT
    NMAuditManagerPrivate *priv = NM_AUDIT_MANAGER_GET_PRIVATE(self);

    priv->config = g_object_ref(nm_config_get());
    g_signal_connect(G_OBJECT(priv->config),
                     NM_CONFIG_SIGNAL_CONFIG_CHANGED,
                     G_CALLBACK(config_changed_cb),
                     self);
    priv->auditd_fd = -1;

    init_auditd(self);
#endif
}

static void
dispose(GObject *object)
{
#if HAVE_LIBAUDIT
    NMAuditManager *       self = NM_AUDIT_MANAGER(object);
    NMAuditManagerPrivate *priv = NM_AUDIT_MANAGER_GET_PRIVATE(self);

    if (priv->config) {
        g_signal_handlers_disconnect_by_func(priv->config, config_changed_cb, self);
        g_clear_object(&priv->config);
    }

    if (priv->auditd_fd >= 0) {
        audit_close(priv->auditd_fd);
        priv->auditd_fd = -1;
    }
#endif

    G_OBJECT_CLASS(nm_audit_manager_parent_class)->dispose(object);
}

static void
nm_audit_manager_class_init(NMAuditManagerClass *klass)
{
    GObjectClass *object_class = G_OBJECT_CLASS(klass);

    object_class->dispose = dispose;
}