New upstream version 1.29.90 upstream/1.29.90

1 files changed, 696 insertions, 0 deletions

diff --git a/src/core/nm-auth-utils.c b/src/core/nm-auth-utils.c
new file mode 100644
index 00000000..12da5749
--- /dev/null
+++ b/src/core/nm-auth-utils.c
@@ -0,0 +1,696 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2010 Red Hat, Inc.
+ */
+
+#include "src/core/nm-default-daemon.h"
+
+#include "nm-auth-utils.h"
+
+#include "nm-glib-aux/nm-c-list.h"
+#include "nm-setting-connection.h"
+#include "nm-libnm-core-intern/nm-auth-subject.h"
+#include "nm-auth-manager.h"
+#include "nm-session-monitor.h"
+#include "nm-dbus-manager.h"
+#include "nm-core-utils.h"
+
+/*****************************************************************************/
+
+typedef struct {
+    const char *   tag;
+    gpointer       data;
+    GDestroyNotify destroy;
+} ChainData;
+
+struct _NMAuthChain {
+    CList parent_lst;
+
+    ChainData *data_arr;
+    guint      data_len;
+    guint      data_alloc;
+
+    CList auth_call_lst_head;
+
+    GDBusMethodInvocation *context;
+    NMAuthSubject *        subject;
+
+    GCancellable *cancellable;
+
+    /* if set, it also means that the chain is already started and was cancelled. */
+    GSource *cancellable_idle_source;
+
+    NMAuthChainResultFunc done_func;
+    gpointer              user_data;
+
+    gulong cancellable_id;
+
+    guint num_pending_auth_calls;
+
+    bool is_started : 1;
+    bool is_destroyed : 1;
+    bool is_finishing : 1;
+};
+
+G_STATIC_ASSERT(G_STRUCT_OFFSET(NMAuthChain, parent_lst) == 0);
+
+typedef struct {
+    CList                auth_call_lst;
+    NMAuthChain *        chain;
+    NMAuthManagerCallId *call_id;
+    const char *         permission;
+    NMAuthCallResult     result;
+} AuthCall;
+
+/*****************************************************************************/
+
+static void _auth_chain_destroy(NMAuthChain *self);
+
+/*****************************************************************************/
+
+static void
+_ASSERT_call(AuthCall *call)
+{
+    nm_assert(call);
+    nm_assert(call->chain);
+    nm_assert(call->permission && strlen(call->permission) > 0);
+    nm_assert(nm_c_list_contains_entry(&call->chain->auth_call_lst_head, call, auth_call_lst));
+#if NM_MORE_ASSERTS > 5
+    {
+        AuthCall *auth_call;
+        guint     n = 0;
+
+        c_list_for_each_entry (auth_call, &call->chain->auth_call_lst_head, auth_call_lst) {
+            nm_assert(auth_call->result == NM_AUTH_CALL_RESULT_UNKNOWN || !auth_call->call_id);
+            if (auth_call->call_id)
+                n++;
+        }
+        nm_assert(n == call->chain->num_pending_auth_calls);
+    }
+#endif
+}
+
+/*****************************************************************************/
+
+static void
+_done_and_destroy(NMAuthChain *self)
+{
+    self->is_finishing = TRUE;
+    self->done_func(self, self->context, self->user_data);
+    nm_assert(self->is_finishing);
+    _auth_chain_destroy(self);
+}
+
+static gboolean
+_cancellable_idle_cb(gpointer user_data)
+{
+    NMAuthChain *self = user_data;
+    AuthCall *   call;
+
+    nm_assert(g_cancellable_is_cancelled(self->cancellable));
+    nm_assert(self->cancellable_idle_source);
+
+    c_list_for_each_entry (call, &self->auth_call_lst_head, auth_call_lst) {
+        if (call->call_id) {
+            self->num_pending_auth_calls--;
+            nm_auth_manager_check_authorization_cancel(g_steal_pointer(&call->call_id));
+        }
+    }
+
+    _done_and_destroy(self);
+    return G_SOURCE_REMOVE;
+}
+
+static void
+_cancellable_on_idle(NMAuthChain *self)
+{
+    if (self->cancellable_idle_source)
+        return;
+
+    self->cancellable_idle_source =
+        nm_g_idle_source_new(G_PRIORITY_DEFAULT, _cancellable_idle_cb, self, NULL);
+    g_source_attach(self->cancellable_idle_source, NULL);
+}
+
+GCancellable *
+nm_auth_chain_get_cancellable(NMAuthChain *self)
+{
+    return self->cancellable;
+}
+
+static void
+_cancellable_cancelled(GCancellable *cancellable, NMAuthChain *self)
+{
+    _cancellable_on_idle(self);
+}
+
+void
+nm_auth_chain_set_cancellable(NMAuthChain *self, GCancellable *cancellable)
+{
+    g_return_if_fail(self);
+    g_return_if_fail(G_IS_CANCELLABLE(cancellable));
+
+    /* after the chain is started, the cancellable can no longer be changed.
+     * No need to handle the complexity of swapping the cancellable *after*
+     * requests are already started. */
+    g_return_if_fail(!self->is_started);
+    nm_assert(c_list_is_empty(&self->auth_call_lst_head));
+
+    /* also no need to allow setting different cancellables. */
+    g_return_if_fail(!self->cancellable);
+
+    self->cancellable = g_object_ref(cancellable);
+}
+
+/*****************************************************************************/
+
+static void
+auth_call_free(AuthCall *call)
+{
+    _ASSERT_call(call);
+
+    c_list_unlink_stale(&call->auth_call_lst);
+    if (call->call_id) {
+        call->chain->num_pending_auth_calls--;
+        nm_auth_manager_check_authorization_cancel(call->call_id);
+    }
+    nm_g_slice_free(call);
+}
+
+static AuthCall *
+_find_auth_call(NMAuthChain *self, const char *permission)
+{
+    AuthCall *auth_call;
+
+    c_list_for_each_entry (auth_call, &self->auth_call_lst_head, auth_call_lst) {
+        if (nm_streq(auth_call->permission, permission))
+            return auth_call;
+    }
+    return NULL;
+}
+
+/*****************************************************************************/
+
+static ChainData *
+_get_data(NMAuthChain *self, const char *tag)
+{
+    guint i;
+
+    for (i = 0; i < self->data_len; i++) {
+        ChainData *chain_data = &self->data_arr[i];
+
+        if (chain_data->tag && nm_streq(chain_data->tag, tag))
+            return chain_data;
+    }
+    return NULL;
+}
+
+gpointer
+nm_auth_chain_get_data(NMAuthChain *self, const char *tag)
+{
+    ChainData *chain_data;
+
+    g_return_val_if_fail(self, NULL);
+    g_return_val_if_fail(tag, NULL);
+
+    chain_data = _get_data(self, tag);
+    return chain_data ? chain_data->data : NULL;
+}
+
+/**
+ * nm_auth_chain_steal_data:
+ * @self: A #NMAuthChain.
+ * @tag: A "tag" uniquely identifying the data to steal.
+ *
+ * Removes the datum associated with @tag from the chain's data associations,
+ * without invoking the association's destroy handler.  The caller assumes
+ * ownership over the returned value.
+ *
+ * Returns: the datum originally associated with @tag
+ */
+gpointer
+nm_auth_chain_steal_data(NMAuthChain *self, const char *tag)
+{
+    ChainData *chain_data;
+
+    g_return_val_if_fail(self, NULL);
+    g_return_val_if_fail(tag, NULL);
+
+    chain_data = _get_data(self, tag);
+    if (!chain_data)
+        return NULL;
+
+    /* Make sure the destroy handler isn't called when freeing.
+     *
+     * We don't bother to really remove the element from the array.
+     * Just mark the entry as unused by clearing the tag. */
+    chain_data->destroy = NULL;
+    chain_data->tag     = NULL;
+    return chain_data->data;
+}
+
+/**
+ * nm_auth_chain_set_data_unsafe:
+ * @self: the #NMAuthChain
+ * @tag: the tag for referencing the attached data.
+ * @data: the data to attach. If %NULL, this call has no effect
+ *   and nothing is attached.
+ * @data_destroy: (allow-none): the destroy function for the data pointer.
+ *
+ * @tag string is not cloned and must outlive @self. That is why
+ * the function is "unsafe". Use nm_auth_chain_set_data() with a C literal
+ * instead.
+ *
+ * It is a bug to add the same tag more than once.
+ */
+void
+nm_auth_chain_set_data_unsafe(NMAuthChain *  self,
+                              const char *   tag,
+                              gpointer       data,
+                              GDestroyNotify data_destroy)
+{
+    ChainData *chain_data;
+
+    g_return_if_fail(self);
+    g_return_if_fail(tag);
+
+    /* The tag must not yet exist. Otherwise, we'd have to first search the
+     * list for an existing entry. That usage pattern is not supported. */
+    nm_assert(!_get_data(self, tag));
+
+    if (!data) {
+        /* we don't track user data of %NULL.
+         *
+         * In the past this had also the meaning of removing a user-data. But since
+         * nm_auth_chain_set_data() does not allow being called more than once
+         * for the same tag, we don't need to remove anything. */
+        return;
+    }
+
+    if (self->data_len + 1 > self->data_alloc) {
+        if (self->data_alloc == 0)
+            self->data_alloc = 8;
+        else
+            self->data_alloc *= 2;
+        self->data_arr = g_realloc(self->data_arr, sizeof(self->data_arr[0]) * self->data_alloc);
+    }
+
+    chain_data  = &self->data_arr[self->data_len++];
+    *chain_data = (ChainData){
+        .tag     = tag,
+        .data    = data,
+        .destroy = data_destroy,
+    };
+}
+
+/*****************************************************************************/
+
+NMAuthCallResult
+nm_auth_chain_get_result(NMAuthChain *self, const char *permission)
+{
+    AuthCall *auth_call;
+
+    g_return_val_if_fail(self, NM_AUTH_CALL_RESULT_UNKNOWN);
+    g_return_val_if_fail(permission, NM_AUTH_CALL_RESULT_UNKNOWN);
+
+    /* it is a bug to request the result other than from the done_func()
+     * callback. You are not supposed to poll for the result but request
+     * it upon notification. */
+    nm_assert(self->is_finishing);
+
+    auth_call = _find_auth_call(self, permission);
+
+    /* it is a bug to request a permission result that was not
+     * previously requested or which did not complete yet. */
+    if (!auth_call)
+        g_return_val_if_reached(NM_AUTH_CALL_RESULT_UNKNOWN);
+
+    nm_assert(!auth_call->call_id);
+
+    if (self->cancellable_idle_source) {
+        /* already cancelled. We always return unknown (even if we happen to
+         * have already received the response. */
+        return NM_AUTH_CALL_RESULT_UNKNOWN;
+    }
+
+    return auth_call->result;
+}
+
+NMAuthSubject *
+nm_auth_chain_get_subject(NMAuthChain *self)
+{
+    g_return_val_if_fail(self, NULL);
+
+    return self->subject;
+}
+
+GDBusMethodInvocation *
+nm_auth_chain_get_context(NMAuthChain *self)
+{
+    g_return_val_if_fail(self, NULL);
+
+    return self->context;
+}
+
+/*****************************************************************************/
+
+static void
+pk_call_cb(NMAuthManager *      auth_manager,
+           NMAuthManagerCallId *call_id,
+           gboolean             is_authorized,
+           gboolean             is_challenge,
+           GError *             error,
+           gpointer             user_data)
+{
+    NMAuthChain *self;
+    AuthCall *   call;
+
+    nm_assert(call_id);
+
+    if (g_error_matches(error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
+        return;
+
+    call = user_data;
+
+    _ASSERT_call(call);
+    nm_assert(call->call_id == call_id);
+    nm_assert(call->result == NM_AUTH_CALL_RESULT_UNKNOWN);
+
+    self = call->chain;
+
+    nm_assert(!self->is_destroyed);
+    nm_assert(!self->is_finishing);
+
+    call->call_id = NULL;
+
+    call->result = nm_auth_call_result_eval(is_authorized, is_challenge, error);
+
+    call->chain->num_pending_auth_calls--;
+
+    _ASSERT_call(call);
+
+    if (call->chain->num_pending_auth_calls == 0) {
+        /* we are on an idle-handler or a clean call-stack (non-reentrant) so it's safe
+         * to invoke the callback right away. */
+        _done_and_destroy(self);
+    }
+}
+
+/**
+ * nm_auth_chain_add_call_unsafe:
+ * @self: the #NMAuthChain
+ * @permission: the permission string. This string is kept by reference
+ *   and you must make sure that it's lifetime lasts until the NMAuthChain
+ *   gets destroyed. That's why the function is "unsafe". Use
+ *   nm_auth_chain_add_call() instead.
+ * @allow_interaction: flag
+ *
+ * It's "unsafe" because @permission is not copied. It's the callers responsibility
+ * that the permission string stays valid as long as NMAuthChain.
+ *
+ * If you can, use nm_auth_chain_add_call() instead!
+ *
+ * If you have a non-static string, you may attach the permission string as
+ * user-data via nm_auth_chain_set_data().
+ */
+void
+nm_auth_chain_add_call_unsafe(NMAuthChain *self, const char *permission, gboolean allow_interaction)
+{
+    AuthCall *call;
+
+    g_return_if_fail(self);
+    g_return_if_fail(self->subject);
+    g_return_if_fail(!self->is_finishing);
+    g_return_if_fail(!self->is_destroyed);
+    g_return_if_fail(permission && *permission);
+    nm_assert(NM_IN_SET(nm_auth_subject_get_subject_type(self->subject),
+                        NM_AUTH_SUBJECT_TYPE_UNIX_PROCESS,
+                        NM_AUTH_SUBJECT_TYPE_INTERNAL));
+
+    /* duplicate permissions are not supported, also because nm_auth_chain_get_result()
+     * can only return one-permission. */
+    nm_assert(!_find_auth_call(self, permission));
+
+    if (!self->is_started) {
+        self->is_started = TRUE;
+        nm_assert(!self->cancellable_id);
+        if (self->cancellable) {
+            if (g_cancellable_is_cancelled(self->cancellable)) {
+                /* the operation is already cancelled. Schedule the callback on idle. */
+                _cancellable_on_idle(self);
+            } else {
+                self->cancellable_id = g_signal_connect(self->cancellable,
+                                                        "cancelled",
+                                                        G_CALLBACK(_cancellable_cancelled),
+                                                        self);
+            }
+        }
+    }
+
+    call  = g_slice_new(AuthCall);
+    *call = (AuthCall){
+        .chain   = self,
+        .call_id = NULL,
+        .result  = NM_AUTH_CALL_RESULT_UNKNOWN,
+
+        /* we don't clone the permission string. It's the callers responsibility. */
+        .permission = permission,
+    };
+
+    /* above we assert that no duplicate permissions are added. Still, track the
+     * new request to the front of the list so that it would shadow an earlier
+     * call. */
+    c_list_link_front(&self->auth_call_lst_head, &call->auth_call_lst);
+
+    if (self->cancellable_idle_source) {
+        /* already cancelled. No need to actually start the request. */
+        nm_assert(call->result == NM_AUTH_CALL_RESULT_UNKNOWN);
+    } else {
+        call->call_id = nm_auth_manager_check_authorization(nm_auth_manager_get(),
+                                                            self->subject,
+                                                            permission,
+                                                            allow_interaction,
+                                                            pk_call_cb,
+                                                            call);
+
+        self->num_pending_auth_calls++;
+    }
+
+    _ASSERT_call(call);
+
+    /* we track auth-calls in a linked list. If we end up requesting too many permissions this
+     * becomes inefficient. If that ever happens, consider a more efficient data structure for
+     * a large number of requests. */
+    nm_assert(c_list_length(&self->auth_call_lst_head) < 25);
+    G_STATIC_ASSERT_EXPR(NM_CLIENT_PERMISSION_LAST < 25);
+}
+
+/*****************************************************************************/
+
+/* Creates the NMAuthSubject automatically */
+NMAuthChain *
+nm_auth_chain_new_context(GDBusMethodInvocation *context,
+                          NMAuthChainResultFunc  done_func,
+                          gpointer               user_data)
+{
+    NMAuthSubject *subject;
+    NMAuthChain *  chain;
+
+    g_return_val_if_fail(context, NULL);
+    nm_assert(done_func);
+
+    subject = nm_dbus_manager_new_auth_subject_from_context(context);
+    if (!subject)
+        return NULL;
+
+    chain = nm_auth_chain_new_subject(subject, context, done_func, user_data);
+    g_object_unref(subject);
+    return chain;
+}
+
+NMAuthChain *
+nm_auth_chain_new_subject(NMAuthSubject *        subject,
+                          GDBusMethodInvocation *context,
+                          NMAuthChainResultFunc  done_func,
+                          gpointer               user_data)
+{
+    NMAuthChain *self;
+
+    g_return_val_if_fail(NM_IS_AUTH_SUBJECT(subject), NULL);
+    nm_assert(NM_IN_SET(nm_auth_subject_get_subject_type(subject),
+                        NM_AUTH_SUBJECT_TYPE_UNIX_PROCESS,
+                        NM_AUTH_SUBJECT_TYPE_INTERNAL));
+    nm_assert(done_func);
+
+    self  = g_slice_new(NMAuthChain);
+    *self = (NMAuthChain){
+        .done_func          = done_func,
+        .user_data          = user_data,
+        .context            = nm_g_object_ref(context),
+        .subject            = g_object_ref(subject),
+        .parent_lst         = C_LIST_INIT(self->parent_lst),
+        .auth_call_lst_head = C_LIST_INIT(self->auth_call_lst_head),
+    };
+    return self;
+}
+
+/**
+ * nm_auth_chain_destroy:
+ * @self: the auth-chain
+ *
+ * Destroys the auth-chain. By destroying the auth-chain, you also cancel
+ * the receipt of the done-callback. IOW, the callback will not be invoked.
+ *
+ * The only exception is, you may call nm_auth_chain_destroy() from inside
+ * the callback. In this case the call has no effect and @self stays alive
+ * until the callback returns.
+ *
+ * Note that you might only destroy an auth-chain exactly once, and never
+ * after the callback was handled. After the callback returns, the auth chain
+ * always gets automatically destroyed. So you only need to explicitly destroy
+ * it, if you want to abort it before the callback complets.
+ */
+void
+nm_auth_chain_destroy(NMAuthChain *self)
+{
+    g_return_if_fail(self);
+    g_return_if_fail(!self->is_destroyed);
+
+    self->is_destroyed = TRUE;
+
+    if (self->is_finishing) {
+        /* we are called from inside the callback. Keep the instance alive for the moment. */
+        return;
+    }
+
+    _auth_chain_destroy(self);
+}
+
+static void
+_auth_chain_destroy(NMAuthChain *self)
+{
+    AuthCall *call;
+
+    c_list_unlink(&self->parent_lst);
+
+    nm_clear_g_object(&self->subject);
+    nm_clear_g_object(&self->context);
+
+    nm_clear_g_signal_handler(self->cancellable, &self->cancellable_id);
+    nm_clear_g_source_inst(&self->cancellable_idle_source);
+
+    /* we must first destroy all AuthCall instances before ChainData. The reason is
+     * that AuthData.permission is not cloned and the lifetime of the string must
+     * be ensured by the caller. A sensible thing to do for the caller is attach the
+     * permission string via nm_auth_chain_set_data(). Hence, first free the AuthCall. */
+    while ((call = c_list_first_entry(&self->auth_call_lst_head, AuthCall, auth_call_lst)))
+        auth_call_free(call);
+
+    while (self->data_len > 0) {
+        ChainData *chain_data = &self->data_arr[--self->data_len];
+
+        if (chain_data->destroy)
+            chain_data->destroy(chain_data->data);
+    }
+    g_free(self->data_arr);
+
+    nm_g_object_unref(self->cancellable);
+
+    nm_g_slice_free(self);
+}
+
+/******************************************************************************
+ * utils
+ *****************************************************************************/
+
+gboolean
+nm_auth_is_subject_in_acl(NMConnection *connection, NMAuthSubject *subject, char **out_error_desc)
+{
+    NMSettingConnection *s_con;
+    gs_free char *       user = NULL;
+    gulong               uid;
+
+    g_return_val_if_fail(connection, FALSE);
+    g_return_val_if_fail(NM_IS_AUTH_SUBJECT(subject), FALSE);
+    nm_assert(NM_IN_SET(nm_auth_subject_get_subject_type(subject),
+                        NM_AUTH_SUBJECT_TYPE_UNIX_PROCESS,
+                        NM_AUTH_SUBJECT_TYPE_INTERNAL));
+
+    if (nm_auth_subject_get_subject_type(subject) == NM_AUTH_SUBJECT_TYPE_INTERNAL)
+        return TRUE;
+
+    uid = nm_auth_subject_get_unix_process_uid(subject);
+
+    /* Root gets a free pass */
+    if (0 == uid)
+        return TRUE;
+
+    user = nm_utils_uid_to_name(uid);
+    if (!user) {
+        NM_SET_OUT(out_error_desc,
+                   g_strdup_printf("Could not determine username for uid %lu", uid));
+        return FALSE;
+    }
+
+    s_con = nm_connection_get_setting_connection(connection);
+    if (!s_con) {
+        /* This can only happen when called from AddAndActivate, so we know
+         * the user will be authorized when the connection is completed.
+         */
+        return TRUE;
+    }
+
+    /* Match the username returned by the session check to a user in the ACL */
+    if (!nm_setting_connection_permissions_user_allowed(s_con, user)) {
+        NM_SET_OUT(out_error_desc,
+                   g_strdup_printf("uid %lu has no permission to perform this operation", uid));
+        return FALSE;
+    }
+
+    return TRUE;
+}
+
+gboolean
+nm_auth_is_subject_in_acl_set_error(NMConnection * connection,
+                                    NMAuthSubject *subject,
+                                    GQuark         err_domain,
+                                    int            err_code,
+                                    GError **      error)
+{
+    char *error_desc = NULL;
+
+    nm_assert(!error || !*error);
+
+    if (nm_auth_is_subject_in_acl(connection, subject, error ? &error_desc : NULL))
+        return TRUE;
+
+    g_set_error_literal(error, err_domain, err_code, error_desc);
+    g_free(error_desc);
+    return FALSE;
+}
+
+gboolean
+nm_auth_is_invocation_in_acl_set_error(NMConnection *         connection,
+                                       GDBusMethodInvocation *invocation,
+                                       GQuark                 err_domain,
+                                       int                    err_code,
+                                       NMAuthSubject **       out_subject,
+                                       GError **              error)
+{
+    gs_unref_object NMAuthSubject *subject = NULL;
+    gboolean                       success;
+
+    nm_assert(!out_subject || !*out_subject);
+
+    subject = nm_dbus_manager_new_auth_subject_from_context(invocation);
+    if (!subject) {
+        g_set_error_literal(error, err_domain, err_code, NM_UTILS_ERROR_MSG_REQ_UID_UKNOWN);
+        return FALSE;
+    }
+
+    success = nm_auth_is_subject_in_acl_set_error(connection, subject, err_domain, err_code, error);
+
+    NM_SET_OUT(out_subject, g_steal_pointer(&subject));
+
+    return success;
+}