summaryrefslogtreecommitdiffstats
path: root/src/shared/bus-polkit.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/shared/bus-polkit.c')
-rw-r--r--src/shared/bus-polkit.c415
1 files changed, 415 insertions, 0 deletions
diff --git a/src/shared/bus-polkit.c b/src/shared/bus-polkit.c
new file mode 100644
index 0000000..14122e0
--- /dev/null
+++ b/src/shared/bus-polkit.c
@@ -0,0 +1,415 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "bus-internal.h"
+#include "bus-message.h"
+#include "bus-polkit.h"
+#include "bus-util.h"
+#include "strv.h"
+#include "user-util.h"
+
+static int check_good_user(sd_bus_message *m, uid_t good_user) {
+ _cleanup_(sd_bus_creds_unrefp) sd_bus_creds *creds = NULL;
+ uid_t sender_uid;
+ int r;
+
+ assert(m);
+
+ if (good_user == UID_INVALID)
+ return 0;
+
+ r = sd_bus_query_sender_creds(m, SD_BUS_CREDS_EUID, &creds);
+ if (r < 0)
+ return r;
+
+ /* Don't trust augmented credentials for authorization */
+ assert_return((sd_bus_creds_get_augmented_mask(creds) & SD_BUS_CREDS_EUID) == 0, -EPERM);
+
+ r = sd_bus_creds_get_euid(creds, &sender_uid);
+ if (r < 0)
+ return r;
+
+ return sender_uid == good_user;
+}
+
+#if ENABLE_POLKIT
+static int bus_message_append_strv_key_value(
+ sd_bus_message *m,
+ const char **l) {
+
+ const char **k, **v;
+ int r;
+
+ assert(m);
+
+ r = sd_bus_message_open_container(m, 'a', "{ss}");
+ if (r < 0)
+ return r;
+
+ STRV_FOREACH_PAIR(k, v, l) {
+ r = sd_bus_message_append(m, "{ss}", *k, *v);
+ if (r < 0)
+ return r;
+ }
+
+ r = sd_bus_message_close_container(m);
+ if (r < 0)
+ return r;
+
+ return r;
+}
+#endif
+
+int bus_test_polkit(
+ sd_bus_message *call,
+ int capability,
+ const char *action,
+ const char **details,
+ uid_t good_user,
+ bool *_challenge,
+ sd_bus_error *ret_error) {
+
+ int r;
+
+ assert(call);
+ assert(action);
+
+ /* Tests non-interactively! */
+
+ r = check_good_user(call, good_user);
+ if (r != 0)
+ return r;
+
+ r = sd_bus_query_sender_privilege(call, capability);
+ if (r < 0)
+ return r;
+ else if (r > 0)
+ return 1;
+#if ENABLE_POLKIT
+ else {
+ _cleanup_(sd_bus_message_unrefp) sd_bus_message *request = NULL;
+ _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+ int authorized = false, challenge = false;
+ const char *sender;
+
+ sender = sd_bus_message_get_sender(call);
+ if (!sender)
+ return -EBADMSG;
+
+ r = sd_bus_message_new_method_call(
+ call->bus,
+ &request,
+ "org.freedesktop.PolicyKit1",
+ "/org/freedesktop/PolicyKit1/Authority",
+ "org.freedesktop.PolicyKit1.Authority",
+ "CheckAuthorization");
+ if (r < 0)
+ return r;
+
+ r = sd_bus_message_append(
+ request,
+ "(sa{sv})s",
+ "system-bus-name", 1, "name", "s", sender,
+ action);
+ if (r < 0)
+ return r;
+
+ r = bus_message_append_strv_key_value(request, details);
+ if (r < 0)
+ return r;
+
+ r = sd_bus_message_append(request, "us", 0, NULL);
+ if (r < 0)
+ return r;
+
+ r = sd_bus_call(call->bus, request, 0, ret_error, &reply);
+ if (r < 0) {
+ /* Treat no PK available as access denied */
+ if (bus_error_is_unknown_service(ret_error)) {
+ sd_bus_error_free(ret_error);
+ return -EACCES;
+ }
+
+ return r;
+ }
+
+ r = sd_bus_message_enter_container(reply, 'r', "bba{ss}");
+ if (r < 0)
+ return r;
+
+ r = sd_bus_message_read(reply, "bb", &authorized, &challenge);
+ if (r < 0)
+ return r;
+
+ if (authorized)
+ return 1;
+
+ if (_challenge) {
+ *_challenge = challenge;
+ return 0;
+ }
+ }
+#endif
+
+ return -EACCES;
+}
+
+#if ENABLE_POLKIT
+
+typedef struct AsyncPolkitQuery {
+ char *action;
+ char **details;
+
+ sd_bus_message *request, *reply;
+ sd_bus_slot *slot;
+
+ Hashmap *registry;
+ sd_event_source *defer_event_source;
+} AsyncPolkitQuery;
+
+static void async_polkit_query_free(AsyncPolkitQuery *q) {
+ if (!q)
+ return;
+
+ sd_bus_slot_unref(q->slot);
+
+ if (q->registry && q->request)
+ hashmap_remove(q->registry, q->request);
+
+ sd_bus_message_unref(q->request);
+ sd_bus_message_unref(q->reply);
+
+ free(q->action);
+ strv_free(q->details);
+
+ sd_event_source_disable_unref(q->defer_event_source);
+ free(q);
+}
+
+static int async_polkit_defer(sd_event_source *s, void *userdata) {
+ AsyncPolkitQuery *q = userdata;
+
+ assert(s);
+
+ /* This is called as idle event source after we processed the async polkit reply, hopefully after the
+ * method call we re-enqueued has been properly processed. */
+
+ async_polkit_query_free(q);
+ return 0;
+}
+
+static int async_polkit_callback(sd_bus_message *reply, void *userdata, sd_bus_error *error) {
+ AsyncPolkitQuery *q = userdata;
+ int r;
+
+ assert(reply);
+ assert(q);
+
+ assert(q->slot);
+ q->slot = sd_bus_slot_unref(q->slot);
+
+ assert(!q->reply);
+ q->reply = sd_bus_message_ref(reply);
+
+ /* Now, let's dispatch the original message a second time be re-enqueing. This will then traverse the
+ * whole message processing again, and thus re-validating and re-retrieving the "userdata" field
+ * again.
+ *
+ * We install an idle event loop event to clean-up the PolicyKit request data when we are idle again,
+ * i.e. after the second time the message is processed is complete. */
+
+ assert(!q->defer_event_source);
+ r = sd_event_add_defer(sd_bus_get_event(sd_bus_message_get_bus(reply)), &q->defer_event_source, async_polkit_defer, q);
+ if (r < 0)
+ goto fail;
+
+ r = sd_event_source_set_priority(q->defer_event_source, SD_EVENT_PRIORITY_IDLE);
+ if (r < 0)
+ goto fail;
+
+ r = sd_event_source_set_enabled(q->defer_event_source, SD_EVENT_ONESHOT);
+ if (r < 0)
+ goto fail;
+
+ r = sd_bus_message_rewind(q->request, true);
+ if (r < 0)
+ goto fail;
+
+ r = sd_bus_enqueue_for_read(sd_bus_message_get_bus(q->request), q->request);
+ if (r < 0)
+ goto fail;
+
+ return 1;
+
+fail:
+ log_debug_errno(r, "Processing asynchronous PolicyKit reply failed, ignoring: %m");
+ (void) sd_bus_reply_method_errno(q->request, r, NULL);
+ async_polkit_query_free(q);
+ return r;
+}
+
+#endif
+
+int bus_verify_polkit_async(
+ sd_bus_message *call,
+ int capability,
+ const char *action,
+ const char **details,
+ bool interactive,
+ uid_t good_user,
+ Hashmap **registry,
+ sd_bus_error *ret_error) {
+
+#if ENABLE_POLKIT
+ _cleanup_(sd_bus_message_unrefp) sd_bus_message *pk = NULL;
+ AsyncPolkitQuery *q;
+ int c;
+#endif
+ const char *sender;
+ int r;
+
+ assert(call);
+ assert(action);
+ assert(registry);
+
+ r = check_good_user(call, good_user);
+ if (r != 0)
+ return r;
+
+#if ENABLE_POLKIT
+ q = hashmap_get(*registry, call);
+ if (q) {
+ int authorized, challenge;
+
+ /* This is the second invocation of this function, and there's already a response from
+ * polkit, let's process it */
+ assert(q->reply);
+
+ /* If the operation we want to authenticate changed between the first and the second time,
+ * let's not use this authentication, it might be out of date as the object and context we
+ * operate on might have changed. */
+ if (!streq(q->action, action) ||
+ !strv_equal(q->details, (char**) details))
+ return -ESTALE;
+
+ if (sd_bus_message_is_method_error(q->reply, NULL)) {
+ const sd_bus_error *e;
+
+ e = sd_bus_message_get_error(q->reply);
+
+ /* Treat no PK available as access denied */
+ if (bus_error_is_unknown_service(e))
+ return -EACCES;
+
+ /* Copy error from polkit reply */
+ sd_bus_error_copy(ret_error, e);
+ return -sd_bus_error_get_errno(e);
+ }
+
+ r = sd_bus_message_enter_container(q->reply, 'r', "bba{ss}");
+ if (r >= 0)
+ r = sd_bus_message_read(q->reply, "bb", &authorized, &challenge);
+ if (r < 0)
+ return r;
+
+ if (authorized)
+ return 1;
+
+ if (challenge)
+ return sd_bus_error_set(ret_error, SD_BUS_ERROR_INTERACTIVE_AUTHORIZATION_REQUIRED, "Interactive authentication required.");
+
+ return -EACCES;
+ }
+#endif
+
+ r = sd_bus_query_sender_privilege(call, capability);
+ if (r < 0)
+ return r;
+ else if (r > 0)
+ return 1;
+
+ sender = sd_bus_message_get_sender(call);
+ if (!sender)
+ return -EBADMSG;
+
+#if ENABLE_POLKIT
+ c = sd_bus_message_get_allow_interactive_authorization(call);
+ if (c < 0)
+ return c;
+ if (c > 0)
+ interactive = true;
+
+ r = hashmap_ensure_allocated(registry, NULL);
+ if (r < 0)
+ return r;
+
+ r = sd_bus_message_new_method_call(
+ call->bus,
+ &pk,
+ "org.freedesktop.PolicyKit1",
+ "/org/freedesktop/PolicyKit1/Authority",
+ "org.freedesktop.PolicyKit1.Authority",
+ "CheckAuthorization");
+ if (r < 0)
+ return r;
+
+ r = sd_bus_message_append(
+ pk,
+ "(sa{sv})s",
+ "system-bus-name", 1, "name", "s", sender,
+ action);
+ if (r < 0)
+ return r;
+
+ r = bus_message_append_strv_key_value(pk, details);
+ if (r < 0)
+ return r;
+
+ r = sd_bus_message_append(pk, "us", interactive, NULL);
+ if (r < 0)
+ return r;
+
+ q = new(AsyncPolkitQuery, 1);
+ if (!q)
+ return -ENOMEM;
+
+ *q = (AsyncPolkitQuery) {
+ .request = sd_bus_message_ref(call),
+ };
+
+ q->action = strdup(action);
+ if (!q->action) {
+ async_polkit_query_free(q);
+ return -ENOMEM;
+ }
+
+ q->details = strv_copy((char**) details);
+ if (!q->details) {
+ async_polkit_query_free(q);
+ return -ENOMEM;
+ }
+
+ r = hashmap_put(*registry, call, q);
+ if (r < 0) {
+ async_polkit_query_free(q);
+ return r;
+ }
+
+ q->registry = *registry;
+
+ r = sd_bus_call_async(call->bus, &q->slot, pk, async_polkit_callback, q, 0);
+ if (r < 0) {
+ async_polkit_query_free(q);
+ return r;
+ }
+
+ return 0;
+#endif
+
+ return -EACCES;
+}
+
+void bus_verify_polkit_async_registry_free(Hashmap *registry) {
+#if ENABLE_POLKIT
+ hashmap_free_with_destructor(registry, async_polkit_query_free);
+#endif
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-26 04:40:24 +0000