if (!policy)
return 0;
+ /*
+ * dbus-1 distinguishes expected and non-expected replies by tracking
+ * method-calls and timeouts. By default, DENY rules are *NEVER* applied
+ * on expected replies, unless explicitly specified. But we dont track
+ * method-calls, thus, we cannot know whether a reply is expected.
+ * Fortunately, the kdbus forbids non-expected replies, so we can safely
+ * ignore any policy on those and let the kernel deal with it.
+ *
+ * TODO: To be correct, we should only ignore policy-tags that are
+ * applied on non-expected replies. However, so far we don't parse those
+ * tags so we let everything pass. I haven't seen a DENY policy tag on
+ * expected-replies, ever, so don't bother..
+ */
+ if (m->reply_cookie > 0)
+ return 0;
+
if (from->is_kernel) {
uid_t sender_uid = UID_INVALID;
gid_t sender_gid = GID_INVALID;
(void) sd_bus_creds_get_uid(&m->creds, &sender_uid);
(void) sd_bus_creds_get_gid(&m->creds, &sender_gid);
+ if (sender_uid == UID_INVALID || sender_gid == GID_INVALID) {
+ _cleanup_bus_creds_unref_ sd_bus_creds *sender_creds = NULL;
+
+ /* If the message came from another legacy
+ * client, then the message creds will be
+ * missing, simply because on legacy clients
+ * per-message creds were unknown. In this
+ * case, query the creds of the peer
+ * instead. */
+
+ r = bus_get_name_creds_kdbus(from, m->sender, SD_BUS_CREDS_UID|SD_BUS_CREDS_GID, true, &sender_creds);
+ if (r < 0)
+ return handle_policy_error(m, r);
+
+ (void) sd_bus_creds_get_uid(sender_creds, &sender_uid);
+ (void) sd_bus_creds_get_gid(sender_creds, &sender_gid);
+ }
+
/* First check whether the sender can send the message to our name */
if (set_isempty(owned_names)) {
if (policy_check_send(policy, sender_uid, sender_gid, m->header->type, NULL, m->path, m->interface, m->member))
_cleanup_free_ char *peersec = NULL;
Policy policy_buffer = {}, *policy = NULL;
_cleanup_set_free_free_ Set *owned_names = NULL;
+ uid_t original_uid;
log_set_target(LOG_TARGET_JOURNAL_OR_KMSG);
log_parse_environment();
goto finish;
}
+ original_uid = getuid();
+
is_unix =
sd_is_socket(in_fd, AF_UNIX, 0, 0) > 0 &&
sd_is_socket(out_fd, AF_UNIX, 0, 0) > 0;
policy = &policy_buffer;
/* policy_dump(policy); */
- if (!policy_check_hello(policy, ucred.uid, ucred.gid)) {
+ if (ucred.uid == original_uid)
+ log_debug("Permitting access, since bus owner matches bus client.");
+ else if (policy_check_hello(policy, ucred.uid, ucred.gid))
+ log_debug("Permitting access due to XML policy.");
+ else {
r = log_error_errno(EPERM, "Policy denied connection.");
goto finish;
}
if (!processed) {
k = sd_bus_send(b, m, NULL);
if (k < 0) {
- if (k == -ECONNRESET)
+ if (k == -ECONNRESET) {
r = 0;
- else {
+ goto finish;
+ } else if (k == -EPERM && m->reply_cookie > 0) {
+ /* If the peer tries to send a reply and it is rejected with EPERM
+ * by the kernel, we ignore the error. This catches cases where the
+ * original method-call didn't had EXPECT_REPLY set, but the proxy-peer
+ * still sends a reply. This is allowed in dbus1, but not in kdbus. We
+ * don't want to track reply-windows in the proxy, so we simply ignore
+ * EPERM for all replies. The only downside is, that callers are no
+ * longer notified if their replies are dropped. However, this is
+ * equivalent to the caller's timeout to expire, so this should be
+ * acceptable. Nobody sane sends replies without a matching method-call,
+ * so nobody should care. */
+ r = 1;
+ } else {
r = k;
log_error_errno(r, "Failed to send message to client: %m");
+ goto finish;
}
-
- goto finish;
} else
r = 1;
}
k = sd_bus_send(a, m, NULL);
if (k < 0) {
- if (k == -EREMCHG)
+ if (k == -EREMCHG) {
/* The name database changed since the policy check, hence let's check again */
continue;
- else if (k == -ECONNRESET)
+ } else if (k == -ECONNRESET) {
r = 0;
- else {
+ goto finish;
+ } else if (k == -EPERM && m->reply_cookie > 0) {
+ /* see above why EPERM is ignored for replies */
+ r = 1;
+ } else {
r = k;
log_error_errno(r, "Failed to send message to bus: %m");
+ goto finish;
}
-
- goto finish;
} else
r = 1;
~ianmdlvl / elogind.git / blobdiff