From 678e73bfd034f2d32dde5ffd1c6b63c456989541 Mon Sep 17 00:00:00 2001 From: Peter Benie Date: Fri, 23 Jun 2023 11:51:00 +0100 Subject: [PATCH] bus: Don't crash if bus_context_create_client_policy() fails If policy creation fails, we can't usefully leave a NULL policy in the BusConnectionData. If we did, the next attempt to reload policy would crash with a NULL dereference when we tried to unref it, or with an assertion failure. One situation in which we can legitimately fail to create a client policy is an out-of-memory condition. Another is if we are unable to look up a connection's supplementary groups with SO_PEERGROUPS, and also unable to look up the connection's uid's groups in the system user database, for example because it belongs to a user account that has been deleted (which is sysadmin error, but can happen, particularly in automated test systems) or because a service required by a Name Service Switch plugin has failed. Keeping the last known policy is consistent with what happens to all the connections that are after this one in iteration order: after we early-return, all of those connections retain their previous policies (which doesn't seem ideal either, but that's how this has always worked). [smcv: Add commit message] Co-authored-by: Simon McVittie Resolves: https://gitlab.freedesktop.org/dbus/dbus/-/issues/343 Conflict:NA Reference:https://gitlab.freedesktop.org/dbus/dbus/-/commit/678e73bfd034f2d32dde5ffd1c6b63c456989541 (cherry picked from commit 63522f2887878e6b9e40c9bb6742484679631ea9) --- bus/connection.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/bus/connection.c b/bus/connection.c index 215f0230..7a482e2b 100644 --- a/bus/connection.c +++ b/bus/connection.c @@ -1636,22 +1636,26 @@ bus_connections_reload_policy (BusConnections *connections, link; link = _dbus_list_get_next_link (&(connections->completed), link)) { + BusClientPolicy *policy; + connection = link->data; d = BUS_CONNECTION_DATA (connection); _dbus_assert (d != NULL); _dbus_assert (d->policy != NULL); - bus_client_policy_unref (d->policy); - d->policy = bus_context_create_client_policy (connections->context, - connection, - error); - if (d->policy == NULL) + policy = bus_context_create_client_policy (connections->context, + connection, + error); + if (policy == NULL) { _dbus_verbose ("Failed to create security policy for connection %p\n", connection); _DBUS_ASSERT_ERROR_IS_SET (error); return FALSE; } + + bus_client_policy_unref (d->policy); + d->policy = policy; } return TRUE; -- 2.27.0