From d974ad0524942882f489914013d08ab16d147170 Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Thu, 28 Aug 2014 12:42:03 +0200 Subject: [PATCH] bus: fix use-after-free in slot-release We must not access slot->floating after we possible dropped the last reference to it. Fix all callback-invocations to first check slot->floating and possible disconnect the slot, then release the last reference. --- src/libsystemd/sd-bus/sd-bus.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/src/libsystemd/sd-bus/sd-bus.c b/src/libsystemd/sd-bus/sd-bus.c index a204d6759..8caa40422 100644 --- a/src/libsystemd/sd-bus/sd-bus.c +++ b/src/libsystemd/sd-bus/sd-bus.c @@ -2107,7 +2107,7 @@ static int process_timeout(sd_bus *bus) { r = c->callback(bus, m, slot->userdata, &error_buffer); bus->current_userdata = NULL; bus->current_handler = NULL; - bus->current_slot = sd_bus_slot_unref(slot); + bus->current_slot = NULL; bus->current_message = NULL; if (slot->floating) { @@ -2115,6 +2115,8 @@ static int process_timeout(sd_bus *bus) { sd_bus_slot_unref(slot); } + sd_bus_slot_unref(slot); + return bus_maybe_reply_error(m, r, &error_buffer); } @@ -2203,13 +2205,15 @@ static int process_reply(sd_bus *bus, sd_bus_message *m) { r = c->callback(bus, m, slot->userdata, &error_buffer); bus->current_userdata = NULL; bus->current_handler = NULL; - bus->current_slot = sd_bus_slot_unref(slot); + bus->current_slot = NULL; if (slot->floating) { bus_slot_disconnect(slot); sd_bus_slot_unref(slot); } + sd_bus_slot_unref(slot); + return bus_maybe_reply_error(m, r, &error_buffer); } @@ -2529,7 +2533,7 @@ static int process_closing(sd_bus *bus, sd_bus_message **ret) { r = c->callback(bus, m, slot->userdata, &error_buffer); bus->current_userdata = NULL; bus->current_handler = NULL; - bus->current_slot = sd_bus_slot_unref(slot); + bus->current_slot = NULL; bus->current_message = NULL; if (slot->floating) { @@ -2537,6 +2541,8 @@ static int process_closing(sd_bus *bus, sd_bus_message **ret) { sd_bus_slot_unref(slot); } + sd_bus_slot_unref(slot); + return bus_maybe_reply_error(m, r, &error_buffer); } -- 2.30.2