From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Wed, 5 Feb 2020 12:32:17 +0000 (+0300)
Subject: staging: greybus: use after free in gb_audio_manager_remove_all()
X-Git-Tag: v5.5.7~28
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=a9f659d837fedca7518b6968e26133fe5af40935;p=users%2Fdwmw2%2Flinux.git

staging: greybus: use after free in gb_audio_manager_remove_all()

commit b7db58105b80fa9232719c8329b995b3addfab55 upstream.

When we call kobject_put() and it's the last reference to the kobject
then it calls gb_audio_module_release() and frees module.  We dereference
"module" on the next line which is a use after free.

Fixes: c77f85bbc91a ("greybus: audio: Fix incorrect counting of 'ida'")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Vaibhav Agarwal <vaibhav.sr@gmail.com>
Link: https://lore.kernel.org/r/20200205123217.jreendkyxulqsool@kili.mountain
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/staging/greybus/audio_manager.c b/drivers/staging/greybus/audio_manager.c
index 9b19ea9d3fa14..9a3f7c034ab49 100644
--- a/drivers/staging/greybus/audio_manager.c
+++ b/drivers/staging/greybus/audio_manager.c
@@ -92,8 +92,8 @@ void gb_audio_manager_remove_all(void)
 
 	list_for_each_entry_safe(module, next, &modules_list, list) {
 		list_del(&module->list);
-		kobject_put(&module->kobj);
 		ida_simple_remove(&module_id, module->id);
+		kobject_put(&module->kobj);
 	}
 
 	is_empty = list_empty(&modules_list);