[PATCH] staging: greybus: use after free in gb_audio_manager_remove_all()

Dan Carpenter dan.carpenter at oracle.com
Wed Feb 5 12:32:17 UTC 2020


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 at oracle.com>
---
 drivers/staging/greybus/audio_manager.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/staging/greybus/audio_manager.c b/drivers/staging/greybus/audio_manager.c
index 9b19ea9d3fa1..9a3f7c034ab4 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);
-- 
2.11.0



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