The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertenly introduced[3] to the codebase from now on.
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo(a)embeddedor.com>
---
drivers/staging/greybus/raw.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/staging/greybus/raw.c b/drivers/staging/greybus/raw.c
index 838acbe84ca0..2b301b2aa107 100644
--- a/drivers/staging/greybus/raw.c
+++ b/drivers/staging/greybus/raw.c
@@ -30,7 +30,7 @@ struct gb_raw {
struct raw_data {
struct list_head entry;
u32 len;
- u8 data[0];
+ u8 data[];
};
static struct class *raw_class;
--
2.25.0
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(a)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