diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-26 17:02:27 -0600 |
|---|---|---|
| committer | Marcel Holtmann <marcel@holtmann.org> | 2020-02-28 08:30:02 +0100 |
| commit | a7e454542bf8d57c75f59e7e7326c21db3d0bb3f (patch) | |
| tree | 668c086fa84b889902a48b81cb10b13ed42a2436 /include/net/bluetooth/l2cap.h | |
| parent | eed467b517e8c6987e3f227758ff3e67c889e17b (diff) | |
Bluetooth: Replace zero-length array with flexible-array member
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
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
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@embeddedor.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Diffstat (limited to 'include/net/bluetooth/l2cap.h')
| -rw-r--r-- | include/net/bluetooth/l2cap.h | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h index 093aedebdf0c..61dc731d5666 100644 --- a/include/net/bluetooth/l2cap.h +++ b/include/net/bluetooth/l2cap.h @@ -299,14 +299,14 @@ struct l2cap_conn_rsp { struct l2cap_conf_req { __le16 dcid; __le16 flags; - __u8 data[0]; + __u8 data[]; } __packed; struct l2cap_conf_rsp { __le16 scid; __le16 flags; __le16 result; - __u8 data[0]; + __u8 data[]; } __packed; #define L2CAP_CONF_SUCCESS 0x0000 @@ -322,7 +322,7 @@ struct l2cap_conf_rsp { struct l2cap_conf_opt { __u8 type; __u8 len; - __u8 val[0]; + __u8 val[]; } __packed; #define L2CAP_CONF_OPT_SIZE 2 @@ -392,7 +392,7 @@ struct l2cap_info_req { struct l2cap_info_rsp { __le16 type; __le16 result; - __u8 data[0]; + __u8 data[]; } __packed; struct l2cap_create_chan_req { |