diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-27 02:02:27 +0300 |
|---|---|---|
| committer | Marcel Holtmann <marcel@holtmann.org> | 2020-02-28 10:30:02 +0300 |
| commit | a7e454542bf8d57c75f59e7e7326c21db3d0bb3f (patch) | |
| tree | 668c086fa84b889902a48b81cb10b13ed42a2436 /net/bluetooth/a2mp.h | |
| parent | eed467b517e8c6987e3f227758ff3e67c889e17b (diff) | |
| download | linux-a7e454542bf8d57c75f59e7e7326c21db3d0bb3f.tar.xz | |
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 'net/bluetooth/a2mp.h')
| -rw-r--r-- | net/bluetooth/a2mp.h | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/net/bluetooth/a2mp.h b/net/bluetooth/a2mp.h index 0029d5119be6..2fd253a61a2a 100644 --- a/net/bluetooth/a2mp.h +++ b/net/bluetooth/a2mp.h @@ -36,14 +36,14 @@ struct a2mp_cmd { __u8 code; __u8 ident; __le16 len; - __u8 data[0]; + __u8 data[]; } __packed; /* A2MP command codes */ #define A2MP_COMMAND_REJ 0x01 struct a2mp_cmd_rej { __le16 reason; - __u8 data[0]; + __u8 data[]; } __packed; #define A2MP_DISCOVER_REQ 0x02 @@ -62,7 +62,7 @@ struct a2mp_cl { struct a2mp_discov_rsp { __le16 mtu; __le16 ext_feat; - struct a2mp_cl cl[0]; + struct a2mp_cl cl[]; } __packed; #define A2MP_CHANGE_NOTIFY 0x04 @@ -93,7 +93,7 @@ struct a2mp_amp_assoc_req { struct a2mp_amp_assoc_rsp { __u8 id; __u8 status; - __u8 amp_assoc[0]; + __u8 amp_assoc[]; } __packed; #define A2MP_CREATEPHYSLINK_REQ 0x0A @@ -101,7 +101,7 @@ struct a2mp_amp_assoc_rsp { struct a2mp_physlink_req { __u8 local_id; __u8 remote_id; - __u8 amp_assoc[0]; + __u8 amp_assoc[]; } __packed; #define A2MP_CREATEPHYSLINK_RSP 0x0B |