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| 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 /net/bluetooth/bnep | |
| parent | Bluetooth: fix passkey uninitialized when used (diff) | |
| download | linux-dev-a7e454542bf8d57c75f59e7e7326c21db3d0bb3f.tar.xz linux-dev-a7e454542bf8d57c75f59e7e7326c21db3d0bb3f.zip | |
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/bnep')
| -rw-r--r-- | net/bluetooth/bnep/bnep.h | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/net/bluetooth/bnep/bnep.h b/net/bluetooth/bnep/bnep.h index 24f18b133959..9680473ed7ef 100644 --- a/net/bluetooth/bnep/bnep.h +++ b/net/bluetooth/bnep/bnep.h @@ -74,14 +74,14 @@ struct bnep_setup_conn_req { __u8 type; __u8 ctrl; __u8 uuid_size; - __u8 service[0]; + __u8 service[]; } __packed; struct bnep_set_filter_req { __u8 type; __u8 ctrl; __be16 len; - __u8 list[0]; + __u8 list[]; } __packed; struct bnep_control_rsp { @@ -93,7 +93,7 @@ struct bnep_control_rsp { struct bnep_ext_hdr { __u8 type; __u8 len; - __u8 data[0]; + __u8 data[]; } __packed; /* BNEP ioctl defines */ |