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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-02-27 02:02:27 +0300
committerMarcel Holtmann <marcel@holtmann.org>2020-02-28 10:30:02 +0300
commita7e454542bf8d57c75f59e7e7326c21db3d0bb3f (patch)
tree668c086fa84b889902a48b81cb10b13ed42a2436 /net/bluetooth/a2mp.h
parenteed467b517e8c6987e3f227758ff3e67c889e17b (diff)
downloadlinux-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.h10
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