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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 /drivers/bluetooth
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 'drivers/bluetooth')
-rw-r--r--drivers/bluetooth/btqca.h6
-rw-r--r--drivers/bluetooth/btrtl.h4
2 files changed, 5 insertions, 5 deletions
diff --git a/drivers/bluetooth/btqca.h b/drivers/bluetooth/btqca.h
index f5795b1a3779..e16a4d650597 100644
--- a/drivers/bluetooth/btqca.h
+++ b/drivers/bluetooth/btqca.h
@@ -79,7 +79,7 @@ struct qca_fw_config {
struct edl_event_hdr {
__u8 cresp;
__u8 rtype;
- __u8 data[0];
+ __u8 data[];
} __packed;
struct qca_btsoc_version {
@@ -112,12 +112,12 @@ struct tlv_type_nvm {
__le16 tag_len;
__le32 reserve1;
__le32 reserve2;
- __u8 data[0];
+ __u8 data[];
} __packed;
struct tlv_type_hdr {
__le32 type_len;
- __u8 data[0];
+ __u8 data[];
} __packed;
enum qca_btsoc_type {
diff --git a/drivers/bluetooth/btrtl.h b/drivers/bluetooth/btrtl.h
index 10ad40c3e42c..2a582682136d 100644
--- a/drivers/bluetooth/btrtl.h
+++ b/drivers/bluetooth/btrtl.h
@@ -38,13 +38,13 @@ struct rtl_epatch_header {
struct rtl_vendor_config_entry {
__le16 offset;
__u8 len;
- __u8 data[0];
+ __u8 data[];
} __packed;
struct rtl_vendor_config {
__le32 signature;
__le16 total_len;
- struct rtl_vendor_config_entry entry[0];
+ struct rtl_vendor_config_entry entry[];
} __packed;
#if IS_ENABLED(CONFIG_BT_RTL)