From a7e454542bf8d57c75f59e7e7326c21db3d0bb3f Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Wed, 26 Feb 2020 17:02:27 -0600 Subject: 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 Signed-off-by: Marcel Holtmann --- drivers/bluetooth/btqca.h | 6 +++--- drivers/bluetooth/btrtl.h | 4 ++-- 2 files changed, 5 insertions(+), 5 deletions(-) (limited to 'drivers/bluetooth') 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) -- cgit v1.2.3