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@xxxxxxxxxxxxxx>
---
drivers/bluetooth/btqca.h | 6 +++---
drivers/bluetooth/btrtl.h | 4 ++--
include/net/bluetooth/hci.h | 30 +++++++++++++++---------------
include/net/bluetooth/hci_sock.h | 6 +++---
include/net/bluetooth/l2cap.h | 8 ++++----
include/net/bluetooth/rfcomm.h | 2 +-
net/bluetooth/a2mp.h | 10 +++++-----
net/bluetooth/bnep/bnep.h | 6 +++---
8 files changed, 36 insertions(+), 36 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)
diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index 6293bdd7d862..d878bf8dce20 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -935,7 +935,7 @@ struct hci_cp_sniff_subrate {
struct hci_cp_set_event_flt {
__u8 flt_type;
__u8 cond_type;
- __u8 condition[0];
+ __u8 condition[];
} __packed;
/* Filter types */
@@ -1335,7 +1335,7 @@ struct hci_rp_read_local_amp_assoc {
__u8 status;
__u8 phy_handle;
__le16 rem_len;
- __u8 frag[0];
+ __u8 frag[];
} __packed;
#define HCI_OP_WRITE_REMOTE_AMP_ASSOC 0x140b
@@ -1343,7 +1343,7 @@ struct hci_cp_write_remote_amp_assoc {
__u8 phy_handle;
__le16 len_so_far;
__le16 rem_len;
- __u8 frag[0];
+ __u8 frag[];
} __packed;
struct hci_rp_write_remote_amp_assoc {
__u8 status;
@@ -1613,7 +1613,7 @@ struct hci_cp_le_set_ext_scan_params {
__u8 own_addr_type;
__u8 filter_policy;
__u8 scanning_phys;
- __u8 data[0];
+ __u8 data[];
} __packed;
#define LE_SCAN_PHY_1M 0x01
@@ -1641,7 +1641,7 @@ struct hci_cp_le_ext_create_conn {
__u8 peer_addr_type;
bdaddr_t peer_addr;
__u8 phys;
- __u8 data[0];
+ __u8 data[];
} __packed;
struct hci_cp_le_ext_conn_param {
@@ -1693,7 +1693,7 @@ struct hci_rp_le_set_ext_adv_params {
struct hci_cp_le_set_ext_adv_enable {
__u8 enable;
__u8 num_of_sets;
- __u8 data[0];
+ __u8 data[];
} __packed;
struct hci_cp_ext_adv_set {
@@ -1775,14 +1775,14 @@ struct hci_cp_le_set_cig_params {
__le16 m_latency;
__le16 s_latency;
__u8 num_cis;
- struct hci_cis_params cis[0];
+ struct hci_cis_params cis[];
} __packed;
struct hci_rp_le_set_cig_params {
__u8 status;
__u8 cig_id;
__u8 num_handles;
- __le16 handle[0];
+ __le16 handle[];
} __packed;
#define HCI_OP_LE_CREATE_CIS 0x2064
@@ -1793,7 +1793,7 @@ struct hci_cis {
struct hci_cp_le_create_cis {
__u8 num_cis;
- struct hci_cis cis[0];
+ struct hci_cis cis[];
} __packed;
#define HCI_OP_LE_REMOVE_CIG 0x2065
@@ -1937,7 +1937,7 @@ struct hci_comp_pkts_info {
struct hci_ev_num_comp_pkts {
__u8 num_hndl;
- struct hci_comp_pkts_info handles[0];
+ struct hci_comp_pkts_info handles[];
} __packed;
#define HCI_EV_MODE_CHANGE 0x14
@@ -2170,7 +2170,7 @@ struct hci_comp_blocks_info {
struct hci_ev_num_comp_blocks {
__le16 num_blocks;
__u8 num_hndl;
- struct hci_comp_blocks_info handles[0];
+ struct hci_comp_blocks_info handles[];
} __packed;
#define HCI_EV_SYNC_TRAIN_COMPLETE 0x4F
@@ -2226,7 +2226,7 @@ struct hci_ev_le_advertising_info {
__u8 bdaddr_type;
bdaddr_t bdaddr;
__u8 length;
- __u8 data[0];
+ __u8 data[];
} __packed;
#define HCI_EV_LE_CONN_UPDATE_COMPLETE 0x03
@@ -2302,7 +2302,7 @@ struct hci_ev_le_ext_adv_report {
__u8 direct_addr_type;
bdaddr_t direct_addr;
__u8 length;
- __u8 data[0];
+ __u8 data[];
} __packed;
#define HCI_EV_LE_ENHANCED_CONN_COMPLETE 0x0a
@@ -2362,7 +2362,7 @@ struct hci_evt_le_cis_req {
#define HCI_EV_STACK_INTERNAL 0xfd
struct hci_ev_stack_internal {
__u16 type;
- __u8 data[0];
+ __u8 data[];
} __packed;
#define HCI_EV_SI_DEVICE 0x01
@@ -2409,7 +2409,7 @@ struct hci_sco_hdr {
struct hci_iso_hdr {
__le16 handle;
__le16 dlen;
- __u8 data[0];
+ __u8 data[];
} __packed;
/* ISO data packet status flags */
diff --git a/include/net/bluetooth/hci_sock.h b/include/net/bluetooth/hci_sock.h
index 8e9138acdae1..9352bb1bf34c 100644
--- a/include/net/bluetooth/hci_sock.h
+++ b/include/net/bluetooth/hci_sock.h
@@ -144,19 +144,19 @@ struct hci_dev_req {
struct hci_dev_list_req {
__u16 dev_num;
- struct hci_dev_req dev_req[0]; /* hci_dev_req structures */
+ struct hci_dev_req dev_req[]; /* hci_dev_req structures */
};
struct hci_conn_list_req {
__u16 dev_id;
__u16 conn_num;
- struct hci_conn_info conn_info[0];
+ struct hci_conn_info conn_info[];
};
struct hci_conn_info_req {
bdaddr_t bdaddr;
__u8 type;
- struct hci_conn_info conn_info[0];
+ struct hci_conn_info conn_info[];
};
struct hci_auth_info_req {
diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index 093aedebdf0c..61dc731d5666 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -299,14 +299,14 @@ struct l2cap_conn_rsp {
struct l2cap_conf_req {
__le16 dcid;
__le16 flags;
- __u8 data[0];
+ __u8 data[];
} __packed;
struct l2cap_conf_rsp {
__le16 scid;
__le16 flags;
__le16 result;
- __u8 data[0];
+ __u8 data[];
} __packed;
#define L2CAP_CONF_SUCCESS 0x0000
@@ -322,7 +322,7 @@ struct l2cap_conf_rsp {
struct l2cap_conf_opt {
__u8 type;
__u8 len;
- __u8 val[0];
+ __u8 val[];
} __packed;
#define L2CAP_CONF_OPT_SIZE 2
@@ -392,7 +392,7 @@ struct l2cap_info_req {
struct l2cap_info_rsp {
__le16 type;
__le16 result;
- __u8 data[0];
+ __u8 data[];
} __packed;
struct l2cap_create_chan_req {
diff --git a/include/net/bluetooth/rfcomm.h b/include/net/bluetooth/rfcomm.h
index 8d65d2a0b9b4..99d26879b02a 100644
--- a/include/net/bluetooth/rfcomm.h
+++ b/include/net/bluetooth/rfcomm.h
@@ -355,7 +355,7 @@ struct rfcomm_dev_info {
struct rfcomm_dev_list_req {
u16 dev_num;
- struct rfcomm_dev_info dev_info[0];
+ struct rfcomm_dev_info dev_info[];
};
int rfcomm_dev_ioctl(struct sock *sk, unsigned int cmd, void __user *arg);
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
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 */
--
2.25.0
