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>

diff --git a/drivers/bluetooth/btqca.h b/drivers/bluetooth/btqca.h
index f5795b1a3779cccdb92cd8f228a46a71a613e87c..e16a4d650597d74db65809087188f097af479073 100644 (file)
--- 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 10ad40c3e42c23d8f205496702827e73e1f9581a..2a582682136d6167fcc7d1b1666fb7023bd62020 100644 (file)
--- 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 6293bdd7d862f9aa9c032a6729492fbd081dda66..d878bf8dce2061f80ce745e99dfa84b9679334b0 100644 (file)
--- 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 8e9138acdae14fd74478761ae74dd9783c310ff6..9352bb1bf34cb13628c3d33f9c0c3fb0c42ed1c2 100644 (file)
--- 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 093aedebdf0ca03f1f270fa77a523d8309229c84..61dc731d5666f9b6c30cc36f1e7f633384078ae3 100644 (file)
--- 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 8d65d2a0b9b46cbc2ecaa010613955c51fdc0955..99d26879b02a53a10aee3c36d414abc0726cbeb0 100644 (file)
--- 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 0029d5119be6b7fde0faa485b8571a0c599c592c..2fd253a61a2a16f22e6dc7b3af8a46c6509dd418 100644 (file)
--- 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 24f18b1339596cebf544b2ea9275fb126bdd3d44..9680473ed7efa0da9eaebb4a0e98e1892bf29dd1 100644 (file)
--- 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 */