wireless: ti: 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: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200225003408.GA28675@embeddedor

diff --git a/drivers/net/wireless/ti/wl1251/cmd.h b/drivers/net/wireless/ti/wl1251/cmd.h
index 1c1a591c60559a972bd6d01943f224fe9dfc4b8e..e5874186f9d7570827da539a860bdd9024b3a701 100644 (file)
--- a/drivers/net/wireless/ti/wl1251/cmd.h
+++ b/drivers/net/wireless/ti/wl1251/cmd.h
@@ -90,7 +90,7 @@ struct wl1251_cmd_header {
        u16 id;
        u16 status;
        /* payload */
-       u8 data[0];
+       u8 data[];
 } __packed;
 
 struct  wl1251_command {
@@ -281,7 +281,7 @@ struct wl1251_cmd_packet_template {
        struct wl1251_cmd_header header;
 
        __le16 size;
-       u8 data[0];
+       u8 data[];
 } __packed;
 
 #define TIM_ELE_ID    5

diff --git a/drivers/net/wireless/ti/wl1251/wl12xx_80211.h b/drivers/net/wireless/ti/wl1251/wl12xx_80211.h
index 7fabe702c4cc3f19a96b3422c84cf327c852c6b9..7e28fe435b433d842d9663bedca6f36786f04578 100644 (file)
--- a/drivers/net/wireless/ti/wl1251/wl12xx_80211.h
+++ b/drivers/net/wireless/ti/wl1251/wl12xx_80211.h
@@ -65,7 +65,7 @@ struct ieee80211_header {
        u8 sa[ETH_ALEN];
        u8 bssid[ETH_ALEN];
        __le16 seq_ctl;
-       u8 payload[0];
+       u8 payload[];
 } __packed;
 
 struct wl12xx_ie_header {

diff --git a/drivers/net/wireless/ti/wlcore/acx.h b/drivers/net/wireless/ti/wlcore/acx.h
index a265fba0cb4c49a6203f4652187ad0edabc25328..c725f5855c134fc1ddd1523a0fd525a4937ec89a 100644 (file)
--- a/drivers/net/wireless/ti/wlcore/acx.h
+++ b/drivers/net/wireless/ti/wlcore/acx.h
@@ -938,7 +938,7 @@ struct acx_rx_filter_cfg {
        u8 action;
 
        u8 num_fields;
-       u8 fields[0];
+       u8 fields[];
 } __packed;
 
 struct acx_roaming_stats {

diff --git a/drivers/net/wireless/ti/wlcore/boot.h b/drivers/net/wireless/ti/wlcore/boot.h
index 14b367e98dce54fe9ba04aad802f03a2d523b64c..24a2dfcb41ea4f75fa62d75fc11e117e50c2c192 100644 (file)
--- a/drivers/net/wireless/ti/wlcore/boot.h
+++ b/drivers/net/wireless/ti/wlcore/boot.h
@@ -26,7 +26,7 @@ struct wl1271_static_data {
        u8 fw_version[WL1271_FW_VERSION_MAX_LEN];
        u32 hw_version;
        u8 tx_power_table[WL1271_NO_SUBBANDS][WL1271_NO_POWER_LEVELS];
-       u8 priv[0];
+       u8 priv[];
 };
 
 /* number of times we try to read the INIT interrupt */

diff --git a/drivers/net/wireless/ti/wlcore/cmd.h b/drivers/net/wireless/ti/wlcore/cmd.h
index bfad7b5a1ac6c8e3a32e1acb62af39f5c9a9785f..f2609d5b6bf717f9d1600d9256058b43f84158b8 100644 (file)
--- a/drivers/net/wireless/ti/wlcore/cmd.h
+++ b/drivers/net/wireless/ti/wlcore/cmd.h
@@ -209,7 +209,7 @@ struct wl1271_cmd_header {
        __le16 id;
        __le16 status;
        /* payload */
-       u8 data[0];
+       u8 data[];
 } __packed;
 
 #define WL1271_CMD_MAX_PARAMS 572

diff --git a/drivers/net/wireless/ti/wlcore/conf.h b/drivers/net/wireless/ti/wlcore/conf.h
index 6116383ee2486d921788d9c801444ab79e0c0ffa..31be425f2332da084c41fb424c46e55f82e914d0 100644 (file)
--- a/drivers/net/wireless/ti/wlcore/conf.h
+++ b/drivers/net/wireless/ti/wlcore/conf.h
@@ -1150,7 +1150,7 @@ struct wlcore_conf {
 struct wlcore_conf_file {
        struct wlcore_conf_header header;
        struct wlcore_conf core;
-       u8 priv[0];
+       u8 priv[];
 } __packed;
 
 #endif

diff --git a/drivers/net/wireless/ti/wlcore/wl12xx_80211.h b/drivers/net/wireless/ti/wlcore/wl12xx_80211.h
index 181be725eff88e2dc9ba5678d1bdbe002efcb284..1dd7ecc11f862f24225c9041880711328b59c992 100644 (file)
--- a/drivers/net/wireless/ti/wlcore/wl12xx_80211.h
+++ b/drivers/net/wireless/ti/wlcore/wl12xx_80211.h
@@ -66,7 +66,7 @@ struct ieee80211_header {
        u8 sa[ETH_ALEN];
        u8 bssid[ETH_ALEN];
        __le16 seq_ctl;
-       u8 payload[0];
+       u8 payload[];
 } __packed;
 
 struct wl12xx_ie_header {