From a1b7714b72fd2ba5dead01b465a9e37863051eff Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Mon, 24 Feb 2020 18:27:46 -0600 Subject: wireless: realtek: 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: Kalle Valo Link: https://lore.kernel.org/r/20200225002746.GA26789@embeddedor --- drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h | 2 +- drivers/net/wireless/realtek/rtlwifi/wifi.h | 6 +++--- drivers/net/wireless/realtek/rtw88/fw.h | 2 +- drivers/net/wireless/realtek/rtw88/main.h | 2 +- 4 files changed, 6 insertions(+), 6 deletions(-) (limited to 'drivers/net') diff --git a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h index 6598c8d786ea..440d164443bc 100644 --- a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h +++ b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h @@ -627,7 +627,7 @@ struct rtl8xxxu_firmware_header { u32 reserved4; u32 reserved5; - u8 data[0]; + u8 data[]; }; /* diff --git a/drivers/net/wireless/realtek/rtlwifi/wifi.h b/drivers/net/wireless/realtek/rtlwifi/wifi.h index 1cff9f07c9e9..13421cf2d201 100644 --- a/drivers/net/wireless/realtek/rtlwifi/wifi.h +++ b/drivers/net/wireless/realtek/rtlwifi/wifi.h @@ -1051,13 +1051,13 @@ struct rtl_hdr_3addr { u8 addr2[ETH_ALEN]; u8 addr3[ETH_ALEN]; __le16 seq_ctl; - u8 payload[0]; + u8 payload[]; } __packed; struct rtl_info_element { u8 id; u8 len; - u8 data[0]; + u8 data[]; } __packed; struct rtl_probe_rsp { @@ -1068,7 +1068,7 @@ struct rtl_probe_rsp { /*SSID, supported rates, FH params, DS params, * CF params, IBSS params, TIM (if beacon), RSN */ - struct rtl_info_element info_element[0]; + struct rtl_info_element info_element[]; } __packed; /*LED related.*/ diff --git a/drivers/net/wireless/realtek/rtw88/fw.h b/drivers/net/wireless/realtek/rtw88/fw.h index ccd27bd45775..414827800a5f 100644 --- a/drivers/net/wireless/realtek/rtw88/fw.h +++ b/drivers/net/wireless/realtek/rtw88/fw.h @@ -36,7 +36,7 @@ enum rtw_c2h_cmd_id_ext { struct rtw_c2h_cmd { u8 id; u8 seq; - u8 payload[0]; + u8 payload[]; } __packed; enum rtw_rsvd_packet_type { diff --git a/drivers/net/wireless/realtek/rtw88/main.h b/drivers/net/wireless/realtek/rtw88/main.h index 201ed8870754..c14a2b09b095 100644 --- a/drivers/net/wireless/realtek/rtw88/main.h +++ b/drivers/net/wireless/realtek/rtw88/main.h @@ -1640,7 +1640,7 @@ struct rtw_dev { struct rtw_wow_param wow; /* hci related data, must be last */ - u8 priv[0] __aligned(sizeof(void *)); + u8 priv[] __aligned(sizeof(void *)); }; #include "hci.h" -- cgit v1.2.3