From bc1d50a1a485981784158c62b67c0268fdec5a10 Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Mon, 24 Feb 2020 19:11:51 -0600 Subject: hostap: 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/20200225011151.GA30675@embeddedor --- drivers/net/wireless/intersil/hostap/hostap_common.h | 2 +- drivers/net/wireless/intersil/hostap/hostap_wlan.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/net/wireless/intersil/hostap') diff --git a/drivers/net/wireless/intersil/hostap/hostap_common.h b/drivers/net/wireless/intersil/hostap/hostap_common.h index 22543538239b..dd29a8e8d349 100644 --- a/drivers/net/wireless/intersil/hostap/hostap_common.h +++ b/drivers/net/wireless/intersil/hostap/hostap_common.h @@ -322,7 +322,7 @@ struct prism2_download_param { u32 addr; /* wlan card address */ u32 len; void __user *ptr; /* pointer to data in user space */ - } data[0]; + } data[]; }; #define PRISM2_MAX_DOWNLOAD_AREA_LEN 131072 diff --git a/drivers/net/wireless/intersil/hostap/hostap_wlan.h b/drivers/net/wireless/intersil/hostap/hostap_wlan.h index 487883fbb58c..dd2603d9b5d3 100644 --- a/drivers/net/wireless/intersil/hostap/hostap_wlan.h +++ b/drivers/net/wireless/intersil/hostap/hostap_wlan.h @@ -615,7 +615,7 @@ struct prism2_download_data { u32 addr; /* wlan card address */ u32 len; u8 *data; /* allocated data */ - } data[0]; + } data[]; }; -- cgit v1.2.3