From da60fbe7ef942d64b4d80e99cc9b0205db5964b9 Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Wed, 26 Feb 2020 15:20:00 -0600 Subject: NFC: 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: David S. Miller --- drivers/nfc/st21nfca/dep.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/nfc/st21nfca') diff --git a/drivers/nfc/st21nfca/dep.c b/drivers/nfc/st21nfca/dep.c index 60acdfd1cb8c..a1d69f9b2d4a 100644 --- a/drivers/nfc/st21nfca/dep.c +++ b/drivers/nfc/st21nfca/dep.c @@ -66,7 +66,7 @@ struct st21nfca_atr_req { u8 bsi; u8 bri; u8 ppi; - u8 gbi[0]; + u8 gbi[]; } __packed; struct st21nfca_atr_res { @@ -79,7 +79,7 @@ struct st21nfca_atr_res { u8 bri; u8 to; u8 ppi; - u8 gbi[0]; + u8 gbi[]; } __packed; struct st21nfca_psl_req { -- cgit v1.2.3