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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-02-17 13:59:41 -0600
committerDavid S. Miller <davem@davemloft.net>2020-02-17 19:05:05 -0800
commit9814428a44d63bf77831afdbb37b5f0aab7394c9 (patch)
treeaf810f1e12f4308013f42642ecf535263ed6cb16 /net/nfc
parentdc3cc347d2ce77da41f120a6162b40c6139df754 (diff)
NFC: digital: 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: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/nfc')
-rw-r--r--net/nfc/digital_dep.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/net/nfc/digital_dep.c b/net/nfc/digital_dep.c
index 65aaa9d7c813..304b1a9bb18a 100644
--- a/net/nfc/digital_dep.c
+++ b/net/nfc/digital_dep.c
@@ -71,7 +71,7 @@ struct digital_atr_req {
u8 bs;
u8 br;
u8 pp;
- u8 gb[0];
+ u8 gb[];
} __packed;
struct digital_atr_res {
@@ -83,7 +83,7 @@ struct digital_atr_res {
u8 br;
u8 to;
u8 pp;
- u8 gb[0];
+ u8 gb[];
} __packed;
struct digital_psl_req {