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| author |   Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-17 13:59:41 -0600 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2020-02-17 19:05:05 -0800 |
| commit | 9814428a44d63bf77831afdbb37b5f0aab7394c9 (patch) | |
| tree | af810f1e12f4308013f42642ecf535263ed6cb16 | |
| parent | net: usb: cdc-phonet: Replace zero-length array with flexible-array member (diff) | |
| download | linux-dev-9814428a44d63bf77831afdbb37b5f0aab7394c9.tar.xz linux-dev-9814428a44d63bf77831afdbb37b5f0aab7394c9.zip | |
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>
| -rw-r--r-- | net/nfc/digital_dep.c | 4 |
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 { |