diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-28 18:50:23 -0600 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-02-29 21:52:20 -0800 |
| commit | e8316026d538873f60f41dab4caaa493a21684b0 (patch) | |
| tree | c5b67548a7f79c2e85fa41eae422c4c0014161fd | |
| parent | 207644f5138fb8e14debaa22f72adaa78c6a08cc (diff) | |
net: lwtunnel: 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-- | include/net/lwtunnel.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/net/lwtunnel.h b/include/net/lwtunnel.h index 5d6c5b1fc695..b5e6edf74b70 100644 --- a/include/net/lwtunnel.h +++ b/include/net/lwtunnel.h @@ -30,7 +30,7 @@ struct lwtunnel_state { int (*orig_output)(struct net *net, struct sock *sk, struct sk_buff *skb); int (*orig_input)(struct sk_buff *); struct rcu_head rcu; - __u8 data[0]; + __u8 data[]; }; struct lwtunnel_encap_ops { |