diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-03-02 06:07:42 -0600 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-03-02 11:16:28 -0800 |
| commit | 48b77df665e0a268b61a795208e647b6b7bb7e00 (patch) | |
| tree | f429ccb5cb0d1496f79ded87fad1aeabf7d1fc0e | |
| parent | 6e68f499e93429e521af40cb25129f27c6c80a10 (diff) | |
net: inet_sock: 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/inet_sock.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h index 34c4436fd18f..a7ce00af6c44 100644 --- a/include/net/inet_sock.h +++ b/include/net/inet_sock.h @@ -52,7 +52,7 @@ struct ip_options { unsigned char router_alert; unsigned char cipso; unsigned char __pad2; - unsigned char __data[0]; + unsigned char __data[]; }; struct ip_options_rcu { |