diff options
author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-28 16:30:45 +0300 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2020-02-28 23:08:37 +0300 |
commit | af71b090c88c12816d43514190790de919921cea (patch) | |
tree | 12503a8b35ac1bfd3e186b704fab8406ff34361a /net/l2tp | |
parent | 680a93166e80e43e3ff85be06005c5cfa492d852 (diff) |
l2tp: 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]
Lastly, fix the following checkpatch warning:
CHECK: Prefer kernel type 'u8' over 'uint8_t'
#50: FILE: net/l2tp/l2tp_core.h:119:
+ uint8_t priv[]; /* private data */
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/l2tp')
-rw-r--r-- | net/l2tp/l2tp_core.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h index 2db3d50d10a4..10cf7c3dcbb3 100644 --- a/net/l2tp/l2tp_core.h +++ b/net/l2tp/l2tp_core.h @@ -116,7 +116,7 @@ struct l2tp_session { void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len); void (*session_close)(struct l2tp_session *session); void (*show)(struct seq_file *m, void *priv); - uint8_t priv[0]; /* private data */ + u8 priv[]; /* private data */ }; /* Describes the tunnel. It contains info to track all the associated |