diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-03-02 06:00:48 -0600 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-03-02 11:16:27 -0800 |
| commit | 2e83abdcb30e3881e9569fd8f4a600beef6cfadc (patch) | |
| tree | 5d0bb3443b5dc1c7b9df393fd4d94bb11b203b4a /include | |
| parent | bb4cf02d4c74f0db60f58c406ddfdfed16d14f84 (diff) | |
| download | linux-2e83abdcb30e3881e9569fd8f4a600beef6cfadc.tar.bz2 | |
net: mip6: 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 'include')
| -rw-r--r-- | include/net/mip6.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/net/mip6.h b/include/net/mip6.h index f1c28971c362..67cd7e50804c 100644 --- a/include/net/mip6.h +++ b/include/net/mip6.h @@ -25,7 +25,7 @@ struct ip6_mh { __u8 ip6mh_reserved; __u16 ip6mh_cksum; /* Followed by type specific messages */ - __u8 data[0]; + __u8 data[]; } __packed; #define IP6_MH_TYPE_BRR 0 /* Binding Refresh Request */ |