diff options
author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-20 16:59:14 +0300 |
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committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2020-03-15 17:20:16 +0300 |
commit | 6daf14140129d30207ed6a0a69851fa6a3636bda (patch) | |
tree | 43f5f5d662db9cfc241ba1c848f17694b95a16ff /include/linux/netfilter_ipv6/ip6_tables.h | |
parent | eb9d7af3b7bd6d1b51c6522de53a5bf9c57e81db (diff) | |
download | linux-6daf14140129d30207ed6a0a69851fa6a3636bda.tar.xz |
netfilter: 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 checkpatch.pl warning
WARNING: __aligned(size) is preferred over __attribute__((aligned(size)))
in net/bridge/netfilter/ebtables.c
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: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'include/linux/netfilter_ipv6/ip6_tables.h')
-rw-r--r-- | include/linux/netfilter_ipv6/ip6_tables.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/netfilter_ipv6/ip6_tables.h b/include/linux/netfilter_ipv6/ip6_tables.h index 78ab959c4575..8225f7821a29 100644 --- a/include/linux/netfilter_ipv6/ip6_tables.h +++ b/include/linux/netfilter_ipv6/ip6_tables.h @@ -43,7 +43,7 @@ struct compat_ip6t_entry { __u16 next_offset; compat_uint_t comefrom; struct compat_xt_counters counters; - unsigned char elems[0]; + unsigned char elems[]; }; static inline struct xt_entry_target * |