diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-20 07:59:14 -0600 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2020-03-15 15:20:16 +0100 |
| commit | 6daf14140129d30207ed6a0a69851fa6a3636bda (patch) | |
| tree | 43f5f5d662db9cfc241ba1c848f17694b95a16ff /include/net | |
| parent | eb9d7af3b7bd6d1b51c6522de53a5bf9c57e81db (diff) | |
| download | linux-6daf14140129d30207ed6a0a69851fa6a3636bda.tar.bz2 | |
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/net')
| -rw-r--r-- | include/net/netfilter/nf_conntrack_extend.h | 2 | ||||
| -rw-r--r-- | include/net/netfilter/nf_conntrack_timeout.h | 2 | ||||
| -rw-r--r-- | include/net/netfilter/nf_tables.h | 6 |
3 files changed, 5 insertions, 5 deletions
diff --git a/include/net/netfilter/nf_conntrack_extend.h b/include/net/netfilter/nf_conntrack_extend.h index 5ae5295aa46d..e1e588387103 100644 --- a/include/net/netfilter/nf_conntrack_extend.h +++ b/include/net/netfilter/nf_conntrack_extend.h @@ -45,7 +45,7 @@ enum nf_ct_ext_id { struct nf_ct_ext { u8 offset[NF_CT_EXT_NUM]; u8 len; - char data[0]; + char data[]; }; static inline bool __nf_ct_ext_exist(const struct nf_ct_ext *ext, u8 id) diff --git a/include/net/netfilter/nf_conntrack_timeout.h b/include/net/netfilter/nf_conntrack_timeout.h index 6dd72396f534..659b0ea25b4d 100644 --- a/include/net/netfilter/nf_conntrack_timeout.h +++ b/include/net/netfilter/nf_conntrack_timeout.h @@ -14,7 +14,7 @@ struct nf_ct_timeout { __u16 l3num; const struct nf_conntrack_l4proto *l4proto; - char data[0]; + char data[]; }; struct ctnl_timeout { diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h index d913cdb6a27b..01f48b5e6bf2 100644 --- a/include/net/netfilter/nf_tables.h +++ b/include/net/netfilter/nf_tables.h @@ -224,7 +224,7 @@ int nft_validate_register_store(const struct nft_ctx *ctx, */ struct nft_userdata { u8 len; - unsigned char data[0]; + unsigned char data[]; }; /** @@ -565,7 +565,7 @@ struct nft_set_ext_tmpl { struct nft_set_ext { u8 genmask; u8 offset[NFT_SET_EXT_NUM]; - char data[0]; + char data[]; }; static inline void nft_set_ext_prepare(struct nft_set_ext_tmpl *tmpl) @@ -1375,7 +1375,7 @@ struct nft_trans { int msg_type; bool put_net; struct nft_ctx ctx; - char data[0]; + char data[]; }; struct nft_trans_rule { |