diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-28 07:36:41 -0600 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-02-28 12:08:37 -0800 |
| commit | b0c9a2d9a8ee13ec68ff5f80fdd74bd83272f967 (patch) | |
| tree | 7bc76b8ee6001bd441ba1e9b4fbc2d32bf0660c4 /net/ipv6 | |
| parent | 8402a31dd803e091fd2ec9cd22040b34a0b07085 (diff) | |
ipv6: 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 'net/ipv6')
| -rw-r--r-- | net/ipv6/ah6.c | 2 | ||||
| -rw-r--r-- | net/ipv6/seg6_iptunnel.c | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/net/ipv6/ah6.c b/net/ipv6/ah6.c index 95835e8d99aa..871d6e52ec67 100644 --- a/net/ipv6/ah6.c +++ b/net/ipv6/ah6.c @@ -36,7 +36,7 @@ struct tmp_ext { struct in6_addr saddr; #endif struct in6_addr daddr; - char hdrs[0]; + char hdrs[]; }; struct ah_skb_cb { diff --git a/net/ipv6/seg6_iptunnel.c b/net/ipv6/seg6_iptunnel.c index ab7f124ff5d7..d8afe7290de8 100644 --- a/net/ipv6/seg6_iptunnel.c +++ b/net/ipv6/seg6_iptunnel.c @@ -29,7 +29,7 @@ struct seg6_lwt { struct dst_cache cache; - struct seg6_iptunnel_encap tuninfo[0]; + struct seg6_iptunnel_encap tuninfo[]; }; static inline struct seg6_lwt *seg6_lwt_lwtunnel(struct lwtunnel_state *lwt) |