diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-28 18:51:41 -0600 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-02-29 21:52:20 -0800 |
| commit | c61a2a76e5da267d8f5070a34c074d104155c0f6 (patch) | |
| tree | 3526ddf242c26e04084721c0c68a193a57f0b3fc /include/net/mld.h | |
| parent | e8316026d538873f60f41dab4caaa493a21684b0 (diff) | |
net: ipv6: mld: 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/net/mld.h')
| -rw-r--r-- | include/net/mld.h | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/include/net/mld.h b/include/net/mld.h index b0f5b3105ef0..496bddb59942 100644 --- a/include/net/mld.h +++ b/include/net/mld.h @@ -24,12 +24,12 @@ struct mld2_grec { __u8 grec_auxwords; __be16 grec_nsrcs; struct in6_addr grec_mca; - struct in6_addr grec_src[0]; + struct in6_addr grec_src[]; }; struct mld2_report { struct icmp6hdr mld2r_hdr; - struct mld2_grec mld2r_grec[0]; + struct mld2_grec mld2r_grec[]; }; #define mld2r_type mld2r_hdr.icmp6_type @@ -55,7 +55,7 @@ struct mld2_query { #endif __u8 mld2q_qqic; __be16 mld2q_nsrcs; - struct in6_addr mld2q_srcs[0]; + struct in6_addr mld2q_srcs[]; }; #define mld2q_type mld2q_hdr.icmp6_type |