linux/net/l2tp
Gustavo A. R. Silva af71b090c8 l2tp: 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 the following checkpatch warning:
CHECK: Prefer kernel type 'u8' over 'uint8_t'
#50: FILE: net/l2tp/l2tp_core.h:119:
+	uint8_t			priv[];	/* private data */

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 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-28 12:08:37 -08:00
..
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
l2tp_core.c l2tp: Allow duplicate session creation with UDP 2020-02-04 12:35:49 +01:00
l2tp_core.h l2tp: Replace zero-length array with flexible-array member 2020-02-28 12:08:37 -08:00
l2tp_debugfs.c l2tp: no need to check return value of debugfs_create functions 2019-06-14 08:45:05 -07:00
l2tp_eth.c net: core: add generic lockdep keys 2019-10-24 14:53:48 -07:00
l2tp_ip.c netfilter: drop bridge nf reset from nf_reset 2019-10-01 18:42:15 +02:00
l2tp_ip6.c net: ipv6: add net argument to ip6_dst_lookup_flow 2019-12-04 12:27:12 -08:00
l2tp_netlink.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
l2tp_ppp.c compat_ioctl: pppoe: fix PPPOEIOCSFWD handling 2019-07-30 14:42:13 -07:00