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db243b7964
linux/net/ipv6
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Gustavo A. R. Silva db243b7964 net/ipv4/ipv6: Replace one-element arraya with flexible-array members 
There is a regular need in the kernel to provide a way to declare having
a dynamically sized set of trailing elements in a structure. Kernel code
should always use “flexible array members”[1] for these cases. The older
style of one-element or zero-length arrays should no longer be used[2].

Use an anonymous union with a couple of anonymous structs in order to
keep userspace unchanged and refactor the related code accordingly:

$ pahole -C group_filter net/ipv4/ip_sockglue.o
struct group_filter {
	union {
		struct {
			__u32      gf_interface_aux;     /*     0     4 */

			/* XXX 4 bytes hole, try to pack */

			struct __kernel_sockaddr_storage gf_group_aux; /*     8   128 */
			/* --- cacheline 2 boundary (128 bytes) was 8 bytes ago --- */
			__u32      gf_fmode_aux;         /*   136     4 */
			__u32      gf_numsrc_aux;        /*   140     4 */
			struct __kernel_sockaddr_storage gf_slist[1]; /*   144   128 */
		};                                       /*     0   272 */
		struct {
			__u32      gf_interface;         /*     0     4 */

			/* XXX 4 bytes hole, try to pack */

			struct __kernel_sockaddr_storage gf_group; /*     8   128 */
			/* --- cacheline 2 boundary (128 bytes) was 8 bytes ago --- */
			__u32      gf_fmode;             /*   136     4 */
			__u32      gf_numsrc;            /*   140     4 */
			struct __kernel_sockaddr_storage gf_slist_flex[0]; /*   144     0 */
		};                                       /*     0   144 */
	};                                               /*     0   272 */

	/* size: 272, cachelines: 5, members: 1 */
	/* last cacheline: 16 bytes */
};

$ pahole -C compat_group_filter net/ipv4/ip_sockglue.o
struct compat_group_filter {
	union {
		struct {
			__u32      gf_interface_aux;     /*     0     4 */
			struct __kernel_sockaddr_storage gf_group_aux __attribute__((__aligned__(4))); /*     4   128 */
			/* --- cacheline 2 boundary (128 bytes) was 4 bytes ago --- */
			__u32      gf_fmode_aux;         /*   132     4 */
			__u32      gf_numsrc_aux;        /*   136     4 */
			struct __kernel_sockaddr_storage gf_slist[1] __attribute__((__aligned__(4))); /*   140   128 */
		} __attribute__((__packed__)) __attribute__((__aligned__(4)));                     /*     0   268 */
		struct {
			__u32      gf_interface;         /*     0     4 */
			struct __kernel_sockaddr_storage gf_group __attribute__((__aligned__(4))); /*     4   128 */
			/* --- cacheline 2 boundary (128 bytes) was 4 bytes ago --- */
			__u32      gf_fmode;             /*   132     4 */
			__u32      gf_numsrc;            /*   136     4 */
			struct __kernel_sockaddr_storage gf_slist_flex[0] __attribute__((__aligned__(4))); /*   140     0 */
		} __attribute__((__packed__)) __attribute__((__aligned__(4)));                     /*     0   140 */
	} __attribute__((__aligned__(1)));               /*     0   268 */

	/* size: 268, cachelines: 5, members: 1 */
	/* forced alignments: 1 */
	/* last cacheline: 12 bytes */
} __attribute__((__packed__));

This helps with the ongoing efforts to globally enable -Warray-bounds
and get us closer to being able to tighten the FORTIFY_SOURCE routines
on memcpy().

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.10/process/deprecated.html#zero-length-and-one-element-arrays

Link: https://github.com/KSPP/linux/issues/79
Link: https://github.com/KSPP/linux/issues/109
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-08-05 11:46:42 +01:00
..
ila
netfilter Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-06-18 19:47:02 -07:00
addrconf_core.c ipv6: add ipv6_dev_find to stubs 2021-03-30 13:29:39 -07:00
addrconf.c net: add extack arg for link ops 2021-08-04 10:01:26 +01:00
addrlabel.c ipv6: addrlabel: fix possible memory leak in ip6addrlbl_net_init 2020-11-25 11:20:16 -08:00
af_inet6.c ipv6: ioam: Data plane support for Pre-allocated Trace 2021-07-21 08:14:33 -07:00
ah6.c xfrm: remove hdr_offset indirection 2021-06-11 14:48:50 +02:00
anycast.c ipv6: fix memory leaks on IPV6_ADDRFORM path 2020-07-30 16:30:55 -07:00
calipso.c cipso,calipso: resolve a number of problems with the DOI refcounts 2021-03-04 15:26:57 -08:00
datagram.c lsm,selinux: pass flowi_common instead of flowi to the LSM hooks 2020-11-23 18:36:21 -05:00
esp6_offload.c xfrm: remove description from xfrm_type struct 2021-06-09 09:38:52 +02:00
esp6.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-06-29 15:45:27 -07:00
exthdrs_core.c
exthdrs_offload.c
exthdrs.c ipv6: exthdrs: get rid of indirect calls in ip6_parse_tlv() 2021-08-04 10:34:40 +01:00
fib6_notifier.c
fib6_rules.c ipv6: fib6: remove redundant initialization of variable err 2021-06-14 12:42:26 -07:00
fou6.c
icmp.c ipv6: ICMPV6: add response to ICMPV6 RFC 8335 PROBE messages 2021-06-28 14:29:45 -07:00
inet6_connection_sock.c lsm,selinux: pass flowi_common instead of flowi to the LSM hooks 2020-11-23 18:36:21 -05:00
inet6_hashtables.c net: ipv6: remove unused arg exact_dif in compute_score 2020-08-31 13:08:10 -07:00
ioam6_iptunnel.c ipv6: ioam: Support for IOAM injection with lwtunnels 2021-07-21 08:14:33 -07:00
ioam6.c ipv6: ioam: Support for IOAM injection with lwtunnels 2021-07-21 08:14:33 -07:00
ip6_checksum.c
ip6_fib.c memcg: enable accounting for IP address and routing-related objects 2021-07-20 06:00:38 -07:00
ip6_flowlabel.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-08-05 20:13:21 -07:00
ip6_gre.c ip_tunnel: use ndo_siocdevprivate 2021-07-27 20:11:44 +01:00
ip6_icmp.c net: icmp: pass zeroed opts from icmp{,v6}_ndo_send before sending 2021-02-23 11:29:52 -08:00
ip6_input.c ipv6: weaken the v4mapped source check 2021-03-18 11:19:23 -07:00
ip6_offload.c net/core: move gro function declarations to separate header 2021-02-04 18:37:57 -08:00
ip6_offload.h
ip6_output.c ipv6: use skb_expand_head in ip6_xmit 2021-08-03 11:21:39 +01:00
ip6_tunnel.c ip_tunnel: use ndo_siocdevprivate 2021-07-27 20:11:44 +01:00
ip6_udp_tunnel.c
ip6_vti.c ip_tunnel: use ndo_siocdevprivate 2021-07-27 20:11:44 +01:00
ip6mr.c
ipcomp6.c xfrm: remove hdr_offset indirection 2021-06-11 14:48:50 +02:00
ipv6_sockglue.c net/ipv4/ipv6: Replace one-element arraya with flexible-array members 2021-08-05 11:46:42 +01:00
Kconfig ipv6: ioam: Support for IOAM injection with lwtunnels 2021-07-21 08:14:33 -07:00
Makefile ipv6: ioam: Support for IOAM injection with lwtunnels 2021-07-21 08:14:33 -07:00
mcast_snoop.c net: bridge: mcast: fix broken length + header check for MRDv6 Adv. 2021-04-27 14:02:06 -07:00
mcast.c mld: avoid unnecessary high order page allocation in mld_newpack() 2021-06-14 12:46:00 -07:00
mip6.c xfrm: ipv6: move mip6_rthdr_offset into xfrm core 2021-06-11 14:48:50 +02:00
ndisc.c net: allow user to set metric on default route learned via Router Advertisement 2021-01-26 18:39:45 -08:00
netfilter.c netfilter: Dissect flow after packet mangling 2021-04-18 22:04:16 +02:00
output_core.c ipv6: use prandom_u32() for ID generation 2021-05-31 22:12:08 -07:00
ping.c lsm,selinux: pass flowi_common instead of flowi to the LSM hooks 2020-11-23 18:36:21 -05:00
proc.c net: udp: introduce UDP_MIB_MEMERRORS for udp_mem 2020-11-09 15:34:44 -08:00
protocol.c
raw.c net: sock: introduce sk_error_report 2021-06-29 11:28:21 -07:00
reassembly.c ipv6: record frag_max_size in atomic fragments in input path 2021-05-21 15:02:25 -07:00
route.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-07-23 16:13:06 +01:00
rpl_iptunnel.c net: ipv6: rpl_iptunnel: simplify the return expression of rpl_do_srh() 2020-12-08 16:22:54 -08:00
rpl.c net: ipv6: rpl*: Fix strange kerneldoc warnings due to bad header 2020-10-30 12:12:52 -07:00
seg6_hmac.c crypto: sha - split sha.h into sha1.h and sha2.h 2020-11-20 14:45:33 +11:00
seg6_iptunnel.c seg6_iptunnel: Refactor seg6_lwt_headroom out of uapi header 2020-08-03 17:57:40 -07:00
seg6_local.c seg6: add support for SRv6 End.DT46 Behavior 2021-06-18 11:35:47 -07:00
seg6.c net: Remove redundant assignment to err 2021-04-29 15:34:15 -07:00
sit.c ip_tunnel: use ndo_siocdevprivate 2021-07-27 20:11:44 +01:00
syncookies.c selinux/stable-5.11 PR 20201214 2020-12-16 11:01:04 -08:00
sysctl_net_ipv6.c ipv6: ioam: Data plane support for Pre-allocated Trace 2021-07-21 08:14:33 -07:00
tcp_ipv6.c net: send SYNACK packet with accepted fwmark 2021-07-09 11:24:02 -07:00
tcpv6_offload.c
tunnel6.c
udp_impl.h
udp_offload.c udp: properly complete L4 GRO over UDP tunnel packet 2021-03-30 17:06:49 -07:00
udp.c udp: check encap socket in __udp_lib_err 2021-07-21 08:49:31 -07:00
udplite.c
xfrm6_input.c
xfrm6_output.c net: ipv6: fix return value of ip6_skb_dst_mtu 2021-07-02 11:57:01 -07:00
xfrm6_policy.c
xfrm6_protocol.c
xfrm6_state.c
xfrm6_tunnel.c xfrm: remove description from xfrm_type struct 2021-06-09 09:38:52 +02:00