Commit c86af46b authored by Gustavo A. R. Silva's avatar Gustavo A. R. Silva Committed by Jakub Kicinski
Browse files

ipv4/inet_sock.h: Avoid thousands of -Wflex-array-member-not-at-end warnings 



Use DEFINE_RAW_FLEX() to avoid thousands of -Wflex-array-member-not-at-end
warnings.

Remove struct ip_options_data, and adjust the rest of the code so that
flexible-array member struct ip_options_rcu::opt.__data[] ends last
in struct icmp_bxm.

Compensate for this by using the DEFINE_RAW_FLEX() helper to define each
on-stack struct instance that contained struct ip_options_data as a member,
and to define struct ip_options_rcu with a fixed on-stack size for its
nested flexible-array member opt.__data[].

Also, add a couple of code comments to prevent people from adding members
to a struct after another member that contains a flexible array.

With these changes, fix 2600 warnings of the following type:

include/net/inet_sock.h:65:33: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]

Signed-off-by: default avatarGustavo A. R. Silva <gustavoars@kernel.org>
Link: https://patch.msgid.link/aVteBadWA6AbTp7X@kspp


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 915a5f60

include/net/inet_sock.h

+4 −5
Original line number Diff line number Diff line
@@ -26,6 +26,8 @@ 
#include <net/tcp_states.h>

#include <net/l3mdev.h>



#define IP_OPTIONS_DATA_FIXED_SIZE 40



/** struct ip_options - IP Options

 *

 * @faddr - Saved first hop address
@@ -58,12 +60,9 @@ struct ip_options { 


struct ip_options_rcu {

	struct rcu_head rcu;

	struct ip_options opt;

};



struct ip_options_data {

	struct ip_options_rcu	opt;

	char			data[40];

	/* Must be last as it ends in a flexible-array member. */

	struct ip_options opt;

};



struct inet_request_sock {

net/ipv4/icmp.c

+58 −50
Original line number Diff line number Diff line
@@ -112,7 +112,9 @@ struct icmp_bxm { 
		__be32	       times[3];

	} data;

	int head_len;

	struct ip_options_data replyopts;



	/* Must be last as it ends in a flexible-array member. */

	struct ip_options_rcu replyopts;

};



/* An array of errno for error messages from dest unreach. */
@@ -353,9 +355,12 @@ void icmp_out_count(struct net *net, unsigned char type) 
static int icmp_glue_bits(void *from, char *to, int offset, int len, int odd,

			  struct sk_buff *skb)

{

	struct icmp_bxm *icmp_param = from;

	DEFINE_RAW_FLEX(struct icmp_bxm, icmp_param, replyopts.opt.__data,

			IP_OPTIONS_DATA_FIXED_SIZE);

	__wsum csum;



	icmp_param = from;



	csum = skb_copy_and_csum_bits(icmp_param->skb,

				      icmp_param->offset + offset,

				      to, len);
@@ -413,7 +418,7 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb) 
	int type = icmp_param->data.icmph.type;

	int code = icmp_param->data.icmph.code;



	if (ip_options_echo(net, &icmp_param->replyopts.opt.opt, skb))

	if (ip_options_echo(net, &icmp_param->replyopts.opt, skb))

		return;



	/* Needed by both icmpv4_global_allow and icmp_xmit_lock */
@@ -435,10 +440,10 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb) 
	daddr = ipc.addr = ip_hdr(skb)->saddr;

	saddr = fib_compute_spec_dst(skb);



	if (icmp_param->replyopts.opt.opt.optlen) {

		ipc.opt = &icmp_param->replyopts.opt;

	if (icmp_param->replyopts.opt.optlen) {

		ipc.opt = &icmp_param->replyopts;

		if (ipc.opt->opt.srr)

			daddr = icmp_param->replyopts.opt.opt.faddr;

			daddr = icmp_param->replyopts.opt.faddr;

	}

	memset(&fl4, 0, sizeof(fl4));

	fl4.daddr = daddr;
@@ -491,8 +496,8 @@ static struct rtable *icmp_route_lookup(struct net *net, struct flowi4 *fl4, 
	int err;



	memset(fl4, 0, sizeof(*fl4));

	fl4->daddr = (param->replyopts.opt.opt.srr ?

		      param->replyopts.opt.opt.faddr : iph->saddr);

	fl4->daddr = (param->replyopts.opt.srr ?

		      param->replyopts.opt.faddr : iph->saddr);

	fl4->saddr = saddr;

	fl4->flowi4_mark = mark;

	fl4->flowi4_uid = sock_net_uid(net, NULL);
@@ -775,9 +780,10 @@ icmp_ext_append(struct net *net, struct sk_buff *skb_in, struct icmphdr *icmph, 
void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info,

		 const struct inet_skb_parm *parm)

{

	DEFINE_RAW_FLEX(struct icmp_bxm, icmp_param, replyopts.opt.__data,

			IP_OPTIONS_DATA_FIXED_SIZE);

	struct iphdr *iph;

	int room;

	struct icmp_bxm icmp_param;

	struct rtable *rt = skb_rtable(skb_in);

	bool apply_ratelimit = false;

	struct sk_buff *ext_skb;
@@ -906,7 +912,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, 
					   iph->tos;

	mark = IP4_REPLY_MARK(net, skb_in->mark);



	if (__ip_options_echo(net, &icmp_param.replyopts.opt.opt, skb_in,

	if (__ip_options_echo(net, &icmp_param->replyopts.opt, skb_in,

			      &parm->opt))

		goto out_unlock;
@@ -915,21 +921,21 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, 
	 *	Prepare data for ICMP header.

	 */



	icmp_param.data.icmph.type	 = type;

	icmp_param.data.icmph.code	 = code;

	icmp_param.data.icmph.un.gateway = info;

	icmp_param.data.icmph.checksum	 = 0;

	icmp_param.skb	  = skb_in;

	icmp_param.offset = skb_network_offset(skb_in);

	icmp_param->data.icmph.type	 = type;

	icmp_param->data.icmph.code	 = code;

	icmp_param->data.icmph.un.gateway = info;

	icmp_param->data.icmph.checksum	 = 0;

	icmp_param->skb	  = skb_in;

	icmp_param->offset = skb_network_offset(skb_in);

	ipcm_init(&ipc);

	ipc.tos = tos;

	ipc.addr = iph->saddr;

	ipc.opt = &icmp_param.replyopts.opt;

	ipc.opt = &icmp_param->replyopts;

	ipc.sockc.mark = mark;



	rt = icmp_route_lookup(net, &fl4, skb_in, iph, saddr,

			       inet_dsfield_to_dscp(tos), mark, type, code,

			       &icmp_param);

			       icmp_param);

	if (IS_ERR(rt))

		goto out_unlock;
@@ -942,7 +948,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, 
	room = dst_mtu(&rt->dst);

	if (room > 576)

		room = 576;

	room -= sizeof(struct iphdr) + icmp_param.replyopts.opt.opt.optlen;

	room -= sizeof(struct iphdr) + icmp_param->replyopts.opt.optlen;

	room -= sizeof(struct icmphdr);

	/* Guard against tiny mtu. We need to include at least one

	 * IP network header for this message to make any sense.
@@ -950,15 +956,15 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, 
	if (room <= (int)sizeof(struct iphdr))

		goto ende;



	ext_skb = icmp_ext_append(net, skb_in, &icmp_param.data.icmph, room,

	ext_skb = icmp_ext_append(net, skb_in, &icmp_param->data.icmph, room,

				  parm->iif);

	if (ext_skb)

		icmp_param.skb = ext_skb;

		icmp_param->skb = ext_skb;



	icmp_param.data_len = icmp_param.skb->len - icmp_param.offset;

	if (icmp_param.data_len > room)

		icmp_param.data_len = room;

	icmp_param.head_len = sizeof(struct icmphdr);

	icmp_param->data_len = icmp_param->skb->len - icmp_param->offset;

	if (icmp_param->data_len > room)

		icmp_param->data_len = room;

	icmp_param->head_len = sizeof(struct icmphdr);



	/* if we don't have a source address at this point, fall back to the

	 * dummy address instead of sending out a packet with a source address
@@ -969,7 +975,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, 


	trace_icmp_send(skb_in, type, code);



	icmp_push_reply(sk, &icmp_param, &fl4, &ipc, &rt);

	icmp_push_reply(sk, icmp_param, &fl4, &ipc, &rt);



	if (ext_skb)

		consume_skb(ext_skb);
@@ -1206,7 +1212,8 @@ static enum skb_drop_reason icmp_redirect(struct sk_buff *skb) 


static enum skb_drop_reason icmp_echo(struct sk_buff *skb)

{

	struct icmp_bxm icmp_param;

	DEFINE_RAW_FLEX(struct icmp_bxm, icmp_param, replyopts.opt.__data,

			IP_OPTIONS_DATA_FIXED_SIZE);

	struct net *net;



	net = skb_dst_dev_net_rcu(skb);
@@ -1214,18 +1221,18 @@ static enum skb_drop_reason icmp_echo(struct sk_buff *skb) 
	if (READ_ONCE(net->ipv4.sysctl_icmp_echo_ignore_all))

		return SKB_NOT_DROPPED_YET;



	icmp_param.data.icmph	   = *icmp_hdr(skb);

	icmp_param.skb		   = skb;

	icmp_param.offset	   = 0;

	icmp_param.data_len	   = skb->len;

	icmp_param.head_len	   = sizeof(struct icmphdr);

	icmp_param->data.icmph	   = *icmp_hdr(skb);

	icmp_param->skb		   = skb;

	icmp_param->offset	   = 0;

	icmp_param->data_len	   = skb->len;

	icmp_param->head_len	   = sizeof(struct icmphdr);



	if (icmp_param.data.icmph.type == ICMP_ECHO)

		icmp_param.data.icmph.type = ICMP_ECHOREPLY;

	else if (!icmp_build_probe(skb, &icmp_param.data.icmph))

	if (icmp_param->data.icmph.type == ICMP_ECHO)

		icmp_param->data.icmph.type = ICMP_ECHOREPLY;

	else if (!icmp_build_probe(skb, &icmp_param->data.icmph))

		return SKB_NOT_DROPPED_YET;



	icmp_reply(&icmp_param, skb);

	icmp_reply(icmp_param, skb);

	return SKB_NOT_DROPPED_YET;

}
@@ -1353,7 +1360,8 @@ EXPORT_SYMBOL_GPL(icmp_build_probe); 
 */

static enum skb_drop_reason icmp_timestamp(struct sk_buff *skb)

{

	struct icmp_bxm icmp_param;

	DEFINE_RAW_FLEX(struct icmp_bxm, icmp_param, replyopts.opt.__data,

			IP_OPTIONS_DATA_FIXED_SIZE);

	/*

	 *	Too short.

	 */
@@ -1363,19 +1371,19 @@ static enum skb_drop_reason icmp_timestamp(struct sk_buff *skb) 
	/*

	 *	Fill in the current time as ms since midnight UT:

	 */

	icmp_param.data.times[1] = inet_current_timestamp();

	icmp_param.data.times[2] = icmp_param.data.times[1];



	BUG_ON(skb_copy_bits(skb, 0, &icmp_param.data.times[0], 4));



	icmp_param.data.icmph	   = *icmp_hdr(skb);

	icmp_param.data.icmph.type = ICMP_TIMESTAMPREPLY;

	icmp_param.data.icmph.code = 0;

	icmp_param.skb		   = skb;

	icmp_param.offset	   = 0;

	icmp_param.data_len	   = 0;

	icmp_param.head_len	   = sizeof(struct icmphdr) + 12;

	icmp_reply(&icmp_param, skb);

	icmp_param->data.times[1] = inet_current_timestamp();

	icmp_param->data.times[2] = icmp_param->data.times[1];



	BUG_ON(skb_copy_bits(skb, 0, &icmp_param->data.times[0], 4));



	icmp_param->data.icmph	   = *icmp_hdr(skb);

	icmp_param->data.icmph.type = ICMP_TIMESTAMPREPLY;

	icmp_param->data.icmph.code = 0;

	icmp_param->skb		   = skb;

	icmp_param->offset	   = 0;

	icmp_param->data_len	   = 0;

	icmp_param->head_len	   = sizeof(struct icmphdr) + 12;

	icmp_reply(icmp_param, skb);

	return SKB_NOT_DROPPED_YET;



out_err:

net/ipv4/ip_output.c

+7 −6
Original line number Diff line number Diff line
@@ -1606,7 +1606,8 @@ void ip_send_unicast_reply(struct sock *sk, const struct sock *orig_sk, 
			   const struct ip_reply_arg *arg,

			   unsigned int len, u64 transmit_time, u32 txhash)

{

	struct ip_options_data replyopts;

	DEFINE_RAW_FLEX(struct ip_options_rcu, replyopts, opt.__data,

			IP_OPTIONS_DATA_FIXED_SIZE);

	struct ipcm_cookie ipc;

	struct flowi4 fl4;

	struct rtable *rt = skb_rtable(skb);
@@ -1615,18 +1616,18 @@ void ip_send_unicast_reply(struct sock *sk, const struct sock *orig_sk, 
	int err;

	int oif;



	if (__ip_options_echo(net, &replyopts.opt.opt, skb, sopt))

	if (__ip_options_echo(net, &replyopts->opt, skb, sopt))

		return;



	ipcm_init(&ipc);

	ipc.addr = daddr;

	ipc.sockc.transmit_time = transmit_time;



	if (replyopts.opt.opt.optlen) {

		ipc.opt = &replyopts.opt;

	if (replyopts->opt.optlen) {

		ipc.opt = replyopts;



		if (replyopts.opt.opt.srr)

			daddr = replyopts.opt.opt.faddr;

		if (replyopts->opt.srr)

			daddr = replyopts->opt.faddr;

	}



	oif = arg->bound_dev_if;

net/ipv4/ping.c

+4 −3
Original line number Diff line number Diff line
@@ -690,6 +690,8 @@ EXPORT_IPV6_MOD_GPL(ping_common_sendmsg); 


static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)

{

	DEFINE_RAW_FLEX(struct ip_options_rcu, opt_copy, opt.__data,

			IP_OPTIONS_DATA_FIXED_SIZE);

	struct net *net = sock_net(sk);

	struct flowi4 fl4;

	struct inet_sock *inet = inet_sk(sk);
@@ -697,7 +699,6 @@ static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 
	struct icmphdr user_icmph;

	struct pingfakehdr pfh;

	struct rtable *rt = NULL;

	struct ip_options_data opt_copy;

	int free = 0;

	__be32 saddr, daddr, faddr;

	u8 scope;
@@ -746,9 +747,9 @@ static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 
		rcu_read_lock();

		inet_opt = rcu_dereference(inet->inet_opt);

		if (inet_opt) {

			memcpy(&opt_copy, inet_opt,

			memcpy(opt_copy, inet_opt,

			       sizeof(*inet_opt) + inet_opt->opt.optlen);

			ipc.opt = &opt_copy.opt;

			ipc.opt = opt_copy;

		}

		rcu_read_unlock();

	}

net/ipv4/raw.c

+4 −3
Original line number Diff line number Diff line
@@ -481,6 +481,8 @@ static int raw_getfrag(void *from, char *to, int offset, int len, int odd, 


static int raw_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)

{

	DEFINE_RAW_FLEX(struct ip_options_rcu, opt_copy, opt.__data,

			IP_OPTIONS_DATA_FIXED_SIZE);

	struct inet_sock *inet = inet_sk(sk);

	struct net *net = sock_net(sk);

	struct ipcm_cookie ipc;
@@ -491,7 +493,6 @@ static int raw_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 
	__be32 daddr;

	__be32 saddr;

	int uc_index, err;

	struct ip_options_data opt_copy;

	struct raw_frag_vec rfv;

	int hdrincl;
@@ -561,9 +562,9 @@ static int raw_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 
		rcu_read_lock();

		inet_opt = rcu_dereference(inet->inet_opt);

		if (inet_opt) {

			memcpy(&opt_copy, inet_opt,

			memcpy(opt_copy, inet_opt,

			       sizeof(*inet_opt) + inet_opt->opt.optlen);

			ipc.opt = &opt_copy.opt;

			ipc.opt = opt_copy;

		}

		rcu_read_unlock();

	}