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: Gustavo A. R. Silva <[email protected]> --- Changes in v2: - Use the DEFINE_RAW_FLEX() helper. - Update subject and changelog text. include/net/inet_sock.h | 9 ++-- net/ipv4/icmp.c | 108 +++++++++++++++++++++------------------- net/ipv4/ip_output.c | 13 ++--- net/ipv4/ping.c | 7 +-- net/ipv4/raw.c | 7 +-- net/ipv4/udp.c | 7 +-- 6 files changed, 81 insertions(+), 70 deletions(-) diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h index ac1c75975908..3370159556b8 100644 --- a/include/net/inet_sock.h +++ b/include/net/inet_sock.h @@ -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 { diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index 4abbec2f47ef..19c9c838967f 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -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: diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index ff11d3a85a36..75fcb58795bb 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -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; diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c index ad56588107cc..7e2812668350 100644 --- a/net/ipv4/ping.c +++ b/net/ipv4/ping.c @@ -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(); } diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c index 5998c4cc6f47..e20c41206e29 100644 --- a/net/ipv4/raw.c +++ b/net/ipv4/raw.c @@ -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(); } diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index ffe074cb5865..591527ae811c 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1269,6 +1269,8 @@ EXPORT_IPV6_MOD_GPL(udp_cmsg_send); int udp_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 udp_sock *up = udp_sk(sk); DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name); @@ -1286,7 +1288,6 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) int corkreq = udp_test_bit(CORK, sk) || msg->msg_flags & MSG_MORE; int (*getfrag)(void *, char *, int, int, int, struct sk_buff *); struct sk_buff *skb; - struct ip_options_data opt_copy; int uc_index; if (len > 0xFFFF) @@ -1368,9 +1369,9 @@ int udp_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(); } -- 2.43.0
