--- zzzz-none-000/linux-3.10.107/net/ipv6/syncookies.c 2017-06-27 09:49:32.000000000 +0000 +++ scorpion-7490-727/linux-3.10.107/net/ipv6/syncookies.c 2021-02-04 17:41:59.000000000 +0000 @@ -24,56 +24,41 @@ #define COOKIEBITS 24 /* Upper bits store count */ #define COOKIEMASK (((__u32)1 << COOKIEBITS) - 1) -/* Table must be sorted. */ +static u32 syncookie6_secret[2][16-4+SHA_DIGEST_WORDS] __read_mostly; + +/* RFC 2460, Section 8.3: + * [ipv6 tcp] MSS must be computed as the maximum packet size minus 60 [..] + * + * Due to IPV6_MIN_MTU=1280 the lowest possible MSS is 1220, which allows + * using higher values than ipv4 tcp syncookies. + * The other values are chosen based on ethernet (1500 and 9k MTU), plus + * one that accounts for common encap (PPPoe) overhead. Table must be sorted. + */ static __u16 const msstab[] = { - 64, - 512, - 536, - 1280 - 60, + 1280 - 60, /* IPV6_MIN_MTU - 60 */ 1480 - 60, 1500 - 60, - 4460 - 60, 9000 - 60, }; -/* - * This (misnamed) value is the age of syncookie which is permitted. - * Its ideal value should be dependent on TCP_TIMEOUT_INIT and - * sysctl_tcp_retries1. It's a rather complicated formula (exponential - * backoff) to compute at runtime so it's currently hardcoded here. - */ -#define COUNTER_TRIES 4 - -static inline struct sock *get_cookie_sock(struct sock *sk, struct sk_buff *skb, - struct request_sock *req, - struct dst_entry *dst) -{ - struct inet_connection_sock *icsk = inet_csk(sk); - struct sock *child; - - child = icsk->icsk_af_ops->syn_recv_sock(sk, skb, req, dst); - if (child) - inet_csk_reqsk_queue_add(sk, req, child); - else - reqsk_free(req); - - return child; -} - static DEFINE_PER_CPU(__u32 [16 + 5 + SHA_WORKSPACE_WORDS], ipv6_cookie_scratch); static u32 cookie_hash(const struct in6_addr *saddr, const struct in6_addr *daddr, __be16 sport, __be16 dport, u32 count, int c) { - __u32 *tmp = __get_cpu_var(ipv6_cookie_scratch); + __u32 *tmp; + + net_get_random_once(syncookie6_secret, sizeof(syncookie6_secret)); + + tmp = this_cpu_ptr(ipv6_cookie_scratch); /* * we have 320 bits of information to hash, copy in the remaining - * 192 bits required for sha_transform, from the syncookie_secret + * 192 bits required for sha_transform, from the syncookie6_secret * and overwrite the digest with the secret */ - memcpy(tmp + 10, syncookie_secret[c], 44); + memcpy(tmp + 10, syncookie6_secret[c], 44); memcpy(tmp, saddr, 16); memcpy(tmp + 4, daddr, 16); tmp[8] = ((__force u32)sport << 16) + (__force u32)dport; @@ -86,8 +71,9 @@ static __u32 secure_tcp_syn_cookie(const struct in6_addr *saddr, const struct in6_addr *daddr, __be16 sport, __be16 dport, __u32 sseq, - __u32 count, __u32 data) + __u32 data) { + u32 count = tcp_cookie_time(); return (cookie_hash(saddr, daddr, sport, dport, 0, 0) + sseq + (count << COOKIEBITS) + ((cookie_hash(saddr, daddr, sport, dport, count, 1) + data) @@ -96,15 +82,14 @@ static __u32 check_tcp_syn_cookie(__u32 cookie, const struct in6_addr *saddr, const struct in6_addr *daddr, __be16 sport, - __be16 dport, __u32 sseq, __u32 count, - __u32 maxdiff) + __be16 dport, __u32 sseq) { - __u32 diff; + __u32 diff, count = tcp_cookie_time(); cookie -= cookie_hash(saddr, daddr, sport, dport, 0, 0) + sseq; diff = (count - (cookie >> COOKIEBITS)) & ((__u32) -1 >> COOKIEBITS); - if (diff >= maxdiff) + if (diff >= MAX_SYNCOOKIE_AGE) return (__u32)-1; return (cookie - @@ -112,45 +97,46 @@ & COOKIEMASK; } -__u32 cookie_v6_init_sequence(struct sock *sk, const struct sk_buff *skb, __u16 *mssp) +u32 __cookie_v6_init_sequence(const struct ipv6hdr *iph, + const struct tcphdr *th, __u16 *mssp) { - const struct ipv6hdr *iph = ipv6_hdr(skb); - const struct tcphdr *th = tcp_hdr(skb); int mssind; const __u16 mss = *mssp; - tcp_synq_overflow(sk); - for (mssind = ARRAY_SIZE(msstab) - 1; mssind ; mssind--) if (mss >= msstab[mssind]) break; *mssp = msstab[mssind]; - NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_SYNCOOKIESSENT); - return secure_tcp_syn_cookie(&iph->saddr, &iph->daddr, th->source, - th->dest, ntohl(th->seq), - jiffies / (HZ * 60), mssind); + th->dest, ntohl(th->seq), mssind); } +EXPORT_SYMBOL_GPL(__cookie_v6_init_sequence); -static inline int cookie_check(const struct sk_buff *skb, __u32 cookie) +__u32 cookie_v6_init_sequence(const struct sk_buff *skb, __u16 *mssp) { const struct ipv6hdr *iph = ipv6_hdr(skb); const struct tcphdr *th = tcp_hdr(skb); + + return __cookie_v6_init_sequence(iph, th, mssp); +} + +int __cookie_v6_check(const struct ipv6hdr *iph, const struct tcphdr *th, + __u32 cookie) +{ __u32 seq = ntohl(th->seq) - 1; __u32 mssind = check_tcp_syn_cookie(cookie, &iph->saddr, &iph->daddr, - th->source, th->dest, seq, - jiffies / (HZ * 60), COUNTER_TRIES); + th->source, th->dest, seq); return mssind < ARRAY_SIZE(msstab) ? msstab[mssind] : 0; } +EXPORT_SYMBOL_GPL(__cookie_v6_check); struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb) { struct tcp_options_received tcp_opt; struct inet_request_sock *ireq; - struct inet6_request_sock *ireq6; struct tcp_request_sock *treq; struct ipv6_pinfo *np = inet6_sk(sk); struct tcp_sock *tp = tcp_sk(sk); @@ -161,13 +147,15 @@ int mss; struct dst_entry *dst; __u8 rcv_wscale; - bool ecn_ok = false; if (!sysctl_tcp_syncookies || !th->ack || th->rst) goto out; - if (tcp_synq_no_recent_overflow(sk) || - (mss = cookie_check(skb, cookie)) == 0) { + if (tcp_synq_no_recent_overflow(sk)) + goto out; + + mss = __cookie_v6_check(ipv6_hdr(skb), th, cookie); + if (mss == 0) { NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_SYNCOOKIESFAILED); goto out; } @@ -178,49 +166,48 @@ memset(&tcp_opt, 0, sizeof(tcp_opt)); tcp_parse_options(skb, &tcp_opt, 0, NULL); - if (!cookie_check_timestamp(&tcp_opt, sock_net(sk), &ecn_ok)) + if (!cookie_timestamp_decode(&tcp_opt)) goto out; ret = NULL; - req = inet6_reqsk_alloc(&tcp6_request_sock_ops); + req = inet_reqsk_alloc(&tcp6_request_sock_ops, sk, false); if (!req) goto out; ireq = inet_rsk(req); - ireq6 = inet6_rsk(req); treq = tcp_rsk(req); - treq->listener = NULL; + treq->tfo_listener = false; if (security_inet_conn_request(sk, skb, req)) goto out_free; req->mss = mss; - ireq->rmt_port = th->source; - ireq->loc_port = th->dest; - ireq6->rmt_addr = ipv6_hdr(skb)->saddr; - ireq6->loc_addr = ipv6_hdr(skb)->daddr; - if (ipv6_opt_accepted(sk, skb) || + ireq->ir_rmt_port = th->source; + ireq->ir_num = ntohs(th->dest); + ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr; + ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr; + if (ipv6_opt_accepted(sk, skb, &TCP_SKB_CB(skb)->header.h6) || np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) { atomic_inc(&skb->users); - ireq6->pktopts = skb; + ireq->pktopts = skb; } - ireq6->iif = sk->sk_bound_dev_if; + ireq->ir_iif = sk->sk_bound_dev_if; /* So that link locals have meaning */ if (!sk->sk_bound_dev_if && - ipv6_addr_type(&ireq6->rmt_addr) & IPV6_ADDR_LINKLOCAL) - ireq6->iif = inet6_iif(skb); + ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL) + ireq->ir_iif = tcp_v6_iif(skb); + + ireq->ir_mark = inet_request_mark(sk, skb); - req->expires = 0UL; req->num_retrans = 0; - ireq->ecn_ok = ecn_ok; ireq->snd_wscale = tcp_opt.snd_wscale; ireq->sack_ok = tcp_opt.sack_ok; ireq->wscale_ok = tcp_opt.wscale_ok; ireq->tstamp_ok = tcp_opt.saw_tstamp; req->ts_recent = tcp_opt.saw_tstamp ? tcp_opt.rcv_tsval : 0; - treq->snt_synack = tcp_opt.saw_tstamp ? tcp_opt.rcv_tsecr : 0; + treq->snt_synack.v64 = 0; treq->rcv_isn = ntohl(th->seq) - 1; treq->snt_isn = cookie; @@ -234,33 +221,33 @@ struct flowi6 fl6; memset(&fl6, 0, sizeof(fl6)); fl6.flowi6_proto = IPPROTO_TCP; - fl6.daddr = ireq6->rmt_addr; - final_p = fl6_update_dst(&fl6, np->opt, &final); - fl6.saddr = ireq6->loc_addr; + fl6.daddr = ireq->ir_v6_rmt_addr; + final_p = fl6_update_dst(&fl6, rcu_dereference(np->opt), &final); + fl6.saddr = ireq->ir_v6_loc_addr; fl6.flowi6_oif = sk->sk_bound_dev_if; - fl6.flowi6_mark = sk->sk_mark; - fl6.fl6_dport = inet_rsk(req)->rmt_port; + fl6.flowi6_mark = ireq->ir_mark; + fl6.fl6_dport = ireq->ir_rmt_port; fl6.fl6_sport = inet_sk(sk)->inet_sport; security_req_classify_flow(req, flowi6_to_flowi(&fl6)); - dst = ip6_dst_lookup_flow(sk, &fl6, final_p, false); + dst = ip6_dst_lookup_flow(sk, &fl6, final_p); if (IS_ERR(dst)) goto out_free; } - req->window_clamp = tp->window_clamp ? :dst_metric(dst, RTAX_WINDOW); + req->rsk_window_clamp = tp->window_clamp ? :dst_metric(dst, RTAX_WINDOW); tcp_select_initial_window(tcp_full_space(sk), req->mss, - &req->rcv_wnd, &req->window_clamp, + &req->rsk_rcv_wnd, &req->rsk_window_clamp, ireq->wscale_ok, &rcv_wscale, dst_metric(dst, RTAX_INITRWND)); ireq->rcv_wscale = rcv_wscale; + ireq->ecn_ok = cookie_ecn_ok(&tcp_opt, sock_net(sk), dst); - ret = get_cookie_sock(sk, skb, req, dst); + ret = tcp_get_cookie_sock(sk, skb, req, dst); out: return ret; out_free: reqsk_free(req); return NULL; } -