Contributors: 33
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Glenn Griffin |
412 |
27.91% |
1 |
0.95% |
| Linus Torvalds (pre-git) |
263 |
17.82% |
16 |
15.24% |
| Kuniyuki Iwashima |
139 |
9.42% |
10 |
9.52% |
| Florian Westphal |
99 |
6.71% |
12 |
11.43% |
| Eric Dumazet |
90 |
6.10% |
19 |
18.10% |
| Jason A. Donenfeld |
69 |
4.67% |
1 |
0.95% |
| Matt Mackall |
69 |
4.67% |
3 |
2.86% |
| Jason Xing |
55 |
3.73% |
2 |
1.90% |
| David S. Miller |
51 |
3.46% |
6 |
5.71% |
| Patrick McHardy |
48 |
3.25% |
1 |
0.95% |
| Arnaldo Carvalho de Melo |
36 |
2.44% |
7 |
6.67% |
| Mao Wenan |
32 |
2.17% |
1 |
0.95% |
| Hannes Frederic Sowa |
17 |
1.15% |
1 |
0.95% |
| Venkat Yekkirala |
13 |
0.88% |
2 |
1.90% |
| Linus Torvalds |
11 |
0.75% |
2 |
1.90% |
| Dmitry Safonov |
10 |
0.68% |
1 |
0.95% |
| Lorenzo Colitti |
10 |
0.68% |
2 |
1.90% |
| Al Viro |
9 |
0.61% |
2 |
1.90% |
| Arnaud Ebalard |
7 |
0.47% |
1 |
0.95% |
| Laurent Chavey |
7 |
0.47% |
1 |
0.95% |
| Alexey Dobriyan |
5 |
0.34% |
2 |
1.90% |
| Brian Haley |
3 |
0.20% |
1 |
0.95% |
| Alexey Kuznetsov |
3 |
0.20% |
1 |
0.95% |
| Yan Zhai |
3 |
0.20% |
1 |
0.95% |
| Nikolay Borisov |
3 |
0.20% |
1 |
0.95% |
| Yuchung Cheng |
2 |
0.14% |
1 |
0.95% |
| Pavel Emelyanov |
2 |
0.14% |
1 |
0.95% |
| David Ahern |
2 |
0.14% |
1 |
0.95% |
| Thomas Gleixner |
2 |
0.14% |
1 |
0.95% |
| Sabrina Dubroca |
1 |
0.07% |
1 |
0.95% |
| Paul Moore |
1 |
0.07% |
1 |
0.95% |
| Hideaki Yoshifuji / 吉藤英明 |
1 |
0.07% |
1 |
0.95% |
| Elena Reshetova |
1 |
0.07% |
1 |
0.95% |
| Total |
1476 |
|
105 |
|
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* IPv6 Syncookies implementation for the Linux kernel
*
* Authors:
* Glenn Griffin <ggriffin.kernel@gmail.com>
*
* Based on IPv4 implementation by Andi Kleen
* linux/net/ipv4/syncookies.c
*/
#include <linux/tcp.h>
#include <linux/random.h>
#include <linux/siphash.h>
#include <linux/kernel.h>
#include <net/secure_seq.h>
#include <net/ipv6.h>
#include <net/tcp.h>
#define COOKIEBITS 24 /* Upper bits store count */
#define COOKIEMASK (((__u32)1 << COOKIEBITS) - 1)
static siphash_aligned_key_t syncookie6_secret[2];
/* 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[] = {
1280 - 60, /* IPV6_MIN_MTU - 60 */
1480 - 60,
1500 - 60,
9000 - 60,
};
static u32 cookie_hash(const struct in6_addr *saddr,
const struct in6_addr *daddr,
__be16 sport, __be16 dport, u32 count, int c)
{
const struct {
struct in6_addr saddr;
struct in6_addr daddr;
u32 count;
__be16 sport;
__be16 dport;
} __aligned(SIPHASH_ALIGNMENT) combined = {
.saddr = *saddr,
.daddr = *daddr,
.count = count,
.sport = sport,
.dport = dport
};
net_get_random_once(syncookie6_secret, sizeof(syncookie6_secret));
return siphash(&combined, offsetofend(typeof(combined), dport),
&syncookie6_secret[c]);
}
static __u32 secure_tcp_syn_cookie(const struct in6_addr *saddr,
const struct in6_addr *daddr,
__be16 sport, __be16 dport, __u32 sseq,
__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)
& COOKIEMASK));
}
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 diff, count = tcp_cookie_time();
cookie -= cookie_hash(saddr, daddr, sport, dport, 0, 0) + sseq;
diff = (count - (cookie >> COOKIEBITS)) & ((__u32) -1 >> COOKIEBITS);
if (diff >= MAX_SYNCOOKIE_AGE)
return (__u32)-1;
return (cookie -
cookie_hash(saddr, daddr, sport, dport, count - diff, 1))
& COOKIEMASK;
}
u32 __cookie_v6_init_sequence(const struct ipv6hdr *iph,
const struct tcphdr *th, __u16 *mssp)
{
int mssind;
const __u16 mss = *mssp;
for (mssind = ARRAY_SIZE(msstab) - 1; mssind ; mssind--)
if (mss >= msstab[mssind])
break;
*mssp = msstab[mssind];
return secure_tcp_syn_cookie(&iph->saddr, &iph->daddr, th->source,
th->dest, ntohl(th->seq), mssind);
}
EXPORT_SYMBOL_GPL(__cookie_v6_init_sequence);
__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 = ntohl(th->ack_seq) - 1;
__u32 seq = ntohl(th->seq) - 1;
__u32 mssind;
mssind = check_tcp_syn_cookie(cookie, &iph->saddr, &iph->daddr,
th->source, th->dest, seq);
return mssind < ARRAY_SIZE(msstab) ? msstab[mssind] : 0;
}
EXPORT_SYMBOL_GPL(__cookie_v6_check);
static struct request_sock *cookie_tcp_check(struct net *net, struct sock *sk,
struct sk_buff *skb)
{
struct tcp_options_received tcp_opt;
u32 tsoff = 0;
int mss;
if (tcp_synq_no_recent_overflow(sk))
goto out;
mss = __cookie_v6_check(ipv6_hdr(skb), tcp_hdr(skb));
if (!mss) {
__NET_INC_STATS(net, LINUX_MIB_SYNCOOKIESFAILED);
goto out;
}
__NET_INC_STATS(net, LINUX_MIB_SYNCOOKIESRECV);
/* check for timestamp cookie support */
memset(&tcp_opt, 0, sizeof(tcp_opt));
tcp_parse_options(net, skb, &tcp_opt, 0, NULL);
if (tcp_opt.saw_tstamp && tcp_opt.rcv_tsecr) {
tsoff = secure_tcpv6_ts_off(net,
ipv6_hdr(skb)->daddr.s6_addr32,
ipv6_hdr(skb)->saddr.s6_addr32);
tcp_opt.rcv_tsecr -= tsoff;
}
if (!cookie_timestamp_decode(net, &tcp_opt))
goto out;
return cookie_tcp_reqsk_alloc(&tcp6_request_sock_ops, sk, skb,
&tcp_opt, mss, tsoff);
out:
return ERR_PTR(-EINVAL);
}
struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
{
const struct tcphdr *th = tcp_hdr(skb);
struct ipv6_pinfo *np = inet6_sk(sk);
struct tcp_sock *tp = tcp_sk(sk);
struct inet_request_sock *ireq;
struct net *net = sock_net(sk);
struct request_sock *req;
struct dst_entry *dst;
struct sock *ret = sk;
__u8 rcv_wscale;
int full_space;
SKB_DR(reason);
if (!READ_ONCE(net->ipv4.sysctl_tcp_syncookies) ||
!th->ack || th->rst)
goto out;
if (cookie_bpf_ok(skb)) {
req = cookie_bpf_check(sk, skb);
} else {
req = cookie_tcp_check(net, sk, skb);
if (IS_ERR(req))
goto out;
}
if (!req) {
SKB_DR_SET(reason, NO_SOCKET);
goto out_drop;
}
ireq = inet_rsk(req);
ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
if (security_inet_conn_request(sk, skb, req)) {
SKB_DR_SET(reason, SECURITY_HOOK);
goto out_free;
}
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) {
refcount_inc(&skb->users);
ireq->pktopts = skb;
}
/* So that link locals have meaning */
if (!sk->sk_bound_dev_if &&
ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
ireq->ir_iif = tcp_v6_iif(skb);
tcp_ao_syncookie(sk, skb, req, AF_INET6);
/*
* We need to lookup the dst_entry to get the correct window size.
* This is taken from tcp_v6_syn_recv_sock. Somebody please enlighten
* me if there is a preferred way.
*/
{
struct in6_addr *final_p, final;
struct flowi6 fl6;
memset(&fl6, 0, sizeof(fl6));
fl6.flowi6_proto = IPPROTO_TCP;
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 = ireq->ir_iif;
fl6.flowi6_mark = ireq->ir_mark;
fl6.fl6_dport = ireq->ir_rmt_port;
fl6.fl6_sport = inet_sk(sk)->inet_sport;
fl6.flowi6_uid = sk->sk_uid;
security_req_classify_flow(req, flowi6_to_flowi_common(&fl6));
dst = ip6_dst_lookup_flow(net, sk, &fl6, final_p);
if (IS_ERR(dst)) {
SKB_DR_SET(reason, IP_OUTNOROUTES);
goto out_free;
}
}
req->rsk_window_clamp = READ_ONCE(tp->window_clamp) ? :dst_metric(dst, RTAX_WINDOW);
/* limit the window selection if the user enforce a smaller rx buffer */
full_space = tcp_full_space(sk);
if (sk->sk_userlocks & SOCK_RCVBUF_LOCK &&
(req->rsk_window_clamp > full_space || req->rsk_window_clamp == 0))
req->rsk_window_clamp = full_space;
tcp_select_initial_window(sk, full_space, req->mss,
&req->rsk_rcv_wnd, &req->rsk_window_clamp,
ireq->wscale_ok, &rcv_wscale,
dst_metric(dst, RTAX_INITRWND));
/* req->syncookie is set true only if ACK is validated
* by BPF kfunc, then, rcv_wscale is already configured.
*/
if (!req->syncookie)
ireq->rcv_wscale = rcv_wscale;
ireq->ecn_ok &= cookie_ecn_ok(net, dst);
ret = tcp_get_cookie_sock(sk, skb, req, dst);
if (!ret) {
SKB_DR_SET(reason, NO_SOCKET);
goto out_drop;
}
out:
return ret;
out_free:
reqsk_free(req);
out_drop:
sk_skb_reason_drop(sk, skb, reason);
return NULL;
}