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tcp: Fix data-races around sysctl knobs related to SYN option.

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While reading these knobs, they can be changed concurrently.
Thus, we need to add READ_ONCE() to their readers.

  - tcp_sack
  - tcp_window_scaling
  - tcp_timestamps

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Kuniyuki Iwashima 2022-07-18 10:26:44 -07:00 committed by David S. Miller
parent 3d72bb4188
commit 3666f666e9
5 changed files with 16 additions and 16 deletions
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6
drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_cm.c
View file

@ -1236,8 +1236,8 @@ static struct sock *chtls_recv_sock(struct sock *lsk,
csk->sndbuf = newsk->sk_sndbuf;
csk->smac_idx = ((struct port_info *)netdev_priv(ndev))->smt_idx;
RCV_WSCALE(tp) = select_rcv_wscale(tcp_full_space(newsk),
sock_net(newsk)->
ipv4.sysctl_tcp_window_scaling,
READ_ONCE(sock_net(newsk)->
ipv4.sysctl_tcp_window_scaling),
tp->window_clamp);
neigh_release(n);
inet_inherit_port(&tcp_hashinfo, lsk, newsk);
@ -1384,7 +1384,7 @@ static void chtls_pass_accept_request(struct sock *sk,
#endif
}
if (req->tcpopt.wsf <= 14 &&
sock_net(sk)->ipv4.sysctl_tcp_window_scaling) {
READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_window_scaling)) {
inet_rsk(oreq)->wscale_ok = 1;
inet_rsk(oreq)->snd_wscale = req->tcpopt.wsf;
}

4
net/core/secure_seq.c
View file

@ -64,7 +64,7 @@ u32 secure_tcpv6_ts_off(const struct net *net,
.daddr = *(struct in6_addr *)daddr,
};
if (net->ipv4.sysctl_tcp_timestamps != 1)
if (READ_ONCE(net->ipv4.sysctl_tcp_timestamps) != 1)
return 0;
ts_secret_init();
@ -120,7 +120,7 @@ EXPORT_SYMBOL(secure_ipv6_port_ephemeral);
#ifdef CONFIG_INET
u32 secure_tcp_ts_off(const struct net *net, __be32 saddr, __be32 daddr)
{
if (net->ipv4.sysctl_tcp_timestamps != 1)
if (READ_ONCE(net->ipv4.sysctl_tcp_timestamps) != 1)
return 0;
ts_secret_init();

6
net/ipv4/syncookies.c
View file

@ -247,12 +247,12 @@ bool cookie_timestamp_decode(const struct net *net,
return true;
}
if (!net->ipv4.sysctl_tcp_timestamps)
if (!READ_ONCE(net->ipv4.sysctl_tcp_timestamps))
return false;
tcp_opt->sack_ok = (options & TS_OPT_SACK) ? TCP_SACK_SEEN : 0;
if (tcp_opt->sack_ok && !net->ipv4.sysctl_tcp_sack)
if (tcp_opt->sack_ok && !READ_ONCE(net->ipv4.sysctl_tcp_sack))
return false;
if ((options & TS_OPT_WSCALE_MASK) == TS_OPT_WSCALE_MASK)
@ -261,7 +261,7 @@ bool cookie_timestamp_decode(const struct net *net,
tcp_opt->wscale_ok = 1;
tcp_opt->snd_wscale = options & TS_OPT_WSCALE_MASK;
return net->ipv4.sysctl_tcp_window_scaling != 0;
return READ_ONCE(net->ipv4.sysctl_tcp_window_scaling) != 0;
}
EXPORT_SYMBOL(cookie_timestamp_decode);

6
net/ipv4/tcp_input.c
View file

@ -4060,7 +4060,7 @@ void tcp_parse_options(const struct net *net,
break;
case TCPOPT_WINDOW:
if (opsize == TCPOLEN_WINDOW && th->syn &&
!estab && net->ipv4.sysctl_tcp_window_scaling) {
!estab && READ_ONCE(net->ipv4.sysctl_tcp_window_scaling)) {
__u8 snd_wscale = *(__u8 *)ptr;
opt_rx->wscale_ok = 1;
if (snd_wscale > TCP_MAX_WSCALE) {
@ -4076,7 +4076,7 @@ void tcp_parse_options(const struct net *net,
case TCPOPT_TIMESTAMP:
if ((opsize == TCPOLEN_TIMESTAMP) &&
((estab && opt_rx->tstamp_ok) ||
(!estab && net->ipv4.sysctl_tcp_timestamps))) {
(!estab && READ_ONCE(net->ipv4.sysctl_tcp_timestamps)))) {
opt_rx->saw_tstamp = 1;
opt_rx->rcv_tsval = get_unaligned_be32(ptr);
opt_rx->rcv_tsecr = get_unaligned_be32(ptr + 4);
@ -4084,7 +4084,7 @@ void tcp_parse_options(const struct net *net,
break;
case TCPOPT_SACK_PERM:
if (opsize == TCPOLEN_SACK_PERM && th->syn &&
!estab && net->ipv4.sysctl_tcp_sack) {
!estab && READ_ONCE(net->ipv4.sysctl_tcp_sack)) {
opt_rx->sack_ok = TCP_SACK_SEEN;
tcp_sack_reset(opt_rx);
}

10
net/ipv4/tcp_output.c
View file

@ -791,18 +791,18 @@ static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb,
opts->mss = tcp_advertise_mss(sk);
remaining -= TCPOLEN_MSS_ALIGNED;
if (likely(sock_net(sk)->ipv4.sysctl_tcp_timestamps && !*md5)) {
if (likely(READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_timestamps) && !*md5)) {
opts->options |= OPTION_TS;
opts->tsval = tcp_skb_timestamp(skb) + tp->tsoffset;
opts->tsecr = tp->rx_opt.ts_recent;
remaining -= TCPOLEN_TSTAMP_ALIGNED;
}
if (likely(sock_net(sk)->ipv4.sysctl_tcp_window_scaling)) {
if (likely(READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_window_scaling))) {
opts->ws = tp->rx_opt.rcv_wscale;
opts->options |= OPTION_WSCALE;
remaining -= TCPOLEN_WSCALE_ALIGNED;
}
if (likely(sock_net(sk)->ipv4.sysctl_tcp_sack)) {
if (likely(READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_sack))) {
opts->options |= OPTION_SACK_ADVERTISE;
if (unlikely(!(OPTION_TS & opts->options)))
remaining -= TCPOLEN_SACKPERM_ALIGNED;
@ -3647,7 +3647,7 @@ static void tcp_connect_init(struct sock *sk)
* See tcp_input.c:tcp_rcv_state_process case TCP_SYN_SENT.
*/
tp->tcp_header_len = sizeof(struct tcphdr);
if (sock_net(sk)->ipv4.sysctl_tcp_timestamps)
if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_timestamps))
tp->tcp_header_len += TCPOLEN_TSTAMP_ALIGNED;
#ifdef CONFIG_TCP_MD5SIG
@ -3683,7 +3683,7 @@ static void tcp_connect_init(struct sock *sk)
tp->advmss - (tp->rx_opt.ts_recent_stamp ? tp->tcp_header_len - sizeof(struct tcphdr) : 0),
&tp->rcv_wnd,
&tp->window_clamp,
sock_net(sk)->ipv4.sysctl_tcp_window_scaling,
READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_window_scaling),
&rcv_wscale,
rcv_wnd);