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tcp: annotate data-races around tw->tw_ts_recent and tw->tw_ts_recent_stamp 

JIRA: https://issues.redhat.com/browse/RHEL-9279
Upstream Status: commit 69e0b33a7fce

CS9 lacks both support for TCP Authentication option and usec
resolution for TCP timestamps.
Both features are out of scope, so do needed context fixups.
This change was added to reduce conflicts in the followup patch.

commit 69e0b33a7fce4d96649b9fa32e56b696921aa48e
Author: Eric Dumazet <edumazet@google.com>
Date:   Mon Jun 3 15:51:06 2024 +0000

    tcp: annotate data-races around tw->tw_ts_recent and tw->tw_ts_recent_stamp

    These fields can be read and written locklessly, add annotations
    around these minor races.

    Signed-off-by: Eric Dumazet <edumazet@google.com>
    Reviewed-by: Simon Horman <horms@kernel.org>
    Signed-off-by: David S. Miller <davem@davemloft.net>

Conflicts: net/ipv4/tcp_ipv4.c net/ipv6/tcp_ipv6.c

Signed-off-by: Florian Westphal <fwestpha@redhat.com>
This commit is contained in:
Florian Westphal 2024-08-21 16:55:22 +02:00
parent 903e29dd1d
commit 23f780623d
3 changed files with 23 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
net/ipv4/tcp_ipv4.c
View File

@ -111,6 +111,7 @@ int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
const struct inet_timewait_sock *tw = inet_twsk(sktw);
const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
struct tcp_sock *tp = tcp_sk(sk);
int ts_recent_stamp;
if (reuse == 2) {
/* Still does not detect *everything* that goes through
@ -149,9 +150,10 @@ int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
If TW bucket has been already destroyed we fall back to VJ's scheme
and use initial timestamp retrieved from peer table.
*/
if (tcptw->tw_ts_recent_stamp &&
ts_recent_stamp = READ_ONCE(tcptw->tw_ts_recent_stamp);
if (ts_recent_stamp &&
(!twp || (reuse && time_after32(ktime_get_seconds(),
tcptw->tw_ts_recent_stamp)))) {
ts_recent_stamp)))) {
/* inet_twsk_hashdance() sets sk_refcnt after putting twsk
* and releasing the bucket lock.
*/
@ -175,8 +177,8 @@ int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
if (!seq)
seq = 1;
WRITE_ONCE(tp->write_seq, seq);
tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
tp->rx_opt.ts_recent = READ_ONCE(tcptw->tw_ts_recent);
tp->rx_opt.ts_recent_stamp = ts_recent_stamp;
}
return 1;
@ -946,7 +948,7 @@ static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
tcp_time_stamp_raw() + tcptw->tw_ts_offset,
tcptw->tw_ts_recent,
READ_ONCE(tcptw->tw_ts_recent),
tw->tw_bound_dev_if,
tcp_twsk_md5_key(tcptw),
tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,

22
net/ipv4/tcp_minisocks.c
View File

@ -96,16 +96,18 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb,
struct tcp_options_received tmp_opt;
struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw);
bool paws_reject = false;
int ts_recent_stamp;
tmp_opt.saw_tstamp = 0;
if (th->doff > (sizeof(*th) >> 2) && tcptw->tw_ts_recent_stamp) {
ts_recent_stamp = READ_ONCE(tcptw->tw_ts_recent_stamp);
if (th->doff > (sizeof(*th) >> 2) && ts_recent_stamp) {
tcp_parse_options(twsk_net(tw), skb, &tmp_opt, 0, NULL);
if (tmp_opt.saw_tstamp) {
if (tmp_opt.rcv_tsecr)
tmp_opt.rcv_tsecr -= tcptw->tw_ts_offset;
tmp_opt.ts_recent = tcptw->tw_ts_recent;
tmp_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
tmp_opt.ts_recent = READ_ONCE(tcptw->tw_ts_recent);
tmp_opt.ts_recent_stamp = ts_recent_stamp;
paws_reject = tcp_paws_reject(&tmp_opt, th->rst);
}
}
@ -146,8 +148,10 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb,
tw->tw_substate = TCP_TIME_WAIT;
tcptw->tw_rcv_nxt = TCP_SKB_CB(skb)->end_seq;
if (tmp_opt.saw_tstamp) {
tcptw->tw_ts_recent_stamp = ktime_get_seconds();
tcptw->tw_ts_recent = tmp_opt.rcv_tsval;
WRITE_ONCE(tcptw->tw_ts_recent_stamp,
ktime_get_seconds());
WRITE_ONCE(tcptw->tw_ts_recent,
tmp_opt.rcv_tsval);
}
inet_twsk_reschedule(tw, TCP_TIMEWAIT_LEN);
@ -191,8 +195,10 @@ kill:
}
if (tmp_opt.saw_tstamp) {
tcptw->tw_ts_recent = tmp_opt.rcv_tsval;
tcptw->tw_ts_recent_stamp = ktime_get_seconds();
WRITE_ONCE(tcptw->tw_ts_recent,
tmp_opt.rcv_tsval);
WRITE_ONCE(tcptw->tw_ts_recent_stamp,
ktime_get_seconds());
}
inet_twsk_put(tw);
@ -219,7 +225,7 @@ kill:
if (th->syn && !th->rst && !th->ack && !paws_reject &&
(after(TCP_SKB_CB(skb)->seq, tcptw->tw_rcv_nxt) ||
(tmp_opt.saw_tstamp &&
(s32)(tcptw->tw_ts_recent - tmp_opt.rcv_tsval) < 0))) {
(s32)(READ_ONCE(tcptw->tw_ts_recent) - tmp_opt.rcv_tsval) < 0))) {
u32 isn = tcptw->tw_snd_nxt + 65535 + 2;
if (isn == 0)
isn++;

3
net/ipv6/tcp_ipv6.c
View File

@ -1094,7 +1094,8 @@ static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
tcp_time_stamp_raw() + tcptw->tw_ts_offset,
tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
READ_ONCE(tcptw->tw_ts_recent), tw->tw_bound_dev_if,
tcp_twsk_md5_key(tcptw),
tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel), tw->tw_priority,
tw->tw_txhash);