[PATCH v1 net 00/15] sysctl: Fix data-races around ipv4_net_table (Round 1).

[PATCH v1 net 00/15] sysctl: Fix data-races around ipv4_net_table (Round 1).

[Kuniyuki Iwashima]

This series fixes data-races around the first 13 knobs and
nexthop_compat_mode in ipv4_net_table.

I will post another patch for three early_demux knobs later,
so the next round will start from ip_default_ttl.


Kuniyuki Iwashima (15):
  sysctl: Fix data-races in proc_dou8vec_minmax().
  sysctl: Fix data-races in proc_dointvec_ms_jiffies().
  tcp: Fix a data-race around sysctl_max_tw_buckets.
  icmp: Fix a data-race around sysctl_icmp_echo_ignore_all.
  icmp: Fix data-races around sysctl_icmp_echo_enable_probe.
  icmp: Fix a data-race around sysctl_icmp_echo_ignore_broadcasts.
  icmp: Fix a data-race around sysctl_icmp_ignore_bogus_error_responses.
  icmp: Fix a data-race around sysctl_icmp_errors_use_inbound_ifaddr.
  icmp: Fix a data-race around sysctl_icmp_ratelimit.
  icmp: Fix a data-race around sysctl_icmp_ratemask.
  raw: Fix a data-race around sysctl_raw_l3mdev_accept.
  tcp: Fix data-races around sysctl_tcp_ecn.
  tcp: Fix a data-race around sysctl_tcp_ecn_fallback.
  ipv4: Fix data-races around sysctl_ip_dynaddr.
  nexthop: Fix data-races around nexthop_compat_mode.

 Documentation/networking/ip-sysctl.rst            |  2 +-
 .../chelsio/inline_crypto/chtls/chtls_cm.c        |  2 +-
 include/net/raw.h                                 |  2 +-
 kernel/sysctl.c                                   | 12 ++++++------
 net/ipv4/af_inet.c                                |  4 ++--
 net/ipv4/fib_semantics.c                          |  2 +-
 net/ipv4/icmp.c                                   | 15 ++++++++-------
 net/ipv4/inet_timewait_sock.c                     |  3 ++-
 net/ipv4/nexthop.c                                |  5 +++--
 net/ipv4/syncookies.c                             |  2 +-
 net/ipv4/sysctl_net_ipv4.c                        | 12 ++++++++++++
 net/ipv4/tcp_input.c                              |  2 +-
 net/ipv4/tcp_output.c                             |  4 ++--
 net/ipv6/icmp.c                                   |  2 +-
 net/ipv6/route.c                                  |  2 +-
 15 files changed, 43 insertions(+), 28 deletions(-)

-- 
2.30.2

[PATCH v1 net 01/15] sysctl: Fix data-races in proc_dou8vec_minmax().

[Kuniyuki Iwashima]

A sysctl variable is accessed concurrently, and there is always a chance
of data-race.  So, all readers and writers need some basic protection to
avoid load/store-tearing.

This patch changes proc_dou8vec_minmax() to use READ_ONCE() and
WRITE_ONCE() internally to fix data-races on the sysctl side.  For now,
proc_dou8vec_minmax() itself is tolerant to a data-race, but we still
need to add annotations on the other subsystem's side.

Fixes: cb9444130662 ("sysctl: add proc_dou8vec_minmax()")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
 kernel/sysctl.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index bf9383d17e1b..b016d68da08a 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1007,13 +1007,13 @@ int proc_dou8vec_minmax(struct ctl_table *table, int write,
 
 	tmp.maxlen = sizeof(val);
 	tmp.data = &val;
-	val = *data;
+	val = READ_ONCE(*data);
 	res = do_proc_douintvec(&tmp, write, buffer, lenp, ppos,
 				do_proc_douintvec_minmax_conv, &param);
 	if (res)
 		return res;
 	if (write)
-		*data = val;
+		WRITE_ONCE(*data, val);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(proc_dou8vec_minmax);
-- 
2.30.2

[PATCH v1 net 02/15] sysctl: Fix data-races in proc_dointvec_ms_jiffies().

[Kuniyuki Iwashima]

A sysctl variable is accessed concurrently, and there is always a chance
of data-race.  So, all readers and writers need some basic protection to
avoid load/store-tearing.

This patch changes proc_dointvec_ms_jiffies() to use READ_ONCE() and
WRITE_ONCE() internally to fix data-races on the sysctl side.  For now,
proc_dointvec_ms_jiffies() itself is tolerant to a data-race, but we still
need to add annotations on the other subsystem's side.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
 kernel/sysctl.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index b016d68da08a..d99bc3945445 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1224,9 +1224,9 @@ static int do_proc_dointvec_ms_jiffies_conv(bool *negp, unsigned long *lvalp,
 
 		if (jif > INT_MAX)
 			return 1;
-		*valp = (int)jif;
+		WRITE_ONCE(*valp, (int)jif);
 	} else {
-		int val = *valp;
+		int val = READ_ONCE(*valp);
 		unsigned long lval;
 		if (val < 0) {
 			*negp = true;
@@ -1294,8 +1294,8 @@ int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
  * @ppos: the current position in the file
  *
  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
- * values from/to the user buffer, treated as an ASCII string. 
- * The values read are assumed to be in 1/1000 seconds, and 
+ * values from/to the user buffer, treated as an ASCII string.
+ * The values read are assumed to be in 1/1000 seconds, and
  * are converted into jiffies.
  *
  * Returns 0 on success.
-- 
2.30.2

[PATCH v1 net 03/15] tcp: Fix a data-race around sysctl_max_tw_buckets.

[Kuniyuki Iwashima]

While reading sysctl_max_tw_buckets, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
 net/ipv4/inet_timewait_sock.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index 0ec501845cb3..47ccc343c9fb 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -156,7 +156,8 @@ struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
 {
 	struct inet_timewait_sock *tw;
 
-	if (refcount_read(&dr->tw_refcount) - 1 >= dr->sysctl_max_tw_buckets)
+	if (refcount_read(&dr->tw_refcount) - 1 >=
+	    READ_ONCE(dr->sysctl_max_tw_buckets))
 		return NULL;
 
 	tw = kmem_cache_alloc(sk->sk_prot_creator->twsk_prot->twsk_slab,
-- 
2.30.2

[PATCH v1 net 04/15] icmp: Fix a data-race around sysctl_icmp_echo_ignore_all.

[Kuniyuki Iwashima]

While reading sysctl_icmp_echo_ignore_all, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
 net/ipv4/icmp.c            | 2 +-
 net/ipv4/sysctl_net_ipv4.c | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 0f9e61d29f73..1df4aae310e0 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -993,7 +993,7 @@ static enum skb_drop_reason icmp_echo(struct sk_buff *skb)
 
 	net = dev_net(skb_dst(skb)->dev);
 	/* should there be an ICMP stat for ignored echos? */
-	if (net->ipv4.sysctl_icmp_echo_ignore_all)
+	if (READ_ONCE(net->ipv4.sysctl_icmp_echo_ignore_all))
 		return SKB_NOT_DROPPED_YET;
 
 	icmp_param.data.icmph	   = *icmp_hdr(skb);
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index cd448cdd3b38..64682a01914a 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -599,6 +599,8 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(u8),
 		.mode		= 0644,
 		.proc_handler	= proc_dou8vec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE
 	},
 	{
 		.procname	= "icmp_echo_enable_probe",
-- 
2.30.2

[PATCH v1 net 05/15] icmp: Fix data-races around sysctl_icmp_echo_enable_probe.

[Kuniyuki Iwashima]

While reading sysctl_icmp_echo_enable_probe, it can be changed
concurrently.  Thus, we need to add READ_ONCE() to its readers.

Fixes: d329ea5bd884 ("icmp: add response to RFC 8335 PROBE messages")
Fixes: 1fd07f33c3ea ("ipv6: ICMPV6: add response to ICMPV6 RFC 8335 PROBE messages")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
CC: Andreas Roeseler <andreas.a.roeseler@gmail.com>
CC: Willem de Bruijn <willemb@google.com>
---
 net/ipv4/icmp.c | 2 +-
 net/ipv6/icmp.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 1df4aae310e0..c406e324c594 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -1028,7 +1028,7 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr)
 	u16 ident_len;
 	u8 status;
 
-	if (!net->ipv4.sysctl_icmp_echo_enable_probe)
+	if (!READ_ONCE(net->ipv4.sysctl_icmp_echo_enable_probe))
 		return false;
 
 	/* We currently only support probing interfaces on the proxy node
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index 61770220774e..9d92d51c4757 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -925,7 +925,7 @@ static int icmpv6_rcv(struct sk_buff *skb)
 		break;
 	case ICMPV6_EXT_ECHO_REQUEST:
 		if (!net->ipv6.sysctl.icmpv6_echo_ignore_all &&
-		    net->ipv4.sysctl_icmp_echo_enable_probe)
+		    READ_ONCE(net->ipv4.sysctl_icmp_echo_enable_probe))
 			icmpv6_echo_reply(skb);
 		break;
 
-- 
2.30.2

[PATCH v1 net 06/15] icmp: Fix a data-race around sysctl_icmp_echo_ignore_broadcasts.

[Kuniyuki Iwashima]

While reading sysctl_icmp_echo_ignore_broadcasts, it can be changed
concurrently.  Thus, we need to add READ_ONCE() to its reader.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
 net/ipv4/icmp.c            | 2 +-
 net/ipv4/sysctl_net_ipv4.c | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index c406e324c594..4b1d84d3feaa 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -1249,7 +1249,7 @@ int icmp_rcv(struct sk_buff *skb)
 		 */
 		if ((icmph->type == ICMP_ECHO ||
 		     icmph->type == ICMP_TIMESTAMP) &&
-		    net->ipv4.sysctl_icmp_echo_ignore_broadcasts) {
+		    READ_ONCE(net->ipv4.sysctl_icmp_echo_ignore_broadcasts)) {
 			reason = SKB_DROP_REASON_INVALID_PROTO;
 			goto error;
 		}
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 64682a01914a..cb53476a292e 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -617,6 +617,8 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(u8),
 		.mode		= 0644,
 		.proc_handler	= proc_dou8vec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE
 	},
 	{
 		.procname	= "icmp_ignore_bogus_error_responses",
-- 
2.30.2

[PATCH v1 net 07/15] icmp: Fix a data-race around sysctl_icmp_ignore_bogus_error_responses.

[Kuniyuki Iwashima]

While reading sysctl_icmp_ignore_bogus_error_responses, it can be changed
concurrently.  Thus, we need to add READ_ONCE() to its reader.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
 net/ipv4/icmp.c            | 2 +-
 net/ipv4/sysctl_net_ipv4.c | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 4b1d84d3feaa..0c01696c5584 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -933,7 +933,7 @@ static enum skb_drop_reason icmp_unreach(struct sk_buff *skb)
 	 *	get the other vendor to fix their kit.
 	 */
 
-	if (!net->ipv4.sysctl_icmp_ignore_bogus_error_responses &&
+	if (!READ_ONCE(net->ipv4.sysctl_icmp_ignore_bogus_error_responses) &&
 	    inet_addr_type_dev_table(net, skb->dev, iph->daddr) == RTN_BROADCAST) {
 		net_warn_ratelimited("%pI4 sent an invalid ICMP type %u, code %u error to a broadcast: %pI4 on %s\n",
 				     &ip_hdr(skb)->saddr,
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index cb53476a292e..3122e652f3c3 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -626,6 +626,8 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(u8),
 		.mode		= 0644,
 		.proc_handler	= proc_dou8vec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE
 	},
 	{
 		.procname	= "icmp_errors_use_inbound_ifaddr",
-- 
2.30.2

[PATCH v1 net 08/15] icmp: Fix a data-race around sysctl_icmp_errors_use_inbound_ifaddr.

[Kuniyuki Iwashima]

While reading sysctl_icmp_errors_use_inbound_ifaddr, it can be changed
concurrently.  Thus, we need to add READ_ONCE() to its reader.

Fixes: 1c2fb7f93cb2 ("[IPV4]: Sysctl configurable icmp error source address.")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
CC: J. Simonetti <jeroen@simonetti.nl>
---
 net/ipv4/icmp.c            | 2 +-
 net/ipv4/sysctl_net_ipv4.c | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 0c01696c5584..a49b68d6b969 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -693,7 +693,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info,
 
 		rcu_read_lock();
 		if (rt_is_input_route(rt) &&
-		    net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr)
+		    READ_ONCE(net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr))
 			dev = dev_get_by_index_rcu(net, inet_iif(skb_in));
 
 		if (dev)
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 3122e652f3c3..66159d49a575 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -635,6 +635,8 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(u8),
 		.mode		= 0644,
 		.proc_handler	= proc_dou8vec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE
 	},
 	{
 		.procname	= "icmp_ratelimit",
-- 
2.30.2

[PATCH v1 net 09/15] icmp: Fix a data-race around sysctl_icmp_ratelimit.

[Kuniyuki Iwashima]

While reading sysctl_icmp_ratelimit, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
 net/ipv4/icmp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index a49b68d6b969..1d454cc41713 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -320,7 +320,8 @@ static bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt,
 
 	vif = l3mdev_master_ifindex(dst->dev);
 	peer = inet_getpeer_v4(net->ipv4.peers, fl4->daddr, vif, 1);
-	rc = inet_peer_xrlim_allow(peer, net->ipv4.sysctl_icmp_ratelimit);
+	rc = inet_peer_xrlim_allow(peer,
+				   READ_ONCE(net->ipv4.sysctl_icmp_ratelimit));
 	if (peer)
 		inet_putpeer(peer);
 out:
-- 
2.30.2

[PATCH v1 net 10/15] icmp: Fix a data-race around sysctl_icmp_ratemask.

[Kuniyuki Iwashima]

While reading sysctl_icmp_ratemask, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
 net/ipv4/icmp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 1d454cc41713..57c4f0d87a7a 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -282,7 +282,7 @@ static bool icmpv4_mask_allow(struct net *net, int type, int code)
 		return true;
 
 	/* Limit if icmp type is enabled in ratemask. */
-	if (!((1 << type) & net->ipv4.sysctl_icmp_ratemask))
+	if (!((1 << type) & READ_ONCE(net->ipv4.sysctl_icmp_ratemask)))
 		return true;
 
 	return false;
-- 
2.30.2

[PATCH v1 net 11/15] raw: Fix a data-race around sysctl_raw_l3mdev_accept.

[Kuniyuki Iwashima]

While reading sysctl_raw_l3mdev_accept, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.

Fixes: 6897445fb194 ("net: provide a sysctl raw_l3mdev_accept for raw socket lookup with VRFs")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
CC: Mike Manning <mmanning@vyatta.att-mail.com>
---
 include/net/raw.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/net/raw.h b/include/net/raw.h
index 8ad8df594853..c51a635671a7 100644
--- a/include/net/raw.h
+++ b/include/net/raw.h
@@ -75,7 +75,7 @@ static inline bool raw_sk_bound_dev_eq(struct net *net, int bound_dev_if,
 				       int dif, int sdif)
 {
 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
-	return inet_bound_dev_eq(!!net->ipv4.sysctl_raw_l3mdev_accept,
+	return inet_bound_dev_eq(READ_ONCE(net->ipv4.sysctl_raw_l3mdev_accept),
 				 bound_dev_if, dif, sdif);
 #else
 	return inet_bound_dev_eq(true, bound_dev_if, dif, sdif);
-- 
2.30.2

[PATCH v1 net 12/15] tcp: Fix data-races around sysctl_tcp_ecn.

[Kuniyuki Iwashima]

While reading sysctl_tcp_ecn, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its readers.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
CC: Ayush Sawal <ayush.sawal@chelsio.com>
---
 drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_cm.c | 2 +-
 net/ipv4/syncookies.c                                       | 2 +-
 net/ipv4/sysctl_net_ipv4.c                                  | 2 ++
 net/ipv4/tcp_input.c                                        | 2 +-
 net/ipv4/tcp_output.c                                       | 2 +-
 5 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_cm.c b/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_cm.c
index 4af5561cbfc5..7c760aa65540 100644
--- a/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_cm.c
+++ b/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_cm.c
@@ -1392,7 +1392,7 @@ static void chtls_pass_accept_request(struct sock *sk,
 	th_ecn = tcph->ece && tcph->cwr;
 	if (th_ecn) {
 		ect = !INET_ECN_is_not_ect(ip_dsfield);
-		ecn_ok = sock_net(sk)->ipv4.sysctl_tcp_ecn;
+		ecn_ok = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_ecn);
 		if ((!ect && ecn_ok) || tcp_ca_needs_ecn(sk))
 			inet_rsk(oreq)->ecn_ok = 1;
 	}
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index f33c31dd7366..b387c4835155 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -273,7 +273,7 @@ bool cookie_ecn_ok(const struct tcp_options_received *tcp_opt,
 	if (!ecn_ok)
 		return false;
 
-	if (net->ipv4.sysctl_tcp_ecn)
+	if (READ_ONCE(net->ipv4.sysctl_tcp_ecn))
 		return true;
 
 	return dst_feature(dst, RTAX_FEATURE_ECN);
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 66159d49a575..5e308c1715af 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -676,6 +676,8 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(u8),
 		.mode		= 0644,
 		.proc_handler	= proc_dou8vec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_TWO,
 	},
 	{
 		.procname	= "tcp_ecn_fallback",
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 2e2a9ece9af2..3ec4edc37313 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -6729,7 +6729,7 @@ static void tcp_ecn_create_request(struct request_sock *req,
 
 	ect = !INET_ECN_is_not_ect(TCP_SKB_CB(skb)->ip_dsfield);
 	ecn_ok_dst = dst_feature(dst, DST_FEATURE_ECN_MASK);
-	ecn_ok = net->ipv4.sysctl_tcp_ecn || ecn_ok_dst;
+	ecn_ok = READ_ONCE(net->ipv4.sysctl_tcp_ecn) || ecn_ok_dst;
 
 	if (((!ect || th->res1) && ecn_ok) || tcp_ca_needs_ecn(listen_sk) ||
 	    (ecn_ok_dst & DST_FEATURE_ECN_CA) ||
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 1c054431e358..3dc17551ce25 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -324,7 +324,7 @@ static void tcp_ecn_send_syn(struct sock *sk, struct sk_buff *skb)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 	bool bpf_needs_ecn = tcp_bpf_ca_needs_ecn(sk);
-	bool use_ecn = sock_net(sk)->ipv4.sysctl_tcp_ecn == 1 ||
+	bool use_ecn = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_ecn) == 1 ||
 		tcp_ca_needs_ecn(sk) || bpf_needs_ecn;
 
 	if (!use_ecn) {
-- 
2.30.2

[PATCH v1 net 13/15] tcp: Fix a data-race around sysctl_tcp_ecn_fallback.

[Kuniyuki Iwashima]

While reading sysctl_tcp_ecn_fallback, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.

Fixes: 492135557dc0 ("tcp: add rfc3168, section 6.1.1.1. fallback")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
CC: Daniel Borkmann <daniel@iogearbox.net>
CC: Florian Westphal <fw@strlen.de>
CC: Mirja Kühlewind <mirja.kuehlewind@tik.ee.ethz.ch>
CC: Brian Trammell <trammell@tik.ee.ethz.ch>
---
 net/ipv4/sysctl_net_ipv4.c | 2 ++
 net/ipv4/tcp_output.c      | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 5e308c1715af..108fd86f2718 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -685,6 +685,8 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(u8),
 		.mode		= 0644,
 		.proc_handler	= proc_dou8vec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 	{
 		.procname	= "ip_dynaddr",
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 3dc17551ce25..11aa0ab10bba 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -346,7 +346,7 @@ static void tcp_ecn_send_syn(struct sock *sk, struct sk_buff *skb)
 
 static void tcp_ecn_clear_syn(struct sock *sk, struct sk_buff *skb)
 {
-	if (sock_net(sk)->ipv4.sysctl_tcp_ecn_fallback)
+	if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_ecn_fallback))
 		/* tp->ecn_flags are cleared at a later point in time when
 		 * SYN ACK is ultimatively being received.
 		 */
-- 
2.30.2

[PATCH v1 net 14/15] ipv4: Fix data-races around sysctl_ip_dynaddr.

[Kuniyuki Iwashima]

While reading sysctl_ip_dynaddr, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its readers.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
 Documentation/networking/ip-sysctl.rst | 2 +-
 net/ipv4/af_inet.c                     | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index 0e58001f8580..b3a534ed0e7c 100644
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -1179,7 +1179,7 @@ ip_autobind_reuse - BOOLEAN
 	option should only be set by experts.
 	Default: 0
 
-ip_dynaddr - BOOLEAN
+ip_dynaddr - INTEGER
 	If set non-zero, enables support for dynamic addresses.
 	If set to a non-zero value larger than 1, a kernel log
 	message will be printed when dynamic address rewriting
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 93da9f783bec..ac67f6b4ec70 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1246,7 +1246,7 @@ static int inet_sk_reselect_saddr(struct sock *sk)
 	if (new_saddr == old_saddr)
 		return 0;
 
-	if (sock_net(sk)->ipv4.sysctl_ip_dynaddr > 1) {
+	if (READ_ONCE(sock_net(sk)->ipv4.sysctl_ip_dynaddr) > 1) {
 		pr_info("%s(): shifting inet->saddr from %pI4 to %pI4\n",
 			__func__, &old_saddr, &new_saddr);
 	}
@@ -1301,7 +1301,7 @@ int inet_sk_rebuild_header(struct sock *sk)
 		 * Other protocols have to map its equivalent state to TCP_SYN_SENT.
 		 * DCCP maps its DCCP_REQUESTING state to TCP_SYN_SENT. -acme
 		 */
-		if (!sock_net(sk)->ipv4.sysctl_ip_dynaddr ||
+		if (!READ_ONCE(sock_net(sk)->ipv4.sysctl_ip_dynaddr) ||
 		    sk->sk_state != TCP_SYN_SENT ||
 		    (sk->sk_userlocks & SOCK_BINDADDR_LOCK) ||
 		    (err = inet_sk_reselect_saddr(sk)) != 0)
-- 
2.30.2

[PATCH v1 net 15/15] nexthop: Fix data-races around nexthop_compat_mode.

[Kuniyuki Iwashima]

While reading nexthop_compat_mode, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its readers.

Fixes: 4f80116d3df3 ("net: ipv4: add sysctl for nexthop api compatibility mode")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
CC: Roopa Prabhu <roopa@cumulusnetworks.com>
---
 net/ipv4/fib_semantics.c | 2 +-
 net/ipv4/nexthop.c       | 5 +++--
 net/ipv6/route.c         | 2 +-
 3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index a57ba23571c9..16dbd5075284 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -1811,7 +1811,7 @@ int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
 			goto nla_put_failure;
 		if (nexthop_is_blackhole(fi->nh))
 			rtm->rtm_type = RTN_BLACKHOLE;
-		if (!fi->fib_net->ipv4.sysctl_nexthop_compat_mode)
+		if (!READ_ONCE(fi->fib_net->ipv4.sysctl_nexthop_compat_mode))
 			goto offload;
 	}
 
diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c
index e459a391e607..853a75a8fbaf 100644
--- a/net/ipv4/nexthop.c
+++ b/net/ipv4/nexthop.c
@@ -1858,7 +1858,7 @@ static void __remove_nexthop_fib(struct net *net, struct nexthop *nh)
 		/* __ip6_del_rt does a release, so do a hold here */
 		fib6_info_hold(f6i);
 		ipv6_stub->ip6_del_rt(net, f6i,
-				      !net->ipv4.sysctl_nexthop_compat_mode);
+				      !READ_ONCE(net->ipv4.sysctl_nexthop_compat_mode));
 	}
 }
 
@@ -2361,7 +2361,8 @@ static int insert_nexthop(struct net *net, struct nexthop *new_nh,
 	if (!rc) {
 		nh_base_seq_inc(net);
 		nexthop_notify(RTM_NEWNEXTHOP, new_nh, &cfg->nlinfo);
-		if (replace_notify && net->ipv4.sysctl_nexthop_compat_mode)
+		if (replace_notify &&
+		    READ_ONCE(net->ipv4.sysctl_nexthop_compat_mode))
 			nexthop_replace_notify(net, new_nh, &cfg->nlinfo);
 	}
 
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 828355710c57..916417944ec8 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -5741,7 +5741,7 @@ static int rt6_fill_node(struct net *net, struct sk_buff *skb,
 		if (nexthop_is_blackhole(rt->nh))
 			rtm->rtm_type = RTN_BLACKHOLE;
 
-		if (net->ipv4.sysctl_nexthop_compat_mode &&
+		if (READ_ONCE(net->ipv4.sysctl_nexthop_compat_mode) &&
 		    rt6_fill_node_nexthop(skb, rt->nh, &nh_flags) < 0)
 			goto nla_put_failure;
 
-- 
2.30.2

Re: [PATCH v1 net 00/15] sysctl: Fix data-races around ipv4_net_table (Round 1).

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net.git (master)
by David S. Miller <davem@davemloft.net>:

On Mon, 11 Jul 2022 17:15:18 -0700 you wrote:
> This series fixes data-races around the first 13 knobs and
> nexthop_compat_mode in ipv4_net_table.
> 
> I will post another patch for three early_demux knobs later,
> so the next round will start from ip_default_ttl.
> 
> 
> [...]

Here is the summary with links:
  - [v1,net,01/15] sysctl: Fix data-races in proc_dou8vec_minmax().
    https://git.kernel.org/netdev/net/c/7dee5d7747a6
  - [v1,net,02/15] sysctl: Fix data-races in proc_dointvec_ms_jiffies().
    https://git.kernel.org/netdev/net/c/7d1025e55978
  - [v1,net,03/15] tcp: Fix a data-race around sysctl_max_tw_buckets.
    https://git.kernel.org/netdev/net/c/6f605b57f378
  - [v1,net,04/15] icmp: Fix a data-race around sysctl_icmp_echo_ignore_all.
    https://git.kernel.org/netdev/net/c/bb7bb35a63b4
  - [v1,net,05/15] icmp: Fix data-races around sysctl_icmp_echo_enable_probe.
    https://git.kernel.org/netdev/net/c/4a2f7083cc6c
  - [v1,net,06/15] icmp: Fix a data-race around sysctl_icmp_echo_ignore_broadcasts.
    https://git.kernel.org/netdev/net/c/66484bb98ed2
  - [v1,net,07/15] icmp: Fix a data-race around sysctl_icmp_ignore_bogus_error_responses.
    https://git.kernel.org/netdev/net/c/b04f9b7e85c7
  - [v1,net,08/15] icmp: Fix a data-race around sysctl_icmp_errors_use_inbound_ifaddr.
    https://git.kernel.org/netdev/net/c/d2efabce81db
  - [v1,net,09/15] icmp: Fix a data-race around sysctl_icmp_ratelimit.
    https://git.kernel.org/netdev/net/c/2a4eb714841f
  - [v1,net,10/15] icmp: Fix a data-race around sysctl_icmp_ratemask.
    https://git.kernel.org/netdev/net/c/1ebcb25ad6fc
  - [v1,net,11/15] raw: Fix a data-race around sysctl_raw_l3mdev_accept.
    https://git.kernel.org/netdev/net/c/1dace014928e
  - [v1,net,12/15] tcp: Fix data-races around sysctl_tcp_ecn.
    https://git.kernel.org/netdev/net/c/4785a66702f0
  - [v1,net,13/15] tcp: Fix a data-race around sysctl_tcp_ecn_fallback.
    https://git.kernel.org/netdev/net/c/12b8d9ca7e67
  - [v1,net,14/15] ipv4: Fix data-races around sysctl_ip_dynaddr.
    https://git.kernel.org/netdev/net/c/e49e4aff7ec1
  - [v1,net,15/15] nexthop: Fix data-races around nexthop_compat_mode.
    https://git.kernel.org/netdev/net/c/bdf00bf24bef

You are awesome, thank you!
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