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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Kuniyuki Iwashima <kuniyu@amazon.com>,
	"David S. Miller" <davem@davemloft.net>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 13/26] igmp: Fix data-races around sysctl_igmp_llm_reports.
Date: Wed, 27 Jul 2022 18:10:42 +0200	[thread overview]
Message-ID: <20220727160959.660499620@linuxfoundation.org> (raw)
In-Reply-To: <20220727160959.122591422@linuxfoundation.org>

From: Kuniyuki Iwashima <kuniyu@amazon.com>

[ Upstream commit f6da2267e71106474fbc0943dc24928b9cb79119 ]

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

This test can be packed into a helper, so such changes will be in the
follow-up series after net is merged into net-next.

  if (ipv4_is_local_multicast(pmc->multiaddr) &&
      !READ_ONCE(net->ipv4.sysctl_igmp_llm_reports))

Fixes: df2cf4a78e48 ("IGMP: Inhibit reports for local multicast groups")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/ipv4/igmp.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index 75f961425639..6e217424e0ff 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -474,7 +474,8 @@ static struct sk_buff *add_grec(struct sk_buff *skb, struct ip_mc_list *pmc,
 
 	if (pmc->multiaddr == IGMP_ALL_HOSTS)
 		return skb;
-	if (ipv4_is_local_multicast(pmc->multiaddr) && !net->ipv4.sysctl_igmp_llm_reports)
+	if (ipv4_is_local_multicast(pmc->multiaddr) &&
+	    !READ_ONCE(net->ipv4.sysctl_igmp_llm_reports))
 		return skb;
 
 	mtu = READ_ONCE(dev->mtu);
@@ -600,7 +601,7 @@ static int igmpv3_send_report(struct in_device *in_dev, struct ip_mc_list *pmc)
 			if (pmc->multiaddr == IGMP_ALL_HOSTS)
 				continue;
 			if (ipv4_is_local_multicast(pmc->multiaddr) &&
-			     !net->ipv4.sysctl_igmp_llm_reports)
+			    !READ_ONCE(net->ipv4.sysctl_igmp_llm_reports))
 				continue;
 			spin_lock_bh(&pmc->lock);
 			if (pmc->sfcount[MCAST_EXCLUDE])
@@ -743,7 +744,8 @@ static int igmp_send_report(struct in_device *in_dev, struct ip_mc_list *pmc,
 	if (type == IGMPV3_HOST_MEMBERSHIP_REPORT)
 		return igmpv3_send_report(in_dev, pmc);
 
-	if (ipv4_is_local_multicast(group) && !net->ipv4.sysctl_igmp_llm_reports)
+	if (ipv4_is_local_multicast(group) &&
+	    !READ_ONCE(net->ipv4.sysctl_igmp_llm_reports))
 		return 0;
 
 	if (type == IGMP_HOST_LEAVE_MESSAGE)
@@ -921,7 +923,8 @@ static bool igmp_heard_report(struct in_device *in_dev, __be32 group)
 
 	if (group == IGMP_ALL_HOSTS)
 		return false;
-	if (ipv4_is_local_multicast(group) && !net->ipv4.sysctl_igmp_llm_reports)
+	if (ipv4_is_local_multicast(group) &&
+	    !READ_ONCE(net->ipv4.sysctl_igmp_llm_reports))
 		return false;
 
 	rcu_read_lock();
@@ -1031,7 +1034,7 @@ static bool igmp_heard_query(struct in_device *in_dev, struct sk_buff *skb,
 		if (im->multiaddr == IGMP_ALL_HOSTS)
 			continue;
 		if (ipv4_is_local_multicast(im->multiaddr) &&
-		    !net->ipv4.sysctl_igmp_llm_reports)
+		    !READ_ONCE(net->ipv4.sysctl_igmp_llm_reports))
 			continue;
 		spin_lock_bh(&im->lock);
 		if (im->tm_running)
@@ -1272,7 +1275,8 @@ static void igmp_group_dropped(struct ip_mc_list *im)
 #ifdef CONFIG_IP_MULTICAST
 	if (im->multiaddr == IGMP_ALL_HOSTS)
 		return;
-	if (ipv4_is_local_multicast(im->multiaddr) && !net->ipv4.sysctl_igmp_llm_reports)
+	if (ipv4_is_local_multicast(im->multiaddr) &&
+	    !READ_ONCE(net->ipv4.sysctl_igmp_llm_reports))
 		return;
 
 	reporter = im->reporter;
@@ -1309,7 +1313,8 @@ static void igmp_group_added(struct ip_mc_list *im)
 #ifdef CONFIG_IP_MULTICAST
 	if (im->multiaddr == IGMP_ALL_HOSTS)
 		return;
-	if (ipv4_is_local_multicast(im->multiaddr) && !net->ipv4.sysctl_igmp_llm_reports)
+	if (ipv4_is_local_multicast(im->multiaddr) &&
+	    !READ_ONCE(net->ipv4.sysctl_igmp_llm_reports))
 		return;
 
 	if (in_dev->dead)
@@ -1621,7 +1626,7 @@ static void ip_mc_rejoin_groups(struct in_device *in_dev)
 		if (im->multiaddr == IGMP_ALL_HOSTS)
 			continue;
 		if (ipv4_is_local_multicast(im->multiaddr) &&
-		    !net->ipv4.sysctl_igmp_llm_reports)
+		    !READ_ONCE(net->ipv4.sysctl_igmp_llm_reports))
 			continue;
 
 		/* a failover is happening and switches
-- 
2.35.1




  parent reply	other threads:[~2022-07-27 16:22 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-27 16:10 [PATCH 4.9 00/26] 4.9.325-rc1 review Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 01/26] security,selinux,smack: kill security_task_wait hook Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 02/26] xen/gntdev: Ignore failure to unmap INVALID_GRANT_HANDLE Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 03/26] misc: rtsx_usb: fix use of dma mapped buffer for usb bulk transfer Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 04/26] misc: rtsx_usb: use separate command and response buffers Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 05/26] misc: rtsx_usb: set return value in rsp_buf alloc err path Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 06/26] xfrm: xfrm_policy: fix a possible double xfrm_pols_put() in xfrm_bundle_lookup() Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 07/26] power/reset: arm-versatile: Fix refcount leak in versatile_reboot_probe Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 08/26] perf/core: Fix data race between perf_event_set_output() and perf_mmap_close() Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 09/26] ip: Fix a data-race around sysctl_fwmark_reflect Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 10/26] tcp/dccp: Fix a data-race around sysctl_tcp_fwmark_accept Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 11/26] tcp: Fix a data-race around sysctl_tcp_probe_threshold Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 12/26] i2c: cadence: Change large transfer count reset logic to be unconditional Greg Kroah-Hartman
2022-07-27 16:10 ` Greg Kroah-Hartman [this message]
2022-07-27 16:10 ` [PATCH 4.9 14/26] igmp: Fix a data-race around sysctl_igmp_max_memberships Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 15/26] tcp: Fix a data-race around sysctl_tcp_notsent_lowat Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 16/26] be2net: Fix buffer overflow in be_get_module_eeprom Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 17/26] Revert "Revert "char/random: silence a lockdep splat with printk()"" Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 18/26] mm/mempolicy: fix uninit-value in mpol_rebind_policy() Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 19/26] bpf: Make sure mac_header was set before using it Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 20/26] ALSA: memalloc: Align buffer allocations in page size Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 21/26] tty: drivers/tty/, stop using tty_schedule_flip() Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 22/26] tty: the rest, " Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 23/26] tty: drop tty_schedule_flip() Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 24/26] tty: extract tty_flip_buffer_commit() from tty_flip_buffer_push() Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 25/26] tty: use new tty_insert_flip_string_and_push_buffer() in pty_write() Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 26/26] net: usb: ax88179_178a needs FLAG_SEND_ZLP Greg Kroah-Hartman
2022-07-27 22:18 ` [PATCH 4.9 00/26] 4.9.325-rc1 review Florian Fainelli
2022-07-28  9:42 ` Pavel Machek
2022-07-28 10:08 ` Naresh Kamboju
2022-07-28 14:52 ` Shuah Khan
2022-07-28 22:57 ` Guenter Roeck

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