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Commit e20dd1b0 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Greg Kroah-Hartman
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igmp: Fix data-races around sysctl_igmp_qrv. 



[ Upstream commit 8ebcc62c738f68688ee7c6fec2efe5bc6d3d7e60 ]

While reading sysctl_igmp_qrv, 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.

  qrv ?: READ_ONCE(net->ipv4.sysctl_igmp_qrv);

Fixes: a9fe8e29 ("ipv4: implement igmp_qrv sysctl to tune igmp robustness variable")
Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 73e5a0b5

net/ipv4/igmp.c

+13 −11
Original line number Diff line number Diff line
@@ -829,7 +829,7 @@ static void igmp_ifc_event(struct in_device *in_dev) 
	struct net *net = dev_net(in_dev->dev);

	if (IGMP_V1_SEEN(in_dev) || IGMP_V2_SEEN(in_dev))

		return;

	WRITE_ONCE(in_dev->mr_ifc_count, in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv);

	WRITE_ONCE(in_dev->mr_ifc_count, in_dev->mr_qrv ?: READ_ONCE(net->ipv4.sysctl_igmp_qrv));

	igmp_ifc_start_timer(in_dev, 1);

}
@@ -1011,7 +1011,7 @@ static bool igmp_heard_query(struct in_device *in_dev, struct sk_buff *skb, 
		 * received value was zero, use the default or statically

		 * configured value.

		 */

		in_dev->mr_qrv = ih3->qrv ?: net->ipv4.sysctl_igmp_qrv;

		in_dev->mr_qrv = ih3->qrv ?: READ_ONCE(net->ipv4.sysctl_igmp_qrv);

		in_dev->mr_qi = IGMPV3_QQIC(ih3->qqic)*HZ ?: IGMP_QUERY_INTERVAL;



		/* RFC3376, 8.3. Query Response Interval:
@@ -1191,7 +1191,7 @@ static void igmpv3_add_delrec(struct in_device *in_dev, struct ip_mc_list *im, 
	pmc->interface = im->interface;

	in_dev_hold(in_dev);

	pmc->multiaddr = im->multiaddr;

	pmc->crcount = in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv;

	pmc->crcount = in_dev->mr_qrv ?: READ_ONCE(net->ipv4.sysctl_igmp_qrv);

	pmc->sfmode = im->sfmode;

	if (pmc->sfmode == MCAST_INCLUDE) {

		struct ip_sf_list *psf;
@@ -1242,9 +1242,11 @@ static void igmpv3_del_delrec(struct in_device *in_dev, struct ip_mc_list *im) 
			swap(im->tomb, pmc->tomb);

			swap(im->sources, pmc->sources);

			for (psf = im->sources; psf; psf = psf->sf_next)

				psf->sf_crcount = in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv;

				psf->sf_crcount = in_dev->mr_qrv ?:

					READ_ONCE(net->ipv4.sysctl_igmp_qrv);

		} else {

			im->crcount = in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv;

			im->crcount = in_dev->mr_qrv ?:

				READ_ONCE(net->ipv4.sysctl_igmp_qrv);

		}

		in_dev_put(pmc->interface);

		kfree_pmc(pmc);
@@ -1351,7 +1353,7 @@ static void igmp_group_added(struct ip_mc_list *im) 
	if (in_dev->dead)

		return;



	im->unsolicit_count = net->ipv4.sysctl_igmp_qrv;

	im->unsolicit_count = READ_ONCE(net->ipv4.sysctl_igmp_qrv);

	if (IGMP_V1_SEEN(in_dev) || IGMP_V2_SEEN(in_dev)) {

		spin_lock_bh(&im->lock);

		igmp_start_timer(im, IGMP_INITIAL_REPORT_DELAY);
@@ -1365,7 +1367,7 @@ static void igmp_group_added(struct ip_mc_list *im) 
	 * IN() to IN(A).

	 */

	if (im->sfmode == MCAST_EXCLUDE)

		im->crcount = in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv;

		im->crcount = in_dev->mr_qrv ?: READ_ONCE(net->ipv4.sysctl_igmp_qrv);



	igmp_ifc_event(in_dev);

#endif
@@ -1756,7 +1758,7 @@ static void ip_mc_reset(struct in_device *in_dev) 


	in_dev->mr_qi = IGMP_QUERY_INTERVAL;

	in_dev->mr_qri = IGMP_QUERY_RESPONSE_INTERVAL;

	in_dev->mr_qrv = net->ipv4.sysctl_igmp_qrv;

	in_dev->mr_qrv = READ_ONCE(net->ipv4.sysctl_igmp_qrv);

}

#else

static void ip_mc_reset(struct in_device *in_dev)
@@ -1890,7 +1892,7 @@ static int ip_mc_del1_src(struct ip_mc_list *pmc, int sfmode, 
#ifdef CONFIG_IP_MULTICAST

		if (psf->sf_oldin &&

		    !IGMP_V1_SEEN(in_dev) && !IGMP_V2_SEEN(in_dev)) {

			psf->sf_crcount = in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv;

			psf->sf_crcount = in_dev->mr_qrv ?: READ_ONCE(net->ipv4.sysctl_igmp_qrv);

			psf->sf_next = pmc->tomb;

			pmc->tomb = psf;

			rv = 1;
@@ -1954,7 +1956,7 @@ static int ip_mc_del_src(struct in_device *in_dev, __be32 *pmca, int sfmode, 
		/* filter mode change */

		pmc->sfmode = MCAST_INCLUDE;

#ifdef CONFIG_IP_MULTICAST

		pmc->crcount = in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv;

		pmc->crcount = in_dev->mr_qrv ?: READ_ONCE(net->ipv4.sysctl_igmp_qrv);

		WRITE_ONCE(in_dev->mr_ifc_count, pmc->crcount);

		for (psf = pmc->sources; psf; psf = psf->sf_next)

			psf->sf_crcount = 0;
@@ -2133,7 +2135,7 @@ static int ip_mc_add_src(struct in_device *in_dev, __be32 *pmca, int sfmode, 
#ifdef CONFIG_IP_MULTICAST

		/* else no filters; keep old mode for reports */



		pmc->crcount = in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv;

		pmc->crcount = in_dev->mr_qrv ?: READ_ONCE(net->ipv4.sysctl_igmp_qrv);

		WRITE_ONCE(in_dev->mr_ifc_count, pmc->crcount);

		for (psf = pmc->sources; psf; psf = psf->sf_next)

			psf->sf_crcount = 0;