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ipv4: igmp: annotate data-races in igmp_heard_query()

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Multiple cpus can run igmp_heard_query() concurrently.

Add missing READ_ONCE()/WRITE_ONCE() over following in_dev fields.

- mr_qrv
- mr_qi
- mr_qri
- mr_v1_seen
- mr_v2_seen

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: syzbot+ae9a171f239b14485310@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/69f38675.050a0220.3cbe47.0002.GAE@google.com
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260430164836.872079-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2026-04-30 16:48:36 +00:00 committed by Jakub Kicinski
parent 4b9e327991
commit c6bebaa744
1 changed files with 36 additions and 22 deletions
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58
net/ipv4/igmp.c
View File

@ -122,16 +122,29 @@
* contradict to specs provided this delay is small enough. * contradict to specs provided this delay is small enough.
*/ */
#define IGMP_V1_SEEN(in_dev) \ static bool IGMP_V1_SEEN(const struct in_device *in_dev)
(IPV4_DEVCONF_ALL_RO(dev_net(in_dev->dev), FORCE_IGMP_VERSION) == 1 || \ {
IN_DEV_CONF_GET((in_dev), FORCE_IGMP_VERSION) == 1 || \ unsigned long seen;
((in_dev)->mr_v1_seen && \
time_before(jiffies, (in_dev)->mr_v1_seen))) if (IPV4_DEVCONF_ALL_RO(dev_net(in_dev->dev), FORCE_IGMP_VERSION) == 1)
#define IGMP_V2_SEEN(in_dev) \ return true;
(IPV4_DEVCONF_ALL_RO(dev_net(in_dev->dev), FORCE_IGMP_VERSION) == 2 || \ if (IN_DEV_CONF_GET((in_dev), FORCE_IGMP_VERSION) == 1)
IN_DEV_CONF_GET((in_dev), FORCE_IGMP_VERSION) == 2 || \ return true;
((in_dev)->mr_v2_seen && \ seen = READ_ONCE(in_dev->mr_v1_seen);
time_before(jiffies, (in_dev)->mr_v2_seen))) return seen && time_before(jiffies, seen);
}
static bool IGMP_V2_SEEN(const struct in_device *in_dev)
{
unsigned long seen;
if (IPV4_DEVCONF_ALL_RO(dev_net(in_dev->dev), FORCE_IGMP_VERSION) == 2)
return true;
if (IN_DEV_CONF_GET((in_dev), FORCE_IGMP_VERSION) == 2)
return true;
seen = READ_ONCE(in_dev->mr_v2_seen);
return seen && time_before(jiffies, seen);
}
static int unsolicited_report_interval(struct in_device *in_dev) static int unsolicited_report_interval(struct in_device *in_dev)
{ {
@ -954,23 +967,21 @@ static bool igmp_heard_query(struct in_device *in_dev, struct sk_buff *skb,
int max_delay; int max_delay;
int mark = 0; int mark = 0;
struct net *net = dev_net(in_dev->dev); struct net *net = dev_net(in_dev->dev);
unsigned long seen;
if (len == 8) { if (len == 8) {
seen = jiffies + READ_ONCE(in_dev->mr_qrv) * READ_ONCE(in_dev->mr_qi) +
READ_ONCE(in_dev->mr_qri);
if (ih->code == 0) { if (ih->code == 0) {
/* Alas, old v1 router presents here. */ /* Alas, old v1 router presents here. */
max_delay = IGMP_QUERY_RESPONSE_INTERVAL; max_delay = IGMP_QUERY_RESPONSE_INTERVAL;
in_dev->mr_v1_seen = jiffies + WRITE_ONCE(in_dev->mr_v1_seen, seen);
(in_dev->mr_qrv * in_dev->mr_qi) +
in_dev->mr_qri;
group = 0; group = 0;
} else { } else {
/* v2 router present */ /* v2 router present */
max_delay = ih->code*(HZ/IGMP_TIMER_SCALE); max_delay = ih->code*(HZ/IGMP_TIMER_SCALE);
in_dev->mr_v2_seen = jiffies + WRITE_ONCE(in_dev->mr_v2_seen, seen);
(in_dev->mr_qrv * in_dev->mr_qi) +
in_dev->mr_qri;
} }
/* cancel the interface change timer */ /* cancel the interface change timer */
WRITE_ONCE(in_dev->mr_ifc_count, 0); WRITE_ONCE(in_dev->mr_ifc_count, 0);
@ -995,6 +1006,8 @@ static bool igmp_heard_query(struct in_device *in_dev, struct sk_buff *skb,
if (!max_delay) if (!max_delay)
max_delay = 1; /* can't mod w/ 0 */ max_delay = 1; /* can't mod w/ 0 */
} else { /* v3 */ } else { /* v3 */
unsigned long mr_qi;
if (!pskb_may_pull(skb, sizeof(struct igmpv3_query))) if (!pskb_may_pull(skb, sizeof(struct igmpv3_query)))
return true; return true;
@ -1015,15 +1028,16 @@ static bool igmp_heard_query(struct in_device *in_dev, struct sk_buff *skb,
* received value was zero, use the default or statically * received value was zero, use the default or statically
* configured value. * configured value.
*/ */
in_dev->mr_qrv = ih3->qrv ?: READ_ONCE(net->ipv4.sysctl_igmp_qrv); WRITE_ONCE(in_dev->mr_qrv,
in_dev->mr_qi = IGMPV3_QQIC(ih3->qqic)*HZ ?: IGMP_QUERY_INTERVAL; ih3->qrv ?: READ_ONCE(net->ipv4.sysctl_igmp_qrv));
mr_qi = IGMPV3_QQIC(ih3->qqic)*HZ ?: IGMP_QUERY_INTERVAL;
WRITE_ONCE(in_dev->mr_qi, mr_qi);
/* RFC3376, 8.3. Query Response Interval: /* RFC3376, 8.3. Query Response Interval:
* The number of seconds represented by the [Query Response * The number of seconds represented by the [Query Response
* Interval] must be less than the [Query Interval]. * Interval] must be less than the [Query Interval].
*/ */
if (in_dev->mr_qri >= in_dev->mr_qi) if (READ_ONCE(in_dev->mr_qri) >= mr_qi)
in_dev->mr_qri = (in_dev->mr_qi/HZ - 1)*HZ; WRITE_ONCE(in_dev->mr_qri, (mr_qi/HZ - 1) * HZ);
if (!group) { /* general query */ if (!group) { /* general query */
if (ih3->nsrcs) if (ih3->nsrcs)