| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20251022054004.2514876-3-kuniyu@google.com>
Date: Wed, 22 Oct 2025 05:39:46 +0000
From: Kuniyuki Iwashima <kuniyu@...gle.com>
To: "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, David Ahern <dsahern@...nel.org>
Cc: Simon Horman <horms@...nel.org>, Kuniyuki Iwashima <kuniyu@...gle.com>,
Kuniyuki Iwashima <kuni1840@...il.com>, netdev@...r.kernel.org
Subject: [PATCH v1 net-next 2/5] neighbour: Annotate access to neigh_parms fields.
NEIGH_VAR() is read locklessly in the fast path, and IPv6 ndisc uses
NEIGH_VAR_SET() locklessly.
The next patch will convert neightbl_dump_info() to RCU.
Let's annotate accesses to neigh_param with READ_ONCE() and WRITE_ONCE().
Note that ndisc_ifinfo_sysctl_change() uses &NEIGH_VAR() and we cannot
use '&' with READ_ONCE(), so NEIGH_VAR_PTR() is introduced.
Note also that NEIGH_VAR_INIT() does not need WRITE_ONCE() as it is before
parms is published. Also, the only user hippi_neigh_setup_dev() is no
longer called since commit e3804cbebb67 ("net: remove COMPAT_NET_DEV_OPS"),
which looks wrong, but probably no one uses HIPPI and RoadRunner.
Signed-off-by: Kuniyuki Iwashima <kuniyu@...gle.com>
---
include/net/neighbour.h | 15 ++++++++++++---
net/core/neighbour.c | 17 ++++++-----------
net/ipv6/ndisc.c | 8 ++++----
3 files changed, 22 insertions(+), 18 deletions(-)
diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index 4a30bd458c5a9..998ff9eccebb7 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -92,15 +92,17 @@ struct neigh_parms {
static inline void neigh_var_set(struct neigh_parms *p, int index, int val)
{
set_bit(index, p->data_state);
- p->data[index] = val;
+ WRITE_ONCE(p->data[index], val);
}
-#define NEIGH_VAR(p, attr) ((p)->data[NEIGH_VAR_ ## attr])
+#define __NEIGH_VAR(p, attr) ((p)->data[NEIGH_VAR_ ## attr])
+#define NEIGH_VAR(p, attr) READ_ONCE(__NEIGH_VAR(p, attr))
+#define NEIGH_VAR_PTR(p, attr) (&(__NEIGH_VAR(p, attr)))
/* In ndo_neigh_setup, NEIGH_VAR_INIT should be used.
* In other cases, NEIGH_VAR_SET should be used.
*/
-#define NEIGH_VAR_INIT(p, attr, val) (NEIGH_VAR(p, attr) = val)
+#define NEIGH_VAR_INIT(p, attr, val) (__NEIGH_VAR(p, attr) = val)
#define NEIGH_VAR_SET(p, attr, val) neigh_var_set(p, NEIGH_VAR_ ## attr, val)
static inline void neigh_parms_data_state_setall(struct neigh_parms *p)
@@ -378,6 +380,13 @@ struct net *neigh_parms_net(const struct neigh_parms *parms)
unsigned long neigh_rand_reach_time(unsigned long base);
+static inline void neigh_set_reach_time(struct neigh_parms *p)
+{
+ unsigned long base = NEIGH_VAR(p, BASE_REACHABLE_TIME);
+
+ WRITE_ONCE(p->reachable_time, neigh_rand_reach_time(base));
+}
+
void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
struct sk_buff *skb);
struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 56ce01db1bcb4..b08a9df31a15b 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -995,8 +995,7 @@ static void neigh_periodic_work(struct work_struct *work)
WRITE_ONCE(tbl->last_rand, jiffies);
list_for_each_entry(p, &tbl->parms_list, list)
- p->reachable_time =
- neigh_rand_reach_time(NEIGH_VAR(p, BASE_REACHABLE_TIME));
+ neigh_set_reach_time(p);
}
if (atomic_read(&tbl->entries) < READ_ONCE(tbl->gc_thresh1))
@@ -1749,8 +1748,7 @@ struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
if (p) {
p->tbl = tbl;
refcount_set(&p->refcnt, 1);
- p->reachable_time =
- neigh_rand_reach_time(NEIGH_VAR(p, BASE_REACHABLE_TIME));
+ neigh_set_reach_time(p);
p->qlen = 0;
netdev_hold(dev, &p->dev_tracker, GFP_KERNEL);
p->dev = dev;
@@ -1810,8 +1808,7 @@ void neigh_table_init(int index, struct neigh_table *tbl)
list_add(&tbl->parms.list, &tbl->parms_list);
write_pnet(&tbl->parms.net, &init_net);
refcount_set(&tbl->parms.refcnt, 1);
- tbl->parms.reachable_time =
- neigh_rand_reach_time(NEIGH_VAR(&tbl->parms, BASE_REACHABLE_TIME));
+ neigh_set_reach_time(&tbl->parms);
tbl->parms.qlen = 0;
tbl->stats = alloc_percpu(struct neigh_statistics);
@@ -2194,7 +2191,7 @@ static int neightbl_fill_parms(struct sk_buff *skb, struct neigh_parms *parms)
NEIGH_VAR(parms, MCAST_PROBES)) ||
nla_put_u32(skb, NDTPA_MCAST_REPROBES,
NEIGH_VAR(parms, MCAST_REPROBES)) ||
- nla_put_msecs(skb, NDTPA_REACHABLE_TIME, parms->reachable_time,
+ nla_put_msecs(skb, NDTPA_REACHABLE_TIME, READ_ONCE(parms->reachable_time),
NDTPA_PAD) ||
nla_put_msecs(skb, NDTPA_BASE_REACHABLE_TIME,
NEIGH_VAR(parms, BASE_REACHABLE_TIME), NDTPA_PAD) ||
@@ -2475,8 +2472,7 @@ static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh,
* only be effective after the next time neigh_periodic_work
* decides to recompute it (can be multiple minutes)
*/
- p->reachable_time =
- neigh_rand_reach_time(NEIGH_VAR(p, BASE_REACHABLE_TIME));
+ neigh_set_reach_time(p);
break;
case NDTPA_GC_STALETIME:
NEIGH_VAR_SET(p, GC_STALETIME,
@@ -3721,8 +3717,7 @@ static int neigh_proc_base_reachable_time(const struct ctl_table *ctl, int write
* only be effective after the next time neigh_periodic_work
* decides to recompute it
*/
- p->reachable_time =
- neigh_rand_reach_time(NEIGH_VAR(p, BASE_REACHABLE_TIME));
+ neigh_set_reach_time(p);
}
return ret;
}
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index f427e41e9c49b..59d17b6f06bfd 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -1449,7 +1449,7 @@ static enum skb_drop_reason ndisc_router_discovery(struct sk_buff *skb)
BASE_REACHABLE_TIME, rtime);
NEIGH_VAR_SET(in6_dev->nd_parms,
GC_STALETIME, 3 * rtime);
- in6_dev->nd_parms->reachable_time = neigh_rand_reach_time(rtime);
+ neigh_set_reach_time(in6_dev->nd_parms);
in6_dev->tstamp = jiffies;
send_ifinfo_notify = true;
}
@@ -1948,9 +1948,9 @@ int ndisc_ifinfo_sysctl_change(const struct ctl_table *ctl, int write, void *buf
ret = -1;
if (write && ret == 0 && dev && (idev = in6_dev_get(dev)) != NULL) {
- if (ctl->data == &NEIGH_VAR(idev->nd_parms, BASE_REACHABLE_TIME))
- idev->nd_parms->reachable_time =
- neigh_rand_reach_time(NEIGH_VAR(idev->nd_parms, BASE_REACHABLE_TIME));
+ if (ctl->data == NEIGH_VAR_PTR(idev->nd_parms, BASE_REACHABLE_TIME))
+ neigh_set_reach_time(idev->nd_parms);
+
WRITE_ONCE(idev->tstamp, jiffies);
inet6_ifinfo_notify(RTM_NEWLINK, idev);
in6_dev_put(idev);
--
2.51.0.915.g61a8936c21-goog
Powered by blists - more mailing lists