BugLink: https://bugs.launchpad.net/bugs/1843463
[ Upstream commit
dbf47a2a094edf58983265e323ca4bdcdb58b5ee ]
Action sample doesn't properly handle psample_group pointer in overwrite
case. Following issues need to be fixed:
- In tcf_sample_init() function RCU_INIT_POINTER() is used to set
s->psample_group, even though we neither setting the pointer to NULL, nor
preventing concurrent readers from accessing the pointer in some way.
Use rcu_swap_protected() instead to safely reset the pointer.
- Old value of s->psample_group is not released or deallocated in any way,
which results resource leak. Use psample_group_put() on non-NULL value
obtained with rcu_swap_protected().
- The function psample_group_put() that released reference to struct
psample_group pointed by rcu-pointer s->psample_group doesn't respect rcu
grace period when deallocating it. Extend struct psample_group with rcu
head and use kfree_rcu when freeing it.
Fixes: 5c5670fae430 ("net/sched: Introduce sample tc action")
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
u32 group_num;
u32 refcount;
u32 seq;
u32 group_num;
u32 refcount;
u32 seq;
};
struct psample_group *psample_group_get(struct net *net, u32 group_num);
};
struct psample_group *psample_group_get(struct net *net, u32 group_num);
{
psample_group_notify(group, PSAMPLE_CMD_DEL_GROUP);
list_del(&group->list);
{
psample_group_notify(group, PSAMPLE_CMD_DEL_GROUP);
list_del(&group->list);
}
static struct psample_group *
}
static struct psample_group *
tcf_idr_release(*a, bind);
return -ENOMEM;
}
tcf_idr_release(*a, bind);
return -ENOMEM;
}
- RCU_INIT_POINTER(s->psample_group, psample_group);
+ rcu_swap_protected(s->psample_group, psample_group,
+ lockdep_is_held(&s->tcf_lock));
if (tb[TCA_SAMPLE_TRUNC_SIZE]) {
s->truncate = true;
s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]);
}
if (tb[TCA_SAMPLE_TRUNC_SIZE]) {
s->truncate = true;
s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]);
}
+ if (psample_group)
+ psample_group_put(psample_group);
if (ret == ACT_P_CREATED)
tcf_idr_insert(tn, *a);
return ret;
if (ret == ACT_P_CREATED)
tcf_idr_insert(tn, *a);
return ret;