linux/include/net/net_namespace.h
Eric Dumazet 0cafd77dcd net: add a refcount tracker for kernel sockets
Commit ffa84b5ffb ("net: add netns refcount tracker to struct sock")
added a tracker to sockets, but did not track kernel sockets.

We still have syzbot reports hinting about netns being destroyed
while some kernel TCP sockets had not been dismantled.

This patch tracks kernel sockets, and adds a ref_tracker_dir_print()
call to net_free() right before the netns is freed.

Normally, each layer is responsible for properly releasing its
kernel sockets before last call to net_free().

This debugging facility is enabled with CONFIG_NET_NS_REFCNT_TRACKER=y

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Tested-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-10-24 11:04:43 +01:00

545 lines
13 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Operations on the network namespace
*/
#ifndef __NET_NET_NAMESPACE_H
#define __NET_NET_NAMESPACE_H
#include <linux/atomic.h>
#include <linux/refcount.h>
#include <linux/workqueue.h>
#include <linux/list.h>
#include <linux/sysctl.h>
#include <linux/uidgid.h>
#include <net/flow.h>
#include <net/netns/core.h>
#include <net/netns/mib.h>
#include <net/netns/unix.h>
#include <net/netns/packet.h>
#include <net/netns/ipv4.h>
#include <net/netns/ipv6.h>
#include <net/netns/nexthop.h>
#include <net/netns/ieee802154_6lowpan.h>
#include <net/netns/sctp.h>
#include <net/netns/netfilter.h>
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
#include <net/netns/conntrack.h>
#endif
#if IS_ENABLED(CONFIG_NF_FLOW_TABLE)
#include <net/netns/flow_table.h>
#endif
#include <net/netns/nftables.h>
#include <net/netns/xfrm.h>
#include <net/netns/mpls.h>
#include <net/netns/can.h>
#include <net/netns/xdp.h>
#include <net/netns/smc.h>
#include <net/netns/bpf.h>
#include <net/netns/mctp.h>
#include <net/net_trackers.h>
#include <linux/ns_common.h>
#include <linux/idr.h>
#include <linux/skbuff.h>
#include <linux/notifier.h>
struct user_namespace;
struct proc_dir_entry;
struct net_device;
struct sock;
struct ctl_table_header;
struct net_generic;
struct uevent_sock;
struct netns_ipvs;
struct bpf_prog;
#define NETDEV_HASHBITS 8
#define NETDEV_HASHENTRIES (1 << NETDEV_HASHBITS)
struct net {
/* First cache line can be often dirtied.
* Do not place here read-mostly fields.
*/
refcount_t passive; /* To decide when the network
* namespace should be freed.
*/
spinlock_t rules_mod_lock;
atomic_t dev_unreg_count;
unsigned int dev_base_seq; /* protected by rtnl_mutex */
int ifindex;
spinlock_t nsid_lock;
atomic_t fnhe_genid;
struct list_head list; /* list of network namespaces */
struct list_head exit_list; /* To linked to call pernet exit
* methods on dead net (
* pernet_ops_rwsem read locked),
* or to unregister pernet ops
* (pernet_ops_rwsem write locked).
*/
struct llist_node cleanup_list; /* namespaces on death row */
#ifdef CONFIG_KEYS
struct key_tag *key_domain; /* Key domain of operation tag */
#endif
struct user_namespace *user_ns; /* Owning user namespace */
struct ucounts *ucounts;
struct idr netns_ids;
struct ns_common ns;
struct ref_tracker_dir refcnt_tracker;
struct ref_tracker_dir notrefcnt_tracker; /* tracker for objects not
* refcounted against netns
*/
struct list_head dev_base_head;
struct proc_dir_entry *proc_net;
struct proc_dir_entry *proc_net_stat;
#ifdef CONFIG_SYSCTL
struct ctl_table_set sysctls;
#endif
struct sock *rtnl; /* rtnetlink socket */
struct sock *genl_sock;
struct uevent_sock *uevent_sock; /* uevent socket */
struct hlist_head *dev_name_head;
struct hlist_head *dev_index_head;
struct raw_notifier_head netdev_chain;
/* Note that @hash_mix can be read millions times per second,
* it is critical that it is on a read_mostly cache line.
*/
u32 hash_mix;
struct net_device *loopback_dev; /* The loopback */
/* core fib_rules */
struct list_head rules_ops;
struct netns_core core;
struct netns_mib mib;
struct netns_packet packet;
#if IS_ENABLED(CONFIG_UNIX)
struct netns_unix unx;
#endif
struct netns_nexthop nexthop;
struct netns_ipv4 ipv4;
#if IS_ENABLED(CONFIG_IPV6)
struct netns_ipv6 ipv6;
#endif
#if IS_ENABLED(CONFIG_IEEE802154_6LOWPAN)
struct netns_ieee802154_lowpan ieee802154_lowpan;
#endif
#if defined(CONFIG_IP_SCTP) || defined(CONFIG_IP_SCTP_MODULE)
struct netns_sctp sctp;
#endif
#ifdef CONFIG_NETFILTER
struct netns_nf nf;
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
struct netns_ct ct;
#endif
#if defined(CONFIG_NF_TABLES) || defined(CONFIG_NF_TABLES_MODULE)
struct netns_nftables nft;
#endif
#if IS_ENABLED(CONFIG_NF_FLOW_TABLE)
struct netns_ft ft;
#endif
#endif
#ifdef CONFIG_WEXT_CORE
struct sk_buff_head wext_nlevents;
#endif
struct net_generic __rcu *gen;
/* Used to store attached BPF programs */
struct netns_bpf bpf;
/* Note : following structs are cache line aligned */
#ifdef CONFIG_XFRM
struct netns_xfrm xfrm;
#endif
u64 net_cookie; /* written once */
#if IS_ENABLED(CONFIG_IP_VS)
struct netns_ipvs *ipvs;
#endif
#if IS_ENABLED(CONFIG_MPLS)
struct netns_mpls mpls;
#endif
#if IS_ENABLED(CONFIG_CAN)
struct netns_can can;
#endif
#ifdef CONFIG_XDP_SOCKETS
struct netns_xdp xdp;
#endif
#if IS_ENABLED(CONFIG_MCTP)
struct netns_mctp mctp;
#endif
#if IS_ENABLED(CONFIG_CRYPTO_USER)
struct sock *crypto_nlsk;
#endif
struct sock *diag_nlsk;
#if IS_ENABLED(CONFIG_SMC)
struct netns_smc smc;
#endif
} __randomize_layout;
#include <linux/seq_file_net.h>
/* Init's network namespace */
extern struct net init_net;
#ifdef CONFIG_NET_NS
struct net *copy_net_ns(unsigned long flags, struct user_namespace *user_ns,
struct net *old_net);
void net_ns_get_ownership(const struct net *net, kuid_t *uid, kgid_t *gid);
void net_ns_barrier(void);
struct ns_common *get_net_ns(struct ns_common *ns);
struct net *get_net_ns_by_fd(int fd);
#else /* CONFIG_NET_NS */
#include <linux/sched.h>
#include <linux/nsproxy.h>
static inline struct net *copy_net_ns(unsigned long flags,
struct user_namespace *user_ns, struct net *old_net)
{
if (flags & CLONE_NEWNET)
return ERR_PTR(-EINVAL);
return old_net;
}
static inline void net_ns_get_ownership(const struct net *net,
kuid_t *uid, kgid_t *gid)
{
*uid = GLOBAL_ROOT_UID;
*gid = GLOBAL_ROOT_GID;
}
static inline void net_ns_barrier(void) {}
static inline struct ns_common *get_net_ns(struct ns_common *ns)
{
return ERR_PTR(-EINVAL);
}
static inline struct net *get_net_ns_by_fd(int fd)
{
return ERR_PTR(-EINVAL);
}
#endif /* CONFIG_NET_NS */
extern struct list_head net_namespace_list;
struct net *get_net_ns_by_pid(pid_t pid);
#ifdef CONFIG_SYSCTL
void ipx_register_sysctl(void);
void ipx_unregister_sysctl(void);
#else
#define ipx_register_sysctl()
#define ipx_unregister_sysctl()
#endif
#ifdef CONFIG_NET_NS
void __put_net(struct net *net);
/* Try using get_net_track() instead */
static inline struct net *get_net(struct net *net)
{
refcount_inc(&net->ns.count);
return net;
}
static inline struct net *maybe_get_net(struct net *net)
{
/* Used when we know struct net exists but we
* aren't guaranteed a previous reference count
* exists. If the reference count is zero this
* function fails and returns NULL.
*/
if (!refcount_inc_not_zero(&net->ns.count))
net = NULL;
return net;
}
/* Try using put_net_track() instead */
static inline void put_net(struct net *net)
{
if (refcount_dec_and_test(&net->ns.count))
__put_net(net);
}
static inline
int net_eq(const struct net *net1, const struct net *net2)
{
return net1 == net2;
}
static inline int check_net(const struct net *net)
{
return refcount_read(&net->ns.count) != 0;
}
void net_drop_ns(void *);
#else
static inline struct net *get_net(struct net *net)
{
return net;
}
static inline void put_net(struct net *net)
{
}
static inline struct net *maybe_get_net(struct net *net)
{
return net;
}
static inline
int net_eq(const struct net *net1, const struct net *net2)
{
return 1;
}
static inline int check_net(const struct net *net)
{
return 1;
}
#define net_drop_ns NULL
#endif
static inline void __netns_tracker_alloc(struct net *net,
netns_tracker *tracker,
bool refcounted,
gfp_t gfp)
{
#ifdef CONFIG_NET_NS_REFCNT_TRACKER
ref_tracker_alloc(refcounted ? &net->refcnt_tracker :
&net->notrefcnt_tracker,
tracker, gfp);
#endif
}
static inline void netns_tracker_alloc(struct net *net, netns_tracker *tracker,
gfp_t gfp)
{
__netns_tracker_alloc(net, tracker, true, gfp);
}
static inline void __netns_tracker_free(struct net *net,
netns_tracker *tracker,
bool refcounted)
{
#ifdef CONFIG_NET_NS_REFCNT_TRACKER
ref_tracker_free(refcounted ? &net->refcnt_tracker :
&net->notrefcnt_tracker, tracker);
#endif
}
static inline struct net *get_net_track(struct net *net,
netns_tracker *tracker, gfp_t gfp)
{
get_net(net);
netns_tracker_alloc(net, tracker, gfp);
return net;
}
static inline void put_net_track(struct net *net, netns_tracker *tracker)
{
__netns_tracker_free(net, tracker, true);
put_net(net);
}
typedef struct {
#ifdef CONFIG_NET_NS
struct net *net;
#endif
} possible_net_t;
static inline void write_pnet(possible_net_t *pnet, struct net *net)
{
#ifdef CONFIG_NET_NS
pnet->net = net;
#endif
}
static inline struct net *read_pnet(const possible_net_t *pnet)
{
#ifdef CONFIG_NET_NS
return pnet->net;
#else
return &init_net;
#endif
}
/* Protected by net_rwsem */
#define for_each_net(VAR) \
list_for_each_entry(VAR, &net_namespace_list, list)
#define for_each_net_continue_reverse(VAR) \
list_for_each_entry_continue_reverse(VAR, &net_namespace_list, list)
#define for_each_net_rcu(VAR) \
list_for_each_entry_rcu(VAR, &net_namespace_list, list)
#ifdef CONFIG_NET_NS
#define __net_init
#define __net_exit
#define __net_initdata
#define __net_initconst
#else
#define __net_init __init
#define __net_exit __ref
#define __net_initdata __initdata
#define __net_initconst __initconst
#endif
int peernet2id_alloc(struct net *net, struct net *peer, gfp_t gfp);
int peernet2id(const struct net *net, struct net *peer);
bool peernet_has_id(const struct net *net, struct net *peer);
struct net *get_net_ns_by_id(const struct net *net, int id);
struct pernet_operations {
struct list_head list;
/*
* Below methods are called without any exclusive locks.
* More than one net may be constructed and destructed
* in parallel on several cpus. Every pernet_operations
* have to keep in mind all other pernet_operations and
* to introduce a locking, if they share common resources.
*
* The only time they are called with exclusive lock is
* from register_pernet_subsys(), unregister_pernet_subsys()
* register_pernet_device() and unregister_pernet_device().
*
* Exit methods using blocking RCU primitives, such as
* synchronize_rcu(), should be implemented via exit_batch.
* Then, destruction of a group of net requires single
* synchronize_rcu() related to these pernet_operations,
* instead of separate synchronize_rcu() for every net.
* Please, avoid synchronize_rcu() at all, where it's possible.
*
* Note that a combination of pre_exit() and exit() can
* be used, since a synchronize_rcu() is guaranteed between
* the calls.
*/
int (*init)(struct net *net);
void (*pre_exit)(struct net *net);
void (*exit)(struct net *net);
void (*exit_batch)(struct list_head *net_exit_list);
unsigned int *id;
size_t size;
};
/*
* Use these carefully. If you implement a network device and it
* needs per network namespace operations use device pernet operations,
* otherwise use pernet subsys operations.
*
* Network interfaces need to be removed from a dying netns _before_
* subsys notifiers can be called, as most of the network code cleanup
* (which is done from subsys notifiers) runs with the assumption that
* dev_remove_pack has been called so no new packets will arrive during
* and after the cleanup functions have been called. dev_remove_pack
* is not per namespace so instead the guarantee of no more packets
* arriving in a network namespace is provided by ensuring that all
* network devices and all sockets have left the network namespace
* before the cleanup methods are called.
*
* For the longest time the ipv4 icmp code was registered as a pernet
* device which caused kernel oops, and panics during network
* namespace cleanup. So please don't get this wrong.
*/
int register_pernet_subsys(struct pernet_operations *);
void unregister_pernet_subsys(struct pernet_operations *);
int register_pernet_device(struct pernet_operations *);
void unregister_pernet_device(struct pernet_operations *);
struct ctl_table;
#ifdef CONFIG_SYSCTL
int net_sysctl_init(void);
struct ctl_table_header *register_net_sysctl(struct net *net, const char *path,
struct ctl_table *table);
void unregister_net_sysctl_table(struct ctl_table_header *header);
#else
static inline int net_sysctl_init(void) { return 0; }
static inline struct ctl_table_header *register_net_sysctl(struct net *net,
const char *path, struct ctl_table *table)
{
return NULL;
}
static inline void unregister_net_sysctl_table(struct ctl_table_header *header)
{
}
#endif
static inline int rt_genid_ipv4(const struct net *net)
{
return atomic_read(&net->ipv4.rt_genid);
}
#if IS_ENABLED(CONFIG_IPV6)
static inline int rt_genid_ipv6(const struct net *net)
{
return atomic_read(&net->ipv6.fib6_sernum);
}
#endif
static inline void rt_genid_bump_ipv4(struct net *net)
{
atomic_inc(&net->ipv4.rt_genid);
}
extern void (*__fib6_flush_trees)(struct net *net);
static inline void rt_genid_bump_ipv6(struct net *net)
{
if (__fib6_flush_trees)
__fib6_flush_trees(net);
}
#if IS_ENABLED(CONFIG_IEEE802154_6LOWPAN)
static inline struct netns_ieee802154_lowpan *
net_ieee802154_lowpan(struct net *net)
{
return &net->ieee802154_lowpan;
}
#endif
/* For callers who don't really care about whether it's IPv4 or IPv6 */
static inline void rt_genid_bump_all(struct net *net)
{
rt_genid_bump_ipv4(net);
rt_genid_bump_ipv6(net);
}
static inline int fnhe_genid(const struct net *net)
{
return atomic_read(&net->fnhe_genid);
}
static inline void fnhe_genid_bump(struct net *net)
{
atomic_inc(&net->fnhe_genid);
}
#ifdef CONFIG_NET
void net_ns_init(void);
#else
static inline void net_ns_init(void) {}
#endif
#endif /* __NET_NET_NAMESPACE_H */