mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-12 13:55:32 +00:00
cgroup: fix cgroup_sk_alloc() for sk_clone_lock()
When we clone a socket in sk_clone_lock(), its sk_cgrp_data is copied, so the cgroup refcnt must be taken too. And, unlike the sk_alloc() path, sock_update_netprioidx() is not called here. Therefore, it is safe and necessary to grab the cgroup refcnt even when cgroup_sk_alloc is disabled. sk_clone_lock() is in BH context anyway, the in_interrupt() would terminate this function if called there. And for sk_alloc() skcd->val is always zero. So it's safe to factor out the code to make it more readable. The global variable 'cgroup_sk_alloc_disabled' is used to determine whether to take these reference counts. It is impossible to make the reference counting correct unless we save this bit of information in skcd->val. So, add a new bit there to record whether the socket has already taken the reference counts. This obviously relies on kmalloc() to align cgroup pointers to at least 4 bytes, ARCH_KMALLOC_MINALIGN is certainly larger than that. This bug seems to be introduced since the beginning, commitd979a39d72
("cgroup: duplicate cgroup reference when cloning sockets") tried to fix it but not compeletely. It seems not easy to trigger until the recent commit090e28b229
("netprio_cgroup: Fix unlimited memory leak of v2 cgroups") was merged. Fixes:bd1060a1d6
("sock, cgroup: add sock->sk_cgroup") Reported-by: Cameron Berkenpas <cam@neo-zeon.de> Reported-by: Peter Geis <pgwipeout@gmail.com> Reported-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com> Reported-by: Daniël Sonck <dsonck92@gmail.com> Reported-by: Zhang Qiang <qiang.zhang@windriver.com> Tested-by: Cameron Berkenpas <cam@neo-zeon.de> Tested-by: Peter Geis <pgwipeout@gmail.com> Tested-by: Thomas Lamprecht <t.lamprecht@proxmox.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Zefan Li <lizefan@huawei.com> Cc: Tejun Heo <tj@kernel.org> Cc: Roman Gushchin <guro@fb.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
parent
aea23c323d
commit
ad0f75e5f5
4 changed files with 27 additions and 16 deletions
|
@ -790,7 +790,8 @@ struct sock_cgroup_data {
|
|||
union {
|
||||
#ifdef __LITTLE_ENDIAN
|
||||
struct {
|
||||
u8 is_data;
|
||||
u8 is_data : 1;
|
||||
u8 no_refcnt : 1;
|
||||
u8 padding;
|
||||
u16 prioidx;
|
||||
u32 classid;
|
||||
|
@ -800,7 +801,8 @@ struct sock_cgroup_data {
|
|||
u32 classid;
|
||||
u16 prioidx;
|
||||
u8 padding;
|
||||
u8 is_data;
|
||||
u8 no_refcnt : 1;
|
||||
u8 is_data : 1;
|
||||
} __packed;
|
||||
#endif
|
||||
u64 val;
|
||||
|
|
|
@ -822,6 +822,7 @@ extern spinlock_t cgroup_sk_update_lock;
|
|||
|
||||
void cgroup_sk_alloc_disable(void);
|
||||
void cgroup_sk_alloc(struct sock_cgroup_data *skcd);
|
||||
void cgroup_sk_clone(struct sock_cgroup_data *skcd);
|
||||
void cgroup_sk_free(struct sock_cgroup_data *skcd);
|
||||
|
||||
static inline struct cgroup *sock_cgroup_ptr(struct sock_cgroup_data *skcd)
|
||||
|
@ -835,7 +836,7 @@ static inline struct cgroup *sock_cgroup_ptr(struct sock_cgroup_data *skcd)
|
|||
*/
|
||||
v = READ_ONCE(skcd->val);
|
||||
|
||||
if (v & 1)
|
||||
if (v & 3)
|
||||
return &cgrp_dfl_root.cgrp;
|
||||
|
||||
return (struct cgroup *)(unsigned long)v ?: &cgrp_dfl_root.cgrp;
|
||||
|
@ -847,6 +848,7 @@ static inline struct cgroup *sock_cgroup_ptr(struct sock_cgroup_data *skcd)
|
|||
#else /* CONFIG_CGROUP_DATA */
|
||||
|
||||
static inline void cgroup_sk_alloc(struct sock_cgroup_data *skcd) {}
|
||||
static inline void cgroup_sk_clone(struct sock_cgroup_data *skcd) {}
|
||||
static inline void cgroup_sk_free(struct sock_cgroup_data *skcd) {}
|
||||
|
||||
#endif /* CONFIG_CGROUP_DATA */
|
||||
|
|
|
@ -6439,18 +6439,8 @@ void cgroup_sk_alloc_disable(void)
|
|||
|
||||
void cgroup_sk_alloc(struct sock_cgroup_data *skcd)
|
||||
{
|
||||
if (cgroup_sk_alloc_disabled)
|
||||
return;
|
||||
|
||||
/* Socket clone path */
|
||||
if (skcd->val) {
|
||||
/*
|
||||
* We might be cloning a socket which is left in an empty
|
||||
* cgroup and the cgroup might have already been rmdir'd.
|
||||
* Don't use cgroup_get_live().
|
||||
*/
|
||||
cgroup_get(sock_cgroup_ptr(skcd));
|
||||
cgroup_bpf_get(sock_cgroup_ptr(skcd));
|
||||
if (cgroup_sk_alloc_disabled) {
|
||||
skcd->no_refcnt = 1;
|
||||
return;
|
||||
}
|
||||
|
||||
|
@ -6475,10 +6465,27 @@ void cgroup_sk_alloc(struct sock_cgroup_data *skcd)
|
|||
rcu_read_unlock();
|
||||
}
|
||||
|
||||
void cgroup_sk_clone(struct sock_cgroup_data *skcd)
|
||||
{
|
||||
if (skcd->val) {
|
||||
if (skcd->no_refcnt)
|
||||
return;
|
||||
/*
|
||||
* We might be cloning a socket which is left in an empty
|
||||
* cgroup and the cgroup might have already been rmdir'd.
|
||||
* Don't use cgroup_get_live().
|
||||
*/
|
||||
cgroup_get(sock_cgroup_ptr(skcd));
|
||||
cgroup_bpf_get(sock_cgroup_ptr(skcd));
|
||||
}
|
||||
}
|
||||
|
||||
void cgroup_sk_free(struct sock_cgroup_data *skcd)
|
||||
{
|
||||
struct cgroup *cgrp = sock_cgroup_ptr(skcd);
|
||||
|
||||
if (skcd->no_refcnt)
|
||||
return;
|
||||
cgroup_bpf_put(cgrp);
|
||||
cgroup_put(cgrp);
|
||||
}
|
||||
|
|
|
@ -1926,7 +1926,7 @@ struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority)
|
|||
/* sk->sk_memcg will be populated at accept() time */
|
||||
newsk->sk_memcg = NULL;
|
||||
|
||||
cgroup_sk_alloc(&newsk->sk_cgrp_data);
|
||||
cgroup_sk_clone(&newsk->sk_cgrp_data);
|
||||
|
||||
rcu_read_lock();
|
||||
filter = rcu_dereference(sk->sk_filter);
|
||||
|
|
Loading…
Reference in a new issue