Commit f594d631 authored by Eric W. Biederman's avatar Eric W. Biederman Committed by David S. Miller
Browse files

tcp_memcontrol: Remove setting cgroup settings via sysctl 



The code is broken and does not constrain sysctl_tcp_mem as
tcp_update_limit does.  With the result that it allows the cgroup tcp
memory limits to be bypassed.

The semantics are broken as the settings are not per netns and are in a
per netns table, and instead looks at current.

Since the code is broken in both design and implementation and does not
implement the functionality for which it was written remove it.

Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent cd91cce6

include/net/tcp_memcontrol.h

+0 −1
Original line number Diff line number Diff line
@@ -14,5 +14,4 @@ struct tcp_memcontrol { 
struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg);

int tcp_init_cgroup(struct mem_cgroup *memcg, struct cgroup_subsys *ss);

void tcp_destroy_cgroup(struct mem_cgroup *memcg);

void tcp_prot_mem(struct mem_cgroup *memcg, long val, int idx);

#endif /* _TCP_MEMCG_H */

net/ipv4/sysctl_net_ipv4.c

+2 −37
Original line number Diff line number Diff line
@@ -204,45 +204,10 @@ static int ipv4_tcp_mem(struct ctl_table *ctl, int write, 
			   void __user *buffer, size_t *lenp,

			   loff_t *ppos)

{

	int ret;

	unsigned long vec[3];

	struct net *net = current->nsproxy->net_ns;

#ifdef CONFIG_MEMCG_KMEM

	struct mem_cgroup *memcg;

#endif



	struct ctl_table tmp = {

		.data = &vec,

		.maxlen = sizeof(vec),

		.mode = ctl->mode,

	};



	if (!write) {

		ctl->data = &net->ipv4.sysctl_tcp_mem;

	ctl->data = &current->nsproxy->net_ns->ipv4.sysctl_tcp_mem;

	return proc_doulongvec_minmax(ctl, write, buffer, lenp, ppos);

}



	ret = proc_doulongvec_minmax(&tmp, write, buffer, lenp, ppos);

	if (ret)

		return ret;



#ifdef CONFIG_MEMCG_KMEM

	rcu_read_lock();

	memcg = mem_cgroup_from_task(current);



	tcp_prot_mem(memcg, vec[0], 0);

	tcp_prot_mem(memcg, vec[1], 1);

	tcp_prot_mem(memcg, vec[2], 2);

	rcu_read_unlock();

#endif



	net->ipv4.sysctl_tcp_mem[0] = vec[0];

	net->ipv4.sysctl_tcp_mem[1] = vec[1];

	net->ipv4.sysctl_tcp_mem[2] = vec[2];



	return 0;

}



static int proc_tcp_fastopen_key(struct ctl_table *ctl, int write,

				 void __user *buffer, size_t *lenp,

				 loff_t *ppos)

net/ipv4/tcp_memcontrol.c

+0 −14
Original line number Diff line number Diff line
@@ -226,20 +226,6 @@ static int tcp_cgroup_reset(struct cgroup_subsys_state *css, unsigned int event) 
	return 0;

}



void tcp_prot_mem(struct mem_cgroup *memcg, long val, int idx)

{

	struct tcp_memcontrol *tcp;

	struct cg_proto *cg_proto;



	cg_proto = tcp_prot.proto_cgroup(memcg);

	if (!cg_proto)

		return;



	tcp = tcp_from_cgproto(cg_proto);



	tcp->tcp_prot_mem[idx] = val;

}



static struct cftype tcp_files[] = {

	{

		.name = "kmem.tcp.limit_in_bytes",

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