cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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netclassid_cgroup.c (3288B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * net/core/netclassid_cgroup.c	Classid Cgroupfs Handling
      4 *
      5 * Authors:	Thomas Graf <tgraf@suug.ch>
      6 */
      7
      8#include <linux/slab.h>
      9#include <linux/cgroup.h>
     10#include <linux/fdtable.h>
     11#include <linux/sched/task.h>
     12
     13#include <net/cls_cgroup.h>
     14#include <net/sock.h>
     15
     16static inline struct cgroup_cls_state *css_cls_state(struct cgroup_subsys_state *css)
     17{
     18	return css ? container_of(css, struct cgroup_cls_state, css) : NULL;
     19}
     20
     21struct cgroup_cls_state *task_cls_state(struct task_struct *p)
     22{
     23	return css_cls_state(task_css_check(p, net_cls_cgrp_id,
     24					    rcu_read_lock_bh_held()));
     25}
     26EXPORT_SYMBOL_GPL(task_cls_state);
     27
     28static struct cgroup_subsys_state *
     29cgrp_css_alloc(struct cgroup_subsys_state *parent_css)
     30{
     31	struct cgroup_cls_state *cs;
     32
     33	cs = kzalloc(sizeof(*cs), GFP_KERNEL);
     34	if (!cs)
     35		return ERR_PTR(-ENOMEM);
     36
     37	return &cs->css;
     38}
     39
     40static int cgrp_css_online(struct cgroup_subsys_state *css)
     41{
     42	struct cgroup_cls_state *cs = css_cls_state(css);
     43	struct cgroup_cls_state *parent = css_cls_state(css->parent);
     44
     45	if (parent)
     46		cs->classid = parent->classid;
     47
     48	return 0;
     49}
     50
     51static void cgrp_css_free(struct cgroup_subsys_state *css)
     52{
     53	kfree(css_cls_state(css));
     54}
     55
     56/*
     57 * To avoid freezing of sockets creation for tasks with big number of threads
     58 * and opened sockets lets release file_lock every 1000 iterated descriptors.
     59 * New sockets will already have been created with new classid.
     60 */
     61
     62struct update_classid_context {
     63	u32 classid;
     64	unsigned int batch;
     65};
     66
     67#define UPDATE_CLASSID_BATCH 1000
     68
     69static int update_classid_sock(const void *v, struct file *file, unsigned n)
     70{
     71	struct update_classid_context *ctx = (void *)v;
     72	struct socket *sock = sock_from_file(file);
     73
     74	if (sock)
     75		sock_cgroup_set_classid(&sock->sk->sk_cgrp_data, ctx->classid);
     76	if (--ctx->batch == 0) {
     77		ctx->batch = UPDATE_CLASSID_BATCH;
     78		return n + 1;
     79	}
     80	return 0;
     81}
     82
     83static void update_classid_task(struct task_struct *p, u32 classid)
     84{
     85	struct update_classid_context ctx = {
     86		.classid = classid,
     87		.batch = UPDATE_CLASSID_BATCH
     88	};
     89	unsigned int fd = 0;
     90
     91	do {
     92		task_lock(p);
     93		fd = iterate_fd(p->files, fd, update_classid_sock, &ctx);
     94		task_unlock(p);
     95		cond_resched();
     96	} while (fd);
     97}
     98
     99static void cgrp_attach(struct cgroup_taskset *tset)
    100{
    101	struct cgroup_subsys_state *css;
    102	struct task_struct *p;
    103
    104	cgroup_taskset_for_each(p, css, tset) {
    105		update_classid_task(p, css_cls_state(css)->classid);
    106	}
    107}
    108
    109static u64 read_classid(struct cgroup_subsys_state *css, struct cftype *cft)
    110{
    111	return css_cls_state(css)->classid;
    112}
    113
    114static int write_classid(struct cgroup_subsys_state *css, struct cftype *cft,
    115			 u64 value)
    116{
    117	struct cgroup_cls_state *cs = css_cls_state(css);
    118	struct css_task_iter it;
    119	struct task_struct *p;
    120
    121	cs->classid = (u32)value;
    122
    123	css_task_iter_start(css, 0, &it);
    124	while ((p = css_task_iter_next(&it)))
    125		update_classid_task(p, cs->classid);
    126	css_task_iter_end(&it);
    127
    128	return 0;
    129}
    130
    131static struct cftype ss_files[] = {
    132	{
    133		.name		= "classid",
    134		.read_u64	= read_classid,
    135		.write_u64	= write_classid,
    136	},
    137	{ }	/* terminate */
    138};
    139
    140struct cgroup_subsys net_cls_cgrp_subsys = {
    141	.css_alloc		= cgrp_css_alloc,
    142	.css_online		= cgrp_css_online,
    143	.css_free		= cgrp_css_free,
    144	.attach			= cgrp_attach,
    145	.legacy_cftypes		= ss_files,
    146};