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1/*
2 * cn_proc.c - process events connector
3 *
4 * Copyright (C) Matt Helsley, IBM Corp. 2005
5 * Based on cn_fork.c by Guillaume Thouvenin <guillaume.thouvenin@bull.net>
6 * Original copyright notice follows:
7 * Copyright (C) 2005 BULL SA.
8 *
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 */
24
25#include <linux/module.h>
26#include <linux/kernel.h>
27#include <linux/ktime.h>
28#include <linux/init.h>
29#include <linux/connector.h>
30#include <linux/gfp.h>
31#include <linux/ptrace.h>
32#include <linux/atomic.h>
33
34#include <asm/unaligned.h>
35
36#include <linux/cn_proc.h>
37
38#define CN_PROC_MSG_SIZE (sizeof(struct cn_msg) + sizeof(struct proc_event))
39
40static atomic_t proc_event_num_listeners = ATOMIC_INIT(0);
41static struct cb_id cn_proc_event_id = { CN_IDX_PROC, CN_VAL_PROC };
42
43/* proc_event_counts is used as the sequence number of the netlink message */
44static DEFINE_PER_CPU(__u32, proc_event_counts) = { 0 };
45
46static inline void get_seq(__u32 *ts, int *cpu)
47{
48 preempt_disable();
49 *ts = __this_cpu_inc_return(proc_event_counts) -1;
50 *cpu = smp_processor_id();
51 preempt_enable();
52}
53
54void proc_fork_connector(struct task_struct *task)
55{
56 struct cn_msg *msg;
57 struct proc_event *ev;
58 __u8 buffer[CN_PROC_MSG_SIZE];
59 struct timespec ts;
60 struct task_struct *parent;
61
62 if (atomic_read(&proc_event_num_listeners) < 1)
63 return;
64
65 msg = (struct cn_msg*)buffer;
66 ev = (struct proc_event*)msg->data;
67 get_seq(&msg->seq, &ev->cpu);
68 ktime_get_ts(&ts); /* get high res monotonic timestamp */
69 put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
70 ev->what = PROC_EVENT_FORK;
71 rcu_read_lock();
72 parent = rcu_dereference(task->real_parent);
73 ev->event_data.fork.parent_pid = parent->pid;
74 ev->event_data.fork.parent_tgid = parent->tgid;
75 rcu_read_unlock();
76 ev->event_data.fork.child_pid = task->pid;
77 ev->event_data.fork.child_tgid = task->tgid;
78
79 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
80 msg->ack = 0; /* not used */
81 msg->len = sizeof(*ev);
82 /* If cn_netlink_send() failed, the data is not sent */
83 cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
84}
85
86void proc_exec_connector(struct task_struct *task)
87{
88 struct cn_msg *msg;
89 struct proc_event *ev;
90 struct timespec ts;
91 __u8 buffer[CN_PROC_MSG_SIZE];
92
93 if (atomic_read(&proc_event_num_listeners) < 1)
94 return;
95
96 msg = (struct cn_msg*)buffer;
97 ev = (struct proc_event*)msg->data;
98 get_seq(&msg->seq, &ev->cpu);
99 ktime_get_ts(&ts); /* get high res monotonic timestamp */
100 put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
101 ev->what = PROC_EVENT_EXEC;
102 ev->event_data.exec.process_pid = task->pid;
103 ev->event_data.exec.process_tgid = task->tgid;
104
105 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
106 msg->ack = 0; /* not used */
107 msg->len = sizeof(*ev);
108 cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
109}
110
111void proc_id_connector(struct task_struct *task, int which_id)
112{
113 struct cn_msg *msg;
114 struct proc_event *ev;
115 __u8 buffer[CN_PROC_MSG_SIZE];
116 struct timespec ts;
117 const struct cred *cred;
118
119 if (atomic_read(&proc_event_num_listeners) < 1)
120 return;
121
122 msg = (struct cn_msg*)buffer;
123 ev = (struct proc_event*)msg->data;
124 ev->what = which_id;
125 ev->event_data.id.process_pid = task->pid;
126 ev->event_data.id.process_tgid = task->tgid;
127 rcu_read_lock();
128 cred = __task_cred(task);
129 if (which_id == PROC_EVENT_UID) {
130 ev->event_data.id.r.ruid = cred->uid;
131 ev->event_data.id.e.euid = cred->euid;
132 } else if (which_id == PROC_EVENT_GID) {
133 ev->event_data.id.r.rgid = cred->gid;
134 ev->event_data.id.e.egid = cred->egid;
135 } else {
136 rcu_read_unlock();
137 return;
138 }
139 rcu_read_unlock();
140 get_seq(&msg->seq, &ev->cpu);
141 ktime_get_ts(&ts); /* get high res monotonic timestamp */
142 put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
143
144 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
145 msg->ack = 0; /* not used */
146 msg->len = sizeof(*ev);
147 cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
148}
149
150void proc_sid_connector(struct task_struct *task)
151{
152 struct cn_msg *msg;
153 struct proc_event *ev;
154 struct timespec ts;
155 __u8 buffer[CN_PROC_MSG_SIZE];
156
157 if (atomic_read(&proc_event_num_listeners) < 1)
158 return;
159
160 msg = (struct cn_msg *)buffer;
161 ev = (struct proc_event *)msg->data;
162 get_seq(&msg->seq, &ev->cpu);
163 ktime_get_ts(&ts); /* get high res monotonic timestamp */
164 put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
165 ev->what = PROC_EVENT_SID;
166 ev->event_data.sid.process_pid = task->pid;
167 ev->event_data.sid.process_tgid = task->tgid;
168
169 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
170 msg->ack = 0; /* not used */
171 msg->len = sizeof(*ev);
172 cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
173}
174
175void proc_ptrace_connector(struct task_struct *task, int ptrace_id)
176{
177 struct cn_msg *msg;
178 struct proc_event *ev;
179 struct timespec ts;
180 __u8 buffer[CN_PROC_MSG_SIZE];
181
182 if (atomic_read(&proc_event_num_listeners) < 1)
183 return;
184
185 msg = (struct cn_msg *)buffer;
186 ev = (struct proc_event *)msg->data;
187 get_seq(&msg->seq, &ev->cpu);
188 ktime_get_ts(&ts); /* get high res monotonic timestamp */
189 put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
190 ev->what = PROC_EVENT_PTRACE;
191 ev->event_data.ptrace.process_pid = task->pid;
192 ev->event_data.ptrace.process_tgid = task->tgid;
193 if (ptrace_id == PTRACE_ATTACH) {
194 ev->event_data.ptrace.tracer_pid = current->pid;
195 ev->event_data.ptrace.tracer_tgid = current->tgid;
196 } else if (ptrace_id == PTRACE_DETACH) {
197 ev->event_data.ptrace.tracer_pid = 0;
198 ev->event_data.ptrace.tracer_tgid = 0;
199 } else
200 return;
201
202 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
203 msg->ack = 0; /* not used */
204 msg->len = sizeof(*ev);
205 cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
206}
207
208void proc_exit_connector(struct task_struct *task)
209{
210 struct cn_msg *msg;
211 struct proc_event *ev;
212 __u8 buffer[CN_PROC_MSG_SIZE];
213 struct timespec ts;
214
215 if (atomic_read(&proc_event_num_listeners) < 1)
216 return;
217
218 msg = (struct cn_msg*)buffer;
219 ev = (struct proc_event*)msg->data;
220 get_seq(&msg->seq, &ev->cpu);
221 ktime_get_ts(&ts); /* get high res monotonic timestamp */
222 put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
223 ev->what = PROC_EVENT_EXIT;
224 ev->event_data.exit.process_pid = task->pid;
225 ev->event_data.exit.process_tgid = task->tgid;
226 ev->event_data.exit.exit_code = task->exit_code;
227 ev->event_data.exit.exit_signal = task->exit_signal;
228
229 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
230 msg->ack = 0; /* not used */
231 msg->len = sizeof(*ev);
232 cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
233}
234
235/*
236 * Send an acknowledgement message to userspace
237 *
238 * Use 0 for success, EFOO otherwise.
239 * Note: this is the negative of conventional kernel error
240 * values because it's not being returned via syscall return
241 * mechanisms.
242 */
243static void cn_proc_ack(int err, int rcvd_seq, int rcvd_ack)
244{
245 struct cn_msg *msg;
246 struct proc_event *ev;
247 __u8 buffer[CN_PROC_MSG_SIZE];
248 struct timespec ts;
249
250 if (atomic_read(&proc_event_num_listeners) < 1)
251 return;
252
253 msg = (struct cn_msg*)buffer;
254 ev = (struct proc_event*)msg->data;
255 msg->seq = rcvd_seq;
256 ktime_get_ts(&ts); /* get high res monotonic timestamp */
257 put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
258 ev->cpu = -1;
259 ev->what = PROC_EVENT_NONE;
260 ev->event_data.ack.err = err;
261 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
262 msg->ack = rcvd_ack + 1;
263 msg->len = sizeof(*ev);
264 cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
265}
266
267/**
268 * cn_proc_mcast_ctl
269 * @data: message sent from userspace via the connector
270 */
271static void cn_proc_mcast_ctl(struct cn_msg *msg,
272 struct netlink_skb_parms *nsp)
273{
274 enum proc_cn_mcast_op *mc_op = NULL;
275 int err = 0;
276
277 if (msg->len != sizeof(*mc_op))
278 return;
279
280 mc_op = (enum proc_cn_mcast_op*)msg->data;
281 switch (*mc_op) {
282 case PROC_CN_MCAST_LISTEN:
283 atomic_inc(&proc_event_num_listeners);
284 break;
285 case PROC_CN_MCAST_IGNORE:
286 atomic_dec(&proc_event_num_listeners);
287 break;
288 default:
289 err = EINVAL;
290 break;
291 }
292 cn_proc_ack(err, msg->seq, msg->ack);
293}
294
295/*
296 * cn_proc_init - initialization entry point
297 *
298 * Adds the connector callback to the connector driver.
299 */
300static int __init cn_proc_init(void)
301{
302 int err;
303
304 if ((err = cn_add_callback(&cn_proc_event_id, "cn_proc",
305 &cn_proc_mcast_ctl))) {
306 printk(KERN_WARNING "cn_proc failed to register\n");
307 return err;
308 }
309 return 0;
310}
311
312module_init(cn_proc_init);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * cn_proc.c - process events connector
4 *
5 * Copyright (C) Matt Helsley, IBM Corp. 2005
6 * Based on cn_fork.c by Guillaume Thouvenin <guillaume.thouvenin@bull.net>
7 * Original copyright notice follows:
8 * Copyright (C) 2005 BULL SA.
9 */
10
11#include <linux/kernel.h>
12#include <linux/ktime.h>
13#include <linux/init.h>
14#include <linux/connector.h>
15#include <linux/gfp.h>
16#include <linux/ptrace.h>
17#include <linux/atomic.h>
18#include <linux/pid_namespace.h>
19
20#include <linux/cn_proc.h>
21
22/*
23 * Size of a cn_msg followed by a proc_event structure. Since the
24 * sizeof struct cn_msg is a multiple of 4 bytes, but not 8 bytes, we
25 * add one 4-byte word to the size here, and then start the actual
26 * cn_msg structure 4 bytes into the stack buffer. The result is that
27 * the immediately following proc_event structure is aligned to 8 bytes.
28 */
29#define CN_PROC_MSG_SIZE (sizeof(struct cn_msg) + sizeof(struct proc_event) + 4)
30
31/* See comment above; we test our assumption about sizeof struct cn_msg here. */
32static inline struct cn_msg *buffer_to_cn_msg(__u8 *buffer)
33{
34 BUILD_BUG_ON(sizeof(struct cn_msg) != 20);
35 return (struct cn_msg *)(buffer + 4);
36}
37
38static atomic_t proc_event_num_listeners = ATOMIC_INIT(0);
39static struct cb_id cn_proc_event_id = { CN_IDX_PROC, CN_VAL_PROC };
40
41/* proc_event_counts is used as the sequence number of the netlink message */
42static DEFINE_PER_CPU(__u32, proc_event_counts) = { 0 };
43
44static inline void send_msg(struct cn_msg *msg)
45{
46 preempt_disable();
47
48 msg->seq = __this_cpu_inc_return(proc_event_counts) - 1;
49 ((struct proc_event *)msg->data)->cpu = smp_processor_id();
50
51 /*
52 * Preemption remains disabled during send to ensure the messages are
53 * ordered according to their sequence numbers.
54 *
55 * If cn_netlink_send() fails, the data is not sent.
56 */
57 cn_netlink_send(msg, 0, CN_IDX_PROC, GFP_NOWAIT);
58
59 preempt_enable();
60}
61
62void proc_fork_connector(struct task_struct *task)
63{
64 struct cn_msg *msg;
65 struct proc_event *ev;
66 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
67 struct task_struct *parent;
68
69 if (atomic_read(&proc_event_num_listeners) < 1)
70 return;
71
72 msg = buffer_to_cn_msg(buffer);
73 ev = (struct proc_event *)msg->data;
74 memset(&ev->event_data, 0, sizeof(ev->event_data));
75 ev->timestamp_ns = ktime_get_ns();
76 ev->what = PROC_EVENT_FORK;
77 rcu_read_lock();
78 parent = rcu_dereference(task->real_parent);
79 ev->event_data.fork.parent_pid = parent->pid;
80 ev->event_data.fork.parent_tgid = parent->tgid;
81 rcu_read_unlock();
82 ev->event_data.fork.child_pid = task->pid;
83 ev->event_data.fork.child_tgid = task->tgid;
84
85 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
86 msg->ack = 0; /* not used */
87 msg->len = sizeof(*ev);
88 msg->flags = 0; /* not used */
89 send_msg(msg);
90}
91
92void proc_exec_connector(struct task_struct *task)
93{
94 struct cn_msg *msg;
95 struct proc_event *ev;
96 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
97
98 if (atomic_read(&proc_event_num_listeners) < 1)
99 return;
100
101 msg = buffer_to_cn_msg(buffer);
102 ev = (struct proc_event *)msg->data;
103 memset(&ev->event_data, 0, sizeof(ev->event_data));
104 ev->timestamp_ns = ktime_get_ns();
105 ev->what = PROC_EVENT_EXEC;
106 ev->event_data.exec.process_pid = task->pid;
107 ev->event_data.exec.process_tgid = task->tgid;
108
109 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
110 msg->ack = 0; /* not used */
111 msg->len = sizeof(*ev);
112 msg->flags = 0; /* not used */
113 send_msg(msg);
114}
115
116void proc_id_connector(struct task_struct *task, int which_id)
117{
118 struct cn_msg *msg;
119 struct proc_event *ev;
120 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
121 const struct cred *cred;
122
123 if (atomic_read(&proc_event_num_listeners) < 1)
124 return;
125
126 msg = buffer_to_cn_msg(buffer);
127 ev = (struct proc_event *)msg->data;
128 memset(&ev->event_data, 0, sizeof(ev->event_data));
129 ev->what = which_id;
130 ev->event_data.id.process_pid = task->pid;
131 ev->event_data.id.process_tgid = task->tgid;
132 rcu_read_lock();
133 cred = __task_cred(task);
134 if (which_id == PROC_EVENT_UID) {
135 ev->event_data.id.r.ruid = from_kuid_munged(&init_user_ns, cred->uid);
136 ev->event_data.id.e.euid = from_kuid_munged(&init_user_ns, cred->euid);
137 } else if (which_id == PROC_EVENT_GID) {
138 ev->event_data.id.r.rgid = from_kgid_munged(&init_user_ns, cred->gid);
139 ev->event_data.id.e.egid = from_kgid_munged(&init_user_ns, cred->egid);
140 } else {
141 rcu_read_unlock();
142 return;
143 }
144 rcu_read_unlock();
145 ev->timestamp_ns = ktime_get_ns();
146
147 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
148 msg->ack = 0; /* not used */
149 msg->len = sizeof(*ev);
150 msg->flags = 0; /* not used */
151 send_msg(msg);
152}
153
154void proc_sid_connector(struct task_struct *task)
155{
156 struct cn_msg *msg;
157 struct proc_event *ev;
158 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
159
160 if (atomic_read(&proc_event_num_listeners) < 1)
161 return;
162
163 msg = buffer_to_cn_msg(buffer);
164 ev = (struct proc_event *)msg->data;
165 memset(&ev->event_data, 0, sizeof(ev->event_data));
166 ev->timestamp_ns = ktime_get_ns();
167 ev->what = PROC_EVENT_SID;
168 ev->event_data.sid.process_pid = task->pid;
169 ev->event_data.sid.process_tgid = task->tgid;
170
171 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
172 msg->ack = 0; /* not used */
173 msg->len = sizeof(*ev);
174 msg->flags = 0; /* not used */
175 send_msg(msg);
176}
177
178void proc_ptrace_connector(struct task_struct *task, int ptrace_id)
179{
180 struct cn_msg *msg;
181 struct proc_event *ev;
182 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
183
184 if (atomic_read(&proc_event_num_listeners) < 1)
185 return;
186
187 msg = buffer_to_cn_msg(buffer);
188 ev = (struct proc_event *)msg->data;
189 memset(&ev->event_data, 0, sizeof(ev->event_data));
190 ev->timestamp_ns = ktime_get_ns();
191 ev->what = PROC_EVENT_PTRACE;
192 ev->event_data.ptrace.process_pid = task->pid;
193 ev->event_data.ptrace.process_tgid = task->tgid;
194 if (ptrace_id == PTRACE_ATTACH) {
195 ev->event_data.ptrace.tracer_pid = current->pid;
196 ev->event_data.ptrace.tracer_tgid = current->tgid;
197 } else if (ptrace_id == PTRACE_DETACH) {
198 ev->event_data.ptrace.tracer_pid = 0;
199 ev->event_data.ptrace.tracer_tgid = 0;
200 } else
201 return;
202
203 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
204 msg->ack = 0; /* not used */
205 msg->len = sizeof(*ev);
206 msg->flags = 0; /* not used */
207 send_msg(msg);
208}
209
210void proc_comm_connector(struct task_struct *task)
211{
212 struct cn_msg *msg;
213 struct proc_event *ev;
214 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
215
216 if (atomic_read(&proc_event_num_listeners) < 1)
217 return;
218
219 msg = buffer_to_cn_msg(buffer);
220 ev = (struct proc_event *)msg->data;
221 memset(&ev->event_data, 0, sizeof(ev->event_data));
222 ev->timestamp_ns = ktime_get_ns();
223 ev->what = PROC_EVENT_COMM;
224 ev->event_data.comm.process_pid = task->pid;
225 ev->event_data.comm.process_tgid = task->tgid;
226 get_task_comm(ev->event_data.comm.comm, task);
227
228 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
229 msg->ack = 0; /* not used */
230 msg->len = sizeof(*ev);
231 msg->flags = 0; /* not used */
232 send_msg(msg);
233}
234
235void proc_coredump_connector(struct task_struct *task)
236{
237 struct cn_msg *msg;
238 struct proc_event *ev;
239 struct task_struct *parent;
240 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
241
242 if (atomic_read(&proc_event_num_listeners) < 1)
243 return;
244
245 msg = buffer_to_cn_msg(buffer);
246 ev = (struct proc_event *)msg->data;
247 memset(&ev->event_data, 0, sizeof(ev->event_data));
248 ev->timestamp_ns = ktime_get_ns();
249 ev->what = PROC_EVENT_COREDUMP;
250 ev->event_data.coredump.process_pid = task->pid;
251 ev->event_data.coredump.process_tgid = task->tgid;
252
253 rcu_read_lock();
254 if (pid_alive(task)) {
255 parent = rcu_dereference(task->real_parent);
256 ev->event_data.coredump.parent_pid = parent->pid;
257 ev->event_data.coredump.parent_tgid = parent->tgid;
258 }
259 rcu_read_unlock();
260
261 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
262 msg->ack = 0; /* not used */
263 msg->len = sizeof(*ev);
264 msg->flags = 0; /* not used */
265 send_msg(msg);
266}
267
268void proc_exit_connector(struct task_struct *task)
269{
270 struct cn_msg *msg;
271 struct proc_event *ev;
272 struct task_struct *parent;
273 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
274
275 if (atomic_read(&proc_event_num_listeners) < 1)
276 return;
277
278 msg = buffer_to_cn_msg(buffer);
279 ev = (struct proc_event *)msg->data;
280 memset(&ev->event_data, 0, sizeof(ev->event_data));
281 ev->timestamp_ns = ktime_get_ns();
282 ev->what = PROC_EVENT_EXIT;
283 ev->event_data.exit.process_pid = task->pid;
284 ev->event_data.exit.process_tgid = task->tgid;
285 ev->event_data.exit.exit_code = task->exit_code;
286 ev->event_data.exit.exit_signal = task->exit_signal;
287
288 rcu_read_lock();
289 if (pid_alive(task)) {
290 parent = rcu_dereference(task->real_parent);
291 ev->event_data.exit.parent_pid = parent->pid;
292 ev->event_data.exit.parent_tgid = parent->tgid;
293 }
294 rcu_read_unlock();
295
296 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
297 msg->ack = 0; /* not used */
298 msg->len = sizeof(*ev);
299 msg->flags = 0; /* not used */
300 send_msg(msg);
301}
302
303/*
304 * Send an acknowledgement message to userspace
305 *
306 * Use 0 for success, EFOO otherwise.
307 * Note: this is the negative of conventional kernel error
308 * values because it's not being returned via syscall return
309 * mechanisms.
310 */
311static void cn_proc_ack(int err, int rcvd_seq, int rcvd_ack)
312{
313 struct cn_msg *msg;
314 struct proc_event *ev;
315 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
316
317 if (atomic_read(&proc_event_num_listeners) < 1)
318 return;
319
320 msg = buffer_to_cn_msg(buffer);
321 ev = (struct proc_event *)msg->data;
322 memset(&ev->event_data, 0, sizeof(ev->event_data));
323 msg->seq = rcvd_seq;
324 ev->timestamp_ns = ktime_get_ns();
325 ev->cpu = -1;
326 ev->what = PROC_EVENT_NONE;
327 ev->event_data.ack.err = err;
328 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
329 msg->ack = rcvd_ack + 1;
330 msg->len = sizeof(*ev);
331 msg->flags = 0; /* not used */
332 send_msg(msg);
333}
334
335/**
336 * cn_proc_mcast_ctl
337 * @data: message sent from userspace via the connector
338 */
339static void cn_proc_mcast_ctl(struct cn_msg *msg,
340 struct netlink_skb_parms *nsp)
341{
342 enum proc_cn_mcast_op *mc_op = NULL;
343 int err = 0;
344
345 if (msg->len != sizeof(*mc_op))
346 return;
347
348 /*
349 * Events are reported with respect to the initial pid
350 * and user namespaces so ignore requestors from
351 * other namespaces.
352 */
353 if ((current_user_ns() != &init_user_ns) ||
354 (task_active_pid_ns(current) != &init_pid_ns))
355 return;
356
357 /* Can only change if privileged. */
358 if (!__netlink_ns_capable(nsp, &init_user_ns, CAP_NET_ADMIN)) {
359 err = EPERM;
360 goto out;
361 }
362
363 mc_op = (enum proc_cn_mcast_op *)msg->data;
364 switch (*mc_op) {
365 case PROC_CN_MCAST_LISTEN:
366 atomic_inc(&proc_event_num_listeners);
367 break;
368 case PROC_CN_MCAST_IGNORE:
369 atomic_dec(&proc_event_num_listeners);
370 break;
371 default:
372 err = EINVAL;
373 break;
374 }
375
376out:
377 cn_proc_ack(err, msg->seq, msg->ack);
378}
379
380/*
381 * cn_proc_init - initialization entry point
382 *
383 * Adds the connector callback to the connector driver.
384 */
385static int __init cn_proc_init(void)
386{
387 int err = cn_add_callback(&cn_proc_event_id,
388 "cn_proc",
389 &cn_proc_mcast_ctl);
390 if (err) {
391 pr_warn("cn_proc failed to register\n");
392 return err;
393 }
394 return 0;
395}
396device_initcall(cn_proc_init);