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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#include <linux/local_lock.h>
22
23/*
24 * Size of a cn_msg followed by a proc_event structure. Since the
25 * sizeof struct cn_msg is a multiple of 4 bytes, but not 8 bytes, we
26 * add one 4-byte word to the size here, and then start the actual
27 * cn_msg structure 4 bytes into the stack buffer. The result is that
28 * the immediately following proc_event structure is aligned to 8 bytes.
29 */
30#define CN_PROC_MSG_SIZE (sizeof(struct cn_msg) + sizeof(struct proc_event) + 4)
31
32/* See comment above; we test our assumption about sizeof struct cn_msg here. */
33static inline struct cn_msg *buffer_to_cn_msg(__u8 *buffer)
34{
35 BUILD_BUG_ON(sizeof(struct cn_msg) != 20);
36 return (struct cn_msg *)(buffer + 4);
37}
38
39static atomic_t proc_event_num_listeners = ATOMIC_INIT(0);
40static struct cb_id cn_proc_event_id = { CN_IDX_PROC, CN_VAL_PROC };
41
42/* local_event.count is used as the sequence number of the netlink message */
43struct local_event {
44 local_lock_t lock;
45 __u32 count;
46};
47static DEFINE_PER_CPU(struct local_event, local_event) = {
48 .lock = INIT_LOCAL_LOCK(lock),
49};
50
51static inline void send_msg(struct cn_msg *msg)
52{
53 local_lock(&local_event.lock);
54
55 msg->seq = __this_cpu_inc_return(local_event.count) - 1;
56 ((struct proc_event *)msg->data)->cpu = smp_processor_id();
57
58 /*
59 * local_lock() disables preemption during send to ensure the messages
60 * are ordered according to their sequence numbers.
61 *
62 * If cn_netlink_send() fails, the data is not sent.
63 */
64 cn_netlink_send(msg, 0, CN_IDX_PROC, GFP_NOWAIT);
65
66 local_unlock(&local_event.lock);
67}
68
69void proc_fork_connector(struct task_struct *task)
70{
71 struct cn_msg *msg;
72 struct proc_event *ev;
73 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
74 struct task_struct *parent;
75
76 if (atomic_read(&proc_event_num_listeners) < 1)
77 return;
78
79 msg = buffer_to_cn_msg(buffer);
80 ev = (struct proc_event *)msg->data;
81 memset(&ev->event_data, 0, sizeof(ev->event_data));
82 ev->timestamp_ns = ktime_get_ns();
83 ev->what = PROC_EVENT_FORK;
84 rcu_read_lock();
85 parent = rcu_dereference(task->real_parent);
86 ev->event_data.fork.parent_pid = parent->pid;
87 ev->event_data.fork.parent_tgid = parent->tgid;
88 rcu_read_unlock();
89 ev->event_data.fork.child_pid = task->pid;
90 ev->event_data.fork.child_tgid = task->tgid;
91
92 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
93 msg->ack = 0; /* not used */
94 msg->len = sizeof(*ev);
95 msg->flags = 0; /* not used */
96 send_msg(msg);
97}
98
99void proc_exec_connector(struct task_struct *task)
100{
101 struct cn_msg *msg;
102 struct proc_event *ev;
103 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
104
105 if (atomic_read(&proc_event_num_listeners) < 1)
106 return;
107
108 msg = buffer_to_cn_msg(buffer);
109 ev = (struct proc_event *)msg->data;
110 memset(&ev->event_data, 0, sizeof(ev->event_data));
111 ev->timestamp_ns = ktime_get_ns();
112 ev->what = PROC_EVENT_EXEC;
113 ev->event_data.exec.process_pid = task->pid;
114 ev->event_data.exec.process_tgid = task->tgid;
115
116 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
117 msg->ack = 0; /* not used */
118 msg->len = sizeof(*ev);
119 msg->flags = 0; /* not used */
120 send_msg(msg);
121}
122
123void proc_id_connector(struct task_struct *task, int which_id)
124{
125 struct cn_msg *msg;
126 struct proc_event *ev;
127 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
128 const struct cred *cred;
129
130 if (atomic_read(&proc_event_num_listeners) < 1)
131 return;
132
133 msg = buffer_to_cn_msg(buffer);
134 ev = (struct proc_event *)msg->data;
135 memset(&ev->event_data, 0, sizeof(ev->event_data));
136 ev->what = which_id;
137 ev->event_data.id.process_pid = task->pid;
138 ev->event_data.id.process_tgid = task->tgid;
139 rcu_read_lock();
140 cred = __task_cred(task);
141 if (which_id == PROC_EVENT_UID) {
142 ev->event_data.id.r.ruid = from_kuid_munged(&init_user_ns, cred->uid);
143 ev->event_data.id.e.euid = from_kuid_munged(&init_user_ns, cred->euid);
144 } else if (which_id == PROC_EVENT_GID) {
145 ev->event_data.id.r.rgid = from_kgid_munged(&init_user_ns, cred->gid);
146 ev->event_data.id.e.egid = from_kgid_munged(&init_user_ns, cred->egid);
147 } else {
148 rcu_read_unlock();
149 return;
150 }
151 rcu_read_unlock();
152 ev->timestamp_ns = ktime_get_ns();
153
154 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
155 msg->ack = 0; /* not used */
156 msg->len = sizeof(*ev);
157 msg->flags = 0; /* not used */
158 send_msg(msg);
159}
160
161void proc_sid_connector(struct task_struct *task)
162{
163 struct cn_msg *msg;
164 struct proc_event *ev;
165 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
166
167 if (atomic_read(&proc_event_num_listeners) < 1)
168 return;
169
170 msg = buffer_to_cn_msg(buffer);
171 ev = (struct proc_event *)msg->data;
172 memset(&ev->event_data, 0, sizeof(ev->event_data));
173 ev->timestamp_ns = ktime_get_ns();
174 ev->what = PROC_EVENT_SID;
175 ev->event_data.sid.process_pid = task->pid;
176 ev->event_data.sid.process_tgid = task->tgid;
177
178 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
179 msg->ack = 0; /* not used */
180 msg->len = sizeof(*ev);
181 msg->flags = 0; /* not used */
182 send_msg(msg);
183}
184
185void proc_ptrace_connector(struct task_struct *task, int ptrace_id)
186{
187 struct cn_msg *msg;
188 struct proc_event *ev;
189 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
190
191 if (atomic_read(&proc_event_num_listeners) < 1)
192 return;
193
194 msg = buffer_to_cn_msg(buffer);
195 ev = (struct proc_event *)msg->data;
196 memset(&ev->event_data, 0, sizeof(ev->event_data));
197 ev->timestamp_ns = ktime_get_ns();
198 ev->what = PROC_EVENT_PTRACE;
199 ev->event_data.ptrace.process_pid = task->pid;
200 ev->event_data.ptrace.process_tgid = task->tgid;
201 if (ptrace_id == PTRACE_ATTACH) {
202 ev->event_data.ptrace.tracer_pid = current->pid;
203 ev->event_data.ptrace.tracer_tgid = current->tgid;
204 } else if (ptrace_id == PTRACE_DETACH) {
205 ev->event_data.ptrace.tracer_pid = 0;
206 ev->event_data.ptrace.tracer_tgid = 0;
207 } else
208 return;
209
210 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
211 msg->ack = 0; /* not used */
212 msg->len = sizeof(*ev);
213 msg->flags = 0; /* not used */
214 send_msg(msg);
215}
216
217void proc_comm_connector(struct task_struct *task)
218{
219 struct cn_msg *msg;
220 struct proc_event *ev;
221 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
222
223 if (atomic_read(&proc_event_num_listeners) < 1)
224 return;
225
226 msg = buffer_to_cn_msg(buffer);
227 ev = (struct proc_event *)msg->data;
228 memset(&ev->event_data, 0, sizeof(ev->event_data));
229 ev->timestamp_ns = ktime_get_ns();
230 ev->what = PROC_EVENT_COMM;
231 ev->event_data.comm.process_pid = task->pid;
232 ev->event_data.comm.process_tgid = task->tgid;
233 get_task_comm(ev->event_data.comm.comm, task);
234
235 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
236 msg->ack = 0; /* not used */
237 msg->len = sizeof(*ev);
238 msg->flags = 0; /* not used */
239 send_msg(msg);
240}
241
242void proc_coredump_connector(struct task_struct *task)
243{
244 struct cn_msg *msg;
245 struct proc_event *ev;
246 struct task_struct *parent;
247 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
248
249 if (atomic_read(&proc_event_num_listeners) < 1)
250 return;
251
252 msg = buffer_to_cn_msg(buffer);
253 ev = (struct proc_event *)msg->data;
254 memset(&ev->event_data, 0, sizeof(ev->event_data));
255 ev->timestamp_ns = ktime_get_ns();
256 ev->what = PROC_EVENT_COREDUMP;
257 ev->event_data.coredump.process_pid = task->pid;
258 ev->event_data.coredump.process_tgid = task->tgid;
259
260 rcu_read_lock();
261 if (pid_alive(task)) {
262 parent = rcu_dereference(task->real_parent);
263 ev->event_data.coredump.parent_pid = parent->pid;
264 ev->event_data.coredump.parent_tgid = parent->tgid;
265 }
266 rcu_read_unlock();
267
268 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
269 msg->ack = 0; /* not used */
270 msg->len = sizeof(*ev);
271 msg->flags = 0; /* not used */
272 send_msg(msg);
273}
274
275void proc_exit_connector(struct task_struct *task)
276{
277 struct cn_msg *msg;
278 struct proc_event *ev;
279 struct task_struct *parent;
280 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
281
282 if (atomic_read(&proc_event_num_listeners) < 1)
283 return;
284
285 msg = buffer_to_cn_msg(buffer);
286 ev = (struct proc_event *)msg->data;
287 memset(&ev->event_data, 0, sizeof(ev->event_data));
288 ev->timestamp_ns = ktime_get_ns();
289 ev->what = PROC_EVENT_EXIT;
290 ev->event_data.exit.process_pid = task->pid;
291 ev->event_data.exit.process_tgid = task->tgid;
292 ev->event_data.exit.exit_code = task->exit_code;
293 ev->event_data.exit.exit_signal = task->exit_signal;
294
295 rcu_read_lock();
296 if (pid_alive(task)) {
297 parent = rcu_dereference(task->real_parent);
298 ev->event_data.exit.parent_pid = parent->pid;
299 ev->event_data.exit.parent_tgid = parent->tgid;
300 }
301 rcu_read_unlock();
302
303 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
304 msg->ack = 0; /* not used */
305 msg->len = sizeof(*ev);
306 msg->flags = 0; /* not used */
307 send_msg(msg);
308}
309
310/*
311 * Send an acknowledgement message to userspace
312 *
313 * Use 0 for success, EFOO otherwise.
314 * Note: this is the negative of conventional kernel error
315 * values because it's not being returned via syscall return
316 * mechanisms.
317 */
318static void cn_proc_ack(int err, int rcvd_seq, int rcvd_ack)
319{
320 struct cn_msg *msg;
321 struct proc_event *ev;
322 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
323
324 if (atomic_read(&proc_event_num_listeners) < 1)
325 return;
326
327 msg = buffer_to_cn_msg(buffer);
328 ev = (struct proc_event *)msg->data;
329 memset(&ev->event_data, 0, sizeof(ev->event_data));
330 msg->seq = rcvd_seq;
331 ev->timestamp_ns = ktime_get_ns();
332 ev->cpu = -1;
333 ev->what = PROC_EVENT_NONE;
334 ev->event_data.ack.err = err;
335 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
336 msg->ack = rcvd_ack + 1;
337 msg->len = sizeof(*ev);
338 msg->flags = 0; /* not used */
339 send_msg(msg);
340}
341
342/**
343 * cn_proc_mcast_ctl
344 * @data: message sent from userspace via the connector
345 */
346static void cn_proc_mcast_ctl(struct cn_msg *msg,
347 struct netlink_skb_parms *nsp)
348{
349 enum proc_cn_mcast_op *mc_op = NULL;
350 int err = 0;
351
352 if (msg->len != sizeof(*mc_op))
353 return;
354
355 /*
356 * Events are reported with respect to the initial pid
357 * and user namespaces so ignore requestors from
358 * other namespaces.
359 */
360 if ((current_user_ns() != &init_user_ns) ||
361 !task_is_in_init_pid_ns(current))
362 return;
363
364 /* Can only change if privileged. */
365 if (!__netlink_ns_capable(nsp, &init_user_ns, CAP_NET_ADMIN)) {
366 err = EPERM;
367 goto out;
368 }
369
370 mc_op = (enum proc_cn_mcast_op *)msg->data;
371 switch (*mc_op) {
372 case PROC_CN_MCAST_LISTEN:
373 atomic_inc(&proc_event_num_listeners);
374 break;
375 case PROC_CN_MCAST_IGNORE:
376 atomic_dec(&proc_event_num_listeners);
377 break;
378 default:
379 err = EINVAL;
380 break;
381 }
382
383out:
384 cn_proc_ack(err, msg->seq, msg->ack);
385}
386
387/*
388 * cn_proc_init - initialization entry point
389 *
390 * Adds the connector callback to the connector driver.
391 */
392static int __init cn_proc_init(void)
393{
394 int err = cn_add_callback(&cn_proc_event_id,
395 "cn_proc",
396 &cn_proc_mcast_ctl);
397 if (err) {
398 pr_warn("cn_proc failed to register\n");
399 return err;
400 }
401 return 0;
402}
403device_initcall(cn_proc_init);