1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * cn_proc.c - process events connector
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.
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>
20 #include <linux/cn_proc.h>
21 #include <linux/local_lock.h>
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.
30 #define CN_PROC_MSG_SIZE (sizeof(struct cn_msg) + sizeof(struct proc_event) + 4)
32 /* See comment above; we test our assumption about sizeof struct cn_msg here. */
33 static inline struct cn_msg *buffer_to_cn_msg(__u8 *buffer)
35 BUILD_BUG_ON(sizeof(struct cn_msg) != 20);
36 return (struct cn_msg *)(buffer + 4);
39 static atomic_t proc_event_num_listeners = ATOMIC_INIT(0);
40 static struct cb_id cn_proc_event_id = { CN_IDX_PROC, CN_VAL_PROC };
42 /* local_event.count is used as the sequence number of the netlink message */
47 static DEFINE_PER_CPU(struct local_event, local_event) = {
48 .lock = INIT_LOCAL_LOCK(lock),
51 static int cn_filter(struct sock *dsk, struct sk_buff *skb, void *data)
53 __u32 what, exit_code, *ptr;
54 enum proc_cn_mcast_op mc_op;
57 if (!dsk || !dsk->sk_user_data || !data)
63 val = ((struct proc_input *)(dsk->sk_user_data))->event_type;
64 mc_op = ((struct proc_input *)(dsk->sk_user_data))->mcast_op;
66 if (mc_op == PROC_CN_MCAST_IGNORE)
69 if ((__u32)val == PROC_EVENT_ALL)
73 * Drop packet if we have to report only non-zero exit status
74 * (PROC_EVENT_NONZERO_EXIT) and exit status is 0
76 if (((__u32)val & PROC_EVENT_NONZERO_EXIT) &&
77 (what == PROC_EVENT_EXIT)) {
82 if ((__u32)val & what)
88 static inline void send_msg(struct cn_msg *msg)
92 local_lock(&local_event.lock);
94 msg->seq = __this_cpu_inc_return(local_event.count) - 1;
95 ((struct proc_event *)msg->data)->cpu = smp_processor_id();
98 * local_lock() disables preemption during send to ensure the messages
99 * are ordered according to their sequence numbers.
101 * If cn_netlink_send() fails, the data is not sent.
103 filter_data[0] = ((struct proc_event *)msg->data)->what;
104 if (filter_data[0] == PROC_EVENT_EXIT) {
106 ((struct proc_event *)msg->data)->event_data.exit.exit_code;
111 if (cn_netlink_send_mult(msg, msg->len, 0, CN_IDX_PROC, GFP_NOWAIT,
112 cn_filter, (void *)filter_data) == -ESRCH)
113 atomic_set(&proc_event_num_listeners, 0);
115 local_unlock(&local_event.lock);
118 void proc_fork_connector(struct task_struct *task)
121 struct proc_event *ev;
122 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
123 struct task_struct *parent;
125 if (atomic_read(&proc_event_num_listeners) < 1)
128 msg = buffer_to_cn_msg(buffer);
129 ev = (struct proc_event *)msg->data;
130 memset(&ev->event_data, 0, sizeof(ev->event_data));
131 ev->timestamp_ns = ktime_get_ns();
132 ev->what = PROC_EVENT_FORK;
134 parent = rcu_dereference(task->real_parent);
135 ev->event_data.fork.parent_pid = parent->pid;
136 ev->event_data.fork.parent_tgid = parent->tgid;
138 ev->event_data.fork.child_pid = task->pid;
139 ev->event_data.fork.child_tgid = task->tgid;
141 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
142 msg->ack = 0; /* not used */
143 msg->len = sizeof(*ev);
144 msg->flags = 0; /* not used */
148 void proc_exec_connector(struct task_struct *task)
151 struct proc_event *ev;
152 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
154 if (atomic_read(&proc_event_num_listeners) < 1)
157 msg = buffer_to_cn_msg(buffer);
158 ev = (struct proc_event *)msg->data;
159 memset(&ev->event_data, 0, sizeof(ev->event_data));
160 ev->timestamp_ns = ktime_get_ns();
161 ev->what = PROC_EVENT_EXEC;
162 ev->event_data.exec.process_pid = task->pid;
163 ev->event_data.exec.process_tgid = task->tgid;
165 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
166 msg->ack = 0; /* not used */
167 msg->len = sizeof(*ev);
168 msg->flags = 0; /* not used */
172 void proc_id_connector(struct task_struct *task, int which_id)
175 struct proc_event *ev;
176 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
177 const struct cred *cred;
179 if (atomic_read(&proc_event_num_listeners) < 1)
182 msg = buffer_to_cn_msg(buffer);
183 ev = (struct proc_event *)msg->data;
184 memset(&ev->event_data, 0, sizeof(ev->event_data));
186 ev->event_data.id.process_pid = task->pid;
187 ev->event_data.id.process_tgid = task->tgid;
189 cred = __task_cred(task);
190 if (which_id == PROC_EVENT_UID) {
191 ev->event_data.id.r.ruid = from_kuid_munged(&init_user_ns, cred->uid);
192 ev->event_data.id.e.euid = from_kuid_munged(&init_user_ns, cred->euid);
193 } else if (which_id == PROC_EVENT_GID) {
194 ev->event_data.id.r.rgid = from_kgid_munged(&init_user_ns, cred->gid);
195 ev->event_data.id.e.egid = from_kgid_munged(&init_user_ns, cred->egid);
201 ev->timestamp_ns = ktime_get_ns();
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 */
210 void proc_sid_connector(struct task_struct *task)
213 struct proc_event *ev;
214 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
216 if (atomic_read(&proc_event_num_listeners) < 1)
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_SID;
224 ev->event_data.sid.process_pid = task->pid;
225 ev->event_data.sid.process_tgid = task->tgid;
227 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
228 msg->ack = 0; /* not used */
229 msg->len = sizeof(*ev);
230 msg->flags = 0; /* not used */
234 void proc_ptrace_connector(struct task_struct *task, int ptrace_id)
237 struct proc_event *ev;
238 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
240 if (atomic_read(&proc_event_num_listeners) < 1)
243 msg = buffer_to_cn_msg(buffer);
244 ev = (struct proc_event *)msg->data;
245 memset(&ev->event_data, 0, sizeof(ev->event_data));
246 ev->timestamp_ns = ktime_get_ns();
247 ev->what = PROC_EVENT_PTRACE;
248 ev->event_data.ptrace.process_pid = task->pid;
249 ev->event_data.ptrace.process_tgid = task->tgid;
250 if (ptrace_id == PTRACE_ATTACH) {
251 ev->event_data.ptrace.tracer_pid = current->pid;
252 ev->event_data.ptrace.tracer_tgid = current->tgid;
253 } else if (ptrace_id == PTRACE_DETACH) {
254 ev->event_data.ptrace.tracer_pid = 0;
255 ev->event_data.ptrace.tracer_tgid = 0;
259 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
260 msg->ack = 0; /* not used */
261 msg->len = sizeof(*ev);
262 msg->flags = 0; /* not used */
266 void proc_comm_connector(struct task_struct *task)
269 struct proc_event *ev;
270 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
272 if (atomic_read(&proc_event_num_listeners) < 1)
275 msg = buffer_to_cn_msg(buffer);
276 ev = (struct proc_event *)msg->data;
277 memset(&ev->event_data, 0, sizeof(ev->event_data));
278 ev->timestamp_ns = ktime_get_ns();
279 ev->what = PROC_EVENT_COMM;
280 ev->event_data.comm.process_pid = task->pid;
281 ev->event_data.comm.process_tgid = task->tgid;
282 get_task_comm(ev->event_data.comm.comm, task);
284 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
285 msg->ack = 0; /* not used */
286 msg->len = sizeof(*ev);
287 msg->flags = 0; /* not used */
291 void proc_coredump_connector(struct task_struct *task)
294 struct proc_event *ev;
295 struct task_struct *parent;
296 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
298 if (atomic_read(&proc_event_num_listeners) < 1)
301 msg = buffer_to_cn_msg(buffer);
302 ev = (struct proc_event *)msg->data;
303 memset(&ev->event_data, 0, sizeof(ev->event_data));
304 ev->timestamp_ns = ktime_get_ns();
305 ev->what = PROC_EVENT_COREDUMP;
306 ev->event_data.coredump.process_pid = task->pid;
307 ev->event_data.coredump.process_tgid = task->tgid;
310 if (pid_alive(task)) {
311 parent = rcu_dereference(task->real_parent);
312 ev->event_data.coredump.parent_pid = parent->pid;
313 ev->event_data.coredump.parent_tgid = parent->tgid;
317 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
318 msg->ack = 0; /* not used */
319 msg->len = sizeof(*ev);
320 msg->flags = 0; /* not used */
324 void proc_exit_connector(struct task_struct *task)
327 struct proc_event *ev;
328 struct task_struct *parent;
329 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
331 if (atomic_read(&proc_event_num_listeners) < 1)
334 msg = buffer_to_cn_msg(buffer);
335 ev = (struct proc_event *)msg->data;
336 memset(&ev->event_data, 0, sizeof(ev->event_data));
337 ev->timestamp_ns = ktime_get_ns();
338 ev->what = PROC_EVENT_EXIT;
339 ev->event_data.exit.process_pid = task->pid;
340 ev->event_data.exit.process_tgid = task->tgid;
341 ev->event_data.exit.exit_code = task->exit_code;
342 ev->event_data.exit.exit_signal = task->exit_signal;
345 if (pid_alive(task)) {
346 parent = rcu_dereference(task->real_parent);
347 ev->event_data.exit.parent_pid = parent->pid;
348 ev->event_data.exit.parent_tgid = parent->tgid;
352 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
353 msg->ack = 0; /* not used */
354 msg->len = sizeof(*ev);
355 msg->flags = 0; /* not used */
360 * Send an acknowledgement message to userspace
362 * Use 0 for success, EFOO otherwise.
363 * Note: this is the negative of conventional kernel error
364 * values because it's not being returned via syscall return
367 static void cn_proc_ack(int err, int rcvd_seq, int rcvd_ack)
370 struct proc_event *ev;
371 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
373 if (atomic_read(&proc_event_num_listeners) < 1)
376 msg = buffer_to_cn_msg(buffer);
377 ev = (struct proc_event *)msg->data;
378 memset(&ev->event_data, 0, sizeof(ev->event_data));
380 ev->timestamp_ns = ktime_get_ns();
382 ev->what = PROC_EVENT_NONE;
383 ev->event_data.ack.err = err;
384 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
385 msg->ack = rcvd_ack + 1;
386 msg->len = sizeof(*ev);
387 msg->flags = 0; /* not used */
393 * @msg: message sent from userspace via the connector
394 * @nsp: NETLINK_CB of the client's socket buffer
396 static void cn_proc_mcast_ctl(struct cn_msg *msg,
397 struct netlink_skb_parms *nsp)
399 enum proc_cn_mcast_op mc_op = 0, prev_mc_op = 0;
400 struct proc_input *pinput = NULL;
401 enum proc_cn_event ev_type = 0;
402 int err = 0, initial = 0;
403 struct sock *sk = NULL;
406 * Events are reported with respect to the initial pid
407 * and user namespaces so ignore requestors from
410 if ((current_user_ns() != &init_user_ns) ||
411 !task_is_in_init_pid_ns(current))
414 if (msg->len == sizeof(*pinput)) {
415 pinput = (struct proc_input *)msg->data;
416 mc_op = pinput->mcast_op;
417 ev_type = pinput->event_type;
418 } else if (msg->len == sizeof(mc_op)) {
419 mc_op = *((enum proc_cn_mcast_op *)msg->data);
420 ev_type = PROC_EVENT_ALL;
425 ev_type = valid_event((enum proc_cn_event)ev_type);
427 if (ev_type == PROC_EVENT_NONE)
428 ev_type = PROC_EVENT_ALL;
432 if (sk->sk_user_data == NULL) {
433 sk->sk_user_data = kzalloc(sizeof(struct proc_input),
435 if (sk->sk_user_data == NULL) {
442 ((struct proc_input *)(sk->sk_user_data))->mcast_op;
444 ((struct proc_input *)(sk->sk_user_data))->event_type =
446 ((struct proc_input *)(sk->sk_user_data))->mcast_op = mc_op;
450 case PROC_CN_MCAST_LISTEN:
451 if (initial || (prev_mc_op != PROC_CN_MCAST_LISTEN))
452 atomic_inc(&proc_event_num_listeners);
454 case PROC_CN_MCAST_IGNORE:
455 if (!initial && (prev_mc_op != PROC_CN_MCAST_IGNORE))
456 atomic_dec(&proc_event_num_listeners);
457 ((struct proc_input *)(sk->sk_user_data))->event_type =
466 cn_proc_ack(err, msg->seq, msg->ack);
470 * cn_proc_init - initialization entry point
472 * Adds the connector callback to the connector driver.
474 static int __init cn_proc_init(void)
476 int err = cn_add_callback(&cn_proc_event_id,
480 pr_warn("cn_proc failed to register\n");
485 device_initcall(cn_proc_init);