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1a59d1b8 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
9f46080c MH |
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. | |
9f46080c MH |
9 | */ |
10 | ||
9f46080c | 11 | #include <linux/kernel.h> |
caf3c9dc | 12 | #include <linux/ktime.h> |
9f46080c | 13 | #include <linux/init.h> |
1d31a4ea | 14 | #include <linux/connector.h> |
5a0e3ad6 | 15 | #include <linux/gfp.h> |
f701e5b7 | 16 | #include <linux/ptrace.h> |
60063497 | 17 | #include <linux/atomic.h> |
9582d901 | 18 | #include <linux/pid_namespace.h> |
60063497 | 19 | |
9f46080c | 20 | #include <linux/cn_proc.h> |
3e92fd7b | 21 | #include <linux/local_lock.h> |
9f46080c | 22 | |
1ca1a4cf CM |
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. */ | |
33 | static 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 | } | |
9f46080c MH |
38 | |
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 }; | |
41 | ||
3e92fd7b MG |
42 | /* local_event.count is used as the sequence number of the netlink message */ |
43 | struct local_event { | |
44 | local_lock_t lock; | |
45 | __u32 count; | |
46 | }; | |
47 | static DEFINE_PER_CPU(struct local_event, local_event) = { | |
48 | .lock = INIT_LOCAL_LOCK(lock), | |
49 | }; | |
9f46080c | 50 | |
ab8ed951 | 51 | static inline void send_msg(struct cn_msg *msg) |
9f46080c | 52 | { |
3e92fd7b | 53 | local_lock(&local_event.lock); |
ab8ed951 | 54 | |
3e92fd7b | 55 | msg->seq = __this_cpu_inc_return(local_event.count) - 1; |
ab8ed951 AC |
56 | ((struct proc_event *)msg->data)->cpu = smp_processor_id(); |
57 | ||
58 | /* | |
3e92fd7b MG |
59 | * local_lock() disables preemption during send to ensure the messages |
60 | * are ordered according to their sequence numbers. | |
ab8ed951 AC |
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 | ||
3e92fd7b | 66 | local_unlock(&local_event.lock); |
9f46080c MH |
67 | } |
68 | ||
69 | void proc_fork_connector(struct task_struct *task) | |
70 | { | |
71 | struct cn_msg *msg; | |
72 | struct proc_event *ev; | |
1ca1a4cf | 73 | __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); |
9e8f90df | 74 | struct task_struct *parent; |
9f46080c MH |
75 | |
76 | if (atomic_read(&proc_event_num_listeners) < 1) | |
77 | return; | |
78 | ||
1ca1a4cf | 79 | msg = buffer_to_cn_msg(buffer); |
f3c48ecc | 80 | ev = (struct proc_event *)msg->data; |
e727ca82 | 81 | memset(&ev->event_data, 0, sizeof(ev->event_data)); |
9e93f21b | 82 | ev->timestamp_ns = ktime_get_ns(); |
9f46080c | 83 | ev->what = PROC_EVENT_FORK; |
9e8f90df ON |
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(); | |
9f46080c MH |
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); | |
e727ca82 | 95 | msg->flags = 0; /* not used */ |
ab8ed951 | 96 | send_msg(msg); |
9f46080c MH |
97 | } |
98 | ||
99 | void proc_exec_connector(struct task_struct *task) | |
100 | { | |
101 | struct cn_msg *msg; | |
102 | struct proc_event *ev; | |
1ca1a4cf | 103 | __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); |
9f46080c MH |
104 | |
105 | if (atomic_read(&proc_event_num_listeners) < 1) | |
106 | return; | |
107 | ||
1ca1a4cf | 108 | msg = buffer_to_cn_msg(buffer); |
f3c48ecc | 109 | ev = (struct proc_event *)msg->data; |
e727ca82 | 110 | memset(&ev->event_data, 0, sizeof(ev->event_data)); |
9e93f21b | 111 | ev->timestamp_ns = ktime_get_ns(); |
9f46080c MH |
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); | |
e727ca82 | 119 | msg->flags = 0; /* not used */ |
ab8ed951 | 120 | send_msg(msg); |
9f46080c MH |
121 | } |
122 | ||
123 | void proc_id_connector(struct task_struct *task, int which_id) | |
124 | { | |
125 | struct cn_msg *msg; | |
126 | struct proc_event *ev; | |
1ca1a4cf | 127 | __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); |
c69e8d9c | 128 | const struct cred *cred; |
9f46080c MH |
129 | |
130 | if (atomic_read(&proc_event_num_listeners) < 1) | |
131 | return; | |
132 | ||
1ca1a4cf | 133 | msg = buffer_to_cn_msg(buffer); |
f3c48ecc | 134 | ev = (struct proc_event *)msg->data; |
e727ca82 | 135 | memset(&ev->event_data, 0, sizeof(ev->event_data)); |
9f46080c MH |
136 | ev->what = which_id; |
137 | ev->event_data.id.process_pid = task->pid; | |
138 | ev->event_data.id.process_tgid = task->tgid; | |
c69e8d9c DH |
139 | rcu_read_lock(); |
140 | cred = __task_cred(task); | |
9f46080c | 141 | if (which_id == PROC_EVENT_UID) { |
9582d901 EB |
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); | |
9f46080c | 144 | } else if (which_id == PROC_EVENT_GID) { |
9582d901 EB |
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); | |
c69e8d9c DH |
147 | } else { |
148 | rcu_read_unlock(); | |
f3c48ecc | 149 | return; |
c69e8d9c DH |
150 | } |
151 | rcu_read_unlock(); | |
9e93f21b | 152 | ev->timestamp_ns = ktime_get_ns(); |
9f46080c MH |
153 | |
154 | memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id)); | |
155 | msg->ack = 0; /* not used */ | |
156 | msg->len = sizeof(*ev); | |
e727ca82 | 157 | msg->flags = 0; /* not used */ |
ab8ed951 | 158 | send_msg(msg); |
9f46080c MH |
159 | } |
160 | ||
02b51df1 SJR |
161 | void proc_sid_connector(struct task_struct *task) |
162 | { | |
163 | struct cn_msg *msg; | |
164 | struct proc_event *ev; | |
1ca1a4cf | 165 | __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); |
02b51df1 SJR |
166 | |
167 | if (atomic_read(&proc_event_num_listeners) < 1) | |
168 | return; | |
169 | ||
1ca1a4cf | 170 | msg = buffer_to_cn_msg(buffer); |
02b51df1 | 171 | ev = (struct proc_event *)msg->data; |
e727ca82 | 172 | memset(&ev->event_data, 0, sizeof(ev->event_data)); |
9e93f21b | 173 | ev->timestamp_ns = ktime_get_ns(); |
02b51df1 SJR |
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); | |
e727ca82 | 181 | msg->flags = 0; /* not used */ |
ab8ed951 | 182 | send_msg(msg); |
02b51df1 SJR |
183 | } |
184 | ||
f701e5b7 VZ |
185 | void proc_ptrace_connector(struct task_struct *task, int ptrace_id) |
186 | { | |
187 | struct cn_msg *msg; | |
188 | struct proc_event *ev; | |
1ca1a4cf | 189 | __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); |
f701e5b7 VZ |
190 | |
191 | if (atomic_read(&proc_event_num_listeners) < 1) | |
192 | return; | |
193 | ||
1ca1a4cf | 194 | msg = buffer_to_cn_msg(buffer); |
f701e5b7 | 195 | ev = (struct proc_event *)msg->data; |
e727ca82 | 196 | memset(&ev->event_data, 0, sizeof(ev->event_data)); |
9e93f21b | 197 | ev->timestamp_ns = ktime_get_ns(); |
f701e5b7 VZ |
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); | |
e727ca82 | 213 | msg->flags = 0; /* not used */ |
ab8ed951 | 214 | send_msg(msg); |
f701e5b7 VZ |
215 | } |
216 | ||
f786ecba VZ |
217 | void proc_comm_connector(struct task_struct *task) |
218 | { | |
219 | struct cn_msg *msg; | |
220 | struct proc_event *ev; | |
1ca1a4cf | 221 | __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); |
f786ecba VZ |
222 | |
223 | if (atomic_read(&proc_event_num_listeners) < 1) | |
224 | return; | |
225 | ||
1ca1a4cf | 226 | msg = buffer_to_cn_msg(buffer); |
f786ecba | 227 | ev = (struct proc_event *)msg->data; |
e727ca82 | 228 | memset(&ev->event_data, 0, sizeof(ev->event_data)); |
9e93f21b | 229 | ev->timestamp_ns = ktime_get_ns(); |
f786ecba VZ |
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); | |
e727ca82 | 238 | msg->flags = 0; /* not used */ |
ab8ed951 | 239 | send_msg(msg); |
2b5faa4c JD |
240 | } |
241 | ||
242 | void proc_coredump_connector(struct task_struct *task) | |
243 | { | |
244 | struct cn_msg *msg; | |
245 | struct proc_event *ev; | |
6d2b0f02 | 246 | struct task_struct *parent; |
1ca1a4cf | 247 | __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); |
2b5faa4c JD |
248 | |
249 | if (atomic_read(&proc_event_num_listeners) < 1) | |
250 | return; | |
251 | ||
1ca1a4cf | 252 | msg = buffer_to_cn_msg(buffer); |
2b5faa4c | 253 | ev = (struct proc_event *)msg->data; |
e727ca82 | 254 | memset(&ev->event_data, 0, sizeof(ev->event_data)); |
9e93f21b | 255 | ev->timestamp_ns = ktime_get_ns(); |
2b5faa4c JD |
256 | ev->what = PROC_EVENT_COREDUMP; |
257 | ev->event_data.coredump.process_pid = task->pid; | |
258 | ev->event_data.coredump.process_tgid = task->tgid; | |
6d2b0f02 LR |
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(); | |
2b5faa4c JD |
267 | |
268 | memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id)); | |
269 | msg->ack = 0; /* not used */ | |
270 | msg->len = sizeof(*ev); | |
e727ca82 | 271 | msg->flags = 0; /* not used */ |
ab8ed951 | 272 | send_msg(msg); |
f786ecba VZ |
273 | } |
274 | ||
9f46080c MH |
275 | void proc_exit_connector(struct task_struct *task) |
276 | { | |
277 | struct cn_msg *msg; | |
278 | struct proc_event *ev; | |
6d2b0f02 | 279 | struct task_struct *parent; |
1ca1a4cf | 280 | __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); |
9f46080c MH |
281 | |
282 | if (atomic_read(&proc_event_num_listeners) < 1) | |
283 | return; | |
284 | ||
1ca1a4cf | 285 | msg = buffer_to_cn_msg(buffer); |
f3c48ecc | 286 | ev = (struct proc_event *)msg->data; |
e727ca82 | 287 | memset(&ev->event_data, 0, sizeof(ev->event_data)); |
9e93f21b | 288 | ev->timestamp_ns = ktime_get_ns(); |
9f46080c MH |
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; | |
6d2b0f02 LR |
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(); | |
9f46080c MH |
302 | |
303 | memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id)); | |
304 | msg->ack = 0; /* not used */ | |
305 | msg->len = sizeof(*ev); | |
e727ca82 | 306 | msg->flags = 0; /* not used */ |
ab8ed951 | 307 | send_msg(msg); |
9f46080c MH |
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 | */ | |
318 | static void cn_proc_ack(int err, int rcvd_seq, int rcvd_ack) | |
319 | { | |
320 | struct cn_msg *msg; | |
321 | struct proc_event *ev; | |
1ca1a4cf | 322 | __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); |
9f46080c MH |
323 | |
324 | if (atomic_read(&proc_event_num_listeners) < 1) | |
325 | return; | |
326 | ||
1ca1a4cf | 327 | msg = buffer_to_cn_msg(buffer); |
f3c48ecc | 328 | ev = (struct proc_event *)msg->data; |
e727ca82 | 329 | memset(&ev->event_data, 0, sizeof(ev->event_data)); |
9f46080c | 330 | msg->seq = rcvd_seq; |
9e93f21b | 331 | ev->timestamp_ns = ktime_get_ns(); |
9f46080c MH |
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); | |
e727ca82 | 338 | msg->flags = 0; /* not used */ |
ab8ed951 | 339 | send_msg(msg); |
9f46080c MH |
340 | } |
341 | ||
342 | /** | |
343 | * cn_proc_mcast_ctl | |
344 | * @data: message sent from userspace via the connector | |
345 | */ | |
f0b25932 SB |
346 | static void cn_proc_mcast_ctl(struct cn_msg *msg, |
347 | struct netlink_skb_parms *nsp) | |
9f46080c | 348 | { |
9f46080c MH |
349 | enum proc_cn_mcast_op *mc_op = NULL; |
350 | int err = 0; | |
351 | ||
352 | if (msg->len != sizeof(*mc_op)) | |
353 | return; | |
354 | ||
9582d901 EB |
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_active_pid_ns(current) != &init_pid_ns)) | |
362 | return; | |
363 | ||
e70ab977 | 364 | /* Can only change if privileged. */ |
90f62cf3 | 365 | if (!__netlink_ns_capable(nsp, &init_user_ns, CAP_NET_ADMIN)) { |
e70ab977 KC |
366 | err = EPERM; |
367 | goto out; | |
368 | } | |
369 | ||
f3c48ecc | 370 | mc_op = (enum proc_cn_mcast_op *)msg->data; |
9f46080c MH |
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 | } | |
e70ab977 KC |
382 | |
383 | out: | |
9f46080c MH |
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 | */ | |
392 | static int __init cn_proc_init(void) | |
393 | { | |
f3c48ecc VI |
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"); | |
9f46080c MH |
399 | return err; |
400 | } | |
401 | return 0; | |
402 | } | |
8297f2d9 | 403 | device_initcall(cn_proc_init); |