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 #include <linux/pid_namespace.h> 34 35 #include <linux/cn_proc.h> 36 37 /* 38 * Size of a cn_msg followed by a proc_event structure. Since the 39 * sizeof struct cn_msg is a multiple of 4 bytes, but not 8 bytes, we 40 * add one 4-byte word to the size here, and then start the actual 41 * cn_msg structure 4 bytes into the stack buffer. The result is that 42 * the immediately following proc_event structure is aligned to 8 bytes. 43 */ 44 #define CN_PROC_MSG_SIZE (sizeof(struct cn_msg) + sizeof(struct proc_event) + 4) 45 46 /* See comment above; we test our assumption about sizeof struct cn_msg here. */ 47 static inline struct cn_msg *buffer_to_cn_msg(__u8 *buffer) 48 { 49 BUILD_BUG_ON(sizeof(struct cn_msg) != 20); 50 return (struct cn_msg *)(buffer + 4); 51 } 52 53 static atomic_t proc_event_num_listeners = ATOMIC_INIT(0); 54 static struct cb_id cn_proc_event_id = { CN_IDX_PROC, CN_VAL_PROC }; 55 56 /* proc_event_counts is used as the sequence number of the netlink message */ 57 static DEFINE_PER_CPU(__u32, proc_event_counts) = { 0 }; 58 59 static inline void get_seq(__u32 *ts, int *cpu) 60 { 61 preempt_disable(); 62 *ts = __this_cpu_inc_return(proc_event_counts) - 1; 63 *cpu = smp_processor_id(); 64 preempt_enable(); 65 } 66 67 void proc_fork_connector(struct task_struct *task) 68 { 69 struct cn_msg *msg; 70 struct proc_event *ev; 71 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); 72 struct timespec ts; 73 struct task_struct *parent; 74 75 if (atomic_read(&proc_event_num_listeners) < 1) 76 return; 77 78 msg = buffer_to_cn_msg(buffer); 79 ev = (struct proc_event *)msg->data; 80 memset(&ev->event_data, 0, sizeof(ev->event_data)); 81 get_seq(&msg->seq, &ev->cpu); 82 ktime_get_ts(&ts); /* get high res monotonic timestamp */ 83 ev->timestamp_ns = timespec_to_ns(&ts); 84 ev->what = PROC_EVENT_FORK; 85 rcu_read_lock(); 86 parent = rcu_dereference(task->real_parent); 87 ev->event_data.fork.parent_pid = parent->pid; 88 ev->event_data.fork.parent_tgid = parent->tgid; 89 rcu_read_unlock(); 90 ev->event_data.fork.child_pid = task->pid; 91 ev->event_data.fork.child_tgid = task->tgid; 92 93 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id)); 94 msg->ack = 0; /* not used */ 95 msg->len = sizeof(*ev); 96 msg->flags = 0; /* not used */ 97 /* If cn_netlink_send() failed, the data is not sent */ 98 cn_netlink_send(msg, 0, CN_IDX_PROC, GFP_KERNEL); 99 } 100 101 void proc_exec_connector(struct task_struct *task) 102 { 103 struct cn_msg *msg; 104 struct proc_event *ev; 105 struct timespec ts; 106 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); 107 108 if (atomic_read(&proc_event_num_listeners) < 1) 109 return; 110 111 msg = buffer_to_cn_msg(buffer); 112 ev = (struct proc_event *)msg->data; 113 memset(&ev->event_data, 0, sizeof(ev->event_data)); 114 get_seq(&msg->seq, &ev->cpu); 115 ktime_get_ts(&ts); /* get high res monotonic timestamp */ 116 ev->timestamp_ns = timespec_to_ns(&ts); 117 ev->what = PROC_EVENT_EXEC; 118 ev->event_data.exec.process_pid = task->pid; 119 ev->event_data.exec.process_tgid = task->tgid; 120 121 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id)); 122 msg->ack = 0; /* not used */ 123 msg->len = sizeof(*ev); 124 msg->flags = 0; /* not used */ 125 cn_netlink_send(msg, 0, CN_IDX_PROC, GFP_KERNEL); 126 } 127 128 void proc_id_connector(struct task_struct *task, int which_id) 129 { 130 struct cn_msg *msg; 131 struct proc_event *ev; 132 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); 133 struct timespec ts; 134 const struct cred *cred; 135 136 if (atomic_read(&proc_event_num_listeners) < 1) 137 return; 138 139 msg = buffer_to_cn_msg(buffer); 140 ev = (struct proc_event *)msg->data; 141 memset(&ev->event_data, 0, sizeof(ev->event_data)); 142 ev->what = which_id; 143 ev->event_data.id.process_pid = task->pid; 144 ev->event_data.id.process_tgid = task->tgid; 145 rcu_read_lock(); 146 cred = __task_cred(task); 147 if (which_id == PROC_EVENT_UID) { 148 ev->event_data.id.r.ruid = from_kuid_munged(&init_user_ns, cred->uid); 149 ev->event_data.id.e.euid = from_kuid_munged(&init_user_ns, cred->euid); 150 } else if (which_id == PROC_EVENT_GID) { 151 ev->event_data.id.r.rgid = from_kgid_munged(&init_user_ns, cred->gid); 152 ev->event_data.id.e.egid = from_kgid_munged(&init_user_ns, cred->egid); 153 } else { 154 rcu_read_unlock(); 155 return; 156 } 157 rcu_read_unlock(); 158 get_seq(&msg->seq, &ev->cpu); 159 ktime_get_ts(&ts); /* get high res monotonic timestamp */ 160 ev->timestamp_ns = timespec_to_ns(&ts); 161 162 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id)); 163 msg->ack = 0; /* not used */ 164 msg->len = sizeof(*ev); 165 msg->flags = 0; /* not used */ 166 cn_netlink_send(msg, 0, CN_IDX_PROC, GFP_KERNEL); 167 } 168 169 void proc_sid_connector(struct task_struct *task) 170 { 171 struct cn_msg *msg; 172 struct proc_event *ev; 173 struct timespec ts; 174 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); 175 176 if (atomic_read(&proc_event_num_listeners) < 1) 177 return; 178 179 msg = buffer_to_cn_msg(buffer); 180 ev = (struct proc_event *)msg->data; 181 memset(&ev->event_data, 0, sizeof(ev->event_data)); 182 get_seq(&msg->seq, &ev->cpu); 183 ktime_get_ts(&ts); /* get high res monotonic timestamp */ 184 ev->timestamp_ns = timespec_to_ns(&ts); 185 ev->what = PROC_EVENT_SID; 186 ev->event_data.sid.process_pid = task->pid; 187 ev->event_data.sid.process_tgid = task->tgid; 188 189 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id)); 190 msg->ack = 0; /* not used */ 191 msg->len = sizeof(*ev); 192 msg->flags = 0; /* not used */ 193 cn_netlink_send(msg, 0, CN_IDX_PROC, GFP_KERNEL); 194 } 195 196 void proc_ptrace_connector(struct task_struct *task, int ptrace_id) 197 { 198 struct cn_msg *msg; 199 struct proc_event *ev; 200 struct timespec ts; 201 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); 202 203 if (atomic_read(&proc_event_num_listeners) < 1) 204 return; 205 206 msg = buffer_to_cn_msg(buffer); 207 ev = (struct proc_event *)msg->data; 208 memset(&ev->event_data, 0, sizeof(ev->event_data)); 209 get_seq(&msg->seq, &ev->cpu); 210 ktime_get_ts(&ts); /* get high res monotonic timestamp */ 211 ev->timestamp_ns = timespec_to_ns(&ts); 212 ev->what = PROC_EVENT_PTRACE; 213 ev->event_data.ptrace.process_pid = task->pid; 214 ev->event_data.ptrace.process_tgid = task->tgid; 215 if (ptrace_id == PTRACE_ATTACH) { 216 ev->event_data.ptrace.tracer_pid = current->pid; 217 ev->event_data.ptrace.tracer_tgid = current->tgid; 218 } else if (ptrace_id == PTRACE_DETACH) { 219 ev->event_data.ptrace.tracer_pid = 0; 220 ev->event_data.ptrace.tracer_tgid = 0; 221 } else 222 return; 223 224 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id)); 225 msg->ack = 0; /* not used */ 226 msg->len = sizeof(*ev); 227 msg->flags = 0; /* not used */ 228 cn_netlink_send(msg, 0, CN_IDX_PROC, GFP_KERNEL); 229 } 230 231 void proc_comm_connector(struct task_struct *task) 232 { 233 struct cn_msg *msg; 234 struct proc_event *ev; 235 struct timespec ts; 236 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); 237 238 if (atomic_read(&proc_event_num_listeners) < 1) 239 return; 240 241 msg = buffer_to_cn_msg(buffer); 242 ev = (struct proc_event *)msg->data; 243 memset(&ev->event_data, 0, sizeof(ev->event_data)); 244 get_seq(&msg->seq, &ev->cpu); 245 ktime_get_ts(&ts); /* get high res monotonic timestamp */ 246 ev->timestamp_ns = timespec_to_ns(&ts); 247 ev->what = PROC_EVENT_COMM; 248 ev->event_data.comm.process_pid = task->pid; 249 ev->event_data.comm.process_tgid = task->tgid; 250 get_task_comm(ev->event_data.comm.comm, task); 251 252 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id)); 253 msg->ack = 0; /* not used */ 254 msg->len = sizeof(*ev); 255 msg->flags = 0; /* not used */ 256 cn_netlink_send(msg, 0, CN_IDX_PROC, GFP_KERNEL); 257 } 258 259 void proc_coredump_connector(struct task_struct *task) 260 { 261 struct cn_msg *msg; 262 struct proc_event *ev; 263 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); 264 struct timespec ts; 265 266 if (atomic_read(&proc_event_num_listeners) < 1) 267 return; 268 269 msg = buffer_to_cn_msg(buffer); 270 ev = (struct proc_event *)msg->data; 271 memset(&ev->event_data, 0, sizeof(ev->event_data)); 272 get_seq(&msg->seq, &ev->cpu); 273 ktime_get_ts(&ts); /* get high res monotonic timestamp */ 274 ev->timestamp_ns = timespec_to_ns(&ts); 275 ev->what = PROC_EVENT_COREDUMP; 276 ev->event_data.coredump.process_pid = task->pid; 277 ev->event_data.coredump.process_tgid = task->tgid; 278 279 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id)); 280 msg->ack = 0; /* not used */ 281 msg->len = sizeof(*ev); 282 msg->flags = 0; /* not used */ 283 cn_netlink_send(msg, 0, CN_IDX_PROC, GFP_KERNEL); 284 } 285 286 void proc_exit_connector(struct task_struct *task) 287 { 288 struct cn_msg *msg; 289 struct proc_event *ev; 290 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); 291 struct timespec ts; 292 293 if (atomic_read(&proc_event_num_listeners) < 1) 294 return; 295 296 msg = buffer_to_cn_msg(buffer); 297 ev = (struct proc_event *)msg->data; 298 memset(&ev->event_data, 0, sizeof(ev->event_data)); 299 get_seq(&msg->seq, &ev->cpu); 300 ktime_get_ts(&ts); /* get high res monotonic timestamp */ 301 ev->timestamp_ns = timespec_to_ns(&ts); 302 ev->what = PROC_EVENT_EXIT; 303 ev->event_data.exit.process_pid = task->pid; 304 ev->event_data.exit.process_tgid = task->tgid; 305 ev->event_data.exit.exit_code = task->exit_code; 306 ev->event_data.exit.exit_signal = task->exit_signal; 307 308 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id)); 309 msg->ack = 0; /* not used */ 310 msg->len = sizeof(*ev); 311 msg->flags = 0; /* not used */ 312 cn_netlink_send(msg, 0, CN_IDX_PROC, GFP_KERNEL); 313 } 314 315 /* 316 * Send an acknowledgement message to userspace 317 * 318 * Use 0 for success, EFOO otherwise. 319 * Note: this is the negative of conventional kernel error 320 * values because it's not being returned via syscall return 321 * mechanisms. 322 */ 323 static void cn_proc_ack(int err, int rcvd_seq, int rcvd_ack) 324 { 325 struct cn_msg *msg; 326 struct proc_event *ev; 327 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); 328 struct timespec ts; 329 330 if (atomic_read(&proc_event_num_listeners) < 1) 331 return; 332 333 msg = buffer_to_cn_msg(buffer); 334 ev = (struct proc_event *)msg->data; 335 memset(&ev->event_data, 0, sizeof(ev->event_data)); 336 msg->seq = rcvd_seq; 337 ktime_get_ts(&ts); /* get high res monotonic timestamp */ 338 ev->timestamp_ns = timespec_to_ns(&ts); 339 ev->cpu = -1; 340 ev->what = PROC_EVENT_NONE; 341 ev->event_data.ack.err = err; 342 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id)); 343 msg->ack = rcvd_ack + 1; 344 msg->len = sizeof(*ev); 345 msg->flags = 0; /* not used */ 346 cn_netlink_send(msg, 0, CN_IDX_PROC, GFP_KERNEL); 347 } 348 349 /** 350 * cn_proc_mcast_ctl 351 * @data: message sent from userspace via the connector 352 */ 353 static void cn_proc_mcast_ctl(struct cn_msg *msg, 354 struct netlink_skb_parms *nsp) 355 { 356 enum proc_cn_mcast_op *mc_op = NULL; 357 int err = 0; 358 359 if (msg->len != sizeof(*mc_op)) 360 return; 361 362 /* 363 * Events are reported with respect to the initial pid 364 * and user namespaces so ignore requestors from 365 * other namespaces. 366 */ 367 if ((current_user_ns() != &init_user_ns) || 368 (task_active_pid_ns(current) != &init_pid_ns)) 369 return; 370 371 /* Can only change if privileged. */ 372 if (!__netlink_ns_capable(nsp, &init_user_ns, CAP_NET_ADMIN)) { 373 err = EPERM; 374 goto out; 375 } 376 377 mc_op = (enum proc_cn_mcast_op *)msg->data; 378 switch (*mc_op) { 379 case PROC_CN_MCAST_LISTEN: 380 atomic_inc(&proc_event_num_listeners); 381 break; 382 case PROC_CN_MCAST_IGNORE: 383 atomic_dec(&proc_event_num_listeners); 384 break; 385 default: 386 err = EINVAL; 387 break; 388 } 389 390 out: 391 cn_proc_ack(err, msg->seq, msg->ack); 392 } 393 394 /* 395 * cn_proc_init - initialization entry point 396 * 397 * Adds the connector callback to the connector driver. 398 */ 399 static int __init cn_proc_init(void) 400 { 401 int err = cn_add_callback(&cn_proc_event_id, 402 "cn_proc", 403 &cn_proc_mcast_ctl); 404 if (err) { 405 pr_warn("cn_proc failed to register\n"); 406 return err; 407 } 408 return 0; 409 } 410 411 module_init(cn_proc_init); 412