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/kernel.h> 26 #include <linux/ktime.h> 27 #include <linux/init.h> 28 #include <linux/connector.h> 29 #include <linux/gfp.h> 30 #include <linux/ptrace.h> 31 #include <linux/atomic.h> 32 #include <linux/pid_namespace.h> 33 34 #include <linux/cn_proc.h> 35 36 /* 37 * Size of a cn_msg followed by a proc_event structure. Since the 38 * sizeof struct cn_msg is a multiple of 4 bytes, but not 8 bytes, we 39 * add one 4-byte word to the size here, and then start the actual 40 * cn_msg structure 4 bytes into the stack buffer. The result is that 41 * the immediately following proc_event structure is aligned to 8 bytes. 42 */ 43 #define CN_PROC_MSG_SIZE (sizeof(struct cn_msg) + sizeof(struct proc_event) + 4) 44 45 /* See comment above; we test our assumption about sizeof struct cn_msg here. */ 46 static inline struct cn_msg *buffer_to_cn_msg(__u8 *buffer) 47 { 48 BUILD_BUG_ON(sizeof(struct cn_msg) != 20); 49 return (struct cn_msg *)(buffer + 4); 50 } 51 52 static atomic_t proc_event_num_listeners = ATOMIC_INIT(0); 53 static struct cb_id cn_proc_event_id = { CN_IDX_PROC, CN_VAL_PROC }; 54 55 /* proc_event_counts is used as the sequence number of the netlink message */ 56 static DEFINE_PER_CPU(__u32, proc_event_counts) = { 0 }; 57 58 static inline void send_msg(struct cn_msg *msg) 59 { 60 preempt_disable(); 61 62 msg->seq = __this_cpu_inc_return(proc_event_counts) - 1; 63 ((struct proc_event *)msg->data)->cpu = smp_processor_id(); 64 65 /* 66 * Preemption remains disabled during send to ensure the messages are 67 * ordered according to their sequence numbers. 68 * 69 * If cn_netlink_send() fails, the data is not sent. 70 */ 71 cn_netlink_send(msg, 0, CN_IDX_PROC, GFP_NOWAIT); 72 73 preempt_enable(); 74 } 75 76 void proc_fork_connector(struct task_struct *task) 77 { 78 struct cn_msg *msg; 79 struct proc_event *ev; 80 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); 81 struct task_struct *parent; 82 83 if (atomic_read(&proc_event_num_listeners) < 1) 84 return; 85 86 msg = buffer_to_cn_msg(buffer); 87 ev = (struct proc_event *)msg->data; 88 memset(&ev->event_data, 0, sizeof(ev->event_data)); 89 ev->timestamp_ns = ktime_get_ns(); 90 ev->what = PROC_EVENT_FORK; 91 rcu_read_lock(); 92 parent = rcu_dereference(task->real_parent); 93 ev->event_data.fork.parent_pid = parent->pid; 94 ev->event_data.fork.parent_tgid = parent->tgid; 95 rcu_read_unlock(); 96 ev->event_data.fork.child_pid = task->pid; 97 ev->event_data.fork.child_tgid = task->tgid; 98 99 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id)); 100 msg->ack = 0; /* not used */ 101 msg->len = sizeof(*ev); 102 msg->flags = 0; /* not used */ 103 send_msg(msg); 104 } 105 106 void proc_exec_connector(struct task_struct *task) 107 { 108 struct cn_msg *msg; 109 struct proc_event *ev; 110 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); 111 112 if (atomic_read(&proc_event_num_listeners) < 1) 113 return; 114 115 msg = buffer_to_cn_msg(buffer); 116 ev = (struct proc_event *)msg->data; 117 memset(&ev->event_data, 0, sizeof(ev->event_data)); 118 ev->timestamp_ns = ktime_get_ns(); 119 ev->what = PROC_EVENT_EXEC; 120 ev->event_data.exec.process_pid = task->pid; 121 ev->event_data.exec.process_tgid = task->tgid; 122 123 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id)); 124 msg->ack = 0; /* not used */ 125 msg->len = sizeof(*ev); 126 msg->flags = 0; /* not used */ 127 send_msg(msg); 128 } 129 130 void proc_id_connector(struct task_struct *task, int which_id) 131 { 132 struct cn_msg *msg; 133 struct proc_event *ev; 134 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); 135 const struct cred *cred; 136 137 if (atomic_read(&proc_event_num_listeners) < 1) 138 return; 139 140 msg = buffer_to_cn_msg(buffer); 141 ev = (struct proc_event *)msg->data; 142 memset(&ev->event_data, 0, sizeof(ev->event_data)); 143 ev->what = which_id; 144 ev->event_data.id.process_pid = task->pid; 145 ev->event_data.id.process_tgid = task->tgid; 146 rcu_read_lock(); 147 cred = __task_cred(task); 148 if (which_id == PROC_EVENT_UID) { 149 ev->event_data.id.r.ruid = from_kuid_munged(&init_user_ns, cred->uid); 150 ev->event_data.id.e.euid = from_kuid_munged(&init_user_ns, cred->euid); 151 } else if (which_id == PROC_EVENT_GID) { 152 ev->event_data.id.r.rgid = from_kgid_munged(&init_user_ns, cred->gid); 153 ev->event_data.id.e.egid = from_kgid_munged(&init_user_ns, cred->egid); 154 } else { 155 rcu_read_unlock(); 156 return; 157 } 158 rcu_read_unlock(); 159 ev->timestamp_ns = ktime_get_ns(); 160 161 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id)); 162 msg->ack = 0; /* not used */ 163 msg->len = sizeof(*ev); 164 msg->flags = 0; /* not used */ 165 send_msg(msg); 166 } 167 168 void proc_sid_connector(struct task_struct *task) 169 { 170 struct cn_msg *msg; 171 struct proc_event *ev; 172 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); 173 174 if (atomic_read(&proc_event_num_listeners) < 1) 175 return; 176 177 msg = buffer_to_cn_msg(buffer); 178 ev = (struct proc_event *)msg->data; 179 memset(&ev->event_data, 0, sizeof(ev->event_data)); 180 ev->timestamp_ns = ktime_get_ns(); 181 ev->what = PROC_EVENT_SID; 182 ev->event_data.sid.process_pid = task->pid; 183 ev->event_data.sid.process_tgid = task->tgid; 184 185 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id)); 186 msg->ack = 0; /* not used */ 187 msg->len = sizeof(*ev); 188 msg->flags = 0; /* not used */ 189 send_msg(msg); 190 } 191 192 void proc_ptrace_connector(struct task_struct *task, int ptrace_id) 193 { 194 struct cn_msg *msg; 195 struct proc_event *ev; 196 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); 197 198 if (atomic_read(&proc_event_num_listeners) < 1) 199 return; 200 201 msg = buffer_to_cn_msg(buffer); 202 ev = (struct proc_event *)msg->data; 203 memset(&ev->event_data, 0, sizeof(ev->event_data)); 204 ev->timestamp_ns = ktime_get_ns(); 205 ev->what = PROC_EVENT_PTRACE; 206 ev->event_data.ptrace.process_pid = task->pid; 207 ev->event_data.ptrace.process_tgid = task->tgid; 208 if (ptrace_id == PTRACE_ATTACH) { 209 ev->event_data.ptrace.tracer_pid = current->pid; 210 ev->event_data.ptrace.tracer_tgid = current->tgid; 211 } else if (ptrace_id == PTRACE_DETACH) { 212 ev->event_data.ptrace.tracer_pid = 0; 213 ev->event_data.ptrace.tracer_tgid = 0; 214 } else 215 return; 216 217 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id)); 218 msg->ack = 0; /* not used */ 219 msg->len = sizeof(*ev); 220 msg->flags = 0; /* not used */ 221 send_msg(msg); 222 } 223 224 void proc_comm_connector(struct task_struct *task) 225 { 226 struct cn_msg *msg; 227 struct proc_event *ev; 228 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); 229 230 if (atomic_read(&proc_event_num_listeners) < 1) 231 return; 232 233 msg = buffer_to_cn_msg(buffer); 234 ev = (struct proc_event *)msg->data; 235 memset(&ev->event_data, 0, sizeof(ev->event_data)); 236 ev->timestamp_ns = ktime_get_ns(); 237 ev->what = PROC_EVENT_COMM; 238 ev->event_data.comm.process_pid = task->pid; 239 ev->event_data.comm.process_tgid = task->tgid; 240 get_task_comm(ev->event_data.comm.comm, task); 241 242 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id)); 243 msg->ack = 0; /* not used */ 244 msg->len = sizeof(*ev); 245 msg->flags = 0; /* not used */ 246 send_msg(msg); 247 } 248 249 void proc_coredump_connector(struct task_struct *task) 250 { 251 struct cn_msg *msg; 252 struct proc_event *ev; 253 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); 254 255 if (atomic_read(&proc_event_num_listeners) < 1) 256 return; 257 258 msg = buffer_to_cn_msg(buffer); 259 ev = (struct proc_event *)msg->data; 260 memset(&ev->event_data, 0, sizeof(ev->event_data)); 261 ev->timestamp_ns = ktime_get_ns(); 262 ev->what = PROC_EVENT_COREDUMP; 263 ev->event_data.coredump.process_pid = task->pid; 264 ev->event_data.coredump.process_tgid = task->tgid; 265 ev->event_data.coredump.parent_pid = task->real_parent->pid; 266 ev->event_data.coredump.parent_tgid = task->real_parent->tgid; 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 } 274 275 void proc_exit_connector(struct task_struct *task) 276 { 277 struct cn_msg *msg; 278 struct proc_event *ev; 279 __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); 280 281 if (atomic_read(&proc_event_num_listeners) < 1) 282 return; 283 284 msg = buffer_to_cn_msg(buffer); 285 ev = (struct proc_event *)msg->data; 286 memset(&ev->event_data, 0, sizeof(ev->event_data)); 287 ev->timestamp_ns = ktime_get_ns(); 288 ev->what = PROC_EVENT_EXIT; 289 ev->event_data.exit.process_pid = task->pid; 290 ev->event_data.exit.process_tgid = task->tgid; 291 ev->event_data.exit.exit_code = task->exit_code; 292 ev->event_data.exit.exit_signal = task->exit_signal; 293 ev->event_data.exit.parent_pid = task->real_parent->pid; 294 ev->event_data.exit.parent_tgid = task->real_parent->tgid; 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 */ 311 static 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 */ 339 static 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 } 375 376 out: 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 */ 385 static 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 } 396 device_initcall(cn_proc_init); 397