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