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