drivers/connector/cn_proc.c

   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);