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 <asm/unaligned.h>
  36
  37 #include <linux/cn_proc.h>
  38
  39 #define CN_PROC_MSG_SIZE (sizeof(struct cn_msg) + sizeof(struct proc_event))
  40
  41 static atomic_t proc_event_num_listeners = ATOMIC_INIT(0);
  42 static struct cb_id cn_proc_event_id = { CN_IDX_PROC, CN_VAL_PROC };
  43
  44 /* proc_event_counts is used as the sequence number of the netlink message */
  45 static DEFINE_PER_CPU(__u32, proc_event_counts) = { 0 };
  46
  47 static inline void get_seq(__u32 *ts, int *cpu)
  48 {
  49         preempt_disable();
  50         *ts = __this_cpu_inc_return(proc_event_counts) - 1;
  51         *cpu = smp_processor_id();
  52         preempt_enable();
  53 }
  54
  55 void proc_fork_connector(struct task_struct *task)
  56 {
  57         struct cn_msg *msg;
  58         struct proc_event *ev;
  59         __u8 buffer[CN_PROC_MSG_SIZE];
  60         struct timespec ts;
  61         struct task_struct *parent;
  62
  63         if (atomic_read(&proc_event_num_listeners) < 1)
  64                 return;
  65
  66         msg = (struct cn_msg *)buffer;
  67         ev = (struct proc_event *)msg->data;
  68         get_seq(&msg->seq, &ev->cpu);
  69         ktime_get_ts(&ts); /* get high res monotonic timestamp */
  70         put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
  71         ev->what = PROC_EVENT_FORK;
  72         rcu_read_lock();
  73         parent = rcu_dereference(task->real_parent);
  74         ev->event_data.fork.parent_pid = parent->pid;
  75         ev->event_data.fork.parent_tgid = parent->tgid;
  76         rcu_read_unlock();
  77         ev->event_data.fork.child_pid = task->pid;
  78         ev->event_data.fork.child_tgid = task->tgid;
  79
  80         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
  81         msg->ack = 0; /* not used */
  82         msg->len = sizeof(*ev);
  83         /*  If cn_netlink_send() failed, the data is not sent */
  84         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
  85 }
  86
  87 void proc_exec_connector(struct task_struct *task)
  88 {
  89         struct cn_msg *msg;
  90         struct proc_event *ev;
  91         struct timespec ts;
  92         __u8 buffer[CN_PROC_MSG_SIZE];
  93
  94         if (atomic_read(&proc_event_num_listeners) < 1)
  95                 return;
  96
  97         msg = (struct cn_msg *)buffer;
  98         ev = (struct proc_event *)msg->data;
  99         get_seq(&msg->seq, &ev->cpu);
 100         ktime_get_ts(&ts); /* get high res monotonic timestamp */
 101         put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
 102         ev->what = PROC_EVENT_EXEC;
 103         ev->event_data.exec.process_pid = task->pid;
 104         ev->event_data.exec.process_tgid = task->tgid;
 105
 106         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 107         msg->ack = 0; /* not used */
 108         msg->len = sizeof(*ev);
 109         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 110 }
 111
 112 void proc_id_connector(struct task_struct *task, int which_id)
 113 {
 114         struct cn_msg *msg;
 115         struct proc_event *ev;
 116         __u8 buffer[CN_PROC_MSG_SIZE];
 117         struct timespec ts;
 118         const struct cred *cred;
 119
 120         if (atomic_read(&proc_event_num_listeners) < 1)
 121                 return;
 122
 123         msg = (struct cn_msg *)buffer;
 124         ev = (struct proc_event *)msg->data;
 125         ev->what = which_id;
 126         ev->event_data.id.process_pid = task->pid;
 127         ev->event_data.id.process_tgid = task->tgid;
 128         rcu_read_lock();
 129         cred = __task_cred(task);
 130         if (which_id == PROC_EVENT_UID) {
 131                 ev->event_data.id.r.ruid = from_kuid_munged(&init_user_ns, cred->uid);
 132                 ev->event_data.id.e.euid = from_kuid_munged(&init_user_ns, cred->euid);
 133         } else if (which_id == PROC_EVENT_GID) {
 134                 ev->event_data.id.r.rgid = from_kgid_munged(&init_user_ns, cred->gid);
 135                 ev->event_data.id.e.egid = from_kgid_munged(&init_user_ns, cred->egid);
 136         } else {
 137                 rcu_read_unlock();
 138                 return;
 139         }
 140         rcu_read_unlock();
 141         get_seq(&msg->seq, &ev->cpu);
 142         ktime_get_ts(&ts); /* get high res monotonic timestamp */
 143         put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
 144
 145         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 146         msg->ack = 0; /* not used */
 147         msg->len = sizeof(*ev);
 148         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 149 }
 150
 151 void proc_sid_connector(struct task_struct *task)
 152 {
 153         struct cn_msg *msg;
 154         struct proc_event *ev;
 155         struct timespec ts;
 156         __u8 buffer[CN_PROC_MSG_SIZE];
 157
 158         if (atomic_read(&proc_event_num_listeners) < 1)
 159                 return;
 160
 161         msg = (struct cn_msg *)buffer;
 162         ev = (struct proc_event *)msg->data;
 163         get_seq(&msg->seq, &ev->cpu);
 164         ktime_get_ts(&ts); /* get high res monotonic timestamp */
 165         put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
 166         ev->what = PROC_EVENT_SID;
 167         ev->event_data.sid.process_pid = task->pid;
 168         ev->event_data.sid.process_tgid = task->tgid;
 169
 170         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 171         msg->ack = 0; /* not used */
 172         msg->len = sizeof(*ev);
 173         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 174 }
 175
 176 void proc_ptrace_connector(struct task_struct *task, int ptrace_id)
 177 {
 178         struct cn_msg *msg;
 179         struct proc_event *ev;
 180         struct timespec ts;
 181         __u8 buffer[CN_PROC_MSG_SIZE];
 182
 183         if (atomic_read(&proc_event_num_listeners) < 1)
 184                 return;
 185
 186         msg = (struct cn_msg *)buffer;
 187         ev = (struct proc_event *)msg->data;
 188         get_seq(&msg->seq, &ev->cpu);
 189         ktime_get_ts(&ts); /* get high res monotonic timestamp */
 190         put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
 191         ev->what = PROC_EVENT_PTRACE;
 192         ev->event_data.ptrace.process_pid  = task->pid;
 193         ev->event_data.ptrace.process_tgid = task->tgid;
 194         if (ptrace_id == PTRACE_ATTACH) {
 195                 ev->event_data.ptrace.tracer_pid  = current->pid;
 196                 ev->event_data.ptrace.tracer_tgid = current->tgid;
 197         } else if (ptrace_id == PTRACE_DETACH) {
 198                 ev->event_data.ptrace.tracer_pid  = 0;
 199                 ev->event_data.ptrace.tracer_tgid = 0;
 200         } else
 201                 return;
 202
 203         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 204         msg->ack = 0; /* not used */
 205         msg->len = sizeof(*ev);
 206         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 207 }
 208
 209 void proc_comm_connector(struct task_struct *task)
 210 {
 211         struct cn_msg *msg;
 212         struct proc_event *ev;
 213         struct timespec ts;
 214         __u8 buffer[CN_PROC_MSG_SIZE];
 215
 216         if (atomic_read(&proc_event_num_listeners) < 1)
 217                 return;
 218
 219         msg = (struct cn_msg *)buffer;
 220         ev = (struct proc_event *)msg->data;
 221         get_seq(&msg->seq, &ev->cpu);
 222         ktime_get_ts(&ts); /* get high res monotonic timestamp */
 223         put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
 224         ev->what = PROC_EVENT_COMM;
 225         ev->event_data.comm.process_pid  = task->pid;
 226         ev->event_data.comm.process_tgid = task->tgid;
 227         get_task_comm(ev->event_data.comm.comm, task);
 228
 229         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 230         msg->ack = 0; /* not used */
 231         msg->len = sizeof(*ev);
 232         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 233 }
 234
 235 void proc_coredump_connector(struct task_struct *task)
 236 {
 237         struct cn_msg *msg;
 238         struct proc_event *ev;
 239         __u8 buffer[CN_PROC_MSG_SIZE];
 240         struct timespec ts;
 241
 242         if (atomic_read(&proc_event_num_listeners) < 1)
 243                 return;
 244
 245         msg = (struct cn_msg *)buffer;
 246         ev = (struct proc_event *)msg->data;
 247         get_seq(&msg->seq, &ev->cpu);
 248         ktime_get_ts(&ts); /* get high res monotonic timestamp */
 249         put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
 250         ev->what = PROC_EVENT_COREDUMP;
 251         ev->event_data.coredump.process_pid = task->pid;
 252         ev->event_data.coredump.process_tgid = task->tgid;
 253
 254         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 255         msg->ack = 0; /* not used */
 256         msg->len = sizeof(*ev);
 257         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 258 }
 259
 260 void proc_exit_connector(struct task_struct *task)
 261 {
 262         struct cn_msg *msg;
 263         struct proc_event *ev;
 264         __u8 buffer[CN_PROC_MSG_SIZE];
 265         struct timespec ts;
 266
 267         if (atomic_read(&proc_event_num_listeners) < 1)
 268                 return;
 269
 270         msg = (struct cn_msg *)buffer;
 271         ev = (struct proc_event *)msg->data;
 272         get_seq(&msg->seq, &ev->cpu);
 273         ktime_get_ts(&ts); /* get high res monotonic timestamp */
 274         put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
 275         ev->what = PROC_EVENT_EXIT;
 276         ev->event_data.exit.process_pid = task->pid;
 277         ev->event_data.exit.process_tgid = task->tgid;
 278         ev->event_data.exit.exit_code = task->exit_code;
 279         ev->event_data.exit.exit_signal = task->exit_signal;
 280
 281         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 282         msg->ack = 0; /* not used */
 283         msg->len = sizeof(*ev);
 284         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 285 }
 286
 287 /*
 288  * Send an acknowledgement message to userspace
 289  *
 290  * Use 0 for success, EFOO otherwise.
 291  * Note: this is the negative of conventional kernel error
 292  * values because it's not being returned via syscall return
 293  * mechanisms.
 294  */
 295 static void cn_proc_ack(int err, int rcvd_seq, int rcvd_ack)
 296 {
 297         struct cn_msg *msg;
 298         struct proc_event *ev;
 299         __u8 buffer[CN_PROC_MSG_SIZE];
 300         struct timespec ts;
 301
 302         if (atomic_read(&proc_event_num_listeners) < 1)
 303                 return;
 304
 305         msg = (struct cn_msg *)buffer;
 306         ev = (struct proc_event *)msg->data;
 307         msg->seq = rcvd_seq;
 308         ktime_get_ts(&ts); /* get high res monotonic timestamp */
 309         put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
 310         ev->cpu = -1;
 311         ev->what = PROC_EVENT_NONE;
 312         ev->event_data.ack.err = err;
 313         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 314         msg->ack = rcvd_ack + 1;
 315         msg->len = sizeof(*ev);
 316         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 317 }
 318
 319 /**
 320  * cn_proc_mcast_ctl
 321  * @data: message sent from userspace via the connector
 322  */
 323 static void cn_proc_mcast_ctl(struct cn_msg *msg,
 324                               struct netlink_skb_parms *nsp)
 325 {
 326         enum proc_cn_mcast_op *mc_op = NULL;
 327         int err = 0;
 328
 329         if (msg->len != sizeof(*mc_op))
 330                 return;
 331
 332         /*
 333          * Events are reported with respect to the initial pid
 334          * and user namespaces so ignore requestors from
 335          * other namespaces.
 336          */
 337         if ((current_user_ns() != &init_user_ns) ||
 338             (task_active_pid_ns(current) != &init_pid_ns))
 339                 return;
 340
 341         /* Can only change if privileged. */
 342         if (!capable(CAP_NET_ADMIN)) {
 343                 err = EPERM;
 344                 goto out;
 345         }
 346
 347         mc_op = (enum proc_cn_mcast_op *)msg->data;
 348         switch (*mc_op) {
 349         case PROC_CN_MCAST_LISTEN:
 350                 atomic_inc(&proc_event_num_listeners);
 351                 break;
 352         case PROC_CN_MCAST_IGNORE:
 353                 atomic_dec(&proc_event_num_listeners);
 354                 break;
 355         default:
 356                 err = EINVAL;
 357                 break;
 358         }
 359
 360 out:
 361         cn_proc_ack(err, msg->seq, msg->ack);
 362 }
 363
 364 /*
 365  * cn_proc_init - initialization entry point
 366  *
 367  * Adds the connector callback to the connector driver.
 368  */
 369 static int __init cn_proc_init(void)
 370 {
 371         int err = cn_add_callback(&cn_proc_event_id,
 372                                   "cn_proc",
 373                                   &cn_proc_mcast_ctl);
 374         if (err) {
 375                 pr_warn("cn_proc failed to register\n");
 376                 return err;
 377         }
 378         return 0;
 379 }
 380
 381 module_init(cn_proc_init);