linux/drivers/connector/cn_proc.c
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   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
  41static atomic_t proc_event_num_listeners = ATOMIC_INIT(0);
  42static 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 */
  45static DEFINE_PER_CPU(__u32, proc_event_counts) = { 0 };
  46
  47static 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
  55void 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
  87void 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
 112void 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
 151void 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
 176void 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
 209void 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
 235void proc_exit_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_EXIT;
 251        ev->event_data.exit.process_pid = task->pid;
 252        ev->event_data.exit.process_tgid = task->tgid;
 253        ev->event_data.exit.exit_code = task->exit_code;
 254        ev->event_data.exit.exit_signal = task->exit_signal;
 255
 256        memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 257        msg->ack = 0; /* not used */
 258        msg->len = sizeof(*ev);
 259        cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 260}
 261
 262/*
 263 * Send an acknowledgement message to userspace
 264 *
 265 * Use 0 for success, EFOO otherwise.
 266 * Note: this is the negative of conventional kernel error
 267 * values because it's not being returned via syscall return
 268 * mechanisms.
 269 */
 270static void cn_proc_ack(int err, int rcvd_seq, int rcvd_ack)
 271{
 272        struct cn_msg *msg;
 273        struct proc_event *ev;
 274        __u8 buffer[CN_PROC_MSG_SIZE];
 275        struct timespec ts;
 276
 277        if (atomic_read(&proc_event_num_listeners) < 1)
 278                return;
 279
 280        msg = (struct cn_msg *)buffer;
 281        ev = (struct proc_event *)msg->data;
 282        msg->seq = rcvd_seq;
 283        ktime_get_ts(&ts); /* get high res monotonic timestamp */
 284        put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
 285        ev->cpu = -1;
 286        ev->what = PROC_EVENT_NONE;
 287        ev->event_data.ack.err = err;
 288        memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 289        msg->ack = rcvd_ack + 1;
 290        msg->len = sizeof(*ev);
 291        cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 292}
 293
 294/**
 295 * cn_proc_mcast_ctl
 296 * @data: message sent from userspace via the connector
 297 */
 298static void cn_proc_mcast_ctl(struct cn_msg *msg,
 299                              struct netlink_skb_parms *nsp)
 300{
 301        enum proc_cn_mcast_op *mc_op = NULL;
 302        int err = 0;
 303
 304        if (msg->len != sizeof(*mc_op))
 305                return;
 306
 307        /* 
 308         * Events are reported with respect to the initial pid
 309         * and user namespaces so ignore requestors from
 310         * other namespaces.
 311         */
 312        if ((current_user_ns() != &init_user_ns) ||
 313            (task_active_pid_ns(current) != &init_pid_ns))
 314                return;
 315
 316        mc_op = (enum proc_cn_mcast_op *)msg->data;
 317        switch (*mc_op) {
 318        case PROC_CN_MCAST_LISTEN:
 319                atomic_inc(&proc_event_num_listeners);
 320                break;
 321        case PROC_CN_MCAST_IGNORE:
 322                atomic_dec(&proc_event_num_listeners);
 323                break;
 324        default:
 325                err = EINVAL;
 326                break;
 327        }
 328        cn_proc_ack(err, msg->seq, msg->ack);
 329}
 330
 331/*
 332 * cn_proc_init - initialization entry point
 333 *
 334 * Adds the connector callback to the connector driver.
 335 */
 336static int __init cn_proc_init(void)
 337{
 338        int err = cn_add_callback(&cn_proc_event_id,
 339                                  "cn_proc",
 340                                  &cn_proc_mcast_ctl);
 341        if (err) {
 342                pr_warn("cn_proc failed to register\n");
 343                return err;
 344        }
 345        return 0;
 346}
 347
 348module_init(cn_proc_init);
 349
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