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 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);