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linux/drivers/connector/cn_proc.c
Thomas Gleixner 1a59d1b8e0 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details you
  should have received a copy of the gnu general public license along
  with this program if not write to the free software foundation inc
  59 temple place suite 330 boston ma 02111 1307 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1334 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:35 -07:00

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* cn_proc.c - process events connector
*
* Copyright (C) Matt Helsley, IBM Corp. 2005
* Based on cn_fork.c by Guillaume Thouvenin <guillaume.thouvenin@bull.net>
* Original copyright notice follows:
* Copyright (C) 2005 BULL SA.
*/
#include <linux/kernel.h>
#include <linux/ktime.h>
#include <linux/init.h>
#include <linux/connector.h>
#include <linux/gfp.h>
#include <linux/ptrace.h>
#include <linux/atomic.h>
#include <linux/pid_namespace.h>
#include <linux/cn_proc.h>
/*
* Size of a cn_msg followed by a proc_event structure. Since the
* sizeof struct cn_msg is a multiple of 4 bytes, but not 8 bytes, we
* add one 4-byte word to the size here, and then start the actual
* cn_msg structure 4 bytes into the stack buffer. The result is that
* the immediately following proc_event structure is aligned to 8 bytes.
*/
#define CN_PROC_MSG_SIZE (sizeof(struct cn_msg) + sizeof(struct proc_event) + 4)
/* See comment above; we test our assumption about sizeof struct cn_msg here. */
static inline struct cn_msg *buffer_to_cn_msg(__u8 *buffer)
{
BUILD_BUG_ON(sizeof(struct cn_msg) != 20);
return (struct cn_msg *)(buffer + 4);
}
static atomic_t proc_event_num_listeners = ATOMIC_INIT(0);
static struct cb_id cn_proc_event_id = { CN_IDX_PROC, CN_VAL_PROC };
/* proc_event_counts is used as the sequence number of the netlink message */
static DEFINE_PER_CPU(__u32, proc_event_counts) = { 0 };
static inline void send_msg(struct cn_msg *msg)
{
preempt_disable();
msg->seq = __this_cpu_inc_return(proc_event_counts) - 1;
((struct proc_event *)msg->data)->cpu = smp_processor_id();
/*
* Preemption remains disabled during send to ensure the messages are
* ordered according to their sequence numbers.
*
* If cn_netlink_send() fails, the data is not sent.
*/
cn_netlink_send(msg, 0, CN_IDX_PROC, GFP_NOWAIT);
preempt_enable();
}
void proc_fork_connector(struct task_struct *task)
{
struct cn_msg *msg;
struct proc_event *ev;
__u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
struct task_struct *parent;
if (atomic_read(&proc_event_num_listeners) < 1)
return;
msg = buffer_to_cn_msg(buffer);
ev = (struct proc_event *)msg->data;
memset(&ev->event_data, 0, sizeof(ev->event_data));
ev->timestamp_ns = ktime_get_ns();
ev->what = PROC_EVENT_FORK;
rcu_read_lock();
parent = rcu_dereference(task->real_parent);
ev->event_data.fork.parent_pid = parent->pid;
ev->event_data.fork.parent_tgid = parent->tgid;
rcu_read_unlock();
ev->event_data.fork.child_pid = task->pid;
ev->event_data.fork.child_tgid = task->tgid;
memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
msg->ack = 0; /* not used */
msg->len = sizeof(*ev);
msg->flags = 0; /* not used */
send_msg(msg);
}
void proc_exec_connector(struct task_struct *task)
{
struct cn_msg *msg;
struct proc_event *ev;
__u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
if (atomic_read(&proc_event_num_listeners) < 1)
return;
msg = buffer_to_cn_msg(buffer);
ev = (struct proc_event *)msg->data;
memset(&ev->event_data, 0, sizeof(ev->event_data));
ev->timestamp_ns = ktime_get_ns();
ev->what = PROC_EVENT_EXEC;
ev->event_data.exec.process_pid = task->pid;
ev->event_data.exec.process_tgid = task->tgid;
memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
msg->ack = 0; /* not used */
msg->len = sizeof(*ev);
msg->flags = 0; /* not used */
send_msg(msg);
}
void proc_id_connector(struct task_struct *task, int which_id)
{
struct cn_msg *msg;
struct proc_event *ev;
__u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
const struct cred *cred;
if (atomic_read(&proc_event_num_listeners) < 1)
return;
msg = buffer_to_cn_msg(buffer);
ev = (struct proc_event *)msg->data;
memset(&ev->event_data, 0, sizeof(ev->event_data));
ev->what = which_id;
ev->event_data.id.process_pid = task->pid;
ev->event_data.id.process_tgid = task->tgid;
rcu_read_lock();
cred = __task_cred(task);
if (which_id == PROC_EVENT_UID) {
ev->event_data.id.r.ruid = from_kuid_munged(&init_user_ns, cred->uid);
ev->event_data.id.e.euid = from_kuid_munged(&init_user_ns, cred->euid);
} else if (which_id == PROC_EVENT_GID) {
ev->event_data.id.r.rgid = from_kgid_munged(&init_user_ns, cred->gid);
ev->event_data.id.e.egid = from_kgid_munged(&init_user_ns, cred->egid);
} else {
rcu_read_unlock();
return;
}
rcu_read_unlock();
ev->timestamp_ns = ktime_get_ns();
memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
msg->ack = 0; /* not used */
msg->len = sizeof(*ev);
msg->flags = 0; /* not used */
send_msg(msg);
}
void proc_sid_connector(struct task_struct *task)
{
struct cn_msg *msg;
struct proc_event *ev;
__u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
if (atomic_read(&proc_event_num_listeners) < 1)
return;
msg = buffer_to_cn_msg(buffer);
ev = (struct proc_event *)msg->data;
memset(&ev->event_data, 0, sizeof(ev->event_data));
ev->timestamp_ns = ktime_get_ns();
ev->what = PROC_EVENT_SID;
ev->event_data.sid.process_pid = task->pid;
ev->event_data.sid.process_tgid = task->tgid;
memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
msg->ack = 0; /* not used */
msg->len = sizeof(*ev);
msg->flags = 0; /* not used */
send_msg(msg);
}
void proc_ptrace_connector(struct task_struct *task, int ptrace_id)
{
struct cn_msg *msg;
struct proc_event *ev;
__u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
if (atomic_read(&proc_event_num_listeners) < 1)
return;
msg = buffer_to_cn_msg(buffer);
ev = (struct proc_event *)msg->data;
memset(&ev->event_data, 0, sizeof(ev->event_data));
ev->timestamp_ns = ktime_get_ns();
ev->what = PROC_EVENT_PTRACE;
ev->event_data.ptrace.process_pid = task->pid;
ev->event_data.ptrace.process_tgid = task->tgid;
if (ptrace_id == PTRACE_ATTACH) {
ev->event_data.ptrace.tracer_pid = current->pid;
ev->event_data.ptrace.tracer_tgid = current->tgid;
} else if (ptrace_id == PTRACE_DETACH) {
ev->event_data.ptrace.tracer_pid = 0;
ev->event_data.ptrace.tracer_tgid = 0;
} else
return;
memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
msg->ack = 0; /* not used */
msg->len = sizeof(*ev);
msg->flags = 0; /* not used */
send_msg(msg);
}
void proc_comm_connector(struct task_struct *task)
{
struct cn_msg *msg;
struct proc_event *ev;
__u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
if (atomic_read(&proc_event_num_listeners) < 1)
return;
msg = buffer_to_cn_msg(buffer);
ev = (struct proc_event *)msg->data;
memset(&ev->event_data, 0, sizeof(ev->event_data));
ev->timestamp_ns = ktime_get_ns();
ev->what = PROC_EVENT_COMM;
ev->event_data.comm.process_pid = task->pid;
ev->event_data.comm.process_tgid = task->tgid;
get_task_comm(ev->event_data.comm.comm, task);
memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
msg->ack = 0; /* not used */
msg->len = sizeof(*ev);
msg->flags = 0; /* not used */
send_msg(msg);
}
void proc_coredump_connector(struct task_struct *task)
{
struct cn_msg *msg;
struct proc_event *ev;
struct task_struct *parent;
__u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
if (atomic_read(&proc_event_num_listeners) < 1)
return;
msg = buffer_to_cn_msg(buffer);
ev = (struct proc_event *)msg->data;
memset(&ev->event_data, 0, sizeof(ev->event_data));
ev->timestamp_ns = ktime_get_ns();
ev->what = PROC_EVENT_COREDUMP;
ev->event_data.coredump.process_pid = task->pid;
ev->event_data.coredump.process_tgid = task->tgid;
rcu_read_lock();
if (pid_alive(task)) {
parent = rcu_dereference(task->real_parent);
ev->event_data.coredump.parent_pid = parent->pid;
ev->event_data.coredump.parent_tgid = parent->tgid;
}
rcu_read_unlock();
memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
msg->ack = 0; /* not used */
msg->len = sizeof(*ev);
msg->flags = 0; /* not used */
send_msg(msg);
}
void proc_exit_connector(struct task_struct *task)
{
struct cn_msg *msg;
struct proc_event *ev;
struct task_struct *parent;
__u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
if (atomic_read(&proc_event_num_listeners) < 1)
return;
msg = buffer_to_cn_msg(buffer);
ev = (struct proc_event *)msg->data;
memset(&ev->event_data, 0, sizeof(ev->event_data));
ev->timestamp_ns = ktime_get_ns();
ev->what = PROC_EVENT_EXIT;
ev->event_data.exit.process_pid = task->pid;
ev->event_data.exit.process_tgid = task->tgid;
ev->event_data.exit.exit_code = task->exit_code;
ev->event_data.exit.exit_signal = task->exit_signal;
rcu_read_lock();
if (pid_alive(task)) {
parent = rcu_dereference(task->real_parent);
ev->event_data.exit.parent_pid = parent->pid;
ev->event_data.exit.parent_tgid = parent->tgid;
}
rcu_read_unlock();
memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
msg->ack = 0; /* not used */
msg->len = sizeof(*ev);
msg->flags = 0; /* not used */
send_msg(msg);
}
/*
* Send an acknowledgement message to userspace
*
* Use 0 for success, EFOO otherwise.
* Note: this is the negative of conventional kernel error
* values because it's not being returned via syscall return
* mechanisms.
*/
static void cn_proc_ack(int err, int rcvd_seq, int rcvd_ack)
{
struct cn_msg *msg;
struct proc_event *ev;
__u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
if (atomic_read(&proc_event_num_listeners) < 1)
return;
msg = buffer_to_cn_msg(buffer);
ev = (struct proc_event *)msg->data;
memset(&ev->event_data, 0, sizeof(ev->event_data));
msg->seq = rcvd_seq;
ev->timestamp_ns = ktime_get_ns();
ev->cpu = -1;
ev->what = PROC_EVENT_NONE;
ev->event_data.ack.err = err;
memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
msg->ack = rcvd_ack + 1;
msg->len = sizeof(*ev);
msg->flags = 0; /* not used */
send_msg(msg);
}
/**
* cn_proc_mcast_ctl
* @data: message sent from userspace via the connector
*/
static void cn_proc_mcast_ctl(struct cn_msg *msg,
struct netlink_skb_parms *nsp)
{
enum proc_cn_mcast_op *mc_op = NULL;
int err = 0;
if (msg->len != sizeof(*mc_op))
return;
/*
* Events are reported with respect to the initial pid
* and user namespaces so ignore requestors from
* other namespaces.
*/
if ((current_user_ns() != &init_user_ns) ||
(task_active_pid_ns(current) != &init_pid_ns))
return;
/* Can only change if privileged. */
if (!__netlink_ns_capable(nsp, &init_user_ns, CAP_NET_ADMIN)) {
err = EPERM;
goto out;
}
mc_op = (enum proc_cn_mcast_op *)msg->data;
switch (*mc_op) {
case PROC_CN_MCAST_LISTEN:
atomic_inc(&proc_event_num_listeners);
break;
case PROC_CN_MCAST_IGNORE:
atomic_dec(&proc_event_num_listeners);
break;
default:
err = EINVAL;
break;
}
out:
cn_proc_ack(err, msg->seq, msg->ack);
}
/*
* cn_proc_init - initialization entry point
*
* Adds the connector callback to the connector driver.
*/
static int __init cn_proc_init(void)
{
int err = cn_add_callback(&cn_proc_event_id,
"cn_proc",
&cn_proc_mcast_ctl);
if (err) {
pr_warn("cn_proc failed to register\n");
return err;
}
return 0;
}
device_initcall(cn_proc_init);
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