Orange Pi5 kernel

// 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>
#include <linux/local_lock.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 };
 
/* local_event.count is used as the sequence number of the netlink message */
struct local_event {
<------>local_lock_t lock;
<------>__u32 count;
};
static DEFINE_PER_CPU(struct local_event, local_event) = {
<------>.lock = INIT_LOCAL_LOCK(lock),
};
 
static inline void send_msg(struct cn_msg *msg)
{
<------>local_lock(&local_event.lock);
 
<------>msg->seq = __this_cpu_inc_return(local_event.count) - 1;
<------>((struct proc_event *)msg->data)->cpu = smp_processor_id();
 
<------>/*
<------> * local_lock() disables preemption 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);
 
<------>local_unlock(&local_event.lock);
}
 
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);