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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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