// 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 int cn_filter(struct sock *dsk, struct sk_buff *skb, void *data) { __u32 what, exit_code, *ptr; enum proc_cn_mcast_op mc_op; uintptr_t val; if (!dsk || !dsk->sk_user_data || !data) return 0; ptr = (__u32 *)data; what = *ptr++; exit_code = *ptr; val = ((struct proc_input *)(dsk->sk_user_data))->event_type; mc_op = ((struct proc_input *)(dsk->sk_user_data))->mcast_op; if (mc_op == PROC_CN_MCAST_IGNORE) return 1; if ((__u32)val == PROC_EVENT_ALL) return 0; /* * Drop packet if we have to report only non-zero exit status * (PROC_EVENT_NONZERO_EXIT) and exit status is 0 */ if (((__u32)val & PROC_EVENT_NONZERO_EXIT) && (what == PROC_EVENT_EXIT)) { if (exit_code) return 0; } if ((__u32)val & what) return 0; return 1; } static inline void send_msg(struct cn_msg *msg) { __u32 filter_data[2]; 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. */ filter_data[0] = ((struct proc_event *)msg->data)->what; if (filter_data[0] == PROC_EVENT_EXIT) { filter_data[1] = ((struct proc_event *)msg->data)->event_data.exit.exit_code; } else { filter_data[1] = 0; } if (cn_netlink_send_mult(msg, msg->len, 0, CN_IDX_PROC, GFP_NOWAIT, cn_filter, (void *)filter_data) == -ESRCH) atomic_set(&proc_event_num_listeners, 0); 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 * @msg: message sent from userspace via the connector * @nsp: NETLINK_CB of the client's socket buffer */ static void cn_proc_mcast_ctl(struct cn_msg *msg, struct netlink_skb_parms *nsp) { enum proc_cn_mcast_op mc_op = 0, prev_mc_op = 0; struct proc_input *pinput = NULL; enum proc_cn_event ev_type = 0; int err = 0, initial = 0; struct sock *sk = NULL; /* * 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_is_in_init_pid_ns(current)) return; if (msg->len == sizeof(*pinput)) { pinput = (struct proc_input *)msg->data; mc_op = pinput->mcast_op; ev_type = pinput->event_type; } else if (msg->len == sizeof(mc_op)) { mc_op = *((enum proc_cn_mcast_op *)msg->data); ev_type = PROC_EVENT_ALL; } else { return; } ev_type = valid_event((enum proc_cn_event)ev_type); if (ev_type == PROC_EVENT_NONE) ev_type = PROC_EVENT_ALL; if (nsp->sk) { sk = nsp->sk; if (sk->sk_user_data == NULL) { sk->sk_user_data = kzalloc(sizeof(struct proc_input), GFP_KERNEL); if (sk->sk_user_data == NULL) { err = ENOMEM; goto out; } initial = 1; } else { prev_mc_op = ((struct proc_input *)(sk->sk_user_data))->mcast_op; } ((struct proc_input *)(sk->sk_user_data))->event_type = ev_type; ((struct proc_input *)(sk->sk_user_data))->mcast_op = mc_op; } switch (mc_op) { case PROC_CN_MCAST_LISTEN: if (initial || (prev_mc_op != PROC_CN_MCAST_LISTEN)) atomic_inc(&proc_event_num_listeners); break; case PROC_CN_MCAST_IGNORE: if (!initial && (prev_mc_op != PROC_CN_MCAST_IGNORE)) atomic_dec(&proc_event_num_listeners); ((struct proc_input *)(sk->sk_user_data))->event_type = PROC_EVENT_NONE; 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);