diff options
Diffstat (limited to 'drivers/connector/cn_proc.c')
| -rw-r--r-- | drivers/connector/cn_proc.c | 403 |
1 files changed, 403 insertions, 0 deletions
diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c new file mode 100644 index 000000000..ccac1c453 --- /dev/null +++ b/drivers/connector/cn_proc.c @@ -0,0 +1,403 @@ +// 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_is_in_init_pid_ns(current)) + 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); |