1 files changed, 130 insertions, 38 deletions

diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c
index a782ce87715c..44b19e696176 100644
--- a/drivers/connector/cn_proc.c
+++ b/drivers/connector/cn_proc.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * cn_proc.c - process events connector
  *
@@ -5,21 +6,6 @@
  * Based on cn_fork.c by Guillaume Thouvenin <guillaume.thouvenin@bull.net>
  * Original copyright notice follows:
  * Copyright (C) 2005 BULL SA.
- *
- *
- * 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
  */
 
 #include <linux/kernel.h>
@@ -32,6 +18,7 @@
 #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
@@ -52,25 +39,79 @@ static inline struct cn_msg *buffer_to_cn_msg(__u8 *buffer)
 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 };
+/* 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)
 {
-	preempt_disable();
+	__u32 filter_data[2];
 
-	msg->seq = __this_cpu_inc_return(proc_event_counts) - 1;
+	local_lock(&local_event.lock);
+
+	msg->seq = __this_cpu_inc_return(local_event.count) - 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.
+	 * 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);
+	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;
+	}
+
+	cn_netlink_send_mult(msg, msg->len, 0, CN_IDX_PROC, GFP_NOWAIT,
+			     cn_filter, (void *)filter_data);
 
-	preempt_enable();
+	local_unlock(&local_event.lock);
 }
 
 void proc_fork_connector(struct task_struct *task)
@@ -250,6 +291,7 @@ 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)
@@ -263,6 +305,14 @@ void proc_coredump_connector(struct task_struct *task)
 	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);
@@ -274,6 +324,7 @@ 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)
@@ -289,6 +340,14 @@ void proc_exit_connector(struct task_struct *task)
 	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);
@@ -330,16 +389,17 @@ static void cn_proc_ack(int err, int rcvd_seq, int rcvd_ack)
 
 /**
  * cn_proc_mcast_ctl
- * @data: message sent from userspace via the connector
+ * @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 = NULL;
-	int err = 0;
-
-	if (msg->len != sizeof(*mc_op))
-		return;
+	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
@@ -347,22 +407,54 @@ static void cn_proc_mcast_ctl(struct cn_msg *msg,
 	 * other namespaces.
 	 */
 	if ((current_user_ns() != &init_user_ns) ||
-	    (task_active_pid_ns(current) != &init_pid_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;
+	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;
 	}
 
-	mc_op = (enum proc_cn_mcast_op *)msg->data;
-	switch (*mc_op) {
+	switch (mc_op) {
 	case PROC_CN_MCAST_LISTEN:
-		atomic_inc(&proc_event_num_listeners);
+		if (initial || (prev_mc_op != PROC_CN_MCAST_LISTEN))
+			atomic_inc(&proc_event_num_listeners);
 		break;
 	case PROC_CN_MCAST_IGNORE:
-		atomic_dec(&proc_event_num_listeners);
+		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;