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Commit 257d632c authored by Hardik Arya's avatar Hardik Arya Committed by Manoj Prabhu B
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diag: Add protection while accessing socket info's handle 



Currently, there is a possibility of passing invalid NULL handle
to selinux function after closing the channel. The patch adds
protection while accessing socket info's handle.

CRs-Fixed: 2111893
Change-Id: I94515cc52352446d61a710ed1c09818a78c39f46
Signed-off-by: default avatarHardik Arya <harya@codeaurora.org>
Signed-off-by: default avatarManoj Prabhu B <bmanoj@codeaurora.org>
parent 45eab650

drivers/char/diag/diagfwd_socket.c

+34 −3
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/* Copyright (c) 2015-2018, The Linux Foundation. All rights reserved.

/* Copyright (c) 2015-2019, The Linux Foundation. All rights reserved.

 */



#include <linux/slab.h>
@@ -511,9 +511,10 @@ static void __socket_close_channel(struct diag_socket_info *info) 
	info->hdl->sk->sk_data_ready = NULL;

	info->hdl->sk->sk_error_report = NULL;

	write_unlock_bh(&info->hdl->sk->sk_callback_lock);

	mutex_lock(&info->socket_info_mutex);

	sock_release(info->hdl);

	info->hdl = NULL;



	mutex_unlock(&info->socket_info_mutex);

	cancel_work_sync(&info->read_work);

	wake_up_interruptible(&info->read_wait_q);
@@ -714,13 +715,28 @@ static int diag_socket_read(void *ctxt, unsigned char *buf, int buf_len) 
		read_msg.msg_name = &src_addr;

		read_msg.msg_namelen = sizeof(src_addr);



		if (info->port_type != PORT_TYPE_SERVER) {

			mutex_lock(&info->socket_info_mutex);

			if (!info->hdl) {

				DIAG_LOG(DIAG_DEBUG_PERIPHERALS,

				"%s closing read thread\n",

					info->name);

				mutex_unlock(&info->socket_info_mutex);

				goto fail;

			}

		}

		err =  info->hdl->ops->ioctl(info->hdl, TIOCINQ,

					(unsigned long)&pkt_len);

		if (err || pkt_len < 0)

		if (err || pkt_len < 0) {

			if (info->port_type != PORT_TYPE_SERVER)

				mutex_unlock(&info->socket_info_mutex);

			break;

		}



		if (pkt_len > bytes_remaining) {

			buf_full = 1;

			if (info->port_type != PORT_TYPE_SERVER)

				mutex_unlock(&info->socket_info_mutex);

			break;

		}
@@ -730,6 +746,8 @@ static int diag_socket_read(void *ctxt, unsigned char *buf, int buf_len) 


		read_len = kernel_recvmsg(info->hdl, &read_msg, &iov, 1,

					  pkt_len, MSG_DONTWAIT);

		if (info->port_type != PORT_TYPE_SERVER)

			mutex_unlock(&info->socket_info_mutex);

		if (unlikely(read_len == -ENETRESET)) {

			mutex_lock(channel_mutex);

			diagfwd_channel_read_done(info->fwd_ctxt, buf, 0);
@@ -837,7 +855,16 @@ static int diag_socket_write(void *ctxt, unsigned char *buf, int len) 
	write_msg.msg_name = &info->remote_addr;

	write_msg.msg_namelen = sizeof(info->remote_addr);

	write_msg.msg_flags |= MSG_DONTWAIT;

	if (info->port_type != PORT_TYPE_SERVER) {

		mutex_lock(&info->socket_info_mutex);

		if (!info->hdl) {

			mutex_unlock(&info->socket_info_mutex);

			return -ENODEV;

		}

	}

	write_len = kernel_sendmsg(info->hdl, &write_msg, &iov, 1, len);

	if (info->port_type != PORT_TYPE_SERVER)

		mutex_unlock(&info->socket_info_mutex);

	if (write_len < 0) {

		err = write_len;

		/*
@@ -935,6 +962,8 @@ static void __diag_socket_init(struct diag_socket_info *info) 
		break;

	}



	if (info->port_type == PORT_TYPE_CLIENT)

		mutex_init(&info->socket_info_mutex);

	info->svc_id = DIAG_SVC_ID;

	info->ins_id = ins_base + ins_offset;

	info->inited = 1;
@@ -1092,6 +1121,8 @@ static void __diag_socket_exit(struct diag_socket_info *info) 
	if (info->hdl)

		sock_release(info->hdl);

	info->hdl = NULL;

	if (info->port_type == PORT_TYPE_CLIENT)

		mutex_destroy(&info->socket_info_mutex);

	if (info->wq)

		destroy_workqueue(info->wq);

}

drivers/char/diag/diagfwd_socket.h

+2 −1
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

/* Copyright (c) 2015-2018, The Linux Foundation. All rights reserved.

/* Copyright (c) 2015-2019, The Linux Foundation. All rights reserved.

 */



#ifndef DIAGFWD_SOCKET_H
@@ -49,6 +49,7 @@ struct diag_socket_info { 
	struct work_struct read_work;

	struct diagfwd_info *fwd_ctxt;

	wait_queue_head_t read_wait_q;

	struct mutex socket_info_mutex;

};