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From:   gregkh@linuxfoundation.org
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
        Shuah Khan <skhan@linuxfoundation.org>
Subject: [PATCH 4.9 41/78] usbip: fix vudc to check for stream socket
Date:   Mon, 15 Mar 2021 14:52:04 +0100
Message-Id: <20210315135213.415412176@linuxfoundation.org>
In-Reply-To: <20210315135212.060847074@linuxfoundation.org>
References: <20210315135212.060847074@linuxfoundation.org>
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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

From: Shuah Khan <skhan@linuxfoundation.org>

commit 6801854be94fe8819b3894979875ea31482f5658 upstream.

Fix usbip_sockfd_store() to validate the passed in file descriptor is
a stream socket. If the file descriptor passed was a SOCK_DGRAM socket,
sock_recvmsg() can't detect end of stream.

Cc: stable@vger.kernel.org
Suggested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/387a670316002324113ac7ea1e8b53f4085d0c95.1615171203.git.skhan@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/usbip/vudc_sysfs.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

--- a/drivers/usb/usbip/vudc_sysfs.c
+++ b/drivers/usb/usbip/vudc_sysfs.c
@@ -24,6 +24,7 @@
 #include <linux/usb/ch9.h>
 #include <linux/sysfs.h>
 #include <linux/kthread.h>
+#include <linux/file.h>
 #include <linux/byteorder/generic.h>
 
 #include "usbip_common.h"
@@ -150,6 +151,13 @@ static ssize_t store_sockfd(struct devic
 			goto unlock_ud;
 		}
 
+		if (socket->type != SOCK_STREAM) {
+			dev_err(dev, "Expecting SOCK_STREAM - found %d",
+				socket->type);
+			ret = -EINVAL;
+			goto sock_err;
+		}
+
 		udc->ud.tcp_socket = socket;
 
 		spin_unlock_irq(&udc->ud.lock);
@@ -189,6 +197,8 @@ static ssize_t store_sockfd(struct devic
 
 	return count;
 
+sock_err:
+	sockfd_put(socket);
 unlock_ud:
 	spin_unlock_irq(&udc->ud.lock);
 unlock: