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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, GwanYeong Kim <gy741.kim@gmail.com>,
        Shuah Khan <skhan@linuxfoundation.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.3 149/193] usbip: tools: Fix read_usb_vudc_device() error path handling
Date:   Mon, 11 Nov 2019 19:28:51 +0100
Message-Id: <20191111181512.142337434@linuxfoundation.org>
In-Reply-To: <20191111181459.850623879@linuxfoundation.org>
References: <20191111181459.850623879@linuxfoundation.org>
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From: GwanYeong Kim <gy741.kim@gmail.com>

[ Upstream commit 28df0642abbf6d66908a2858922a7e4b21cdd8c2 ]

This isn't really accurate right. fread() doesn't always
return 0 in error. It could return < number of elements
and set errno.

Signed-off-by: GwanYeong Kim <gy741.kim@gmail.com>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20191018032223.4644-1-gy741.kim@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/usb/usbip/libsrc/usbip_device_driver.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/tools/usb/usbip/libsrc/usbip_device_driver.c b/tools/usb/usbip/libsrc/usbip_device_driver.c
index 5a3726eb44abc..b237a43e62990 100644
--- a/tools/usb/usbip/libsrc/usbip_device_driver.c
+++ b/tools/usb/usbip/libsrc/usbip_device_driver.c
@@ -69,7 +69,7 @@ int read_usb_vudc_device(struct udev_device *sdev, struct usbip_usb_device *dev)
 	FILE *fd = NULL;
 	struct udev_device *plat;
 	const char *speed;
-	int ret = 0;
+	size_t ret;
 
 	plat = udev_device_get_parent(sdev);
 	path = udev_device_get_syspath(plat);
@@ -79,8 +79,10 @@ int read_usb_vudc_device(struct udev_device *sdev, struct usbip_usb_device *dev)
 	if (!fd)
 		return -1;
 	ret = fread((char *) &descr, sizeof(descr), 1, fd);
-	if (ret < 0)
+	if (ret != 1) {
+		err("Cannot read vudc device descr file: %s", strerror(errno));
 		goto err;
+	}
 	fclose(fd);
 
 	copy_descr_attr(dev, &descr, bDeviceClass);
-- 
2.20.1