Merge: CVE-2021-47101: asix: fix uninit-value in asix_mdio_read()

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/4639

```
JIRA: https://issues.redhat.com/browse/RHEL-28110
CVE: CVE-2021-47101

commits:
    asix: fix uninit-value in asix_mdio_read()
    net: asix: add proper error handling of usb read errors

Signed-off-by: Ken Cox <jkc@redhat.com>
```

Approved-by: José Ignacio Tornos Martínez <jtornosm@redhat.com>
Approved-by: Desnes Nunes <desnesn@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

Merged-by: Lucas Zampieri <lzampier@redhat.com>

Author: zampierilucas

drivers/net/usb/asix.h

@@ -192,8 +192,8 @@ extern const struct driver_info ax88172a_info;
 /* ASIX specific flags */
 #define FLAG_EEPROM_MAC		(1UL << 0)  /* init device MAC from eeprom */
 
-int asix_read_cmd(struct usbnet *dev, u8 cmd, u16 value, u16 index,
-		  u16 size, void *data, int in_pm);
+int __must_check asix_read_cmd(struct usbnet *dev, u8 cmd, u16 value, u16 index,
+			       u16 size, void *data, int in_pm);
 
 int asix_write_cmd(struct usbnet *dev, u8 cmd, u16 value, u16 index,
 		   u16 size, void *data, int in_pm);

drivers/net/usb/asix_common.c

@@ -9,8 +9,8 @@
 
 #include "asix.h"
 
-int asix_read_cmd(struct usbnet *dev, u8 cmd, u16 value, u16 index,
-		  u16 size, void *data, int in_pm)
+int __must_check asix_read_cmd(struct usbnet *dev, u8 cmd, u16 value, u16 index,
+			       u16 size, void *data, int in_pm)
 {
 	int ret;
 	int (*fn)(struct usbnet *, u8, u8, u16, u16, void *, u16);
@@ -25,9 +25,12 @@ int asix_read_cmd(struct usbnet *dev, u8 cmd, u16 value, u16 index,
 	ret = fn(dev, cmd, USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
 		 value, index, data, size);
 
-	if (unlikely(ret < 0))
+	if (unlikely(ret < size)) {
+		ret = ret < 0 ? ret : -ENODATA;
+
 		netdev_warn(dev->net, "Failed to read reg index 0x%04x: %d\n",
 			    index, ret);
+	}
 
 	return ret;
 }
@@ -577,8 +580,12 @@ int asix_mdio_read_nopm(struct net_device *netdev, int phy_id, int loc)
 		return ret;
 	}
 
-	asix_read_cmd(dev, AX_CMD_READ_MII_REG, phy_id,
-		      (__u16)loc, 2, &res, 1);
+	ret = asix_read_cmd(dev, AX_CMD_READ_MII_REG, phy_id,
+			    (__u16)loc, 2, &res, 1);
+	if (ret < 0) {
+		mutex_unlock(&dev->phy_mutex);
+		return ret;
+	}
 	asix_set_hw_mii(dev, 1);
 	mutex_unlock(&dev->phy_mutex);
 

drivers/net/usb/asix_devices.c

@@ -756,7 +756,12 @@ static int ax88772_bind(struct usbnet *dev, struct usb_interface *intf)
 	priv->phy_addr = ret;
 	priv->embd_phy = ((priv->phy_addr & 0x1f) == 0x10);
 
-	asix_read_cmd(dev, AX_CMD_STATMNGSTS_REG, 0, 0, 1, &chipcode, 0);
+	ret = asix_read_cmd(dev, AX_CMD_STATMNGSTS_REG, 0, 0, 1, &chipcode, 0);
+	if (ret < 0) {
+		netdev_dbg(dev->net, "Failed to read STATMNGSTS_REG: %d\n", ret);
+		return ret;
+	}
+
 	chipcode &= AX_CHIPCODE_MASK;
 
 	ret = (chipcode == AX_AX88772_CHIPCODE) ? ax88772_hw_reset(dev, 0) :
@@ -925,11 +930,21 @@ static int ax88178_reset(struct usbnet *dev)
 	int gpio0 = 0;
 	u32 phyid;
 
-	asix_read_cmd(dev, AX_CMD_READ_GPIOS, 0, 0, 1, &status, 0);
+	ret = asix_read_cmd(dev, AX_CMD_READ_GPIOS, 0, 0, 1, &status, 0);
+	if (ret < 0) {
+		netdev_dbg(dev->net, "Failed to read GPIOS: %d\n", ret);
+		return ret;
+	}
+
 	netdev_dbg(dev->net, "GPIO Status: 0x%04x\n", status);
 
 	asix_write_cmd(dev, AX_CMD_WRITE_ENABLE, 0, 0, 0, NULL, 0);
-	asix_read_cmd(dev, AX_CMD_READ_EEPROM, 0x0017, 0, 2, &eeprom, 0);
+	ret = asix_read_cmd(dev, AX_CMD_READ_EEPROM, 0x0017, 0, 2, &eeprom, 0);
+	if (ret < 0) {
+		netdev_dbg(dev->net, "Failed to read EEPROM: %d\n", ret);
+		return ret;
+	}
+
 	asix_write_cmd(dev, AX_CMD_WRITE_DISABLE, 0, 0, 0, NULL, 0);
 
 	netdev_dbg(dev->net, "EEPROM index 0x17 is 0x%04x\n", eeprom);