net: asix: add proper error handling of usb read errors

Syzbot once again hit uninit value in asix driver. The problem still the
same -- asix_read_cmd() reads less bytes, than was requested by caller.

Since all read requests are performed via asix_read_cmd() let's catch
usb related error there and add __must_check notation to be sure all
callers actually check return value.

So, this patch adds sanity check inside asix_read_cmd(), that simply
checks if bytes read are not less, than was requested and adds missing
error handling of asix_read_cmd() all across the driver code.

Fixes: d9fe64e51114 ("net: asix: Add in_pm parameter")
Reported-and-tested-by: syzbot+6ca9f7867b77c2d316ac@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Tested-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/usb/asix.h b/drivers/net/usb/asix.h
index 2a1e31d..4334aaf 100644 (file)
--- a/drivers/net/usb/asix.h
+++ b/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);

diff --git a/drivers/net/usb/asix_common.c b/drivers/net/usb/asix_common.c
index 7168297..5248052 100644 (file)
--- a/drivers/net/usb/asix_common.c
+++ b/drivers/net/usb/asix_common.c
@@ -11,8 +11,8 @@
 
 #define AX_HOST_EN_RETRIES     30
 
-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);
@@ -27,9 +27,12 @@ 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;
 }
@@ -79,7 +82,7 @@ static int asix_check_host_enable(struct usbnet *dev, int in_pm)
                                    0, 0, 1, &smsr, in_pm);
                if (ret == -ENODEV)
                        break;
-               else if (ret < sizeof(smsr))
+               else if (ret < 0)
                        continue;
                else if (smsr & AX_HOST_EN)
                        break;
@@ -579,8 +582,12 @@ 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);
 

diff --git a/drivers/net/usb/asix_devices.c b/drivers/net/usb/asix_devices.c
index 9b72334..6ea44e5 100644 (file)
--- a/drivers/net/usb/asix_devices.c
+++ b/drivers/net/usb/asix_devices.c
@@ -755,7 +755,12 @@ 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) :
@@ -919,11 +924,21 @@ 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);