Re: [PATCH RFT] net: asix: add proper error handling of usb read errors

Oleksij Rempel
2022-01-05T14:15:57Z

On Wed, Jan 05, 2022 at 04:19:52PM +0300, Pavel Skripkin wrote:
> 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>

Thank you!

> ---
> drivers/net/usb/asix.h | 4 ++--
> drivers/net/usb/asix_common.c | 19 +++++++++++++------
> drivers/net/usb/asix_devices.c | 21 ++++++++++++++++++---
> 3 files changed, 33 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/net/usb/asix.h b/drivers/net/usb/asix.h
> index 2a1e31defe71..4334aafab59a 100644
> --- 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 71682970be58..524805285019 100644
> --- 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 4514d35ef4c4..6b2fbdf4e0fd 100644
> --- 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) :
> @@ -920,11 +925,21 @@ 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);
> --
> 2.34.1
>
>

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