6.6-stable review patch. If anyone has any objections, please let me know.
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From: Yuichiro Tsuji yuichtsu@amazon.com
[ Upstream commit 24ef2f53c07f273bad99173e27ee88d44d135b1c ]
Syzbot reported shift-out-of-bounds exception on MDIO bus initialization.
The PHY address should be masked to 5 bits (0-31). Without this mask, invalid PHY addresses could be used, potentially causing issues with MDIO bus operations.
Fix this by masking the PHY address with 0x1f (31 decimal) to ensure it stays within the valid range.
Fixes: 4faff70959d5 ("net: usb: asix_devices: add phy_mask for ax88772 mdio bus") Reported-by: syzbot+20537064367a0f98d597@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=20537064367a0f98d597 Tested-by: syzbot+20537064367a0f98d597@syzkaller.appspotmail.com Signed-off-by: Yuichiro Tsuji yuichtsu@amazon.com Reviewed-by: Andrew Lunn andrew@lunn.ch Link: https://patch.msgid.link/20250818084541.1958-1-yuichtsu@amazon.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/usb/asix_devices.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/usb/asix_devices.c b/drivers/net/usb/asix_devices.c index 6a2567a67902..f4340d4ef7ee 100644 --- a/drivers/net/usb/asix_devices.c +++ b/drivers/net/usb/asix_devices.c @@ -676,7 +676,7 @@ static int ax88772_init_mdio(struct usbnet *dev) priv->mdio->read = &asix_mdio_bus_read; priv->mdio->write = &asix_mdio_bus_write; priv->mdio->name = "Asix MDIO Bus"; - priv->mdio->phy_mask = ~(BIT(priv->phy_addr) | BIT(AX_EMBD_PHY_ADDR)); + priv->mdio->phy_mask = ~(BIT(priv->phy_addr & 0x1f) | BIT(AX_EMBD_PHY_ADDR)); /* mii bus name is usb-<usb bus number>-<usb device number> */ snprintf(priv->mdio->id, MII_BUS_ID_SIZE, "usb-%03d:%03d", dev->udev->bus->busnum, dev->udev->devnum);