6.6-stable review patch. If anyone has any objections, please let me know.
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From: Johan Hovold johan@kernel.org
commit baadf2a5c26e802a46573eaad331b427b49aaa36 upstream.
The MOST subsystem has a non-standard registration function which frees the interface on registration failures and on deregistration.
This unsurprisingly leads to bugs in the MOST drivers, and a couple of recent changes turned a reference underflow and use-after-free in the USB driver into several double free and a use-after-free on late probe failures.
Fixes: 723de0f9171e ("staging: most: remove device from interface structure") Fixes: 4b1270902609 ("most: usb: Fix use-after-free in hdm_disconnect") Fixes: a8cc9e5fcb0e ("most: usb: hdm_probe: Fix calling put_device() before device initialization") Cc: stable@vger.kernel.org Cc: Christian Gromm christian.gromm@microchip.com Cc: Victoria Votokina Victoria.Votokina@kaspersky.com Signed-off-by: Johan Hovold johan@kernel.org Link: https://patch.msgid.link/20251029093029.28922-1-johan@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/most/most_usb.c | 14 +++++--------- 1 file changed, 5 insertions(+), 9 deletions(-)
--- a/drivers/most/most_usb.c +++ b/drivers/most/most_usb.c @@ -1058,7 +1058,7 @@ hdm_probe(struct usb_interface *interfac
ret = most_register_interface(&mdev->iface); if (ret) - goto err_free_busy_urbs; + return ret;
mutex_lock(&mdev->io_mutex); if (le16_to_cpu(usb_dev->descriptor.idProduct) == USB_DEV_ID_OS81118 || @@ -1068,8 +1068,7 @@ hdm_probe(struct usb_interface *interfac if (!mdev->dci) { mutex_unlock(&mdev->io_mutex); most_deregister_interface(&mdev->iface); - ret = -ENOMEM; - goto err_free_busy_urbs; + return -ENOMEM; }
mdev->dci->dev.init_name = "dci"; @@ -1078,18 +1077,15 @@ hdm_probe(struct usb_interface *interfac mdev->dci->dev.release = release_dci; if (device_register(&mdev->dci->dev)) { mutex_unlock(&mdev->io_mutex); + put_device(&mdev->dci->dev); most_deregister_interface(&mdev->iface); - ret = -ENOMEM; - goto err_free_dci; + return -ENOMEM; } mdev->dci->usb_device = mdev->usb_device; } mutex_unlock(&mdev->io_mutex); return 0; -err_free_dci: - put_device(&mdev->dci->dev); -err_free_busy_urbs: - kfree(mdev->busy_urbs); + err_free_ep_address: kfree(mdev->ep_address); err_free_cap: