5.4-stable review patch. If anyone has any objections, please let me know.
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From: Jun Yan jerrysteve1101@gmail.com
commit 7a3d76a0b60b3f6fc3375e4de2174bab43f64545 upstream.
Fix the regression introduced by commit d8c6edfa3f4e ("USB: usblp: don't call usb_set_interface if there's a single alt"), which causes that unsupported protocols can also be set via ioctl when the num_altsetting of the device is 1.
Move the check for protocol support to the earlier stage.
Fixes: d8c6edfa3f4e ("USB: usblp: don't call usb_set_interface if there's a single alt") Cc: stable stable@kernel.org Signed-off-by: Jun Yan jerrysteve1101@gmail.com Link: https://lore.kernel.org/r/20241212143852.671889-1-jerrysteve1101@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/class/usblp.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
--- a/drivers/usb/class/usblp.c +++ b/drivers/usb/class/usblp.c @@ -1337,11 +1337,12 @@ static int usblp_set_protocol(struct usb if (protocol < USBLP_FIRST_PROTOCOL || protocol > USBLP_LAST_PROTOCOL) return -EINVAL;
+ alts = usblp->protocol[protocol].alt_setting; + if (alts < 0) + return -EINVAL; + /* Don't unnecessarily set the interface if there's a single alt. */ if (usblp->intf->num_altsetting > 1) { - alts = usblp->protocol[protocol].alt_setting; - if (alts < 0) - return -EINVAL; r = usb_set_interface(usblp->dev, usblp->ifnum, alts); if (r < 0) { printk(KERN_ERR "usblp: can't set desired altsetting %d on interface %d\n",