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media: rc: Ensure registered is cleared in error path

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If rc_register_device() fails, ensure that registered is not set to true.
If lirc_register() succeeded, then userspace could have an open file
descriptor open. This leads to a use-after-free.

lirc_unregister() must be called with registered = false, else there is a
possibility that an fd is open and polling, which would never return
POLLERR unless registered is false.

Note that registered must be changed under dev->lock, many functions
read registered under lock (e.g. lirc_ioctl).

Fixes: dccc0c3ddf ("media: rc: fix race between unregister and urb/irq callbacks")
Signed-off-by: Sean Young <sean@mess.org>
Cc: stable@vger.kernel.org
Acked-by: Hans Verkuil <hverkuil+cisco@kernel.org>
This commit is contained in:
Sean Young 2026-08-07 11:50:22 +01:00
parent 2f35a044d0
commit 37efd09ba2
1 changed files with 12 additions and 4 deletions
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16
drivers/media/rc/rc-main.c
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@ -1934,7 +1934,8 @@ int rc_register_device(struct rc_dev *dev)
goto out_raw; goto out_raw;
} }
dev->registered = true; scoped_guard(mutex, &dev->lock)
dev->registered = true;
rc = device_add(&dev->dev); rc = device_add(&dev->dev);
if (rc) if (rc)
@ -1954,7 +1955,7 @@ int rc_register_device(struct rc_dev *dev)
if (dev->allowed_protocols != RC_PROTO_BIT_CEC) { if (dev->allowed_protocols != RC_PROTO_BIT_CEC) {
rc = lirc_register(dev); rc = lirc_register(dev);
if (rc < 0) if (rc < 0)
goto out_dev; goto out_lirc;
} }
if (dev->driver_type != RC_DRIVER_IR_RAW_TX) { if (dev->driver_type != RC_DRIVER_IR_RAW_TX) {
@ -1977,11 +1978,18 @@ int rc_register_device(struct rc_dev *dev)
out_rx: out_rx:
rc_free_rx_device(dev); rc_free_rx_device(dev);
out_lirc: out_lirc:
if (dev->allowed_protocols != RC_PROTO_BIT_CEC) scoped_guard(mutex, &dev->lock)
dev->registered = false;
if (device_is_registered(&dev->lirc_dev))
lirc_unregister(dev); lirc_unregister(dev);
out_dev:
device_del(&dev->dev); device_del(&dev->dev);
/* registered already cleared above */
goto out_free_table;
out_rx_free: out_rx_free:
scoped_guard(mutex, &dev->lock)
dev->registered = false;
out_free_table:
ir_free_table(&dev->rc_map); ir_free_table(&dev->rc_map);
out_raw: out_raw:
ida_free(&rc_ida, minor); ida_free(&rc_ida, minor);