misc: nsm: pin the module while the device is open

misc_open() installs a misc driver's file operations with fops_get(),
which pins file_operations::owner before replacing the file's f_op.  The
NSM misc device leaves nsm_dev_fops.owner unset, so opening /dev/nsm does
not take a module reference on the nsm driver.

If the driver is built as a module, an open file descriptor can therefore
survive rmmod of the module that provides its ioctl callbacks.  A later
ioctl through that descriptor can call into unloaded module text.

Set nsm_dev_fops.owner to THIS_MODULE so the misc core holds the module
while any /dev/nsm file descriptor is open, matching the lifetime
expectation for the installed file operations.

Fixes: b9873755a6c8 ("misc: Add Nitro Secure Module driver")
Cc: stable <stable@kernel.org>
Signed-off-by: Xu Rao <raoxu@uniontech.com>
Link: https://patch.msgid.link/BE6951D13B5E5513+20260713055523.3193089-1-raoxu@uniontech.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

0 files changed, 0 insertions, 0 deletions