`compat_insnlist()` handles the 32-bit version of the `COMEDI_INSNLIST` ioctl (whenwhen `CONFIG_COMPAT` is enabled). It allocates memory to temporarily hold an array of `struct comedi_insn` converted from the 32-bit version in user space. This memory is only being freed if there is a fault while filling the array, otherwise it is leaked.
Add a call to `kfree()` to fix the leak.
Fixes: b8d47d881305 ("comedi: get rid of compat_alloc_user_space() mess in COMEDI_INSNLIST compat" Cc: Al Viro viro@zeniv.linux.org.uk Cc: Greg Kroah-Hartman greglh@linuxfoundation.org Cc: linux-staging@lists.linux.dev Cc: stable@vger.kernel.org # 5.13+ Signed-off-by: Ian Abbott abbotti@mev.co.uk --- N.B. Also need patches for 5.8+ from before comedi moved out of staging. --- drivers/comedi/comedi_fops.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/comedi/comedi_fops.c b/drivers/comedi/comedi_fops.c index df77b6bf5c64..763cea8418f8 100644 --- a/drivers/comedi/comedi_fops.c +++ b/drivers/comedi/comedi_fops.c @@ -3090,6 +3090,7 @@ static int compat_insnlist(struct file *file, unsigned long arg) mutex_lock(&dev->mutex); rc = do_insnlist_ioctl(dev, insns, insnlist32.n_insns, file); mutex_unlock(&dev->mutex); + kfree(insns); return rc; }