This is a note to let you know that I've just added the patch titled

comedi: Fix memory leak in compat_insnlist()

to my char-misc git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git in the char-misc-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From bb509a6ffed2c8b0950f637ab5779aa818ed1596 Mon Sep 17 00:00:00 2001

From: Ian Abbott abbotti@mev.co.uk Date: Thu, 16 Sep 2021 15:50:23 +0100 Subject: comedi: Fix memory leak in compat_insnlist()

`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 gregkh@linuxfoundation.org Cc: linux-staging@lists.linux.dev Cc: stable@vger.kernel.org # 5.13+ Signed-off-by: Ian Abbott abbotti@mev.co.uk Link: https://lore.kernel.org/r/20210916145023.157479-1-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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; }