tjh.dev / kernel
Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
1
fork

Configure Feed

Select the types of activity you want to include in your feed.

char: ppdev: Fix a possible null-pointer dereference in pp_release()

In pp_release(), there is an if statement on line 730 to check whether
pp->pdev is NULL:
else if ((pp->flags & PP_CLAIMED) && pp->pdev && ...)

When pp->pdev is NULL, it is used on line 743:
info = &pp->pdev->port->ieee1284;
and on line 748:
parport_release(pp->pdev);

Thus, a possible null-pointer dereference may occur.

To fix this bug, pp->pdev is checked on line 740.

This bug is found by a static analysis tool STCheck written by us.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Link: https://lore.kernel.org/r/20190724090426.1401-1-baijiaju1990@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

authored by

Jia-Ju Bai and committed by
Greg Kroah-Hartman 7bdd9695 092f47c3

+1 -1
+1 -1
drivers/char/ppdev.c
··· 737 737 "negotiated back to compatibility mode because user-space forgot\n"); 738 738 } 739 739 740 - if (pp->flags & PP_CLAIMED) { 740 + if ((pp->flags & PP_CLAIMED) && pp->pdev) { 741 741 struct ieee1284_info *info; 742 742 743 743 info = &pp->pdev->port->ieee1284;