diff options
| author | Jann Horn <jann@thejh.net> | 2016-10-30 23:19:24 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-11-10 15:24:02 +0100 |
| commit | b13d14339baaaa720e7e5448855f33ba501917aa (patch) | |
| tree | ad7a952596416c13e5a56c377d852497cc1248c4 | |
| parent | f6b2db084b65b9dc0f910bc48d5f77c0e5166dc6 (diff) | |
| download | lwn-b13d14339baaaa720e7e5448855f33ba501917aa.tar.gz lwn-b13d14339baaaa720e7e5448855f33ba501917aa.zip | |
ppdev: fix double-free of pp->pdev->name
free_pardevice() is called by parport_unregister_device() and already frees
pp->pdev->name, don't try to do it again.
This bug causes kernel crashes.
I found and verified this with KASAN and some added pr_emerg()s:
[ 60.316568] pp_release: pp->pdev->name == ffff88039cb264c0
[ 60.316692] free_pardevice: freeing par_dev->name at ffff88039cb264c0
[ 60.316706] pp_release: kfree(ffff88039cb264c0)
[ 60.316714] ==========================================================
[ 60.316722] BUG: Double free or freeing an invalid pointer
[ 60.316731] Unexpected shadow byte: 0xFB
[ 60.316801] Object at ffff88039cb264c0, in cache kmalloc-32 size: 32
[ 60.316813] Allocated:
[ 60.316824] PID = 1695
[ 60.316869] Freed:
[ 60.316880] PID = 1695
[ 60.316935] ==========================================================
Signed-off-by: Jann Horn <jann@thejh.net>
Acked-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/char/ppdev.c | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/drivers/char/ppdev.c b/drivers/char/ppdev.c index d23368874710..6af1ce04b3da 100644 --- a/drivers/char/ppdev.c +++ b/drivers/char/ppdev.c @@ -748,10 +748,7 @@ static int pp_release(struct inode *inode, struct file *file) } if (pp->pdev) { - const char *name = pp->pdev->name; - parport_unregister_device(pp->pdev); - kfree(name); pp->pdev = NULL; pr_debug(CHRDEV "%x: unregistered pardevice\n", minor); } |