From: Bernd Porr Date: Wed, 11 Dec 2013 16:06:15 +0000 (+0000) Subject: staging: comedi: fix result of memdup_user for user chanlist X-Git-Tag: v3.13.1~9 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=af7b2d49ef7b4171ef416b7ca2810834993afbca;p=thirdparty%2Fkernel%2Fstable.git staging: comedi: fix result of memdup_user for user chanlist commit e56b1401056288a725d50942ef300dcbed5e519a upstream. If the channel list is not set in userspace we get an error at PTR_ERR(async->cmd.chanlist). However, do_become_nonbusy(dev, s) cleans up this pointer which causes a kernel ooops. Setting the channel list in async to NULL and checking this in do_become_nonbusy prevents the oops. [Ian Abbott] Also do the same for the chanlist allocated in do_cmdtest_ioctl(). Signed-off-by: Bernd Porr Signed-off-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index f3d59e2a1152b..341decfb81d10 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -1425,6 +1425,7 @@ static int do_cmd_ioctl(struct comedi_device *dev, async->cmd.chanlist_len * sizeof(int)); if (IS_ERR(async->cmd.chanlist)) { ret = PTR_ERR(async->cmd.chanlist); + async->cmd.chanlist = NULL; DPRINTK("memdup_user failed with code %d\n", ret); goto cleanup; } @@ -1547,6 +1548,7 @@ static int do_cmdtest_ioctl(struct comedi_device *dev, cmd.chanlist_len * sizeof(int)); if (IS_ERR(chanlist)) { ret = PTR_ERR(chanlist); + chanlist = NULL; DPRINTK("memdup_user exited with code %d", ret); goto cleanup; }