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[media] lirc_dev: fix potential segfault 

When opening or closing a lirc character device, the framework
provides to the user the possibility to keep track of opening or
closing of the device by calling two functions:

 - set_use_inc() when opening the device
 - set_use_dec() when closing the device

if those are not set by the lirc user, the system segfaults.
Check the pointer value before calling the above functions.

Signed-off-by: Andi Shyti <andi.shyti@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This commit is contained in:
Andi Shyti 2016-07-06 06:01:26 -03:00 committed by Mauro Carvalho Chehab
parent 62e92682c0
commit 8e5fa4c67d
1 changed files with 8 additions and 3 deletions
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11
drivers/media/rc/lirc_dev.c
View File

@ -411,7 +411,10 @@ int lirc_unregister_driver(int minor)
ir->d.name, ir->d.minor);
wake_up_interruptible(&ir->buf->wait_poll);
mutex_lock(&ir->irctl_lock);
ir->d.set_use_dec(ir->d.data);
if (ir->d.set_use_dec)
ir->d.set_use_dec(ir->d.data);
module_put(cdev->owner);
mutex_unlock(&ir->irctl_lock);
} else {
@ -469,7 +472,8 @@ int lirc_dev_fop_open(struct inode *inode, struct file *file)
cdev = ir->cdev;
if (try_module_get(cdev->owner)) {
ir->open++;
retval = ir->d.set_use_inc(ir->d.data);
if (ir->d.set_use_inc)
retval = ir->d.set_use_inc(ir->d.data);
if (retval) {
module_put(cdev->owner);
@ -510,7 +514,8 @@ int lirc_dev_fop_close(struct inode *inode, struct file *file)
ir->open--;
if (ir->attached) {
ir->d.set_use_dec(ir->d.data);
if (ir->d.set_use_dec)
ir->d.set_use_dec(ir->d.data);
module_put(cdev->owner);
} else {
lirc_irctl_cleanup(ir);