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Subject[PATCH v2 14/15] [media] lirc_dev: fix potential segfault
Date
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>
---
drivers/media/rc/lirc_dev.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/media/rc/lirc_dev.c b/drivers/media/rc/lirc_dev.c
index 4b3efcf..634779a 100644
--- a/drivers/media/rc/lirc_dev.c
+++ b/drivers/media/rc/lirc_dev.c
@@ -413,7 +413,10 @@ 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 {
@@ -471,7 +474,8 @@ 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);
@@ -512,7 +516,8 @@ 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);
--
2.8.1
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