Fixes use-after-free bug which occurs when I disconnect my DVB-S
received while VDR is running.
Signed-off-by: Max Kellermann <max@xxxxxxxxxxx>
---
drivers/media/dvb-core/dvb_ca_en50221.c | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)
diff --git a/drivers/media/dvb-core/dvb_ca_en50221.c b/drivers/media/dvb-core/dvb_ca_en50221.c
index e33364c..dfc686a 100644
--- a/drivers/media/dvb-core/dvb_ca_en50221.c
+++ b/drivers/media/dvb-core/dvb_ca_en50221.c
@@ -148,6 +148,9 @@ struct dvb_ca_private {
/* Flag indicating if the CA device is open */
unsigned int open:1;
+ /* Flag indicating if the CA device is released */
+ unsigned int released:1;
+
/* Flag indicating the thread should wake up now */
unsigned int wakeup:1;
@@ -1392,6 +1395,11 @@ static int dvb_ca_en50221_io_read_condition(struct dvb_ca_private *ca,
int found = 0;
u8 hdr[2];
+ if (ca->released) {
+ *result = -ENODEV;
+ return 1;
+ }
+
slot = ca->next_read_slot;
while ((slot_count < ca->slot_count) && (!found)) {
if (ca->slot_info[slot].slot_state != DVB_CA_SLOTSTATE_RUNNING)
@@ -1595,6 +1603,9 @@ static int dvb_ca_en50221_io_release(struct inode *inode, struct file *file)
err = dvb_generic_release(inode, file);
+ if (ca->released)
+ dvb_ca_private_free(ca);
+
module_put(ca->pub->owner);
return err;
@@ -1701,6 +1712,7 @@ int dvb_ca_en50221_init(struct dvb_adapter *dvb_adapter,
}
init_waitqueue_head(&ca->wait_queue);
ca->open = 0;
+ ca->released = 0;
ca->wakeup = 0;
ca->next_read_slot = 0;
pubca->private = ca;
@@ -1765,12 +1777,21 @@ void dvb_ca_en50221_release(struct dvb_ca_en50221 *pubca)
dprintk("%s\n", __func__);
+ BUG_ON(ca->released);
+
/* shutdown the thread if there was one */
kthread_stop(ca->thread);
for (i = 0; i < ca->slot_count; i++) {
dvb_ca_en50221_slot_shutdown(ca, i);
}
- dvb_ca_private_free(ca);
+
+ if (ca->open) {
+ ca->released = 1;
+ mb();
+ wake_up_interruptible(&ca->wait_queue);
+ } else
+ dvb_ca_private_free(ca);
+
pubca->private = NULL;
}
--
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