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authorSean Young <sean@mess.org>2018-07-28 05:11:15 -0400
committerMauro Carvalho Chehab <mchehab+samsung@kernel.org>2018-07-30 08:19:53 -0400
commitf5dbee6e3881b1dbfdcc36008d48bd29549ab2f4 (patch)
tree0c40f47cfe5fd713d664009851b11b0439f094ad
parent92cab799bbc6fa1fca84bd1692285a5f926c17e9 (diff)
media: rc: read out of bounds if bpf reports high protocol number
The repeat period is read from a static array. If a keydown event is reported from bpf with a high protocol number, we read out of bounds. This is unlikely to end up with a reasonable repeat period at the best of times, in which case no timely key up event is generated. Signed-off-by: Sean Young <sean@mess.org> Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
-rw-r--r--drivers/media/rc/rc-main.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/drivers/media/rc/rc-main.c b/drivers/media/rc/rc-main.c
index 2e222d9ee01f..ca68e1d2b2f9 100644
--- a/drivers/media/rc/rc-main.c
+++ b/drivers/media/rc/rc-main.c
@@ -679,6 +679,14 @@ static void ir_timer_repeat(struct timer_list *t)
spin_unlock_irqrestore(&dev->keylock, flags);
}
+static unsigned int repeat_period(int protocol)
+{
+ if (protocol >= ARRAY_SIZE(protocols))
+ return 100;
+
+ return protocols[protocol].repeat_period;
+}
+
/**
* rc_repeat() - signals that a key is still pressed
* @dev: the struct rc_dev descriptor of the device
@@ -691,7 +699,7 @@ void rc_repeat(struct rc_dev *dev)
{
unsigned long flags;
unsigned int timeout = nsecs_to_jiffies(dev->timeout) +
- msecs_to_jiffies(protocols[dev->last_protocol].repeat_period);
+ msecs_to_jiffies(repeat_period(dev->last_protocol));
struct lirc_scancode sc = {
.scancode = dev->last_scancode, .rc_proto = dev->last_protocol,
.keycode = dev->keypressed ? dev->last_keycode : KEY_RESERVED,
@@ -803,7 +811,7 @@ void rc_keydown(struct rc_dev *dev, enum rc_proto protocol, u32 scancode,
if (dev->keypressed) {
dev->keyup_jiffies = jiffies + nsecs_to_jiffies(dev->timeout) +
- msecs_to_jiffies(protocols[protocol].repeat_period);
+ msecs_to_jiffies(repeat_period(protocol));
mod_timer(&dev->timer_keyup, dev->keyup_jiffies);
}
spin_unlock_irqrestore(&dev->keylock, flags);

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