V4L/DVB: ir-core: Fix null dereferences in the protocols sysfs interface

For some cards, ir_dev->props and ir_dev->raw are both NULL. These cards are
using built-in IR decoding instead of raw, and can't easily be made to switch
protocols.

So upon reading /sys/class/rc/rc?/protocols on such a card, return 'builtin' as
the supported and enabled protocol. Return -EINVAL on any attempts to change
the protocol. And most important of all, don't crash.

Signed-off-by: Brian Rogers <brian@xyzw.org>
Acked-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/media/IR/ir-sysfs.c b/drivers/media/IR/ir-sysfs.c
index 96dafc4..46d4246 100644 (file)
--- a/drivers/media/IR/ir-sysfs.c
+++ b/drivers/media/IR/ir-sysfs.c
@@ -67,13 +67,14 @@ static ssize_t show_protocols(struct device *d,
        char *tmp = buf;
        int i;
 
-       if (ir_dev->props->driver_type == RC_DRIVER_SCANCODE) {
+       if (ir_dev->props && ir_dev->props->driver_type == RC_DRIVER_SCANCODE) {
                enabled = ir_dev->rc_tab.ir_type;
                allowed = ir_dev->props->allowed_protos;
-       } else {
+       } else if (ir_dev->raw) {
                enabled = ir_dev->raw->enabled_protocols;
                allowed = ir_raw_get_allowed_protocols();
-       }
+       } else
+               return sprintf(tmp, "[builtin]\n");
 
        IR_dprintk(1, "allowed - 0x%llx, enabled - 0x%llx\n",
                   (long long)allowed,
@@ -121,10 +122,14 @@ static ssize_t store_protocols(struct device *d,
        int rc, i, count = 0;
        unsigned long flags;
 
-       if (ir_dev->props->driver_type == RC_DRIVER_SCANCODE)
+       if (ir_dev->props && ir_dev->props->driver_type == RC_DRIVER_SCANCODE)
                type = ir_dev->rc_tab.ir_type;
-       else
+       else if (ir_dev->raw)
                type = ir_dev->raw->enabled_protocols;
+       else {
+               IR_dprintk(1, "Protocol switching not supported\n");
+               return -EINVAL;
+       }
 
        while ((tmp = strsep((char **) &data, " \n")) != NULL) {
                if (!*tmp)
@@ -185,7 +190,7 @@ static ssize_t store_protocols(struct device *d,
                }
        }
 
-       if (ir_dev->props->driver_type == RC_DRIVER_SCANCODE) {
+       if (ir_dev->props && ir_dev->props->driver_type == RC_DRIVER_SCANCODE) {
                spin_lock_irqsave(&ir_dev->rc_tab.lock, flags);
                ir_dev->rc_tab.ir_type = type;
                spin_unlock_irqrestore(&ir_dev->rc_tab.lock, flags);