b43legacy: fix use-after-free rfkill bug

Fix rfkill code which caused a use-after-free bug. Thanks to David
Woodhouse for spotting this out.

Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Stefano Brivio <stefano.brivio@polimi.it>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/b43legacy/rfkill.c b/drivers/net/wireless/b43legacy/rfkill.c
index 520910f..d178dfb 100644 (file)
--- a/drivers/net/wireless/b43legacy/rfkill.c
+++ b/drivers/net/wireless/b43legacy/rfkill.c
@@ -141,8 +141,11 @@ void b43legacy_rfkill_init(struct b43legacy_wldev *dev)
        rfk->rfkill->user_claim_unsupported = 1;
 
        rfk->poll_dev = input_allocate_polled_device();
-       if (!rfk->poll_dev)
-               goto err_free_rfk;
+       if (!rfk->poll_dev) {
+               rfkill_free(rfk->rfkill);
+               goto err_freed_rfk;
+       }
+
        rfk->poll_dev->private = dev;
        rfk->poll_dev->poll = b43legacy_rfkill_poll;
        rfk->poll_dev->poll_interval = 1000; /* msecs */
@@ -178,8 +181,7 @@ err_unreg_rfk:
 err_free_polldev:
        input_free_polled_device(rfk->poll_dev);
        rfk->poll_dev = NULL;
-err_free_rfk:
-       rfkill_free(rfk->rfkill);
+err_freed_rfk:
        rfk->rfkill = NULL;
 out_error:
        rfk->registered = 0;
@@ -198,7 +200,6 @@ void b43legacy_rfkill_exit(struct b43legacy_wldev *dev)
        rfkill_unregister(rfk->rfkill);
        input_free_polled_device(rfk->poll_dev);
        rfk->poll_dev = NULL;
-       rfkill_free(rfk->rfkill);
        rfk->rfkill = NULL;
 }