From e4d221b42354b2e2ddb9187a806afb651eee2cda Mon Sep 17 00:00:00 2001 From: "Andrea Parri (Microsoft)" Date: Wed, 9 Dec 2020 08:08:26 +0100 Subject: Drivers: hv: vmbus: Resolve race condition in vmbus_onoffer_rescind() An erroneous or malicious host could send multiple rescind messages for a same channel. In vmbus_onoffer_rescind(), the guest maps the channel ID to obtain a pointer to the channel object and it eventually releases such object and associated data. The host could time rescind messages and lead to an use-after-free. Add a new flag to the channel structure to make sure that only one instance of vmbus_onoffer_rescind() can get the reference to the channel object. Reported-by: Juan Vazquez Signed-off-by: Andrea Parri (Microsoft) Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20201209070827.29335-6-parri.andrea@gmail.com Signed-off-by: Wei Liu --- include/linux/hyperv.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/hyperv.h') diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index 2ea967bc17ad..f0d48a368f13 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -809,6 +809,7 @@ struct vmbus_channel { u8 monitor_bit; bool rescind; /* got rescind msg */ + bool rescind_ref; /* got rescind msg, got channel reference */ struct completion rescind_event; u32 ringbuffer_gpadlhandle; -- cgit