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authorAndrea Parri (Microsoft) <parri.andrea@gmail.com>2021-04-20 04:43:50 +0300
committerWei Liu <wei.liu@kernel.org>2021-04-20 22:40:17 +0300
commit8c2d5e0640e53c14b6240e9bf1e32a2226e6e6ca (patch)
treef8e4d1c4f267e9a092d17105f848fe93831ca393 /drivers/hv
parentb635ccc1ec26b9b6e2cb1495c3d9d903e0b4f95a (diff)
downloadlinux-8c2d5e0640e53c14b6240e9bf1e32a2226e6e6ca.tar.xz
Drivers: hv: vmbus: Initialize unload_event statically
If a malicious or compromised Hyper-V sends a spurious message of type CHANNELMSG_UNLOAD_RESPONSE, the function vmbus_unload_response() will call complete() on an uninitialized event, and cause an oops. Reported-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20210420014350.2002-1-parri.andrea@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
Diffstat (limited to 'drivers/hv')
-rw-r--r--drivers/hv/channel_mgmt.c7
-rw-r--r--drivers/hv/connection.c2
2 files changed, 8 insertions, 1 deletions
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 4c9e45d1f462..335a10ee03a5 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -826,6 +826,11 @@ static void vmbus_unload_response(struct vmbus_channel_message_header *hdr)
/*
* This is a global event; just wakeup the waiting thread.
* Once we successfully unload, we can cleanup the monitor state.
+ *
+ * NB. A malicious or compromised Hyper-V could send a spurious
+ * message of type CHANNELMSG_UNLOAD_RESPONSE, and trigger a call
+ * of the complete() below. Make sure that unload_event has been
+ * initialized by the time this complete() is executed.
*/
complete(&vmbus_connection.unload_event);
}
@@ -841,7 +846,7 @@ void vmbus_initiate_unload(bool crash)
if (vmbus_proto_version < VERSION_WIN8_1)
return;
- init_completion(&vmbus_connection.unload_event);
+ reinit_completion(&vmbus_connection.unload_event);
memset(&hdr, 0, sizeof(struct vmbus_channel_message_header));
hdr.msgtype = CHANNELMSG_UNLOAD;
vmbus_post_msg(&hdr, sizeof(struct vmbus_channel_message_header),
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index dc19d5ae4373..311cd005b3be 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -26,6 +26,8 @@
struct vmbus_connection vmbus_connection = {
.conn_state = DISCONNECTED,
+ .unload_event = COMPLETION_INITIALIZER(
+ vmbus_connection.unload_event),
.next_gpadl_handle = ATOMIC_INIT(0xE1E10),
.ready_for_suspend_event = COMPLETION_INITIALIZER(