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| author | Andrea Parri (Microsoft) <parri.andrea@gmail.com> | 2021-04-20 03:43:50 +0200 |
|---|---|---|
| committer | Wei Liu <wei.liu@kernel.org> | 2021-04-20 19:40:17 +0000 |
| commit | 8c2d5e0640e53c14b6240e9bf1e32a2226e6e6ca (patch) | |
| tree | f8e4d1c4f267e9a092d17105f848fe93831ca393 /drivers | |
| parent | b635ccc1ec26b9b6e2cb1495c3d9d903e0b4f95a (diff) | |
| download | lwn-8c2d5e0640e53c14b6240e9bf1e32a2226e6e6ca.tar.gz lwn-8c2d5e0640e53c14b6240e9bf1e32a2226e6e6ca.zip | |
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')
| -rw-r--r-- | drivers/hv/channel_mgmt.c | 7 | ||||
| -rw-r--r-- | drivers/hv/connection.c | 2 |
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( |