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authorAndrea Parri (Microsoft) <parri.andrea@gmail.com>2021-02-01 15:48:12 +0100
committerWei Liu <wei.liu@kernel.org>2021-02-11 08:47:05 +0000
commit21a4e356d3588806307555c149b80cec3dedb180 (patch)
treec4ad61b4490f41e466122fb109c9fcb5642b24a4
parenta6c76bb08dc7f7ff2b1c381002eb6c7211746182 (diff)
downloadlinux-21a4e356d3588806307555c149b80cec3dedb180.tar.bz2
Drivers: hv: vmbus: Restrict vmbus_devices on isolated guests
Only the VSCs or ICs that have been hardened and that are critical for the successful adoption of Confidential VMs should be allowed if the guest is running isolated. This change reduces the footprint of the code that will be exercised by Confidential VMs and hence the exposure to bugs and vulnerabilities. Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20210201144814.2701-3-parri.andrea@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
-rw-r--r--drivers/hv/channel_mgmt.c38
-rw-r--r--include/linux/hyperv.h1
2 files changed, 39 insertions, 0 deletions
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 68950a1e4b63..f0ed730e2e4e 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -31,101 +31,118 @@ const struct vmbus_device vmbus_devs[] = {
{ .dev_type = HV_IDE,
HV_IDE_GUID,
.perf_device = true,
+ .allowed_in_isolated = false,
},
/* SCSI */
{ .dev_type = HV_SCSI,
HV_SCSI_GUID,
.perf_device = true,
+ .allowed_in_isolated = true,
},
/* Fibre Channel */
{ .dev_type = HV_FC,
HV_SYNTHFC_GUID,
.perf_device = true,
+ .allowed_in_isolated = false,
},
/* Synthetic NIC */
{ .dev_type = HV_NIC,
HV_NIC_GUID,
.perf_device = true,
+ .allowed_in_isolated = true,
},
/* Network Direct */
{ .dev_type = HV_ND,
HV_ND_GUID,
.perf_device = true,
+ .allowed_in_isolated = false,
},
/* PCIE */
{ .dev_type = HV_PCIE,
HV_PCIE_GUID,
.perf_device = false,
+ .allowed_in_isolated = false,
},
/* Synthetic Frame Buffer */
{ .dev_type = HV_FB,
HV_SYNTHVID_GUID,
.perf_device = false,
+ .allowed_in_isolated = false,
},
/* Synthetic Keyboard */
{ .dev_type = HV_KBD,
HV_KBD_GUID,
.perf_device = false,
+ .allowed_in_isolated = false,
},
/* Synthetic MOUSE */
{ .dev_type = HV_MOUSE,
HV_MOUSE_GUID,
.perf_device = false,
+ .allowed_in_isolated = false,
},
/* KVP */
{ .dev_type = HV_KVP,
HV_KVP_GUID,
.perf_device = false,
+ .allowed_in_isolated = false,
},
/* Time Synch */
{ .dev_type = HV_TS,
HV_TS_GUID,
.perf_device = false,
+ .allowed_in_isolated = true,
},
/* Heartbeat */
{ .dev_type = HV_HB,
HV_HEART_BEAT_GUID,
.perf_device = false,
+ .allowed_in_isolated = true,
},
/* Shutdown */
{ .dev_type = HV_SHUTDOWN,
HV_SHUTDOWN_GUID,
.perf_device = false,
+ .allowed_in_isolated = true,
},
/* File copy */
{ .dev_type = HV_FCOPY,
HV_FCOPY_GUID,
.perf_device = false,
+ .allowed_in_isolated = false,
},
/* Backup */
{ .dev_type = HV_BACKUP,
HV_VSS_GUID,
.perf_device = false,
+ .allowed_in_isolated = false,
},
/* Dynamic Memory */
{ .dev_type = HV_DM,
HV_DM_GUID,
.perf_device = false,
+ .allowed_in_isolated = false,
},
/* Unknown GUID */
{ .dev_type = HV_UNKNOWN,
.perf_device = false,
+ .allowed_in_isolated = false,
},
};
@@ -903,6 +920,20 @@ find_primary_channel_by_offer(const struct vmbus_channel_offer_channel *offer)
return channel;
}
+static bool vmbus_is_valid_device(const guid_t *guid)
+{
+ u16 i;
+
+ if (!hv_is_isolation_supported())
+ return true;
+
+ for (i = 0; i < ARRAY_SIZE(vmbus_devs); i++) {
+ if (guid_equal(guid, &vmbus_devs[i].guid))
+ return vmbus_devs[i].allowed_in_isolated;
+ }
+ return false;
+}
+
/*
* vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
*
@@ -917,6 +948,13 @@ static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
trace_vmbus_onoffer(offer);
+ if (!vmbus_is_valid_device(&offer->offer.if_type)) {
+ pr_err_ratelimited("Invalid offer %d from the host supporting isolation\n",
+ offer->child_relid);
+ atomic_dec(&vmbus_connection.offer_in_progress);
+ return;
+ }
+
oldchannel = find_primary_channel_by_offer(offer);
if (oldchannel != NULL) {
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index f0d48a368f13..e3426f8c12db 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -789,6 +789,7 @@ struct vmbus_device {
u16 dev_type;
guid_t guid;
bool perf_device;
+ bool allowed_in_isolated;
};
#define VMBUS_DEFAULT_MAX_PKT_SIZE 4096