From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Juergen Gross <jgross@suse.com>
Date: Thu, 9 Nov 2017 14:27:36 +0100
Subject: [PATCH] x86/virt: Add enum for hypervisors to replace x86_hyper
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CVE-2017-5754

The x86_hyper pointer is only used for checking whether a virtual
device is supporting the hypervisor the system is running on.

Use an enum for that purpose instead and drop the x86_hyper pointer.

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Xavier Deguillard <xdeguillard@vmware.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: akataria@vmware.com
Cc: arnd@arndb.de
Cc: boris.ostrovsky@oracle.com
Cc: devel@linuxdriverproject.org
Cc: dmitry.torokhov@gmail.com
Cc: gregkh@linuxfoundation.org
Cc: haiyangz@microsoft.com
Cc: kvm@vger.kernel.org
Cc: kys@microsoft.com
Cc: linux-graphics-maintainer@vmware.com
Cc: linux-input@vger.kernel.org
Cc: moltmann@vmware.com
Cc: pbonzini@redhat.com
Cc: pv-drivers@vmware.com
Cc: rkrcmar@redhat.com
Cc: sthemmin@microsoft.com
Cc: virtualization@lists.linux-foundation.org
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/20171109132739.23465-3-jgross@suse.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
(backported from commit 03b2a320b19f1424e9ac9c21696be9c60b6d0d93)
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
(cherry picked from commit c24b0a226fadfe1abe78fa568ff84fea6ecd7ca5)
Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
---
 arch/x86/include/asm/hypervisor.h | 23 ++++++++++++++---------
 arch/x86/hyperv/hv_init.c         |  2 +-
 arch/x86/kernel/cpu/hypervisor.c  | 12 +++++++++---
 arch/x86/kernel/cpu/mshyperv.c    |  6 +++---
 arch/x86/kernel/cpu/vmware.c      |  4 ++--
 arch/x86/kernel/kvm.c             |  4 ++--
 arch/x86/xen/enlighten_hvm.c      |  4 ++--
 arch/x86/xen/enlighten_pv.c       |  4 ++--
 drivers/hv/vmbus_drv.c            |  2 +-
 drivers/input/mouse/vmmouse.c     | 10 ++++------
 drivers/misc/vmw_balloon.c        |  2 +-
 11 files changed, 41 insertions(+), 32 deletions(-)

diff --git a/arch/x86/include/asm/hypervisor.h b/arch/x86/include/asm/hypervisor.h
index 0eca7239a7aa..1b0a5abcd8ae 100644
--- a/arch/x86/include/asm/hypervisor.h
+++ b/arch/x86/include/asm/hypervisor.h
@@ -29,6 +29,16 @@
 /*
  * x86 hypervisor information
  */
+
+enum x86_hypervisor_type {
+	X86_HYPER_NATIVE = 0,
+	X86_HYPER_VMWARE,
+	X86_HYPER_MS_HYPERV,
+	X86_HYPER_XEN_PV,
+	X86_HYPER_XEN_HVM,
+	X86_HYPER_KVM,
+};
+
 struct hypervisor_x86 {
 	/* Hypervisor name */
 	const char	*name;
@@ -36,6 +46,9 @@ struct hypervisor_x86 {
 	/* Detection routine */
 	uint32_t	(*detect)(void);
 
+	/* Hypervisor type */
+	enum x86_hypervisor_type type;
+
 	/* init time callbacks */
 	struct x86_hyper_init init;
 
@@ -43,15 +56,7 @@ struct hypervisor_x86 {
 	struct x86_hyper_runtime runtime;
 };
 
-extern const struct hypervisor_x86 *x86_hyper;
-
-/* Recognized hypervisors */
-extern const struct hypervisor_x86 x86_hyper_vmware;
-extern const struct hypervisor_x86 x86_hyper_ms_hyperv;
-extern const struct hypervisor_x86 x86_hyper_xen_pv;
-extern const struct hypervisor_x86 x86_hyper_xen_hvm;
-extern const struct hypervisor_x86 x86_hyper_kvm;
-
+extern enum x86_hypervisor_type x86_hyper_type;
 extern void init_hypervisor_platform(void);
 #else
 static inline void init_hypervisor_platform(void) { }
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index ec7c9661743f..32fa894139d5 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -99,7 +99,7 @@ void hyperv_init(void)
 	u64 guest_id;
 	union hv_x64_msr_hypercall_contents hypercall_msr;
 
-	if (x86_hyper != &x86_hyper_ms_hyperv)
+	if (x86_hyper_type != X86_HYPER_MS_HYPERV)
 		return;
 
 	/*
diff --git a/arch/x86/kernel/cpu/hypervisor.c b/arch/x86/kernel/cpu/hypervisor.c
index 22226c1bf092..bea8d3e24f50 100644
--- a/arch/x86/kernel/cpu/hypervisor.c
+++ b/arch/x86/kernel/cpu/hypervisor.c
@@ -26,6 +26,12 @@
 #include <asm/processor.h>
 #include <asm/hypervisor.h>
 
+extern const struct hypervisor_x86 x86_hyper_vmware;
+extern const struct hypervisor_x86 x86_hyper_ms_hyperv;
+extern const struct hypervisor_x86 x86_hyper_xen_pv;
+extern const struct hypervisor_x86 x86_hyper_xen_hvm;
+extern const struct hypervisor_x86 x86_hyper_kvm;
+
 static const __initconst struct hypervisor_x86 * const hypervisors[] =
 {
 #ifdef CONFIG_XEN_PV
@@ -41,8 +47,8 @@ static const __initconst struct hypervisor_x86 * const hypervisors[] =
 #endif
 };
 
-const struct hypervisor_x86 *x86_hyper;
-EXPORT_SYMBOL(x86_hyper);
+enum x86_hypervisor_type x86_hyper_type;
+EXPORT_SYMBOL(x86_hyper_type);
 
 static inline const struct hypervisor_x86 * __init
 detect_hypervisor_vendor(void)
@@ -87,6 +93,6 @@ void __init init_hypervisor_platform(void)
 	copy_array(&h->init, &x86_init.hyper, sizeof(h->init));
 	copy_array(&h->runtime, &x86_platform.hyper, sizeof(h->runtime));
 
-	x86_hyper = h;
+	x86_hyper_type = h->type;
 	x86_init.hyper.init_platform();
 }
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 9707e431da27..3672f1192119 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -252,9 +252,9 @@ static void __init ms_hyperv_init_platform(void)
 #endif
 }
 
-const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
-	.name			= "Microsoft HyperV",
+const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
+	.name			= "Microsoft Hyper-V",
 	.detect			= ms_hyperv_platform,
+	.type			= X86_HYPER_MS_HYPERV,
 	.init.init_platform	= ms_hyperv_init_platform,
 };
-EXPORT_SYMBOL(x86_hyper_ms_hyperv);
diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index 4804c1d063c8..8e005329648b 100644
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -205,10 +205,10 @@ static bool __init vmware_legacy_x2apic_available(void)
 	       (eax & (1 << VMWARE_PORT_CMD_LEGACY_X2APIC)) != 0;
 }
 
-const __refconst struct hypervisor_x86 x86_hyper_vmware = {
+const __initconst struct hypervisor_x86 x86_hyper_vmware = {
 	.name			= "VMware",
 	.detect			= vmware_platform,
+	.type			= X86_HYPER_VMWARE,
 	.init.init_platform	= vmware_platform_setup,
 	.init.x2apic_available	= vmware_legacy_x2apic_available,
 };
-EXPORT_SYMBOL(x86_hyper_vmware);
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 54e373bfeab9..b65a51a24647 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -544,12 +544,12 @@ static uint32_t __init kvm_detect(void)
 	return kvm_cpuid_base();
 }
 
-const struct hypervisor_x86 x86_hyper_kvm __refconst = {
+const __initconst struct hypervisor_x86 x86_hyper_kvm = {
 	.name			= "KVM",
 	.detect			= kvm_detect,
+	.type			= X86_HYPER_KVM,
 	.init.x2apic_available	= kvm_para_available,
 };
-EXPORT_SYMBOL_GPL(x86_hyper_kvm);
 
 static __init int activate_jump_labels(void)
 {
diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index 7b1622089f96..754d5391d9fa 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -226,12 +226,12 @@ static uint32_t __init xen_platform_hvm(void)
 	return xen_cpuid_base();
 }
 
-const struct hypervisor_x86 x86_hyper_xen_hvm = {
+const __initconst struct hypervisor_x86 x86_hyper_xen_hvm = {
 	.name                   = "Xen HVM",
 	.detect                 = xen_platform_hvm,
+	.type			= X86_HYPER_XEN_HVM,
 	.init.init_platform     = xen_hvm_guest_init,
 	.init.x2apic_available  = xen_x2apic_para_available,
 	.init.init_mem_mapping	= xen_hvm_init_mem_mapping,
 	.runtime.pin_vcpu       = xen_pin_vcpu,
 };
-EXPORT_SYMBOL(x86_hyper_xen_hvm);
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 4110fc9e5ee9..63c81154083b 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -1458,9 +1458,9 @@ static uint32_t __init xen_platform_pv(void)
 	return 0;
 }
 
-const struct hypervisor_x86 x86_hyper_xen_pv = {
+const __initconst struct hypervisor_x86 x86_hyper_xen_pv = {
 	.name                   = "Xen PV",
 	.detect                 = xen_platform_pv,
+	.type			= X86_HYPER_XEN_PV,
 	.runtime.pin_vcpu       = xen_pin_vcpu,
 };
-EXPORT_SYMBOL(x86_hyper_xen_pv);
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 5ad627044dd1..8aca7613e482 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1551,7 +1551,7 @@ static int __init hv_acpi_init(void)
 {
 	int ret, t;
 
-	if (x86_hyper != &x86_hyper_ms_hyperv)
+	if (x86_hyper_type != X86_HYPER_MS_HYPERV)
 		return -ENODEV;
 
 	init_completion(&probe_event);
diff --git a/drivers/input/mouse/vmmouse.c b/drivers/input/mouse/vmmouse.c
index 0f586780ceb4..1ae5c1ef3f5b 100644
--- a/drivers/input/mouse/vmmouse.c
+++ b/drivers/input/mouse/vmmouse.c
@@ -316,11 +316,9 @@ static int vmmouse_enable(struct psmouse *psmouse)
 /*
  * Array of supported hypervisors.
  */
-static const struct hypervisor_x86 *vmmouse_supported_hypervisors[] = {
-	&x86_hyper_vmware,
-#ifdef CONFIG_KVM_GUEST
-	&x86_hyper_kvm,
-#endif
+static enum x86_hypervisor_type vmmouse_supported_hypervisors[] = {
+	X86_HYPER_VMWARE,
+	X86_HYPER_KVM,
 };
 
 /**
@@ -331,7 +329,7 @@ static bool vmmouse_check_hypervisor(void)
 	int i;
 
 	for (i = 0; i < ARRAY_SIZE(vmmouse_supported_hypervisors); i++)
-		if (vmmouse_supported_hypervisors[i] == x86_hyper)
+		if (vmmouse_supported_hypervisors[i] == x86_hyper_type)
 			return true;
 
 	return false;
diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
index 1e688bfec567..9047c0a529b2 100644
--- a/drivers/misc/vmw_balloon.c
+++ b/drivers/misc/vmw_balloon.c
@@ -1271,7 +1271,7 @@ static int __init vmballoon_init(void)
 	 * Check if we are running on VMware's hypervisor and bail out
 	 * if we are not.
 	 */
-	if (x86_hyper != &x86_hyper_vmware)
+	if (x86_hyper_type != X86_HYPER_VMWARE)
 		return -ENODEV;
 
 	for (is_2m_pages = 0; is_2m_pages < VMW_BALLOON_NUM_PAGE_SIZES;
-- 
2.14.2

