diff mbox series

[RFC,12/23] x86/sgx: Move provisioning device creation out of SGX driver

Message ID 796316b4e8cd2a1593c409f1ef65dab4f0948428.1609890536.git.kai.huang@intel.com (mailing list archive)
State New, archived
Headers show
Series KVM SGX virtualization support | expand

Commit Message

Kai Huang Jan. 6, 2021, 1:56 a.m. UTC
From: Sean Christopherson <sean.j.christopherson@intel.com>

And extract sgx_set_attribute() out of sgx_ioc_enclave_provision() and
export it as symbol for KVM to use.

Provisioning key is sensitive. SGX driver only allows to create enclave
which can access provisioning key when enclave creator has permission to
open /dev/sgx_provision.  It should apply to VM as well, as provisioning
key is platform specific, thus unrestricted VM can also potentially
compromise provisioning key.

Move provisioning device creation out of sgx_drv_init() to sgx_init() as
preparation for adding SGX virtualization support, so that even SGX
driver is not enabled due to flexible launch control is not available,
SGX virtualization can still be enabled, and use it to restrict VM's
capability of being able to access provisioning key.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
 arch/x86/include/asm/sgx.h       |  3 +++
 arch/x86/kernel/cpu/sgx/driver.c | 17 ------------
 arch/x86/kernel/cpu/sgx/ioctl.c  | 16 ++----------
 arch/x86/kernel/cpu/sgx/main.c   | 44 +++++++++++++++++++++++++++++++-
 4 files changed, 48 insertions(+), 32 deletions(-)
diff mbox series

Patch

diff --git a/arch/x86/include/asm/sgx.h b/arch/x86/include/asm/sgx.h
index 0d643b985085..795d724fab87 100644
--- a/arch/x86/include/asm/sgx.h
+++ b/arch/x86/include/asm/sgx.h
@@ -4,6 +4,9 @@ 
 
 #include <linux/types.h>
 
+int sgx_set_attribute(unsigned long *allowed_attributes,
+		      unsigned int attribute_fd);
+
 #ifdef CONFIG_X86_SGX_VIRTUALIZATION
 struct sgx_pageinfo;
 
diff --git a/arch/x86/kernel/cpu/sgx/driver.c b/arch/x86/kernel/cpu/sgx/driver.c
index f2eac41bb4ff..4f3241109bda 100644
--- a/arch/x86/kernel/cpu/sgx/driver.c
+++ b/arch/x86/kernel/cpu/sgx/driver.c
@@ -133,10 +133,6 @@  static const struct file_operations sgx_encl_fops = {
 	.get_unmapped_area	= sgx_get_unmapped_area,
 };
 
-const struct file_operations sgx_provision_fops = {
-	.owner			= THIS_MODULE,
-};
-
 static struct miscdevice sgx_dev_enclave = {
 	.minor = MISC_DYNAMIC_MINOR,
 	.name = "sgx_enclave",
@@ -144,13 +140,6 @@  static struct miscdevice sgx_dev_enclave = {
 	.fops = &sgx_encl_fops,
 };
 
-static struct miscdevice sgx_dev_provision = {
-	.minor = MISC_DYNAMIC_MINOR,
-	.name = "sgx_provision",
-	.nodename = "sgx_provision",
-	.fops = &sgx_provision_fops,
-};
-
 int __init sgx_drv_init(void)
 {
 	unsigned int eax, ebx, ecx, edx;
@@ -184,11 +173,5 @@  int __init sgx_drv_init(void)
 	if (ret)
 		return ret;
 
-	ret = misc_register(&sgx_dev_provision);
-	if (ret) {
-		misc_deregister(&sgx_dev_enclave);
-		return ret;
-	}
-
 	return 0;
 }
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index 1bae754268d1..4714de12422d 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -2,6 +2,7 @@ 
 /*  Copyright(c) 2016-20 Intel Corporation. */
 
 #include <asm/mman.h>
+#include <asm/sgx.h>
 #include <linux/mman.h>
 #include <linux/delay.h>
 #include <linux/file.h>
@@ -664,24 +665,11 @@  static long sgx_ioc_enclave_init(struct sgx_encl *encl, void __user *arg)
 static long sgx_ioc_enclave_provision(struct sgx_encl *encl, void __user *arg)
 {
 	struct sgx_enclave_provision params;
-	struct file *file;
 
 	if (copy_from_user(&params, arg, sizeof(params)))
 		return -EFAULT;
 
-	file = fget(params.fd);
-	if (!file)
-		return -EINVAL;
-
-	if (file->f_op != &sgx_provision_fops) {
-		fput(file);
-		return -EINVAL;
-	}
-
-	encl->attributes_mask |= SGX_ATTR_PROVISIONKEY;
-
-	fput(file);
-	return 0;
+	return sgx_set_attribute(&encl->attributes_mask, params.fd);
 }
 
 long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index fd77b5775bc4..90659937950b 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -1,15 +1,18 @@ 
 // SPDX-License-Identifier: GPL-2.0
 /*  Copyright(c) 2016-20 Intel Corporation. */
 
+#include <linux/file.h>
 #include <linux/freezer.h>
 #include <linux/highmem.h>
 #include <linux/kthread.h>
+#include <linux/miscdevice.h>
 #include <linux/pagemap.h>
 #include <linux/ratelimit.h>
 #include <linux/sched/mm.h>
 #include <linux/sched/signal.h>
 #include <linux/slab.h>
 #include <asm/sgx_arch.h>
+#include <asm/sgx.h>
 #include "driver.h"
 #include "encl.h"
 #include "encls.h"
@@ -722,6 +725,38 @@  void sgx_update_lepubkeyhash(u64 *lepubkeyhash)
 		wrmsrl(MSR_IA32_SGXLEPUBKEYHASH0 + i, lepubkeyhash[i]);
 }
 
+const struct file_operations sgx_provision_fops = {
+	.owner			= THIS_MODULE,
+};
+
+static struct miscdevice sgx_dev_provision = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "sgx_provision",
+	.nodename = "sgx_provision",
+	.fops = &sgx_provision_fops,
+};
+
+int sgx_set_attribute(unsigned long *allowed_attributes,
+		      unsigned int attribute_fd)
+{
+	struct file *file;
+
+	file = fget(attribute_fd);
+	if (!file)
+		return -EINVAL;
+
+	if (file->f_op != &sgx_provision_fops) {
+		fput(file);
+		return -EINVAL;
+	}
+
+	*allowed_attributes |= SGX_ATTR_PROVISIONKEY;
+
+	fput(file);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(sgx_set_attribute);
+
 static void __init sgx_init(void)
 {
 	int ret;
@@ -736,13 +771,20 @@  static void __init sgx_init(void)
 	if (!sgx_page_reclaimer_init())
 		goto err_page_cache;
 
+	ret = misc_register(&sgx_dev_provision);
+	if (ret)
+		goto err_kthread;
+
 	/* Success if the native *or* virtual EPC driver initialized cleanly. */
 	ret = !!sgx_drv_init() & !!sgx_virt_epc_init();
 	if (ret)
-		goto err_kthread;
+		goto err_provision;
 
 	return;
 
+err_provision:
+	misc_deregister(&sgx_dev_provision);
+
 err_kthread:
 	kthread_stop(ksgxd_tsk);