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Message-ID: <173a196e-fa6b-23b8-c818-dfca6cdadcc6@tycho.nsa.gov>
Date: Wed, 30 Oct 2019 09:45:05 -0400
From: Stephen Smalley <sds@...ho.nsa.gov>
To: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
linux-kernel@...r.kernel.org, x86@...nel.org,
linux-sgx@...r.kernel.org
Cc: akpm@...ux-foundation.org, dave.hansen@...el.com,
sean.j.christopherson@...el.com, nhorman@...hat.com,
npmccallum@...hat.com, serge.ayoun@...el.com,
shay.katz-zamir@...el.com, haitao.huang@...el.com,
andriy.shevchenko@...ux.intel.com, tglx@...utronix.de,
kai.svahn@...el.com, bp@...en8.de, josh@...htriplett.org,
luto@...nel.org, kai.huang@...el.com, rientjes@...gle.com,
cedric.xing@...el.com, puiterwijk@...hat.com,
linux-security-module@...r.kernel.org,
Suresh Siddha <suresh.b.siddha@...el.com>
Subject: Re: [PATCH v23 12/24] x86/sgx: Linux Enclave Driver
On 10/28/19 5:03 PM, Jarkko Sakkinen wrote:
> Intel Software Guard eXtensions (SGX) is a set of CPU instructions that
> can be used by applications to set aside private regions of code and
> data. The code outside the SGX hosted software entity is disallowed to
> access the memory inside the enclave enforced by the CPU. We call these
> entities as enclaves.
>
> This commit implements a driver that provides an ioctl API to construct
> and run enclaves. Enclaves are constructed from pages residing in
> reserved physical memory areas. The contents of these pages can only be
> accessed when they are mapped as part of an enclave, by a hardware
> thread running inside the enclave.
>
> The starting state of an enclave consists of a fixed measured set of
> pages that are copied to the EPC during the construction process by
> using ENCLS leaf functions and Software Enclave Control Structure (SECS)
> that defines the enclave properties.
>
> Enclave are constructed by using ENCLS leaf functions ECREATE, EADD and
> EINIT. ECREATE initializes SECS, EADD copies pages from system memory to
> the EPC and EINIT check a given signed measurement and moves the enclave
> into a state ready for execution.
>
> An initialized enclave can only be accessed through special Thread Control
> Structure (TCS) pages by using ENCLU (ring-3 only) leaf EENTER. This leaf
> function converts a thread into enclave mode and continues the execution in
> the offset defined by the TCS provided to EENTER. An enclave is exited
> through syscall, exception, interrupts or by explicitly calling another
> ENCLU leaf EEXIT.
>
> The permissions, which enclave page is added will set the limit for maximum
> permissions that can be set for mmap() and mprotect(). This will
> effectively allow to build different security schemes between producers and
> consumers of enclaves. Later on we can increase granularity with LSM hooks
> for page addition (i.e. for producers) and mapping of the enclave (i.e. for
> consumers)
Where do things stand wrt to ensuring that SGX cannot be used to
introduce executable mappings that were never authorized by the LSM (or
never measured by IMA)?
>
> Cc: linux-security-module@...r.kernel.org
> Co-developed-by: Sean Christopherson <sean.j.christopherson@...el.com>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
> Co-developed-by: Suresh Siddha <suresh.b.siddha@...el.com>
> Signed-off-by: Suresh Siddha <suresh.b.siddha@...el.com>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
> ---
> Documentation/ioctl/ioctl-number.rst | 1 +
> arch/x86/include/uapi/asm/sgx.h | 64 +++
> arch/x86/kernel/cpu/sgx/Makefile | 3 +
> arch/x86/kernel/cpu/sgx/driver.c | 252 ++++++++++
> arch/x86/kernel/cpu/sgx/driver.h | 32 ++
> arch/x86/kernel/cpu/sgx/encl.c | 329 ++++++++++++++
> arch/x86/kernel/cpu/sgx/encl.h | 87 ++++
> arch/x86/kernel/cpu/sgx/ioctl.c | 656 +++++++++++++++++++++++++++
> arch/x86/kernel/cpu/sgx/main.c | 10 +
> arch/x86/kernel/cpu/sgx/reclaim.c | 1 +
> 10 files changed, 1435 insertions(+)
> create mode 100644 arch/x86/include/uapi/asm/sgx.h
> create mode 100644 arch/x86/kernel/cpu/sgx/driver.c
> create mode 100644 arch/x86/kernel/cpu/sgx/driver.h
> create mode 100644 arch/x86/kernel/cpu/sgx/encl.c
> create mode 100644 arch/x86/kernel/cpu/sgx/encl.h
> create mode 100644 arch/x86/kernel/cpu/sgx/ioctl.c
>
> diff --git a/Documentation/ioctl/ioctl-number.rst b/Documentation/ioctl/ioctl-number.rst
> index bef79cd4c6b4..f9f3ea9606fc 100644
> --- a/Documentation/ioctl/ioctl-number.rst
> +++ b/Documentation/ioctl/ioctl-number.rst
> @@ -321,6 +321,7 @@ Code Seq# Include File Comments
> <mailto:tlewis@...dspring.com>
> 0xA3 90-9F linux/dtlk.h
> 0xA4 00-1F uapi/linux/tee.h Generic TEE subsystem
> +0xA4 00-1F uapi/asm/sgx.h Intel SGX subsystem (a legit conflict as TEE and SGX do not co-exist)
> 0xAA 00-3F linux/uapi/linux/userfaultfd.h
> 0xAB 00-1F linux/nbd.h
> 0xAC 00-1F linux/raw.h
> diff --git a/arch/x86/include/uapi/asm/sgx.h b/arch/x86/include/uapi/asm/sgx.h
> new file mode 100644
> index 000000000000..e0f79ebdfd8a
> --- /dev/null
> +++ b/arch/x86/include/uapi/asm/sgx.h
> @@ -0,0 +1,64 @@
> +/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) WITH Linux-syscall-note */
> +/*
> + * Copyright(c) 2016-19 Intel Corporation.
> + */
> +#ifndef _UAPI_ASM_X86_SGX_H
> +#define _UAPI_ASM_X86_SGX_H
> +
> +#include <linux/types.h>
> +#include <linux/ioctl.h>
> +
> +/**
> + * enum sgx_epage_flags - page control flags
> + * %SGX_PAGE_MEASURE: Measure the page contents with a sequence of
> + * ENCLS[EEXTEND] operations.
> + */
> +enum sgx_page_flags {
> + SGX_PAGE_MEASURE = 0x01,
> +};
> +
> +#define SGX_MAGIC 0xA4
> +
> +#define SGX_IOC_ENCLAVE_CREATE \
> + _IOW(SGX_MAGIC, 0x00, struct sgx_enclave_create)
> +#define SGX_IOC_ENCLAVE_ADD_PAGES \
> + _IOWR(SGX_MAGIC, 0x01, struct sgx_enclave_add_pages)
> +#define SGX_IOC_ENCLAVE_INIT \
> + _IOW(SGX_MAGIC, 0x02, struct sgx_enclave_init)
> +
> +/**
> + * struct sgx_enclave_create - parameter structure for the
> + * %SGX_IOC_ENCLAVE_CREATE ioctl
> + * @src: address for the SECS page data
> + */
> +struct sgx_enclave_create {
> + __u64 src;
> +};
> +
> +/**
> + * struct sgx_enclave_add_pages - parameter structure for the
> + * %SGX_IOC_ENCLAVE_ADD_PAGE ioctl
> + * @src: start address for the page data
> + * @offset: starting page offset
> + * @length: length of the data (multiple of the page size)
> + * @secinfo: address for the SECINFO data
> + * @flags: page control flags
> + */
> +struct sgx_enclave_add_pages {
> + __u64 src;
> + __u64 offset;
> + __u64 length;
> + __u64 secinfo;
> + __u64 flags;
> +};
> +
> +/**
> + * struct sgx_enclave_init - parameter structure for the
> + * %SGX_IOC_ENCLAVE_INIT ioctl
> + * @sigstruct: address for the SIGSTRUCT data
> + */
> +struct sgx_enclave_init {
> + __u64 sigstruct;
> +};
> +
> +#endif /* _UAPI_ASM_X86_SGX_H */
> diff --git a/arch/x86/kernel/cpu/sgx/Makefile b/arch/x86/kernel/cpu/sgx/Makefile
> index 874492d9e3bd..3ddcdabab081 100644
> --- a/arch/x86/kernel/cpu/sgx/Makefile
> +++ b/arch/x86/kernel/cpu/sgx/Makefile
> @@ -1,4 +1,7 @@
> obj-y += \
> + driver.o \
> + encl.o \
> encls.o \
> + ioctl.o \
> main.o \
> reclaim.o
> diff --git a/arch/x86/kernel/cpu/sgx/driver.c b/arch/x86/kernel/cpu/sgx/driver.c
> new file mode 100644
> index 000000000000..c724dcccf2e2
> --- /dev/null
> +++ b/arch/x86/kernel/cpu/sgx/driver.c
> @@ -0,0 +1,252 @@
> +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
> +// Copyright(c) 2016-18 Intel Corporation.
> +
> +#include <linux/acpi.h>
> +#include <linux/cdev.h>
> +#include <linux/mman.h>
> +#include <linux/platform_device.h>
> +#include <linux/security.h>
> +#include <linux/suspend.h>
> +#include <asm/traps.h>
> +#include "driver.h"
> +#include "encl.h"
> +
> +MODULE_DESCRIPTION("Intel SGX Enclave Driver");
> +MODULE_AUTHOR("Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>");
> +MODULE_LICENSE("Dual BSD/GPL");
> +
> +struct workqueue_struct *sgx_encl_wq;
> +u64 sgx_encl_size_max_32;
> +u64 sgx_encl_size_max_64;
> +u32 sgx_misc_reserved_mask;
> +u64 sgx_attributes_reserved_mask;
> +u64 sgx_xfrm_reserved_mask = ~0x3;
> +u32 sgx_xsave_size_tbl[64];
> +
> +static int sgx_open(struct inode *inode, struct file *file)
> +{
> + struct sgx_encl *encl;
> + int ret;
> +
> + encl = kzalloc(sizeof(*encl), GFP_KERNEL);
> + if (!encl)
> + return -ENOMEM;
> +
> + atomic_set(&encl->flags, 0);
> + kref_init(&encl->refcount);
> + INIT_RADIX_TREE(&encl->page_tree, GFP_KERNEL);
> + mutex_init(&encl->lock);
> + INIT_LIST_HEAD(&encl->mm_list);
> + spin_lock_init(&encl->mm_lock);
> +
> + ret = init_srcu_struct(&encl->srcu);
> + if (ret) {
> + kfree(encl);
> + return ret;
> + }
> +
> + file->private_data = encl;
> +
> + return 0;
> +}
> +
> +static int sgx_release(struct inode *inode, struct file *file)
> +{
> + struct sgx_encl *encl = file->private_data;
> + struct sgx_encl_mm *encl_mm;
> +
> + for ( ; ; ) {
> + spin_lock(&encl->mm_lock);
> +
> + if (list_empty(&encl->mm_list)) {
> + encl_mm = NULL;
> + } else {
> + encl_mm = list_first_entry(&encl->mm_list,
> + struct sgx_encl_mm, list);
> + list_del_rcu(&encl_mm->list);
> + }
> +
> + spin_unlock(&encl->mm_lock);
> +
> + /* The list is empty, ready to go. */
> + if (!encl_mm)
> + break;
> +
> + synchronize_srcu(&encl->srcu);
> + mmu_notifier_unregister(&encl_mm->mmu_notifier, encl_mm->mm);
> + kfree(encl_mm);
> + };
> +
> + mutex_lock(&encl->lock);
> + atomic_or(SGX_ENCL_DEAD, &encl->flags);
> + mutex_unlock(&encl->lock);
> +
> + kref_put(&encl->refcount, sgx_encl_release);
> + return 0;
> +}
> +
> +#ifdef CONFIG_COMPAT
> +static long sgx_compat_ioctl(struct file *filep, unsigned int cmd,
> + unsigned long arg)
> +{
> + return sgx_ioctl(filep, cmd, arg);
> +}
> +#endif
> +
> +static int sgx_mmap(struct file *file, struct vm_area_struct *vma)
> +{
> + struct sgx_encl *encl = file->private_data;
> + int ret;
> +
> + ret = sgx_encl_may_map(encl, vma->vm_start, vma->vm_end,
> + vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC));
> + if (ret)
> + return ret;
> +
> + ret = sgx_encl_mm_add(encl, vma->vm_mm);
> + if (ret)
> + return ret;
> +
> + vma->vm_ops = &sgx_vm_ops;
> + vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP | VM_IO;
> + vma->vm_private_data = encl;
> +
> + return 0;
> +}
> +
> +static unsigned long sgx_get_unmapped_area(struct file *file,
> + unsigned long addr,
> + unsigned long len,
> + unsigned long pgoff,
> + unsigned long flags)
> +{
> + if (flags & MAP_PRIVATE)
> + return -EINVAL;
> +
> + if (flags & MAP_FIXED)
> + return addr;
> +
> + return current->mm->get_unmapped_area(file, addr, len, pgoff, flags);
> +}
> +
> +static const struct file_operations sgx_encl_fops = {
> + .owner = THIS_MODULE,
> + .open = sgx_open,
> + .release = sgx_release,
> + .unlocked_ioctl = sgx_ioctl,
> +#ifdef CONFIG_COMPAT
> + .compat_ioctl = sgx_compat_ioctl,
> +#endif
> + .mmap = sgx_mmap,
> + .get_unmapped_area = sgx_get_unmapped_area,
> +};
> +
> +static struct bus_type sgx_bus_type = {
> + .name = "sgx",
> +};
> +
> +static struct device sgx_encl_dev;
> +static struct cdev sgx_encl_cdev;
> +static dev_t sgx_devt;
> +
> +static void sgx_dev_release(struct device *dev)
> +{
> +}
> +
> +static __init int sgx_dev_init(const char *name, struct device *dev,
> + struct cdev *cdev,
> + const struct file_operations *fops, int minor)
> +{
> + int ret;
> +
> + device_initialize(dev);
> +
> + dev->bus = &sgx_bus_type;
> + dev->devt = MKDEV(MAJOR(sgx_devt), minor);
> + dev->release = sgx_dev_release;
> +
> + ret = dev_set_name(dev, name);
> + if (ret) {
> + put_device(dev);
> + return ret;
> + }
> +
> + cdev_init(cdev, fops);
> + cdev->owner = THIS_MODULE;
> + return 0;
> +}
> +
> +int __init sgx_drv_init(void)
> +{
> + unsigned int eax, ebx, ecx, edx;
> + u64 attr_mask, xfrm_mask;
> + int ret;
> + int i;
> +
> + if (!boot_cpu_has(X86_FEATURE_SGX_LC)) {
> + pr_info("The public key MSRs are not writable\n");
> + return -ENODEV;
> + }
> +
> + ret = bus_register(&sgx_bus_type);
> + if (ret)
> + return ret;
> +
> + ret = alloc_chrdev_region(&sgx_devt, 0, SGX_DRV_NR_DEVICES, "sgx");
> + if (ret < 0)
> + goto err_bus;
> +
> + cpuid_count(SGX_CPUID, 0, &eax, &ebx, &ecx, &edx);
> + sgx_misc_reserved_mask = ~ebx | SGX_MISC_RESERVED_MASK;
> + sgx_encl_size_max_64 = 1ULL << ((edx >> 8) & 0xFF);
> + sgx_encl_size_max_32 = 1ULL << (edx & 0xFF);
> +
> + cpuid_count(SGX_CPUID, 1, &eax, &ebx, &ecx, &edx);
> +
> + attr_mask = (((u64)ebx) << 32) + (u64)eax;
> + sgx_attributes_reserved_mask = ~attr_mask | SGX_ATTR_RESERVED_MASK;
> +
> + if (boot_cpu_has(X86_FEATURE_OSXSAVE)) {
> + xfrm_mask = (((u64)edx) << 32) + (u64)ecx;
> +
> + for (i = 2; i < 64; i++) {
> + cpuid_count(0x0D, i, &eax, &ebx, &ecx, &edx);
> + if ((1 << i) & xfrm_mask)
> + sgx_xsave_size_tbl[i] = eax + ebx;
> + }
> +
> + sgx_xfrm_reserved_mask = ~xfrm_mask;
> + }
> +
> + ret = sgx_dev_init("sgx/enclave", &sgx_encl_dev, &sgx_encl_cdev,
> + &sgx_encl_fops, 0);
> + if (ret)
> + goto err_chrdev_region;
> +
> + sgx_encl_wq = alloc_workqueue("sgx-encl-wq",
> + WQ_UNBOUND | WQ_FREEZABLE, 1);
> + if (!sgx_encl_wq) {
> + ret = -ENOMEM;
> + goto err_encl_dev;
> + }
> +
> + ret = cdev_device_add(&sgx_encl_cdev, &sgx_encl_dev);
> + if (ret)
> + goto err_encl_wq;
> +
> + return 0;
> +
> +err_encl_wq:
> + destroy_workqueue(sgx_encl_wq);
> +
> +err_encl_dev:
> + put_device(&sgx_encl_dev);
> +
> +err_chrdev_region:
> + unregister_chrdev_region(sgx_devt, SGX_DRV_NR_DEVICES);
> +
> +err_bus:
> + bus_unregister(&sgx_bus_type);
> +
> + return ret;
> +}
> diff --git a/arch/x86/kernel/cpu/sgx/driver.h b/arch/x86/kernel/cpu/sgx/driver.h
> new file mode 100644
> index 000000000000..e95c6e86c0c6
> --- /dev/null
> +++ b/arch/x86/kernel/cpu/sgx/driver.h
> @@ -0,0 +1,32 @@
> +/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
> +#ifndef __ARCH_SGX_DRIVER_H__
> +#define __ARCH_SGX_DRIVER_H__
> +
> +#include <crypto/hash.h>
> +#include <linux/kref.h>
> +#include <linux/mmu_notifier.h>
> +#include <linux/radix-tree.h>
> +#include <linux/rwsem.h>
> +#include <linux/sched.h>
> +#include <linux/workqueue.h>
> +#include <uapi/asm/sgx.h>
> +#include "sgx.h"
> +
> +#define SGX_DRV_NR_DEVICES 2
> +#define SGX_EINIT_SPIN_COUNT 20
> +#define SGX_EINIT_SLEEP_COUNT 50
> +#define SGX_EINIT_SLEEP_TIME 20
> +
> +extern struct workqueue_struct *sgx_encl_wq;
> +extern u64 sgx_encl_size_max_32;
> +extern u64 sgx_encl_size_max_64;
> +extern u32 sgx_misc_reserved_mask;
> +extern u64 sgx_attributes_reserved_mask;
> +extern u64 sgx_xfrm_reserved_mask;
> +extern u32 sgx_xsave_size_tbl[64];
> +
> +long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg);
> +
> +int sgx_drv_init(void);
> +
> +#endif /* __ARCH_X86_SGX_DRIVER_H__ */
> diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
> new file mode 100644
> index 000000000000..cd2b8dbb0eca
> --- /dev/null
> +++ b/arch/x86/kernel/cpu/sgx/encl.c
> @@ -0,0 +1,329 @@
> +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
> +// Copyright(c) 2016-18 Intel Corporation.
> +
> +#include <linux/lockdep.h>
> +#include <linux/mm.h>
> +#include <linux/mman.h>
> +#include <linux/shmem_fs.h>
> +#include <linux/suspend.h>
> +#include <linux/sched/mm.h>
> +#include "arch.h"
> +#include "encl.h"
> +#include "sgx.h"
> +
> +static struct sgx_encl_page *sgx_encl_load_page(struct sgx_encl *encl,
> + unsigned long addr)
> +{
> + struct sgx_encl_page *entry;
> + unsigned int flags;
> +
> + /* If process was forked, VMA is still there but vm_private_data is set
> + * to NULL.
> + */
> + if (!encl)
> + return ERR_PTR(-EFAULT);
> +
> + flags = atomic_read(&encl->flags);
> +
> + if ((flags & SGX_ENCL_DEAD) || !(flags & SGX_ENCL_INITIALIZED))
> + return ERR_PTR(-EFAULT);
> +
> + entry = radix_tree_lookup(&encl->page_tree, addr >> PAGE_SHIFT);
> + if (!entry)
> + return ERR_PTR(-EFAULT);
> +
> + /* Page is already resident in the EPC. */
> + if (entry->epc_page)
> + return entry;
> +
> + return ERR_PTR(-EFAULT);
> +}
> +
> +static void sgx_mmu_notifier_release(struct mmu_notifier *mn,
> + struct mm_struct *mm)
> +{
> + struct sgx_encl_mm *encl_mm =
> + container_of(mn, struct sgx_encl_mm, mmu_notifier);
> + struct sgx_encl_mm *tmp = NULL;
> +
> + /*
> + * The enclave itself can remove encl_mm. Note, objects can't be moved
> + * off an RCU protected list, but deletion is ok.
> + */
> + spin_lock(&encl_mm->encl->mm_lock);
> + list_for_each_entry(tmp, &encl_mm->encl->mm_list, list) {
> + if (tmp == encl_mm) {
> + list_del_rcu(&encl_mm->list);
> + break;
> + }
> + }
> + spin_unlock(&encl_mm->encl->mm_lock);
> +
> + if (tmp == encl_mm) {
> + synchronize_srcu(&encl_mm->encl->srcu);
> + mmu_notifier_put(mn);
> + }
> +}
> +
> +static void sgx_mmu_notifier_free(struct mmu_notifier *mn)
> +{
> + struct sgx_encl_mm *encl_mm =
> + container_of(mn, struct sgx_encl_mm, mmu_notifier);
> +
> + kfree(encl_mm);
> +}
> +
> +static const struct mmu_notifier_ops sgx_mmu_notifier_ops = {
> + .release = sgx_mmu_notifier_release,
> + .free_notifier = sgx_mmu_notifier_free,
> +};
> +
> +static struct sgx_encl_mm *sgx_encl_find_mm(struct sgx_encl *encl,
> + struct mm_struct *mm)
> +{
> + struct sgx_encl_mm *encl_mm = NULL;
> + struct sgx_encl_mm *tmp;
> + int idx;
> +
> + idx = srcu_read_lock(&encl->srcu);
> +
> + list_for_each_entry_rcu(tmp, &encl->mm_list, list) {
> + if (tmp->mm == mm) {
> + encl_mm = tmp;
> + break;
> + }
> + }
> +
> + srcu_read_unlock(&encl->srcu, idx);
> +
> + return encl_mm;
> +}
> +
> +int sgx_encl_mm_add(struct sgx_encl *encl, struct mm_struct *mm)
> +{
> + struct sgx_encl_mm *encl_mm;
> + int ret;
> +
> + if (atomic_read(&encl->flags) & SGX_ENCL_DEAD)
> + return -EINVAL;
> +
> + /*
> + * mm_structs are kept on mm_list until the mm or the enclave dies,
> + * i.e. once an mm is off the list, it's gone for good, therefore it's
> + * impossible to get a false positive on @mm due to a stale mm_list.
> + */
> + if (sgx_encl_find_mm(encl, mm))
> + return 0;
> +
> + encl_mm = kzalloc(sizeof(*encl_mm), GFP_KERNEL);
> + if (!encl_mm)
> + return -ENOMEM;
> +
> + encl_mm->encl = encl;
> + encl_mm->mm = mm;
> + encl_mm->mmu_notifier.ops = &sgx_mmu_notifier_ops;
> +
> + ret = __mmu_notifier_register(&encl_mm->mmu_notifier, mm);
> + if (ret) {
> + kfree(encl_mm);
> + return ret;
> + }
> +
> + spin_lock(&encl->mm_lock);
> + list_add_rcu(&encl_mm->list, &encl->mm_list);
> + spin_unlock(&encl->mm_lock);
> +
> + synchronize_srcu(&encl->srcu);
> +
> + return 0;
> +}
> +
> +static void sgx_vma_open(struct vm_area_struct *vma)
> +{
> + struct sgx_encl *encl = vma->vm_private_data;
> +
> + if (!encl)
> + return;
> +
> + if (sgx_encl_mm_add(encl, vma->vm_mm))
> + vma->vm_private_data = NULL;
> +}
> +
> +static unsigned int sgx_vma_fault(struct vm_fault *vmf)
> +{
> + unsigned long addr = (unsigned long)vmf->address;
> + struct vm_area_struct *vma = vmf->vma;
> + struct sgx_encl *encl = vma->vm_private_data;
> + struct sgx_encl_page *entry;
> + int ret = VM_FAULT_NOPAGE;
> + unsigned long pfn;
> +
> + if (!encl)
> + return VM_FAULT_SIGBUS;
> +
> + mutex_lock(&encl->lock);
> +
> + entry = sgx_encl_load_page(encl, addr);
> + if (IS_ERR(entry)) {
> + if (unlikely(PTR_ERR(entry) != -EBUSY))
> + ret = VM_FAULT_SIGBUS;
> +
> + goto out;
> + }
> +
> + if (!follow_pfn(vma, addr, &pfn))
> + goto out;
> +
> + ret = vmf_insert_pfn(vma, addr, PFN_DOWN(entry->epc_page->desc));
> + if (ret != VM_FAULT_NOPAGE) {
> + ret = VM_FAULT_SIGBUS;
> + goto out;
> + }
> +
> +out:
> + mutex_unlock(&encl->lock);
> + return ret;
> +}
> +
> +/**
> + * sgx_encl_may_map() - Check if a requested VMA mapping is allowed
> + * @encl: an enclave
> + * @start: lower bound of the address range, inclusive
> + * @end: upper bound of the address range, exclusive
> + * @vm_prot_bits: requested protections of the address range
> + *
> + * Iterate through the enclave pages contained within [@start, @end) to verify
> + * the permissions requested by @vm_prot_bits do not exceed that of any enclave
> + * page to be mapped. Page addresses that do not have an associated enclave
> + * page are interpreted to zero permissions.
> + *
> + * Return:
> + * 0 on success,
> + * -EACCES if VMA permissions exceed enclave page permissions
> + */
> +int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start,
> + unsigned long end, unsigned long vm_prot_bits)
> +{
> + unsigned long idx, idx_start, idx_end;
> + struct sgx_encl_page *page;
> +
> + /* PROT_NONE always succeeds. */
> + if (!vm_prot_bits)
> + return 0;
> +
> + idx_start = PFN_DOWN(start);
> + idx_end = PFN_DOWN(end - 1);
> +
> + for (idx = idx_start; idx <= idx_end; ++idx) {
> + mutex_lock(&encl->lock);
> + page = radix_tree_lookup(&encl->page_tree, idx);
> + mutex_unlock(&encl->lock);
> +
> + if (!page || (~page->vm_max_prot_bits & vm_prot_bits))
> + return -EACCES;
> + }
> +
> + return 0;
> +}
> +
> +static int sgx_vma_mprotect(struct vm_area_struct *vma, unsigned long start,
> + unsigned long end, unsigned long prot)
> +{
> + return sgx_encl_may_map(vma->vm_private_data, start, end,
> + calc_vm_prot_bits(prot, 0));
> +}
> +
> +const struct vm_operations_struct sgx_vm_ops = {
> + .open = sgx_vma_open,
> + .fault = sgx_vma_fault,
> + .may_mprotect = sgx_vma_mprotect,
> +};
> +
> +/**
> + * sgx_encl_find - find an enclave
> + * @mm: mm struct of the current process
> + * @addr: address in the ELRANGE
> + * @vma: the resulting VMA
> + *
> + * Find an enclave identified by the given address. Give back a VMA that is
> + * part of the enclave and located in that address. The VMA is given back if it
> + * is a proper enclave VMA even if an &sgx_encl instance does not exist yet
> + * (enclave creation has not been performed).
> + *
> + * Return:
> + * 0 on success,
> + * -EINVAL if an enclave was not found,
> + * -ENOENT if the enclave has not been created yet
> + */
> +int sgx_encl_find(struct mm_struct *mm, unsigned long addr,
> + struct vm_area_struct **vma)
> +{
> + struct vm_area_struct *result;
> + struct sgx_encl *encl;
> +
> + result = find_vma(mm, addr);
> + if (!result || result->vm_ops != &sgx_vm_ops || addr < result->vm_start)
> + return -EINVAL;
> +
> + encl = result->vm_private_data;
> + *vma = result;
> +
> + return encl ? 0 : -ENOENT;
> +}
> +
> +/**
> + * sgx_encl_destroy() - destroy enclave resources
> + * @encl: an &sgx_encl instance
> + */
> +void sgx_encl_destroy(struct sgx_encl *encl)
> +{
> + struct sgx_encl_page *entry;
> + struct radix_tree_iter iter;
> + void **slot;
> +
> + atomic_or(SGX_ENCL_DEAD, &encl->flags);
> +
> + radix_tree_for_each_slot(slot, &encl->page_tree, &iter, 0) {
> + entry = *slot;
> +
> + if (entry->epc_page) {
> + sgx_free_page(entry->epc_page);
> + encl->secs_child_cnt--;
> + entry->epc_page = NULL;
> + }
> +
> + radix_tree_delete(&entry->encl->page_tree,
> + PFN_DOWN(entry->desc));
> + kfree(entry);
> + }
> +
> + if (!encl->secs_child_cnt && encl->secs.epc_page) {
> + sgx_free_page(encl->secs.epc_page);
> + encl->secs.epc_page = NULL;
> + }
> +}
> +
> +/**
> + * sgx_encl_release - Destroy an enclave instance
> + * @kref: address of a kref inside &sgx_encl
> + *
> + * Used together with kref_put(). Frees all the resources associated with the
> + * enclave and the instance itself.
> + */
> +void sgx_encl_release(struct kref *ref)
> +{
> + struct sgx_encl *encl = container_of(ref, struct sgx_encl, refcount);
> +
> + sgx_encl_destroy(encl);
> +
> + if (encl->backing)
> + fput(encl->backing);
> +
> + WARN_ON_ONCE(!list_empty(&encl->mm_list));
> +
> + /* Detect EPC page leak's. */
> + WARN_ON_ONCE(encl->secs_child_cnt);
> + WARN_ON_ONCE(encl->secs.epc_page);
> +
> + kfree(encl);
> +}
> diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h
> new file mode 100644
> index 000000000000..1d1bc5d590ee
> --- /dev/null
> +++ b/arch/x86/kernel/cpu/sgx/encl.h
> @@ -0,0 +1,87 @@
> +/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
> +/**
> + * Copyright(c) 2016-19 Intel Corporation.
> + */
> +#ifndef _X86_ENCL_H
> +#define _X86_ENCL_H
> +
> +#include <linux/cpumask.h>
> +#include <linux/kref.h>
> +#include <linux/list.h>
> +#include <linux/mm_types.h>
> +#include <linux/mmu_notifier.h>
> +#include <linux/mutex.h>
> +#include <linux/notifier.h>
> +#include <linux/radix-tree.h>
> +#include <linux/srcu.h>
> +#include <linux/workqueue.h>
> +#include "sgx.h"
> +
> +/**
> + * enum sgx_encl_page_desc - defines bits for an enclave page's descriptor
> + * %SGX_ENCL_PAGE_ADDR_MASK: Holds the virtual address of the page.
> + *
> + * The page address for SECS is zero and is used by the subsystem to recognize
> + * the SECS page.
> + */
> +enum sgx_encl_page_desc {
> + /* Bits 11:3 are available when the page is not swapped. */
> + SGX_ENCL_PAGE_ADDR_MASK = PAGE_MASK,
> +};
> +
> +#define SGX_ENCL_PAGE_ADDR(page) \
> + ((page)->desc & SGX_ENCL_PAGE_ADDR_MASK)
> +
> +struct sgx_encl_page {
> + unsigned long desc;
> + unsigned long vm_max_prot_bits;
> + struct sgx_epc_page *epc_page;
> + struct sgx_encl *encl;
> +};
> +
> +enum sgx_encl_flags {
> + SGX_ENCL_CREATED = BIT(0),
> + SGX_ENCL_INITIALIZED = BIT(1),
> + SGX_ENCL_DEBUG = BIT(2),
> + SGX_ENCL_DEAD = BIT(3),
> + SGX_ENCL_IOCTL = BIT(4),
> +};
> +
> +struct sgx_encl_mm {
> + struct sgx_encl *encl;
> + struct mm_struct *mm;
> + struct list_head list;
> + struct mmu_notifier mmu_notifier;
> +};
> +
> +struct sgx_encl {
> + atomic_t flags;
> + u64 secs_attributes;
> + u64 allowed_attributes;
> + unsigned int page_cnt;
> + unsigned int secs_child_cnt;
> + struct mutex lock;
> + struct list_head mm_list;
> + spinlock_t mm_lock;
> + struct file *backing;
> + struct kref refcount;
> + struct srcu_struct srcu;
> + unsigned long base;
> + unsigned long size;
> + unsigned long ssaframesize;
> + struct radix_tree_root page_tree;
> + struct sgx_encl_page secs;
> + cpumask_t cpumask;
> +};
> +
> +extern const struct vm_operations_struct sgx_vm_ops;
> +
> +int sgx_encl_find(struct mm_struct *mm, unsigned long addr,
> + struct vm_area_struct **vma);
> +void sgx_encl_destroy(struct sgx_encl *encl);
> +void sgx_encl_release(struct kref *ref);
> +int sgx_encl_mm_add(struct sgx_encl *encl, struct mm_struct *mm);
> +int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start,
> + unsigned long end, unsigned long vm_prot_bits);
> +
> +#endif /* _X86_ENCL_H */
> diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
> new file mode 100644
> index 000000000000..691efac24ed7
> --- /dev/null
> +++ b/arch/x86/kernel/cpu/sgx/ioctl.c
> @@ -0,0 +1,656 @@
> +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
> +// Copyright(c) 2016-19 Intel Corporation.
> +
> +#include <asm/mman.h>
> +#include <linux/mman.h>
> +#include <linux/delay.h>
> +#include <linux/file.h>
> +#include <linux/hashtable.h>
> +#include <linux/highmem.h>
> +#include <linux/ratelimit.h>
> +#include <linux/sched/signal.h>
> +#include <linux/shmem_fs.h>
> +#include <linux/slab.h>
> +#include <linux/suspend.h>
> +#include "driver.h"
> +#include "encl.h"
> +#include "encls.h"
> +
> +static u32 sgx_calc_ssaframesize(u32 miscselect, u64 xfrm)
> +{
> + u32 size_max = PAGE_SIZE;
> + u32 size;
> + int i;
> +
> + for (i = 2; i < 64; i++) {
> + if (!((1 << i) & xfrm))
> + continue;
> +
> + size = SGX_SSA_GPRS_SIZE + sgx_xsave_size_tbl[i];
> + if (miscselect & SGX_MISC_EXINFO)
> + size += SGX_SSA_MISC_EXINFO_SIZE;
> +
> + if (size > size_max)
> + size_max = size;
> + }
> +
> + return PFN_UP(size_max);
> +}
> +
> +static int sgx_validate_secs(const struct sgx_secs *secs,
> + unsigned long ssaframesize)
> +{
> + if (secs->size < (2 * PAGE_SIZE) || !is_power_of_2(secs->size))
> + return -EINVAL;
> +
> + if (secs->base & (secs->size - 1))
> + return -EINVAL;
> +
> + if (secs->miscselect & sgx_misc_reserved_mask ||
> + secs->attributes & sgx_attributes_reserved_mask ||
> + secs->xfrm & sgx_xfrm_reserved_mask)
> + return -EINVAL;
> +
> + if (secs->attributes & SGX_ATTR_MODE64BIT) {
> + if (secs->size > sgx_encl_size_max_64)
> + return -EINVAL;
> + } else if (secs->size > sgx_encl_size_max_32)
> + return -EINVAL;
> +
> + if (!(secs->xfrm & XFEATURE_MASK_FP) ||
> + !(secs->xfrm & XFEATURE_MASK_SSE) ||
> + (((secs->xfrm >> XFEATURE_BNDREGS) & 1) !=
> + ((secs->xfrm >> XFEATURE_BNDCSR) & 1)))
> + return -EINVAL;
> +
> + if (!secs->ssa_frame_size || ssaframesize > secs->ssa_frame_size)
> + return -EINVAL;
> +
> + if (memchr_inv(secs->reserved1, 0, sizeof(secs->reserved1)) ||
> + memchr_inv(secs->reserved2, 0, sizeof(secs->reserved2)) ||
> + memchr_inv(secs->reserved3, 0, sizeof(secs->reserved3)) ||
> + memchr_inv(secs->reserved4, 0, sizeof(secs->reserved4)))
> + return -EINVAL;
> +
> + return 0;
> +}
> +
> +static struct sgx_encl_page *sgx_encl_page_alloc(struct sgx_encl *encl,
> + unsigned long offset,
> + u64 secinfo_flags)
> +{
> + struct sgx_encl_page *encl_page;
> + unsigned long prot;
> +
> + encl_page = kzalloc(sizeof(*encl_page), GFP_KERNEL);
> + if (!encl_page)
> + return ERR_PTR(-ENOMEM);
> +
> + encl_page->desc = encl->base + offset;
> + encl_page->encl = encl;
> +
> + prot = _calc_vm_trans(secinfo_flags, SGX_SECINFO_R, PROT_READ) |
> + _calc_vm_trans(secinfo_flags, SGX_SECINFO_W, PROT_WRITE) |
> + _calc_vm_trans(secinfo_flags, SGX_SECINFO_X, PROT_EXEC);
> +
> + /*
> + * TCS pages must always RW set for CPU access while the SECINFO
> + * permissions are *always* zero - the CPU ignores the user provided
> + * values and silently overwrites them with zero permissions.
> + */
> + if ((secinfo_flags & SGX_SECINFO_PAGE_TYPE_MASK) == SGX_SECINFO_TCS)
> + prot |= PROT_READ | PROT_WRITE;
> +
> + /* Calculate maximum of the VM flags for the page. */
> + encl_page->vm_max_prot_bits = calc_vm_prot_bits(prot, 0);
> +
> + return encl_page;
> +}
> +
> +static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs)
> +{
> + unsigned long encl_size = secs->size + PAGE_SIZE;
> + struct sgx_epc_page *secs_epc;
> + unsigned long ssaframesize;
> + struct sgx_pageinfo pginfo;
> + struct sgx_secinfo secinfo;
> + struct file *backing;
> + long ret;
> +
> + if (atomic_read(&encl->flags) & SGX_ENCL_CREATED)
> + return -EINVAL;
> +
> + ssaframesize = sgx_calc_ssaframesize(secs->miscselect, secs->xfrm);
> + if (sgx_validate_secs(secs, ssaframesize)) {
> + pr_debug("invalid SECS\n");
> + return -EINVAL;
> + }
> +
> + backing = shmem_file_setup("SGX backing", encl_size + (encl_size >> 5),
> + VM_NORESERVE);
> + if (IS_ERR(backing))
> + return PTR_ERR(backing);
> +
> + encl->backing = backing;
> +
> + secs_epc = sgx_try_alloc_page();
> + if (IS_ERR(secs_epc)) {
> + ret = PTR_ERR(secs_epc);
> + goto err_out_backing;
> + }
> +
> + encl->secs.epc_page = secs_epc;
> +
> + pginfo.addr = 0;
> + pginfo.contents = (unsigned long)secs;
> + pginfo.metadata = (unsigned long)&secinfo;
> + pginfo.secs = 0;
> + memset(&secinfo, 0, sizeof(secinfo));
> +
> + ret = __ecreate((void *)&pginfo, sgx_epc_addr(secs_epc));
> + if (ret) {
> + pr_debug("ECREATE returned %ld\n", ret);
> + goto err_out;
> + }
> +
> + if (secs->attributes & SGX_ATTR_DEBUG)
> + atomic_or(SGX_ENCL_DEBUG, &encl->flags);
> +
> + encl->secs.encl = encl;
> + encl->secs_attributes = secs->attributes;
> + encl->allowed_attributes |= SGX_ATTR_ALLOWED_MASK;
> + encl->base = secs->base;
> + encl->size = secs->size;
> + encl->ssaframesize = secs->ssa_frame_size;
> +
> + /*
> + * Set SGX_ENCL_CREATED only after the enclave is fully prepped. This
> + * allows setting and checking enclave creation without having to take
> + * encl->lock.
> + */
> + atomic_or(SGX_ENCL_CREATED, &encl->flags);
> +
> + return 0;
> +
> +err_out:
> + sgx_free_page(encl->secs.epc_page);
> + encl->secs.epc_page = NULL;
> +
> +err_out_backing:
> + fput(encl->backing);
> + encl->backing = NULL;
> +
> + return ret;
> +}
> +
> +/**
> + * sgx_ioc_enclave_create - handler for %SGX_IOC_ENCLAVE_CREATE
> + * @filep: open file to /dev/sgx
> + * @arg: userspace pointer to a struct sgx_enclave_create instance
> + *
> + * Allocate kernel data structures for a new enclave and execute ECREATE after
> + * verifying the correctness of the provided SECS.
> + *
> + * Note, enforcement of restricted and disallowed attributes is deferred until
> + * sgx_ioc_enclave_init(), only the architectural correctness of the SECS is
> + * checked by sgx_ioc_enclave_create().
> + *
> + * Return:
> + * 0 on success,
> + * -errno otherwise
> + */
> +static long sgx_ioc_enclave_create(struct sgx_encl *encl, void __user *arg)
> +{
> + struct sgx_enclave_create ecreate;
> + struct page *secs_page;
> + struct sgx_secs *secs;
> + int ret;
> +
> + if (copy_from_user(&ecreate, arg, sizeof(ecreate)))
> + return -EFAULT;
> +
> + secs_page = alloc_page(GFP_HIGHUSER);
> + if (!secs_page)
> + return -ENOMEM;
> +
> + secs = kmap(secs_page);
> + if (copy_from_user(secs, (void __user *)ecreate.src, sizeof(*secs))) {
> + ret = -EFAULT;
> + goto out;
> + }
> +
> + ret = sgx_encl_create(encl, secs);
> +
> +out:
> + kunmap(secs_page);
> + __free_page(secs_page);
> + return ret;
> +}
> +
> +static int sgx_validate_secinfo(struct sgx_secinfo *secinfo)
> +{
> + u64 perm = secinfo->flags & SGX_SECINFO_PERMISSION_MASK;
> + u64 pt = secinfo->flags & SGX_SECINFO_PAGE_TYPE_MASK;
> +
> + if (pt != SGX_SECINFO_REG && pt != SGX_SECINFO_TCS)
> + return -EINVAL;
> +
> + if ((perm & SGX_SECINFO_W) && !(perm & SGX_SECINFO_R))
> + return -EINVAL;
> +
> + /*
> + * CPU will silently overwrite the permissions as zero, which means
> + * that we need to validate it ourselves.
> + */
> + if (pt == SGX_SECINFO_TCS && perm)
> + return -EINVAL;
> +
> + if (secinfo->flags & SGX_SECINFO_RESERVED_MASK)
> + return -EINVAL;
> +
> + if (memchr_inv(secinfo->reserved, 0, sizeof(secinfo->reserved)))
> + return -EINVAL;
> +
> + return 0;
> +}
> +
> +static int __sgx_encl_add_page(struct sgx_encl *encl,
> + struct sgx_encl_page *encl_page,
> + struct sgx_epc_page *epc_page,
> + struct sgx_secinfo *secinfo, unsigned long src)
> +{
> + struct sgx_pageinfo pginfo;
> + struct vm_area_struct *vma;
> + struct page *src_page;
> + int ret;
> +
> + /* Query vma's VM_MAYEXEC as an indirect path_noexec() check. */
> + if (encl_page->vm_max_prot_bits & VM_EXEC) {
> + vma = find_vma(current->mm, src);
> + if (!vma)
> + return -EFAULT;
> +
> + if (!(vma->vm_flags & VM_MAYEXEC))
> + return -EACCES;
> + }
> +
> + ret = get_user_pages(src, 1, 0, &src_page, NULL);
> + if (ret < 1)
> + return ret;
> +
> + pginfo.secs = (unsigned long)sgx_epc_addr(encl->secs.epc_page);
> + pginfo.addr = SGX_ENCL_PAGE_ADDR(encl_page);
> + pginfo.metadata = (unsigned long)secinfo;
> + pginfo.contents = (unsigned long)kmap_atomic(src_page);
> +
> + ret = __eadd(&pginfo, sgx_epc_addr(epc_page));
> +
> + kunmap_atomic((void *)pginfo.contents);
> + put_page(src_page);
> +
> + return ret ? -EFAULT : 0;
> +}
> +
> +static int __sgx_encl_extend(struct sgx_encl *encl,
> + struct sgx_epc_page *epc_page)
> +{
> + int ret;
> + int i;
> +
> + for (i = 0; i < 16; i++) {
> + ret = __eextend(sgx_epc_addr(encl->secs.epc_page),
> + sgx_epc_addr(epc_page) + (i * 0x100));
> + if (ret) {
> + if (encls_failed(ret))
> + ENCLS_WARN(ret, "EEXTEND");
> + return -EFAULT;
> + }
> + }
> +
> + return 0;
> +}
> +
> +static int sgx_encl_add_page(struct sgx_encl *encl,
> + struct sgx_enclave_add_pages *addp,
> + struct sgx_secinfo *secinfo)
> +{
> + struct sgx_encl_page *encl_page;
> + struct sgx_epc_page *epc_page;
> + int ret;
> +
> + encl_page = sgx_encl_page_alloc(encl, addp->offset, secinfo->flags);
> + if (IS_ERR(encl_page))
> + return PTR_ERR(encl_page);
> +
> + epc_page = sgx_try_alloc_page();
> + if (IS_ERR(epc_page)) {
> + kfree(encl_page);
> + return PTR_ERR(epc_page);
> + }
> +
> + if (atomic_read(&encl->flags) &
> + (SGX_ENCL_INITIALIZED | SGX_ENCL_DEAD)) {
> + ret = -EFAULT;
> + goto err_out_free;
> + }
> +
> + down_read(¤t->mm->mmap_sem);
> + mutex_lock(&encl->lock);
> +
> + /*
> + * Insert prior to EADD in case of OOM. EADD modifies MRENCLAVE, i.e.
> + * can't be gracefully unwound, while failure on EADD/EXTEND is limited
> + * to userspace errors (or kernel/hardware bugs).
> + */
> + ret = radix_tree_insert(&encl->page_tree, PFN_DOWN(encl_page->desc),
> + encl_page);
> + if (ret)
> + goto err_out_unlock;
> +
> + ret = __sgx_encl_add_page(encl, encl_page, epc_page, secinfo,
> + addp->src);
> + if (ret)
> + goto err_out;
> +
> + /*
> + * Complete the "add" before doing the "extend" so that the "add"
> + * isn't in a half-baked state in the extremely unlikely scenario the
> + * the enclave will be destroyed in response to EEXTEND failure.
> + */
> + encl_page->encl = encl;
> + encl_page->epc_page = epc_page;
> + encl->secs_child_cnt++;
> +
> + if (addp->flags & SGX_PAGE_MEASURE) {
> + ret = __sgx_encl_extend(encl, epc_page);
> + if (ret)
> + sgx_encl_destroy(encl);
> + }
> +
> + mutex_unlock(&encl->lock);
> + up_read(¤t->mm->mmap_sem);
> + return ret;
> +
> +err_out:
> + radix_tree_delete(&encl_page->encl->page_tree,
> + PFN_DOWN(encl_page->desc));
> +
> +err_out_unlock:
> + mutex_unlock(&encl->lock);
> + up_read(¤t->mm->mmap_sem);
> +
> +err_out_free:
> + sgx_free_page(epc_page);
> + kfree(encl_page);
> +
> + return ret;
> +}
> +
> +/**
> + * sgx_ioc_enclave_add_pages() - The handler for %SGX_IOC_ENCLAVE_ADD_PAGES
> + * @encl: pointer to an enclave instance (via ioctl() file pointer)
> + * @arg: a user pointer to a struct sgx_enclave_add_pages instance
> + *
> + * Add (EADD) one or more pages to an uninitialized enclave, and optionally
> + * extend (EEXTEND) the measurement with the contents of the page. The range of
> + * pages must be virtually contiguous. The SECINFO and measurement mask are
> + * applied to all pages, i.e. pages with different properties must be added in
> + * separate calls.
> + *
> + * A SECINFO for a TCS is required to always contain zero permissions because
> + * CPU silently zeros them. Allowing anything else would cause a mismatch in
> + * the measurement.
> + *
> + * mmap()'s protection bits are capped by the page permissions. For each page
> + * address, the maximum protection bits are computed with the following
> + * heuristics:
> + *
> + * 1. A regular page: PROT_R, PROT_W and PROT_X match the SECINFO permissions.
> + * 2. A TCS page: PROT_R | PROT_W.
> + * 3. No page: PROT_NONE.
> + *
> + * mmap() is not allowed to surpass the minimum of the maximum protection bits
> + * within the given address range.
> + *
> + * As stated above, a non-existent page is interpreted as a page with no
> + * permissions. In effect, this allows mmap() with PROT_NONE to be used to seek
> + * an address range for the enclave that can be then populated into SECS.
> + *
> + * @arg->addr, @arg->src and @arg->length are adjusted to reflect the
> + * remaining pages that need to be added to the enclave, e.g. userspace can
> + * re-invoke SGX_IOC_ENCLAVE_ADD_PAGES using the same struct in response to an
> + * ERESTARTSYS error.
> + *
> + * Return:
> + * 0 on success,
> + * -EINVAL if any input param or the SECINFO contains invalid data,
> + * -EACCES if an executable source page is located in a noexec partition,
> + * -ENOMEM if any memory allocation, including EPC, fails,
> + * -ERESTARTSYS if a pending signal is recognized
> + */
> +static long sgx_ioc_enclave_add_pages(struct sgx_encl *encl, void __user *arg)
> +{
> + struct sgx_enclave_add_pages addp;
> + struct sgx_secinfo secinfo;
> + int ret;
> +
> + if (!(atomic_read(&encl->flags) & SGX_ENCL_CREATED))
> + return -EINVAL;
> +
> + if (copy_from_user(&addp, arg, sizeof(addp)))
> + return -EFAULT;
> +
> + if (!IS_ALIGNED(addp.offset, PAGE_SIZE) ||
> + !IS_ALIGNED(addp.src, PAGE_SIZE))
> + return -EINVAL;
> +
> + if (!(access_ok(addp.src, PAGE_SIZE)))
> + return -EFAULT;
> +
> + if (addp.length & (PAGE_SIZE - 1))
> + return -EINVAL;
> +
> + if (addp.offset + addp.length - PAGE_SIZE >= encl->size)
> + return -EINVAL;
> +
> + if (copy_from_user(&secinfo, (void __user *)addp.secinfo,
> + sizeof(secinfo)))
> + return -EFAULT;
> +
> + if (sgx_validate_secinfo(&secinfo))
> + return -EINVAL;
> +
> + for ( ; addp.length > 0; addp.length -= PAGE_SIZE) {
> + if (signal_pending(current)) {
> + ret = -ERESTARTSYS;
> + break;
> + }
> +
> + if (need_resched())
> + cond_resched();
> +
> + ret = sgx_encl_add_page(encl, &addp, &secinfo);
> + if (ret)
> + break;
> +
> + addp.offset += PAGE_SIZE;
> + addp.src += PAGE_SIZE;
> + }
> +
> + if (copy_to_user(arg, &addp, sizeof(addp)))
> + return -EFAULT;
> +
> + return ret;
> +}
> +
> +static int __sgx_get_key_hash(struct crypto_shash *tfm, const void *modulus,
> + void *hash)
> +{
> + SHASH_DESC_ON_STACK(shash, tfm);
> +
> + shash->tfm = tfm;
> +
> + return crypto_shash_digest(shash, modulus, SGX_MODULUS_SIZE, hash);
> +}
> +
> +static int sgx_get_key_hash(const void *modulus, void *hash)
> +{
> + struct crypto_shash *tfm;
> + int ret;
> +
> + tfm = crypto_alloc_shash("sha256", 0, CRYPTO_ALG_ASYNC);
> + if (IS_ERR(tfm))
> + return PTR_ERR(tfm);
> +
> + ret = __sgx_get_key_hash(tfm, modulus, hash);
> +
> + crypto_free_shash(tfm);
> + return ret;
> +}
> +
> +static int sgx_encl_init(struct sgx_encl *encl, struct sgx_sigstruct *sigstruct,
> + struct sgx_einittoken *token)
> +{
> + u64 mrsigner[4];
> + int ret;
> + int i;
> + int j;
> +
> + /* Check that the required attributes have been authorized. */
> + if (encl->secs_attributes & ~encl->allowed_attributes)
> + return -EINVAL;
> +
> + ret = sgx_get_key_hash(sigstruct->modulus, mrsigner);
> + if (ret)
> + return ret;
> +
> + mutex_lock(&encl->lock);
> +
> + if (atomic_read(&encl->flags) & SGX_ENCL_INITIALIZED) {
> + ret = -EFAULT;
> + goto err_out;
> + }
> +
> + for (i = 0; i < SGX_EINIT_SLEEP_COUNT; i++) {
> + for (j = 0; j < SGX_EINIT_SPIN_COUNT; j++) {
> + ret = sgx_einit(sigstruct, token, encl->secs.epc_page,
> + mrsigner);
> + if (ret == SGX_UNMASKED_EVENT)
> + continue;
> + else
> + break;
> + }
> +
> + if (ret != SGX_UNMASKED_EVENT)
> + break;
> +
> + msleep_interruptible(SGX_EINIT_SLEEP_TIME);
> +
> + if (signal_pending(current)) {
> + ret = -ERESTARTSYS;
> + goto err_out;
> + }
> + }
> +
> + if (ret & ENCLS_FAULT_FLAG) {
> + if (encls_failed(ret))
> + ENCLS_WARN(ret, "EINIT");
> +
> + sgx_encl_destroy(encl);
> + ret = -EFAULT;
> + } else if (ret) {
> + pr_debug("EINIT returned %d\n", ret);
> + ret = -EPERM;
> + } else {
> + atomic_or(SGX_ENCL_INITIALIZED, &encl->flags);
> + }
> +
> +err_out:
> + mutex_unlock(&encl->lock);
> + return ret;
> +}
> +
> +/**
> + * sgx_ioc_enclave_init - handler for %SGX_IOC_ENCLAVE_INIT
> + *
> + * @filep: open file to /dev/sgx
> + * @arg: userspace pointer to a struct sgx_enclave_init instance
> + *
> + * Flush any outstanding enqueued EADD operations and perform EINIT. The
> + * Launch Enclave Public Key Hash MSRs are rewritten as necessary to match
> + * the enclave's MRSIGNER, which is caculated from the provided sigstruct.
> + *
> + * Return:
> + * 0 on success,
> + * SGX error code on EINIT failure,
> + * -errno otherwise
> + */
> +static long sgx_ioc_enclave_init(struct sgx_encl *encl, void __user *arg)
> +{
> + struct sgx_einittoken *einittoken;
> + struct sgx_sigstruct *sigstruct;
> + struct sgx_enclave_init einit;
> + struct page *initp_page;
> + int ret;
> +
> + if (!(atomic_read(&encl->flags) & SGX_ENCL_CREATED))
> + return -EINVAL;
> +
> + if (copy_from_user(&einit, arg, sizeof(einit)))
> + return -EFAULT;
> +
> + initp_page = alloc_page(GFP_HIGHUSER);
> + if (!initp_page)
> + return -ENOMEM;
> +
> + sigstruct = kmap(initp_page);
> + einittoken = (struct sgx_einittoken *)
> + ((unsigned long)sigstruct + PAGE_SIZE / 2);
> + memset(einittoken, 0, sizeof(*einittoken));
> +
> + if (copy_from_user(sigstruct, (void __user *)einit.sigstruct,
> + sizeof(*sigstruct))) {
> + ret = -EFAULT;
> + goto out;
> + }
> +
> + ret = sgx_encl_init(encl, sigstruct, einittoken);
> +
> +out:
> + kunmap(initp_page);
> + __free_page(initp_page);
> + return ret;
> +}
> +
> +
> +long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
> +{
> + struct sgx_encl *encl = filep->private_data;
> + int ret, encl_flags;
> +
> + encl_flags = atomic_fetch_or(SGX_ENCL_IOCTL, &encl->flags);
> + if (encl_flags & SGX_ENCL_IOCTL)
> + return -EBUSY;
> +
> + if (encl_flags & SGX_ENCL_DEAD)
> + return -EFAULT;
> +
> + switch (cmd) {
> + case SGX_IOC_ENCLAVE_CREATE:
> + ret = sgx_ioc_enclave_create(encl, (void __user *)arg);
> + break;
> + case SGX_IOC_ENCLAVE_ADD_PAGES:
> + ret = sgx_ioc_enclave_add_pages(encl, (void __user *)arg);
> + break;
> + case SGX_IOC_ENCLAVE_INIT:
> + ret = sgx_ioc_enclave_init(encl, (void __user *)arg);
> + break;
> + default:
> + ret = -ENOIOCTLCMD;
> + break;
> + }
> +
> + atomic_andnot(SGX_ENCL_IOCTL, &encl->flags);
> +
> + return ret;
> +}
> diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
> index 6a37df61ae32..36a295a0272b 100644
> --- a/arch/x86/kernel/cpu/sgx/main.c
> +++ b/arch/x86/kernel/cpu/sgx/main.c
> @@ -8,6 +8,7 @@
> #include <linux/ratelimit.h>
> #include <linux/sched/signal.h>
> #include <linux/slab.h>
> +#include "driver.h"
> #include "encls.h"
>
> struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
> @@ -196,6 +197,8 @@ static bool __init sgx_page_cache_init(void)
>
> static void __init sgx_init(void)
> {
> + int ret;
> +
> if (!boot_cpu_has(X86_FEATURE_SGX))
> return;
>
> @@ -205,8 +208,15 @@ static void __init sgx_init(void)
> if (!sgx_page_reclaimer_init())
> goto err_page_cache;
>
> + ret = sgx_drv_init();
> + if (ret)
> + goto err_kthread;
> +
> return;
>
> +err_kthread:
> + kthread_stop(ksgxswapd_tsk);
> +
> err_page_cache:
> sgx_page_cache_teardown();
> }
> diff --git a/arch/x86/kernel/cpu/sgx/reclaim.c b/arch/x86/kernel/cpu/sgx/reclaim.c
> index f071158d34f6..bdb42f4326aa 100644
> --- a/arch/x86/kernel/cpu/sgx/reclaim.c
> +++ b/arch/x86/kernel/cpu/sgx/reclaim.c
> @@ -10,6 +10,7 @@
> #include <linux/sched/mm.h>
> #include <linux/sched/signal.h>
> #include "encls.h"
> +#include "driver.h"
>
> struct task_struct *ksgxswapd_tsk;
>
>
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