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|
// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2016-20 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 int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs)
{
struct sgx_epc_page *secs_epc;
struct sgx_pageinfo pginfo;
struct sgx_secinfo secinfo;
unsigned long encl_size;
long ret;
/* The extra page goes to SECS. */
encl_size = secs->size + PAGE_SIZE;
secs_epc = __sgx_alloc_epc_page();
if (IS_ERR(secs_epc))
return PTR_ERR(secs_epc);
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_get_epc_virt_addr(secs_epc));
if (ret) {
ret = -EIO;
goto err_out;
}
if (secs->attributes & SGX_ATTR_DEBUG)
set_bit(SGX_ENCL_DEBUG, &encl->flags);
encl->secs.encl = encl;
encl->base = secs->base;
encl->size = secs->size;
encl->attributes = secs->attributes;
encl->attributes_mask = SGX_ATTR_DEBUG | SGX_ATTR_MODE64BIT | SGX_ATTR_KSS;
/* Set only after completion, as encl->lock has not been taken. */
set_bit(SGX_ENCL_CREATED, &encl->flags);
return 0;
err_out:
sgx_free_epc_page(encl->secs.epc_page);
encl->secs.epc_page = NULL;
return ret;
}
/**
* sgx_ioc_enclave_create() - handler for %SGX_IOC_ENCLAVE_CREATE
* @encl: An enclave pointer.
* @arg: The ioctl argument.
*
* Allocate kernel data structures for the enclave and invoke ECREATE.
*
* Return:
* - 0: Success.
* - -EIO: ECREATE failed.
* - -errno: POSIX error.
*/
static long sgx_ioc_enclave_create(struct sgx_encl *encl, void __user *arg)
{
struct sgx_enclave_create create_arg;
void *secs;
int ret;
if (test_bit(SGX_ENCL_CREATED, &encl->flags))
return -EINVAL;
if (copy_from_user(&create_arg, arg, sizeof(create_arg)))
return -EFAULT;
secs = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!secs)
return -ENOMEM;
if (copy_from_user(secs, (void __user *)create_arg.src, PAGE_SIZE))
ret = -EFAULT;
else
ret = sgx_encl_create(encl, secs);
kfree(secs);
return ret;
}
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_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;
/* Deny noexec. */
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 -EFAULT;
pginfo.secs = (unsigned long)sgx_get_epc_virt_addr(encl->secs.epc_page);
pginfo.addr = encl_page->desc & PAGE_MASK;
pginfo.metadata = (unsigned long)secinfo;
pginfo.contents = (unsigned long)kmap_atomic(src_page);
ret = __eadd(&pginfo, sgx_get_epc_virt_addr(epc_page));
kunmap_atomic((void *)pginfo.contents);
put_page(src_page);
return ret ? -EIO : 0;
}
/*
* If the caller requires measurement of the page as a proof for the content,
* use EEXTEND to add a measurement for 256 bytes of the page. Repeat this
* operation until the entire page is measured."
*/
static int __sgx_encl_extend(struct sgx_encl *encl,
struct sgx_epc_page *epc_page)
{
unsigned long offset;
int ret;
for (offset = 0; offset < PAGE_SIZE; offset += SGX_EEXTEND_BLOCK_SIZE) {
ret = __eextend(sgx_get_epc_virt_addr(encl->secs.epc_page),
sgx_get_epc_virt_addr(epc_page) + offset);
if (ret) {
if (encls_failed(ret))
ENCLS_WARN(ret, "EEXTEND");
return -EIO;
}
}
return 0;
}
static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long src,
unsigned long offset, struct sgx_secinfo *secinfo,
unsigned long flags)
{
struct sgx_encl_page *encl_page;
struct sgx_epc_page *epc_page;
int ret;
encl_page = sgx_encl_page_alloc(encl, offset, secinfo->flags);
if (IS_ERR(encl_page))
return PTR_ERR(encl_page);
epc_page = __sgx_alloc_epc_page();
if (IS_ERR(epc_page)) {
kfree(encl_page);
return PTR_ERR(epc_page);
}
mmap_read_lock(current->mm);
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 = xa_insert(&encl->page_array, PFN_DOWN(encl_page->desc),
encl_page, GFP_KERNEL);
if (ret)
goto err_out_unlock;
ret = __sgx_encl_add_page(encl, encl_page, epc_page, secinfo,
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 enclave will be destroyed in response to EEXTEND failure.
*/
encl_page->encl = encl;
encl_page->epc_page = epc_page;
encl->secs_child_cnt++;
if (flags & SGX_PAGE_MEASURE) {
ret = __sgx_encl_extend(encl, epc_page);
if (ret)
goto err_out;
}
mutex_unlock(&encl->lock);
mmap_read_unlock(current->mm);
return ret;
err_out:
xa_erase(&encl->page_array, PFN_DOWN(encl_page->desc));
err_out_unlock:
mutex_unlock(&encl->lock);
mmap_read_unlock(current->mm);
sgx_free_epc_page(epc_page);
kfree(encl_page);
return ret;
}
/**
* sgx_ioc_enclave_add_pages() - The handler for %SGX_IOC_ENCLAVE_ADD_PAGES
* @encl: an enclave pointer
* @arg: a user pointer to a struct sgx_enclave_add_pages instance
*
* Add one or more pages to an uninitialized enclave, and optionally extend the
* measurement with the contents of the page. The SECINFO and measurement mask
* are applied to all pages.
*
* 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.
*
* mmap() is not allowed to surpass the minimum of the maximum protection bits
* within the given address range.
*
* The function deinitializes kernel data structures for enclave and returns
* -EIO in any of the following conditions:
*
* - Enclave Page Cache (EPC), the physical memory holding enclaves, has
* been invalidated. This will cause EADD and EEXTEND to fail.
* - If the source address is corrupted somehow when executing EADD.
*
* Return:
* - 0: Success.
* - -EACCES: The source page is located in a noexec partition.
* - -ENOMEM: Out of EPC pages.
* - -EINTR: The call was interrupted before data was processed.
* - -EIO: Either EADD or EEXTEND failed because invalid source address
* or power cycle.
* - -errno: POSIX error.
*/
static long sgx_ioc_enclave_add_pages(struct sgx_encl *encl, void __user *arg)
{
struct sgx_enclave_add_pages add_arg;
struct sgx_secinfo secinfo;
unsigned long c;
int ret;
if (!test_bit(SGX_ENCL_CREATED, &encl->flags) ||
test_bit(SGX_ENCL_INITIALIZED, &encl->flags))
return -EINVAL;
if (copy_from_user(&add_arg, arg, sizeof(add_arg)))
return -EFAULT;
if (!IS_ALIGNED(add_arg.offset, PAGE_SIZE) ||
!IS_ALIGNED(add_arg.src, PAGE_SIZE))
return -EINVAL;
if (add_arg.length & (PAGE_SIZE - 1))
return -EINVAL;
if (add_arg.offset + add_arg.length - PAGE_SIZE >= encl->size)
return -EINVAL;
if (copy_from_user(&secinfo, (void __user *)add_arg.secinfo,
sizeof(secinfo)))
return -EFAULT;
if (sgx_validate_secinfo(&secinfo))
return -EINVAL;
for (c = 0 ; c < add_arg.length; c += PAGE_SIZE) {
if (signal_pending(current)) {
if (!c)
ret = -EINTR;
break;
}
if (need_resched())
cond_resched();
ret = sgx_encl_add_page(encl, add_arg.src + c, add_arg.offset + c,
&secinfo, add_arg.flags);
if (ret)
break;
}
add_arg.count = c;
if (copy_to_user(arg, &add_arg, sizeof(add_arg)))
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,
void *token)
{
u64 mrsigner[4];
int i, j, k;
void *addr;
int ret;
/*
* Deny initializing enclaves with attributes (namely provisioning)
* that have not been explicitly allowed.
*/
if (encl->attributes & ~encl->attributes_mask)
return -EACCES;
/*
* Attributes should not be enforced *only* against what's available on
* platform (done in sgx_encl_create) but checked and enforced against
* the mask for enforcement in sigstruct. For example an enclave could
* opt to sign with AVX bit in xfrm, but still be loadable on a platform
* without it if the sigstruct->body.attributes_mask does not turn that
* bit on.
*/
if (sigstruct->body.attributes & sigstruct->body.attributes_mask &
sgx_attributes_reserved_mask)
return -EINVAL;
if (sigstruct->body.miscselect & sigstruct->body.misc_mask &
sgx_misc_reserved_mask)
return -EINVAL;
if (sigstruct->body.xfrm & sigstruct->body.xfrm_mask &
sgx_xfrm_reserved_mask)
return -EINVAL;
ret = sgx_get_key_hash(sigstruct->modulus, mrsigner);
if (ret)
return ret;
mutex_lock(&encl->lock);
/*
* ENCLS[EINIT] is interruptible because it has such a high latency,
* e.g. 50k+ cycles on success. If an IRQ/NMI/SMI becomes pending,
* EINIT may fail with SGX_UNMASKED_EVENT so that the event can be
* serviced.
*/
for (i = 0; i < SGX_EINIT_SLEEP_COUNT; i++) {
for (j = 0; j < SGX_EINIT_SPIN_COUNT; j++) {
addr = sgx_get_epc_virt_addr(encl->secs.epc_page);
preempt_disable();
for (k = 0; k < 4; k++)
wrmsrl(MSR_IA32_SGXLEPUBKEYHASH0 + k, mrsigner[k]);
ret = __einit(sigstruct, token, addr);
preempt_enable();
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");
ret = -EIO;
} else if (ret) {
pr_debug("EINIT returned %d\n", ret);
ret = -EPERM;
} else {
set_bit(SGX_ENCL_INITIALIZED, &encl->flags);
}
err_out:
mutex_unlock(&encl->lock);
return ret;
}
/**
* sgx_ioc_enclave_init() - handler for %SGX_IOC_ENCLAVE_INIT
* @encl: an enclave pointer
* @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: Success.
* - -EPERM: Invalid SIGSTRUCT.
* - -EIO: EINIT failed because of a power cycle.
* - -errno: POSIX error.
*/
static long sgx_ioc_enclave_init(struct sgx_encl *encl, void __user *arg)
{
struct sgx_sigstruct *sigstruct;
struct sgx_enclave_init init_arg;
struct page *initp_page;
void *token;
int ret;
if (!test_bit(SGX_ENCL_CREATED, &encl->flags) ||
test_bit(SGX_ENCL_INITIALIZED, &encl->flags))
return -EINVAL;
if (copy_from_user(&init_arg, arg, sizeof(init_arg)))
return -EFAULT;
initp_page = alloc_page(GFP_KERNEL);
if (!initp_page)
return -ENOMEM;
sigstruct = kmap(initp_page);
token = (void *)((unsigned long)sigstruct + PAGE_SIZE / 2);
memset(token, 0, SGX_LAUNCH_TOKEN_SIZE);
if (copy_from_user(sigstruct, (void __user *)init_arg.sigstruct,
sizeof(*sigstruct))) {
ret = -EFAULT;
goto out;
}
/*
* A legacy field used with Intel signed enclaves. These used to mean
* regular and architectural enclaves. The CPU only accepts these values
* but they do not have any other meaning.
*
* Thus, reject any other values.
*/
if (sigstruct->header.vendor != 0x0000 &&
sigstruct->header.vendor != 0x8086) {
ret = -EINVAL;
goto out;
}
ret = sgx_encl_init(encl, sigstruct, token);
out:
kunmap(initp_page);
__free_page(initp_page);
return ret;
}
/**
* sgx_ioc_enclave_provision() - handler for %SGX_IOC_ENCLAVE_PROVISION
* @enclave: an enclave pointer
* @arg: userspace pointer to a struct sgx_enclave_provision instance
*
* Allow ATTRIBUTE.PROVISION_KEY for an enclave by providing a file handle to
* /dev/sgx_provision.
*
* Return:
* - 0: Success.
* - -errno: Otherwise.
*/
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(¶ms, 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;
}
long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
{
struct sgx_encl *encl = filep->private_data;
int ret;
if (test_and_set_bit(SGX_ENCL_IOCTL, &encl->flags))
return -EBUSY;
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;
case SGX_IOC_ENCLAVE_PROVISION:
ret = sgx_ioc_enclave_provision(encl, (void __user *)arg);
break;
default:
ret = -ENOIOCTLCMD;
break;
}
clear_bit(SGX_ENCL_IOCTL, &encl->flags);
return ret;
}
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