diff options
Diffstat (limited to 'arch/x86/kernel/cpu/sgx/ioctl.c')
| -rw-r--r-- | arch/x86/kernel/cpu/sgx/ioctl.c | 1263 |
1 files changed, 1263 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c new file mode 100644 index 000000000..da8b8ea6b --- /dev/null +++ b/arch/x86/kernel/cpu/sgx/ioctl.c @@ -0,0 +1,1263 @@ +// SPDX-License-Identifier: GPL-2.0 +/* 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> +#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" + +struct sgx_va_page *sgx_encl_grow(struct sgx_encl *encl, bool reclaim) +{ + struct sgx_va_page *va_page = NULL; + void *err; + + BUILD_BUG_ON(SGX_VA_SLOT_COUNT != + (SGX_ENCL_PAGE_VA_OFFSET_MASK >> 3) + 1); + + if (!(encl->page_cnt % SGX_VA_SLOT_COUNT)) { + va_page = kzalloc(sizeof(*va_page), GFP_KERNEL); + if (!va_page) + return ERR_PTR(-ENOMEM); + + va_page->epc_page = sgx_alloc_va_page(reclaim); + if (IS_ERR(va_page->epc_page)) { + err = ERR_CAST(va_page->epc_page); + kfree(va_page); + return err; + } + + WARN_ON_ONCE(encl->page_cnt % SGX_VA_SLOT_COUNT); + } + encl->page_cnt++; + return va_page; +} + +void sgx_encl_shrink(struct sgx_encl *encl, struct sgx_va_page *va_page) +{ + encl->page_cnt--; + + if (va_page) { + sgx_encl_free_epc_page(va_page->epc_page); + list_del(&va_page->list); + kfree(va_page); + } +} + +static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs) +{ + struct sgx_epc_page *secs_epc; + struct sgx_va_page *va_page; + struct sgx_pageinfo pginfo; + struct sgx_secinfo secinfo; + unsigned long encl_size; + struct file *backing; + long ret; + + va_page = sgx_encl_grow(encl, true); + if (IS_ERR(va_page)) + return PTR_ERR(va_page); + else if (va_page) + list_add(&va_page->list, &encl->va_pages); + /* else the tail page of the VA page list had free slots. */ + + /* The extra page goes to SECS. */ + encl_size = secs->size + PAGE_SIZE; + + backing = shmem_file_setup("SGX backing", encl_size + (encl_size >> 5), + VM_NORESERVE); + if (IS_ERR(backing)) { + ret = PTR_ERR(backing); + goto err_out_shrink; + } + + encl->backing = backing; + + secs_epc = sgx_alloc_epc_page(&encl->secs, true); + 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_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->secs.type = SGX_PAGE_TYPE_SECS; + 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_encl_free_epc_page(encl->secs.epc_page); + encl->secs.epc_page = NULL; + +err_out_backing: + fput(encl->backing); + encl->backing = NULL; + +err_out_shrink: + sgx_encl_shrink(encl, va_page); + + 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 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; + struct sgx_va_page *va_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(encl_page, true); + if (IS_ERR(epc_page)) { + kfree(encl_page); + return PTR_ERR(epc_page); + } + + va_page = sgx_encl_grow(encl, true); + if (IS_ERR(va_page)) { + ret = PTR_ERR(va_page); + goto err_out_free; + } + + mmap_read_lock(current->mm); + mutex_lock(&encl->lock); + + /* + * Adding to encl->va_pages must be done under encl->lock. Ditto for + * deleting (via sgx_encl_shrink()) in the error path. + */ + if (va_page) + list_add(&va_page->list, &encl->va_pages); + + /* + * 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_page->type = (secinfo->flags & SGX_SECINFO_PAGE_TYPE_MASK) >> 8; + encl->secs_child_cnt++; + + if (flags & SGX_PAGE_MEASURE) { + ret = __sgx_encl_extend(encl, epc_page); + if (ret) + goto err_out; + } + + sgx_mark_page_reclaimable(encl_page->epc_page); + 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: + sgx_encl_shrink(encl, va_page); + mutex_unlock(&encl->lock); + mmap_read_unlock(current->mm); + +err_out_free: + sgx_encl_free_epc_page(epc_page); + kfree(encl_page); + + return ret; +} + +/* + * Ensure user provided offset and length values are valid for + * an enclave. + */ +static int sgx_validate_offset_length(struct sgx_encl *encl, + unsigned long offset, + unsigned long length) +{ + if (!IS_ALIGNED(offset, PAGE_SIZE)) + return -EINVAL; + + if (!length || !IS_ALIGNED(length, PAGE_SIZE)) + return -EINVAL; + + if (offset + length < offset) + return -EINVAL; + + if (offset + length - PAGE_SIZE >= encl->size) + return -EINVAL; + + return 0; +} + +/** + * 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.src, PAGE_SIZE)) + return -EINVAL; + + if (sgx_validate_offset_length(encl, add_arg.offset, add_arg.length)) + 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 = -ERESTARTSYS; + + 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; + 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(); + + sgx_update_lepubkeyhash(mrsigner); + + 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 (encls_faulted(ret)) { + 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; + 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; + + /* + * 'sigstruct' must be on a page boundary and 'token' on a 512 byte + * boundary. kmalloc() will give this alignment when allocating + * PAGE_SIZE bytes. + */ + sigstruct = kmalloc(PAGE_SIZE, GFP_KERNEL); + if (!sigstruct) + return -ENOMEM; + + 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: + kfree(sigstruct); + return ret; +} + +/** + * sgx_ioc_enclave_provision() - handler for %SGX_IOC_ENCLAVE_PROVISION + * @encl: 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; + + if (copy_from_user(¶ms, arg, sizeof(params))) + return -EFAULT; + + return sgx_set_attribute(&encl->attributes_mask, params.fd); +} + +/* + * Ensure enclave is ready for SGX2 functions. Readiness is checked + * by ensuring the hardware supports SGX2 and the enclave is initialized + * and thus able to handle requests to modify pages within it. + */ +static int sgx_ioc_sgx2_ready(struct sgx_encl *encl) +{ + if (!(cpu_feature_enabled(X86_FEATURE_SGX2))) + return -ENODEV; + + if (!test_bit(SGX_ENCL_INITIALIZED, &encl->flags)) + return -EINVAL; + + return 0; +} + +/* + * Some SGX functions require that no cached linear-to-physical address + * mappings are present before they can succeed. Collaborate with + * hardware via ENCLS[ETRACK] to ensure that all cached + * linear-to-physical address mappings belonging to all threads of + * the enclave are cleared. See sgx_encl_cpumask() for details. + * + * Must be called with enclave's mutex held from the time the + * SGX function requiring that no cached linear-to-physical mappings + * are present is executed until this ETRACK flow is complete. + */ +static int sgx_enclave_etrack(struct sgx_encl *encl) +{ + void *epc_virt; + int ret; + + epc_virt = sgx_get_epc_virt_addr(encl->secs.epc_page); + ret = __etrack(epc_virt); + if (ret) { + /* + * ETRACK only fails when there is an OS issue. For + * example, two consecutive ETRACK was sent without + * completed IPI between. + */ + pr_err_once("ETRACK returned %d (0x%x)", ret, ret); + /* + * Send IPIs to kick CPUs out of the enclave and + * try ETRACK again. + */ + on_each_cpu_mask(sgx_encl_cpumask(encl), sgx_ipi_cb, NULL, 1); + ret = __etrack(epc_virt); + if (ret) { + pr_err_once("ETRACK repeat returned %d (0x%x)", + ret, ret); + return -EFAULT; + } + } + on_each_cpu_mask(sgx_encl_cpumask(encl), sgx_ipi_cb, NULL, 1); + + return 0; +} + +/** + * sgx_enclave_restrict_permissions() - Restrict EPCM permissions + * @encl: Enclave to which the pages belong. + * @modp: Checked parameters from user on which pages need modifying and + * their new permissions. + * + * Return: + * - 0: Success. + * - -errno: Otherwise. + */ +static long +sgx_enclave_restrict_permissions(struct sgx_encl *encl, + struct sgx_enclave_restrict_permissions *modp) +{ + struct sgx_encl_page *entry; + struct sgx_secinfo secinfo; + unsigned long addr; + unsigned long c; + void *epc_virt; + int ret; + + memset(&secinfo, 0, sizeof(secinfo)); + secinfo.flags = modp->permissions & SGX_SECINFO_PERMISSION_MASK; + + for (c = 0 ; c < modp->length; c += PAGE_SIZE) { + addr = encl->base + modp->offset + c; + + sgx_reclaim_direct(); + + mutex_lock(&encl->lock); + + entry = sgx_encl_load_page(encl, addr); + if (IS_ERR(entry)) { + ret = PTR_ERR(entry) == -EBUSY ? -EAGAIN : -EFAULT; + goto out_unlock; + } + + /* + * Changing EPCM permissions is only supported on regular + * SGX pages. Attempting this change on other pages will + * result in #PF. + */ + if (entry->type != SGX_PAGE_TYPE_REG) { + ret = -EINVAL; + goto out_unlock; + } + + /* + * Apart from ensuring that read-access remains, do not verify + * the permission bits requested. Kernel has no control over + * how EPCM permissions can be relaxed from within the enclave. + * ENCLS[EMODPR] can only remove existing EPCM permissions, + * attempting to set new permissions will be ignored by the + * hardware. + */ + + /* Change EPCM permissions. */ + epc_virt = sgx_get_epc_virt_addr(entry->epc_page); + ret = __emodpr(&secinfo, epc_virt); + if (encls_faulted(ret)) { + /* + * All possible faults should be avoidable: + * parameters have been checked, will only change + * permissions of a regular page, and no concurrent + * SGX1/SGX2 ENCLS instructions since these + * are protected with mutex. + */ + pr_err_once("EMODPR encountered exception %d\n", + ENCLS_TRAPNR(ret)); + ret = -EFAULT; + goto out_unlock; + } + if (encls_failed(ret)) { + modp->result = ret; + ret = -EFAULT; + goto out_unlock; + } + + ret = sgx_enclave_etrack(encl); + if (ret) { + ret = -EFAULT; + goto out_unlock; + } + + mutex_unlock(&encl->lock); + } + + ret = 0; + goto out; + +out_unlock: + mutex_unlock(&encl->lock); +out: + modp->count = c; + + return ret; +} + +/** + * sgx_ioc_enclave_restrict_permissions() - handler for + * %SGX_IOC_ENCLAVE_RESTRICT_PERMISSIONS + * @encl: an enclave pointer + * @arg: userspace pointer to a &struct sgx_enclave_restrict_permissions + * instance + * + * SGX2 distinguishes between relaxing and restricting the enclave page + * permissions maintained by the hardware (EPCM permissions) of pages + * belonging to an initialized enclave (after SGX_IOC_ENCLAVE_INIT). + * + * EPCM permissions cannot be restricted from within the enclave, the enclave + * requires the kernel to run the privileged level 0 instructions ENCLS[EMODPR] + * and ENCLS[ETRACK]. An attempt to relax EPCM permissions with this call + * will be ignored by the hardware. + * + * Return: + * - 0: Success + * - -errno: Otherwise + */ +static long sgx_ioc_enclave_restrict_permissions(struct sgx_encl *encl, + void __user *arg) +{ + struct sgx_enclave_restrict_permissions params; + long ret; + + ret = sgx_ioc_sgx2_ready(encl); + if (ret) + return ret; + + if (copy_from_user(¶ms, arg, sizeof(params))) + return -EFAULT; + + if (sgx_validate_offset_length(encl, params.offset, params.length)) + return -EINVAL; + + if (params.permissions & ~SGX_SECINFO_PERMISSION_MASK) + return -EINVAL; + + /* + * Fail early if invalid permissions requested to prevent ENCLS[EMODPR] + * from faulting later when the CPU does the same check. + */ + if ((params.permissions & SGX_SECINFO_W) && + !(params.permissions & SGX_SECINFO_R)) + return -EINVAL; + + if (params.result || params.count) + return -EINVAL; + + ret = sgx_enclave_restrict_permissions(encl, ¶ms); + + if (copy_to_user(arg, ¶ms, sizeof(params))) + return -EFAULT; + + return ret; +} + +/** + * sgx_enclave_modify_types() - Modify type of SGX enclave pages + * @encl: Enclave to which the pages belong. + * @modt: Checked parameters from user about which pages need modifying + * and their new page type. + * + * Return: + * - 0: Success + * - -errno: Otherwise + */ +static long sgx_enclave_modify_types(struct sgx_encl *encl, + struct sgx_enclave_modify_types *modt) +{ + unsigned long max_prot_restore; + enum sgx_page_type page_type; + struct sgx_encl_page *entry; + struct sgx_secinfo secinfo; + unsigned long prot; + unsigned long addr; + unsigned long c; + void *epc_virt; + int ret; + + page_type = modt->page_type & SGX_PAGE_TYPE_MASK; + + /* + * The only new page types allowed by hardware are PT_TCS and PT_TRIM. + */ + if (page_type != SGX_PAGE_TYPE_TCS && page_type != SGX_PAGE_TYPE_TRIM) + return -EINVAL; + + memset(&secinfo, 0, sizeof(secinfo)); + + secinfo.flags = page_type << 8; + + for (c = 0 ; c < modt->length; c += PAGE_SIZE) { + addr = encl->base + modt->offset + c; + + sgx_reclaim_direct(); + + mutex_lock(&encl->lock); + + entry = sgx_encl_load_page(encl, addr); + if (IS_ERR(entry)) { + ret = PTR_ERR(entry) == -EBUSY ? -EAGAIN : -EFAULT; + goto out_unlock; + } + + /* + * Borrow the logic from the Intel SDM. Regular pages + * (SGX_PAGE_TYPE_REG) can change type to SGX_PAGE_TYPE_TCS + * or SGX_PAGE_TYPE_TRIM but TCS pages can only be trimmed. + * CET pages not supported yet. + */ + if (!(entry->type == SGX_PAGE_TYPE_REG || + (entry->type == SGX_PAGE_TYPE_TCS && + page_type == SGX_PAGE_TYPE_TRIM))) { + ret = -EINVAL; + goto out_unlock; + } + + max_prot_restore = entry->vm_max_prot_bits; + + /* + * Once a regular page becomes a TCS page it cannot be + * changed back. So the maximum allowed protection reflects + * the TCS page that is always RW from kernel perspective but + * will be inaccessible from within enclave. Before doing + * so, do make sure that the new page type continues to + * respect the originally vetted page permissions. + */ + if (entry->type == SGX_PAGE_TYPE_REG && + page_type == SGX_PAGE_TYPE_TCS) { + if (~entry->vm_max_prot_bits & (VM_READ | VM_WRITE)) { + ret = -EPERM; + goto out_unlock; + } + prot = PROT_READ | PROT_WRITE; + entry->vm_max_prot_bits = calc_vm_prot_bits(prot, 0); + + /* + * Prevent page from being reclaimed while mutex + * is released. + */ + if (sgx_unmark_page_reclaimable(entry->epc_page)) { + ret = -EAGAIN; + goto out_entry_changed; + } + + /* + * Do not keep encl->lock because of dependency on + * mmap_lock acquired in sgx_zap_enclave_ptes(). + */ + mutex_unlock(&encl->lock); + + sgx_zap_enclave_ptes(encl, addr); + + mutex_lock(&encl->lock); + + sgx_mark_page_reclaimable(entry->epc_page); + } + + /* Change EPC type */ + epc_virt = sgx_get_epc_virt_addr(entry->epc_page); + ret = __emodt(&secinfo, epc_virt); + if (encls_faulted(ret)) { + /* + * All possible faults should be avoidable: + * parameters have been checked, will only change + * valid page types, and no concurrent + * SGX1/SGX2 ENCLS instructions since these are + * protected with mutex. + */ + pr_err_once("EMODT encountered exception %d\n", + ENCLS_TRAPNR(ret)); + ret = -EFAULT; + goto out_entry_changed; + } + if (encls_failed(ret)) { + modt->result = ret; + ret = -EFAULT; + goto out_entry_changed; + } + + ret = sgx_enclave_etrack(encl); + if (ret) { + ret = -EFAULT; + goto out_unlock; + } + + entry->type = page_type; + + mutex_unlock(&encl->lock); + } + + ret = 0; + goto out; + +out_entry_changed: + entry->vm_max_prot_bits = max_prot_restore; +out_unlock: + mutex_unlock(&encl->lock); +out: + modt->count = c; + + return ret; +} + +/** + * sgx_ioc_enclave_modify_types() - handler for %SGX_IOC_ENCLAVE_MODIFY_TYPES + * @encl: an enclave pointer + * @arg: userspace pointer to a &struct sgx_enclave_modify_types instance + * + * Ability to change the enclave page type supports the following use cases: + * + * * It is possible to add TCS pages to an enclave by changing the type of + * regular pages (%SGX_PAGE_TYPE_REG) to TCS (%SGX_PAGE_TYPE_TCS) pages. + * With this support the number of threads supported by an initialized + * enclave can be increased dynamically. + * + * * Regular or TCS pages can dynamically be removed from an initialized + * enclave by changing the page type to %SGX_PAGE_TYPE_TRIM. Changing the + * page type to %SGX_PAGE_TYPE_TRIM marks the page for removal with actual + * removal done by handler of %SGX_IOC_ENCLAVE_REMOVE_PAGES ioctl() called + * after ENCLU[EACCEPT] is run on %SGX_PAGE_TYPE_TRIM page from within the + * enclave. + * + * Return: + * - 0: Success + * - -errno: Otherwise + */ +static long sgx_ioc_enclave_modify_types(struct sgx_encl *encl, + void __user *arg) +{ + struct sgx_enclave_modify_types params; + long ret; + + ret = sgx_ioc_sgx2_ready(encl); + if (ret) + return ret; + + if (copy_from_user(¶ms, arg, sizeof(params))) + return -EFAULT; + + if (sgx_validate_offset_length(encl, params.offset, params.length)) + return -EINVAL; + + if (params.page_type & ~SGX_PAGE_TYPE_MASK) + return -EINVAL; + + if (params.result || params.count) + return -EINVAL; + + ret = sgx_enclave_modify_types(encl, ¶ms); + + if (copy_to_user(arg, ¶ms, sizeof(params))) + return -EFAULT; + + return ret; +} + +/** + * sgx_encl_remove_pages() - Remove trimmed pages from SGX enclave + * @encl: Enclave to which the pages belong + * @params: Checked parameters from user on which pages need to be removed + * + * Return: + * - 0: Success. + * - -errno: Otherwise. + */ +static long sgx_encl_remove_pages(struct sgx_encl *encl, + struct sgx_enclave_remove_pages *params) +{ + struct sgx_encl_page *entry; + struct sgx_secinfo secinfo; + unsigned long addr; + unsigned long c; + void *epc_virt; + int ret; + + memset(&secinfo, 0, sizeof(secinfo)); + secinfo.flags = SGX_SECINFO_R | SGX_SECINFO_W | SGX_SECINFO_X; + + for (c = 0 ; c < params->length; c += PAGE_SIZE) { + addr = encl->base + params->offset + c; + + sgx_reclaim_direct(); + + mutex_lock(&encl->lock); + + entry = sgx_encl_load_page(encl, addr); + if (IS_ERR(entry)) { + ret = PTR_ERR(entry) == -EBUSY ? -EAGAIN : -EFAULT; + goto out_unlock; + } + + if (entry->type != SGX_PAGE_TYPE_TRIM) { + ret = -EPERM; + goto out_unlock; + } + + /* + * ENCLS[EMODPR] is a no-op instruction used to inform if + * ENCLU[EACCEPT] was run from within the enclave. If + * ENCLS[EMODPR] is run with RWX on a trimmed page that is + * not yet accepted then it will return + * %SGX_PAGE_NOT_MODIFIABLE, after the trimmed page is + * accepted the instruction will encounter a page fault. + */ + epc_virt = sgx_get_epc_virt_addr(entry->epc_page); + ret = __emodpr(&secinfo, epc_virt); + if (!encls_faulted(ret) || ENCLS_TRAPNR(ret) != X86_TRAP_PF) { + ret = -EPERM; + goto out_unlock; + } + + if (sgx_unmark_page_reclaimable(entry->epc_page)) { + ret = -EBUSY; + goto out_unlock; + } + + /* + * Do not keep encl->lock because of dependency on + * mmap_lock acquired in sgx_zap_enclave_ptes(). + */ + mutex_unlock(&encl->lock); + + sgx_zap_enclave_ptes(encl, addr); + + mutex_lock(&encl->lock); + + sgx_encl_free_epc_page(entry->epc_page); + encl->secs_child_cnt--; + entry->epc_page = NULL; + xa_erase(&encl->page_array, PFN_DOWN(entry->desc)); + sgx_encl_shrink(encl, NULL); + kfree(entry); + + mutex_unlock(&encl->lock); + } + + ret = 0; + goto out; + +out_unlock: + mutex_unlock(&encl->lock); +out: + params->count = c; + + return ret; +} + +/** + * sgx_ioc_enclave_remove_pages() - handler for %SGX_IOC_ENCLAVE_REMOVE_PAGES + * @encl: an enclave pointer + * @arg: userspace pointer to &struct sgx_enclave_remove_pages instance + * + * Final step of the flow removing pages from an initialized enclave. The + * complete flow is: + * + * 1) User changes the type of the pages to be removed to %SGX_PAGE_TYPE_TRIM + * using the %SGX_IOC_ENCLAVE_MODIFY_TYPES ioctl(). + * 2) User approves the page removal by running ENCLU[EACCEPT] from within + * the enclave. + * 3) User initiates actual page removal using the + * %SGX_IOC_ENCLAVE_REMOVE_PAGES ioctl() that is handled here. + * + * First remove any page table entries pointing to the page and then proceed + * with the actual removal of the enclave page and data in support of it. + * + * VA pages are not affected by this removal. It is thus possible that the + * enclave may end up with more VA pages than needed to support all its + * pages. + * + * Return: + * - 0: Success + * - -errno: Otherwise + */ +static long sgx_ioc_enclave_remove_pages(struct sgx_encl *encl, + void __user *arg) +{ + struct sgx_enclave_remove_pages params; + long ret; + + ret = sgx_ioc_sgx2_ready(encl); + if (ret) + return ret; + + if (copy_from_user(¶ms, arg, sizeof(params))) + return -EFAULT; + + if (sgx_validate_offset_length(encl, params.offset, params.length)) + return -EINVAL; + + if (params.count) + return -EINVAL; + + ret = sgx_encl_remove_pages(encl, ¶ms); + + if (copy_to_user(arg, ¶ms, sizeof(params))) + return -EFAULT; + + return ret; +} + +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; + case SGX_IOC_ENCLAVE_RESTRICT_PERMISSIONS: + ret = sgx_ioc_enclave_restrict_permissions(encl, + (void __user *)arg); + break; + case SGX_IOC_ENCLAVE_MODIFY_TYPES: + ret = sgx_ioc_enclave_modify_types(encl, (void __user *)arg); + break; + case SGX_IOC_ENCLAVE_REMOVE_PAGES: + ret = sgx_ioc_enclave_remove_pages(encl, (void __user *)arg); + break; + default: + ret = -ENOIOCTLCMD; + break; + } + + clear_bit(SGX_ENCL_IOCTL, &encl->flags); + return ret; +} |