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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /arch/x86/kernel/cpu/sgx/ioctl.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/x86/kernel/cpu/sgx/ioctl.c')
-rw-r--r--arch/x86/kernel/cpu/sgx/ioctl.c1263
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(&params, 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(&params, 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, &params);
+
+ if (copy_to_user(arg, &params, 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(&params, 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, &params);
+
+ if (copy_to_user(arg, &params, 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(&params, 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, &params);
+
+ if (copy_to_user(arg, &params, 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;
+}