[v38,13/24] x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES

Message ID	20200915110522.893152-14-jarkko.sakkinen@linux.intel.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <SRS0=2CfR=CY=vger.kernel.org=linux-sgx-owner@kernel.org> From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> To: x86@kernel.org, linux-sgx@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>, Jethro Beekman <jethro@fortanix.com>, Haitao Huang <haitao.huang@linux.intel.com>, Chunyang Hui <sanqian.hcy@antfin.com>, Jordan Hand <jorhand@linux.microsoft.com>, Nathaniel McCallum <npmccallum@redhat.com>, Seth Moore <sethmo@google.com>, Darren Kenny <darren.kenny@oracle.com>, Sean Christopherson <sean.j.christopherson@intel.com>, Suresh Siddha <suresh.b.siddha@intel.com>, akpm@linux-foundation.org, andriy.shevchenko@linux.intel.com, asapek@google.com, bp@alien8.de, cedric.xing@intel.com, chenalexchen@google.com, conradparker@google.com, cyhanish@google.com, dave.hansen@intel.com, haitao.huang@intel.com, josh@joshtriplett.org, kai.huang@intel.com, kai.svahn@intel.com, kmoy@google.com, ludloff@google.com, luto@kernel.org, nhorman@redhat.com, puiterwijk@redhat.com, rientjes@google.com, tglx@linutronix.de, yaozhangx@google.com Subject: [PATCH v38 13/24] x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES Date: Tue, 15 Sep 2020 14:05:11 +0300 Message-Id: <20200915110522.893152-14-jarkko.sakkinen@linux.intel.com> In-Reply-To: <20200915110522.893152-1-jarkko.sakkinen@linux.intel.com> References: <20200915110522.893152-1-jarkko.sakkinen@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-sgx-owner@vger.kernel.org Precedence: bulk
Series	Intel SGX foundations \| expand [v38,00/24] Intel SGX foundations [v38,01/24] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits [v38,02/24] x86/cpufeatures: x86/msr: Add Intel SGX Launch Control hardware bits [v38,03/24] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX [v38,04/24] x86/sgx: Add SGX microarchitectural data structures [v38,05/24] x86/sgx: Add wrappers for ENCLS leaf functions [v38,06/24] x86/cpu/intel: Detect SGX support [v38,07/24] x86/cpu/intel: Add nosgx kernel parameter [v38,08/24] x86/sgx: Initialize metadata for Enclave Page Cache (EPC) sections [v38,09/24] x86/sgx: Add __sgx_alloc_epc_page() and sgx_free_epc_page() [v38,10/24] mm: Add vm_ops->mprotect() [v38,11/24] x86/sgx: Add SGX enclave driver [v38,12/24] x86/sgx: Add SGX_IOC_ENCLAVE_CREATE [v38,13/24] x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES [v38,14/24] x86/sgx: Add SGX_IOC_ENCLAVE_INIT [v38,15/24] x86/sgx: Enable provisioning for remote attestation [v38,16/24] x86/sgx: Add a page reclaimer [v38,17/24] x86/sgx: ptrace() support for the SGX driver [v38,18/24] x86/vdso: Add support for exception fixup in vDSO functions [v38,19/24] x86/fault: Add helper function to sanitize error code [v38,20/24] x86/traps: Attempt to fixup exceptions in vDSO before signaling [v38,21/24] x86/vdso: Implement a vDSO for Intel SGX enclave call [v38,22/24] selftests/x86: Add a selftest for SGX [v38,23/24] docs: x86/sgx: Document SGX micro architecture and kernel internals [v38,24/24] x86/sgx: Update MAINTAINERS

diff --git a/arch/x86/include/uapi/asm/sgx.h b/arch/x86/include/uapi/asm/sgx.h index c75b375f3770..c42a2ad3ca0b 100644 --- a/arch/x86/include/uapi/asm/sgx.h +++ b/arch/x86/include/uapi/asm/sgx.h @@ -8,10 +8,21 @@ #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) /** * struct sgx_enclave_create - parameter structure for the @@ -22,4 +33,21 @@ 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; +}; + #endif /* _UAPI_ASM_X86_SGX_H */ diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c index 352a3c461812..202680a06c17 100644 --- a/arch/x86/kernel/cpu/sgx/ioctl.c +++ b/arch/x86/kernel/cpu/sgx/ioctl.c @@ -191,6 +191,297 @@ static long sgx_ioc_enclave_create(struct sgx_encl *encl, void __user *arg) 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; + + /* 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_get_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_get_epc_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) +{ + int ret; + int i; + + for (i = 0; i < 16; i++) { + ret = __eextend(sgx_get_epc_addr(encl->secs.epc_page), + sgx_get_epc_addr(epc_page) + (i * 0x100)); + 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); + + /* + * Destroy enclave on ENCLS failure as this means that EPC has been + * invalidated. + */ + if (ret == -EIO) { + mutex_lock(&encl->lock); + sgx_encl_destroy(encl); + mutex_unlock(&encl->lock); + } + + 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. + * + * If ENCLS opcode fails, that effectively means that EPC has been invalidated. + * When this happens the enclave is destroyed and -EIO is returned to the + * caller. + * + * Return: + * length of the data processed on success, + * -EACCES if an executable source page is located in a noexec partition, + * -EIO if either ENCLS[EADD] or ENCLS[EEXTEND] fails + * -errno otherwise + */ +static long sgx_ioc_enclave_add_pages(struct sgx_encl *encl, void __user *arg) +{ + struct sgx_enclave_add_pages addp; + struct sgx_secinfo secinfo; + unsigned long c; + int ret; + + if ((atomic_read(&encl->flags) & SGX_ENCL_INITIALIZED) || + !(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 (c = 0 ; c < addp.length; c += PAGE_SIZE) { + if (signal_pending(current)) { + if (!c) + ret = -EINTR; + + break; + } + + if (c == SGX_MAX_ADD_PAGES_LENGTH) + break; + + if (need_resched()) + cond_resched(); + + ret = sgx_encl_add_page(encl, addp.src + c, addp.offset + c, + &secinfo, addp.flags); + if (ret) + break; + } + + if (ret) + return ret; + + return c; +} + long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg) { struct sgx_encl *encl = filep->private_data; @@ -209,6 +500,9 @@ long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg) 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; default: ret = -ENOIOCTLCMD; break; diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h index fce756c3434b..8d126070db1e 100644 --- a/arch/x86/kernel/cpu/sgx/sgx.h +++ b/arch/x86/kernel/cpu/sgx/sgx.h @@ -34,6 +34,7 @@ struct sgx_epc_section { #define SGX_EPC_SECTION_MASK GENMASK(7, 0) #define SGX_MAX_EPC_SECTIONS (SGX_EPC_SECTION_MASK + 1) +#define SGX_MAX_ADD_PAGES_LENGTH 0x100000 extern struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];

[v38,13/24] x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES

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