From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C7299C32750 for ; Tue, 13 Aug 2019 21:03:47 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 82F202070D for ; Tue, 13 Aug 2019 21:03:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 82F202070D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 3B7096B027F; Tue, 13 Aug 2019 17:03:12 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2EFE36B0280; Tue, 13 Aug 2019 17:03:12 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 193D56B0281; Tue, 13 Aug 2019 17:03:12 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0056.hostedemail.com [216.40.44.56]) by kanga.kvack.org (Postfix) with ESMTP id DE1F16B027F for ; Tue, 13 Aug 2019 17:03:11 -0400 (EDT) Received: from smtpin14.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id 80B846121 for ; Tue, 13 Aug 2019 21:03:11 +0000 (UTC) X-FDA: 75818629782.14.queen56_1bbfa1a516c2e X-HE-Tag: queen56_1bbfa1a516c2e X-Filterd-Recvd-Size: 9443 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by imf22.hostedemail.com (Postfix) with ESMTP for ; Tue, 13 Aug 2019 21:03:10 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 13 Aug 2019 14:03:10 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,382,1559545200"; d="scan'208";a="187901555" Received: from yyu32-desk1.sc.intel.com ([10.144.153.205]) by orsmga002.jf.intel.com with ESMTP; 13 Aug 2019 14:03:08 -0700 From: Yu-cheng Yu To: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin Cc: Yu-cheng Yu Subject: [PATCH v8 26/27] x86/cet/shstk: Add arch_prctl functions for Shadow Stack Date: Tue, 13 Aug 2019 13:52:24 -0700 Message-Id: <20190813205225.12032-27-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190813205225.12032-1-yu-cheng.yu@intel.com> References: <20190813205225.12032-1-yu-cheng.yu@intel.com> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: arch_prctl(ARCH_X86_CET_STATUS, unsigned long *addr) Return CET feature status. The parameter 'addr' is a pointer to a user buffer. On returning to the caller, the kernel fills the following information: *addr = SHSTK/IBT status *(addr + 1) = SHSTK base address *(addr + 2) = SHSTK size arch_prctl(ARCH_X86_CET_DISABLE, unsigned long features) Disable CET features specified in 'features'. Return -EPERM if CET is locked. arch_prctl(ARCH_X86_CET_LOCK) Lock in CET feature. arch_prctl(ARCH_X86_CET_ALLOC_SHSTK, unsigned long *addr) Allocate a new SHSTK. The parameter 'addr' is a pointer to a user buffer and indicates the desired SHSTK size to allocate. On returning to the caller the buffer contains the address of the new SHSTK. There is no CET enabling arch_prctl function. By design, CET is enabled automatically if the binary and the system can support it. The parameters passed are always unsigned 64-bit. When an ia32 application passing pointers, it should only use the lower 32 bits. Signed-off-by: Yu-cheng Yu --- arch/x86/include/asm/cet.h | 5 ++ arch/x86/include/uapi/asm/prctl.h | 5 ++ arch/x86/kernel/Makefile | 2 +- arch/x86/kernel/cet.c | 29 +++++++++++ arch/x86/kernel/cet_prctl.c | 85 +++++++++++++++++++++++++++++++ arch/x86/kernel/process.c | 4 +- 6 files changed, 127 insertions(+), 3 deletions(-) create mode 100644 arch/x86/kernel/cet_prctl.c diff --git a/arch/x86/include/asm/cet.h b/arch/x86/include/asm/cet.h index 52c506a68848..2df357dffd24 100644 --- a/arch/x86/include/asm/cet.h +++ b/arch/x86/include/asm/cet.h @@ -14,19 +14,24 @@ struct sc_ext; struct cet_status { unsigned long shstk_base; unsigned long shstk_size; + unsigned int locked:1; unsigned int shstk_enabled:1; }; #ifdef CONFIG_X86_INTEL_CET +int prctl_cet(int option, unsigned long arg2); int cet_setup_shstk(void); int cet_setup_thread_shstk(struct task_struct *p); +int cet_alloc_shstk(unsigned long *arg); void cet_disable_shstk(void); void cet_disable_free_shstk(struct task_struct *p); int cet_restore_signal(bool ia32, struct sc_ext *sc); int cet_setup_signal(bool ia32, unsigned long rstor, struct sc_ext *sc); #else +static inline int prctl_cet(int option, unsigned long arg2) { return -EINVAL; } static inline int cet_setup_shstk(void) { return -EINVAL; } static inline int cet_setup_thread_shstk(struct task_struct *p) { return 0; } +static inline int cet_alloc_shstk(unsigned long *arg) { return -EINVAL; } static inline void cet_disable_shstk(void) {} static inline void cet_disable_free_shstk(struct task_struct *p) {} static inline int cet_restore_signal(bool ia32, struct sc_ext *sc) { return -EINVAL; } diff --git a/arch/x86/include/uapi/asm/prctl.h b/arch/x86/include/uapi/asm/prctl.h index 5a6aac9fa41f..d962f0ec9ccf 100644 --- a/arch/x86/include/uapi/asm/prctl.h +++ b/arch/x86/include/uapi/asm/prctl.h @@ -14,4 +14,9 @@ #define ARCH_MAP_VDSO_32 0x2002 #define ARCH_MAP_VDSO_64 0x2003 +#define ARCH_X86_CET_STATUS 0x3001 +#define ARCH_X86_CET_DISABLE 0x3002 +#define ARCH_X86_CET_LOCK 0x3003 +#define ARCH_X86_CET_ALLOC_SHSTK 0x3004 + #endif /* _ASM_X86_PRCTL_H */ diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index c7d918a87cac..311829335521 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -140,7 +140,7 @@ obj-$(CONFIG_UNWINDER_ORC) += unwind_orc.o obj-$(CONFIG_UNWINDER_FRAME_POINTER) += unwind_frame.o obj-$(CONFIG_UNWINDER_GUESS) += unwind_guess.o -obj-$(CONFIG_X86_INTEL_CET) += cet.o +obj-$(CONFIG_X86_INTEL_CET) += cet.o cet_prctl.o ### # 64 bit specific files diff --git a/arch/x86/kernel/cet.c b/arch/x86/kernel/cet.c index e876150178ca..e4e20d6ab07b 100644 --- a/arch/x86/kernel/cet.c +++ b/arch/x86/kernel/cet.c @@ -127,6 +127,35 @@ static int create_rstor_token(bool ia32, unsigned long ssp, return 0; } +int cet_alloc_shstk(unsigned long *arg) +{ + unsigned long len = *arg; + unsigned long addr; + unsigned long token; + unsigned long ssp; + + addr = do_mmap_locked(NULL, 0, len, PROT_READ, + MAP_ANONYMOUS | MAP_PRIVATE, VM_SHSTK, NULL); + if (addr >= TASK_SIZE_MAX) + return -ENOMEM; + + /* Restore token is 8 bytes and aligned to 8 bytes */ + ssp = addr + len; + token = ssp; + + if (!in_ia32_syscall()) + token |= TOKEN_MODE_64; + ssp -= 8; + + if (write_user_shstk_64(ssp, token)) { + vm_munmap(addr, len); + return -EINVAL; + } + + *arg = addr; + return 0; +} + int cet_setup_shstk(void) { unsigned long addr, size; diff --git a/arch/x86/kernel/cet_prctl.c b/arch/x86/kernel/cet_prctl.c new file mode 100644 index 000000000000..9c9d4262b07e --- /dev/null +++ b/arch/x86/kernel/cet_prctl.c @@ -0,0 +1,85 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* See Documentation/x86/intel_cet.rst. */ + +static int handle_get_status(unsigned long arg2) +{ + unsigned int features = 0; + unsigned long shstk_base, shstk_size; + unsigned long buf[3]; + + if (current->thread.cet.shstk_enabled) + features |= GNU_PROPERTY_X86_FEATURE_1_SHSTK; + + shstk_base = current->thread.cet.shstk_base; + shstk_size = current->thread.cet.shstk_size; + + buf[0] = (unsigned long)features; + buf[1] = shstk_base; + buf[2] = shstk_size; + return copy_to_user((unsigned long __user *)arg2, buf, + sizeof(buf)); +} + +static int handle_alloc_shstk(unsigned long arg2) +{ + int err = 0; + unsigned long arg; + unsigned long addr = 0; + unsigned long size = 0; + + if (get_user(arg, (unsigned long __user *)arg2)) + return -EFAULT; + + size = arg; + err = cet_alloc_shstk(&arg); + if (err) + return err; + + addr = arg; + if (put_user(addr, (unsigned long __user *)arg2)) { + vm_munmap(addr, size); + return -EFAULT; + } + + return 0; +} + +int prctl_cet(int option, unsigned long arg2) +{ + if (!cpu_x86_cet_enabled()) + return -EINVAL; + + switch (option) { + case ARCH_X86_CET_STATUS: + return handle_get_status(arg2); + + case ARCH_X86_CET_DISABLE: + if (current->thread.cet.locked) + return -EPERM; + if (arg2 & GNU_PROPERTY_X86_FEATURE_1_SHSTK) + cet_disable_free_shstk(current); + + return 0; + + case ARCH_X86_CET_LOCK: + current->thread.cet.locked = 1; + return 0; + + case ARCH_X86_CET_ALLOC_SHSTK: + return handle_alloc_shstk(arg2); + + default: + return -EINVAL; + } +} diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 58b1c52b38b5..e0090f2790df 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -873,7 +873,7 @@ long do_arch_prctl_common(struct task_struct *task, int option, return get_cpuid_mode(); case ARCH_SET_CPUID: return set_cpuid_mode(task, cpuid_enabled); + default: + return prctl_cet(option, cpuid_enabled); } - - return -EINVAL; } -- 2.17.1