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=-12.8 required=3.0 tests=BAYES_00, 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 1E216C47428 for ; Tue, 29 Sep 2020 21:02:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C767A20757 for ; Tue, 29 Sep 2020 21:02:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729682AbgI2VCB (ORCPT ); Tue, 29 Sep 2020 17:02:01 -0400 Received: from mga02.intel.com ([134.134.136.20]:60573 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728706AbgI2VBv (ORCPT ); Tue, 29 Sep 2020 17:01:51 -0400 IronPort-SDR: YfTyMfrbguWZmnCuRGV4SOXMdINRAy6uJ0kLele/ysjaM9MC5uf8lFGWn6Z8yvDP96OnAZEzFp ofY45jg1Aseg== X-IronPort-AV: E=McAfee;i="6000,8403,9759"; a="149947658" X-IronPort-AV: E=Sophos;i="5.77,319,1596524400"; d="scan'208";a="149947658" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Sep 2020 14:01:23 -0700 IronPort-SDR: xLvnenyORWIZmPprRiCX1izRF7kqy5wrzHxD/KHxNIyKhTIns+BNG/UChh/Lz0XXN/pzrKHNCj 1Xgig24QjiHw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,319,1596524400"; d="scan'208";a="514024813" Received: from chang-linux-3.sc.intel.com ([172.25.66.175]) by fmsmga006.fm.intel.com with ESMTP; 29 Sep 2020 14:01:22 -0700 From: "Chang S. Bae" To: tglx@linutronix.de, mingo@kernel.org, bp@suse.de, luto@kernel.org, x86@kernel.org Cc: len.brown@intel.com, dave.hansen@intel.com, hjl.tools@gmail.com, Dave.Martin@arm.com, mpe@ellerman.id.au, tony.luck@intel.com, ravi.v.shankar@intel.com, libc-alpha@sourceware.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, chang.seok.bae@intel.com, Fenghua Yu Subject: [RFC PATCH 2/4] x86/elf: Support a new ELF aux vector AT_MINSIGSTKSZ Date: Tue, 29 Sep 2020 13:57:44 -0700 Message-Id: <20200929205746.6763-3-chang.seok.bae@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200929205746.6763-1-chang.seok.bae@intel.com> References: <20200929205746.6763-1-chang.seok.bae@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Historically, signal.h defines MINSIGSTKSZ (2KB) and SIGSTKSZ (8KB), for use by all architectures with sigaltstack(2). Over time, the hardware state size grew, but these constants did not evolve. Today, literal use of these constants on several architectures may result in signal stack overflow, and thus user data corruption. A few years ago, the ARM team addressed this issue by establishing getauxval(AT_MINSIGSTKSZ), such that the kernel can supply at runtime value that is an appropriate replacement on the current and future hardware. Add getauxval(AT_MINSIGSTKSZ) support to x86, analogous to the support added for ARM in commit 94b07c1f8c39 ("arm64: signal: Report signal frame size to userspace via auxv"). Reported-by: Florian Weimer Fixes: c2bc11f10a39 ("x86, AVX-512: Enable AVX-512 States Context Switch") Signed-off-by: Chang S. Bae Reviewed-by: Len Brown Cc: H.J. Lu Cc: Fenghua Yu Cc: Dave Martin Cc: Michael Ellerman Cc: x86@kernel.org Cc: libc-alpha@sourceware.org Cc: linux-arch@vger.kernel.org Cc: linux-api@vger.kernel.org Cc: linux-kernel@vger.kernel.org Link: https://bugzilla.kernel.org/show_bug.cgi?id=153531 --- arch/x86/include/asm/elf.h | 4 ++++ arch/x86/include/uapi/asm/auxvec.h | 6 ++++-- arch/x86/kernel/signal.c | 5 +++++ 3 files changed, 13 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h index b9a5d488f1a5..044b024abea1 100644 --- a/arch/x86/include/asm/elf.h +++ b/arch/x86/include/asm/elf.h @@ -311,6 +311,7 @@ do { \ NEW_AUX_ENT(AT_SYSINFO, VDSO_ENTRY); \ NEW_AUX_ENT(AT_SYSINFO_EHDR, VDSO_CURRENT_BASE); \ } \ + NEW_AUX_ENT(AT_MINSIGSTKSZ, get_sigframe_size()); \ } while (0) /* @@ -327,6 +328,7 @@ extern unsigned long task_size_32bit(void); extern unsigned long task_size_64bit(int full_addr_space); extern unsigned long get_mmap_base(int is_legacy); extern bool mmap_address_hint_valid(unsigned long addr, unsigned long len); +extern unsigned long get_sigframe_size(void); #ifdef CONFIG_X86_32 @@ -348,6 +350,7 @@ do { \ if (vdso64_enabled) \ NEW_AUX_ENT(AT_SYSINFO_EHDR, \ (unsigned long __force)current->mm->context.vdso); \ + NEW_AUX_ENT(AT_MINSIGSTKSZ, get_sigframe_size()); \ } while (0) /* As a historical oddity, the x32 and x86_64 vDSOs are controlled together. */ @@ -356,6 +359,7 @@ do { \ if (vdso64_enabled) \ NEW_AUX_ENT(AT_SYSINFO_EHDR, \ (unsigned long __force)current->mm->context.vdso); \ + NEW_AUX_ENT(AT_MINSIGSTKSZ, get_sigframe_size()); \ } while (0) #define AT_SYSINFO 32 diff --git a/arch/x86/include/uapi/asm/auxvec.h b/arch/x86/include/uapi/asm/auxvec.h index 580e3c567046..edd7808060e6 100644 --- a/arch/x86/include/uapi/asm/auxvec.h +++ b/arch/x86/include/uapi/asm/auxvec.h @@ -10,11 +10,13 @@ #endif #define AT_SYSINFO_EHDR 33 +#define AT_MINSIGSTKSZ 51 + /* entries in ARCH_DLINFO: */ #if defined(CONFIG_IA32_EMULATION) || !defined(CONFIG_X86_64) -# define AT_VECTOR_SIZE_ARCH 2 +# define AT_VECTOR_SIZE_ARCH 3 #else /* else it's non-compat x86-64 */ -# define AT_VECTOR_SIZE_ARCH 1 +# define AT_VECTOR_SIZE_ARCH 2 #endif #endif /* _ASM_X86_AUXVEC_H */ diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index 239a0b23a4b0..2a313d34ec49 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -708,6 +708,11 @@ void __init init_sigframe_size(void) max_frame_size += fpu__get_fpstate_sigframe_size() + MAX_XSAVE_PADDING; } +unsigned long get_sigframe_size(void) +{ + return max_frame_size; +} + static inline int is_ia32_compat_frame(struct ksignal *ksig) { return IS_ENABLED(CONFIG_IA32_EMULATION) && -- 2.17.1