From patchwork Tue Oct 25 00:17:11 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Kirill A. Shutemov" X-Patchwork-Id: 13018309 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id B2AFBC38A2D for ; Tue, 25 Oct 2022 00:17:49 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2ED6380007; Mon, 24 Oct 2022 20:17:46 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id F3FA88000D; Mon, 24 Oct 2022 20:17:45 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C326C8000B; Mon, 24 Oct 2022 20:17:45 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 81F708000C for ; Mon, 24 Oct 2022 20:17:45 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 56EF7403CD for ; Tue, 25 Oct 2022 00:17:45 +0000 (UTC) X-FDA: 80057558490.06.AF9057C Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by imf11.hostedemail.com (Postfix) with ESMTP id 4725B40019 for ; Tue, 25 Oct 2022 00:17:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1666657063; x=1698193063; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=URl4+yXuTZU7i5eHga9UDkYb72zi7S2whgUd+vZqeAk=; b=C7GbbsrYYYu2DMjqF0JExrd90TCXNpbrkrxnXFcEe9tdFWpZcjTu5WX5 1m5v9tzAW/BQmyc3C34mg5kWh8SZ2dYJJxQKDS37Guu4oK1cW1tilXI+Q PwUIZNzKntpO7F9pDJNOI9sqJm55hZQUuHLOlYmfugyZGAN4FG5OeRQTZ HrQs/JfSmFjznnvz2CReCRuikR0XHaFuCVX5A2CG1sO8qXhl5KpSPUkDV f/rb8CG22UueOR2cTftLYLrlatxym1L3+scpe50y9E5LtwizJIavxpvTa tqBm9XEc73FzloEg3KSMpD3aCaLKuhI5CPIcEz/b1PJO4NzpX8+vRjvwP g==; X-IronPort-AV: E=McAfee;i="6500,9779,10510"; a="308644673" X-IronPort-AV: E=Sophos;i="5.95,210,1661842800"; d="scan'208";a="308644673" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Oct 2022 17:17:41 -0700 X-IronPort-AV: E=McAfee;i="6500,9779,10510"; a="631447756" X-IronPort-AV: E=Sophos;i="5.95,210,1661842800"; d="scan'208";a="631447756" Received: from ghoyler-mobl.ger.corp.intel.com (HELO box.shutemov.name) ([10.249.39.118]) by orsmga002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Oct 2022 17:17:35 -0700 Received: by box.shutemov.name (Postfix, from userid 1000) id D1AA81095BA; Tue, 25 Oct 2022 03:17:25 +0300 (+03) From: "Kirill A. Shutemov" To: Dave Hansen , Andy Lutomirski , Peter Zijlstra Cc: x86@kernel.org, Kostya Serebryany , Andrey Ryabinin , Andrey Konovalov , Alexander Potapenko , Taras Madan , Dmitry Vyukov , "H . J . Lu" , Andi Kleen , Rick Edgecombe , Bharata B Rao , Jacob Pan , Ashok Raj , linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: [PATCHv11 05/16] x86/uaccess: Provide untagged_addr() and remove tags before address check Date: Tue, 25 Oct 2022 03:17:11 +0300 Message-Id: <20221025001722.17466-6-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.38.0 In-Reply-To: <20221025001722.17466-1-kirill.shutemov@linux.intel.com> References: <20221025001722.17466-1-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1666657063; a=rsa-sha256; cv=none; b=Yn1Fl+HbgaH/KrnLddZmRz/FEDowZ9aFrRbTQrnCvszCzrkwWkbaIEZ/dPvtBEueVgLddG ZCr5DiqJFnfHWU8TFvG40JE1iE9kt9oPeohalYTeiZXVOnFD/IbXmSS9xwNu3ifoEygK2f xSxM64OLQHkk85JQU6o+K+cqRieAmZA= ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=C7GbbsrY; dmarc=fail reason="No valid SPF" header.from=intel.com (policy=none); spf=none (imf11.hostedemail.com: domain of kirill.shutemov@linux.intel.com has no SPF policy when checking 134.134.136.24) smtp.mailfrom=kirill.shutemov@linux.intel.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1666657063; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=DbV8cHAt/2UaBv88Klfmogq3Zr74tZzoImyK7jUvyRo=; b=t01Cgquoe97hi8CLpDhjSJbzubsyRDH+fSdNWxfu1+/iZ0qcOJsqTC/b230yeQ0a+/bJ5q IQNgdlKuSK2Wcv5VR+MMw5e5NQasZnu10QJySbx7ZTF/kYdTkxe0iG5XE3l9etEtTNUMt0 6rz+AdSJwgPUg2bqsvYUSIVQ3iE610M= X-Rspamd-Queue-Id: 4725B40019 Authentication-Results: imf11.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=C7GbbsrY; dmarc=fail reason="No valid SPF" header.from=intel.com (policy=none); spf=none (imf11.hostedemail.com: domain of kirill.shutemov@linux.intel.com has no SPF policy when checking 134.134.136.24) smtp.mailfrom=kirill.shutemov@linux.intel.com X-Rspamd-Server: rspam12 X-Rspam-User: X-Stat-Signature: kywg3i7ic7e8aqs4pcrtnjk95hy8xitr X-HE-Tag: 1666657063-252479 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: untagged_addr() is a helper used by the core-mm to strip tag bits and get the address to the canonical shape. In only handles userspace addresses. The untagging mask is stored in mmu_context and will be set on enabling LAM for the process. The tags must not be included into check whether it's okay to access the userspace address. Strip tags in access_ok(). get_user() and put_user() don't use access_ok(), but check access against TASK_SIZE directly in assembly. Strip tags, before calling into the assembly helper. Signed-off-by: Kirill A. Shutemov Tested-by: Alexander Potapenko Acked-by: Peter Zijlstra (Intel) Acked-by: Andy Lutomirski --- arch/x86/include/asm/mmu.h | 3 +++ arch/x86/include/asm/mmu_context.h | 11 ++++++++ arch/x86/include/asm/uaccess.h | 42 +++++++++++++++++++++++++++--- arch/x86/kernel/process.c | 3 +++ 4 files changed, 56 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/mmu.h b/arch/x86/include/asm/mmu.h index 002889ca8978..2fdb390040b5 100644 --- a/arch/x86/include/asm/mmu.h +++ b/arch/x86/include/asm/mmu.h @@ -43,6 +43,9 @@ typedef struct { /* Active LAM mode: X86_CR3_LAM_U48 or X86_CR3_LAM_U57 or 0 (disabled) */ unsigned long lam_cr3_mask; + + /* Significant bits of the virtual address. Excludes tag bits. */ + u64 untag_mask; #endif struct mutex lock; diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h index 69c943b2ae90..5bd3d46685dc 100644 --- a/arch/x86/include/asm/mmu_context.h +++ b/arch/x86/include/asm/mmu_context.h @@ -100,6 +100,12 @@ static inline unsigned long mm_lam_cr3_mask(struct mm_struct *mm) static inline void dup_lam(struct mm_struct *oldmm, struct mm_struct *mm) { mm->context.lam_cr3_mask = oldmm->context.lam_cr3_mask; + mm->context.untag_mask = oldmm->context.untag_mask; +} + +static inline void mm_reset_untag_mask(struct mm_struct *mm) +{ + mm->context.untag_mask = -1UL; } #else @@ -112,6 +118,10 @@ static inline unsigned long mm_lam_cr3_mask(struct mm_struct *mm) static inline void dup_lam(struct mm_struct *oldmm, struct mm_struct *mm) { } + +static inline void mm_reset_untag_mask(struct mm_struct *mm) +{ +} #endif #define enter_lazy_tlb enter_lazy_tlb @@ -138,6 +148,7 @@ static inline int init_new_context(struct task_struct *tsk, mm->context.execute_only_pkey = -1; } #endif + mm_reset_untag_mask(mm); init_new_context_ldt(mm); return 0; } diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index 8bc614cfe21b..c6062c07ccd2 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -7,6 +7,7 @@ #include #include #include +#include #include #include #include @@ -21,6 +22,30 @@ static inline bool pagefault_disabled(void); # define WARN_ON_IN_IRQ() #endif +#ifdef CONFIG_X86_64 +/* + * Mask out tag bits from the address. + * + * Magic with the 'sign' allows to untag userspace pointer without any branches + * while leaving kernel addresses intact. + */ +#define untagged_addr(mm, addr) ({ \ + u64 __addr = (__force u64)(addr); \ + s64 sign = (s64)__addr >> 63; \ + __addr &= (mm)->context.untag_mask | sign; \ + (__force __typeof__(addr))__addr; \ +}) + +#define untagged_ptr(mm, ptr) ({ \ + u64 __ptrval = (__force u64)(ptr); \ + __ptrval = untagged_addr(mm, __ptrval); \ + (__force __typeof__(*(ptr)) *)__ptrval; \ +}) +#else +#define untagged_addr(mm, addr) (addr) +#define untagged_ptr(mm, ptr) (ptr) +#endif + /** * access_ok - Checks if a user space pointer is valid * @addr: User space pointer to start of block to check @@ -41,7 +66,7 @@ static inline bool pagefault_disabled(void); #define access_ok(addr, size) \ ({ \ WARN_ON_IN_IRQ(); \ - likely(__access_ok(addr, size)); \ + likely(__access_ok(untagged_addr(current->mm, addr), size)); \ }) #include @@ -127,7 +152,13 @@ extern int __get_user_bad(void); * Return: zero on success, or -EFAULT on error. * On error, the variable @x is set to zero. */ -#define get_user(x,ptr) ({ might_fault(); do_get_user_call(get_user,x,ptr); }) +#define get_user(x,ptr) \ +({ \ + __typeof__(*(ptr)) __user *__ptr_clean; \ + __ptr_clean = untagged_ptr(current->mm, ptr); \ + might_fault(); \ + do_get_user_call(get_user,x,__ptr_clean); \ +}) /** * __get_user - Get a simple variable from user space, with less checking. @@ -227,7 +258,12 @@ extern void __put_user_nocheck_8(void); * * Return: zero on success, or -EFAULT on error. */ -#define put_user(x, ptr) ({ might_fault(); do_put_user_call(put_user,x,ptr); }) +#define put_user(x, ptr) ({ \ + __typeof__(*(ptr)) __user *__ptr_clean; \ + __ptr_clean = untagged_ptr(current->mm, ptr); \ + might_fault(); \ + do_put_user_call(put_user,x,__ptr_clean); \ +}) /** * __put_user - Write a simple value into user space, with less checking. diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index c21b7347a26d..d1e83ba21130 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -47,6 +47,7 @@ #include #include #include +#include #include "process.h" @@ -367,6 +368,8 @@ void arch_setup_new_exec(void) task_clear_spec_ssb_noexec(current); speculation_ctrl_update(read_thread_flags()); } + + mm_reset_untag_mask(current->mm); } #ifdef CONFIG_X86_IOPL_IOPERM