From patchwork Tue Jul 12 23:13:20 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: 12915800 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 1AA9AC43334 for ; Tue, 12 Jul 2022 23:13:36 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DA4069400E0; Tue, 12 Jul 2022 19:13:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D2CBA9400DD; Tue, 12 Jul 2022 19:13:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 90E1E9400E0; Tue, 12 Jul 2022 19:13:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 7FF679400DD for ; Tue, 12 Jul 2022 19:13:31 -0400 (EDT) Received: from smtpin29.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 5B29C35126 for ; Tue, 12 Jul 2022 23:13:31 +0000 (UTC) X-FDA: 79680001422.29.E50FE2B Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by imf03.hostedemail.com (Postfix) with ESMTP id 7D8EC20039 for ; Tue, 12 Jul 2022 23:13:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1657667610; x=1689203610; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=FNDoAfmeIi8uLbuI0UIqM3X0guL9pMr/mCnJr0E5bVU=; b=nWngtr4y64mzfPSW7oXzu0Ybn/Sy0rkzdal/11RGVMeRZzIvt5FsCCQx MXF1Wu1NOpPnwtDU8M+murk/0v0a0CT3VwJji5qoHThK1Pi01H7kOVjyF YnzYn8aFQkGlZqrSl/inDnoyCQ8TZaQyGxOhdGNfNq5fFDbpBIOrYWtpQ OcMfLIntXhIsGErsuFzXDc2ZZewzAhFLz0rlO1M/av3eW1FML8L3sqQy3 k+++1e9g9PEMeNWL3c+3jaGmp0mIJssO99YKrkYBIjqqVuYk9sydIpo0G +hZ2xTTAf7cU3KBXapZNI3of/VwkFEhyGgGkJq/pM6/fjZkaxKdwUbsp1 A==; X-IronPort-AV: E=McAfee;i="6400,9594,10406"; a="268101485" X-IronPort-AV: E=Sophos;i="5.92,266,1650956400"; d="scan'208";a="268101485" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jul 2022 16:13:30 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.92,266,1650956400"; d="scan'208";a="628074991" Received: from black.fi.intel.com ([10.237.72.28]) by orsmga001.jf.intel.com with ESMTP; 12 Jul 2022 16:13:26 -0700 Received: by black.fi.intel.com (Postfix, from userid 1000) id E6AAB3ED; Wed, 13 Jul 2022 02:13:29 +0300 (EEST) 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 , linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: [PATCHv5 05/13] x86/uaccess: Provide untagged_addr() and remove tags before address check Date: Wed, 13 Jul 2022 02:13:20 +0300 Message-Id: <20220712231328.5294-6-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220712231328.5294-1-kirill.shutemov@linux.intel.com> References: <20220712231328.5294-1-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1657667610; a=rsa-sha256; cv=none; b=Q+GGIvHfEfuZRYa2C+miG0EfX0upuwehojl6o7fc9A16O/1H2jlupaA9QEDumuxVZ976uX F25LQtRwVvs6CrCwoiBnKB+fyxw1Gn1Lhp01UidPrh6ZEY+RIyck+qBN20JZrfuCyMGgdR ythzSZwfgxsZDq1gGgZEf6Dru31yLfU= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=nWngtr4y; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf03.hostedemail.com: domain of kirill.shutemov@linux.intel.com has no SPF policy when checking 134.134.136.126) 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=1657667610; 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=twRlpS3YtzZOcwl3Jo6mKYeJnht9rBQ9NxnDiRzNiRc=; b=AwdsoY5JgYPf2pnej81EGtvRlGF1ktqvY1H9C17bGzIfM7SRlWYryi+IEa7YG0O1UOLQ4c 7Umxddcx+Jem5gvELp4FMvv4dt6ylXCTg4UTOiIZyadQ3TGXnKt7TJZSohWe2qKzkla9rj JJFUkCM8ZcbknTn32fUDrizashU/k2Y= X-Stat-Signature: tsehttx55gxikh1eg87e4yxnqczept5o X-Rspamd-Queue-Id: 7D8EC20039 Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=nWngtr4y; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf03.hostedemail.com: domain of kirill.shutemov@linux.intel.com has no SPF policy when checking 134.134.136.126) smtp.mailfrom=kirill.shutemov@linux.intel.com X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1657667610-601294 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 --- 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 913e593a3b45..803241dfc473 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -6,6 +6,7 @@ */ #include #include +#include #include #include #include @@ -20,6 +21,30 @@ 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 @@ -40,7 +65,7 @@ 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 @@ -125,7 +150,13 @@ 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. @@ -222,7 +253,12 @@ 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 9b2772b7e1f3..18b2bfdf7b9b 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