From patchwork Tue Oct 18 11:33:48 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: 13010292 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 D8BB0C4332F for ; Tue, 18 Oct 2022 11:34:21 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 767F18E0005; Tue, 18 Oct 2022 07:34:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7226E8E0003; Tue, 18 Oct 2022 07:34:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4F5B88E0005; Tue, 18 Oct 2022 07:34:21 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 360008E0001 for ; Tue, 18 Oct 2022 07:34:21 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id F1C0E141055 for ; Tue, 18 Oct 2022 11:34:20 +0000 (UTC) X-FDA: 80033861880.06.78A9C51 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by imf06.hostedemail.com (Postfix) with ESMTP id 65A8218002D for ; Tue, 18 Oct 2022 11:34:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1666092860; x=1697628860; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=URl4+yXuTZU7i5eHga9UDkYb72zi7S2whgUd+vZqeAk=; b=LFdGXacKRPGuGyvWp/bUcL4itXXDGxNs/SOe26JuvvnwyvUybD/dlJV/ bSLOdv/fblzwj4I6biXaUui5i/dROVmRLL4JV/mot9dnqLg5t6zxi8K0g yPzNjwfrhJzIupJfw/fJxUOKwBzJ2JDQ1KpepvBOKFZMKhBSfR/Ehbfag F8Z57m8XV9J+1STZKLIwld35chyWIgFS/7VVnTyvujRPEVIRJdEZNuEJj QmmJCI4HXueISbnwq/V4ekDSFkJMRbhJFIMAGkpm3yFDp3bdgJHNqS8dQ HcD8s4Aius+ND6JqtjY7nOKAzhR0HOFSFMeIScjfil4F2Ceq5tZAVWQOl A==; X-IronPort-AV: E=McAfee;i="6500,9779,10503"; a="370276026" X-IronPort-AV: E=Sophos;i="5.95,193,1661842800"; d="scan'208";a="370276026" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Oct 2022 04:34:17 -0700 X-IronPort-AV: E=McAfee;i="6500,9779,10503"; a="691763173" X-IronPort-AV: E=Sophos;i="5.95,193,1661842800"; d="scan'208";a="691763173" Received: from vhavel-mobl.ger.corp.intel.com (HELO box.shutemov.name) ([10.252.51.115]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Oct 2022 04:34:13 -0700 Received: by box.shutemov.name (Postfix, from userid 1000) id 252BC1046FB; Tue, 18 Oct 2022 14:34:04 +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: [PATCHv10 05/15] x86/uaccess: Provide untagged_addr() and remove tags before address check Date: Tue, 18 Oct 2022 14:33:48 +0300 Message-Id: <20221018113358.7833-6-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.38.0 In-Reply-To: <20221018113358.7833-1-kirill.shutemov@linux.intel.com> References: <20221018113358.7833-1-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=LFdGXacK; spf=none (imf06.hostedemail.com: domain of kirill.shutemov@linux.intel.com has no SPF policy when checking 134.134.136.100) smtp.mailfrom=kirill.shutemov@linux.intel.com; dmarc=fail reason="No valid SPF" header.from=intel.com (policy=none) ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1666092860; a=rsa-sha256; cv=none; b=cslIilwqn8OzSxo0I+FU4pk4xMEz861KWft0XwIJRrK0LH65OZygA9KgawWFAmO3Gh8j4u iKFyqwpO3VXDwBNYN4N4QH8FWydktbSTVl7NgvSddwpfN+WvVWJ+K8nZJklZKTyFZbKunt eSrycZROnJMfQkVMMJFGaROduz/csz4= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1666092860; 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=BLOLR5ccd2aZdnWXYjcgWwcZh/64JYPdm9FkptVwF2Ohh3/JtdsT3D30O0uRpppvzokVAx 5jA87GUMhoS4mTNFhnJni8hSXB8gZEG0EvzWuVGuM6/IZo5gcvw/KLeGWixRvxwinflLTP AoL8Tulo/eRu1hFyiP00Rr5gn5utcwo= X-Stat-Signature: jsaexh1az5kourp1z3jf7zqt684jezwh X-Rspamd-Queue-Id: 65A8218002D Authentication-Results: imf06.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=LFdGXacK; spf=none (imf06.hostedemail.com: domain of kirill.shutemov@linux.intel.com has no SPF policy when checking 134.134.136.100) smtp.mailfrom=kirill.shutemov@linux.intel.com; dmarc=fail reason="No valid SPF" header.from=intel.com (policy=none) X-Rspam-User: X-Rspamd-Server: rspam01 X-HE-Tag: 1666092860-867074 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) --- 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