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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 19899C4332F for ; Fri, 30 Sep 2022 14:48:24 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 82EAC6B0075; Fri, 30 Sep 2022 10:48:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7B3AE6B0078; Fri, 30 Sep 2022 10:48:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5E0068D0001; Fri, 30 Sep 2022 10:48:21 -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 421B96B0078 for ; Fri, 30 Sep 2022 10:48:21 -0400 (EDT) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 110C51C5B78 for ; Fri, 30 Sep 2022 14:48:21 +0000 (UTC) X-FDA: 79969032402.24.B4390E5 Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by imf28.hostedemail.com (Postfix) with ESMTP id 5277CC0012 for ; Fri, 30 Sep 2022 14:48:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1664549299; x=1696085299; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=T/1SON8x3I6gBc9Gilj4Fh9sNy8RCIdk2WdRlZ6DEwk=; b=nvbjvIxtqIPxzEdzra8666ynul9xR8D9rBfd271PW8yx4fdFYdHedD0Y uUvNxBMDpIQNqSJa+zsdlU59RfuXr3SevcqmYAjMLTDE9MEZtyQqJf/AW wGODrvhSUtHcs/JPGoJxn+6X/yl5/vY0hPuzva3tRfOqWBxqRzIl8Fmuk zjuc2PubJeoeAfALI0dm289A3yIuAy/wlkdlPDKlEo8xR2UbYm2HuEaTi EI0PNJz5KUW0lSFRMT5PKY83ZQrPA5vKeFTmi6Yxp/YynOfxBK/QmNCOl U0RSc3ZEVtimprcr4akV79ex+sUWocfahyjTZNjbBvUv8O1RkMgg4OWaU Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10486"; a="299808866" X-IronPort-AV: E=Sophos;i="5.93,358,1654585200"; d="scan'208";a="299808866" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Sep 2022 07:48:16 -0700 X-IronPort-AV: E=McAfee;i="6500,9779,10486"; a="653563760" X-IronPort-AV: E=Sophos;i="5.93,358,1654585200"; d="scan'208";a="653563760" Received: from herrerop-mobl1.ger.corp.intel.com (HELO box.shutemov.name) ([10.252.38.128]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Sep 2022 07:48:11 -0700 Received: by box.shutemov.name (Postfix, from userid 1000) id 59A3A104CC1; Fri, 30 Sep 2022 17:48:02 +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: [PATCHv9 05/14] x86/uaccess: Provide untagged_addr() and remove tags before address check Date: Fri, 30 Sep 2022 17:47:49 +0300 Message-Id: <20220930144758.30232-6-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220930144758.30232-1-kirill.shutemov@linux.intel.com> References: <20220930144758.30232-1-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit ARC-Authentication-Results: i=1; imf28.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=nvbjvIxt; spf=none (imf28.hostedemail.com: domain of kirill.shutemov@linux.intel.com has no SPF policy when checking 192.55.52.93) 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=1664549299; a=rsa-sha256; cv=none; b=Q0DL8/pqsQYlG3EJuXuOBx+YsOA8GoZnJ08AKDzEM19Oc2Q3IEDCIH07DY94KK9CsGLqLv WOKqrmsgcAvwm6UrgJ8isii2vCoHoeuMRgOmiKH8uIw8v4x0th/0xMUKRwE4C5S9PsRFaV ae19r07m2Yj8pCWh8l7pFu3vC46zJU4= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1664549299; 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=+gpgieOlIPxx05fS70p4VSaJETO7zeherGqCBT59DhU=; b=5GDv3EstOpJqxNpHDAd3t6Ur3tBF4GaHjl5/xUBbuOIRIG1NjZcPaHTdyhPJsl/Hp6RV3I h9hMSf0/vKEwpU9xm4mnQo9xQnsgK/Pr+vttytvgYxkDLjLi/Bi+4jY2d5+EJNrvddMuB3 c2EfWM6r4gEE9ql0Cs/1S/mTL9nnKh4= X-Stat-Signature: 9m7df39t7grnu91r5sw5toszdua837nh X-Rspamd-Queue-Id: 5277CC0012 Authentication-Results: imf28.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=nvbjvIxt; spf=none (imf28.hostedemail.com: domain of kirill.shutemov@linux.intel.com has no SPF policy when checking 192.55.52.93) 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: rspam07 X-HE-Tag: 1664549299-791220 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 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 58a6ea472db9..b0e86fb11ffa 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 -- 2.35.1