From patchwork Mon Apr 10 16:44:18 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Garnier X-Patchwork-Id: 9673349 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id C1BA9600CB for ; Mon, 10 Apr 2017 16:45:04 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C25D52811C for ; Mon, 10 Apr 2017 16:45:04 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B5CD22823E; Mon, 10 Apr 2017 16:45:04 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED,DKIM_VALID autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [65.50.211.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id EBD022811C for ; Mon, 10 Apr 2017 16:45:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=6iTPHEKljmty4H2TnZwckMhCMek9oRrrlkC5eyckeqk=; b=ARpp109AmgWNxfOLzdI0SbiWji Mo8NO4E3YEta+S/UIZUyrRo35xi146QLWCMZTmr+zqAvFUyLoeaRninpYylO7M+9An86S24f0Eyk2 Z0fJBma43miWqVDDSkpJytd/RqWuf1XSW5qp/mXUTFXQo9jhqoCQyx1/DYtAyRqjCCDrLJuIIecxi fwuRet7ORCdLS6eruFvBJUlq9zD+5ojxf7B/zd3T5nOEAanL52LsKvPZP/YOzpoNAPAhgV8wwA738 JOBatqLXTGS4Fah77hvmfEfuKgIW/TI8oHo9tEM/uO+xm0zjLfDvoyAwjtdOXLOK93vCaA09cqgEb sSg6ax4A==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1cxcR4-0001Gc-4D; Mon, 10 Apr 2017 16:45:02 +0000 Received: from mail-pg0-x22c.google.com ([2607:f8b0:400e:c05::22c]) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1cxcQp-0000f4-Qr for linux-arm-kernel@lists.infradead.org; Mon, 10 Apr 2017 16:44:49 +0000 Received: by mail-pg0-x22c.google.com with SMTP id x125so108634853pgb.0 for ; Mon, 10 Apr 2017 09:44:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=VzI1LPxuOA2LNykf/VrSuwao+DJFkpwXfUHz17i1BgA=; b=dVk4gLbS4A5qBTVgKTyOg4a4NNOhTcQcqIYCO18yiHV7VUu34IpWKo0SZNGY1NZg0f tk48qSftop11nSNEGsncqC4TOFsbxKq6doYXEOVyhlKHiDyf/XOwTUs0dG0Hx6em+3ua VJRtBTdSLozuKfAYwwTl5h5BNIUHaWfpHglOmpKtyPKCgKcPGDhP0/CDV/m9FWWWbGlE B3VIja7DPrKGQPWczx3wB08mAqkBTNWaH1S8Q48pOzPELiBmOd2TTJgL5PiRATUkio7E 67BLUpiTB+BclfAM9MIzYtE01j0utMEQfJFrJRfS4YlWXOuw51UaCZJNSIJYUSSNBGK9 YDKw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=VzI1LPxuOA2LNykf/VrSuwao+DJFkpwXfUHz17i1BgA=; b=BQxfzggUP0M7uzIOoWoREQpVzDJG5b9hkHWnH5s1ZjARQPRuC5LFIv8gwQ6dK5H8Mh AVZV2S37U+43hTIfpYncBw+DgsxIdRF7WPFZI58SufR9J5uzHK4kcXN/h6W9FocU6J+Q QAnd3s/win0kVeuuc4KaqWKvzOuFE3GWIpOpT3h4pbk50noERS5ZijCQndRmpVmd3ZmS uigc+6QfqrHoZX1I/KOTFdwFrtyLdHWJmwOjQSXJkHsVmdzK6d7oCRu4kgtGfILvJqf+ vW4cKWGJac/LxPzxlFcMklcDYODmxOe3yoxnWbqZyQPjHnbALbl6JwevuUSJYqSYU4Iv GXfQ== X-Gm-Message-State: AFeK/H1ovEuEskPpMlpFXPi55eSJP/dBLxcSzU9YoIQ42ObTdn2S0mNZJ42tWni3m6zfa55i X-Received: by 10.98.60.141 with SMTP id b13mr25266826pfk.137.1491842666579; Mon, 10 Apr 2017 09:44:26 -0700 (PDT) Received: from skynet.sea.corp.google.com ([100.100.206.164]) by smtp.gmail.com with ESMTPSA id n7sm25743254pfn.0.2017.04.10.09.44.25 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 10 Apr 2017 09:44:25 -0700 (PDT) From: Thomas Garnier To: Martin Schwidefsky , Heiko Carstens , Arnd Bergmann , Dave Hansen , Andrew Morton , Thomas Garnier , David Howells , =?UTF-8?q?Ren=C3=A9=20Nyffenegger?= , "Paul E . McKenney" , Ingo Molnar , Thomas Gleixner , Oleg Nesterov , Stephen Smalley , Pavel Tikhomirov , Ingo Molnar , "H . Peter Anvin" , Andy Lutomirski , Paolo Bonzini , Kees Cook , Rik van Riel , Josh Poimboeuf , Borislav Petkov , Brian Gerst , "Kirill A . Shutemov" , Christian Borntraeger , Russell King , Will Deacon , Catalin Marinas , Mark Rutland , James Morse Subject: [PATCH v7 2/4] x86/syscalls: Architecture specific pre-usermode check Date: Mon, 10 Apr 2017 09:44:18 -0700 Message-Id: <20170410164420.64003-2-thgarnie@google.com> X-Mailer: git-send-email 2.12.2.715.g7642488e1d-goog In-Reply-To: <20170410164420.64003-1-thgarnie@google.com> References: <20170410164420.64003-1-thgarnie@google.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20170410_094447_954436_CC963C5F X-CRM114-Status: GOOD ( 19.71 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-s390@vger.kernel.org, kernel-hardening@lists.openwall.com, linux-api@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP Disable the generic pre-usermode check in favor of an optimized implementation. This patch adds specific checks on user-mode return path to make it faster and smaller. The user-mode state check is added to the prepare_exit_to_usermode function. This function is called before any user-mode return on 32-bit and on the 64-bit syscall slowpath. For the 64-bit syscall fast path, an assembly address limit check redirects to the slow path if the address limit is different. The TASK_SIZE_MAX define is moved to the pgtable_64_types header so it can be used in assembly code. Signed-off-by: Thomas Garnier --- Based on next-20170410 --- arch/x86/Kconfig | 1 + arch/x86/entry/common.c | 3 +++ arch/x86/entry/entry_64.S | 8 ++++++++ arch/x86/include/asm/pgtable_64_types.h | 11 +++++++++++ arch/x86/include/asm/processor.h | 11 ----------- 5 files changed, 23 insertions(+), 11 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index c43f47622440..74185795eb24 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -63,6 +63,7 @@ config X86 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI select ARCH_MIGHT_HAVE_PC_PARPORT select ARCH_MIGHT_HAVE_PC_SERIO + select ARCH_NO_SYSCALL_VERIFY_PRE_USERMODE_STATE select ARCH_SUPPORTS_ATOMIC_RMW select ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index cdefcfdd9e63..76ef050255c9 100644 --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -23,6 +23,7 @@ #include #include #include +#include #include #include @@ -183,6 +184,8 @@ __visible inline void prepare_exit_to_usermode(struct pt_regs *regs) struct thread_info *ti = current_thread_info(); u32 cached_flags; + verify_pre_usermode_state(); + if (IS_ENABLED(CONFIG_PROVE_LOCKING) && WARN_ON(!irqs_disabled())) local_irq_disable(); diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 607d72c4a485..62aca6dcdaf4 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -218,6 +218,14 @@ entry_SYSCALL_64_fastpath: testl $_TIF_ALLWORK_MASK, TASK_TI_flags(%r11) jnz 1f + /* + * If address limit is not based on user-mode, jump to slow path for + * additional security checks. + */ + movq $TASK_SIZE_MAX, %rcx + cmp %rcx, TASK_addr_limit(%r11) + jne 1f + LOCKDEP_SYS_EXIT TRACE_IRQS_ON /* user mode is traced as IRQs on */ movq RIP(%rsp), %rcx diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h index 06470da156ba..78af4d43a7ce 100644 --- a/arch/x86/include/asm/pgtable_64_types.h +++ b/arch/x86/include/asm/pgtable_64_types.h @@ -104,4 +104,15 @@ typedef struct { pteval_t pte; } pte_t; #define EARLY_DYNAMIC_PAGE_TABLES 64 +/* + * User space process size. 47bits minus one guard page. The guard + * page is necessary on Intel CPUs: if a SYSCALL instruction is at + * the highest possible canonical userspace address, then that + * syscall will enter the kernel with a non-canonical return + * address, and SYSRET will explode dangerously. We avoid this + * particular problem by preventing anything from being mapped + * at the maximum canonical address. + */ +#define TASK_SIZE_MAX ((_AC(1, UL) << 47) - PAGE_SIZE) + #endif /* _ASM_X86_PGTABLE_64_DEFS_H */ diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 3cada998a402..e80822582d3e 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -825,17 +825,6 @@ static inline void spin_lock_prefetch(const void *x) #define KSTK_ESP(task) (task_pt_regs(task)->sp) #else -/* - * User space process size. 47bits minus one guard page. The guard - * page is necessary on Intel CPUs: if a SYSCALL instruction is at - * the highest possible canonical userspace address, then that - * syscall will enter the kernel with a non-canonical return - * address, and SYSRET will explode dangerously. We avoid this - * particular problem by preventing anything from being mapped - * at the maximum canonical address. - */ -#define TASK_SIZE_MAX ((1UL << 47) - PAGE_SIZE) - /* This decides where the kernel will search for a free chunk of vm * space during mmap's. */