From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-13.6 required=5.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 8702A7D099 for ; Fri, 15 Mar 2019 19:51:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727250AbfCOTv5 (ORCPT ); Fri, 15 Mar 2019 15:51:57 -0400 Received: from mail-qt1-f202.google.com ([209.85.160.202]:42891 "EHLO mail-qt1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727295AbfCOTvy (ORCPT ); Fri, 15 Mar 2019 15:51:54 -0400 Received: by mail-qt1-f202.google.com with SMTP id n10so2019764qtk.9 for ; Fri, 15 Mar 2019 12:51:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=yc2TKKK3uyNjx4k/SCg2YsIAkDocczWLqEwyHrZeSHg=; b=HPKtN+AcCirGFFQHEZAu/mCbNrjYIKj90qShdg/IiFhxen49J0Qdpnr1pcKG7a6Z8e JeJ2qVhpKVo0e4MFSlZbzLIR2woDetJaTNND5bdihZ/qbAWcocsa2cvfjheYeB4rsRtq VupfRDNmC+dOLdGj40kTGJqU/K4oyQ4V3HkdkM9xosZcLU7jdIpJBpWnC76XUdwc2cRx PrBSQsPpZWMh+HxdTYEIi4nHU5c8m+m6PJBso4DlJCsFDkKaGHF5sF+vigRkHjI5UG0U RhfFgSuDuzmav8L6Qcw6zbyS+BybgMK3vA4F1h2a+P/7Y7SKXtGu14CbY9cr1/NstkUy Z8Lw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=yc2TKKK3uyNjx4k/SCg2YsIAkDocczWLqEwyHrZeSHg=; b=phFMDAxtyH7puo3hS6BfLEaNV9uhd86UD33umzH8rs6Hb/rcVuaJmfSdaGvjR3IKqQ 4yYesmdB5wudLavA1iJddUIRROmg+0bhl6i1LKsfEhfaOczGqazyx34VCCelLRHQUEJK aYA4E4iA+PyUbCRRL7kt+4qOlJAu+6vsKceDYiirhatMAPvwN74hqhhywFFCxuUvv7ki 1QTFLRYsGaz4dlml/XrycJ0l7wfC5R6J2DN0jwuA8BXz+Llw5yObWxHvPlVtOdqgn3f+ QeocgncCLaEqGvjoNeQffnwVwc7tjsN4gG3MmWs5mMQb45qAKixK86nlPHUcr7qmOVck /AaA== X-Gm-Message-State: APjAAAWk23g3dvGSOK8VV705lGmASeYGCS/xnOJXf9x7ELUkutsWnz7i RcMy4cLPhViE28SookFSXhrmP+akKsVPylH8 X-Google-Smtp-Source: APXvYqxQt9HPpRfECab7LUPrHAbJSVnQOqRrkiVNkyIaCkT/+WBTjFpEfz28zU++TxipH2bwdLb5/hvYcjvCwg1k X-Received: by 2002:ac8:28c9:: with SMTP id j9mr3165248qtj.21.1552679513588; Fri, 15 Mar 2019 12:51:53 -0700 (PDT) Date: Fri, 15 Mar 2019 20:51:27 +0100 In-Reply-To: Message-Id: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.21.0.360.g471c308f928-goog Subject: [PATCH v11 03/14] lib, arm64: untag user pointers in strn*_user From: Andrey Konovalov To: Catalin Marinas , Will Deacon , Mark Rutland , Robin Murphy , Kees Cook , Kate Stewart , Greg Kroah-Hartman , Andrew Morton , Ingo Molnar , "Kirill A . Shutemov" , Shuah Khan , Vincenzo Frascino , Eric Dumazet , "David S. Miller" , Alexei Starovoitov , Daniel Borkmann , Steven Rostedt , Ingo Molnar , Peter Zijlstra , Arnaldo Carvalho de Melo , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Dmitry Vyukov , Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan , Chintan Pandya , Luc Van Oostenryck , Dave Martin , Kevin Brodsky , Szabolcs Nagy , Andrey Konovalov Content-Type: text/plain; charset="UTF-8" Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org This patch is a part of a series that extends arm64 kernel ABI to allow to pass tagged user pointers (with the top byte set to something else other than 0x00) as syscall arguments. strncpy_from_user and strnlen_user accept user addresses as arguments, and do not go through the same path as copy_from_user and others, so here we need to handle the case of tagged user addresses separately. Untag user pointers passed to these functions. Note, that this patch only temporarily untags the pointers to perform validity checks, but then uses them as is to perform user memory accesses. Signed-off-by: Andrey Konovalov --- lib/strncpy_from_user.c | 3 ++- lib/strnlen_user.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/lib/strncpy_from_user.c b/lib/strncpy_from_user.c index 58eacd41526c..6209bb9507c7 100644 --- a/lib/strncpy_from_user.c +++ b/lib/strncpy_from_user.c @@ -6,6 +6,7 @@ #include #include #include +#include #include #include @@ -107,7 +108,7 @@ long strncpy_from_user(char *dst, const char __user *src, long count) return 0; max_addr = user_addr_max(); - src_addr = (unsigned long)src; + src_addr = (unsigned long)untagged_addr(src); if (likely(src_addr < max_addr)) { unsigned long max = max_addr - src_addr; long retval; diff --git a/lib/strnlen_user.c b/lib/strnlen_user.c index 1c1a1b0e38a5..8ca3d2ac32ec 100644 --- a/lib/strnlen_user.c +++ b/lib/strnlen_user.c @@ -2,6 +2,7 @@ #include #include #include +#include #include @@ -109,7 +110,7 @@ long strnlen_user(const char __user *str, long count) return 0; max_addr = user_addr_max(); - src_addr = (unsigned long)str; + src_addr = (unsigned long)untagged_addr(str); if (likely(src_addr < max_addr)) { unsigned long max = max_addr - src_addr; long retval; -- 2.21.0.360.g471c308f928-goog