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 X-Spam-Level: X-Spam-Status: No, score=-16.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 66F56C4360F for ; Fri, 29 Mar 2019 21:47:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2E83A218D3 for ; Fri, 29 Mar 2019 21:47:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Q8Ossw+h" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730351AbfC2VrL (ORCPT ); Fri, 29 Mar 2019 17:47:11 -0400 Received: from mail-it1-f202.google.com ([209.85.166.202]:36023 "EHLO mail-it1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729998AbfC2VrK (ORCPT ); Fri, 29 Mar 2019 17:47:10 -0400 Received: by mail-it1-f202.google.com with SMTP id l202so3500025ita.1 for ; Fri, 29 Mar 2019 14:47:09 -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=BIUYSdViMIn+To2mUC3qZ7zEN+7GQ3ySY+V/Ekd7gP4=; b=Q8Ossw+hkgnOCqCCmDlkaB7INGKnnX/7XqFXcKnoxXj/6IR9rdXMn1eAfOnQAfHSCT m5BeHO8EWmf2c6BIYwp6PdlKGhI6ShBMM6cXt+rBdSAhe7/Rh5YiIksh4CtpRzijg1qo tV6ArUbKs3AB7BWgOtRAbgWGvaXaX5mGVVyuzxwTdGBQk3qeITV8HlpazvQFhV/dln2P 8quJN+t0pFFsPlRVZOX4CJZAdOa/PHbJ0oYA9cjDcH9U/HmXwz1MkjOANht8NAs/pPHK 2+8wong01mhW4uGhFW4XZqOzDm+FQoAcnSnPsiB1MG7atw/npWT0MAUqWkqkZR7Dxieb MZ0g== 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=BIUYSdViMIn+To2mUC3qZ7zEN+7GQ3ySY+V/Ekd7gP4=; b=MrT3Z+xUo8gZASK++FN3Di03DurgJ1lkQfYU+rQyyslt1sR6FkUozuMTeITmiDcego ED3+twVkToJgzd1xeAZ+C9yRBPXEEyU40709RxPvgtSPrbjW4CRbqvnWdPFzmOqK1ILj fKfvhXL7yYu7cpkYZ7YpSWkmWeitGGDzukfvKG9Y5dsnafjn0RWxkRgQ4OgEY1cm+Ln3 4GA/K15FZsErKKS4kcwzLvYeh+ggfq09hdxLzLQfmIftYeapFNSbFQZP6p1Fgthy5kgD uUtgLcsO/bOVs+Bg2yMe5CNQN//qvKHDxXvuoBg7sUxJnX1+8K3FOEAZ0zZx3BVuLwCc YkFA== X-Gm-Message-State: APjAAAWywy294R5F2GAn1ztx7lYfX0WZEnnezDrLrctdNYKDEPVvOoqB 88gWde94c4HmHjtbPHZIWq19Jelvtw== X-Google-Smtp-Source: APXvYqwowR9WlAl7Fp/7MzuCpLf7ifuupDP7KotIgItUt3ZXdaHLyxYhEOMqnBWfypAOnOrYsYJleUSfsA== X-Received: by 2002:a24:9fc4:: with SMTP id c187mr2332485ite.23.1553896029431; Fri, 29 Mar 2019 14:47:09 -0700 (PDT) Date: Fri, 29 Mar 2019 22:46:50 +0100 In-Reply-To: <20190329214652.258477-1-jannh@google.com> Message-Id: <20190329214652.258477-2-jannh@google.com> Mime-Version: 1.0 References: <20190329214652.258477-1-jannh@google.com> X-Mailer: git-send-email 2.21.0.392.gf8f6787159e-goog Subject: [PATCH v3 2/4] x86/microcode: Fix __user annotations around generic_load_microcode() From: Jann Horn To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , jannh@google.com Cc: x86@kernel.org, linux-kernel@vger.kernel.org, Qiaowei Ren , Mukesh Ojha Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org generic_load_microcode() deals with a pointer that can be either a kernel pointer or a user pointer. Pass it around as a __user pointer so that it can't be dereferenced accidentally while its address space is unknown. Use explicit casts to convert between __user and __kernel to inform the checker that these address space conversions are intentional. Signed-off-by: Jann Horn --- arch/x86/kernel/cpu/microcode/intel.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c index 16936a24795c..e8ef65c275c7 100644 --- a/arch/x86/kernel/cpu/microcode/intel.c +++ b/arch/x86/kernel/cpu/microcode/intel.c @@ -861,11 +861,13 @@ static enum ucode_state apply_microcode_intel(int cpu) return ret; } -static enum ucode_state generic_load_microcode(int cpu, void *data, size_t size, - int (*get_ucode_data)(void *, const void *, size_t)) +static enum ucode_state generic_load_microcode(int cpu, + const void __user *data, size_t size, + int (*get_ucode_data)(void *, const void __user *, size_t)) { struct ucode_cpu_info *uci = ucode_cpu_info + cpu; - u8 *ucode_ptr = data, *new_mc = NULL, *mc = NULL; + const u8 __user *ucode_ptr = data; + u8 *new_mc = NULL, *mc = NULL; int new_rev = uci->cpu_sig.rev; unsigned int leftover = size; unsigned int curr_mc_size = 0, new_mc_size = 0; @@ -945,9 +947,10 @@ static enum ucode_state generic_load_microcode(int cpu, void *data, size_t size, return ret; } -static int get_ucode_fw(void *to, const void *from, size_t n) +static int get_ucode_fw(void *to, const void __user *from, size_t n) { - memcpy(to, from, n); + /* cast paired with request_microcode_fw() */ + memcpy(to, (const void __force *)from, n); return 0; } @@ -993,7 +996,8 @@ static enum ucode_state request_microcode_fw(int cpu, struct device *device, return UCODE_NFOUND; } - ret = generic_load_microcode(cpu, (void *)firmware->data, + /* cast paired with get_ucode_fw() */ + ret = generic_load_microcode(cpu, (void __force __user *)firmware->data, firmware->size, &get_ucode_fw); release_firmware(firmware); @@ -1001,7 +1005,7 @@ static enum ucode_state request_microcode_fw(int cpu, struct device *device, return ret; } -static int get_ucode_user(void *to, const void *from, size_t n) +static int get_ucode_user(void *to, const void __user *from, size_t n) { return copy_from_user(to, from, n); } @@ -1012,7 +1016,7 @@ request_microcode_user(int cpu, const void __user *buf, size_t size) if (is_blacklisted(cpu)) return UCODE_NFOUND; - return generic_load_microcode(cpu, (void *)buf, size, &get_ucode_user); + return generic_load_microcode(cpu, buf, size, &get_ucode_user); } static struct microcode_ops microcode_intel_ops = { -- 2.21.0.392.gf8f6787159e-goog